Cross-Linked Nano-carboxymethylcellulose, Polyacrylamide, and g-Fe2O3-SO3H to a Hydrophobic Linker: An Organic-Inorganic Hybrid Hydrogel for Dye Removal Adsorption

Abstract

The pH-responsive magnetic hydrogel bearing hydrophobic chlorophenyl implants was prepared by cross-linking the as-prepared nanocarboxymethylcellulose crystals (NCMCC), g-Fe2O3-SO3H, and polyacrylamide (PAAmide) to the synthesized hydrophobic bis-amide N,N'-((4-chlorophenyl)methylene) diacrylamide (NNCMDA). g-Fe2O3-SO3H was either the hydrogel magnetizing agent or the solid acid catalyst for linker synthesis. Carboxymethylation of the cotton-derived nanocellulose was modified to give the NCMCC that cross-linked to the g-Fe2O3-SO3H, and PAAmide by NNCMDA to obtain the NCMCC/PAAmide/g-Fe2O3-SO3H/NNCMDA hydrogel. After characterization of the hydrogel by FT-IR, FESEM, TGA, VSM, and XRD, the results of swelling experiments showed a decrease in water absorption and swelling but retained hydrophilic surface of the hydrogel by hosting the hydrophobic cross-linker NNCMDA. Hydrogel revealed good adsorptive dye removal with selectivity to cationic ones, so its adsorption capacity for Methylene blue (MB) and Rhodamine B (RB) were 717.0 mg/g and 61.0 mg/g, respectively. Simultaneous entering of hydrophobic NNCMDA implants and pH-responsive magnetizing agent g-Fe2O3-SO3H increased the performance of the hydrogel to remove the 74.68% MB and 50.85% RB without matrix change after the fifth recycling run. All resu1ts confirmed that NCMCC/PAAmide/g-Fe2O3-SO3H/NNCMDA hydrogel is an effective adsorbent for the dye removal from wastewater.