ZnO/水葫芦炭复合材料的制备及太阳光催化性能研究

Preparation and photocatalytic performance of ZnO modified water hyacinth carbon composite

以农林废弃物水葫芦制备水葫芦炭,采用浸渍法制备ZnO/C复合光催化剂,考察了光源、负载量及焙烧温度对苯酚光催化降解活性的影响,采用红外光谱、X射线衍射、扫描电镜进行物相表征。结果表明,ZnO均匀分散在水葫芦炭表面,使复合材料不仅具有较高的光催化活性,同时也保留了炭的吸附性。催化剂用量为2 g/L,反应时间240 min,纯ZnO(500℃,2 h)的降解率较低,在太阳光下仅为12%。水葫芦炭(500℃,2 h)的吸附率为37%。5%ZnO/水葫芦炭(500℃,2 h)复合材料在同等条件下降解率为82%。自由基捕获结果说明3种自由基均对光催化降解苯酚提供活性,且氧化能力由强到弱顺序为:羟基自由基(·OH)>光生空穴(h^(+))>过氧化物自由基阴离子(·O_(2)^(-))。同时,利用紫外可见光谱探究了光催化降解苯酚的中间产物,推测了苯酚在ZnO/C复合材料光催化降解机理。

Water hyacinth carbon was prepared from agricultural and forestry waste water hyacinth,and zinc oxide/water hyacinth carbon composites was prepared by impregnation.The influence of light source,load and roasting temperature on phenol photocatalytic degradation activation were investigated.Using FTIR,X-ray diffraction and SEM to conduct phase characterization.The results showed that ZnO in the photocatalytic composite was successfully loaded on water hyacinth carbon and evenly dispersed on the surface of water hyacinth carbon,making the composite not only have good photocatalytic activity,but also retain carbon.The amount of catalyst was 2 g/L and reaction time was 240 min.The degradation rate of zinc oxide(500℃,2 h)prepared was lower,12%under sunlight.The adsorptive activity of water hyacinth charcoal(500℃,2 h)was 37%.Under the same conditions,the catalytic activity of 5%ZnO/water hyacinth carbon composite was better than that of single catalyst.The degradation rate of sunlight was 82%.Results of free radical trapping experiments show all three free radicals are active to the degradation process.The order of oxidation capacity from strong to weak is·OH>h^(+)>·O_(2)^(-).The intermediates of phenol degradation were investigated by UV-Vis and the possible reaction mechanism of phenol removal is proposed.