钢铁废水污泥吸附除磷特性

Phosphorus adsorption characteristics by steel wastewater sludge

为处理含磷废水同时实现钢铁污泥资源化利用,将钢铁污泥用于吸附除磷,从磷吸附影响因素、动力学模型、吸附等温线等方面研究了钢铁污泥对水中磷酸盐的吸附特性,并通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)等表征手段对吸附机理进行了探究.结果显示,钢铁污泥对水中磷具有优良的吸附性能,在pH=2.00,温度为40℃时,磷的理论饱和吸附量可达8.917mg/g.实验数据符合Langmuir方程,为单分子层吸附.60min即可达吸附平衡,吸附过程符合拟二阶动力学方程,主要为化学吸附.SEM和XRD分析结果表明,吸附后污泥表面可能存在FePO4、CaxFey(PO4)2x/3+y等物质,推测磷的去除可能是PO4^3-与Fe^3+或Ca^2+等的化学沉淀作用,以及Fe^3+的水解产物与PO43-发生化学吸附并进行络合反应形成络合物的共同沉淀作用.研究结果表明钢铁污泥在吸附除磷方面具有潜在应用价值.

In order to realize resource utilization of steel sludge and phosphorus removal in wastewater,steel wastewater sludge was used as an adsorbent for the phosphorus removal from wastewater.It studied the adsorption characteristics of phosphate by steel sludge,including influence factors,dynamic model,adsorption isotherm,and the mechanism of adsorption by scanning electron microscope(SEM)and X-ray diffractometer(XRD).The results showed that steel sludge had a good adsorption capacity for phosphate in wastewater.When temperature was 40℃ and pH was 2.00,the theoretical saturated adsorption capacity of phosphorus was 8.917mg/g.The data were well described by Langmuir model,indicating that it was a multilayer adsorption process.It took 60min to achieve adsorption equilibrium.It met the Pseudo second-order equation,demonstrating that the process was chemical adsorption.SEM and XRD analysis showed that there might be something like FePO4,CaxFey(PO4)2x/3+y on the surface of the steel sludge after adsorption,and it was speculated that the phosphorus was removed by precipitation with Fe^3+ or Ca^2+,and chemical adsorption of hydrolysates of Fe^3+ and PO4^3- and then co-precipitation of complex compound through complexation reaction.Overall,steel sludge was a potential adsorbent for the removal of phosphorus in wastewater.