A green and facile synthesis of nosean composite from coal fly ash for optimizing Rhodamine B adsorption using response surface methodology

Abstract

• A novel nosean composite is successfully synthesized from coal fly ash via a facile and green approach. • The nosean composite exhibits good performance for RhB adsorption. • Optimal operation parameters for RhB adsorption are obtained by RSM. • Up to 95.9% RhB removal can be obtained at optimum conditions. The study investigated the performance of Rhodamine B adsorption on a novel low-cost nosean composite synthesized from coal fly ash by a microwave-assisted alkali-hydrothermal method. The low-cost nosean composite was characterized with BET, XRD, FTIR, SEM, and zeta potential measurements. Response surface methodology with Central Composite Design was applied to analyze the effects of five parameters including initial dye concentration, adsorbent dosage, initial solution pH, temperature, and contact time on Rhodamine B removal and optimize the adsorption process. The analysis results in terms of coefficient of determination of 0.9586 and adequate precision of 13.16 indicated that the quadratic regression model was statistically significant and the parameters of adsorbent dosage and initial dye concentration profoundly influenced the response (Rhodamine B removal). The maximum Rhodamine B removal of 92.67% was obtained under the optimal conditions as follows. Five adsorption/desorption cycle studies proved the feasibility of reuse of the nosean composite. This study realizes the high-value and environmental utilization of coal fly ash by preparing low-cost nosean composite together with a silica-containing solution with a facile and green approach.