锰铝双氧化物改性生物炭减缓土壤重金属对黑麦草的毒性作用

电子垃圾拆解过程中引起的土壤重金属铜(Cu)和镉(Cd)复合污染现象成为一个严峻的问题,为了解决这一问题,利用废弃的螃蟹壳生物质与锰铝盐进行共沉淀后共热解制备了螃蟹壳生物炭(BC)和片状锰铝双氧化物改性的螃蟹壳生物炭(LDO/BC)材料.污染土壤经过BC和LDO/BC修复后,土壤pH、有效磷、速效钾和酶活性得到了提升,土壤中的DTPA-Cu和DTPA-Cd含量显著降低.微生物群落分析表明BC-1%能促进Gemmatimonadota(芽单胞菌)和Acidobacteriota(酸杆菌)相对丰度的上升,而LDO/BC-1%能促进Proteobacteria(变形菌)相对丰度的上升,且变形菌有利于减少Cd在植物中的积累作用.在修复后的土壤中种植黑麦草培养28 d,结果表明,经过投加量为5%BC和1%LDO/BC分别修复后土壤种植的黑麦草发芽率分别提高29%和60%,生长状况更佳,并且黑麦草植株内Cu和Cd的含量相对于未经生物炭材料处理的空白组显著降低.LDO/BC-1%处理组相对于其他处理组表现出更优异的修复效果,且负载在LDO/BC上的Mn可以有效地降低黑麦草吸收土壤中的重金属Cd.

Mn/Al-layered Double Oxide-loaded Biochar Reduced the Toxic Effects of Heavy Metals on Ryegrass in Soil

The combined pollution of heavy metal Cu and Cd in soil induced by the e-waste dismantling process has become a severe problem. To deal with this issue, crab shell biochar (BC) and Mn/Al-layered double oxide-loaded crab shell biochar (LDO/BC) were prepared using coprecipitation and co-pyrolysis of discarded crab shells and manganese aluminum salt. The experimental results showed that not only were the soil pH, available phosphorus, available potassium, and soil enzymatic activity enhanced, but the contents of DTPA-Cu and DTPA-Cd in the soil were also reduced after remediation by BC and LDO/BC. Microbial community analysis indicated that BC-1% could promote the relative abundance of Gemmatimonadota and Acidobacteriota; meanwhile, LDO/BC-1% could promote the relative abundance of Proteobacteria, which could reduce the accumulation of Cd in plants. Ryegrass was planted for further investigating the toxic effect of heavy metals in soil after remediation. The results demonstrated that after remediating with BC-5% and LDO/BC-1%, ryegrass grew more vigorously and with a lower content of the heavy metals Cu and Cd in the plants than that of CK, and the germination rate increased by 29% and 60%, respectively. Further, LDO/BC-1% had a more excellent remediation performance than that of the other groups, and the Mn in LDO/BC could reduce the content of heavy metal Cd adsorbed by ryegrass in soil.