金属氧化物改性生物炭对镉污染土壤菠菜生长和镉积累的影响

Effects of metal oxide modified biochar on spinach growth and cadmium accumulation in Cd-contaminated soil

对重金属具有良好吸附能力的金属氧化物改性生物炭材料是近年来热门的土壤修复材料,然而关于不同金属氧化物改性生物炭对土壤中Cd钝化的研究较少。本研究采用Cd污染农田土壤开展菠菜盆栽试验,研究了铁氧体改性生物炭、磁铁矿改性生物炭和水滑石改性生物炭对菠菜生长和Cd积累的影响。结果表明:在施用量均为5 g·kg^(-1)的条件下,金属氧化物改性生物炭处理可显著提高土壤pH和有机质含量。与对照相比,铁氧体改性生物炭、磁铁矿改性生物炭和水滑石改性生物炭使土壤DTPA-Cd含量分别降低了23.4%、24.8%和37.1%,生物富集系数降低了4.00%、13.3%和65.0%。此外,水滑石改性生物炭使植株干质量增加4.27倍,显著降低了Cd积累量(59.5%)。金属氧化物改性生物炭能提高土壤pH,增加土壤有机质含量,降低土壤Cd的有效性和移动性,提高土壤质量,进而促进菠菜的生长和抑制菠菜对Cd的积累。研究表明,水滑石改性生物炭在促进菠菜生长和钝化土壤Cd方面具有较大优势。

Metal oxide-modified biochar materials with good adsorption capacity for heavy metals have become popular soil remediation materials in recent years.However,there are few studies on the immobilization of Cd in soil using different metal oxide-modified biochars.In this study,the effects of ferrite-modified,magnetite-modified,and hydrotalcite-modified biochars on the growth and Cd accumulation in spinach were studied.The results demonstrated that under the application rate condition of 5 g·kg^(-1),metal oxide-modified biochar treatment could significantly improve soil pH and organic matter content.Compared with the control,treatment with ferrite-modified,magnetite-modified,and hydrotalcite-modified biochars reduced the DTPA-Cd content by 23.4%,24.8%,and 37.1%,and the enrichment coefficients by 4.00%,13.3%,and 65.0%,respectively.In addition,hydrotalcite-modified biochar increased the plant dry weight by 4.27 times and significantly reduced Cd accumulation(59.5%).In conclusion,a metal oxide-modified biochar can increase soil pH and soil organic matter content,reduce the availability and mobility of soil Cd,and improve soil quality,thereby promoting the growth of spinach and inhibiting the accumulation of Cd in spinach.Hydrotalcite-modified biochar performs significant advantages in promoting the growth of spinach and inactivating the soil Cd.