针铁矿光催化染料废水的表面状态与作用机制

Surface State and Mechanism for Photocatalytic Degradation of Dye Wastewater by Goethite

为了解光类芬顿反应时催化剂表面形态与可电离染料分子形态及相互作用,通过实验测定,结合protfit2.1表面络合模拟软件,得到所制备的针铁矿表面位密度为Nt=1.45×10-4mol·g-1,pKa1=4.41和pKa2=6.86,零净质子电荷点pHpzc=5.64。针铁矿光催化降解模拟染料实验结果表明:随pH值升高,降解率下降,pH值为3时针铁矿表面化合态>FeOH+2份额为96.25%、分子态份额为61.31%,脱色效率为65%;pH值为7时>FeOH+2份额为0.11%、分子态份额为0.02%,脱色效率为20%,脱色效率呈现与>FeOH+2及分子态份额正相关。由吸附催化理论推测染料分子与催化剂生成络合物FeIIIRn参与了催化反应的电子转移,形成光化学反应循环。

Abstract： In order to understand the surface morphology of the catalyst and the form of ionizable dye molecules and their interac- tion in Photo Fenton reaction, fitting of experimental determination and the software of Surface complexation model of protfit2.1. we know preparation goethite, the surface density of which is Nt = 1. 45 ×10^-4mol · g-1, pKa1 =4.41 and pKa =6.86, the Zero net proton charge point is pHpzc = 5.64. According to the experiment of photocatalytic degradation of dye goethite, with the increase of pH value, the degradation rate decreases. When the pH is 3, the surface speciation of goethite accounts for 96.25%, molecular state accounts for 61.31%, and decolonization efficiency is 65%. When the pH is 7, the surface speciation of goethite accounts for O. 11%, molecular state accounts for 0.02%, and decolonization efficiency is 20%. The decolorization e^ciency is positive correlation to the molecular share of molecular state. According to the theory of adsorption and catalysis, it is deducted that dyes molecule and complexes FemR, generated by catalyst involves in the catalytic reaction of electron transfer, and results in the formation of photochemical reaction cycle.