title: Effects of operational parameters and common ions on the reduction of 2,4-dinitrotoluene by scrap copper-modified cast iron.
abstract: Scrap Cu-modified cast iron (CMCI) is a potent material for the reduction of 2,4-dinitrotoluene (2,4-DNT) by a surface-mediated reaction. However, the effects of operational parameters and common ions on its reduction and final rate are unknown. Results show that the 2,4-DNT reduction was significantly affected by Cu:Fe mass ratio and the optimum m(Cu:Fe) was 0.25%. The slight pH-dependent trend of 2,4-DNT reduction by CMCI was observed at pH 3 to 11, and the maximum end product, 2,4-diaminotoluene (2,4-DAT), was generated at pH 7. Dissolved oxygen (DO) in the water reduced the 2,4-DNT degradation and the formation of 2,4-DAT. CMCI effectively treated high concentrations of 2,4-DNT (60 to 150 mg L(-1)). In addition, varying the concentration of (NH4)2SO4 from 0.001 to 0.1 mol L(-1) improved the efficiency of the reduction process. The green rust-like corrosion products (GR-SO4 (2-)) were also effective for 2,4-DNT reduction, in which Na2CO3 (0.01 to 0.2 mol L(-1)) significantly inhibited this reduction. The repeated-use efficiency of CMCI was also inhibited. Moreover, 2,4-DNT and its products, such as 4A2NT, 2A4NT, and 2,4-DAT, produced mass imbalance (<35%). Hydrolysis of Fe(3+) and CO3 (2-) leading to the generation of Fe(OH)3 and conversion to FeOOH that precipitated on the surface and strongly adsorbed the products of reduction caused the inhibition of CO3 (2-). The 2,4-DNT reduction by CMCI could be described by pseudo-first-order kinetics. The operational conditions and common ions affected the 2,4-DNT reduction and its products by enhancing the corrosion of iron or accumulating a passive oxide film on the reactivity sites.
authors: State Key Laboratory of Pollution Control and Resources Reuse, National Engineering Research Center for Urban Pollution Control, Collaborative Innovation Center of Advanced Technology and Equipment for Water Pollution Control, College of Environmental Science and Technology, Tongji University, Shanghai, 200092, China.
authors: Jin-Hong
authors: JH
authors: Fan
authors: Hong-Wu
authors: HW
authors: Wang
mesh_terms: D003300:Copper / Q000737:chemistry*; D004136:Dinitrobenzenes / Q000032:analysis / Q000737:chemistry*; D052918:Environmental Restoration and Remediation; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D010655:Phenylenediamines / Q000032:analysis / Q000737:chemistry; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification
chemical_list: D003300:Copper; D004136:Dinitrobenzenes; D007501:Iron; D010655:Phenylenediamines; D062065:Wastewater; D014874:Water Pollutants, Chemical; C016403:2,4-dinitrotoluene; C010914:2,4-diaminotoluene