Immobilization performance of graphene oxide-based engineered biochar derived from peanut shell towards cationic and anionic dyes

Abstract

Water pollution due to variety of organic contaminants is a serious global threat due to its adverse effects on aquatic life, terrestrial organisms and environment. In this sense, sustainable wastewater treatment using materials derived from lignocellulosic wastes has received considerable scientific attention because they are abundant, low-cost and functional-group rich. In this work, a facile approach has been demonstrated to design peanut shell biochar-graphene oxide (PBC@GO)-based binary composite. Herein, PBC@GO composite was fabricated and assessed as an adsorptive platform for cationic and anionic dyes viz. Crystal Violet (CV) and Bromophenol Blue (BPB), respectively, as model pollutants. The test materials were characterized by means of SEM, FTIR, XRD and TGA. The influence of pH, time, dosage and concentration of model pollutants was ascertained for optimal performance in batch mode. Results showed that PBC@GO efficiently removed CV (97 %) and BPB (87 %), whilst kinetic data accorded well with pseudo-second-order model with R2 values of 0.97 and 0.99 for CV and BPB, respectively. Moreover, equilibrium data was fitted to the Langmuir and Freundlich models to understand sorption mechanism for CV and BPB dyes. Comparative study showed synergistic effects of PBC and GO in terms of better removal efficiency due to the availability of multi-interaction sites in PBC@GO composite as compared to the precursors. Apart from superior pollutant's uptake ability, high % recoveries obtained by using spiked real water samples as well as long term stability of the prepared composite when subjected to five successive cycle of use without any substantial loss of its ability towards scavenging dyes were crucial for improving sustainability of water treatment systems.