INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH, vol.11, pp.557-568, 2017 (SCI-Expanded)
Three different environmentally friendly new composite hydrogels were synthesized and utilized as absorbents for removal of toluidine blue (TB), alizarin red S (AR), and gallocyanine (G) dyes from aqueous media. The homo and co-hydrogels were synthesized via redox polymerization technique from 2-acrylamido-2-methyl-1-propane sulfonic acid sodium salt (AMPS) and 3-acrylamidopropyl-trimethyl ammonium chloride (APTMACl). Polyporus squamosus (Huds.) Fr. [P. squamosus (Huds.) Fr.] fungus was utilized as the bio-part of the composite hydrogels. The effects of pH, contact time, and initial dyes concentrations on the absorption of composite hydrogels were investigated in sequence. It was concluded that Freundlich isotherm model was the best-fitted ones through the computation of the experimentally observed data for common isotherms models such as Freundlich and Langmuir. The maximum absorption of TB by p(AMPS)-P. squamosus (Huds.) Fr., of AR by p(APTMACl)-P. squamosus (Huds.) Fr., and of G by p(APTMACl)-P. squamosus (Huds.) Fr. composite hydrogels were obtained to be 40.9, 31.3, and 36.7 mg/g, respectively. In addition, kinetic studies were carried out for all composite hydrogels and absorbed dyes to obtain the absorption behaviors of studied dyes. They were generally fitted well to a pseudosecond-order kinetic model, while TB dye absorption on the p(AMPS)-P. squamosus (Huds.) Fr. composite hydrogel fitted a pseudofirst-order kinetic model. The obtained data were compared with the literature and it is indicated that absorption capacities of both anionic and cationic composite hydrogels were considerable for utilization.