Supplementary Material High-efficiency extraction of bromocresol purple dye and heavy metals as chromium from industrial effluent by adsorption onto a modified surface of zeolite: kinetics and equilibrium study Loai Aljerfa,* a
Department of Basic Sciences, Faculty of Dental Medicine, Damascus University, Mazzeh
Highway, AlMazzeh, Damascus, Syria Contents List of abbreviations, symbols, and nomenclatures............................................................4 Photos captured from the field (3/27/2016) and laboratory (6/14/2016)........................7 1. Onsite technical data for textile solid and water wastes.................................................8 2. Health issue....................................................................................................................9 3. Analytical methods..........................................................................................................10 4. Chemicals and reagents...................................................................................................12 5. Materials..........................................................................................................................13 6. Apparatuses.....................................................................................................................14 7. Reagent preparation.........................................................................................................14 8. Design of the chemical reactor........................................................................................15
a
Corresponding author.
E-mail addresses:
[email protected];
[email protected] (L. Aljerf).
1
8.1. Thickness of the shell calculation.............................................................................15 8.2. Thickness of head.....................................................................................................16 8.3. Thickness of jacket...................................................................................................16 8.4. Agitation calculations...............................................................................................17 8.4.1. Agitator thickness............................................................................................17 8.4.2. Agitator power calculations……………………………………….…….….…17 9. Digestion of SW with Aqua-Regia..................................................................................17 10. Preparation of BCP calibration series..............................................................................18 11. BCP absorption spectrum................................................................................................18 12. BCP calibration series......................................................................................................18 13. Obstacles related to dye removal from the effluent of this industry and characterization of IWW.................................................................................................................................19 14. Characterization of SW....................................................................................................22 15. BCP distributions in IWW and SW.................................................................................23 16. Characterization of the modified adsorbent (CL-SW) surface........................................27 17. Liquid to solid (L/S) ratio................................................................................................27 18. S/N ratio...........................................................................................................................28 19. Kinetic rate equations.......................................................................................................28 20. Adsorption activation energy (𝐸𝑎 ).....................................................................................29 21. Adsorption isotherm models............................................................................................30 21.1. Langmuir.................................................................................................................30 21.2. Freundlich………………………………………………….…………….……..…..30 21.3. Temkin…………………………………………………….……………..…....……31 21.4. Langmuir-Freundlich (Sips)……………………………………….……...………..31 21.5. Isothermal parameters of BCP adsorption……………………….……….………32
2
22. Thermodynamic study.....................................................................................................34 23. Theoretical assessment of the adsorption capacity and percent removal of BCP dye....................................................................................................................................34 23.1. Application (dye adsorption)……… …………………………………..…………35 24. Zeta potential………………………………..…………………………..…………..……35 25. Impact of ionic strength...................................................................................................37 26. Comparative study of BCP dye adsorption capacity (mg/g) and its removal (%) with previous studies used zeolite as adsorbent.......................................................................38 27. Analytical conditions for tCr measurement by direct flame atomic absorption spectroscopy (FL-AAS) ..................................................................................................40 28. tCr calibration series by FL-AAS....................................................................................41 29. Analytical performance for tCr measurement by FL-AAS..............................................41 30. tCr distributions in IWW and SW...................................................................................42 31. IR characterization of the modified adsorbent................................................................45 32. Cr (III) distribution species with pH change...................................................................47 33. Cr nature in the alkaline medium.....................................................................................48 34. Effect of agitation rate.....................................................................................................49 35. Separation factors.............................................................................................................50 35.1. For dye………………………………………………………………………......….50 35.2. For tCr………………………………………………………………………..…….51 36. Theoretical assessment of the adsorption capacity and percent removal of tCr................51 37. X-ray photoelectron spectroscopy analysis......................................................................51 38. Effect of coexisting metal ions.......................................................................................53 39. Biodegradability...............................................................................................................54 40. Suitability for irrigation of the industrial wastewater after treatment..............................54
3
41. Selectivity removal of heavy metals................................................................................56 41.1. Electron density mapping and MicroAnalysis…………………………………….56 42. RSM experimental design and optimization....................................................................59 43. CL-SW a potential greener adsorbent..............................................................................59 References........................................................................................................................60 List of abbreviations, symbols, and nomenclatures AAS
– Atomic Absorption Spectroscopy
APHA
– American Public Health Association
ASTM
– American Society for Testing Materials
ATR
– Attenuated Total Reflection
ATSDR
– Agency for Toxic Substances and Disease Registry
B
– Langmuir constant (L/mg)
BCP
– Bromocresol purple
BET
– Brunauer–Emmett–Teller
BI
– Biodegradability index
BOD5
– 5-Day Biochemical Oxygen Demand (mg/L)
BSE
– Backscattered electron
C
– Corrosion resistance
Co
– Initial concentration of adsorbate (mg/L)
Ce
– Equilibrium concentration of the dye or tCr in the solution (mg/L)
Ct
– Concentration of adsorbate at time t (mg/L)
CL
– Clinoptilolite
COD
– Chemical Oxygen Demand (mg/L)
Conc.
– Concentration (mg/L or µm)
4
Cp
– Empirical Constant of the flat head
CV
– Coefficient of variation (%)
Da
– Diameter of the agitator blade (cm)
dd-DI
– Doubly distilled deionized water
H2O De
– Equivalent diameter (cm)
Di
– Internal diameter (cm)
Dj
– Diameter of jacket (cm)
Dt
– Internal diameter of the reactor (cm)
DO
– Dissolved oxygen
dp
– Pore size (nm)
EWM
– Environmentally waste management
ΔG°
– Standard Gibbs free energy change (kJ/mol)
ΔH°
– Standard enthalpy (kJ/mol)
ΔS°
– Standard entropy (J/mol.K)
E
– Rate of energy utilization (MJ/kg)
EC
– Electrical conductivity (mS/m)
EDAX
– Energy Dispersive X-ray
Φ
– Industrial flow rate (m3/day)
f
– Allowable stress (kgf/cm2)
FE-SEM
– Field Emission-Scanning Electron Microscopy
FL-AAS
– Flame - Atomic Absorption Spectroscopy
GF-AAS – Graphite Furnace-Atomic Absorption Spectroscopy H
– Reactor‟s height (cm)
IC
– Ion Chromatography
5
IWW
– Industrial Wastewater
J
– Joint Efficiency
Kc
– Adsorption equilibrium constant
ki
– Binding constant
λmax
– Maximum wavelength (nm)
L
– Length of the reactor (cm)
LDPE
– Low-density polyethylene
LOD
– Lower limit of detection (µM)
m
– Dry weight of solid waste (g)
µ
– Viscosity of the agitated fluid (kg/m/sec)
n
– Sample size
NTU
– Nephelometric Turbidity Unit
P
– Atmospheric pressure (kgf/cm2)
PI
– Permeability index
qe
– Equilibrium adsorption capacity (mg dye or tCr/g adsorbent)
qm
– Maximum adsorption capacity (mg dye or tCr/g adsorbent)
r
– Correlation coefficient
R
– Gas constant (8.31451 J/mol.K)
RSC
– Residual sodium carbonate index (meq/L)
RSD
– Relative standard deviation
RSM
– Response surface methodology
SA
– Surface area (m2/g)
SBET
– BET surface area (m2/g)
SD
– Standard deviation
SE
– Standard error
6
SW
– Solid Waste
t
– Residence time (s)
tCr
– Total chromium (Cr(III) and Cr(IV))
TDS
– Total dissolved solids (mg/L)
TOG
– Total oil and grease (mg/L)
TSS
– Total suspended solids (mg/L)
ʋ
– Effluent velocity (m/s)
Var.
– Variance
Vp
– Pore volume (cm3/g)
Vw
– Volume of water consumption (L)
XPS
– X-ray photoelectron spectrometer or electron spectroscopy for chemical analysis
Photos captured from the field (3/27/2016) and laboratory (6/14/2016)
Fig. S1. Study archive photos. Solution A: After bromocresol purple (BCP) dye and total chromium (tCr) removals, and solution B: The effluent before BCP dye and tCr removals; IWW: Industrial wastewater; SW: Solid waste. 7
Fig. S2. Schematic representation of the tanning process applied in the factory.
1. Onsite technical data for textile solid and water wastes Wastewater samples were collected at the discharge point of a textile plant in Adra industrial area (53 km north-east of Damascus-Syria; 71.500sq. miles) for defining the waste physicochemical parameters. The technical data registered at the specified location were: water consuming (Vw) to manufacture 1 kg of fabrics, industrial flow rate (Φ) in the working day, effluent velocity (ʋ), wastewater residence time (t), dry weight of solid waste (SW) per 1 kg fabrics (m), and rate of energy utilization (E) as follows: 55-65 L, 4000-5000 m3/day, 3.5 m/s, 15 s, 520 g, and 2-25 MJ/kg product, respectively. On the other side, BCP dye contents are estimated by 11-49 mg/L (21-91 µM) and 662-2881 µg/kg in IWW and SW, respectively being visible to the naked eye (Fig. S1). 8
2. Health issue More seriously, most organic dyes are toxic, non-biodegradable, teratogenetic, carcinogenic, and mutagenic. The current view about the effects of IWW-related contaminants is two-sided. One is the acute toxic damages caused to human health and the other is the long-term effects due to exposure to trace amounts. The latter is as hazardous as the previous one and most of the time emerges nonspecifically, making detection difficult. In addition, some new contaminants cannot be treated easily with the traditional wastewater treatment equipment or purification processes. In many countries, contagious IWW-borne diseases have been almost eradicated; chemical contaminants are more a cause for concern. From our observations which met with Singh‟s book (Singh, 2017), BCP (C21H16Br2O5S) (and
its
derivatives
as
Bromocresol
green
(C21H14Br4O5S),
Bromothymol
blue
(C27H28Br2O5S), and Victoria blue (C29H32ClN3)) is harmful for humans, it can lead to shortness of breath, produces a burning sensation, vomiting, gastritis, and causes skin and eyes irritations. Moreover, BCP at high concentrations causes chest pain, headache, sweating too much, giddiness, painful micturition, high heart rate, shock, cyanosis, and jaundice. Hence, the BCP in IWW is hazardous which presents a serious threat not even to human health but also to aquatic organisms, so its elimination is necessary. Integration of the strategic decisions with tactical/operational decisions is needed. For example, with regard to the management of IWW and emission of greenhouse gases, new models can result in a saving up to a certain level.
9
3. Analytical methods Table S1 Analytical techniques, instrumentation, and methods used in the study. Analyte
Method
Referenced
Instrument
method Density
Gravimetric
M100
Hydrometer (ASTM
(Camlab
D5057,
Limited, 2010)
Cambridge, UK) Surface tension
Capillary Rise Method
2158D
(Kingsview (ASTM
Optical
Limited, 2014)
D1331,
London, England) Turbidity
Nephelometric
2100Q
IS
(Hach, (ASTM
Colorado, USA) Viscosity
Low Temperature with TV7000LT Linearity Validation
D1889,
2007)
(P.M. (ASTM
D445,
Tamson Instruments 2015) BV, Bleiswijk the Netherlands)
BOD5
DO
Depletion: BODTrak
Incubation
II (ASTM
technique Respirometric BOD WK28466, 2008)
with
oxygen Apparatus
determinations
(Hach,
by Colorado, USA)
Winkler Method. COD
Titrimetric
following -
reflux distillation with acid
(ASTM 2010)
potassium 10
D6697,
dichromate DO
EC
Winkler's method with DR
1900
(Hach, (ASTM D888-e1,
azide modification
Colorado, USA)
2012)
Conductometry
MP-4
Portable (ASTM
Meter
(Hach, 2014)
D1125,
Colorado, USA) Ph
Potentiometry
CP-411
pH-Meter (ASTM
(Analyiso
D1293,
GmbH, 2012)
Greifswald, Germany) Color
ADMI Tristimulus Filter DR Method
1900
(Hach, (APHA, 2005)
Colorado, USA)
Grease and Oil IR absorption
ERACHECK
(ASTM D3921-96,
(TOG)
(eralytics Gmbh,
2011)
Vienna, Austria) As, Cd, Cr, Cu, Acid
extractable
and novAA
400
P (ASTM
Fe, Mn, Ni, Pb, AAS
(Analytik Jena AG , 2008)
and Zn
Jena, Germany)
Hg
Oxidation by potassium novAA
400
P (ASTM
D3919,
D3223,
persulfate and digestion (Analytik Jena AG , 2012)
NH4+
at 368.15 K
Jena, Germany)
Potentiometry
IntelliCAL
(ASTM
ISENH3181
2012)
Ammonia-Selective Electrode
11
(Hach,
D1426,
Colorado, USA) Cl-, NO3-, PO43-, Ion and SO42-
Chromatography Dionex
(IC)
(Thermo
ICS-900 (ASTM
D4327,
Scientific, 2011)
FL, USA) TDS
Gravimetric
(Drying MP-4
after filtration)
Portable (ASTM
Meter
D5907,
(Hach, 2013)
Colorado, USA) TSS
Gravimetric
(filtration DR
then drying at 378.15 K)
1900
(Hach, (ASTM
Colorado, USA)
D5907,
2013)
4. Chemicals and reagents The following items show the commercial sources and some characterizations of the purchased chemicals that used in the method section: -
Ammonium hydroxide (NH4OH), ACS, 28-30% (VWR, Radnor, PA, USA)
-
Bromocresol purple (BCP) indicator (C21H16Br2O5S), ACS, Reag Ph Eur grade, ≥ 99% (Merck-Millipore Co., Massachusetts, USA)
-
Chromium standard solution (tCr) (1000 mg/L ± 1% certified) (Thermo Fisher Scientific Oy, Vantaa, Finland)
-
Clinoptilolite (CL: Na81(AlO2)81(SiO2)111) (Jordan Phosphate Mines Company PLC, Shmeisani, Amman, Jordan)
-
Doubly distilled deionized water (dd-DI H2O) (Milli-Q Ultrapure water specifications: 18.2 MΩ/cm @ 25 °C (77 °F), TOC ≤ 5 ppb, Bacteria ≤ 1 CFU/mL), which is nonabsorbent under UV radiation, has been used throughout
-
Hydrochloric acid (HCl), BDH ARISTAR Ultra, 32-35% (VWR, Radnor, PA, USA)
12
-
Argon Gas (Ar), High Purity > 99.998% (Gas & Equipments Factory L.L.C, Abu Dhabi, UAE)
-
Nitrogen Gas (N2), High Purity > 99% (Gas & Equipments Factory L.L.C, Abu Dhabi, UAE)
-
Nitric acid (HNO3) 65%, ISO grade, ≥ 99.5% (Merck-Millipore Co., Massachusetts, USA)
-
Nitrous oxide (N2O), 99.9% (M.H. Almana Co., Doha, Qatar)
-
Non-ionic detergent (Hindustan Tex-Chem Industries, Bengaluru, Karnataka, India)
-
pH 4.0 and 7.0 buffer solutions (Sigma-Aldrich Chemie Gmbh, Munich, Germany)
-
Potassium permanganate (KMnO4), ACS reagent, 99% (Sigma-Aldrich Chemie Gmbh, Munich, Germany)
-
Salmiac (ammonium chloride) (NH4Cl), ACS reagent, 99.99% (Sigma-Aldrich Chemie Gmbh, Munich, Germany)
5. Materials Materials used in this study were listed as follows: -
Desiccator Nalgene, Thermo Scientific (Nalge Nunc Int., Rochester, NY, USA)
-
Gas mixing station-Dansensor MAP MIX 9000 (Cryogenservice LLC, Vyshneve, Ukraine)
-
Silica crucible (Avi Scientific, Thane, India)
-
Thermo Scientific Nalgene low-density polyethylene (LDPE) bottles, (Cole-Parmer International, Vernon Hills, Illinois, USA)
-
Transparent microcentrifuge Eppendorf plastic tubes with attached cap lids (Jack Chen Biologix Plastics Co., Ltd., Shanghai, China)
13
-
Whatman quantitative filter paper, ashless, Grade 42 (0.45 µm, 42.5 mm) (Sigma-Aldrich Chemie Gmbh, Munich, Germany)
6. Apparatuses -
Atomic absorption spectroscopy (AAS) (novAA 400 P, Analytik Jena AG , Jena, Germany)
-
CP-411 pH-Meter (Analyiso GmbH, Greifswald, Germany)
-
Disk mill (Model 3600, Perten Instruments, Huddinge, Switzerland )
-
Energy dispersive X-ray (EDAX) (Rigaku Mini Flex II, USA)
-
ERACHECK (eralytics Gmbh, Vienna, Austria)
-
Field Emission Scanning Electron Microscope (FE-SEM) (FEI Quanta 200F, Brno, Czech Republic)
-
Force 7 micro- centrifuge (Denver Instruments, Norfolk, UK)
-
Infrared Microscope (Nicolet iS 10, Thermo Fischer Scientific, Waltham, Massachusetts, USA)
-
Laboratory digital thermostatic sand bath (Zhangqui Meihua International Co., Ltd., Shandong, China)
-
Sartorius Cubis weighing balance (Sartorius AG, Gottingen, Germany)
-
Universal Oven UN30 (Memmert GmbH+Co. KG., Schwabach, Germany)
-
UV-Vis PerkinElmer Lambda 18 spectrophotometer (PerkinElmer, Massachusetts, USA)
-
X-ray photoelectron spectrometer (Supra, Shimadzu Analytical Pvt. Ltd., New Rajinder Nagar, Delhi, India)
7. Reagent preparation -
HCl (0.1 M): 8.3 mL of concentrated HCl (12 N) added to 991.7 mL of dd-DI H2O
-
HCl (1 M): 83 mL of concentrated HCl (12 N) added to 917 mL of dd-DI H2O 14
-
BCP (1 mM): 540.2 mg (to 1 mg) dissolved in 0.1 M HCl and diluted with dd-DI H2O to 1000 mL keeping the pH at the optimum range (4.8-5.1)
-
HNO3 (10% v/v): 105.9 mL (65% HNO3) diluted with 894.1 mL of dd-DI H2O in a 1000 mL volumetric flask
-
HNO3 (50% v/v): 529.5 mL (65% HNO3) diluted with 894.1 mL of dd-DI H2O in a 1000 mL volumetric flask
-
HNO3 (1 M): 68.6 mL (65% HNO3) was added to 250 mL of dd-DI H2O in a 1000 mL volumetric flask, then the final volume of the solution was adjusted to 1000 mL with ddDI H2O
-
KMnO4 (25 mM): 3.95 g (to 1 mg) of KMnO4 added to 250 mL of dd-DI H2O in a 1000 mL volumetric flask. The solution was stirred to dissolve then diluted to the mark with dd-DI H2O
-
Glassware rinsing solution: All glass components were rinsed by soaking each of them in acidified (nitric-permanganate) solution so these components were treated at first by 50% HNO3, washed by dd-DI H2O, followed by (25 mM) KMnO4 treatment; at last the glassware was rinsed several times again with dd-DI H2O
8. Design of the chemical reactor 8.1. Thickness of the shell calculation Length of the reactor (L): 80 cm Internal diameter (Di): 92 cm Expected maximum pressure = 80 kgf/cm2 Atmospheric pressure (P) = 80+1.01336 kgf/cm2 = 81.01336 kgf/cm2 Taking 110% safety factor, P = 81.01336 kgf/cm2 × 1.1 = 89.1 kgf/cm2 Joint Efficiency (J) = 0.8 (spot radiography) 15
Allowable Stress (f) = 1300 kgf/cm2 (for stainless steel) Corrosion Resistance (C) = 0 𝑃×𝐷𝑖
t = 2𝑓𝐽 −𝐷𝑖 + 𝐶
(1)
89.1×920
t = 2×1300 ×0.8−920 + 0 =
81972 1160
= 70.7 mm
The thickness of the shell is 70.7 mm which cannot be low because such a thin material will not be stiff and it will bulge out. Thus 80 mm thickness is optimum. 8.2. Thickness of head Empirical Constant (Cp) = 3.13 (Flat Head) Equivalent Diameter (De) = 920 mm = 92 cm (Assumed De = Di) Allowable stress (f) = 1300 kgf/cm2 = 1.2753 × 108 N/m2 Pressure (P) = 81.01336 kgf/cm2 = 8.05×106 N/m2 t = Cp × De ×
t = 3.13 × 92 ×
𝑃
(2)
𝑓 8.05×10 6 1.2753 × 10 8
t = 287.96 0.06312 = 72.3mm 8.3. Thickness of jacket Diameter of Jacket (Dj) = 92+7.07+7.07+7.23+7.23= 120.6 cm = 1206 mm Radius of Jacket (R) = 1206/2 = 603 mm Pressure (P) = 81.01336 kgf/cm2 Allowable Stress (f) = 1300 kgf/cm2 𝑃×𝑅
t = 𝑓𝐽 −0.6 𝑃
(3)
81.01336 ×603
t = 1300 ×0.8−0.6 × 81.01336 = 48972.6/991.39 = 49.4 mm Thus, the optimum thickness of the jacket is 5.0 cm. 16
8.4. Agitation calculations 8.4.1. Agitator thickness The empirical relations are: 𝐷𝑎 𝐷𝑡 𝐻 𝐷𝑡
1
≥3
(4)
~1
(5)
Where Da is the diameter of the agitator blade (40 cm), Dt is the internal diameter of the reactor (92 cm) and H is the height of the reactor (80 cm). For the given reactor: 𝐷𝑎 𝐷𝑡
40
1
= 92 = 0.43 ≥ 3
8.4.2. Agitator power calculations „n‟ is the number of the rotations of the agitator per minute (30 cycles/60 s), µ is the viscosity of the agitated fluid (0.90712 kg/m/sec) and KL (41) is the coefficient used for lower Reynolds‟s number. The agitator power is given in Eq. (6). P = KL n2 Da3 µ
(6) 40
P = 41 × (0.5)2 × (100 )3 × 0.90712 = 0.595 W = 595 mW. Therefore power consumed is 595 mW.
9. Digestion of SW with Aqua-Regia An aliquot of 0.2 g (to 1 mg) of powdered SW sample was taken in a silica crucible (150 mL). Then 9 mL of HCl (1M) was added and followed by 3 mL of HNO3 (1 M). The content of the crucible was carefully heated in a sand bath nearly to dryness in the fume hood. After cooling the crucible at room temperature 303.15 K (30 °C), dd-DI H2O was added to the sample, and then the content was filtered through a filter paper (Whatman No. 42). The filtrate was filled in a measuring flask and preserved for the determination of the dye and heavy metals as tCr adsorbed onto the surface of SW. 17
10. Preparation of BCP calibration series The pH of 1 mL of the solution that contains BCP dye was adjusted in a range 4.8-5.1 by adding 0.1M HCl. The color of the solution was greenish-yellow. The solution scanned by spectrophotometer to define the most favorable wavelength (λmax). A calibration series of BCP (0.01-0.09 mM) was established at the optimum pH and wavelength.
11. BCP absorption spectrum
Fig. S3. BCP chemical structure and its UV/VIS scan.
12. BCP calibration series The optimum linear range of BCP calibration series was obtained between 0.01-0.04 mM (Fig. S4) with r = 1 and the lower limit of detection (LOD) = 1.9 µM calculated as 3 × standard deviation (SD). The relative standard deviation (RSD) of the BCP standard solutions was less than 1% for n = 3, which suggests that the outcomes of the BCP measurements are very reproducible.
Table S2 Error assessment for BCP measurement.
18
Sample
Expected
Estimated
concentrations
No.
concentrations of BCP (n = 3) of BCP, µM
Conc.±SD, µM
Error, %
1
40
38.3±1.1
4.3
2
55
53.2±1.5
3.3
3
60
58.4±1.7
2.7
4
75
74.0±2.1
1.3
5
90
89.4±2.7
0.6
Fig. S4. Calibration series of BCP measured by the spectrophotometer.
13. Obstacles related to dye removal from the effluent of this industry and characterization of IWW It is difficult to remove organic materials from aqueous environment due to their prolonged destruction, easy release, and high treatment costs. Low efficiency of BCP dye removal (Bousnoubra et al., 2017), the need for special equipment, and the production of high volumes of sludge are regarded as the main disadvantages of the dye removal methods. The processes for fixing the criteria to determine the extent of contamination caused by textile industries are not defined in the Literature where we did not find a useful reference studied the pertinence contamination indices. 19
In the laboratory, after sample collection, the physiochemical analysis is performed on parameters such as pH, conductivity, temperature, turbidity, color, taste, odor, and other environmentally contaminating elements. Table S3 Target values (Mean±SD) of the physicochemical parameters of the IWW samples (n = 3) taken from the main effluent in the pond of the factory. Analyte
Before treatment(a)
WHO guidelines values
Color
Bluish gray
Clear
Density (kg/m3)
997.3±82.1
ND
Oil and grease (mg/L)
54.2±12.3
ND
Surface tension (mN/m) 72.6±8.50
ND
Temperature (K)
303.35±273.46
ND
Viscosity (kg/m/sec)
0.91±0.25
ND
BOD5 (mg/L)
226.8±4.3
50
COD (mg/L)
2138±30.3
1000
Color (Abs)
0.83±0.37
0.00
EC (mS/m)
137.6±1.82
100
DO (mg/L)
6.40±0.37
2-5
TDS (mg/L)
2283±24.8
2000
TSS (mg/L)
1146.6±15.4
220
Turbidity (NTU)
42.8±2.71
5.00
pH
8.92 ± 1.30
6.5-8.5
As (µg/L)
107.5±7.27
10.0
Cd (mg/L)
85.2±5.29
0.002
Co (µg/L)
98.1±17.4
1.00
20
Cr (mg/L)
19.8±1.20
0.01(b)
Cu (mg/L)
38.2±2.36
0.20
Fe (mg/L)
27.9±1.83
0.30
Hg (µg/L)
112.2±7.01
2.00 (c)
Mn (mg/L)
57.3±3.74
0.05
Ni (mg/L)
49.2±3.26
0.02
Pb (mg/L)
91.3±6.82
0.10
Zn (mg/L)
6.43±0.41
0.10
NH4+ (mg/L)
40.6±0.70
-
Cl- (mg/L)
278±15.70
4.00
NO3- (mg/L)
217.5±0.42
45
PO43- (mg/L)
107.4±0.16
12
SO42- (mg/L)
158.6±0.96
100
(a)
Biodegradability index (BI = BOD5/COD): 0.106±0.102
(b)
The actual environmental legislation: 0.5–2.5 mg/L for tCr, 0.1 mg/L
for Cr(VI) in industrial effluent, and 10 µg/L for tCr in drinking water (ATSDR, 2012); threshold limit for Cr(III) uptake in air is 0.1 mg/m3 (ATSDR, 2012); Chromium effect on human health: Damage to the nervous system, fatigue, and irritability (c)
More information about the toxicity behavior of Mercury can be
found in the research paper of Aljerf and AlMasri (2018) Note 1: The difference between TDS and TSS lies in the fact that, in TSS, the particles cannot pass through a filter with a 2-micron scale and remain suspended in the solution for an unknown period
21
Considering multiple threats and costs in this industry, the ranking of protection strategies depends on whether the multiple mutual threats are considered. So that an effective effort to identify and prioritize the extent of the greenness of textile production industries is exigent, which as a result, can present a solution to enhance the greenness of dye supply chain. Table S3 refers to the necessity to the maximization of return on investment in outflow water conservation in order to protect aquatic biodiversity (Aljerf, 2017). Therefore, IWW must be made compatible with the health of ecosystems to coordinate the measures for labors and lifestyle in the adjacent area of the industrial facilities.
14. Characterization of SW The properties of the SW are provided in Table S4. Table S4 Some parameters of the SW samples (N = 36, n = 3) taken from the pond of the factory. LHV(d)
Proximate analysis (air dry basis), % Volatiles
Fixed
Ash
Moisture
MJ/kg
42.4±11.3
3.71±0.85
13.8±3.29
carbon 44.5±8.42 9.39±1.04 (d)
Lower heating value (LHV)
22
15. BCP distributions in IWW and SW Table S5 The effect of dyeing practices on BCP contents in IWW and SW (n = 3). Dyeing practice
BCP (Conc.±SD, µM) in IWW
BCP (Conc.±SD, µg/kg) in SW
Sample 1
20.8±0.56
662.4±75.1
Sample 2
21.6±0.57
674.9 ±76.2
Sample 3
22.4±0.57
691.8±78.3
Sample 4
22.4±0.58
703.1±80.0
Var.
0.590
323.8
Package Dyeing
Standard
error 0.383
9.00
(SE) CV (%)
3.48
2.60
Skewness
-0.43
-0.04
Sample 1
29.6±0.81
922.3±106.7
Sample 2
30.2±0.83
951.8±108.1
Sample 3
31.3±0.86
996.4±112.8
Sample 4
32.7±0.90
1011.0±114.9
Var.
1.86
1661.3
SE
0.681
20.4
CV (%)
4.39
4.21
Skewness
0.33
-0.16
Jet Dyeing
Garment Dyeing 23
Sample 1
36.5±1.00
1162.4±131.8
Sample 2
36.8±1.00
1172.0±132.9
Sample 3
37.4±1.02
1191.1±135.1
Sample 4
37.9±1.04
1205.0±136.3
Var.
0.390
364.8
SE
0.312
9.50
CV (%)
1.68
1.53
Skewness
0.16
0.11
Sample 1
47.6±1.31
1518.2±172.9
Sample 2
48.9±1.34
1557.3±175.6
Sample 3
49.1±1.35
1561.6±176.3
Sample 4
49.3±1.35
1570.1±178.0
Var.
0.589
530.0
SE
0.384
11.5
CV (%)
1.52
1.46
Skewness
-0.87
-0.84
Sample 1
65.2±1.78
2076.8±234.7
Sample 2
65.5±1.79
2089.1±236.0
Sample 3
66.3±1.81
2109.3±239.4
Sample 4
67.8±1.85
2143.2±244.6
Var.
1.35
841.8
SE
0.582
14.5
Beam Dyeing
Pad Dyeing
24
CV (%)
1.77
1.40
Skewness
0.58
0.44
Sample 1
70.8±1.93
2258.2±255.6
Sample 2
71.3±1.94
2266.7±257.4
Sample 3
72.6±1.98
2312.4±259.1
Sample 4
74.2±2.01
2363.0±262.9
Var.
2.31
2326.3
SE
0.760
24.0
CV (%)
2.09
2.03
Skewness
0.39
0.42
Sample 1
83.5±2.26
2659.2±301.5
Sample 2
83.9±2.27
2681.9±302.7
Sample 3
84.6±2.90
2694.2± 302.9
Sample 4
84.6±3.91
2696.2±303.4
Var.
0.297
289.1
SE
0.272
8.47
CV (%)
0.58
0.46
Skewness
-0.22
-0.64
Sample 1
86.2±3.98
2738.1±309.2
Sample 2
86.7±4.00
2751.9±311.0
Jig Dyeing
Skein Dyeing
Stock
and
Top
Dyeing
25
Sample 3
86.9±4.01
2767.4±313.8
Sample 4
87.0±4.02
2770.6±314.1
Var.
0.127
225.4
SE
0.178
7.46
CV (%)
0.41
0.45
Skewness
-0.67
-0.32
Sample 1
89.5±4.13
2844.5±321.4
Sample 2
89.7±4.14
2852.0±323.9
Sample 3
90.3±4.17
2869.7±326.0
Sample 4
90.5±4.17
2881.2±326.8
Var.
0.227
278.0
SE
0.238
8.27
CV (%)
0.52
0.62
Skewness
0.00
0.11
Net quantity
60.0±24.7
1899.4±790.0
Yarn Dyeing
Statistical analysis was performed by Microcal Origin (V. 6.0) software
26
16. Characterization of the modified adsorbent (CL-SW) surface Table S6 Summary of pore size (dp), BET surface area (SA) of pores (m2/g), pore volume (Vp), and surface aspect of the modified surface at room temperature (N = 36, n = 3). Physical
SA (m2/g)
Vp (cm3/g)
Surface aspect
50.0±0.8 At P/P° =
1.24±0.03
Heterogeneous
dp (nm)
technique Adsorption (by BET)
0.61±0.01;
with mesopores
SBET: 1918.6±33 Adsorption cumulative Desorption
43.3±0.7 256.0±4.4
0.31±0.01
38.6±0.7 276.6±4.8 0.31±0.01
P/P° is the relative pressure : saturation pressure (Lowell et al., 2004; Aljerf and Choukaife, 2015); Water hold (n = 9): 62.8±3.52% (w/w) The higher SA found is beneficial for physisorption process.
17. Liquid to solid (L/S) ratio One of the key factors that influence the desorption process is the liquid to solid ratio (L/S), which is the amount of eluting solution used (L) for the mass of loaded sorbent (g). L/S ratio needs to be preferably low for economic reasons (L/S = 3) that increases desorption ratio (84%). But, for tCr loadings, a higher L/S ratio (7) using a small volume of NH 3 results in a higher tCr concentration (97.6%) desorbed from the solution if desorption efficiency
27
remains constant. Therefore, desorption ratio (D %) has increased with increasing L/S ratio as qdes also increases due to high tCr concentrations released into the eluate.
18. S/N ratio The experimental designs consist of a small number of orthogonal arrays (combination of control and noise factors), selected based on the number of factors (variables) and levels (states).This approach recommends transformation of collected data into signal-to-noise (S/N) ratio, which is a measure of response variations and a performance parameter that helps to measure the sensitivity of quality deviating from the measured values (Djurić et al., 2016). S/N ratio is also the log transformation of mean square deviation of desired response, where the signal (S) is the desirable effect (mean) and noise (N) is the undesirable effect (signal disturbance) (Djurić et al., 2016). An appropriate ratio must be chosen depending on criteria such as smaller-is-better, larger-is-better, and nominal-is-better. The S/N ratio is calculated by Eq. (7). 𝑆 𝑁
1
= −10 log10 [𝑛
1 𝑛 𝑖=1 𝑦 2 ]
(7)
𝑖
yi being the response variable for n observations.
19. Kinetic rate equations The experimental data of the kinetic study are usually used to elucidate a variety of kinetic adsorption models including Pseudo-first-order (PFO), Pseudo-second-order (PSO), Elovich, Avrami, General order and diffusion models namely “Intra-particle diffusion”, Crank long time (Boyd), Vermeulen, Bangham and Linear film diffusion. Between these, Pseudo-first-order and pseudo-second-order models have been widely used to describe the sorption kinetic process. These originally empirical models can be expressed by the following linear forms presented in Table S7. 28
Table S7 Lists of kinetic rate equations used in the present work. Kinetic equations
Linear form
Pseudo-first order
1 log (𝑞𝑒 -𝑞𝑡 ) = log 𝑞𝑒 - 2.303
Pseudo-second order
𝑘 𝑡
𝑡 𝑞𝑡
1
=𝑞 t+𝑘 𝑒
1 2 2 .𝑞 𝑡
Plot
Ref.
log (𝑞𝑒 -𝑞𝑡 ) vs. t
(Lagergren, 1907)
𝑡
(Ho and McKay,
𝑞𝑡
vs. t
1999) Intra-particle
𝑞𝑡 vs. t1/2
𝑞𝑡 = 𝐾𝑖 𝑡 + I
diffusion
(Kasten
et
al.,
1952)
Where k1, k2, Ki are the pseudo-first, second-order rate constants, and intra-particle diffusion rate (mg/g/min1/2), respectively. Besides, qe and qt are the solid-phase concentrations of the metal desorbed at any time t and equilibrium. I value is the intercept, where the larger the intercept value, the greater is the boundary layer effect and hence, the greater is the surface sorption contribution in the rate controlling step. The third model equation establishes a linear regression relationship between adsorption or sorption capacity and the square root of time. In general, the straight line obtained from the plots suggests the applicability of the kinetic models to fit the experimental data.
20. Adsorption activation energy (𝑬𝒂 ) Using rate constant (k2) at three different temperatures, the ln k2 versus 1/T plots as per Arrhenius is viewed in Eq. (8). 𝐸
ln 𝑘2 = − 2.303𝑎 𝑅𝑇 + 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
(8)
29
21. Adsorption isotherm models Adsorption equilibrium is usually described by an isotherm equation whose parameters express the surface properties and affinity of a solute on an adsorbent. Adsorption isotherms (Table S8) can be described by various models, of which the Langmuir and Freundlich models are the most commonly used (Unuabonah et al., 2008; Aljerf and Choukaife; 2015). 21.1. Langmuir Langmuir model (Langmuir, 1916) was first introduced to investigate gas adsorption on a solid material (activated carbon (AC)), is now widely used to examine the adsorption of adsorbate in aqueous medium on the surface of the solid adsorbent. Furthermore, the Langmuir model assumes that adsorption of molecules occurs on a surface of adsorbent at a fixed temperature, forming a monolayer without any interaction between molecules adsorbed on the surface. Good adsorbents are those that have a high maximum adsorption capacity (qmax, mg/g) in a monolayer and low constant related to the energy of adsorption (b, L/mg) value. This experimental model considers single layer adsorption. Based on the formula of this isotherm model, the adsorbate initially bonds adsorbent by physical forces, and all adsorption sites have the same tendencies to be adsorbed onto the solid adsorbent surface. Further, each molecule includes constant enthalpy (ΔH°) and Ea. 21.2. Freundlich Freundlich‟s equation (Freundlich, 1906) is used to describe the adsorption of solute on a heterogeneous surface. In specific, Freundlich isotherms describe a non-ideal and reversible mechanism in which occurs a multilayer adsorption onto heterogeneous surface active sites. The Freundlich linear function is graphically expressed as log qe vs.log Ce, in which the slope equals to 1/n and the intersection with y-axis equals to log 𝑘𝑓 . Where 𝑘𝑓 is the Freundlich adsorption equilibrium constant that is positively linked with the adsorption
30
capacity of the adsorbent (mg/g); n stands for the constant of adsorption intensity in which values greater than 1 indicates efficient adsorbents. The range of 1/n values at the interval of 0-1 is a criterion of adsorption intensity and non-uniform surface. An increase takes place in the non-uniformity if its value converges to zero. 1/n values lower than 1 indicates chemical adsorption, while cooperative adsorption is considered for values higher than 1. For instance, based on Table 8 in the main text, 1/n values are lower than 1, which refers to the chemical adsorption type of tCr on the modified surface. 21.3. Temkin The equation and the linearized form of Temkin equilibrium isotherm model were represented by plotting qe vs. ln Ce (Yang, 1993). Where b is the Temkin constant related to the heat of adsorption (J/mol), Kt Temkin constant (L/mg), R is the gas constant (8.314 J/mol K) and T is absolute temperature (K). 21.4. Langmuir-Freundlich (Sips) Sips isotherm (Sips, 1950) is a three-parameter isotherm model, a combined form of Freundlich and Langmuir isotherms, which is normally applied to examine heterogeneous adsorption and local adsorption process without any reaction between adsorbent and adsorbate. Sips isotherm (KS (L/mg), n: Sips isotherm constant, and qs: maximum adsorption capacity (mg/g)) is reduced in low concentrations of adsorbate to two-parameter Freundlich isotherm, which predicts the single-layer adsorption capacity of Langmuir isotherm in high concentrations of adsorbate.
31
Table S8 List of adsorption isotherm models used in the present work. Isotherm Langmuir
Linear form 𝑐𝑒 𝑞𝑒
= 𝑏𝑞
1 𝑚𝑎𝑥
t+𝑞
Plot
Ref.
𝑐𝑒
𝑐𝑒
(Langmuir, 1916)
𝑚𝑎𝑥
𝑞𝑒
vs. 𝑐𝑒
Freundlich
1 log (𝑞𝑒 ) = log 𝑘𝑓 + 𝑛 log 𝑐𝑒 log (𝑞𝑒 ) vs. log 𝑐𝑒
Temkin
𝑞𝑒 =
𝑅𝑇 𝑏
ln 𝐶𝑒 +
𝑅𝑇 𝑏
ln 𝑘𝑡
Langmuir-
(Freundlich, 1906)
𝑞𝑒 vs. ln 𝑐𝑒
(Yang, 1993)
𝑞𝑒 vs. 𝑐𝑒
(Sips, 1950)
𝒏
Freundlich (Sips) 𝒒𝒆 = 𝒒𝒔𝒌𝒔 𝑪𝒆 𝒏 𝟏+𝒌 𝑪 𝒔 𝒆
21.5. Isothermal parameters of BCP adsorption The fitted parameters of each isothermal model are shown in Table S9. Regarding BCP adsorption onto the CL modified adsorbent, the best fitting model was Langmuir, followed by Freundlich and Temkin. From this Table, it can be concluded that the Langmuir isotherm fitted the experimental data, which suggests that the adsorption of BCP molecules was represented well by a monolayer adsorption model (Langmuir, 1916). Langmuir adsorption isotherm assumes that the adsorption takes place at specific homogenous sites of the modified surface of CL and that the adsorbed layer is one molecule thick, as once these molecules occupy the vacant locations, so no further adsorption can take place at these sites. Moreover, it assumes that the adsorption energy is constant which does not depend on the degree of occupation of the active centers of adsorbent. In addition, Langmuir model considers that all adsorbent sites are identical and energetically equivalent and there is no interaction between molecules adsorbed on neighboring sites.
32
Table S9 Isothermal parameters of the adsorption of the dye on the CL and the CL-SW. Adsorption model
Adsorbent surface CL
qmax (mg/g)
CL-SW
x̅(e)
SD(e) x̅(e)
SD(e)
2.42
0.76
2.09
83.7
Langmuir b (L/mg)
1.23
0.013
r(f)
0.841
0.992
χ2
0.110
0.007
Freundlich KF (mg/g) (L/mg)1/n
1.20
1/n
0.46
5.96
1.04
0.03
0.35
0.00
r(f)
0.833
0.980
χ2
0.402
0.156
Temkin KT (L/mg)
0.06
b (J/mol)
32.8
180
R(g)
0.743
0.875
χ2
0.323
0.212
(e)
0.00
0.15
0.00
x̅: mean value, SD: standard deviation, χ2:
Pearson‟s chi-squared (f)
Correlation coefficient is statistically significant
using t-test at 95% confidence level (g)
Correlation coefficient is statistically significant
using t-test at 90% confidence level
33
22. Thermodynamic study For better understanding of the effect of temperature on the adsorption, it is important to study the thermodynamic parameters such as standard Gibbs free energy change (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°). These parameters refer to the spontaneity and exothermicity or endothermicity of adsorption process on the adsorbent. The Gibbs free energy adsorption using adsorption equilibrium constant (Kc) is calculated from Eq. (9). ΔG° = - 2.0303 RT log KC
(9)
ΔH° and ΔS° of adsorption are estimated from van‟t Hoff equation (Eq. (10)). ΔSo
ΔHo
log Kc = 2.303R − 2.303RT
(10)
R is the gas constant and Kc is the equilibrium constant which can be calculated from Eq. (11). Kc =
Ce
(11)
qe
Ce is the equilibrium concentration of the dye or heavy metals as Cr ions in the solution (mg/L) and qe is the extent of dye molecules or Cr ions adsorbed per mass unit of adsorbent (mg/g). The plot of log Kc against 1/T (in Kelvin) should be linear. The slope of the van‟t Hoff plot is equal to -ΔH°/2.303 R, and its intercept is equal to ΔS°/2.303 R.
23. Theoretical assessment of the adsorption capacity and percent removal of BCP dye The quantity adsorbed by a unit mass of an adsorbent at equilibrium (qe) and the adsorption percentage (R, %) at an instant were calculated using Eq. (12) and Eq. (13), respectively, qe =
𝐶0 −𝐶𝑒 𝑚
× 𝑉
(12) 34
R (%) =
𝐶0 −𝐶𝑡 𝐶0
× 100
(13)
Where Ct is the concentration of adsorbate at time t; Co is the initial concentration of adsorbate; Ce is the concentration of adsorbate at equilibrium; m (g) is the mass of the adsorbent; V is the volume of the adsorbate solution. 23.1. Application (dye adsorption) Co = 11.7±0.30 mg/L (22.4±0.58 µM) Ct = 1.10±0.03 mg/L (2.29±0.06 µM) m (adsorbent) = 0.0604 g (±0.1 mg) V= 1 L From Eq. (12): qe =
11.7−1.1
×1
0.0604
qe = 175.5 mg/g From Eq. (13): R (%) = R=
𝐶0 −𝐶𝑡 𝐶0
11.7−1.1 11.7
× 100
× 100
R = 90.6%
24. Zeta potential The zeta potential was determined with various concentrations of BCP (25-90 µM) diluted with preprepared salt solutions (50-550 mM KCl), plotted in Fig. S5 and the calculated parameters of the adsorbent‟s surface properties were listed in Table S10.
35
Fig. S5. Zeta potential distribution at various ionic strengths. The zeta potential value increases from slightly negative charged of -3.00 to -15.00 mV, indicating that BCP has modified the surface charge distribution and provides more negative charge and thus giving electrostatic repulsion which improve the stability and transport properties. Noticeably, as the BCP concentration increases, the adsorbed layer thickness nonlinearly increases and this is in consistent with the conceptual model in which the adsorbed electrolyte layer is in flat conformation (trains) at low adsorbed mass. However, at higher adsorbed mass, the fraction of loops and tails increases, exhibiting more extended layer conformation. Herein, the results indicate that BCP adsorbed layer thickness is affected by BCP concentration.
36
Table S10 Surface properties of the adsorbent and the characterization of the adsorptive layer‟s stability and reactivity at different additions of BCP dye (N = 36, n = 3). BCP
Diameter, Charge
(µM) (d50, nm)
Softness
Layer
Characteristic
Reaction
density (ρ,
(λ, ×108
thickness
time (τ, min)
rate
mol/m3)
m-1)
(d, nm) -
constant (k, min-1)
0
4.20±0.10 -
-
5.06
-0.1086
25
51.8±1.24 0.11±0.02
0.25±0.02 2.90±0.23 7.45
-0.0164
50
33.6±0.79 0.16±0.02
0.34±0.05 3.35±0.41 18.2
-0.0922
75
38.5±0.88 0.18±0.03
0.38±0.02 5.76±0.48 47.8
-0.0569
90
53.0±1.25 0.19±0.03
0.36±0.06 6.19±0.66 58.0
-0.0393
25. Impact of ionic strength Ionic strength impact on pollution removal is an important parameter. Because IWW (rich with dyes) contains also different salts and various metal ions, the presence of these ions causes an increasing of ionic strength. In this study, the influence of four common metal ions (Na+, K+, Ca2+, and Mg2+) on BCP adsorption in 30 mL solution contains 90 µM BCP at pH = 6.5 was investigated. Fig. S6 shows that salts (Conc. 0.1 M) and metal ions are adsorbed onto the CL as competitors, leading to decrease of BCP adsorption capacity. This decrease is more significant for ions with two positive charges (Ca2+ and Mg2+). According to the negative charge of the CL adsorbent, the attraction of more positive charges is strong. The interfering effect of Mg2+ can be eliminated for tCr adsorption at higher pH values (alkaline phase) because Mg2+ ions precipitate in this medium.
37
Fig. S6. Effect of different salts on BCP adsorption on CL (percent denotes to dye removal).
26. Comparative study of BCP dye adsorption capacity (mg/g) and its removal (%) with previous studies used zeolite as adsorbent The current adsorbent capacity of dye adsorption was compared with those of other adsorbents. Table S11 shows the results. Experimental conditions including qe and dye removal (%) for each adsorbent are listed in this Table.
38
Table S11 Comparative study of adsorption capacity and dye removal of BCP adsorbed onto the modified CL surface with previous studies employed CL as an adsorbent for other dyes. Dye
CI Reactive Black 5 (azo)
Adsorbent
CL
qe
Dye removal Ref.
(mg/g)
(%)
61
ND
(Armaǧan et al., 2003)
CI Reactive Yellow 176 (azo)
CL
89
ND
(Armaǧan et al., 2003)
CI Reactive Red 239 (azo)
CL
111
ND
(Armaǧan et al., 2003)
Everzol Yellow 3RS H/C (azo)
CL
7.6
35
(Armaǧan et al., 2004)
Methylene blue (MB)
Zeolite
35.4
ND
(FA-ZX) BCP
CL-SW
(Wang
et
al.,
2009) 175.5
90.6
Current study
As shown, dye adsorption capacity of the modified adsorbent in the present study is higher than other competitive adsorbents and the adsorbents‟ surface is covered with dye molecules. Thus, it is concluded that this surface can perform well in dye adsorption.
39
27. Analytical conditions for tCr measurement by direct flame atomic absorption spectroscopy (FL-AAS) Table S12 Instrumental conditions for tCr determination by FL-AAS. Parameter
Condition
Background correction
D2 lamp
Elution flow rate (mL/min)
2.9
Enhancement factor
50
Flame
N2O – Air
Loading time (s)
60
Measurement mode
Peak area/height
Modifier
2% (w/v) NH4Cl
Relative noise
1.0
Sampling frequency (1/h)
15
Spectral bandwidth (nm)
0.7
Wavelength (nm)
357.9
40
28. tCr calibration series by FL-AAS
Fig. S7. Calibration series of tCr measured by FL-AAS (n = 3).
29. Analytical performance for tCr measurement by FL-AAS The precision of the FL-AAS method was evaluated using IWW samples spiked with 100 µgtCr/L. To ensure accuracy, reliability and reproducibility of data, the experiments were carried out in triplicate (except the recovery) and the relative error did not exceed ± 0.03 (Table S13). Table S13 Analytical performance for tCr measurement by FL-AAS. Analytical parameter
Value
Linear range (mg/L) (n = 3)
0.45-1.20
LOD (µg/L) (n = 3)
0.6
LOQ (µg/L) (n = 3)
2.0
RSD (%) (n = 3)
1.92
Recovery ± RSD (%) (n = 9) (h)
98.6±2.70
(h)
Recoveries of tCr in IWW at 100 µg/L spiked level. 41
As we can see from Table S13, the recovery of the spiked tCr and the relative standard deviation (RSD) were agreeable found, suggesting the satisfactory accuracy and application prospect of the established method.
30. tCr distributions in IWW and SW Table S14 The effect of dyeing practices on tCr contents in IWW and SW (n = 3). Dyeing practice
tCr (Conc.±SD, mg/L) tCr (Conc.±SD, mg/kg) in IWW
in SW
Package Dyeing Sample 1
4.90±0.30
3.00±0.34
Sample 2
5.00±0.31
3.10±0.34
Sample 3
5.20±0.32
3.10±0.35
Sample 4
5.20±0.32
3.40±0.37
Var.
0.023
0.022
SE
0.075
0.087
CV (%)
3.00
5.50
Skewness
-0.19
0.77
Sample 1
6.00±0.37
3.70±0.40
Sample 2
6.00±0.38
3.70±0.40
Sample 3
6.20±0.38
3.70±0.40
Sample 4
6.40±0.39
4.00±0.43
Var.
0.037
0.017
Jet Dyeing
42
SE
0.096
0.075
CV (%)
3.10
4.00
Skewness
0.43
1.00
Sample 1
7.20±0.43
4.50±0.49
Sample 2
7.60±0.47
4.70±0.51
Sample 3
7.70±0.48
4.80±0.52
Sample 4
7.70±0.48
5.00±0.54
Var.
0.057
0.032
SE
0.119
0.104
CV (%)
3.20
4.40
Skewness
-0.89
0.00
Sample 1
12.9±0.75
7.90±0.86
Sample 2
13.2±0.81
8.00±0.87
Sample 3
13.3±0.81
8.20±0.89
Sample 4
13.3±0.82
8.20±0.89
Var.
0.036
0.017
SE
0.095
0.075
CV (%)
1.40
1.90
Skewness
-0.83
-0.19
Sample 1
15.8±0.97
9.70±1.05
Sample 2
15.9±0.98
9.80±1.07
Garment Dyeing
Beam Dyeing
Pad Dyeing
43
Sample 3
15.9±0.98
9.80±1.07
Sample 4
16.2±1.00
10.0±1.09
Var.
0.030
0.012
SE
0.087
0.063
CV (%)
1.10
1.30
Skewness
0.77
0.56
Sample 1
18.4±1.12
11.3±1.23
Sample 2
18.6±1.13
11.5±1.25
Sample 3
18.6±1.13
11.5±1.25
Sample 4
18.8±1.14
11.6±1.26
Var.
0.027
0.012
SE
0.082
0.063
CV (%)
0.90
1.10
Skewness
0.00
-0.56
Sample 1
20.5±1.24
12.7±1.38
Sample 2
20.6±1.24
12.7±1.38
Sample 3
20.6±1.25
12.7±1.39
Sample 4
20.7±1.25
12.8±1.40
Var.
0.007
0.002
SE
0.041
0.025
CV (%)
0.40
0.40
Skewness
0.00
1.00
Jig Dyeing
Skein Dyeing
44
Stock and Top Dyeing Sample 1
23.5±1.42
14.5±1.58
Sample 2
23.5±1.42
14.5±1.59
Sample 3
23.6±1.43
14.6±1.59
Sample 4
23.6±1.43
14.6±1.60
Var.
0.003
0.003
SE
0.029
0.029
CV (%)
0.20
0.40
Skewness
0.00
0.00
Sample 1
24.0±1.46
14.8±1.61
Sample 2
24.3±1.48
15.1±1.63
Sample 3
24.4±1.48
15.1±1.64
Sample 4
24.5±1.49
15.2±1.66
Var.
0.047
0.030
SE
0.108
0.087
CV (%)
0.90
1.20
Skewness
-0.60
-0.77
Net quantity
15.0±7.10
9.26±4.38
Yarn Dyeing
Statistical analysis was performed by Microcal Origin (V. 6.0) software
31. IR characterization of the modified adsorbent The surface properties of the sorbents are very important for the sorption of heavy metal ions. Therefore, the samples were characterized by FTIR analysis. Nicolet iS 10 spectrometer from Thermo Scientific was used to evaluate the main functional groups likely responsible 45
for tCr adsorption. The FTIR spectra were obtained using the Attenuated Total Reflection (ATR) mode coupled with a germanium (Ge) crystal. The ground and sieved samples were analyzed in the range of 500 to 4000 cm1-. Fig. S8 described the functional groups which exist in the modified adsorbent. The broadband at 3276–3500 cm1- shows the presence of free and intermolecular bonded –OH and the stretching vibration of –NH groups due to the treatment in the ammoniac phase. The adsorption of Cr occurs at range 3276–3500 cm1-. Group of hydroxyls (O−H stretching vibration) at 3421.10 cm1- were intensified and widened greatly, overlapping the absorption peaks of −CH2 groups (possibly originated during the dye adsorption) at 2923 and 2852 cm1-. The O−H stretching vibration was shifted to 3424.46 cm1. The second hydroxyl band was absorbed in 1376 cm1-, which can be attributed to O−H bending vibration. The bands around 1050 cm1- are related to the C–O stretching vibrations. The adsorption of Cr also occurs on the overlapped peaks of -SO3- and C-O carbonyl groups which are shifted from 1734.16 cm1- to 1735.49 cm1-. The intensities of these peaks decrease in FTIR spectra before and after sorption of Cr. Thus, these acidic surface oxygen functional groups are the major factors that significantly have impacts on the chemical sorption reactions like ion exchange. Furthermore, the intensity of absorption bands between 1700 and 1000 cm1- decreased as shown in FTIR spectra of the adsorbent before and after sorption of Cr. The presence of C=O is indicated by the peak at 1735 cm1-. About 2850-2950 cm1-, the peaks are attributed to C-H bonds connected to the carbonyl group. C-H stretching group at 2923.73 cm1- was shifted to 2922.42 cm1-. The shifting on some functional groups indicated the occurrence of Cr adsorption. As a result, FTIR spectrum of the modified adsorbent after Cr adsorption in fingerprint site indicates the presence of adsorbate in adsorbent structure.
46
Fig. S8. FTIR spectrum of the modified surface in the ammoniac phase (a) before and (b) after tCr adsorption (Background correction of spectra was performed by 16 scans with a resolution of 2 cm1-).
32. Cr (III) distribution species with pH change pH solution plays an important role in metal ions sorption process. Generally, pH solution influences the surface charge of the sorbents and the existing form of the heavy metal ions. Therefore, the distribution species in tannery wastewater for pH scale [0-12] is illustrated in Fig. S9.
47
Fig. S9. Speciation diagram for Cr(III) complexes present in aqueous solution. Adapted from Fahim et al. (2006).
33. Cr nature in the alkaline medium The higher pH (˃9.00) values were not employed to avoid metal hydroxide precipitation thereby leading to enormous values for adsorption capacities of the modified surface. However, with the increase of pH solution (7˂ pH ˂9), both the deprotonation process and the weak competition of H+ cause the increase of tCr sorption onto the sorbents. In general, we anticipate that at higher pH values, the decrease in the H+ concentration and the increase in the negative charge density onto the modified surface encourage the adsorption of heavy metal ions as we will see later.
Fig. S10. Octahedral complexes of Cr(III) ligands in alkaline medium. 48
Table S15 Hydrolysis species and constants of Cr(III) (Gray and Matijević, 1987). Equation
Log ki(h)
Cr3++H2O↔CrOH2++H+
-4.0
Cr3++2H2O↔Cr(OH)2++2H+
-9.7
Cr3++3H2O↔Cr(OH)3+3H+
-18.0
2Cr3++2H2O↔Cr2(OH)24++2H+ -5.0 3Cr3++4H2O↔Cr3(OH)45++4H+ -8.2 Cr3++4H2O↔Cr(OH)4-+4H+ (h)
-27.4
ki: binding constant.
34. Effect of agitation rate Fig. S11 explained that adsorption capacity of the modified surface had increased as the agitation rate rose until equilibrium attained. Cr had maximum adsorption capacity 37.5 mg/g at 150 rpm. Agitation speed affected by the adsorbent and adsorbed interaction. At the initial stage, minimum adsorption capacity occurred due to accumulating of adsorbent at the bottom of the Erlenmeyer flask. Meanwhile, when the agitation speed increased from 150 rpm to 250 rpm, adsorption capacity decreased since the adsorbent and adsorbate could not interact properly and the metal ions that have been adsorbed onto the active site released to the liquid phase. As consequence of the agitation experiment, the boundary layer around adsorbent was broken, this provided interaction of metal ions and active site.
49
Fig. S11. Effect of agitation rate on Cr-adsorption onto the modified surface (pH 8.8, contact time 55 min, initial concentration 16 mg/L, and mass of adsorbent 0.4 g).
35. Separation factors The essential characteristics of the Langmuir isotherm are expressed in terms of a dimensionless constant commonly known as separation factor, KL. The adsorption mechanism can be assessed as unfavorable (KL > 1), linear (KL = 1), and favorable (0 < KL < 1) or irreversible (KL = 0). 35.1.
For dye 1
KL = 1+b 𝐶
(14)
0
𝟏
KL = 𝟏+𝟎.𝟎𝟏𝟑×𝟏𝟏.𝟕 KL = 0.87 So that adsorption process occurs normally under tested conditions.
50
35.2. For tCr From Eq. (14): 1
KL = 1+1.9×16.0 KL = 0.03 So that adsorption process occurs normally under tested conditions.
36. Theoretical assessment of the adsorption capacity and percent removal of tCr Under the optimum conditions (dose of CL-SW-BCP adsorbent (m) = 0.4 g (± 0.1 mg), pH 8.8, equilibrium time (t) = 55 min and volume of solution (V) = 950 mL), the quantity of Cr adsorbed onto the modified surface had been calculated from Eq. (12), where: Co = 16.0±0.98 mgCr/L (307.7±18.8 µM Cr) and Ct = 0.38±0.00 mgCr/L (7.31±0.00 µM Cr) have been analyzed by graphite furnace-atomic absorption spectroscopy (GF-AAS). qe =
16−0.38 0.4
× 0.95
qe = 37 mg/g The adsorption percentage (R, %) of Cr at an instant was calculated using Eq. (13), as follows, R=
16−0.38 16
× 100
R = 97.6%
37. X-ray photoelectron spectroscopy analysis Cr metallic state incorporated in CL structure was further examined by XPS and the spectra are provided in Fig. S12. Cr peaks were obviously observed from the wide-scan spectra of the modified surface (Fig. S12-A), indicating the successful loading of Cr on the modified surface. Detailed spectra of Cr are presented in Fig. S12-B. The Cr 2p3/2 peak at
51
642.1 ev and the Cr 2p1/2 peak at 653.6 ev were observed. The separation of 11.5 ev indicates Cr exhibited oxidation state between Cr3+ and Cr6+. Also, it can be seen that Cr3+ was predominant from Cr 2p3/2 peak. The O 1s spectra from original CL adsorbent and the modified adsorbent were shown in Fig. S12-C and D. The peak at 533.5 ev can be assigned to surface adsorbed oxygen in the form of Cr-O-. The peak at around 531.5 ev can be attributed to the hydroxyl groups of CL bonding to Cr (Cr-OH) or C (C-OH) on the CL. Obviously, O 1s spectra for the modified surface showed a new peak at 530.0 ev, which is generally accepted as lattice oxygen in the form of O2- (Cr-O). So, XPS analysis confirms the existence of Cr bonding with the oxygen of dye adsorbed on the modified CL surface.
Fig. S12. XPS spectra of the samples. (A) XPS wide scan of the CL and the modified surface, (B) O1s in the modified surface, (C) O1s in CL, and (D) Cr2p in the modified surface.
52
38. Effect of coexisting metal ions Ca2+ ions are the ubiquitous alkaline-earth metal cations in natural water or wastewater. In this study, Ca2+ ions were selected as the model co-cations to evaluate the sorption selectivity of the sorbent and the modified sorbent to Cr3+. As shown in Fig. S13, co-existing Ca2+ had little influence on Cr3+ sorption onto the modified surface, even the concentration of Ca2+ amounted to 50 times higher than that of Cr3+. The original surface of the sorbent (CL) also showed certain selectivity to Cr3+ and only 10% reduction was observed at Ca2+/ Cr3+ = 50. The high selectivity of the original surface (CL) and the modified surface can be attributed to the fact that Cr3+ had a much higher affinity to the functional groups on the surface of the sorbents than that of Ca2+. The excellent anti-interference ability of the modified sorbent indicates its great potential that can be applied in real industrial wastewater treatment plants.
Fig. S13. Influence of Ca2+ on Cr3+ sorption by both CL surface and the modified surface.
53
39. Biodegradability The BOD5 and COD were compared between the influent and effluent at different dyeing processes (Table S16). Table S16 The effect of IWW treatment with CL-SW on BOD5 and COD (n = 5). Dyeing practice
Before treatment BOD5
COD
(mg/L)
(mg/L)
Package Dyeing
110.3±2.09
568.5±8.13
Jet Dyeing
121.2±2.26
Garment
After treatment BI
BOD5
COD
BI
(mg/L)
(mg/L)
0.194
1.28±0.01
4.41±0.06
0.290
644.9±9.20
0.188
1.42±0.02
5.07±0.07
0.280
141.0±2.64
762.4±10.7
0.185
1.71±0.03
6.11±0.09
0.280
Beam Dyeing
149.1±2.81
828.2±11.8
0.180
1.83±0.03
6.78±0.10
0.270
Pad Dyeing
178.7±3.37
1015.3±14.4 0.176
2.19±0.03
8.11±0.14
0.270
Jig Dyeing
213.6±4.05
1315.7±18.5 0.162
3.27±0.05
12.6±0.19
0.256
Skein Dyeing
220.1±4.17
1494.1±21.3 0.147
3.42±0.06
13.2±0.20
0.259
Stock and Top
234.9±4.45
1998.4±28.6 0.118
4.75±0.08
19.0±0.28
0.250
239.8±4.57
2215.8±31.4 0.108
5.21±0.09
21.7±0.31
0.240
Dyeing
Dyeing Yarn Dyeing
IWW volume: 10.0 L, Flow rate: 30 mL/min, service time ≥ 12 h, and 303.15 K
40. Suitability for irrigation of the industrial wastewater after treatment The classification of irrigation water according to the residual sodium carbonate (RSC) values is such that waters containing more than 2.5 meq/L of RSC are not suitable for irrigation, while those having 1 to 2.5 meq/L are doubtful and those from 0 – 1 meq/L are 54
good for irrigation (Eaton, 1950). RSC has been calculated to determine the hazardous effect of carbonate (CO32-) and bicarbonate (HCO3-) on the quality of the generated water after treatment for agricultural purpose using Eq. (15). RSC = ([CO32-] + [HCO3-]) – ([Ca2+] + [Mg2+])
(15)
All ionic concentrations are expressed as meq/L (USEPA method 300.0, 1993). The classification of irrigation water according to the RSC values is such that waters containing more than 2.5 meq/L RSC are not suitable for irrigation, while those having 1 to 2.5 meq/L are marginal and those from 0 –1 meq/L are good for irrigation (Eaton, 1950). Moreover, World Health Organization (WHO) (WHO, 1989) uses another criterion for assessing the suitability of water for irrigation based on the permeability index (PI), which is defined as follows in Eq. (16). PI = [100× ([Na+] + [HCO3-]1/2) / [Na+] + [Ca2+] + [Mg2+]
(16)
These ions are expressed as meq/L. Moreover, PI is classified under class I (>75%), class II (25-75%), and class III (
