The biogenic mackinawite (FeS) is a promising remover for hexavalent chromium. However, FeS is susceptible to aggregation, affecting the removal efficiency of Cr(VI). To address the aggregation of FeS, kaolinite was selected as the stabilizer to disperse biogenic FeS. Results showed that kaolinite could be used as a supporting material for biogenic FeS during the formation process, which efficiently decreased the aggregation of FeS. FeS-kaolinite enabled to increase the rate and capability of Cr(VI) removal, and the maximum removal capability of FeS-kaolinite reached 399 mg/g at pH 7, which was 2.4 times higher than that of FeS only. The optimal concentration of kaolinite was 3 g/L where the percentage of FeS on FeS-kaolinite was 5% (wt). The removal kinetic was well fitted with the pseudo-second-order model and Cr(VI) could be removed quickly and efficiently in the pH range of 3-8. The efficiency of Cr(VI) removal was not dependent on ionic strength (Cl-, 0.1-1000 mM), HA (5-20 mg/L) and co-existing cations (Ca2+, Zn2+,Cu2+, and Cd2+, 30 mM). Cr(VI) could be rapidly reduced to Cr(III) by FeS-kaolinite on the surface and Cr(III) was coprecipitated into Cr(OH)3 and CrxFe1-x(OH)3. This study suggests biogenic FeS-kaolinite is a good candidate for remediation of Cr(VI) contaminated environment.

中文翻译：

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使用生物麦金石（FeS）沉积的高岭石去除六价铬。

生物型麦基钠铁矿（FeS）是一种有前途的六价铬去除剂。但是，FeS易于聚集，影响Cr（VI）的去除效率。为了解决FeS的聚集，选择高岭石作为稳定剂以分散生物型FeS。结果表明，高岭石在形成过程中可用作生源性FeS的载体材料，有效降低了FeS的聚集。FeS-高岭石能够提高Cr（VI）的去除速率和能力，并且在pH 7时，FeS-高岭石的最大去除能力达到399 mg / g，这仅比FeS高2.4倍。高岭石的最佳浓度为3 g / L，其中FeS在FeS高岭石上的百分比为5％（wt）。去除动力学很好地拟合了拟二阶模型，并且可以在3-8的pH范围内快速有效地去除Cr（VI）。Cr（VI）去除的效率不取决于离子强度（Cl-，0.1-1000 mM），HA（5-20​​ mg / L）和共存阳离子（Ca2 +，Zn2 +，Cu2 +和Cd2 +，30 mM） ）。Cr（VI）可以通过表面的FeS-高岭石快速还原为Cr（III），并且Cr（III）共沉淀为Cr（OH）3和CrxFe1-x（OH）3。这项研究表明，生物型FeS-高岭石是修复Cr（VI）污染环境的理想人选。Cr（VI）可以通过表面的FeS-高岭石快速还原为Cr（III），并且Cr（III）共沉淀为Cr（OH）3和CrxFe1-x（OH）3。这项研究表明，生物型FeS-高岭石是修复Cr（VI）污染环境的理想人选。Cr（VI）可以通过表面的FeS-高岭石快速还原为Cr（III），并且Cr（III）共沉淀为Cr（OH）3和CrxFe1-x（OH）3。这项研究表明，生物型FeS-高岭石是修复Cr（VI）污染环境的理想人选。