Mercerized Microcrystalline Cellulose: A Game-Changer for Sustainable Chromium Removal from Tannery Effluents

Abstract

The leather tanning industry generates significant environmental impacts due to the release of effluents containing high concentrations of heavy metals, particularly chromium (Cr). This study investigates the efficacy of mercerized microcrystalline cellulose particles (MCPs) as a sustainable adsorbent for Cr removal from tannery effluents. MCPs were synthesized and characterized using Raman spectroscopy and scanning electron microscopy (SEM) to assess their structural modifications post-mercerization. Adsorption assays were conducted under various experimental conditions, including agitation rate, pH, temperature, effluent concentration, and MCP concentration. The adsorption capacity was modeled using Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherms, with Langmuir providing a better fit (R² = 0.9884), indicating indicating a monolayer adsorption of Cr ions onto the MCPs surface. Results showed a maximum adsorption capacity of 28.17 mg/g for Cr, with optimal conditions identified as 400 rpm agitation, pH 5.0, 35 °C temperature, and 25 mg/L MCP concentration. Multiple regression analysis highlighted pH and effluent dilution as significant factors affecting adsorption efficiency. Additionally, cluster analysis and Detrended Correspondence Analysis (DCA) confirmed the complex interactions among the variables. Our findings suggest that mercerized MCPs are a promising and sustainable solution for Cr removal from tannery effluents, offering a high adsorption capacity and potential for environmental application. Future research should focus on the regeneration and reuse of MCPs, assessing other pollutants, and the economic feasibility of large-scale implementation.