Eco-friendly adsorption of a cationic dye using a chemically modified industrial by-product: process optimization and modeling

Abstract

The increasing environmental threat posed by dye-contaminated wastewater, particularly from textile industries, calls for the development of effective and economically viable treatment solutions. Adsorption has emerged as a promising method due to its straightforward application, enhanced efficiency, and economic feasibility. In this study, an industrial by-product from sweet almond oil extraction (sweet almond, SA) was chemically modified with hydrogen peroxide (H₂O₂) to produce an innovative adsorbent material, noted SA-OH, for the removal of Basic Blue 41 (BB41) dye from aqueous solutions. The SA and SA-OH materials were characterized using scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) to investigate their morphological and surface properties. The operational parameters affecting BB41 removal, including solution pH, adsorbent dosage, and initial dye concentration, were optimized using central composite design (CCD) within the framework of the response surface methodology (RSM). Isotherm and kinetic models were applied to describe the biosorption behavior. The results indicated a substantial improvement in the adsorption capacity of SA-OH compared to untreated SA, demonstrating the potential of SA-OH as an effective, cost-efficient, and environmentally sustainable adsorbent for industrial wastewater treatment. To the best of our knowledge, this is the first study reporting the use of hydrogen peroxide-modified sweet almond waste for BB41 dye removal.