采用微乳液法制备出粒径约为80 nm,主要成分为α-Fe的纳米铁粒子。纳米铁具有极高的活性,在无氧环境中,室温、中性条件下与初始质量浓度为30、50、80、120 mg/L的NO3--N振荡反应30 m in,即可获得90%以上的脱硝率。零价纳米铁去除硝酸盐...采用微乳液法制备出粒径约为80 nm,主要成分为α-Fe的纳米铁粒子。纳米铁具有极高的活性,在无氧环境中,室温、中性条件下与初始质量浓度为30、50、80、120 mg/L的NO3--N振荡反应30 m in,即可获得90%以上的脱硝率。零价纳米铁去除硝酸盐氮的一系列批实验结果表明:硝酸盐与纳米铁反应为非一级动力学反应,硝酸盐氮浓度随时间单调减少,氨氮浓度随时间单调升高,而亚硝酸盐氮的浓度在反应过程中出现极大值,由动力学分析可知其具有连续反应的突出特征,并以此对反应路径进行了探讨。提出纳米铁与硝酸盐反应是氧化还原与吸附作用同时存在且主要产物为氨氮的观点。展开更多
Nanoscale iron was detected by TEM, X-ray diffraction and X-ray photoelectron spectroscopy. It was found that the size of the nanoscale iron particles is in the range of 30?40 nm according to TEM image, and it contain...Nanoscale iron was detected by TEM, X-ray diffraction and X-ray photoelectron spectroscopy. It was found that the size of the nanoscale iron particles is in the range of 30?40 nm according to TEM image, and it contains abundant Fe3O4 as passivating layers on the surface of the core-shell structure. To improve its performance, dilute HCl was used for the removal of the passivating layers, and the degradation of 2,4-dichlorophenol (2,4-DCP) was measured for the nanoscale iron samples treated and untreated. Experimental results demonstrated that the removal of 2,4-DCP by untreated nanoscale iron is mainly due to the adsorption of 2, 4-DCP by nanoscale iron, and there are no degradation products detected by HPLC in the process. However, excellent dechlorination of 2,4-DCP was gained by HCl-treated nanoscale iron, and 2-chlorophenol, 4-chlorophenol and phenol were detected during the process. It was concluded that dechlorination is the key reaction pathway for the degradation of 2,4-DCP by activated nanoscale iron, and phenol is found to be the main product.展开更多
文摘采用微乳液法制备出粒径约为80 nm,主要成分为α-Fe的纳米铁粒子。纳米铁具有极高的活性,在无氧环境中,室温、中性条件下与初始质量浓度为30、50、80、120 mg/L的NO3--N振荡反应30 m in,即可获得90%以上的脱硝率。零价纳米铁去除硝酸盐氮的一系列批实验结果表明:硝酸盐与纳米铁反应为非一级动力学反应,硝酸盐氮浓度随时间单调减少,氨氮浓度随时间单调升高,而亚硝酸盐氮的浓度在反应过程中出现极大值,由动力学分析可知其具有连续反应的突出特征,并以此对反应路径进行了探讨。提出纳米铁与硝酸盐反应是氧化还原与吸附作用同时存在且主要产物为氨氮的观点。
基金supported by the National Natural Science Foundation of China (Grant Nos. 20677073,20537020)the Major State Basic Re-search Development Program of China (Grant No. 2007CB407304)
文摘Nanoscale iron was detected by TEM, X-ray diffraction and X-ray photoelectron spectroscopy. It was found that the size of the nanoscale iron particles is in the range of 30?40 nm according to TEM image, and it contains abundant Fe3O4 as passivating layers on the surface of the core-shell structure. To improve its performance, dilute HCl was used for the removal of the passivating layers, and the degradation of 2,4-dichlorophenol (2,4-DCP) was measured for the nanoscale iron samples treated and untreated. Experimental results demonstrated that the removal of 2,4-DCP by untreated nanoscale iron is mainly due to the adsorption of 2, 4-DCP by nanoscale iron, and there are no degradation products detected by HPLC in the process. However, excellent dechlorination of 2,4-DCP was gained by HCl-treated nanoscale iron, and 2-chlorophenol, 4-chlorophenol and phenol were detected during the process. It was concluded that dechlorination is the key reaction pathway for the degradation of 2,4-DCP by activated nanoscale iron, and phenol is found to be the main product.
