酸改性镁剂烟气脱硫废渣除磷性能研究
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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.
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.
引文
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[20]李佳,林建伟,詹艳慧,等.镧改性沸石对水中磷酸盐和铵的去除性能[J].上海海洋大学学报,2012,21(5):800-808.
[21]Cui H J,Wang M K,Fu M L,et al.Enhancing phosphorus availability in phosphorus-fertilized zones by reducing phosphate adsorbed on ferrihydrite using rice straw-derived biochar[J].Journal of Soils and Sediments,2011,11:1135-1141.
[22]Yu J,Liang W,Wang L,et al.Phosphate removal from domestic wastewater using thermally modified steel slag[J].Journal of Environmental Sciences,2015,31:81-88.
[23]李坤权,郑正,罗兴章,等.KOH活化微孔活性炭对对硝基苯胺的吸附动力学[J].中国环境科学,2010,30(2):174-179.
[24]陆燕勤,朱丽,何昭菊,等.沸石负载氧化铁吸附剂吸附除磷研究[J].环境工程,2015(4):48-52.
[2]Babatunde A O,Zhao Y Q.Equilibrium and kinetic analysis of phosphorus adsorption from aqueous solution using waste alum sludge[J].Journal of Hazardous Materials,2010,184(1):746-752.
[3]高思佳,王昌辉,裴元生.热活化和酸活化给水处理厂废弃铁铝泥的吸磷效果[J].环境科学学报,2012,32(3):606-611.
[4]王宇,谌建宇,李小明,等.镧改性粉煤灰合成沸石的同步脱氨除磷研究[J].中国环境科学,2011,31(7):1152-1158.
[5]Meng X,Huang H,Shi L.Reactive mechanism and regeneration performance of Ni Zn O/Al2O3-diatomite adsorbent by reactive adsorption desulfurization[J].Industrial&Engineering Chemistry Research,2013,52(18):6092-6100.
[6]董延茂,郭叶书,江建军,等.改性氧化镁脱硫废渣协效阻燃环氧树脂的研究[J].环境科技,2012,25(3):16-20.
[7]王宗霞,曾路,王小波,等.硅藻土在扫描电镜下的微观形貌[J].电子显微学报,2006,25(增刊):345-346.
[8]吴蕾,陈云峰.改性硅藻土用于巢湖水脱磷研究[J].环境工程学报,2011,5(4):777-782.
[9]徐丰果,罗建中,凌定勋.废水化学除磷的现状与进展[J].工业水处理,2003,23(5):18-20.
[10]陈静霞,李咏梅.鸟粪石沉淀法预处理高氨氮废水的镁盐研究[J].环境工程学报,2011,5(12):2663-2667.
[11]刘阳,赵丹,董延茂,等.改性硅藻土除磷剂的研究进展[J].污染防治技术,2012,25(4):23-26.
[12]苏营营,于艳卿,杨沛珊,等.纳米Ti O2/硅藻土光催化降解蒽醌染料废水的研究[J].中国环境科学,2009,29(11):1171-1176.
[13]陈敏东,王洪艳,刘宝生,等.镁铝水滑石固载重铬酸钾及其氧化性能[J].环境化学,2008,27(5):591-595.
[14]梁艳,赵杰,王来.贝壳的傅立叶变换红外光谱和热分析[J].矿物岩石,2007,27(2):12-16.
[15]孔茜,杜倩.镁铝LDH制备表征及吸附磷酸根离子的性能研究[J].环境科学与技术,2011,34(3):102-104.
[16]陈再明,方远,徐义亮,等.水稻秸秆生物碳对重金属Pb2+的吸附作用及影响因素[J].环境科学学报,2012,32(4):769-776.
[17]刘理华,刘书群,柴永明,等.磷化镍催化剂的制备机理及其加氢脱氮性能[J].燃料化学学报,2013,41(3):335-340.
[18]He G,He L,Zhao Z,et al.Thermodynamic study on phosphorus removal from tungstate solution via magnesium salt precipitation method[J].Transactions of Nonferrous Metals Society of China,2013,23:3440-3447.
[19]崔蒙蒙,王殿升,黄天寅,等.人工合成水铁矿对含磷废水的吸附性能[J].环境科学,2016(9):3498-3507.
[20]李佳,林建伟,詹艳慧,等.镧改性沸石对水中磷酸盐和铵的去除性能[J].上海海洋大学学报,2012,21(5):800-808.
[21]Cui H J,Wang M K,Fu M L,et al.Enhancing phosphorus availability in phosphorus-fertilized zones by reducing phosphate adsorbed on ferrihydrite using rice straw-derived biochar[J].Journal of Soils and Sediments,2011,11:1135-1141.
[22]Yu J,Liang W,Wang L,et al.Phosphate removal from domestic wastewater using thermally modified steel slag[J].Journal of Environmental Sciences,2015,31:81-88.
[23]李坤权,郑正,罗兴章,等.KOH活化微孔活性炭对对硝基苯胺的吸附动力学[J].中国环境科学,2010,30(2):174-179.
[24]陆燕勤,朱丽,何昭菊,等.沸石负载氧化铁吸附剂吸附除磷研究[J].环境工程,2015(4):48-52.