负载铁生物炭对雄黄矿尾渣砷的钝化效果

发布时间：2018-08-03 16:59

【摘要】：湖南石门雄黄矿矿区内大量As含量极高的尾渣,严重威胁着当地环境安全与居民生命健康.为推动实现对雄黄矿高As尾渣的稳定化处理,系统分析了Fe BC(负载铁生物炭)对雄黄矿尾渣中As的钝化效果,并对Fe BC钝化As的发生机制进行探讨.结果表明:水平振荡试验和合成沉降浸出试验(synthetic precipitation leaching procedure,SPLP)中尾渣As的浸出浓度分别为103.7和173.5 mg/L;Fe BC的加入〔矿渣与Fe BC的比例(w/w)为4∶1〕使尾渣中As的浸出浓度降低72.2%~79.2%.在以模拟酸雨为淋溶液的柱试验中,Fe BC处理使淋出液中ρ(As)下降79.1%~99.3%,As淋失总量减少92.8%,但酸雨淋溶量的持续增加使出水中ρ(As)随p H的降低而缓慢上升.FTIR(傅里叶红外光谱)分析发现,Fe BC表面负载的Fe原子通过羟基与砷酸根之间的配位基交换作用吸附As是Fe BC高效钝化尾渣中As的关键机制;同时,生物炭载体表面含氧官能团还可能通过氢键与As氧合阴离子或分子发生了吸附反应.研究显示,Fe BC在钝化雄黄矿尾渣中高含量As方面具有突出优势,可用于快速降低矿渣中As的浸出毒性;但在长期酸雨淋溶条件下,可能需要设置酸度缓冲层以充分保障Fe BC钝化As作用的稳定性和持久性.
[Abstract]:A large amount of as residue in the realgar mine area of Shimen Hunan Province is a serious threat to the safety of local environment and the life and health of residents. In order to realize stabilization treatment of high as tail slag of realgar ore, the passivation effect of Fe BC (loaded iron biochar on as in realgar tailings was analyzed systematically, and the mechanism of as passivation in realgar ore tailings was discussed. The results showed that the leaching concentration of as in the tailings was 103.7 and 173.5 mg / L respectively (the ratio of slag to FeBC was 4:1) in the horizontal oscillation test and the synthetic sedimentation leaching test. The leaching concentration of as in the tailings was reduced by 72.2% and 79.2% respectively (the ratio of slag to FeBC was 4:1). In the column experiment using simulated acid rain as leaching solution, the total leaching amount of 蟻 (As) in leaching solution decreased 79.1% and 99.3%, but the continuous increase of leaching amount of acid rain caused 蟻 (As) to rise slowly with the decrease of pH. FTIR (Fourier Infrared Spectroscopy) It is found that the adsorption of as by Fe atoms supported on the surface of Fe BC through the exchange of hydroxyl groups with arsenate is the key mechanism for the passivation of as in the tailings of Fe BC. At the same time, the oxygen functional groups on the surface of the biological carbon carrier may also react with as oxygen anion or molecule by hydrogen bond. The results show that the high content of as in the realgar tailings of passivating realgar has a prominent advantage and can be used to reduce the leaching toxicity of as in the slag rapidly, but under the condition of acid rain leaching for a long time, Acidity buffer layer may be needed to ensure the stability and durability of as passivated by Fe BC.
【作者单位】：湖南师范大学资源与环境科学学院;南开大学环境科学与工程学院;
【基金】：国家自然科学基金项目(41301339) 湖南省地理学重点学科项目霍英东教育基金会高等院校青年教师基金项目(151029)
【分类号】：X754

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