不同有机质组分对结晶法回收磷的影响

Effect of Different Organic Matters on Phosphorus Recovery by Crystallization

摘要: 蓝铁矿结晶法是一种极具前景的污水污泥磷回收技术，但有机物会干扰蓝铁矿的结晶过程。本研究选取了葡萄糖、牛血清白蛋白(BSA)、腐殖酸(HA)和海藻酸钠(SA)作为特征有机物，探究了有机物类型对蓝铁矿结晶法磷回收效率及产物特性的影响。结果表明，葡萄糖对磷回收影响较小，HA和SA对磷回收具有抑制作用。除葡萄糖外，其他三种有机物均改变了蓝铁矿结晶产物的微观形貌。机理研究表明，Fe²⁺易与有机物发生络合作用，从而降低了磷回收的效率；而HA和SA在晶体表面的吸附抑制了蓝铁矿晶体的生长。此外，BSA和SA通过富集Fe²⁺提供成核位点促使结晶产物由单层结构转变为堆叠结构。本研究结果阐明了有机物干扰蓝铁矿结晶的机制，为蓝铁矿结晶法磷回收工艺提供了新见解。

Abstract: Vivianite crystallization is a promising technology for recovering phosphorus (P) from wastewater and sludge. However, organic substances can significantly interfere with this process. This study investigated the effects of four characteristic organic compounds—glucose, bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA)—on phosphorus recovery efficiency and product characteristics. Results indicated that while glucose had a negligible impact on recovery, HA and SA exerted inhibitory effects. Furthermore, with the exception of glucose, all tested organic substances altered the microscopic morphology of the vivianite crystals. Mechanistic analysis revealed that Fe²⁺ tends to form coordination bonds with these organic substances, thereby reducing phosphorus recovery efficiency. Specifically, the adsorption of HA and SA onto crystal surfaces impeded crystal growth. Conversely, BSA and SA promoted the transformation of the crystallization products from a single-layer to a stacked structure by providing nucleation sites through Fe²⁺ enrichment. These findings elucidate the mechanisms by which organic substances interfere with vivianite crystallization, offering new insights for optimizing phosphorus recovery processes.