TM-SiO2 cross-linked dual-network hydrogel for efficient removal of methylene blue from complex wastewater

Abstract

The environmental issues caused by industrial wastewater have prompted wastewater purification to become a significant area of academic research. In this paper, 2-Acrylamide-2-methylpropanesulfonic acid (AMPS) and sodium carboxymethyl cellulose (CMC) were used as double anionic monomers, and vinyl-modified silica (STS) was used as nanofiller and crosslinker to construct nanocomposite double-network (DN) hydrogels AMPS/CMC/STS. The material exhibited an ultra-high adsorption capacity (Q_e = 4595 mg/g) and rapid adsorption characteristics (90 % of the equilibrium adsorption capacity within 5 min) for MB (500 mg/L). It maintained a high adsorption capacity under extreme pH (2–11) and in the presence of metal ions due to the significant stability of the dense network structure constructed by the nano-crosslinker and DN structure. Kinetic and thermodynamic analyses indicated that the adsorption process followed quasi-second-order kinetics and the Langmuir isotherm model, confirming that it was dominated by monolayer chemisorption. The absorbent could complete four cycles after acid washing and desorption. Furthermore, the adsorption capacity in simulated natural water bodies (Tap water, Minjiang River water, Guihu Lake water, and Pihe River water) and simulated in real wastewater remained stable at over 3248 mg/g, highlighting its potential application in complex industrial wastewater treatment.