Elaboration of metal (M: Co, Cu, Ni, Fe) embedded poly(acrylic acid-co-acrylamide) hydrogel nanocomposites: An attempt to synthesize uncommon architectured 'Auto-active' nanocatalysts for treatment of dyeing wastewater

摘要

Herein, physicochemical features of poly(acrylic acid-co-acrylamide) hydrogels were studied via swelling, SEM, TGA, DTA and thermoporometric measurements as well Monte-Carlo simulations. Physicochemical characteristics of metal-embedded hydrogel nanocomposites were investigated by ICP-OES, XRD, SEM/EDX and HRTEM analysis. Catalytic behaviour of nanocomposites was examined through multi-repetitive oxidative degradation of methylene blue (MB) from wastewater. Decay of MB concentrations was followed up kinetically by UV-vis spectrophotometer and TOC analyzer. Poly(acrylic acid-co-acrylamide) hydrogels are promising candidates for embedding diverse-shaped nano-sized metallic species (Co, Cu, Ni and Fe) with advanced protectiveness behaviour against deactivation during degradation processes. Surface-sited nanometals developed pseudo-first ordered degradation profiles with inferior reusability trends. Bulk-sited nanometals exhibited strong tendency towards MB mineralization, obeying pseudo-second ordered progression. Hydrogel embedding nickel nanocomposite served as typical "Auto-active" catalyst regarding to its ability to gather reactants and radicals beneath nanometallic particles deep inside monolithics, thereby preserving the reduced metallic form throughout the degradation processes. (C) 2015 Elsevier Ltd. All rights reserved.