A.ferrooxidans对高硫煤矸石去除酸性水体中Cr(VI)的强化作用

本研究考察了Acidithiobacillus ferrooxidans（A.ferrooxidans）联合高硫煤矸石（富含FeS₂）对模拟煤矿酸性水体中Cr（VI）的去除效果.结果表明，处理Cr（VI）初始浓度为50mg/L的模拟煤矿酸性废水（pH=2.5）时，投配率为6.67~33.33g/L高硫煤矸石可使Cr（VI）去除达到良好效果.50mg/LCr（VI）在24h内即可完全被高硫煤矸石中的FeS₂还原成Cr（III），且在反应终点时（120h），6.67，13.33，33.33g/L高硫煤矸石对还原产物Cr（III）的吸附去除率分别为7.1%、20.2%、29.1%.然而，在高硫煤矸石的还原和吸附作用下，大部分的Cr仍以Cr（III）形式残留在酸性水体中，且高硫煤矸石的大量投加也给水体带来了Fe²⁺、Fe³⁺、SO₄^2-等二次污染物.在高硫煤矸石-Cr（VI）体系中引入A.ferrooxidans和9K培养基后，A.ferrooxidans介导的Fe²⁺生物氧化及产物Fe³⁺水解矿化过程可促进部分Fe²⁺、Fe³⁺、SO₄^2-等向次生铁矿物（包括施氏矿物和黄钾铁矾）转变，从而使模拟酸性水体中残留的Cr（III）通过次生铁矿物的吸附或共沉淀作用被清除.在A.ferrooxidans强化作用下，模拟煤矿酸性废水中Cr（VI）在96h即可达到99.4%的去除率.

The enhancement of Acidithiobacillus ferrooxidans on the removal of Cr(VI) from acid coal mine drainage by high-sulfur coal gangue

The removal efficiency of Cr(VI) in simulated acid coal mine drainage (ACMD) was investigated through Acidithiobacillus ferrooxidans combined with high-sulfur coal gangue (rich in FeS₂). Results showed that in stimulated ACMD (pH=2.5) with 50mg/L Cr(VI), and 6.67~33.33g/L of high-sulfur coal gangue could achieve the ideal effect on Cr(VI) removal. 50mg/L of Cr (VI) could be completely reduced to Cr (III) by FeS₂ at 24h. 7.1%, 20.2% and 29.1% of Cr(III) was removed via absorption by 6.67, 13.33, and 33.33g/L high-sulfur coal gangue at 120h, respectively. However, after the reduction and adsorption of high-sulfur coal gangue, most of Cr remains in simulated ACMD as Cr(III), and large amount of high-sulfur coal gangue also led to secondary pollutants (Fe²⁺, Fe³⁺ or SO₄^2-). After the introduction of A.ferrooxidans and 9K medium into high-sulfur coal gangue and Cr(VI) system, A.ferrooxidans mediated Fe²⁺ biooxidation and Fe³⁺ hydrolytic mineralization promoted the conversion of Fe²⁺, Fe³⁺ or SO₄^2- to secondary iron minerals (including schwertmannite and jarosite), so that residual Cr(III) was removed by adsorption or co-precipitation. Under the enhancement of A.ferrooxidans, the removal efficiency of Cr(VI) in simulated ACMD could reached as high as 99.4% in 96h.