Iron–arsenic coprecipitate is a kind of solid waste produced in the treatment of arsenic-bearing wastewater from non-ferrous metallurgy. Stability of amorphous coprecipitates is usually poor if the Fe/As ratio is lower. In this study, the surface of coprecipitates was deposited with aluminum hydroxide with the aim to prevent the release of arsenic. The deposition experiments were carried out at normal temperature using Al 2 (SO 4 ) 3 solutions with pH between the range of 6.0–7.0. The characterization of the coated precipitates was investigated using SEM-EDS, TEM, XRD, FTIR, and BET. The stability experiment showed that the coated precipitates exhibit a higher release of arsenic than the coprecipitates without coating. The anion exchange might have taken place in the coated surface, and the release of arsenic may be a comprehensive result.

中文翻译：

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氢氧化铝表面沉积涂层对铁砷沉淀物稳定性的影响

铁砷共沉淀物是有色冶金含砷废水处理过程中产生的一种固体废物。如果 Fe/As 比值较低，无定形共沉淀物的稳定性通常很差。在这项研究中，共沉淀物的表面沉积有氢氧化铝，目的是防止砷的释放。沉积实验在常温下使用 pH 值在 6.0-7.0 之间的 Al 2 (SO 4 ) 3 溶液进行。使用 SEM-EDS、TEM、XRD、FTIR 和 BET 研究了包覆沉淀物的表征。稳定性实验表明，有涂层的沉淀物比没有涂层的共沉淀物表现出更高的砷释放。阴离子交换可能发生在涂层表面，砷的释放可能是一个综合结果。