Journal of Hazardous Materials ( IF 12.2 ) Pub Date : 2020-05-15 , DOI: 10.1016/j.jhazmat.2020.122901 Jin Fan 1 , Xiang Chen 1 , Zibo Xu 1 , Xiaoyun Xu 1 , Ling Zhao 1 , Hao Qiu 1 , Xinde Cao 2
Waste biomass derived biochar has been proven as an effective and friendly amendment for remediation of heavy metals-contaminated soil. However, biochar is less effective for soil arsenic (As) immobilization in most cases. To improve the ability of biochar for As immobilization, in this study, the composite of biochar embedded with nano zero valent iron (nZVI/BC) was prepared through simple one-step pyrolysis of biomass sawdust and Fe2O3 mixture and then applied for amendment of two mining As-contaminated soils. Pristine sawdust biochar (BC) and nZVI alone or in combination were included for comparison. Results show that the prepared nZVI/BC contained about 40% Fe which was mainly present as Fe°. All treatments except BC reduced As concentration in (NH4)2SO4 extraction and gastrointestinal solution. Particularly, nZVI/BC reduced the labile As in (NH4)2SO4 extraction in two soils by over 93% and bioaccessible As in gastrointestinal solution decreased by over 85%. Fe° on the surface of nZVI/BC was oxidized into amorphous FeOOH which adsorbed or co-precipitated with As. Meanwhile, Ca-Fe-As-O and Al-Fe-As-O co-precipitated at the interface between nZVI/BC and two soils enriched with Ca and Al, respectively. Results indicated that the simply-prepared nZVI/BC was a promising material for remediation of As-contaminated soils.
中文翻译:
一锅合成nZVI埋藏的生物炭,用于修复两种受砷污染的采矿土壤:与铁转化相关的固定化砷。
废生物质衍生的生物炭已被证明是一种有效且友好的改良剂,可用于治理重金属污染的土壤。但是,在大多数情况下,生物炭对于固定土壤砷(As)的效果较差。为了提高生物炭固定化砷的能力,本研究通过生物质锯末和Fe 2 O 3混合物的简单一步热解制备了嵌入纳米零价铁(nZVI / BC)的生物炭复合材料,然后将其应用于修正了两种被砷污染的采矿土壤。原始木屑生物炭(BC)和单独的nZVI或组合使用的nZVI进行比较。结果表明,制备的nZVI / BC含有约40%的铁,主要以Fe°的形式存在。除BC外的所有处理均降低了(NH 4)中的As浓度2 SO 4提取和胃肠道液。特别是,nZVI / BC将两种土壤中(NH 4)2 SO 4提取中的不稳定As降低了93%以上,胃肠溶液中的生物可利用As降低了85%以上。nZVI / BC表面的Fe°被氧化成非晶态的FeOOH,然后与As吸附或共沉淀。同时,Ca-Fe-As-O和Al-Fe-As-O在nZVI / BC与两种富含Ca和Al的土壤之间的界面共沉淀。结果表明,简单制备的nZVI / BC是用于修复As污染土壤的有前途的材料。