Removal of arsenic from aqueous solution in the form of scorodite is one of the promising processes for the disposal of arsenic-containing wastewater. While it suffers from the strict reaction conditions including high Fe/As molar ratio, narrow pH range, and low Fe/As supersaturation when the liquid iron sources of Fe²⁺/Fe³⁺ are used as the iron sources. We proposed to use limonite as an in situ solid iron source to promote scorodite crystallization via heterogeneous nucleation for the effective removal of arsenic from high-arsenic smelting wastewater. Under the condition of 90 °C, limonite dosage at an Fe/As molar ratio of 4 and pH of 1.5, 99.6% of arsenic in the smelting wastewater (As 10300 mg/L and sulphuric acid 72500 mg/L) was precipitated in the form of well-crystallized and environmentally stable scorodite with a particle size around 4.6 μm. Limonite acts as an in situ iron donator and seeds, allowing a low iron supersaturation in the solution during the arsenic precipitation and transformation into scorodite. Moreover, the residual arsenic concentration in the filtrate obtained from the abovementioned scorodite synthesis could be further lowered to 0.1 μg/L using fresh limonite in virtue of its high arsenic adsorbability. The proposed process shows a great potential for the arsenic removal from smelting wastewater, which will advance the large-scale disposal of arsenic-bearing wastewater and provide an important insight into the application of solid iron source for scorodite synthesis and arsenic fixation.

从臭葱石形式的水溶液中除去砷是用于处理含砷废水的有前途的方法之一。当使用Fe ²⁺ / Fe ³⁺的液态铁源作为铁源时，它具有严格的反应条件，包括高Fe / As摩尔比，狭窄的pH范围和低Fe / As过饱和度。我们建议使用褐铁矿作为原位固态铁源，以通过以下方式促进臭葱石结晶异相成核，可有效去除高砷冶炼废水中的砷。在90°C的条件下，Fe / As摩尔比为4且pH值为1.5的褐铁矿剂量使冶炼废水中的砷（As为10300 mg / L，硫酸为72500 mg / L）中的砷含量为99.6％。形态良好的结晶且对环境稳定的臭葱石，粒径约为4.6μm。褐铁矿作为原位铁供体和种子，在砷沉淀并转变为臭葱石期间，溶液中的铁过饱和度较低。而且，由于上述臭葱石合成所获得的滤液中砷的吸附性高，因此可以将残留砷浓度进一步降低至0.1μg/ L。