Remediation of chlorpyrifos and methylene blue dye using biochar-modified Bacillus cell-immobilized alginate beads

Dye and pesticide are highly toxic among the category of organic contaminants. Due to the failure of traditional techniques to provide efficient solution for remediation, alternatives like bioremediation are the hotspot of research by scientists. The modified alginate beads developed in this paper has been utilized for the degradation of chlorpyrifos and methylene blue. The alginate beads were primarily formed with the help of extrusion method and were modified with woodchar. Bacillus cereus strain EBCH14 was encapsulated in the beads. The final modified bead underwent SEM analysis and the elemental composition revealed the presence of carbon and phosphorus which indicated the adsorption potential of the beads and the presence of bacterial cell respectively. The SEM images focused on the abundance of endospores inside the pores of the bead. After carrying out parameter optimization, it was ascertained that these beads can degrade up to 230 mg/L of chlorpyrifos and 120 mg/L of dye. The degradation kinetics showed that considerable amount of contaminants were removed within 12 days and the half-life of the contaminants in the experimental flasks were quite low compared to the controls. GCMS proved that simple alkanes, fatty acids, or plant derivatives were present in the final products, and hence, it is assumed that the degraded products are less hazardous than their parent counterparts. The COD of both contaminants reduced by 90% at the end of 12th day. Thus, the developed encapsulated beads are efficient in degrading substantial amounts of both methylene blue and chlorpyrifos.