Nguyen Thị Bich Hanh, Van Huu-Tap, Dang Van Minh, Ha Tran Thi Ngoc, Nguyen Thi Tuyet, Hoang Trung Kien
Faculty of Natural Resources and Environment, TNU - University of Sciences, Tan Thinh ward, Thai Nguyen City, 25000, Viet Nam.
Faculty of Environment, TNU - University Agriculture and Forestry (TUAF), Quyet thang Ward, Thai Nguyen City, 25000, Viet Nam.
Heliyon. 2024 May 14;10(10):e31084. doi: 10.1016/j.heliyon.2024.e31084. eCollection 2024 May 30.
The study investigated the effectiveness of Mg/Al LDH-zeolite (MALZ) in immobilizing exchangeable Cr (e-Cr) within the soil. The research systematically evaluated various variables affecting the immobilization of e-Cr in contaminated soil (CS), including soil pH levels (ranging from 5.0 to 9.0), different weight ratios of MALZ (1 %, 3 %, and 5 %), durations of differing incubation periods (15, 30 and 45 days), and different SM content levels (30 %, 50 %, and 70 %). The initial concentration of Cr in the CS was maintained at 50 mg/kg. The investigation findings revealed that the optimal conditions for immobilizing the e-Cr were a soil pH of 5.0, an MALZ weight ratio of 3 %, an incubation period of 30 days, and an SM level of 70 %. Under these ideal conditions, the percentage of e-Cr within the CS decreased significantly, from 87.49 % (45.64 mg/kg) in the control treatment (CT) to just 19.82 % (10.08 mg/kg) when incubated with MALZ. The primary mechanisms responsible for immobilizing the e-Cr onto MALZ included pore filling, reduction processes, co-precipitation, organic interactions and electrostatic attractions leading to the formation of carbonate-bound complexes such as Cr(VI)-carbonate, Cr(III)-carbonate, and organic complexes. Surface functional groups on MALZ, housing iron and aluminium oxyhydroxides and silicon and oxygen elements, expedited these procedures. This study provided a valuable understanding of the mitigation of soils contaminated with chromium and contributed to understanding the relations between MALZ and the e-Cr in the soil. The discoveries carry substantial consequences for the advancement of efficient remediation technologies.
该研究调查了镁铝层状双氢氧化物-沸石（MALZ）在固定土壤中可交换态铬（e-Cr）方面的有效性。该研究系统评估了影响污染土壤（CS）中e-Cr固定化的各种变量，包括土壤pH值水平（范围为5.0至9.0）、MALZ的不同重量比（1%、3%和5%）、不同培养期的持续时间（15、30和45天）以及不同的土壤有机质（SM）含量水平（30%、50%和70%）。CS中Cr的初始浓度保持在50mg/kg。调查结果表明，固定e-Cr的最佳条件是土壤pH值为5.0、MALZ重量比为3%、培养期为30天以及SM水平为70%。在这些理想条件下，CS中e-Cr的百分比显著下降，从对照处理（CT）中的87.49%（45.64mg/kg）降至与MALZ一起培养时的仅19.82%（10.08mg/kg）。将e-Cr固定在MALZ上的主要机制包括孔隙填充、还原过程、共沉淀、有机相互作用和静电吸引，导致形成碳酸盐结合的络合物，如Cr(VI)-碳酸盐、Cr(III)-碳酸盐和有机络合物。MALZ上的表面官能团含有铁和铝的羟基氧化物以及硅和氧元素，加速了这些过程。这项研究为减轻铬污染土壤提供了有价值的认识，并有助于理解MALZ与土壤中e-Cr之间的关系。这些发现对高效修复技术的发展具有重大意义。
