纳米ZnO室温选择氧化H_2S特性的研究

Study on selective oxidation of H_2S with nanometer ZnO at room temperature

碱式碳酸锌在不同焙烧温度下制得的纳米ZnO具有六方晶系纤锌矿结构,平均粒径为15.4nm、19.1nm、22.9nm和33nm,以其为脱硫剂,对H2S室温脱硫性能进行了研究。利用XRD和XPS技术对脱硫反应前后的样品进行了表征。实验结果表明,纳米ZnO的脱硫性能随粒径的增大而降低,常温、常压下,260℃焙烧的纳米ZnO对HS有高的去除率,并且HS可选择性地被氧化为单质硫。

Nanometer sized ZnO with average particle diameters of 15.4 nm, 19. 1 nm, 22.9 nm and 33 nm were prepared by calcination at different temperatures. Their desulfurization behavior and selective oxidation of H2S at room temperature were studied, and compared with commercial ZnO. Properties of nanometer ZnO before and after reactions were characterized by XRD and XPS. XRD results show that there is not ZnS peak detected after reaction, and in the presence of oxygen sulfur and one unknown product are formed, but without oxygen two unknown products are found. In the absence of oxygen, the desulfurization abilities of ZnO decrease,and the product color changes from brown, orange to yellow with the increase of ZnO diameter. The brown and orange products are unstable in air. In the presence of oxygen, however, the desulfurization mechanism of nanometer sized ZnO is obviously different. Nanometer sized ZnO can catalyze the oxidation of H2S to sulfur at room temperature. ZnO particle size also gives great influence on this process.