摘要
针对零价铁易团聚、氧化和钝化的缺陷,选用海泡石为载体、过渡金属镍为催化剂,制备了一种克服以上缺陷的海泡石负载铁镍复合材料(用Fe/Ni-SEP表示),研究了该材料还原水中对氯硝基苯的还原途径、机制及pH与温度的影响。研究结果表明,在30℃下用2g·L^-1投加量的Fe/Ni-SEP去除初始浓度为10mg·L^-1的对氯硝基苯溶液,120min时有94.3%的对氯硝基苯被还原成苯胺。去除过程符合L-H模型,说明去除为还原与吸附的协同作用,其中k1>>k2,因此吸附为速率决定步骤。还原途径与去除机制为:Fe/Ni-SEP中零价铁作为电子供体将硝基还原为胺基,金属镍将零价铁的腐蚀产物H2转化为活性氢,活性氢作用于苯环上的C-Cl键,使对氯苯胺加氢脱氯变成苯胺。升高温度加快了传质速率,且利于反应物越过能垒,使反应速率加快。pH为3~7时,利于发生还原脱氯反应。
A sepiolite supported Fe/Ni (Fe/Ni-SEP) nano composite was prepared with transition metal nickel as catalyst and sepiolite as a carrier to overcome the defects of zero-valent iron, which is easy to aggregate, be oxidized and passivate. The reduction pathway, mechanism and the effects of pH and temperature on the reduction of p-chloronitrobenzene in water by this material were studied. The results show that when 2g·L^-1 of Fe/Ni-SEP was used to remove the parachloronitrobenzene solution with initial concentration of 10mg·L^-1 at 30℃, 94.3% of parachloronitrobenzene was reduced to aniline at reaction time of 120 min.The removal process is consistent with the L-H model, indicating that the removal is a synergistic effect of reduction and adsorption. Due to the k1>>k2 , absorption is the rate-determining step. The reduction process and removal mechanism are as follows: zero-valent iron as an electron donor in Fe/Ni-SEP reduces the nitro group to amine group, and the metal Ni converts the corrosion product H2 of zero-valent iron into an active hydrogen, which attacks on the C-Cl bond on benzene ring, so that the hydrodechlorination of parachloroaniline becomes aniline. Increasing the temperature accelerates the mass transfer rate, and the reaction rate increases as the reactants cross the energy barrier.When the pH is in the range of 3~7, it is conducive to the reduction dechlorination reaction.
作者
李津涛
刘红
解倩倩
范先媛
LI Jintao;LIU Hong;XIE Qianqian;FAN Xianyuan(College of Resource and Environmental Engineering,Wuhan University of Science and Technology,Wuhan 430081,China;Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources,Wuhan University of Science and Technology,Wuhan 430081,China)
出处
《黑龙江大学自然科学学报》
CAS
2019年第3期321-327,共7页
Journal of Natural Science of Heilongjiang University
基金
国家自然科学基金重点项目(41230638)
湖北省环保厅科研项目(2017HB08)
