聚丙烯酸/氧化石墨烯复合水凝胶制备及对亚甲基蓝吸附

以丙烯酸(AA)为原料,二丙烯酸酯(Pul DA)分散的氧化石墨烯(GO)纳米胶粒(GO-Pul DA)为增强剂,N,N'-亚甲基双丙烯酰胺(BIS)为交联剂,通过自由基共聚合制备了一系列结构均一的聚丙烯酸/氧化石墨烯复合水凝胶(PAA/GO-Pul DA)。考察了BIS质量浓度、GO质量浓度以及溶液pH值对复合水凝胶力学性能、吸水性和亚甲基蓝(MB)吸附量的影响。结果表明,当GO质量浓度从0.1 g/L增加至1.0 g/L时,复合水凝胶拉伸强度从5.0 k Pa增加至10.4 k Pa,断裂伸长率高于100%,当GO的质量浓度为0.3 g/L时,复合水凝胶的断裂伸长率最高为151%;复合水凝胶表现出pH敏感的高吸湿性,pH从3.0增加至6.8时,平衡溶胀比(SRe)变化可达386 g/g,pH=6.8时最大SRe高达490 g/g。当溶液pH值从3.0增加至11.0时,PAA/GO-Pul D对MB的平衡吸附量(qe)可增加1 400~1 500 mg/g,pH=11.0时最大的qe高达1 789 mg/g。复合水凝胶对MB的吸附行为符合准一级动力学模型。5次吸附-解吸附循环后,相对于首次吸附,PAA/GO-Pul D对MB的吸附能力仍保持高达60%,解吸附效率高于90%。     

Hydroxyethyl cellulose hydrogel modified with tannic acid as methylene blue adsorbent

This work developed an effective way to improve the methylene blue (MB) adsorption performance of cellulose-based hydrogel by modified with tannic acid (TA). HEC-co-p(AA-AM)/TA hydrogel was synthesized by grafting of acrylic acid (AA) and acrylamide (AM) onto hydroxyethyl cellulose (HEC), followed by modified with TA. Fourier transform infrared spectroscopy manifested that AA and AM were successfully grafted onto the hydrogel, and TA was immobilized in the hydrogel. Field emission scanning electron microscope demonstrated that the hydrogel after TA modification had a homogeneous pore structure. Brunauer-Emmett-Teller (BET) surface areas, total pore volume, and average pore diameters of the hydrogel are 11.821 m² g⁻¹, 0.0641 cm³ g⁻¹, and 2.538 nm, respectively. The high swelling ratio (1179.2 g g⁻¹ in deionized water) was in favor of the MB adsorption. The results of the adsorption experiments illustrated that HEC-co-p(AA/AM) hydrogel had excellent MB adsorption performance. As the pH increases, the electrostatic attraction is enhanced, and the adsorption capacity is improved. The adsorption process was more fit with pseudo-second-order kinetics, and the maximum adsorption capacity (3438.27 mg g⁻¹) was determined by Langmuir model. Thermodynamic studies suggested that the adsorption process is spontaneous, exothermic, and entropy reduction. X-ray photoelectron spectroscopy analysis confirmed that MB molecules were reacted with the oxygen atoms in hydroxyl and carboxyl groups by ion-exchange. High reusability demonstrated that the hydrogel could be a potential candidate for removal cationic dye from industrial effluents.     

Behaviors of polyelectrolyte AAm/AMPS/bentonite composite hydrogels in uptake of uranyl ions from aqueous solutions

Uranyl ion (UO₂²⁺) sorption properties of polyelectrolyte composite hydrogels made by the polymerization of acrylamide (AAm) with 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) and clay such as bentonite (Bent) were investigated as a function of composition to find materials with swelling and uranyl ion sorption properties. Highly swollen AAm/AMPS hydrogels and AAm/AMPS/Bent composite hydrogels were prepared by free radical solution polymerization in aqueous solutions of AAm with AMPS as co‐monomer and two multifunctional crosslinkers such as ethylene glycol dimethacrylate (EGDMA) and 1,4 butanediol dimethacrylate (BDMA). Swelling experiments were performed in water at 25°C, gravimetrically. The influence of AMPS content in hydrogels was examined. Uranyl ion adsorption from aqueous solutions was studied by batch sorption technique at 25°C. The effect of uranyl ion concentration and mass of AMPS on the uranyl ion adsorption were examined. Finally, adsorption capacity (the amount of sorbed uranyl ion per gram of dry hydrogel) (q) was calculated to be 0.67 × 10⁻³–2.11 × 10⁻³ mol uranyl ion per gram for the hydrogels. Removal effiency of uranyl ions (RE%) was changed range 9.05–29.92%. The values of partition ratio (K_d) of uranyl ions was calculated to be 0.10–0.43 for AAm/AMPS hydrogels and AAm/AMPS/Bent composite hydrogels, respectively. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Synthesis and characteristics of an amphoteric semi‐IPN hydrogel composed of acrylic acid and poly(diallydimethylammonium chloride)

Semi‐interpenetrating polymer network (IPN) hydrogels, with acrylic acid (AA) and poly(diallydimethylammonium chloride) (PDMDAAC), were constructed by a sequential IPN method. The characterizations of the IPN hydrogels were investigated by FTIR, DTA, and swelling tests under various conditions. The prepared semi‐IPN hydrogels exhibited relatively high swelling capacity, in the range of 477–630 g/g at 25°C. The results show that the swelling capacity of AA/PDMDAAC semi‐IPN hydrogels was pH and temperature dependent. Swelling behaviors were also studied in the different salt solutions. Swelling kinetic parameters are given. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 345–350, 2007     

Synthesis and characterization of novel poly(acrylamide‐co‐acrylic acid‐co‐2‐hydroxy ethyl actylate) hydrogels: Mathematical approach in investigation of swelling kinetics and diffusion models

In this study, a series of poly(acrylamide‐co‐acrylic acid‐co‐2‐hydroxy ethyl actylate) [AM‐co‐AA‐co‐HEA] hydrogels have been synthesized by varying the acrylic acid (AA)content over eightfold in feed in the range of 33.34–93.76% by keeping other monomer constant. These hydrogels were characterized by FTIR, SEM analysis, elemental analysis, residual acrylic acid analysis, network parameters, and dynamic swelling behavior. The swelling study showed that equilibrium swelling ratio was nonlinearly increased with increasing AA content. Interestingly, the equilibrium swelling ratio decreased from 53.42 to 48.52 for 75–80% AA content hydrogel. The swelling data were found to satisfactorily fit Fick's second law, demonstrating that diffusion rate of water uptake was primarily Fickian. From model fitting, it was observed that early model was applicable for first 30% water absorption, and late model was applicable for latter 70% water absorption for increasing AA content from 33.34–90.90%. For 93.76% AA, early‐time model was extended up to first 50% of water absorption and late model was contracted for latter 50% water absorption, indicating that excessive AA content affects the applicability range of early‐time and late‐time diffusion models for water absorption. Etters model was best applicable to all type of hydrogels and followed over all swelling range. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Adsorption and heat‐energy‐aid desorption of cationic dye on a new thermo‐sensitive adsorbent: Methyl cellulose/calcium alginate beads

The adsorption and heat‐energy‐aid desorption of methylene blue (MB) on a thermo‐sensitive adsorbent of methyl cellulose/calcium alginate beads (MC/CABs) has been studied. The addition of methyl cellulose intensified the desorption ability of adsorbent, and boosted the difference of adsorption capacity of adsorbent between low temperature and high temperature. At the mass ratio of methyl cellulose to sodium alginate of 2:1, the difference of adsorption capacity of MC/CABs between 20 and 60°C reached 20.48 mg g^?1. The effects of temperature, time and initial MB concentration on adsorption performance were investigated in detail. The MB adsorption on MC/CABs followed the pseudo‐second‐order kinetic model. The equilibrium data was fitted well with Langmuir isotherm. The maximum adsorption capacity of 336.70 mg g^?1 exhibited MC/CABs had a good adsorption capability. Thermodynamic analyses showed high temperature was not favorable to MB adsorption, and MC/CABs had a distinct superiority in desorption of adsorbate with heat‐energy‐aid. Lastly, the possible mechanisms involving in adsorption and heat‐energy‐aid desorption were presented. POLYM. ENG. SCI., 56:1382–1389, 2016. © 2016 Society of Plastics Engineers     

Graft copolymerization of acrylic acid onto cellulose: Effects of pretreatments and crosslinking agent

The graft copolymerization of acrylic acid (AA) and 2‐acrylamido 2‐methylpropane sulfonic acid (AASO₃H) onto cellulose, in the presence or absence of crosslinking agent N,N′‐methylene bisacrylamide (NMBA), by using different concentrations of ceric ammonium nitrate (CAN) initiator in aqueous nitric acid solution at either 5 or 30°C was investigated. To investigate the effect of pretreatment of cellulose on the copolymerization, before some grafting reactions cellulose was pretreated with either 2 or 20 wt % NaOH solutions or heated in distilled water/aqueous nitric acid (2.5 × 10^?3 M) at 55°C. To determine how the excess of initiator affects the grafting and homopolymerization, separate reactions were carried out by removing the excess of ceric ions by filtration of the mixture of initiator solution and cellulose before the monomer addition. Extraction‐purified products were characterized by grafting percentage and equilibrium swelling capacity. Pretreatment of cellulose with NaOH solutions decreased the grafting percentage of copolymers. In the case of AA–AASO₃H mixtures, nonpretreated cellulose gave a higher grafting percentage than NaOH‐pretreated cellulose. Filtration also lowered the grafting of AA on the cellulose in the cases of pretreatment with either water or nitric acid. Copolymers with the highest grafting percentage (64.8%) and equilibrium swelling value (105 g H₂O/g copolymer) were obtained in grafting reactions carried out in the presence of NMBA at 5°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2267–2272, 2001     

Functionalization of polyvinyl alcohol hydrogels with graphene oxide for potential dye removal

Because of highly frozen macromolecule chains, polyvinyl alcohol (PVA) hydrogels have never been used for dye removal. This work focuses on improving the adsorption capacity of the PVA hydrogel by using amphiphilic graphene oxide to improve its macromolecular chain mobility in crystal domain and introduce new functional groups. To evaluate its effectiveness, crystal structure, swelling kinetics, and model dye methylene blue (MB) adsorption of the as‐prepared PVA hybrid hydrogels were systematically investigated. The results indicate that the hybrid PVA hydrogels have lower crystallinity and less crystal stability, demonstrating the improved macromolecular chain mobility. Moreover, improved swelling ratios of PVA/GO hydrogels also illustrate the enhanced macromolecular chain mobility. MB adsorption experiment indicates that GO introduced can result in great improvement in MB adsorption. And the adsorption process follows the second‐order kinetic model and Morris–Weber model, which is determined by the intraparticle diffusion. Furthermore, MB adsorption isotherm follows Freundlich model and the adsorption is heterogeneous. Desorption studies indicate that the interaction between PVA hydrogels and MB consists of both physisorption and chemisorption. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39872.     

Swelling properties of CMC‐g‐poly (AAm‐co‐AMPS) superabsorbent hydrogel

A series of biopolymer‐based superabsorbent hydrogels based on carboxymethyl cellulose has been prepared by free‐radical graft copolymerization of acrylamide and 2‐acrylamido‐2‐methylpropan sulfonic acid (AMPS) in aqueous solution using methylenebisacrylamide as a crosslinking agent and ammonium persulfate as an initiator. The effect of variables on the swelling capacity such as: acrylamide/AMPS weight ratio, reaction temperature, and concentration of the initiator and crosslinker were systematically optimized. The results indicated that with increasing the amount of AMPS, the swelling capacity is increased. FT‐IR spectroscopy and scanning electron microscope analysis were used to confirm the hydrogel structure. Swelling measurements of the synthesized hydrogels in different salt solutions indicated considerable swelling capacity. The absorbency under load of the superabsorbent hydrogels was determined by using an absorbency under load tester at various applied pressures. A preliminary swelling and deswelling behaviors of the hydrogels were also studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Competitive removal of heavy metal ions by cellulose graft copolymers

The effect of composition of graft chains of four types cellulose graft copolymers on the competitive removal of Pb²⁺, Cu²⁺, and Cd²⁺ ions from aqueous solution was investigated. The copolymers used were (1) cellulose‐g‐polyacrylic acid (cellulose‐g‐pAA) with grafting percentages of 7, 18, and 30%; (2) cellulose‐g‐p(AA–NMBA) prepared by grafting of AA onto cellulose in the presence of crosslinking agent of N,N′‐methylene bisacrylamide (NMBA); (3) cellulose‐g‐p(AA–AASO₃H) prepared by grafting of a monomer mixture of acrylic acid (AA) and 2‐acrylamido‐2‐methyl propane sulphonic acid (AASO₃H) containing 10% (in mole) AASO₃H; and (4) cellulose‐g‐pAASO₃H obtained by grafting of AASO₃H onto cellulose. The concentrations of ions which were kept constant at 4 mmol/L in an aqueous solution of pH 4.5 were equal. Metal ion removal capacities and removal percentages of the copolymers was determined. Metal ion removal capacity of cellulose‐g‐pAA did not change with the increase in grafting percentages of the copolymer and determined to be 0.27 mmol metal ion/g_copolymer. Although the metal removal rate of cellulose‐g‐p(AA–NMBA) copolymer was lower than that of cellulose‐g‐pAA, removal capacities of both copolymers were the same which was equal to 0.24 mmol metal ion/g_copolymer. Cellulose did not remove any ion under the same conditions. In addition, cellulose‐g‐pAASO₃H removed practically no ion from the aqueous solution (0.02 mmol metal ion/g_copolymer). The presence of AASO₃H in the graft chains of cellulose‐g‐p(AA–AASO₃H) created a synergistic effect with respect to metal removal and led to a slight increase in metal ion adsorption capability in comparison to that of cellulose‐g‐pAA. All types of cellulose copolymers were found to be selective for the removal of Pb²⁺ over Cu²⁺ and Cd²⁺. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2034–2039, 2003     

Preparation of Sodium carboxymethylcellulose/poly(methyl acrylate) IPN hydrogels and their application for adsorption

Sodium carboxymethylcellulose/poly(methyl acrylate) (NaCMC/PMA) interpenetrating polymer networks (IPNs) were prepared by fractional step in 40 wt % ethanol solution with N,N′‐methylenebisacrylamide as a crosslinker. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimeter were used to characterize the NaCMC/PMA IPN hydrogels and confirm the IPN structure as well. Simultaneously, adsorption of the obtained IPN hydrogels to methylene blue (MB) was also investigated. It was observed that the adsorption of MB onto the hydrogels was mainly dependent on the initial concentration of MB and the pH of the solution. Adsorption rate of MB was much higher in the first 9 h than that in the following period and saturated adsorption amount of MB was 2370 mg/g at the initial MB concentration of 100 mg/L. Moreover, the adsorption capacity of the IPN hydrogels at the neutral pH condition is much higher than those at acid or alkaline pH conditions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41101.     

Removal of methylene blue from aqueous solutions by poly(2-acrylamido-2-methylpropane sulfonic acid-co-itaconic acid) hydrogels

In this study, removal of methylene blue (MB) from aqueous solution by poly(AMPS-co-IA) hydrogels was examined by batch equilibration technique. The effects of monomer ratio, concentration of initiator and crosslinker, pH, adsorption time, initial dye concentration and adsorption temperature on the removal of MB were studied. The results show that the removal of MB was highly effected by preparation conditions of hydrogel. The maximum removal was observed at 10/90 IA/AMPS monomer ratio, 1.0% KPS, and 10.0% MBAAm concentrations. Removal of MB was strongly affected by pH. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were applied. It was concluded that adsorption of MB on hydrogel followed pseudo-second-order kinetics. It was found that the adsorption isotherm of the MB fit Langmuir-type isotherms. From the Langmuir equation, the adsorption capacity was found as 1,000 mg/g for MB dye. Thermodynamic parameters suggest that the adsorption is a typical physical process, spontaneous, and exothermic in nature. Ten adsorption—desorption cycles demonstrated that the hydrogels were suitable for repeated use without considerable change in adsorption capacity. The results revealed that this hydrogels have potential to be used as an adsorbent for the removal of MB from aqueous solution.     

Comparative study of PEO and PVA hydrogels for removal of methylene blue dye from wastewater

In this study, poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO) hydrogels were synthesized and evaluated as adsorbent for dye removal from wastewater using methylene blue (MB) in aqueous solution as probe. PEO samples were photochemically prepared by varying irradiation time (1–16 h), while PVA samples were synthetized with different concentration of glutaraldehyde (GA) (0.03–0.48%). The obtained hydrogels were obtained through the analysis of a swelling test, scanning electron microscopy, and adsorption studies. PEO hydrogels adsorption capacity was dependent on the irradiation time, while the PVA hydrogel adsorption capacity reduces with GA concentration. Both hydrogels demonstrated a Langmuir isotherm adsorption model at the equilibrium and pseudo‐second order kinetic fits properly. pH studies showed that when pH reaches 12, the adsorbed MB amount is close to 8 and 2 times higher than pH = 2 both hydrogels. Photochemical preparation of hydrogels shows an easier way of tuning their properties in order to maximize dye removal. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45043.     

Synthesis and Properties of Temperature-Sensitive Hydrogel Based on Hydroxyethyl Cellulose

Hydrogels were prepared from modified hydroxyethyl cellulose by copolymerization with N-isopropylacrylamide. The equilibrium swelling ratio of hydrogel was measured in buffer solution with pH 7.0 from 25.0 to 45.0°C and the data obtained showed that hydrogels exhibited temperature sensitivity. The results of DSC analysis revealed that the low critical solution temperature (LCST) of hydrogels was enhanced by the introduction of hydroxyethyl cellulose. SEM images suggested that the cross-section of freeze-dried hydrogels was porous. The data of adsorption and release experiments for two model drugs suggest that the controlled drug release can be achieved.     

Radiation synthesis of graphene oxide/composite hydrogels and their ability for potential dye adsorption from wastewater

A high yield of graphene oxide (GO) was chemically synthesized from graphite powder utilizing adjusted Hummer's method. The contents of acidic functional groups in GO were determined using potentiometric titration. Composite hydrogels dependent on graphene oxide/poly(2-acrylamido-2-methylpropanesulfonic acid)/polyvinyl alcohol (GO/PAMPS/PVA) were synthesized utilizing a ⁶⁰Co gamma irradiation source at different doses. The synthesized graphene oxide and composite hydrogels were portrayed via X-ray diffraction, thermogravimetric analysis, and Fourier transform infrared analysis. The morphology of composite hydrogels was characterized by scanning electron microscope. The gel % and swelling % for the prepared hydrogel demonstrated that the swelling % of hydrogel increased with raising AMPS content. Whereas the increment of GO and increasing the irradiation dose lead to a reduction in the swelling %. The influences of pH, GO percentage, initial dye concentration, the adsorbent dosage, contact time, and temperature on the adsorption of basic blue 3 dye were evaluated and the adsorption capacity was 194.6 mg/g at optimum conditions; pH = 6, GO/PAMPS/PVA composite hydrogels with 5 wt% of GO, initial dye concentration = 200 mg/L, adsorbent dose = 0.1 g, solution volume = 50 mL after 360 min at room temperature (25°C). The adsorption of dye onto the GO/PAMPS/PVA composite hydrogels follows Pseudo-second-order adsorption kinetics, fits the Freundlich adsorption isotherm model.     

Removal of paraquat pesticide from aqueous solutions using a novel adsorbent material based on polyacrylamide and methylcellulose hydrogels

This research studied the characteristics of poly(acrylamide) and methylcellulose (PAAm‐MC) hydrogels as a novel adsorbent material for removal of pesticide paraquat, from aqueous solution, with potential applications in curbing environmental risk from such herbicides. PAAm‐MC hydrogels with different acrylamide (AAm) and MC concentrations were prepared by a free‐radical polymerization method. The capability of the hydrogels in removing paraquat dichloride from aqueous solution was determined using UV–Vis analysis. The scanning electron microscopy method was used to study the morphological properties of the hydrogels, and swelling degree (Q) of the hydrogels was also measured. The entrapped MC in PAAm chains provoked significant changes in morphological, hydrophilic, and adsorption properties of the PAAm‐MC hydrogels. The adsorption capacity of hydrogels was strongly influenced by AAm, MC, and paraquat concentrations with the highest adsorption capacity (q_eq = 14.3 mg g^?1) was observed for hydrogels synthesized with 6.0% AAm with 0.75% MC swollen in 45.7 mg L^?1 of paraquat solution. Freundlich model performed better than Langmuir model in describing the adsorption isotherm of PAAm‐MC/paraquat system, implying a heterogeneous surface. These results suggest that PAAm‐MC hydrogels are potentially viable absorbents for removal of paraquat pesticide from aqueous solution and cleaning water contaminated with dyes, heavy metals, and others pesticides. © 2009 Wiley Periodicals, Inc. Journal of Appl Polym Sci, 2009     

The effect of gel composition on the uranyl ions adsorption capacity of poly(N‐vinyl 2‐pyrrolidone‐g‐citric acid) hydrogels prepared by gamma rays

Poly(N‐vinyl 2‐pyrrolidone‐g‐citric acid) (PVP‐g‐CA) hydrogels with varying compositions were prepared from ternary mixtures of N‐vinyl 2‐pyrrolidone–citric acid–water by using ⁶⁰Co γ‐rays. The effect of gel composition on the uranyl ions adsorption capacity of PVP‐g‐CA hydrogels was investigated. Uranyl adsorption capacity of these hydrogels were found to be in the range of 18–144 mg [UO]/g dry gel from the aqueous solution of uranyl nitrate and 22–156 mg [UO]/g dry gel from the aqueous solution of uranyl acetate, depending on the content of citric acid in the hydrogel, while poly(N‐vinyl 2‐pyrrolidone) hydrogel did not sorb any uranyl ion. The swelling of PVP‐g‐CA hydrogel containing 2.7 mol % CA was observed in water (1620%), in uranyl acetate solution (1450%) and in uranyl nitrate solution (1360%), as compared to 700% swelling of pure PVP hydrogels. The diffusion coefficients were varied from 12.57 up to 4.04 • 10⁻⁸ m² s⁻¹. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1037–1043, 2000     

Pectin‐[(3‐acrylamidopropyl) trimethylammonium chloride‐co‐acrylic acid] hydrogel prepared by gamma radiation and selectively silver (Ag) metal adsorption

Pectin‐[(3‐acrylamidopropyl) trimethylammonium chloride‐co‐acrylic acid] hydrogel has been prepared from the aqueous blend solution of pectin, (3‐acrylamidopropyl) trimethylammonium chloride (APTAC), and acrylic acid (AAc) by applying gamma radiation of different doses (1–25 kGy) from ⁶⁰Co gamma source. The hydrogels were characterized by equilibrium swelling, Fourier transform infrared, differential scanning calorimetry, and scanning electron microscopy. The hydrogels were used in multielement adsorption and it was found that pectin‐(APTAC‐co‐AAc) gel is highly selective toward silver (I) ion among 27 metal ions. The data obtained from equilibrium adsorption studies were fitted in Langmuir and Freundlich adsorption isotherm models and model parameters evaluated. The maximum adsorption capacity of pectin‐(APTAC‐co‐AAc) gel was found to be 67.6413 mg/g of dry gel at sample volume of 25 mL. The kinetic data were tested using pseudo‐first order and pseudo‐second order kinetic models and different adsorption diffusion models such as film diffusion and intra‐particle diffusivity model. Thiourea solution was used for desorption of adsorbed metal ions from the hydrogel. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45906.     

Alcohophilic gels: Polymeric organogels composing carboxylic and sulfonic acid groups

Polymeric organogels based on acrylic acid (AA) and sodium allyl sulfonate (SAS) were prepared through solution polymerization using a persulfate initiator and a polyethylene glycol diacrylate (PEGDA) crosslinker. FTIR spectroscopy, elemental, and rheological analyses were used for a preliminary characterization. Thermo‐mechanical analysis was also carried out for characterizing samples. Glass transition temperature (T_g) of copolymer was decreased after acid treatment which could be attributed to detachment of ion pairs during the post‐treatment. Due to counterion binding of Na⁺ to form ionomer, the poly(AA‐SAS) gels showed no polyelectrolyte behavior to have high swelling capacity in conventional alcohols, i.e., ethanol and methanol. It was postulated that modification via removing Na⁺ could help breaking ion pair aggregates which leads to swelling enhancement. Thus, poly(AA‐SAS) was treated with hydrochloric acid to remove (Na⁺) counterions. This modification led to the gel transform from ionomer regime to a polyelectrolyte regime in which free mobile ions were existed in the network. The gel swelling capacity was increased due to raise of mobile ions after the treatment. It was found that both of the acid concentration and treatment time had constructive influence on the gel alcohophilicity. The acid‐treated samples could imbibe ethanol and methanol as high as 25.8 and 39.5 g/g, respectively. They may be superior candidates for applications such as pharmaceuticals gels and fire starters. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Removal of heavy metals from model wastewater by using carboxymehyl cellulose/2‐acrylamido‐2‐methyl propane sulfonic acid hydrogels

A series of functional copolymer hydrogels composed of carboxymethyl cellulose (CMC) and 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) were synthesized using γ‐radiations‐induced copolymerization and crosslinking. Preparation conditions were optimized, and the swelling characteristics were investigated. The ability of the prepared hydrogels to recover some toxic metal ions from their aqueous solutions was studied. The prepared hydrogel showed a great capability to recover metal ions such as: Mn⁺², Co⁺², Cu⁺², and Fe⁺³ from their solutions. The data revealed that the chelating ability of the prepared hydrogels is mainly dependent on their internal composition, in addition to the physical properties of the metal ion solution such as pH and metal ion concentration. The data show that the chelating ability of the prepared hydrogels increases by increasing the AMPS content in the hydrogel as well as the increment in the pH of the solution and the metal ion concentration. The prepared CMC/AMPS copolymer hydrogels are chemically stable enough to be reused for at least five times with the same efficiency. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011