新生态水合氧化铁去除水中磷酸根的效能研究

以新生态水合氧化铁(FHIO,由高铁酸钾和氯化亚铁配制)为混凝剂,考察了对水中磷酸根的处理效能,以及有机物浓度、pH、温度、浊度等参数对其去除磷酸根的影响。通过对原水pH和浊度变化的分析,发现FHIO的水解过程不同于普通铁盐,可形成细小、比表面积大、吸附能力强的铁氧体。在投加氯化铁进行混凝时,随着投量(6、7、8mg/L)的增加,对磷酸根的去除率分别达到了54%、59%、70%。而在相同的总铁投量下,FHIO对磷酸根的去除率分别提高了11%、13%、9%。水中有机物浓度的增加,对FHIO的除磷效果有一定的影响,这是因为有机物在一定程度上抑制了Fe(Ⅱ)的氧化,间接地影响了FHIO的生成,从而降低了除磷效果。在较低温度、pH和浊度时,FHIO对磷酸根的去除效果明显优于单独铁盐的,这是由于FHIO的无定形状态和细小的颗粒度决定其受这些因素的影响较小。

Study on Efficiency of Freshly Hydrated Iron Oxide for Phosphate Removal from Water

Using freshly hydrated iron oxide (FHIO) prepared by interaction between potassium ferrate and ferrous chloride as coagulant, the treatment efficiency of phosphate from water was studied, and the influence of organic matter concentration, pH, temperature and turbidity on phosphate removal was investigated. Through analyzing changes in pH and turbidity of raw water, it is found that the hydrol-ysis process of FHIO is different from that of common iron salt, and fine particles of freshly amorphous hydrated iron oxide with large specific surface area and strong adsorption capacity are formed. When the dosage of ferric chloride is 6 mg/L, 7 mg/L and 8 mg/L, the removal rates of phosphate are 54%, 59% and 70% respectively, while using the same amount of total iron, the removal rates of phosphate by FHIO are increased by 11%, 13% and 9% respectively. The increase of organic matters affects the removal of phosphate by FHIO, which suggests that organic matters inhibit the oxidation of Fe(Ⅱ), as well as the formation of FHIO, so the removal efficiency of phosphorus is reduced. Under the condition of low tem-perature, pH and turbidity, the removal efficiency of phosphate by FHIO is significantly higher than that by iron salt alone. FHIO is little affected by these factors due to its amorphous state and small particle size.