CAJ | 학술논문

研究了在反应表面积相近条件下,纳米与微米级零价铁(Fe~0)降解水相中2,4,6-三氯酚(TCP)的动力学差异.结果表明,纳米与微米级Fe~0降解TCP过程均符合准一级反应动力学,表观反应速率常数K_(obs)分别为0.0165h~(-1)和0.0046h~(-1)其比值(3.6)接近纳米与微米级Fe~0对TCP的初始吸附量比值(2.9).造成2种Fe~0降解与吸附效率差异的丰要原因在于颗粒表面点位单元活性不同.Fe~0对TCP的作用可分为2个阶段:前一阶段非反应点位主导的吸附作用高于反应点位主导的降解作用,后一阶段刚好相反.反应过程中,纳米与微米级Fe~0反戍组体系pH值从初始的5.7分别升至10.5和8.2,体系pH值处于酸性范围时可提高TCP降解速率.纳米Fe~0在反应过程中表面氧化不断增加,其中大部分铁氧化物沉积在颗粒表面,少量以离子态存在于水相中.
연구료재반응표면적상근조건하,납미여미미급령개철(Fe~0)강해수상중2,4,6-삼록분(TCP)적동역학차이.결과표명,납미여미미급Fe~0강해TCP과정균부합준일급반응동역학,표관반응속솔상수K_(obs)분별위0.0165h~(-1)화0.0046h~(-1)기비치(3.6)접근납미여미미급Fe~0대TCP적초시흡부량비치(2.9).조성2충Fe~0강해여흡부효솔차이적봉요원인재우과립표면점위단원활성불동.Fe~0대TCP적작용가분위2개계단:전일계단비반응점위주도적흡부작용고우반응점위주도적강해작용,후일계단강호상반.반응과정중,납미여미미급Fe~0반수조체계pH치종초시적5.7분별승지10.5화8.2,체계pH치처우산성범위시가제고TCP강해속솔.납미Fe~0재반응과정중표면양화불단증가,기중대부분철양화물침적재과립표면,소량이리자태존재우수상중.
The differences of degradation kinetics of 2,4,6-trichiorophenol (TCP) by nanometer-aud 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 (K_(obs)) 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 FeO was 2.9, which was close to that of K_(obs) (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 fi'om 5.7 to 10.5 and 8.2 in the reaction with nanometer- and micrometer-sized Fe~0, respectively. Comparatively, the rate of TCP degradation was enhanced in the low pH. The surface oxidation on Fe~0 (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.