Abstract:The differences of degradation kinetics of 2,4,6-trichlorophenol (TCP) by nanometer-and micrometer-sized zero-valent iron (Fe0) with approximate surface area in aqueous solution were studied. The results showed that both degradation equations of TCP by nanometer-and micrometer-sized Fe0 were fitted well to the pseudo first-order kinetics. The observed reaction rate constant (Kobs) values were 0.0165 h-1 and 0.0046 h-1, respectively. The ratio of initial adsorption of TCP on the nanometer- to micrometer-sized Fe0 was 2.9, which was close to that of Kobs (3.6). Therefore, it could be concluded that the differences in degradation and adsorption efficiency between the two kinds of zero-valent iron were attributed to the variation of surface site activity from micrometer to nanometer size. In addition, in the case of the TCP degradation by Fe0, the effects of two sites of Fe0 surface could be distinguished in the TCP adsorption and degradation processes. Initially, adsorption mostly induced by non-reactive sites was more important than degradation induced by reactive sites, and subsequently the degradation was dominative. The pH values increased from 5.7 to 10.5 and 8.2 in the reaction with nanometer- and micrometer-sized Fe0, respectively. Comparatively, the rate of TCP degradation was enhanced in the low pH. The surface oxidation on Fe0 (nano) was also increased during the degradation, and a large portion of oxide was deposited on particle surface, while few ionic Fe was dissolved in the suspension.
金盛杨, 王玉军, 李连祯, 周东美, 王慎强. 纳米与微米级零价铁降解2,4,6-三氯酚动力学比较[J]. 中国环境科学, 2010, 30(1): 82-87.
JIN Sheng-Yang, WANG Yu-Jun, LI Lian-Zhen, ZHOU Dong-Mei, WANG Shen-Qiang. Comparison of degradation kinetics of 2,4,6-trichlorophenol using nanometer- and micrometer-sized Fe0. CHINA ENVIRONMENTAL SCIENCECE, 2010, 30(1): 82-87.