基于ZIF的Ce掺杂ZnO光催化剂催化降解亚甲基蓝废水研究
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摘要
以硝酸锌、二甲基咪唑(制备沸石咪唑酯骨架结构材料(ZIF)的主要原料)、以及硝酸铈等制备了Ce掺杂的Zn O光催化剂(即Ce-ZnO),对催化剂进行了XRD,SEM,EDS等表征分析,考察了Ce掺杂量、废水初始pH等对亚甲基蓝降解影响,用UV-Vis(可见-紫外光谱)对亚甲基蓝降解液进行了分析。研究表明,与ZIF为前驱体的Zn O的形貌和晶体结构类似,Ce掺杂的Zn O催化剂仍为方形颗粒微纳米材料(颗粒尺寸约100 nm)、Zn O为六方晶系纤锌矿结构,但颗粒尺寸减小。掺杂1%的Ce可使Zn O的光催化剂活性提高(光催化剂降解亚甲基蓝的反应速率提高了31%),且具有较好的重复利用性能。Ce-ZnO光催化剂催化降解亚甲基蓝的反应符合一级反应动力学,弱碱性(pH≈10)环境有利于亚甲基蓝光催化剂降解,亚甲基蓝在光催化反应中其显色基团、芳香基团被分解并产生了酸性物质,亚甲基蓝被有效降解。
Ce-doped ZnO photocatalyst(Ce-ZnO) was prepared by zinc nitrate, dimethylimidazole(the main raw material for ZIF) and cerium nitrate. The catalysts were characterized by XRD, SEM and EDS. The effects of Ce content and initial pH of wastewater on the degradation of methylene blue were investigated. Methylene blue degradation solution was analyzed by UV-Vis(visible UV spectrum). The results show that, similar to the morphology and crystal structure of ZnO with ZIF as precursor, the Ce-doped ZnO catalyst is still a square particle micro-nano material(particle size about 100 nm), and the ZnO is a hexagonal wurtzite structure, but the particle size decreases. Doping 1% Ce can improve the photocatalytic activity of ZnO(the reaction rate of photocatalytic degradation of methylene blue increased by 31%) and has good reuse performance. The photocatalytic degradation of methylene blue by Ce-ZnO photocatalyst follows the first-order reaction kinetics. The weak alkaline environment(about pH=10) is favorable for the degradation of methylene blue photocatalyst. The chromogenic and aromatic groups of methylene blue are decomposed into acidic substances in the photocatalytic reaction, and the methylene blue is effectively degraded.
Ce-doped ZnO photocatalyst(Ce-ZnO) was prepared by zinc nitrate, dimethylimidazole(the main raw material for ZIF) and cerium nitrate. The catalysts were characterized by XRD, SEM and EDS. The effects of Ce content and initial pH of wastewater on the degradation of methylene blue were investigated. Methylene blue degradation solution was analyzed by UV-Vis(visible UV spectrum). The results show that, similar to the morphology and crystal structure of ZnO with ZIF as precursor, the Ce-doped ZnO catalyst is still a square particle micro-nano material(particle size about 100 nm), and the ZnO is a hexagonal wurtzite structure, but the particle size decreases. Doping 1% Ce can improve the photocatalytic activity of ZnO(the reaction rate of photocatalytic degradation of methylene blue increased by 31%) and has good reuse performance. The photocatalytic degradation of methylene blue by Ce-ZnO photocatalyst follows the first-order reaction kinetics. The weak alkaline environment(about pH=10) is favorable for the degradation of methylene blue photocatalyst. The chromogenic and aromatic groups of methylene blue are decomposed into acidic substances in the photocatalytic reaction, and the methylene blue is effectively degraded.
引文
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[15]曹渊,王亚涛,徐彦芹,等.微波诱导燃烧法制备稀土离子掺杂氧化锌纳米材料[J].硅酸盐通报,2012,31(5):1318-1322.
[2]史冉冉,王宝辉,苑丹丹.难降解有机废水处理技术研究进展[J].工业催化,2014,22(9):666-670.
[3]赵天.Fe2O3,Zn0及Ce元素掺杂纳米材料的光催化和抑菌性能研究[D].南宁:广西大学,2017.
[4]Rajesh D,Vara B,Sunandana C S.Two-step synthesis and characterization of ZnO nanoparticles[J].Physica B,2012,407:4537-4539.
[5]殷巧巧,乔儒,童国秀.离子掺杂氧化锌光催化纳米功能材料的制备及其应用[J].化学进展,2014,26(10):1619-1632.
[6]宁轲,孙玉梅,陈磊.MOF结构ZnO的制备及其在光催化的应用[J].赤峰学院学报,2017,33(10):31-34.
[7]Joshi Z.Size effects on electrical properties of sol-gel grown chromium doped zinc oxide nanoparticles[J].Journal of Materials Science&Technology,2018.34:488-495.
[8]汪应灵.Ce掺杂ZnO纳米晶的光催化性能研究[J].人工晶体学报,2011,40(4):917-920.
[9]梁春燕.基于Ag2S03/AgBr的复合可见光催化剂的制备及对有机染料的降解[D].长沙:湖南师范大学,2016.
[10]郭娇,张亚昆,陈改荣,等.不同溶剂ZIF-8基制备ZnO及可见光催化性能研究[J].化学研究与应用,2018,30(2):304-308.
[11]张瑞昌,章海波,涂晨,等.pH、离子强度及电解质种类对纳米氧化锌聚集和溶解的影响[J].环境化学,2014,33(11):1822-1827.
[12]刘明明,吕文苗,史秀锋,等.不同方法合成的沸石咪唑酯骨架结构材料(ZIF-8)的表征和催化性能[J].无机化学报,2014,30(3):579-584.
[13]马宏文,矫立男,杨雪,等.固相法合成纳米ZnO及其光催化性能研究[J].化学与生物工程,2006,23(4):17-21.
[14]韩帅,王海芳,侯彬,等.水热合成法制备光催化剂氧化锌及光催化降解效果研究[J].化学与生物工程,2015,43(1):173-175.
[15]曹渊,王亚涛,徐彦芹,等.微波诱导燃烧法制备稀土离子掺杂氧化锌纳米材料[J].硅酸盐通报,2012,31(5):1318-1322.