The butyl xanthate (BX) in mining wastewater poses significant environmental challenges due to its toxicity and persistence. This study aimed to evaluate the effectiveness of Pseudomonas sp. immobilized on yak dung biochar (Ps.@YDBC600) for BX degradation, emphasizing the synergistic effects of biochar adsorption and microbial degradation. BX removal efficiency of free Pseudomonas sp. cells was assessed under various environmental conditions, with optimal degradation observed at 30°C and an initial pH of 5.0. Yak dung biochar prepared at 600°C (YDBC600) was selected due to its high surface area, porosity, and favorable adsorption properties, enhancing the immobilization and activity of Pseudomonas sp.. The absorption of BX by biochar followed a two-compartment first-order kinetic model and primarily involved hydrogen bonding, hydrophobic interactions, and pore filling. The primary crystalline mineral component of YDBC600 and Ps.@YDBC600 before and after the adsorption and degradation of BX was SiO₂. The Ps.@YDBC600 was shown to significantly enhance BX removal efficiency compared to free Pseudomonas sp. cells or biochar alone. Molecular studies indicated that biochar facilitated BX degradation by providing a stable environment for Pseudomonas sp. and optimizing metabolic resource allocation. The primary by-products, including CS₂, HS–, ROCOS–, ROCSSH and (ROCSS)₂ were effectively minimized (each by-product was reduced more than 80%), reducing secondary pollution. These findings demonstrated the potential of Pseudomonas sp. immobilized on biochar as an effective approach for treating BX-contaminated mining wastewater, offering a sustainable approach to environmental remediation and management.
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