The modified hydrochar was prepared by a facile one-pot lime-assisted hydrothermal synthesis approach and the modified hydrochar and pristine hydrochar were investigated to immobilize the heavy metals (HMs) of Pb and Cd in contaminated soils. The results showed that the modified hydrochar exerted significantly enhanced effectiveness in immobilizing Pb and Cd comparing to pristine hydrochar, resulting from the increased surface functionality and non-crystalline properties, increased pH value and enhanced electronegativity of hydrochar. By introduction with 5% modified hydrochar, the contaminated soils showed the highest value of 34.5% (Pb) and 8.1% (Cd) reductions in leaching toxicity, and significant improvements of 95.1% (Pb) and 64.4% (Cd) were observed. In addition, the concentrations of acid soluble fraction were remarkably reduced by 54.0% (Pb) and 27.0% (Cd), and the reductions were much higher than that of 29.5% (Pb) and 8.3% (Cd) for 5% pristine hydrochar treatment. The enhanced surface complexation, precipitation and cation-π interaction played an important role in the immobilization of HMs in soils. The present study offered a novel and cost-effective approach to prepare soil amendment from waste biomass towards HMs immobilization in contaminated soils.

中文翻译：

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改性水炭将重金属固定在污染土壤中的效率、风险评估和潜在机制


采用简便的一锅石灰辅助水热合成法制备改性水炭，研究改性水炭和原始水炭在污染土壤中固定 Pb 和 Cd 的重金属 （HMs）。结果表明，与原始水炭相比，改性水炭在固定 Pb 和 Cd 方面的有效性显著提高，这是由于水炭的表面功能和非结晶性能增加、pH 值增加和电负性增强。通过引入 5% 改性水炭，污染土壤的浸出毒性降低最高，分别为 34.5% （Pb） 和 8.1% （Cd），并观察到 95.1% （Pb） 和 64.4% （Cd） 的显著改善。此外，酸溶性馏分浓度显著降低了 54.0% （Pb） 和 27.0% （Cd），降幅远高于 5% 纯水炭处理的 29.5% （Pb） 和 8.3% （Cd）。增强的表面络合、沉淀和阳离子-π相互作用在 HMs 在土壤中的固定化中起了重要作用。本研究提供了一种新颖且具有成本效益的方法来制备来自废弃生物质的土壤改良剂，以用于在受污染土壤中固定 HMs。