School of Metallurgy and Environment, Central South University, Changsha 410083, PR China.
School of Metallurgy and Environment, Central South University, Changsha 410083, PR China.
Sci Total Environ. 2019 Jan 10;647:1158-1168. doi: 10.1016/j.scitotenv.2018.08.087. Epub 2018 Aug 7.
Cadmium contamination in paddy soils has aroused increasing concern around the world, and biochar has many positive properties, such as large specific surface areas, micro porous structure for the heavy metal immobilization in soils. However there are few studies on sulfur-iron modified biochar as well as its microbiology effects. The purpose of this study was to evaluate the Cd immobilization effects of sulfur or sulfur-iron modified biochar and its related microbial community changes in Cd-contaminated soils. SEM-EDX analysis confirmed that sulfur and iron were loaded on the raw biochar successfully. Sulfur-modified biochar (S-BC) and sulfur-iron modified biochar (SF-BC) addition increased pH value and the content of soil organic matter, and also decreased DTPA-extractable Cd. There was a negative significant correlation between organic matter content and the available Cd (P < 0.05). During a 45-d incubation period, the fractions of Cd are mainly with the exchangeable (25.16-35.79%) and carbonate (22.01-25.10%) fractions. Compared with the control, the concentrations of exchangeable Cd in soil were significantly (P < 0.05) decreased by 12.54%, 29.71%, 18.53% under the treatments of BC, S-BC, SF-BC respectively. The S-BC and SF-BC treatments significantly (P < 0.05) increased Chao1, observed, Shannon and Simpson diversity indices compared with the control and biochar treatments. Meanwhile, the relative abundance of Proteobacteria, Bacteroidetes, and Actinobacteria increased, whereas the abundance of Acidobacteria and Germmatimonadetes decreased. Capsule: Sulfur-modified and sulfur-iron modified biochar applications decreased the available Cd and changed the microbial community.
镉污染在稻田土壤中引起了全世界的关注，生物炭具有许多积极的特性，如大的比表面积、微孔结构，可用于固定土壤中的重金属。然而，关于硫铁改性生物炭及其微生物学效应的研究较少。本研究旨在评估硫或硫铁改性生物炭对镉污染土壤中镉的固定效果及其相关微生物群落的变化。SEM-EDX 分析证实硫和铁成功地负载在原始生物炭上。添加硫改性生物炭（S-BC）和硫铁改性生物炭（SF-BC）提高了土壤 pH 值和有机质含量，同时降低了 DTPA 可提取镉的含量。有机质含量与有效镉呈负显著相关（P<0.05）。在 45 天的培养期内，镉的形态主要为可交换态（25.16-35.79%）和碳酸盐结合态（22.01-25.10%）。与对照相比，BC、S-BC 和 SF-BC 处理分别使土壤中可交换态镉的浓度显著（P<0.05）降低了 12.54%、29.71%和 18.53%。与对照和生物炭处理相比，S-BC 和 SF-BC 处理显著（P<0.05）增加了 Chao1、Observed、Shannon 和 Simpson 多样性指数。同时，变形菌门、拟杆菌门和放线菌门的相对丰度增加，而酸杆菌门和芽单胞菌门的丰度减少。结论：硫改性和硫铁改性生物炭的应用降低了有效态镉的含量，并改变了微生物群落。
