Department of Chemistry and Biochemistry, California State University-Long Beach, 1250 Bellflower Boulevard, Long Beach, CA 90840-3903, USA.
Chemosphere. 2010 Sep;81(3):339-44. doi: 10.1016/j.chemosphere.2010.07.027. Epub 2010 Aug 8.
Methyl isothiocyanate (MITC), a toxic and corrosive skin and respiratory irritant, is a common soil fumigant byproduct which has become an atmospheric, aqueous, and soil contaminant. The work described here examines the degradation and potential removal of MITC from contaminated waters via free radical reactions. We have measured the oxidizing hydroxyl radical ((·)OH) reaction rate constant with MITC over a range of temperatures relevant to wastewater treatment conditions, determining a room temperature value of (5.69±0.56) x 10(8)M(-1)s(-1) and a corresponding Arrhenius activation energy of 12.90±0.82 kJ mol(-1). Hydroxyl radical reaction efficiencies with MITC in pure water, an associated matrix of model real-world waters, and a reverse osmosis permeate water have also been determined. While solutions containing these constituents had significantly decreased MITC removal efficiencies (5.5-14.7%) as compared to pure water (54.4±3.4%), relative rate calculation corrections showed that the (·)OH radical efficiencies for solutions containing DOM were the same as in pure water. However, the slightly higher efficiencies for carbonate-containing solutions indicated that some additional MITC degradation occurred from carbonate radical reactions.
甲基异硫氰酸酯（MITC）是一种有毒、腐蚀性的皮肤和呼吸道刺激物，是一种常见的土壤熏蒸剂副产物，已成为大气、水和土壤污染物。这里描述的工作研究了通过自由基反应从受污染的水中降解和去除 MITC 的潜力。我们已经在与废水处理条件相关的一系列温度下测量了 MITC 与氧化羟基自由基（(·)OH）的反应速率常数，确定了室温下的值为(5.69±0.56)x10(8)M(-1)s(-1)，相应的阿伦尼乌斯活化能为 12.90±0.82 kJ mol(-1)。还测定了 MITC 在纯水中、相关模型实际水样的基质中和反渗透渗透水中的羟基自由基反应效率。与纯水中的（54.4±3.4%）相比，含有这些成分的溶液中 MITC 的去除效率（5.5-14.7%）显著降低，但相对速率计算校正表明，含有 DOM 的溶液中的（·）OH 自由基效率与纯水中相同。然而，含碳酸盐溶液的效率略高，表明碳酸盐自由基反应导致了一些额外的 MITC 降解。
