羟基铁对污水厂二级处理出水中低浓度磷的深度处理性能

Advanced Phosphorus Removal from Low Phosphorus Concentration Water by Iron Hydroxyl

以自行开发的羟基铁作为除磷吸附剂,针对低磷浓度水研究了羟基铁吸附法深度除磷的影响因素及吸附动力学,并对污水厂二级出水进行吸附除磷试验。结果表明:当水中磷酸盐的初始浓度为0.5 mg/L、羟基铁投加量为0.03 g/L、反应体系pH值为6.0、反应时间为30 min、体系温度为25℃时,羟基铁对磷酸盐的去除率为98.3%,剩余磷酸盐浓度为0.008 mg/L;在15～35℃的吸附等温线均能用Langmuir等温吸附模型描述,模型的R^2均达到0.99以上;伪二级动力学方程能够更好地拟合羟基铁对磷的吸附过程,R^2均达到0.999以上;2 mol/L的NaOH溶液对载磷羟基铁进行解吸,解吸率为97.3%,连续再生3次后的吸附量为初始吸附量的88.1%,再生效果明显;二级出水经羟基铁吸附深度除磷后,出水TP降至0.02 mg/L,可有效控制受纳水体的富营养化。

Synthetic iron hydroxyl was used as adsorbent for advanced phosphorus removal.Influence factors and adsorption kinetics with low phosphorus concentration water were investigation.The phosphorus removal rate reached 98.3% and the residual phosphorus concentration was 0.008 mg/L under the condition of initial concentration of 0.5 mg/L,dosing quantity of 0.03 g/L,initial pH value of 6.0,adsorption time of 30 min and system temperature of 25 ℃.The adsorption isotherms under different temperature could be described by Langmuir isothermal adsorption model with correlation coefficient reaching above 0.99.The process of phosphorus adsorption could be fitted better by the pseudo-second-order model with correlation coefficient reaching above 0.999.The phosphate desorption rate from used iron hydroxyl reached 97.3% with 2 mol/L NaOH,and the adsorption capacity was 88.1% of initial capacity after three times of regeneration.After adsorption by iron hydroxyl,the concentration of TP from the second effluent could be decreased to 0.02 mg/L,reducing the eutrophication of receiving water effectively.