g-C3N4/TiO2光催化复合材料制备及其降解印染废水研究

分别利用四异丙醇钛、三乙胺和三聚氰胺制备TiO2和g-C3N4,结合两者制备不同复合比与焙烧温度条件下的g-C3N4/TiO2粉体样品,利用X射线衍射仪和扫描电子显微镜等研究样品表征。以靛蓝类染料模拟废水、偶氮染料4BS、三苯甲烷类染料模拟废水和某印刷厂排放的印染废水为光催化降解对象,研究样品复合比与焙烧温度、光照时间与强度、印染废水初始化学需氧量(COD)值等因素对印染废水降解、COD去除率以及色度脱色率的影响。研究结果显示:光催化复合材料样品为锐钛矿相和金红石相组成的混合晶型;当样品复合比与焙烧温度分别为1.0和350℃时,光催化降解印染废水效果最好,不仅能够确保COD去除率较为稳定,且具有较高重复利用率和稳定性;光照时间越长、光照强度越高,样品COD去除率与色度脱色率越高,且印染废水初始COD值越高,样品COD去除率越低。

Preparation of g-C3N4/TiO2 photocatalytic composite and its degradation of printing and dyeing wastewater

TiO2 and g-C3N4 are prepared by titanium tetraisopropanol, triethylamine and melamine respectively, and g-C3N4/TiO2 powder samples with different composite ratio and roasting temperature are prepared by combining the two. The sample characterization is studied by X-ray diffractometer and scanning electron microscope. The simulated wastewater of indigo dye, azo dye 4 BS, triphenylmethane dye and printing and dyeing wastewater from a printing factory are used as photocatalytic degradation objects, and the effects of the composite ratio of samples and calcination temperature, illumination time and intensity, initial COD value of dyeing wastewater on the degradation, COD removal rate and chroma decolorization rate of dyeing wastewater are studied. The results show that the samples of the photocatalysis composite are of the mixed crystal of anatase and rutile. When the composite ratio of sample and calcination temperature are 1.0 and 350 ℃, the photocatalytic degradation of printing and dyeing wastewater is the best, which can not only ensure that the COD removal rate is relatively stable, but also has high reuse rate and stability. The longer the illumination time is, the higher the illumination intensity is, the higher the removal rate of COD and the decolorization rate of chroma are, and the higher the initial COD value of printing and dyeing wastewater is, the lower the removal rate of COD is.