Abstract Struvite crystallization was one of the most promising techniques for nutrient recovery from nutrient-rich wastewater. However, As(V) derived from the wastewater has been proved to adversely affect struvite crystallization. Constant composition technique was employed to quantify the effect of As(V) on struvite crystallization in the presence of As(V) under various operational conditions such as supersaturation, pH and ionic strength. Subsequently, the interaction mechanisms between As(V) and struvite crystals were further elucidated by means of XPS and FTIR. Interestingly, the roles of adsorption and coprecipitation in the interaction under various operational conditions were primarily evaluated. At a supersaturation of 0.4, pH 8.5 and 0.1 mol/L NaCl, the crystal growth rate of struvite was substantially reduced from (14.2 ± 0.3) × 10−6 to (7.6 ± 0.1) × 10−6 mol/min with As(V) concentration increasing from 0 to 10 mg/L. Nevertheless, As(V) scarcely changed the surface diffusion growth mechanism of struvite. Moreover, the adsorption and coprecipitation of As(V) accounted for its interaction with struvite. Thereinto, the adsorption mechanism was triggered by the bidentate inner-sphere surface complexes and the electrostatic interaction between As(V) and struvite. Furthermore, the influence of supersaturation and ionic strength on the inhibitory effect was found to be highly dependent of the adsorption of As(V), whereas the coprecipitation of As(V) is mainly responsible for the impact of pH. The finding herein provided a novel approach to elucidate the inhibitory mechanisms of heavy metals on struvite crystallization, which facilitated to obtain pure struvite crystals from the wastewater contaminated by heavy metals.

中文翻译：

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用于量化 As(V) 在各种操作条件下对鸟粪石结晶的影响的恒定组成技术

摘要 鸟粪石结晶是从富营养废水中回收养分最有前途的技术之一。然而，来自废水的 As(V) 已被证明会对鸟粪石结晶产生不利影响。采用恒定组成技术来量化 As(V) 在 As(V) 存在下在各种操作条件（例如过饱和度、pH 和离子强度）下对鸟粪石结晶的影响。随后，通过XPS和FTIR进一步阐明了As(V)与鸟粪石晶体之间的相互作用机制。有趣的是，主要评估了吸附和共沉淀在各种操作条件下的相互作用中的作用。在过饱和度为 0.4、pH 为 8.5 和 0.1 mol/L NaCl 时，鸟粪石的晶体生长速率从 (14.2 ± 0. 3) × 10−6 到 (7.6 ± 0.1) × 10−6 mol/min，As(V) 浓度从 0 增加到 10 mg/L。尽管如此，As(V) 几乎没有改变鸟粪石的表面扩散生长机制。此外，As(V) 的吸附和共沉淀解释了它与鸟粪石的相互作用。其中，吸附机制是由双齿内球表面复合物和As(V)与鸟粪石之间的静电相互作用触发的。此外，发现过饱和度和离子强度对抑制效果的影响高度依赖于 As(V) 的吸附，而 As(V) 的共沉淀主要负责 pH 的影响。本文的发现为阐明重金属对鸟粪石结晶的抑制机制提供了一种新方法，