Pseudomonas stutzeri Immobilized Sawdust Biochar for Nickel Ion Removal

Nickel ions generated from the electroplating industry and stainless steel and battery manufacturing industries contribute to water pollution, harm human health, and pose environmental risks. A long-term, sustainable, and efficient treatment method should be developed to address this issue. Bioremediation in the presence of biochar and microorganisms is a potential approach for metal ion abatement. This study evaluates the feasibility of Pseudomonas stutzeri immobilized sawdust biochar (PSDB) for Ni2+ removal. Sawdust biochar was prepared by pyrolyzing in a muffle furnace and was characterized using SEM, FTIR, and BET. The influence of biochar preparation parameters such as pyrolysis temperature, time on biochar yield, and impact on cell immobilization was investigated. The effect of various parameters, such as incubation time, pH, temperature, and biocatalyst dosage, was studied. The total Ni2+ in solution was analyzed using inductively coupled plasma optical emission spectrometry. PSDB showed an 83% Ni2+ removal efficiency and reusability up to three cycles. FT-IR analysis revealed that the mechanism of Ni2+ removal by PSDB was the synergistic effect of adsorption by biochar and bioaccumulation by P. stutzeri. This study presents a novel approach for environmental application by utilizing waste biomass-derived biochar as a carrier support for bacteria and an adsorbent for pollutants.