Synthesis and Characterization of Cellulose and IPN (Cellulose/PVA) Hydrogels and Their Application in Dye Retention

The discharge of dye-contaminated effluents from textile industries into water bodies poses a severe threat to aquatic ecosystems and human health. To address this challenge, cellulose and interpenetrating polymer network (IPN) hydrogels based on cellulose and poly(vinyl alcohol) (PVA) were developed via an in situ synthesis method. The cellulose solution was obtained by cold dissolving the polysaccharide in NaOH, then dissolving PVA. The IPN hydrogels were obtained by co-cross-linking the two polymers in an alkaline medium using ECH. To optimize the hydrogels, synthesis parameters like time (4-7 h), temperature (50-80 °C), and cross-linking ratio (ECH = 50-125% <i>w</i>/<i>w</i>) were varied. Different hydrogel compositions (Cel/PVA = 90/10 to 60/40 <i>w</i>/<i>w</i>) were tested for their absorption efficiency in removing Tubantin Blue (DB 78) dye under varying initial concentrations and temperatures. Hydrogels exhibit varying adsorption capacities for DB78, depending on their IPN composition, synthesis parameters, and dye concentration. Specifically, IPN adsorption capacity ranges from 8.8 to 38.1 mg DB78/g hydrogel (7.5-36.2% efficiency). At high effluent concentrations, IPN can reach a retention capacity of 217.7 mg/g, achieving a retention efficiency of 58.4%. Cellulose and cellulose/PVA IPN hydrogels show promise as sustainable adsorbents for treating dye-contaminated wastewater.