铬取代杂多阴离子PW11O39Cr(Ⅲ)(H2O^4-)可见光催化降解罗丹明B

Visible Photocatalytic Degradation of Rhodamine B Using Keggintype Cr(Ⅲ)-Substituted Heteropolyanion PW_(11)O_(39)Cr(Ⅲ)(H_2O)^(4-)

为了利用太阳光能去除水体有机染料污染物,以Keggin型铬取代杂多阴离子PW11O39Cr(III)(H2O)4-(PW11Cr)为光催化剂, 详细研究在可见光照射下PW11Cr对水体有机染料污染物罗丹明B(RhB)的光催化降解作用, 考察RhB和PW11Cr初始浓度以及溶液pH对RhB可见光催化降解速率的影响, 并通过可见吸收光谱和荧光发射光谱研究水溶液中PW11Cr和RhB的相互作用, 提出PW11Cr光催化作用的机理. 实验结果表明,含有50 μTTmol·L-1 PW11Cr和10 μTTmol·L-1 RhB的水溶液在200 W可见光下照射120 min, RhB的降解率达到100%,总有机碳去除率约32%. 在PW11Cr浓度较大和pH<3.5的酸性条件下, PW11Cr与RhB之间易发生络合, 导致RhB光降解速率变慢,而PW11Cr浓度为50 μTTmol·L-1和溶液接近中性条件下, RhB的光降解速率较快.

In order to remove aquatic organic dye contaminants utilizing the inexpensive and inexhaustible solar energy, the Keggin-type Cr（III）-substituted heteropolyanion PW11O39Cr（III）（H2O）4- （PW11Cr） was used as a photocatalyst. The photocatalytic degradation of rhodamine B （RhB） by PWBB11BBCr under visible light irradiation was investigated in details in this study. At the same time, influences of the initial RhB concen-tration, the PWBB11BBCr concentration and the solution pH on the photocatalytic degradation rate of RhB were also examined. The interaction between PW11Cr and RhB was scrutinized using visible absorption spectrum and fluorescence emission spectrum. A visible photocatalysis mechanism of PW11Cr for RhB photodegrada-tion was proposed. It was found that 100% of RhB degradation and 32% of TOC removal were reached when the solution containing 50 μTTmol？L-1 PW11Cr and 10 μTTmol？L-1 RhB was exposed to visible-light irra-diation for 120 min. The coordination interaction between PW11Cr and RhB occurs readily at pH3.5 and a high PW11Cr concentration, which leads to a slow RhB degradation rate. In contrast, the degradation rate of RhB is rapid at the PW11Cr concentration of 50 μTTmol·L-1 and near neutral solution.