Facile fabrication of chitosan/bone/bamboo biochar beads for simultaneous removal of co-existing Cr(VI) and bisphenol a from water.

Abstract

Heavy metal Cr(VI) and organic BPA have posed harmful risks to human health, aquatic organisms and the ecosystem. In this work, Chitosan/bone/bamboo biochar beads (CS-AMCM) were synthesized by co-pyrolysis and in situ precipitation method. These microbeads featured a particle size of approximately 1 ± 0.2 mm and were rich in oxygen/nitrogen functional groups. CS-AMCM was characterized using XRD, Zeta potential, FTIR, etc. Experiments showed that adsorption processes of CS-AMCM on Cr(VI) and BPA fitted well to Langmuir model, with theoretical maximum capacities of 343.61 mg/g and 140.30 mg/g, respectively. Pore filling, electrostatic attraction, redox, complexation and ion exchange were the main mechanisms for Cr(VI), whereas for BPA, the intermolecular force (hydrogen bond) and pore filling were involved. CS-AMCM with adsorbed Cr(VI) demonstrated effective activation in producing ·OH and ·O₂ from H₂O₂, which degraded BPA and Cr(VI) with the removal rates of 99.2% and 98.2%, respectively. CS-AMCM offers the advantages of low-cost, large adsorption capacity, high catalytic degradation efficiency, and favorable recycling in treating Cr(VI) and BPA mixed wastewater, which shows great potential in treating heavy metal and organic matter mixed pollution wastewater.