给水处理厂废弃铁铝泥对正磷酸盐的吸附特征  

Characteristics of Orthophosphate Adsorption on Ferric-alum Residuals (FARs) from Drinking Water Treatment Plant

作　　者：王昌辉[1] 裴元生[1] 

机构地区：[1]北京师范大学环境学院,教育部水沙科学重点实验室,北京100875

出　　处：《环境科学》2011年第8期2371-2377,共7页Environmental Science

基　　金：国家自然科学基金项目(50979007)

摘　　要：以给水处理厂废弃铁铝泥(ferric-alum residuals,FARs)为载体,探究了FARs对正磷酸盐的吸附特征.ICP、SEM和XRD测试结果表明,FARs富含铁铝元素且为无定形结构.批量平衡实验法证实,FARs对正磷酸盐的吸附较符合伪二级动力学模型.在酸性环境条件下,磷的吸附效果最好,当pH值从4.6升至7.6时,磷的吸附量下降了40.13%,粒径为0.6～0.9 mm的FARs对磷的吸附量最大.Freundlich和Langmuir方程均能较好描述FARs对磷的等温吸附过程,相关系数分别为0.991 6和0.973 6,其磷的饱和吸附量可达45.45 mg.g-1,与文献总结的各种天然和工业材料相比,FARs具有较高的吸附量.在相同实验条件下,重复解吸实验得到磷的解吸率仅为10%左右.吸附热力学研究表明,FARs吸附磷的平衡吸附能为13.36 kJ.mol-1且ΔH0>0、ΔS0>0、ΔG0<0,吸附过程是一个自发的化学吸热反应过程.因此,利用给水处理厂废弃FARs可以高效除磷并具有"以废治废"的应用价值.Batch tests have been used to investigate the characteristics of orthophosphate adsorption on ferric-alum residuals（FARs） from drinking water treatment plant.ICP,SEM and XRD analyses confirm that the FARs enriched in Fe and Al elements and presented amorphism structure.Orthophosphate sorption by the FARs can be described by the pseudo-second-order kinetics equation.Fine adsorption effects of the FARs were found under lower pH values,particularly a 40.13% drop of the adsorptive capacity from pH 4.6 to pH 7.6.The FARs with grain sizes of 0.6-0.9 mm had the highest adsorption capacity of orthophosphate.Experimental data could be better fitted by the isotherm models of Langmuir（R2=0.973 6） and Freundlich（R2=0.991 6）.The maximal adsorptive capacity reached 45.45 mg·g-1 estimated from Langmuir isotherm model.Compared with other natural and industrial materials,FARs has relatively higher adsorption capacity.Under similar testing conditions,it was found that only about 10% orthophosphate could be desorbed from the FARs.Further study demonstrated that the mean energy of orthophosphate sorption on the FARs was 13.36 kJ·mol-1 and the ΔH00,ΔS00 and ΔG00,which indicated that orthophosphate sorption on the FARs was a spontaneously endothermic chemical reaction.It can be therefore highly valued that the FARs may be applied to phosphate removal from wastewater and surface water.

关 键 词：铁铝泥 粒径 动力学 等温线 解吸 

分 类 号：X703.1[环境科学与工程—环境工程]