酸改性镁剂烟气脱硫废渣除磷性能研究  

Study on phosphorus removal performance of acid modified magnesium flue gas desulfurization residue

作　　者：朱伟 董延茂 顾明玉 赵羿博 章启帆 蔡顺智[1] 

机构地区：[1]苏州科技大学环境科学与工程学院,江苏苏州215009 [2]江苏省环境功能材料重点实验室 [3]苏州科技大学化学生物与材料工程学院

出　　处：《无机盐工业》2018年第3期60-65,73,共7页Inorganic Chemicals Industry

基　　金：环境功能材料重点实验室项目(SJHG1306);2015年度研究生科研/实践创新计划项目(SKCX15_023).

摘　　要：以热电厂湿法氧化镁烟气脱硫废渣(MDR)为原料,用硫酸改性的方法制备除磷吸附剂A-MDR。通过单因素实验和正交实验确定了最佳改性条件,利用扫描电镜-能谱(SEM-EDS)、BET比表面积测定、X射线衍射(XRD)和红外光谱(IR)等方法分析了MDR和A-MDR的成分与结构,并对其除磷性能与机理进行了探究。A-MDR最佳制备条件:硫酸浓度为2.0 mol/L,固液质量比为1∶3.5,改性时间为180 min,水浴温度为65℃。MDR主要成分是硅藻土和镁盐,二氧化硅质量分数为50%~60%,氧化镁、碳酸镁等含镁化合物质量分数约为40%。A-MDR形成了以硫酸镁为主的新表面,比表面积增大了46.6%、孔容积增加了28.0%。A-MDR除磷,在溶液p H为9.0、A-MDR投加量为12 g/L、反应时间为120 min条件下,模拟废水中磷的去除率可达98.2%;且A-MDR具有抗氯离子、硫酸根和硝酸根等共存阴离子影响的能力。A-MDR对磷的吸附遵循准二级动力学方程,属于化学吸附;其等温吸附过程符合Langmuir模型,对磷的最大吸附量为27.55 mg/g。Phosphorus removal adsorbent(A-MDR) was prepared by the modification of magnesium flue gas desulfurization residue(MDR) from thermal power plant with dilute sulfuric acid.The single factor experiment and orthogonal experiment were used to fund the optimum preparation conditions of A-MDR.The composition and structure of MDR and A-MDR were analyzed of by SEM-EDS,BET,XRD,and IR etc..The phosphorus removal performance and mechanism were also studied.The optimum conditions for preparation of A-MDR were:the concentration of sulfuric acid was 2.0 mol/L,solid-liquid mass ratio of 1 ∶3.5,modification time of 180 min,and water bath temperature of 65 ℃.The main contents of MDR were diatomite and magnesium salts,and it contained 50%~60%(mass fraction) of SiO_2 and about 40% of magnesium compounds,such as magnesium oxide and magnesium carbonate etc..A-MDR formed a new surface dominated by MgSO_4,the specific surface area increased by46.6%,and the pore volume increased by 28.0%.The phosphorus removal rate of A-MDR could reach 98.2% when p H was 9,the dosage was 12 g/L and the reaction time was 120 min.It had the ability to influence the coexistence of anions,such as Cl^-,SO_4^(2-) and NO_3^(2-).The adsorption process accorded with the pseudo-second-order equation,which belonged to chemical adsorption.The adsorption process accorded with the Langmuir model,and the maximum adsorption capacity was 27.55 mg P/g.

关 键 词：镁剂脱硫废渣 除磷吸附剂 酸改性 

分 类 号：X703[环境科学与工程—环境工程]