Sonochemical synthesis and characterization of emulsion polymer for

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Journal of Molecular Liquids 255 (2018) 556–561

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Journal of Molecular Liquids journal homepage: www.elsevier.com/locate/molliq

Sonochemical synthesis and characterization of emulsion polymer for sorption of lanthanides Emad Hassan Borai a, Mahmoud Goneam Hamed a,⁎, Ahmed Mohamed El-kamash a, Mohamed Mohamed Abo-Aly b a b

Hot Laboratories Center, Atomic Energy Authority, 13759, Egypt Chemistry Department, Faculty of Science, Ain-shams University, Cairo, Egypt

a r t i c l e

i n f o

Article history: Received 17 November 2017 Received in revised form 23 January 2018 Accepted 24 January 2018 Available online 31 January 2018 Keywords: Ultrasonic Nanoparticale Rare earth elements Polymers Nanocomposite

a b s t r a c t Recent advances in nanostructure materials have been developed by new synthetic method that provides control over size and chemical structure. The utilization of high intensity ultrasound has been investigated for synthesis of nanostructure polymer that is often unavailable by conventional methods. The preparation of emulsion polymer of carboxy methyl cellulose (CMC) as a backbone with grafting of methyl acrylate and acrylic acid has been investigated using ultrasonic irradiation at 15 min and Tween 80 as a surfactant which, hardly formed by conventional co-polymerization methods. Tween 80 was immersed inside the polymer matrix to improve interfacial tension between polymer and outer sphere water molecule, as well as to overcome the aggregation and compact of the component inside the polymer which, facilitate the grafting reaction. The influence of surfactant type, ultrasonic time and temperature on the particle morphology was studied. Moreover, Nitrilo tri-acetic acid (NTA) was grafted during the polymerization process to increase the effective function groups and hence increasing the sorption capacity toward Lanthanum (La3+), Cerium (Ce3+), Neodymium (Nd3+), Gadolinum (Gd3+) and Uranium (U4+) metal ions. The results showed relatively high sorption capacity reached to110, 121,169, 131, 158, 198 for La3+, Ce3+, Nd3+, Eu3+, Gd3+ and U4+ mg/g metal ions respectively. © 2018 Elsevier B.V. All rights reserved.

1. Introduction Recently, the ultrasonic polymerization(USP) technique becomes an essential for the synthesis of nano-size materials. The processing of nano materials requires higher efforts to break agglomerates and to overcome bonding forces. In general, ultrasound devices operates frequencies from the range of kilohertz to gigahertz. The desired sonochemical effects of the ultrasonication of liquids–including homogenization, dispersing, de-agglomeration, emulsification and extraction are caused by cavitations. The ultrasonic irradiation increase the attractive force at solution matrix which, produce high concentrations of H• and OH• radicals in water [1]. Posteriorly, the Cavitation bubbles can be formed. The resultant cavitations bubble absorb the gas from the matrix to expand until they collapse at the maximum volume. According to “hot spot” mechanism, the presence of cavitation bubbles act as a hot spot in the solvent. The presence of double bonds of monomer in or beside cavitation bubbles as it's known, rupture to radicals which, initiating the polymerization [2]. According to the primary physical phenomena associated with ultrasound polymer synthesis are controlled to provide cavitations-induced ⁎ Corresponding author. E-mail address: [email protected] (M.G. Hamed).

https://doi.org/10.1016/j.molliq.2018.01.151 0167-7322/© 2018 Elsevier B.V. All rights reserved.

polymer with a unique interaction between energy and the matrix. These extraordinary conditions permit access not only to assist the dispersion for nonmaterials, but also act as a special initiator to enhance the innovation of polymer composites [3]. The wide applications of sonochemistry in synthesis have attracted more attention, not only in academic search, but also in different fields of chemistry. For example from literature, during the preparation of polysilylene polymers by the reductive coupling of dichlorosilanes with sodium in toluene over 100 °C, the process is poorly reproducible with low molecular weight distributions. On the other hand, the synthesis of polysilylene at ambient temperature in the presence of ultrasound, produces monodisperse high molecular weight at the early stages of polymerization [4].These different results can be explained, when a liquid is exposed to ultrasonic waves, where gas nuclei or solid nuclei are presented. Cavities are formed that collapse very rapidly and the pressures and shear forces developed during collapse can be appreciable. The extreme conditions produced by ultrasound act as a special initiator to allow chemical bonds to break and enhance polymerization. Oil-in-water nano-emulsion of D-limonene was prepared aggressively by encapsulation technique. For this purpose, sonicator and an air-driven micro fluidizer are used to prepare the emulsions. The results demonstrated that the two methods were responsible for producing nano-emulsions of the size range of 150–700 nm, the sonication

E.H. Borai et al. / Journal of Molecular Liquids 255 (2018) 556–561

100

a

95

b

90 85 T

T

100 98 96 94 92 90 88 86 84 82 80 78 76 74 72 70 68 66 64 62 60 4000

557

80 75

R3 3500

3000

2500

2000

1500

1000

500

70 65

4000 3500 3000 2500 2000 1500 1000 500 Wave number( Cm -1)

-1

Wave number( Cm )

Fig. 1. FTIR of the polymeric materials (a) before and (b) after ultrasonic irradiation.

produced emulsions with narrower particle size distributions and more convenient in terms of operation [5]. From the literature, the size of the emulsions decreased with increasing of sonication time. However, sonication at optimum conditions was necessary for emulsification at which, the emulsion size would either increases or have a little change with further processing. The presence of fillers such as NTA is a greater factor and showed a significant effect on the properties of synthesized composites and controls the performance of the composites in the state of dispersion of fillers in the matrix [6]. Fillers can easily form bundles and the aggregation process decreases their aspect ratio thus reducing their efficiency as fillers. Magnetic stirring or shear mixing has also been used to disperse the fillers but they show poorer dispersions yield than sonication. In the present work, Nitrilo tri-acetic acid (NTA) was grafted during the ultrasonic polymerization process of CMC as a backbone to increase the effective function groups and hence increase the sorption capacity toward lanthanides and actinide metal ions. 2. Experimental In the present study all chemicals and reagents are used with analytical grade and the experiments were performed using de oxygenated double distilled water which, bubbled using pure nitrogen gas at temperature 80 °C.

only to reduce the heating up of suspensions during sonication but also, to get high efficiency of de-agglomeration [6]. The vessel of suspension was cooled using an ice-water bath. FTIR (Fourier transformed infrared) spectrum of polymer was recorded by VECTOR22 FT-IR spectrometer using KBr to form disk, performed on a computerized spectrophotometer in the range of 4000– 400 cm−1. Monomer conversions were determined gravimetrically. Thermal analysis was undertaken using a Shimadzu thermo gravimetric analyzer model TGA-50 (Tokyo, Japan). The thermal stability was investigated at a heating rate of 10 °C/min, under nitrogen atmosphere (20 ml/min) from room temperature up to 800 °C. Scanning electron microscope (SEM) were carried out by JEOL-JSM 6510 LA (Japan) and used for investigation the pore structure at high magnification of an electron beam. Metal ions concentrations were measured by computerized UV/Vis double beam spectrophotometer using 4–(pyridyl–2–azo) resorcinol monosodium salt (PAR) as sensitive coloring reagent. The percent uptake, capacity and the distribution coefficient were calculated respectively, by: %uptake ¼

ðCi−CeÞ 100 Ci

ð1Þ

qðmg=g Þ ¼

ðC i −C e ÞV m

ð2Þ

2.1. Instruments The dispersion of particles inside the polymer matrices was carried out with a Transducer Digital Sonifier_ Model 450 (Hielsher Ultrasonics Corporation, Germany). Its maximum power input and frequency are 400 W and 20 kHz, respectively. The ultrasonic horn that was immerged in suspension has a tip diameter of 13 mm and the sonication amplitude (tip movement) is in the range of 10–65 lm. Pulse mode was used not

Kd ¼

ðC i −C e Þ  V  1000 m

ð3Þ

where (q) is the maximum capacity (mg/g), Ci and Ce are the initial and equilibrium concentrations (mg/L) of metal ion respectively, m is the mass of the adsorbent used (g), V is the initial volume of the aqueous solution (L).

Fig. 2. SEM photographs of (a) particles obtained under ultrasound irradiation, at 20 °C, (b) particles obtained without ultrasound irradiation.

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E.H. Borai et al. / Journal of Molecular Liquids 255 (2018) 556–561

2.2. Preparation of polymer The emulsion polymer was synthesized using two different methods including ultrasonic irradiation and the traditional mechanical stirring in a water bath. In both cases, the carboxy methyl cellulose was dissolved in double distilled water with N,N′-methylene diacrylamide (DAM) mixed with Nitrilio triacetic acid (NTA) which, dissolved in sodium hydroxide. Amorphous ferrous sulphate was dissolved in distilled water then mixed with methyl acrylate and acrylic acid. The mixture exposed to ultrasonic irradiation in controlled temperature approximately 5 °C to get rid of the negative effect (flocculation or coagulation) for 15 min. Finally, the polymerization occurred by adding ammonium persulphate as initiator in water bath for 3 h at 70 °C. The formation of emulsion polymer confirmed the hypothesis that cavitations of the sonication process cause rapture of macromolecules and creation of free radicals which, are attached as lateral branches making polymer more grafted.

3. Results and discussion 3.1. Characterization of the prepared adsorbents 3.1.1. FTIR analysis The prepared polymer characterized by FTIR spectroscopy as shown in Fig. 1, indicates that hydrogen bonding is formed between (CMC) network and the linear monomers. The broad band at 3431 cm-1 belong to stretching of a C\\H overlapped with OH of carboxylic acid [7]. The absorption band at 1634 and 1736 cm-1 indicate the presence of stretching band of C_O belong to carboxylic acid and C_C alkene respectively. The absorption band at 2924 and 1376 cm-1 indicate the presence stretching and bending of sp3 C\\H bonds. The absorption band at 1160 and 1111 cm-1 indicate the presence of acyl (C\\O) aromatic and alkoxy C\\O which belong to carboxylic acid and CMC respectively [8]. The absorption band at 1033 cm-1 indicates the presence of N\\C which, belongs to NTA. This means that NTA is successfully impeded during the polymerization process. The absorption peak appears at 2847 cm-1 indicating OH stretch of the carboxylic acid. The presence of these bands verifies the polymerization process of all components using ultrasonic technique [9–10].

3.1.2. Scanning electron microscope (SEM) The SEM results of the emulsion polymer prepared by ultrasonic (a) and without ultrasonic (b) are shown in Fig. 2(a and b). The morphology illustrates the cavitations and uniform pores of the polymer prepared by ultrasonication. The use of sonication resulted in smaller particles than that in the absence of the sonication. As the sonication period increases, the formation of de-agglomerated particles appears. So the success of this method will likely depend on the nature of the molecule used. Fig. 2b shows nonporous surface for the polymer prepared by conventional stirring method and produced massive form [11]. DTA uV 40.00

TGA mg 15.00 -20.380 %

10.00

TGA

20.00

-15.107 %

DTA

-23.009 %

5.00

200.00

600.00 400.00 Temp [C]

-9.568 % -6.836 %

800.00

Fig. 3. DTA and TGA curves for polymer.

1000.00

O

O

+ H2O

O HO

O Scheme 1. Effect of heat on acrylic acid (AA) (dehydration).

3.1.3. Thermogravimetric analysis (TGA) Thermo gravimetric analysis (TGA) and differential thermal analysis (DTA) were used to provide an alternative kinetic model of the prepared polymer degradation as shown on Fig. 3. The prepared polymer was heated at the rate of 10 °C/min. The degradation precedes in forth stages. The first stage from (27 to 201 °C) with a maximum endothermic peak at 195 °C exhibits a weight loss of 6.5% and 0.22 mg which, is due to removal of all surface and matrix-bound moisture present in the polymer and removal of absorbed or coordinated water molecules [12]. The second stage from (201 to 324 °C) which, shows endothermic peaks at 299 °C exhibits a weight loss of 24.3% and 0.82 mg due to CO2 release as result of dehydration of acrylic acid (Scheme 1). The third stage from (324 to 522 °C), with a maximum endothermic peak at 450 °C shows a high weight loss reached to 48.0% and 1.6 g. This may be due to short chain fragments created by chain scission and removal of volatile hydrocarbon that formed in the oxide form [13]. The fourth stage from (524 to 800 °C) is characterized by a weight loss of 21.2% and 0.46 mg can be attributed to the process accompanying the main chain scission and complete degradation to the oxide form [14]. 3.2. Physicochemical properties 3.2.1. Swelling behavior The swelling behavior of resin was tested in different solvents with known resin mass (Wi). The polymeric resin was separately immersed in excess distilled water or solvents and left for one day to attain swelling equilibrium. Swollen samples were weighed (Wf) as shown in Table 1. The swelling degree (PS) was calculated as shown in Eq. (4) [15]. Ps ¼

ðWf −WiÞ 100 Wi

ð4Þ

The swelling percent of emulsion polymer (with or without using NTA) was tested using ultrasonic probe or water bath. The maximum swelling was observed in water reached to 68%. This may be due to possible hydrophilic properties of the porous particles originated due to grafting of monomers onto CMC. The swelling behavior obeyed to the following order: water N NaOH N CCl4. The results show that % swelling of the polymer prepared without NTA in water bath is higher than that prepared with NTA. This can be attributed not only to the increase in the extent of cross linking between the polymeric chains as a result of addition NTA but also due to the relatively low solubility of NTA in aqueous solution [16]. The obtained low swelling percent of the prepared material helps to increase the chances of getting high sorption capacity of the metal ions rather than hydrogen ions of the water molecules, this can be attributed to the higher association probability between the filler and the polymer matrix which, increases the degree of crosslinking for a

0.00 -20.00

-7.588 %

-0.00 -0.00

O

OH

-40.00

Table 1 Swelling behavior of the prepared emulsion polymer in different solvents. Solvent

Filler of resin

Initial weight (mg)

Final weight (mg)

% swelling

Water NaOH CCL4 Water

NTA NTA NTA Without NTA

50 50 50 50

84 ± 0.6 75 ± 0.5 70 ± 0.8 96 ± 0.5

68 ± 0.7 50 ± 0.4 40 ± 0.6 92 ± 0.8

E.H. Borai et al. / Journal of Molecular Liquids 255 (2018) 556–561

559

Table 2 Chemical stability of the prepared resin in acidic and alkaline media. Wf (mg) in 1 N

%weight loss

Wf (mg) in 6 N

%weight loss

Wf (mg) in 10 N

%weight loss

50 50 50 50

50 50 50 50

0% 0% 0% 0%

50 50 50 45

0% 0% 0% 10%

50 ± 0 47 ± 0.4 45 ± 0.3 20 ± 0.8

0% ± 0 6% ± 0.5 10% ± 0.4 60% ± 0.9

limit at which, the polymer becomes completely satisfied by the aqueous solution. 3.2.2. Evaluation of chemical stability Chemical stability of polymer is the ability of polymer material to retain their initial chemical structure [17]. In this respects, the chemical stability of the prepared polymer was tested in acidic and alkaline media. The weight loss of the polymer was calculated as shown in Eq. (5). %Weight; loss ¼



ðWi−Wf Þ 100 Wi

ð5Þ

where Wi is the initial weight of the sample and Wf is the final weight of the sample. The emulsion polymer showed that, the polymer has chemical stability in alkaline media rather than in acidic media as shown in Table 2. The chemical stability of the prepared polymer in the acidic media follow the order: HCl N HNO3 N H2SO4. This was due to deactivation of active sites on grafted polymer backbone in different acids. The % weight loss is relatively low till 10 M of HCl and HNO3. Significant degradation (60%) of the prepared polymer was observed in 10 M of H2SO4. 3.2.3. Evaluation of radiation resistance The radiation stability (radiation resistance) of polymer material reflects their physio chemical stability on the one hand and their serviceability under ionizing radiation on the second hand (in the operation of atomic reactor and radioactive waste treatment) [18]. The results (omitted for brevity) demonstrated that the emulsion polymer show radiation stability at 40 K·Gry without weight loss and the loss of weight reached to 0.5 wt% at 60 K·Gry. The obtaining results show radiation resistance of emulsion polymer which, depends on the extent of molecular changes due to the sonication polymerization process. This process creates conjugated double bonds which, exhibit a lower sensitivity to ionizing radiation than polymer with saturated bonds [19]. 3.3. Optimization of the preparation process of the emulsion polymer The emphasis in scientific research on emulsion polymer was mainly focused on influence of monomer type and monomer composition, crosslinking and polymerization process on the emulsion. In this respects, preliminary experimental trials have been tested using different backbone such as schitosan, cellulose and Carrageenan instead of CMC. These materials showed lower polymerization degree than CMC (the results omitted for brevity). Therefore, CMC is selected as a backbone in the present study. Several other parameters which play an important

role in the preparation of sonicated emulsion polymer, expressed in sonication time and surfactant type have been investigated and evaluated by their effect of sorption of U4+ metal ions. 3.3.1. Effect of sonication time on percent uptake of U4+ The percent uptake of U4+ is calculated at different ultrasonic time (10, 15, 20, 25and 30 min) in ice water bath to control temperature. Another trial was performed using traditional mechanical stirring without using ultrasonic technique. The results (omitted for brevity) demonstrated that ultrasonic homogenizer have a greater effect in dispersing of NTA and de-agglomeration of polymer matrices. Therefore, the percent uptake increased with the increasing of sonication time starting from 63% without using sonication and reached to 79, 93, 93, 93, 94% at 10, 15, 20, 25and 30 min's respectively. The increasing of the sonication time N30 min leads to negative result. 3.3.2. Effect of surfactant type on percent uptake of U4+ From molecular geometrical consideration, surfactant with bulky hydrophobic structure is more efficient in forming the emulsion due to high solubilization of organic molecules, which, is good for lower interfacial tension in formation of emulsions [20–21]. The accelerating efficiency of a backbone polymer (CMC) depends on its solubility and reactivity in overall matrix. Generally speaking, the solubility of CMC in a polymer depends on its polarity and type of surfactant. The polarity of the CMC can be expressed by its hydrophilic–lipophilic balance (HLB) value calculated by Davies equation [22]. In this study, comparative study for different types of surfactant on the emulsion polymer properties has been investigated. Four types of surfactants with different HLB values expressed in ethylenediamine tetrakis(propoxylate-block-ethoxylate) tetrol (Tetronic 701) as anionic surfactant (HLB 5.0), span80 Sorbitan monooleate (HLB 4.3), TritonX100 (HLB 13.5) and Tween80 polyethylene glycol(20)Sorbitan monooleate (HLB 15.0) as nonionic surfactants have been tested during the emulsion polymerization process. Hydrophilicity increases with increasing HLB value. At high solubility of CMC, the radiation cross-linking efficiency of CMC is proportional to the specific un-saturation (SU, moles of double bonds per 100 g of the monomer) [23]. Depending on this evidence, the results demonstrated (Table 3) that, the percent uptake for U4+ metal ion was found to be 100

U Gd Nd Eu Ce La

90 80 70

Uptake %

NaOH HCl HNO3 H2SO4

Initial weight (mg)

60 50 40

Table 3 Effect of surfactant type of different HLB values on percent uptake of U4+.

30 20

Surfactant

Type

HLB

% uptake

Span 80 Tetronic 701 Tritonx100 Tween80

Nonionic Anionic Nonionic Nonionic

4.3 5.0 13.5 15.0

Not formed 52 ± 0.3 71 ± 0.9 94 ± 0.5

10 0

20

40

60

80

100

120

140

160

180

200

Time (Sec)

Fig. 4. Effect of time on the percent uptake of resin (0.05 g resin, 10 ml, pH = 4.0 at 37 °C).

560

E.H. Borai et al. / Journal of Molecular Liquids 255 (2018) 556–561 40

U Gd Nd Eu Ce La

35

Capacity mg/gm

30 25 20 15 10 5 0 1

2

3

4

5

Fig. 5. Effect of pH on the sorption of resin (0.05 g resin, 10 ml and time = 2 h's at 37 °C).

52, 71 and 94% for Tetronic 701,Tritonx100 and Tween80 surfactants respectively. On the other hand, span80 don't permit the formation of emulsion polymer. According to the obtained results, the percent uptake increased with the increasing of HLB value of surfactant and the prepared polymer obeys the oil in water phase emulsion technique. Therefore, Tween80 have a greater conversion percent more than Tritonx100 and SDBS surfactants.

3.4. Applicability of polymeric resin for sorption of some lanthanide and uranium metal ions 3.4.1. Effect of contact time on metal sorption The percent uptake of the prepared polymer toward La3+, Ce3+, Nd3 + , Eu3+, Gd3+, and U4+ metal ions have been investigated by a batch equilibration technique as a function of time. As shown in (Fig. 4), the percent uptake of resin increased with the increasing of continued time until equilibrium. The maximum percent uptake attained at 2 h for all the investigated metal ions. The maximum sorption equilibrium follow the order U4+ N Gd3+ N Nd3 N Eu3+ N Ce3+ N La3+ metal ions. The high percent uptake (98%) for U4+ may be attributed to the superabundant function groups (NTA) of the resin at the initial stage of the sorption process in addition to the active sites present on the surface. On the other hand, the maximum percent uptake of the un-impregnated resin (without introducing of NTA) at the same condition for uranium metal ions decreases to 74% which, illustrates the benefits of NTA presence in the components and reflects a convenient capacity.

3.4.2. Effect of pH on sorption behavior The pH of the solution is the significant factor for controlling the sorption process [26]. Fig. 5 illustrates a typical dependence of metal ion uptake on the solution pH. It was found that as the pH value increased from 1.0 to 5.0, the sorption capacity of resin increased and reached to 39.2, 39.2, 28, 24, 24, 20 mg/g at pH 5.0 for the studied metal ions U4+,Gd3+, Nd3+, Eu3+, Ce3+ and La3+ respectively. This can be explained by the presence of a-large number of carboxyl (\\COOH) groups in the structure of the resin from NTA and acrylic acid groups, which, can dissociate to form carboxylate ion (COO\\) at higher pH. However, at pH values higher than 5.0, the metal hydrolysis will be takes place [27–30]. On the other hand, at low pH values, the competitive sorption of H+ and metal ions on the same active sorption site causes a decrease in metal uptake. Significant change in selectivity of polymer contain NTA toward U4+ and Gd3+ metal ions rather than light rare earth elements was observed as a function of increasing pH Hence, significant selectivity of the prepared NTA-polymer toward U4 + and Gd3+ was obtained at pH 5.0. 3.4.3. Effect of initial metal ion concentration on sorption behavior Solid state speciation of U4+ and lighter lanthanide such as La3+ metal ions with the prepared sorbent has an analytical importance to understand the sorption mechanism and the structure of the practically adsorbed species. The species of U4+ and La3+ metal ions on emulsion polymer surfaces are not only dominated by the properties of adsorbent, but also affected by the structure of ionized species at various pH values. As shown in Fig. 6a, the aqueous uranium speciation diagram, it was found that the uranyl ion (UO2+ 2 ) is the dominated species at pH b 4. Knowing that the free uranyl ion in acidic solution has five water molecules in its first hydration shell ([UO2(H2O)5]2+) [31]. Under this condition, uranium typically occurs in the heptavalent or form as the mobile aqueous uranyl ion (UO2+ 2 ) [32]. On the other hand, La3+ hydrolysis started at pH 6.0 as given in Fig. 6b. In this respect, the effect of metal ion concentration on the sorption capacity of the prepared resin for UO2 2+ and La3+ ions onto polymer surface has been studied at pH 4.0 to avoid the metal hydrolysis, in the range from 100 to 500 mg/L as presented in Fig. 7. The obtained results demonstrated that the maximum sorption capacity reached to 110, 121,169, 131, 158 and 198 mg/g for La3+, Ce3+, Nd3+, Eu3+, Gd3+ and U4+ metal ions respectively. These sorption capacities are relatively high as compared with the other chemical sorbents [33–34]. The obtained results demonstrated that the maximum sorption capacity reached to 110 and 198 mg/g for La3+ and U4+ metal ions respectively. These sorption capacities are relatively high as compared with the other chemical sorbents [33–34].

a 0

b

La3+

H+

La(OH)3(c)

0 H+ LaOH2+ 2+

UO2 (OH)2 .H2 O(c)

UO2OH+ (UO2 )2 (OH) 2 2+ (UO2 )3 (OH)5 + (UO2 ) 2 OH3+ (UO2 )3 (OH)4 2+

-4

-6

Log Conc.

UO2 Log Conc.

OH−

-2

-2

(UO2 )4 (OH)7 +

OH− UO2(OH)2(aq)

-8

UO2 (OH)3 − 0

1

2

3

4

5

6

7

-4

La(OH) 2 +

-6 La(OH) 3 -8

La(OH) 4 − 2

4

pH

Fig. 6. Speciation of (a) uranium (VI) and (b) lanthanum (III) metal ions.

6

8 pH

10

12

E.H. Borai et al. / Journal of Molecular Liquids 255 (2018) 556–561 220 200 180

Capacity mg/gm

160 140

la Ce Nd Eu U Gd

120 100 80 60 40 20 0 0

100

200

300

400

500

600

mg / l

Fig. 7. Effect of initial metal ion concentration on the sorption of resin (0.05 g resin, 10 ml and time = 2 h at 30 °C and pH = 4).

4. Conclusion Emulsion polymer particles have been successfully synthesized as a template material using USP technique. The prepared sonicated emulsion polymer have been functionalized by NTA filler. It was verified that during polymerization process the intermolecular hydrogen bond between carboxy methyl cellulose (CMC) and both methyl acrylate and acrylic acid had taken place instead of random copolymerization. The influence of the type and amount of the surfactant and the ultrasonic time and temperature on the particle morphology was studied. Optimization study for ultrasonic preparation showed that ultrasonic frequency of 40 kHz, temperature of 20 °C at 15 min. The interfacial tension between the prepared NTA-polymer and water molecules was efficiently reduced due to the grafting reaction of the added surfactant which, improved the conversion yield, effective capacity and helpful to form the obtained structure. The sorption process was carried out at pH 4.0 according to the solid state speciation for all the studied metal ions to avoid metal hydrolysis. The maximum sorption capacity for La3+, Ce3+, Nd3+, Eu3+, Gd3+ and U4+ metal ions reached to 110, 121,169, 131, 158 and 198 mg/g respectively. These sorption capacities indicates the superior characteristics of the prepared emulsion NTApolymer. References [1] D. Avik, D. Sen, S. Mazumder, A.K. Ghosh, C.B. Basakc, K. Dasgupta, Formation of nano-structured core–shell microgranules by evaporation induced assembly, RSC Adv. 5 (2015) 85052–85060. [2] W.T. Richards, A.L. Loomis, The chemical effects of high frequency sound waves I. A preliminary survey, J. Am. Chem. Soc. 49 (1927) 3086–3100. [3] D. Sen Avik Das, S. Mazumder, A.K. Ghosh, C.B. Basak, K. Dasgupta, Formation of nano-structured core–shell microgranules by evaporation induced assembly, RSC Adv. 5 (2015) 85052–85060. [4] S. Fatemeh Shahangi, A. Kamran, Sonochemical procedures; the main synthetic method for synthesis of coinage metal ion supramolecular polymer nano structures, Ultrason. Sonochem. 31 (2016) 51–61. [5] Zhang Ke, P. Bong-Jun, F. Fei-Fei, J.C. Hyoung, Sonochemical preparation of polymer nanocomposites, Molecules 14 (2009) 2095–2110. [6] J. Seid Mahdi, Yinghe He, B. Bhesh, Preparation of D-limonene oil-in-water nanoemulsion from an optimum formulation, Int. J. Food Prop. 9 (2006) 3. [7] C.D. Anderson, E.D. Sudol, M.S. El-Aasser, Elucidation of the miniemulsion stabilization mechanism and polymerization kinetics, J. Appl. Polym. Sci 90 (2003) 3987–3993.

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