title: Effective degradation of para-chloronitrobenzene through a sequential treatment using zero-valent iron reduction and Fenton oxidation.
abstract: In this study, zero-valent iron (ZVI) was used to pretreat para-chloronitrobenzene (p-CNB), and the major product was para-chloroaniline (p-CAN). By adding H(2)O(2) directly, further p-CAN degradation can be attributed to Fenton oxidation because ferrous ions (Fe(2+)) released during the ZVI corrosion could be used as an activator for H(2)O(2) decomposition. In the reduction process, the reduction efficiency of p-CNB as well as Fe(2+) concentration increased with increasing iron dosage and decreasing solution pH. Under the optimal conditions, 25 mg L(-1) of p-CNB could be transformed in 3 h when initial solution pH was 3.0 and ZVI dosage was 2.0 g L(-1). A sufficient amount of Fe(2+) (50.4 mg L(-1)) was obtained after the above reaction to activate H(2)O(2). In the Fenton process, the oxidization of p-CAN was also more effective in acidic conditions and it increased with increasing H(2)O(2) concentration. The control experiments showed that the sequential treatment was more effective than Fenton oxidation alone in treating p-CNB wastewater since the removal rate of total organic carbon (TOC) was improved by about 34%. It suggested that the amino function group is more susceptible to oxidative radical attack than the nitro function group. Therefore, sequential treatment using zero-valent iron reduction followed by Fenton oxidation is a promising method for p-CNB degradation.
authors: School of Environmental Science and Engineering, South China University of Technology, Guangzhou, China.
authors: Chen
authors: C
authors: Le
authors: Junqian
authors: J
authors: Liang
authors: Jinhua
authors: J
authors: Wu
authors: Ping
authors: P
authors: Li
authors: Xiangde
authors: X
authors: Wang
authors: Nengwu
authors: N
authors: Zhu
authors: Pingxiao
authors: P
authors: Wu
authors: Bo
authors: B
authors: Yang
mesh_terms: D002681:China; D052918:Environmental Restoration and Remediation; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D009578:Nitrobenzenes / Q000032:analysis*; D010084:Oxidation-Reduction; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: C045076:Fenton's reagent; D009578:Nitrobenzenes; D014874:Water Pollutants, Chemical; D006861:Hydrogen Peroxide; C010407:4-chloronitrobenzene; D007501:Iron