School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China; Key Laboratory of Effective Utilization of Agricultural Water Resources of Ministry of Agriculture, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China; Heilongjiang Provincial Key Laboratory of Water Resources and Water Conservancy Engineering in Cold Region, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China.
School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China; Key Laboratory of Effective Utilization of Agricultural Water Resources of Ministry of Agriculture, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China; Heilongjiang Provincial Key Laboratory of Water Resources and Water Conservancy Engineering in Cold Region, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China.
J Environ Manage. 2024 Dec;371:123246. doi: 10.1016/j.jenvman.2024.123246. Epub 2024 Nov 13.
Heavy metal contamination of agricultural land due to sewage irrigation, over-application of fertilizers and pesticides, and industrial activities. Biochar, due to its rich functional groups and excellent electrochemical performance, is used for the remediation of heavy metal-contaminated farmland. However, the remediation mechanism remains uncertain due to the influence of minerals and multi-element composite pollution on soil. Therefore, introducing transition metal oxide MoO to prepare biochar composite remediation materials enhances the adsorption and reduction of soil Cr (Ⅵ). This study compared the differences in Cr (Ⅵ) improvement under different pollution systems and pH conditions and explored the potential mechanism of Fe (Ⅲ)/Fe (Ⅱ) redox cycling in Cr (Ⅵ) remediation. The results showed that both biochar MoO ball-milling composite (BC + M) and biochar-loaded MoO (BC/M) retained the original biochar (BC) remediation method for Cr (Ⅵ). Among them, the remediation of BC/M was the most stable, with the maximum remediation value ranging from approximately 6.52 to 58.58 mg/kg. In different pollution systems, Cd and Pb exhibited competitive adsorption toward Cr (Ⅵ), but they enhanced Cr (Ⅵ) remediation by promoting adsorption and self-complexation. In acidic conditions (pH = 4), BC/M showed the best remediation effect, with a reduction kinetic constant of 34.61 × 10 S and a maximum adsorption capacity of 61.64 mg/g. Fe (Ⅲ)/Fe (Ⅱ) redox cycling accelerated the reduction of Cr (Ⅵ) (R = 0.81), and MoO promoted the Fe (Ⅲ)/Fe (Ⅱ) redox cycle. BC/M enhanced the Fe (Ⅱ) formation efficiency by 66.39% and 71.81% compared to BC + M and BC at pH = 4. The introduction of MoO and biochar composite materials enhanced the reduction process of Cr (Ⅵ), with BC/M achieving the optimal remediation level. This study reveals the potential mechanisms of MoO and biochar composite materials in soil Cr (Ⅵ) remediation, providing a reference and insight for the preparation of Cr (Ⅵ) remediation materials and the treatment of contaminated farmland.
由于污水灌溉、化肥和农药过度施用以及工业活动，农业用地受到重金属污染。生物炭由于其丰富的官能团和优异的电化学性能，被用于修复重金属污染农田。然而，由于矿物质和多元素复合污染对土壤的影响，修复机制仍不确定。因此，引入过渡金属氧化物 MoO 来制备生物炭复合修复材料，增强了土壤 Cr（Ⅵ）的吸附和还原。本研究比较了不同污染体系和 pH 条件下 Cr（Ⅵ）改善的差异，探讨了 Fe（Ⅲ）/Fe（Ⅱ）氧化还原循环在 Cr（Ⅵ）修复中的潜在机制。结果表明，生物炭 MoO 球磨复合材料（BC+M）和负载 MoO 的生物炭（BC/M）均保留了原始生物炭（BC）对 Cr（Ⅵ）的修复方法。其中，BC/M 的修复效果最稳定，最大修复值范围在 6.52 到 58.58mg/kg 之间。在不同的污染体系中，Cd 和 Pb 对 Cr（Ⅵ）表现出竞争吸附，但它们通过促进吸附和自络合来增强 Cr（Ⅵ）的修复。在酸性条件（pH=4）下，BC/M 表现出最佳的修复效果，还原动力学常数为 34.61×10S，最大吸附容量为 61.64mg/g。Fe（Ⅲ）/Fe（Ⅱ）氧化还原循环加速了 Cr（Ⅵ）的还原（R=0.81），MoO 促进了 Fe（Ⅲ）/Fe（Ⅱ）氧化还原循环。与 BC+M 和 BC 相比，BC/M 使 Fe（Ⅱ）的形成效率提高了 66.39%和 71.81%。MoO 和生物炭复合材料的引入增强了 Cr（Ⅵ）的还原过程，BC/M 达到了最佳的修复水平。本研究揭示了 MoO 和生物炭复合材料在土壤 Cr（Ⅵ）修复中的潜在机制，为 Cr（Ⅵ）修复材料的制备和污染农田的处理提供了参考和见解。
