INVESTIGATING THE INFLUENCE OF MICROWAVE-ASSISTED PYROLYSIS PARAMETERS ON ADSORPTION CHARACTERISTICS OF BIOCHAR

Abstract

Growing attention to environmental sustainability and circular economy practices has promoted the valorization of agricultural and industrial by-products for resource-efficient waste management. This research converts Brewer’s Spent Grain (BSG), a lignocellulosic biomass waste constituting nearly 85% of brewing industry waste, into functional biochar (BC) as an adsorbent for dye removal from water. Microwave-Assisted Pyrolysis (MAP) was used to prepare BSG-BC, and microwave power, irradiation time, and H3PO4 concentration were optimized using Box-Behnken Design (BBD) and Response Surface Methodology (RSM). Characterization (FTIR, SEM, BET, CHNS, TGA) confirmed improved porosity, surface area, and functional groups; the optimized biochar showed thermal stability and BET surface area ~502.9 m2/g. Adsorption experiments with Crystal Violet (CV) and Orange-II (Or-II) showed PSO kinetics (R2>0.99) and Freundlich/Redlich-Peterson isotherms (R2=0.96–0.99), with capacities of 53.28 mg/g (CV) and 46.97 mg/g (Or-II). Fixed-bed columns agreed with batch results, supporting BSG-BC for batch and continuous wastewater treatment.