BiPO_4纳米棒制备及光催化降解罗丹明B

Synthesis of BiPO_4 and its photocatalytic degradation rhodamine B toxic organic pollutants

采用水热法,在不同pH(1.0—11.0)条件下制备了磷酸铋(BiPO4)纳米催化剂,并运用X射线衍射仪,扫描电子显微镜,比表面仪和循环伏安法对催化剂进行了初步表征,说明pH是影响BiPO4催化剂比表面积和结晶度的重要因素.在紫外光(λ≤387 nm)照射下,以染料罗丹明B(Rhodamine,RhB)作为目标化合物,研究了不同pH制备条件下BiPO4降解RhB的光催化特性.结果表明:在pH=1.0条件下,制备所得的BiPO4为高结晶度的单斜相,具有完整的一维棒状结构,能在80 min内将初始浓度为1.25×10-5mol·L-1的RhB完全脱色,18 h后对初始浓度为7.25×10-5mol·L-1RhB矿化率可达99.9%.催化剂结晶度和晶型是影响其光催化活性的重要因素.采用酶催化及荧光分析法,跟踪测定了光催化反应过程中产生的双氧水(H2O2)和羟基自由基(·OH)等氧化物种,表明其光催化反应涉及羟基自由基反应历程.

BiPO4 nanorods were synthesized under different pH conditions using hydrothermal method. The BiPO4 nanorods were characterized using X ray diffraction （XRD）, scanning electron microscope （SEM）, specific surface area analyzer（BET） and cyclic voltammetry （CV）. The results indicate that the prepared BiPO4 is monoclinic phase and has completely rod-like structure when the reaction was at pH 1. Under ultraviolet irradiation （A ≤387 nm）, rhodamine B （RhB） was used as the target compound to study the photocatalytic activity of catalyst BiPO4. It showes that RhB was decolorized in 80 min and the mineralization rate reached 99.9% in 18 h, indicating that BiPO4 nanorods have good photocatalytic activity for the photo-degradation of RhB. The crystallinity and crystal form are the important factors that affect the photocatalytic activity. To reveal the degradation mechanism of BiPQ nanorods/RhB system, the concentration of H2O2 and hydroxyl radical （ ~ OH） were determined by enzyme catalysis and fluorescence analysis methods. It indicates that this system primarily involves ~ OH oxdiation process.