Abstract  In the present study, photocatalytic decomposition of N-methyl-2-pyrrolidone (NMP) using light sources of UVA, UVC and UVLED was investigated. The effects of different parameters such as NMP initial concentration, pH value, catalyst loading, inorganic salts and the type of light sources on the reaction rate were evaluated, and optimum conditions were determined. The results of experiments showed that catalyst loading of 0.9 g/1 TiO sub(2) was the optimum and further increase in the TiO sub(2) loading reduced removal efficiency. The highest photodegradation reaction rate was obtained in neutral condition rather than acidic or alkaline condition. Furthermore, the effects of inorganic salts were investigated. Result showed that photocatalytic degradation rate was affected significantly in the presence of bicarbonate and chloride. The experimental data showed that the photocatalytic degradation of NMP can be simulated by using pseudo-first-order reaction rate expression. The apparent rate constant (k sub(obs)) over TiO sub(2) photocatalyst with 254 nm ultraviolet lamp (UVC), 365 nm ultraviolet lamp (UVA), and UVLED were 0.0454, 0.0205 and 0.0125 min super(-1) respectively.

Abstract  Rate constants for the atmospheric reactions of 1-methyl-2-pyrrolidinone with OH radicals, NO3 radicals and O-3 have been measured at 296 +/- 2 K and atmospheric pressure of air, and the products of the OH radical and NO3 radical reactions investigated. Using relative rate techniques, rate constants for the gas-phase reactions of OH and NO3 radicals with 1-methyl-2-pyrrolidinone of (2.15 +/- 0.36) x 10(-11) cm(3) molecule(-1) s(-1) and (1.26 +/- 0.40) x 10(-13) cm(3) molecule(-1) s(-1), respectively, were measured, where the indicated errors include the estimated overall uncertainties in the rate constants for the reference compounds. An upper limit to the rate constant for the O-3 reaction of < 1 x 10(-19) cm(3) molecule(-1) s(-1) was also determined. These kinetic data lead to a calculated tropospheric lifetime of 1-methyl-2- pyrrolidinone of a few hours, with both the daytime OH radical reaction and the nighttime NO3 radical reaction being important loss processes. Products of the OH radical and NO3 radical reactions were analyzed by gas chromatography with flame ionization detection and combined gas chromatography-mass spectrometry. N-methylsuccinimide and (tentatively) 1-formyl-2-pyrrolidinone were identified as products of both of these reactions. The measured formation yields of N-methylsuccinimide and 1-formyl-2-pyrrolidinone were 44 +/- 12% and 41 +/- 12%, respectively, from the OH radical reaction and 59 +/- 16% and similar to 4%, respectively, from the NO3 radical reaction. Reaction mechanisms consistent with formation of these products are presented. (C) 1999 Elsevier Science Ltd. All rights reserved.

Abstract  The dynamic industrial development during the past decade has brought about a rapid increase in the quantity of industrial waste products discharged into a watercourse. Most of them consist of organic and inorganic matter. Among the various types of organic pollutants entering a water stream, solvents have recently come to the forefront. Organic solvents in general, and N-methylpyrrolidone (NMP) in particular, are widely used in many industrial processes. It follows that NMP becomes increasingly frequent in wastewater discharges.

Abstract  N-Methylpyrrolidone (NMP), a kind of nitrogen-containing heterocyclic pollutant, is widely used in chemical industry. Microbial degradation is an important environmental fate process in soil and water, however, the microbial metabolic mechanism is still unknown. Strain NMD-4, capable of utilizing NMP as the sole source of carbon and nitrogen, was isolated from the activated sludge of a pesticide plant in Jiangsu, China, and identified as Paracoccus sp. based on its physiological biochemical properties, as well as 16S rRNA gene sequence analysis. The degradation characteristic of NMP by strain NMD-4 was studied in a liquid culture, and the metabolic pathway of NMP by the strain was investigated. Two metabolites, 1-methyl-2,5-pyrrolidinedione and succinic acid, were detected and identified by liquid chromatographymass spectrometry analysis, and a plausible microbial degradation pathway of NMP was proposed by the first time. (C) 2014 Elsevier Ltd. All rights reserved.