Photocatalytic reduction of Cr(VI) and Ni(II) in aqueous solution by synthesized nanoparticle ZnO under ultraviolet light irradiation: a kinetic study
Photocatalytic reduction of Cr(VI) and Ni(II) in aqueous solution by synthesized nanoparticle ZnO under ultraviolet light irradiation: a kinetic study
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DOI：
10.1080/09593330.2010.543933
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发表时间：
2011-06
影响因子：
2.8
通讯作者：
M. Siboni;Mohammad Taghi Samadi;Jae-Kyu Yang;Seung-Mok Lee
中科院分区：
文献类型：
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作者：
M. Siboni;Mohammad Taghi Samadi;Jae-Kyu Yang;Seung-Mok Lee
研究了合成的纳米ZnO在紫外光照射下对水中Cr（VI）和Ni（II）的光催化去除。首先，采用有机化学抑制剂，采用化学法制备纳米氧化锌。考察了溶液pH、ZnO投加量、接触时间、Cr（VI）和Ni（II）初始浓度等因素对纳米ZnO去除Cr（VI）和Ni（II）的影响。在近中性pH下观察到Cr（VI）和Ni（II）的最大去除，因为ZnO在极低和极高pH值下的降低的光催化活性源于催化剂的酸性/光化学腐蚀和/或Zn（OH）2的表面钝化。随着ZnO投加量的增加，Cr（VI）和Ni（II）的去除效率不断提高，但由于用于光催化反应的入射UV光的阻挡增加，在1.25 g/l以上逐渐降低。确定了最佳ZnO用量为1 g/l。Cr（VI）和Ni（II）的去除效率随着初始Cr（VI）和Ni（II）浓度的增加而降低，这是由于ZnO表面上的反应位点减少而导致的对ZnO表面的抑制作用增加。
Photocatalytic removal of Cr(VI) and Ni(II) from aqueous solution using synthesized nanoparticle ZnO under ultraviolet (UV) light irradiation was studied in this work. Firstly, nanoparticle ZnO was prepared by the chemical method with an organic chemical inhibitor. Then removal efficiency of Cr(VI) and Ni(II) by nanoparticle ZnO was investigated with variation of the solution pH, ZnO dosage, contact time and initial Cr(VI) and Ni(II) concentration. Maximum removal of Cr(VI) and Ni(II) was observed at near‐neutral pH because the reduced photocatalytic activity of ZnO at exceedingly low and high pH values originates from either acidic/photochemical corrosion of the catalyst and/or surface passivation with Zn(OH)2. As the ZnO dosage increased, the removal efficiency of Cr(VI) and Ni(II) was continuously enhanced, but was gradually decreased above 1.25 g/l due to the increased blockage of the incident UV light used for the photocatalytic reaction. The optimum ZnO dosage was determined as 1 g/l. Removal efficiencies of Cr(VI) and Ni(II) decreased as initial Cr(VI) and Ni(II) concentration increased, due to an increased inhibition effect on the surface of ZnO resulting from the decreased reaction sites on the surface of ZnO required for the further photocatalytic reaction.