The oxidative degradation of 2-mercaptobenzothiazole at the interface of beta-MnO2 and water.
To investigate the oxidative degradation of organic pollutants at the interface of manganese oxides and water, beta-MnO2 was prepared and its crystal structure and the specific surface area were examined by X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) methods, respectively. 2-Mercaptobenzothiazole (MBT) as a model chemical was used to study its oxidative degradation reaction in beta-MnO2 suspension. The experimental results showed that MBT was effectively degraded and mineralized into SO4(2-) and NO3- by beta-MnO2. In the meantime, it was found that beta-MnO2 could be reductively dissolved, and aqueous and adsorbed Mn2+ was generated. The kinetics of MBT degradation by beta-MnO2 is a function of initial MBT concentration, beta-MnO2 dosage and pH value. At pH 4.6, apparent reaction orders with respect to initial MBT concentration and beta-MnO2 dosage were determined to be 0.88 and 0.27, respectively. The initial reaction rate (rinit) is of pH dependence with a reaction order of -0.36. The thermodynamics of MBT degradation by beta-MnO2 was also investigated, and the apparent activation energy was calculated to be 5.62 kJ/mol. The inhibited effect of carboxylic acids (oxalic, citric, tartaric, and malic acids) or metal ions (Ni2+, Ca2+, Mn2+ and Cr3+) on the oxidative degradation of MBT by beta-MnO2 was also investigated. This investigation will give some new insights for understanding the interaction of organic pollutants with manganese oxides in natural soils and sediments.
Li
Fangbai
F
Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environment and Soil Science, Guangzhou 510650, China. cefbli@soil.gd.cn
Liu
Chengshuai
C
Liang
Chunhua
C
Li
Xiangzhong
X
Zhang
Lijia
L
D052160:Benzothiazoles / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D017895:Manganese Compounds / Q000737:chemistry*; D008670:Metals / Q000737:chemistry; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D052160:Benzothiazoles; D002264:Carboxylic Acids; D017895:Manganese Compounds; D008670:Metals; D010087:Oxides; D014874:Water Pollutants, Chemical; D014867:Water; C027424:manganese oxide; C028000:dibenzothiazyl disulfide