State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
Environ Sci Technol. 2012 May 1;46(9):5067-76. doi: 10.1021/es204519d. Epub 2012 Apr 18.
The herbicide atrazine is a common pollutant in reservoirs and other sources of drinking water worldwide. The adsorption of atrazine from water onto zeolites CBV-720 and 4A, mesoporous silica MCM-41, quartz sand, and diatomite, and its microwave-induced degradation when sorbed on these minerals, were studied. Dealuminated HY zeolite CBV-720 exhibited the highest atrazine sorption capacity among the mineral sorbents because of its high micropore volume, suitable pore sizes, and surface hydrophobicity. Atrazine sorbed on the minerals degraded under microwave irradiation due to interfacial selective heating by the microwave, while atrazine in aqueous solution and associated with PTFE powder was not affected. Atrazine degraded rapidly in the micropores of CBV-720 under microwave irradiation and its degradation intermediates also decomposed with further irradiation, suggesting atrazine could be fully mineralized. Two new degradation intermediates of atrazine, 3,5-diamino-1,2,4-triazole and guanidine, were first identified in this study. The evolution of degradation intermediates and changes in infrared spectra of CBV-720 after microwave irradiation consistently indicate the creation of microscale hot spots in the micropores and the degradation of atrazine following a pyrolysis mechanism. These results indicate that microporous mineral sorption coupled with microwave-induced degradation could serve as an efficient treatment technology for removing atrazine from drinking water.
除草剂莠去津是世界范围内水库和其他饮用水源中的常见污染物。研究了莠去津从水中吸附到沸石 CBV-720 和 4A、介孔硅 MCM-41、石英砂和硅藻土上，以及其在这些矿物上吸附时的微波诱导降解。由于具有高微孔体积、合适的孔径和表面疏水性，脱铝 HY 沸石 CBV-720 表现出了在这些矿物吸附剂中最高的莠去津吸附容量。由于微波的界面选择性加热，吸附在矿物上的莠去津在微波辐射下降解，而水溶液中的莠去津和与 PTFE 粉末结合的莠去津不受影响。莠去津在微波辐射下迅速在 CBV-720 的微孔中降解，其降解中间体也随着进一步的辐射而分解，表明莠去津可以完全矿化。本研究首次鉴定出莠去津的两种新的降解中间体，3,5-二氨基-1,2,4-三唑和胍。CBV-720 微波辐照后降解中间体的演变和红外光谱的变化一致表明，在微孔中产生了微尺度热点，并且莠去津按照热解机理进行降解。这些结果表明，微孔矿物吸附与微波诱导降解相结合可以作为一种从饮用水中去除莠去津的有效处理技术。
