Mahdy Ahmed M, Zhang Tiequan, Lin Zhi-Qing, Fathi Nieven O, Badr Eldin Rasha M
Department of Soil and Water Sciences, Faculty of Agriculture, Alexandria University, Alexandria 21568, Egypt.
Harrow Research and Development Centre, Agriculture and Agri-Food Canada, Harrow, ON N0R 1G0, Canada.
Materials (Basel). 2021 May 19;14(10):2655. doi: 10.3390/ma14102655.
Nickel (Ni) accumulation in wastewater treatment sludge poses a potential environmental risk with biosolids-land application. An incubation experiment was conducted to evaluate the effect of nanoparticles of zero-valent iron (nZVI) on Ni sorption in biosolids-treated agricultural soils. Two application rates of biosolids (0, 5%, /) and four treatment levels (0, 1, 5, and 10 g/kg) of nZVI were examined, either separately or interactively. The results of this study showed significant differences in Ni sorption capacity between different nZVI treatments. The initial Ni concentration in biosolids-amended soil significantly affected Ni sorption in the soil treated with nZVI. The "H-shape" of sorption isotherm in nZVI-treated soil reflects strong interaction between the Ni concentration and the nZVI treatment, while the C-shape of sorption isotherm in biosolids-amended soil without the nZVI treatment indicates intermediate affinity for Ni sorption. Nickel retention in soil was increased with the increase of nZVI levels. The removal efficiency of Ni by nZVI from solution was increased with the increase of pH from 5 to 11 and reached a maximum of 99.56% at pH 11 and nZVI treatment of 10 g/kg. The Ni desorption rate decreased from 92 to 7, 4, and 1% with increasing nZVI treatment levels from 0 to 1, 5, and 10 g/kg, respectively, with a soil Ni concentration of 50 mg/L. The maximum adsorption capacity (?) of 10 g/kg nZVI-treated soil was 333.3 mg/g, which was much higher than those from the other treatments of 0 (5 mg/g), 1 (25 mg/g), and 5 g/kg (125 mg/g). The underlying mechanism for Ni immobilization using nZVI in an aquatic environment is controlled by a sorption process, reduction of metal ion to zero-valent metal, as well as (co)precipitation. Moreover, increasing the nZVI treatment level in biosolids-amended soil significantly decreased bioavailable Ni concentrations in the soil.
废水处理污泥中的镍（Ni）积累会因生物固体土地施用而带来潜在的环境风险。进行了一项培养实验，以评估零价铁纳米颗粒（nZVI）对生物固体处理过的农业土壤中镍吸附的影响。研究了两种生物固体施用量（0、5%，/）和四个nZVI处理水平（0、1、5和10 g/kg），单独或交互研究。本研究结果表明，不同nZVI处理之间的镍吸附能力存在显著差异。生物固体改良土壤中的初始镍浓度显著影响nZVI处理土壤中的镍吸附。nZVI处理土壤中吸附等温线的“H形”反映了镍浓度与nZVI处理之间的强烈相互作用，而未进行nZVI处理的生物固体改良土壤中吸附等温线的“C形”表明对镍吸附具有中等亲和力。土壤中镍的保留量随nZVI水平的增加而增加。随着pH值从5增加到11，nZVI对溶液中镍的去除效率增加，在pH值为11且nZVI处理量为10 g/kg时达到最大值99.56%。在土壤镍浓度为50 mg/L时，随着nZVI处理水平从0增加到1、5和10 g/kg，镍的解吸率分别从92%降至7%、4%和1%。10 g/kg nZVI处理土壤的最大吸附容量（?）为333.3 mg/g，远高于其他处理（0（5 mg/g）、1（25 mg/g）和5 g/kg（125 mg/g））。在水生环境中使用nZVI固定镍的潜在机制受吸附过程、金属离子还原为零价金属以及（共）沉淀控制。此外，增加生物固体改良土壤中的nZVI处理水平显著降低了土壤中生物可利用的镍浓度。
