Microwave-assisted carbofuran degradation in the presence of GAC, ZVI and H2O2: Influence of reaction temperature and pH
Microwave-assisted carbofuran degradation in the presence of GAC, ZVI and H2O2: Influence of reaction temperature and pH
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DOI：
10.1016/j.seppur.2010.10.012
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发表时间：
2011-01
影响因子：
8.6
通讯作者：
N. Remya;Jih‐Gaw Lin
中科院分区：
文献类型：
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作者：
N. Remya;Jih‐Gaw Lin
研究了微波辅助颗粒活性炭（GAC）/零价铁（ZVI）/过氧化氢（H2 O2）体系在不同反应温度（30°C、50°C和80°C）和不同pH值（2、4、6、8和10）下对克百威的降解。使用改进的MW反应器（750 W功率和2450 MHz频率）在100 mgL − 1克百威浓度下进行分批实验。较低的MW反应温度，即30°C和50°C，产生了差的克百威降解效率，而在80°C和pH 6下，在所有系统中观察到完全的克百威降解（100%），即MW与GAC、ZVI和H2 O2。在类似条件下，在不含MW的GAC/ZVI/H2 O2存在下，观察到克百威的去除/降解微不足道（2-24%）。在碱性条件下，即pH 8和10（80°C），克百威降解速率加快，在所有微波辅助体系中，克百威在10 min内降解率均达到100%。而在pH 10和80°C条件下，微波辅助GAC和ZVI体系对克百威的降解速度较快（5 min）。使用一级反应动力学对微波辅助系统中的克百威去除进行建模，在微波辅助ZVI系统中获得的最大去除速率常数为4.17min-1。通过水解和氨基甲酸酯基团的去除，在MW辅助的GAC系统中实现了最大86%的克百威矿化。微波辅助系统与其他工艺的能耗比较表明，微波辅助工艺对克百威的降解和矿化具有高效和成本效益。
Carbofuran degradation in microwave (MW)-assisted granular activated carbon (GAC)/zero-valent iron (ZVI)/hydrogen peroxide (H2O2) system(s) was investigated under different reaction temperatures, i.e. 30°C, 50°C and 80°C, and at varying pHs, i.e. 2, 4, 6, 8 and 10. Batch experiments were conducted using a modified-MW reactor (750W power and 2450MHz frequency) at 100mgL−1carbofuran concentration. The lower MW-reaction temperatures, i.e. 30°C and 50°C, have produced poor carbofuran degradation efficiencies whereas complete carbofuran degradation (100%) was observed at 80°C and pH 6 in all the systems, i.e. MW with GAC, ZVI and H2O2. Under the similar conditions, insignificant carbofuran removal/degradation (2–24%) was observed in the presence of GAC/ZVI/H2O2without MW. On the other hand, the carbofuran degradation rate was accelerated under the alkaline pHs, i.e. pH 8 and 10 (at 80°C), and 100% carbofuran degradation was observed within 10min in all the MW-assisted systems. However, the complete carbofuran degradation was accomplished rapidly (5min) in the MW-assisted GAC and ZVI systems under pH 10 and 80°C. Carbofuran removal in the MW-assisted systems was modeled using the first-order reaction kinetics and a maximum removal rate constant of 4.17min−1was obtained in the MW-assisted ZVI system. A maximum of 86% carbofuran mineralization was achieved in the MW-assisted GAC system via hydrolysis and the removal of carbamate group. The comparison of energy consumption in MW-assisted systems with other processes reveals that the MW-assisted process is highly efficient and cost-effective for carbofuran degradation and mineralization.