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.

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Synthesized N -(4-bromophenyl)-2-methacrylamide (BrPMAAm) and N -(4-fluorophenyl)-2-methacrylamide (FPMAAm) monomers were polymerized via free radical polymerization. Montmorillonite-containing raw clay (NaMT) was purified to obtain pristine clay (SMT). XRF results of the SMT sample showed that sodium amount increased and so it is sodium montmorillonite. Using the SMT and organic surfactant hexadecyltrimethylammonium bromide (CTAB), organoclay (OSMT) was synthesized. d 001 interlayer distances were 1.4967 nm and 2.0439 nm for SMT and OSMT, respectively. Composites of BrPMAAm and FPMAAm monomers were obtained using 2%, 4%, 6%, and 10% organoclay by in situ polymerization. Molecular weights for poly(BrPMAAm), poly(BrPMAAm)-10%OSMT, poly(FPMAAm), and poly(FPMAAm)-10%OSTM were 91,300, 31,300, 17,400, and 23,700, respectively. Thermal properties of the nanocomposite were also developed when compared to the pure homopolymer. The beginning thermal decomposition temperature of nanocomposites was shifted to higher temperature. An exfoliated structure was found for the nanocomposites.

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