Xiao Nai-Chuan, Wang Zi-Fang, Yang Wen-Na, Xie Yong-Hong, Dai Wen-Cai, Gao Ming
College of Resources and Environment, Southwest University, Chongqing 400715, China.
Fruit Research Institute, Chongqing Academy of Agricultural Sciences, Chongqing 401329, China.
Huan Jing Ke Xue. 2024 May 8;45(5):3027-3036. doi: 10.13227/j.hjkx.202306216.
Biochar and modified biochar have been widely used as remediation materials in heavy metal-contaminated agricultural soils. In order to explore economical and effective materials for the remediation of cadmium (Cd)-contaminated acidic purple soil, distillers 'grains were converted into distillers' grains biochar (DGBC) and modified using nano-titanium dioxide (Nano-TiO) to produce two types of modified DGBCs:TiO/DGBC and Fe-TiO/DGBC. A rice pot experiment was used to investigate the effects of different biochar types and application rates (1%, 3%, and 5%) on soil properties, nutrient content, Cd bioavailability, Cd forms, rice growth, and Cd accumulation. The results showed that:① DGBC application significantly increased soil pH, cation exchange capacity (CEC), and nutrient content, with TiO/DGBC and Fe-TiO/DGBC exhibiting better effects. ② DGBC and modified DGBCs transformed Cd from soluble to insoluble forms, increasing residual Cd by 1.22% to 18.46% compared to that in the control. Cd bioavailability in soil decreased significantly, with available cadmium being reduced by 11.81% to 23.67% for DGBC, 7.64% to 43.85% for TiO/DGBC, and 19.75% to 55.82% for Fe-TiO/DGBC. ③ DGBC and modified DGBCs increased rice grain yield, with the highest yields observed at a 3% application rate:30.60 g·pot for DGBC, 37.85 g·pot for TiO/DGBC, and 39.10 g·pot for Fe-TiO/DGBC, representing 1.13, 1.40, and 1.44 times the control yield, respectively. Cd content in rice was significantly reduced, with grain Cd content ranging from 0.24 to 0.30 mg·kg for DGBC, 0.16 to 0.26 mg·kg for TiO/DGBC, and 0.14 to 0.24 mg·kg for Fe-TiO/DGBC. Notably, Cd content in rice grains fell below the food safety limit of 0.2 mg·kg (GB2762-2022) at 5% for TiO/DGBC and 3% and 5% for Fe-TiO/DGBC. In conclusion, Nano-TiO modified DGBC effectively reduced the bioavailability of soil Cd through its own adsorption and influence on soil Cd forms distribution, thus reducing the absorption of Cd by rice and simultaneously promoting rice growth and improving rice yield. It is a type of Cd-contaminated soil remediation material with a potential application prospect. The results can provide scientific basis for farmland restoration and agricultural safety production of Cd-contaminated acidic purple soil.
生物炭和改性生物炭已被广泛用作重金属污染农田土壤的修复材料。为了探索经济有效的镉（Cd）污染酸性紫色土修复材料，将酒糟转化为酒糟生物炭（DGBC），并用纳米二氧化钛（Nano-TiO₂）进行改性，制备了两种改性DGBC：TiO₂/DGBC和Fe-TiO₂/DGBC。通过水稻盆栽试验，研究了不同类型生物炭及其施用量（1%、3%和5%）对土壤性质、养分含量、Cd生物有效性、Cd形态、水稻生长及Cd积累的影响。结果表明：①施用DGBC显著提高了土壤pH、阳离子交换量（CEC）和养分含量，TiO₂/DGBC和Fe-TiO₂/DGBC效果更佳。②DGBC和改性DGBC使Cd从可溶态转化为不溶态，与对照相比，残渣态Cd增加了1.22%～18.46%。土壤中Cd生物有效性显著降低，DGBC处理下有效态镉降低了11.81%～23.67%，TiO₂/DGBC处理下降低了7.64%～43.85%，Fe-TiO₂/DGBC处理下降低了19.75%～55.82%。③DGBC和改性DGBC提高了水稻籽粒产量，施用量为3%时产量最高：DGBC为30.60 g·盆，TiO₂/DGBC为37.85 g·盆，Fe-TiO₂/DGBC为39.10 g·盆，分别是对照产量的1.13、1.40和1.44倍。水稻中Cd含量显著降低，DGBC处理下籽粒Cd含量为0.24～0.30 mg·kg，TiO₂/DGBC处理下为0.16～0.26 mg·kg，Fe-TiO₂/DGBC处理下为0.14～0.24 mg·kg。值得注意的是，TiO₂/DGBC施用量为5%、Fe-TiO₂/DGBC施用量为3%和5%时，水稻籽粒Cd含量低于食品安全限量0.2 mg·kg（GB2762-2022）。综上所述，纳米TiO₂改性DGBC通过自身吸附作用及对土壤Cd形态分布的影响，有效降低了土壤Cd生物有效性，从而减少水稻对Cd的吸收，同时促进水稻生长，提高水稻产量。它是一种具有潜在应用前景的Cd污染土壤修复材料。研究结果可为Cd污染酸性紫色土的农田修复和农业安全生产提供科学依据。
