基于给水污泥吸附水溶液中磷的影响因素

Influencing factors on adsorption phosphorous in aqueous solution based on alum sludge

以给水污泥为吸附材料,采用正交实验与单因素实验研究了多种因素对除磷效果的影响.正交实验结果表明最佳反应条件为：pH为3,粒径1.98 mm,投加量8.0 g/L,吸附时间24 h.结合SEM/XRD和EDS等表征方法,对给水污泥的表面形貌和结构特征进行表征和分析.Langmuir、Freun dlich和D-R等温吸附方程均能较好的拟合给水污泥对磷的吸附特征.在298、308和318 K温度下,Langmuir拟合得到的理论饱和吸附量分别为3.47、3.84和4.39 mg/g.由D-R方程计算的吸附自由能E为10.77 ～ 10.83 kJ/mol,表明吸附过程为离子交换吸附.

With alum sludge as the absorbent, the effects of various factors, including particle size, adsor- bent dosage, pH and contact time on adsorption, were studied by orthogonal experiment and single factor experi- ment. With the orthogonal experiment, optimal operating conditions and parameters were ascertained： the best pH of 3, the great particle size of 1.98 mm, the optimal adsorbent dosage of 8.0 g/L and contact time of 24 h. The surface＇s morphology and structure of the alum sludge were characterized and analyzed by the SEM, XRD and EDS. Langmuir, Freundlieh and Dubinin-Radushkevich（D-R） isotherms models were used to greatly de- scribe the kinetic data, and the Freundlieh equation was the best model. When the temperature was 298 K, 308 K and 318 K, respectively, the saturated extents of adsorption of phosphorous were 3.47 mg/g, 3.84 mg/g and 4.39 mg/g separately. The adsorption free energy value （E = 10.77 - 10.83 kJ/mol） calculated by the D-R e- quation indicated that the adsorption was controlled by the ion exchange adsorption.