Extraction of silica and biochar from biomass waste for the synthesis of aerogel and its application for the removal of dye

Abstract

Contamination o f wastewater is one of the rising global issues, and several studies are being conducted to perform efficient treatment processes with cost-effective methods. In this study, sugarcane bagasse was used as biomass to extract silica (Si) and biochar (BC) and was used further as fillers for aerogel formation with polyvinyl alcohol (PVA) polymer to eliminate Congo red dye from the solution. A batch study was conducted in each case, and the efficiency of dye removal, by different aerogel PVA, PVA-Si, and PVA-BC was studied. Experimental parameters were varied to analyze the effect of the various parameters in each case. The highest removal was 94.98% using PVA-Si aerogel at 300 min with 10 mg/L initial concentration of Congo red, pH 7, and temperature 30 ℃. The adsorption capacity of Congo red was 29.49 mg/g by PVA-Si aerogel. The characterization of the aerogel showed the occupancy of various functional groups, modification in crystallographic structure, and surface alteration of aerogels. The analysis for the study of kinetics exhibited that the process of adsorption fitted the pseudo-second-order reaction for all the aerogels and also the thermodynamics data demonstrated that the adsorption process was spontaneous and endothermic. Also, from the isotherm modeling, it was observed that the process best fitted with the Freundlich isotherm model.