Tan Wen-Tao, Zhou Hang, Tang Shang-Feng, Chen Qiong, Zhou Xia, Liu Xin-Hui, Zeng Peng, Gu Jiao-Feng, Liao Bo-Han
College of Environment Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
College of Environment Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China; Hunan Engineering Laboratory for Control of Rice Quality and Safety, Changsha 410004, China.
Sci Total Environ. 2023 Feb 1;858(Pt 1):159730. doi: 10.1016/j.scitotenv.2022.159730. Epub 2022 Oct 25.
Fe-Mn oxide-modified biochar (BC-FM) was used to remediate Cd-contaminated soil and mitigate Cd accumulation in rice. The roles of Fe and Mn in soil Cd immobilization and in controlling Cd uptake by rice were investigated via X-ray photoelectron spectroscopy (XPS) characterization and chemical analysis. Fe and Mn loaded on BC-FM increased the removal efficiencies of CaCl extractable Cd in soil and Cd in pore water compared to those in only biochar (BC)-treated soil, with maximum removal rates at 67.9 % and 77.8 %, respectively. The XPS results indicated that the redox reactions of the Fe-Mn oxides on BC-FM surface affected Cd immobilization in the soil. The Fe (II/III) components on BC-FM were primarily converted to FeO in the soil system, which may form stable complexes with Cd (Fe-O-Cd) during the entire rice growth period, and Cd may be bound to MnO or MnO in the form of CdMnO. The excellent adsorption performance of BC-FM enhanced by Fe-Mn oxides reduced the available Cd in the soil and stimulated Fe and Mn transport in rice, thereby inhibiting Cd accumulation in the aerial parts of rice. Cd concentrations in brown rice under BC-FM treatments reached the national safety standard (0.2 mg/kg, GB2762-2017). And BC-FM significantly increased the biomass of brown rice with a maximum rate of 26.8 %. These findings suggest that BC-FM could be used as an efficient material for Cd-contaminated soil remediation, and Fe-Mn plays important role in immobilizing Cd in soil and reducing Cd transport in rice.
铁锰氧化物改性生物炭（BC-FM）被用于修复镉污染土壤并减轻水稻中的镉积累。通过X射线光电子能谱（XPS）表征和化学分析，研究了铁和锰在土壤镉固定以及控制水稻对镉吸收方面的作用。与仅用生物炭（BC）处理的土壤相比，负载在BC-FM上的铁和锰提高了土壤中氯化钙可提取镉以及孔隙水中镉的去除效率，最大去除率分别为67.9%和77.8%。XPS结果表明，BC-FM表面铁锰氧化物的氧化还原反应影响了土壤中镉的固定。BC-FM上的铁（II/III）组分在土壤系统中主要转化为FeO，在整个水稻生长期间可能与镉形成稳定的络合物（Fe-O-Cd），并且镉可能以CdMnO的形式与MnO或MnO结合。铁锰氧化物增强了BC-FM的优异吸附性能，降低了土壤中有效镉的含量，并促进了水稻中铁和锰的运输，从而抑制了水稻地上部分的镉积累。BC-FM处理下糙米中的镉浓度达到了国家安全标准（0.2 mg/kg，GB2762-2017）。并且BC-FM显著提高了糙米的生物量，最大增长率为26.8%。这些研究结果表明，BC-FM可作为镉污染土壤修复的有效材料，铁锰在固定土壤中的镉以及减少水稻中镉的运输方面发挥着重要作用。
