Wu Han, Liu Linan, Sun Jingmin, He Xin, Li Zichuan, Tang Jingchun
MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Hebei Provincial Key Laboratory of Agroecological Safety, Hebei University of Environmental Engineering, Hebei 066102, China.
J Hazard Mater. 2025 Aug 15;494:138702. doi: 10.1016/j.jhazmat.2025.138702. Epub 2025 May 21.
Biochar-based remediation can reduce Cd pollution through adsorption but may potentially increases As accumulation in rice grains by microbial reduction. Therefore, developing materials that simultaneously immobilize Cd and inhibit As translocation to plants is crucial for co-contamination management. Iron-silicon modified biochar (Fe/Si-BC) was synthesized and evaluated in pot experiments for remediation of Cd/As co-contamination. The results demonstrated that Fe/Si-BC significantly reduced Cd accumulation in rice grains by up to 81.12 %. Mantel test and random forest importance analyses revealed that Fe and dissolved Si introduced by Fe/Si-BC were key factors in reducing Cd bioavailability, highlighting the synergistic roles of Fe and Si in increasing remediation efficiency. Notably, Fe/Si-BC exhibited dual effects on As toxicity in rice. Specifically, in the high-pollution soils, 0.35 % Fe/Si-BC significantly reduced As accumulation in rice grains by 28.21 %. In contrast, the 1.0 % Fe/Si-BC slightly increased As accumulation in rice grains. Unfortunately, Fe/Si-BC increased the risk of As release into soil porewater. Further analysis revealed that Fe/Si-BC promoted the formation of iron plaques, which possessed a pronounced affinity for As, thereby substantially diminishing As uptake by rice roots. Overall, this study highlights the potential of Fe/Si-BC for the remediation of Cd/As co-contaminated paddy soils, while emphasizing the need for application to manage As mobility risks.
基于生物炭的修复可以通过吸附作用减少镉污染，但可能会因微生物还原作用而增加水稻籽粒中砷的积累。因此，开发能够同时固定镉并抑制砷向植物体内转移的材料对于联合污染治理至关重要。合成了铁硅改性生物炭（Fe/Si-BC），并通过盆栽试验评估其对镉/砷联合污染的修复效果。结果表明，Fe/Si-BC可使水稻籽粒中的镉积累量显著降低，降幅高达81.12%。Mantel检验和随机森林重要性分析表明，Fe/Si-BC引入的铁和溶解态硅是降低镉生物有效性的关键因素，突出了铁和硅在提高修复效率方面的协同作用。值得注意的是，Fe/Si-BC对水稻中砷的毒性表现出双重影响。具体而言，在高污染土壤中，0.35%的Fe/Si-BC可使水稻籽粒中的砷积累量显著降低28.21%。相比之下，1.0%的Fe/Si-BC则略微增加了水稻籽粒中的砷积累量。遗憾的是，Fe/Si-BC增加了砷向土壤孔隙水释放的风险。进一步分析表明，Fe/Si-BC促进了铁膜的形成，铁膜对砷具有显著的亲和力，从而大幅减少了水稻根系对砷的吸收。总体而言，本研究突出了Fe/Si-BC在修复镉/砷联合污染稻田土壤方面的潜力，同时强调了在管理砷迁移风险方面应用的必要性。
