As a porous material, biochar has been endowed with high expectations to be the carrier for heavy metals-tolerant microorganism loading due to its excellent performance. Therefore, the biochar derived from green walnut husk was used in this study to load a screened heavy metal-tolerant organic phosphorus-degrading bacteria OPB3–6–1 for heavy metals remediation. The results suggested that biochar loaded with OPB3–6–1 (IOPB) exhibited a synergistic effect in adsorbing of Pb, Cu and Cd, while IOPB500 (carrier prepared under 500℃ of pyrolysis temperature) obtained the highest adsorption potential as its adsorption capacities for Pb, Cu and Cd reached 591.0, 300.0 and 20.0 mg/g under a certain initial concentration, respectively. In addition, the carrier dosage, reaction temperature and pH posed different effects on IOPB500 in heavy metals adsorption, and the top adsorption capacity obtained under the condition of 1 g/L of dosage, 30℃ of reaction temperature and 6–7 of pH. The adsorption kinetics and isotherms suggested that monolayer chemical reaction dominated the whole adsorption process of IOPB500 for Pb, Cu and Cd, while intra-particle diffusion process played a greater role in rate control. Compared with intracellular uptake, extracellular complexation accounted for the major contribution for Pb, Cu and Cd adsorption of OPB3–6–1, which facilitated the adsorption of heavy metals in IOPB since such functional groups as PO, P-OH and PO were detected in IOPB by FTIR. After applying IOPB500 into heavy metal contaminated soil, the exchangeable fraction of Pb, Cu and Cd decreased by 15.7%, 19.0% and 23.24%, while the residual content increased by 15.9%, 9.3% and 11.5%, respectively, thereby alleviated the toxicity and risks of heavy metals. Overall, the conclusion of this study proved the potential of biochar-bacteria coupled systems on heavy metal remediation applications.

中文翻译：

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负载有机磷降解菌增强生物炭对重金属的吸附性能

作为一种多孔材料，生物炭因其优异的性能而被赋予作为耐重金属微生物负载的载体的寄予厚望。因此，本研究采用源自绿核桃壳的生物炭负载筛选出的耐重金属有机磷降解菌OPB3-6-1进行重金属修复。结果表明，负载OPB3-6-1（IOPB）的生物炭对Pb、Cu和Cd的吸附表现出协同效应，而IOPB500（在500℃热解温度下制备的载体）获得了最高的吸附潜力，因为其对Pb、Cu和Cd的吸附能力最高。在一定初始浓度下，Pb、Cu和Cd分别达到591.0、300.0和20.0 mg/g。此外，载体用量、反应温度和pH对IOPB500对重金属的吸附有不同的影响，以及在用量1 g/L、反应温度30℃、pH 6~7条件下获得的最高吸附量。吸附动力学和等温线表明，单层化学反应主导了IOPB500对Pb、Cu和Cd的整个吸附过程，而颗粒内扩散过程在速率控制中发挥了更大的作用。与细胞内摄取相比，细胞外络合对 OPB3-6-1 的 Pb、Cu 和 Cd 吸附贡献最大，这促进了 IOPB 中重金属的吸附，因为在 OPB3-6-1 中检测到了 PO、P-OH 和 PO 等官能团。 FTIR 测定的 IOPB。重金属污染土壤施用IOPB500后，Pb、Cu、Cd的可交换分数分别下降了15.7%、19.0%和23.24%，残留含量分别增加了15.9%、9.3%和11.5%，从而减轻了毒性。和重金属的风险。总体而言，本研究的结论证明了生物炭-细菌耦合系统在重金属修复应用中的潜力。