ABSTRACT

The combined remediation of cadmium (Cd) and arsenic (As) in paddy soils faces many challenges due to their opposite behavior. A pot study was conducted to evaluate the impact of biochar (BC), goethite (G), and goethite modified biochar (GBC) at a 1% application rate on the Chinese cabbage growth, uptake and immobilization of Cd and As in co-contaminated paddy soil. GBC composites were prepared at two different initial mass ratios (1:1 and 2:1) of iron/biochar (Fe/BC). Goethite modified biochar composite at Fe/BC initial mass ratios of 1:1 and 2:1 were labeled as GBC1 and GBC2, respectively. The results showed that GBC amendments significantly improved Chinese cabbage growth, chlorophyll content, and gas exchange attributes compared to BC and G applied singly. Biochar decreased Cd uptake by Chinese cabbage shoots and roots while increased As uptake by shoots and roots. The GBC1 amendment reduced Cd and As uptake by Chinese cabbage shoots (47.27% and 35.20%) and roots (36.80% and 41.12%), respectively, and reduced Cd and As bioaccessibility by 40.09% and 39.35%, respectively, compared to unamended soil. GBC is generally simple to synthesize from crop residue and is an environmentally acceptable material when used for Cd and As remediation in co-contaminated paddy soil.

摘要

水稻土中镉 (Cd) 和砷 (As) 的联合修复因其相反的行为而面临许多挑战。进行了一项盆栽研究，以评估生物炭 (BC)、针铁矿 (G) 和针铁矿改性生物炭 (GBC) 在 1% 施用率下对大白菜生长、Cd 和 As 在共同污染环境中的吸收和固定的影响水稻土。GBC 复合材料以铁/生物炭 (Fe/BC) 的两种不同初始质量比（1:1 和 2:1）制备。Fe/BC 初始质量比为 1:1 和 2:1 的针铁矿改性生物炭复合材料分别标记为 GBC1 和 GBC2。结果表明，与单独施用 BC 和 G 相比，GBC 改良剂显着改善了大白菜的生长、叶绿素含量和气体交换特性。生物炭降低了大白菜新梢和根对Cd的吸收，同时增加了新梢和根对As的吸收。与未改良的土壤相比，GBC1 改良剂分别降低了大白菜芽（47.27% 和 35.20%）和根系（36.80% 和 41.12%）对 Cd 和 As 的吸收，并且分别将 Cd 和 As 的生物可吸收性降低了 40.09% 和 39.35% . GBC 通常很容易从作物残渣中合成，并且在用于共同污染的稻田土壤中的 Cd 和 As 修复时是一种环境可接受的材料。