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Investigation of the kinetics and mechanism of the glycerol chlorination reaction using gas chromatography–mass spectrometry  [PDF]
Journal of the Serbian Chemical Society , 2010,
Abstract: As a primary by-product in biodiesel production, glycerol can be used to prepare an important fine chemical, epichlorohydrin, by the glycerol chlorination reaction. Although this process has been applied in industrial production, unfortunately, less attention has been paid to the analysis and separation of the compounds in the glycerol chlorination products. In this study, a convenient and accurate method to determine the products in glycerol chlorination reaction was established and based on the results the kinetic mechanism of the reaction was investigated. The structure of main products, including 1,3--dichloropropan-2-ol, 2,3-dichloropropan-1-ol, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol and glycerol was ascertained by gas chromatography–mass spectrometry and the isomers of the products were distinguished. Apidic acid was considered as the best catalyst because of its excellent catalytic effect and high boiling point. The mechanism of the glycerol chlorination reaction was proposed and a new kinetic model was developed. Kinetic equations of the process in the experimental range were obtained by data fitting and the activation energies of each tandem reaction were 30.7, 41.8, 29.4 and 49.5 kJ mol-1, respectively. This study revealed the process and mechanism of the kinetics and provides the theoretical basis for engineering problems.
Influencing factors and degradation products of antipyrine chlorination in water with free chlorine
Meiquan Cai,Liqiu Zhang,Fei Qi,Li Feng,
Meiquan Cai
,Liqiu Zhang,Fei Qi,Li Feng

环境科学学报(英文版) , 2013,
Abstract: Owing to its low cost, free chlorine is one of the most common disinfectants for wastewater and drinking water treatment. However, the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades. Antipyrine (ANT), an anti-inflammatory analgesic, has been frequently detected in the aquatic environment. In this work, the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments. The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L, free chlorine dosage from 0.30 to 1.31 mg/L, and pH from 1.5 to 9.0. The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry. The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L, ANT 0.5 mg/L, pH 7.0). Higher oxidant dosage, lower ANT initial concentration and low pH favor the ANT removal. The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one), which can be further chlorinated by free chlorine. In addition, the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.
Determination of Anions in the Products of Ozonation of Reactive Dye by Ion Chromatography

Yediler Ayfer,KETTRUP Antonius,
,梁鑫淼,张青,陈吉平,Yediler Ayfer

色谱 , 2002,
Abstract: A method for the determination of anions in the degradation products of C I Reactive Red 120 by ozonation was investigated. The sample can be pretreated with a Dionex OnGuard P column, which has high selectivity for removing phenols, azo group contaning compounds, aromatic carboxylic aicds etc. For the separation of organic and inorganic anions in the products, the anion exchange chromatograhy with gradient elution of NaOH was used. All the species were detected by both suppressed conductivity and UV absorbance detectors. The sulfate, oxalate, chloride, nitrate and formate could be identified even in very low concentration with ion chromatography, within 18 min, with the recoveries between 91 6%-108 3%. The results indicate that the method is reliable, simple, rapid and especially sensitive. In combining with the determination results of conventional parameters of the solution of Reactive Red 120, a preliminary elucidation of the degradation mechanism is presented.
Ozonation of ethinylestradiol in aqueous-methanolic solution: direct monitoring by electrospray ionization mass spectrometry
Vieira, Karla M.;Nascentes, Clésia C.;Augusti, Rodinei;
Journal of the Brazilian Chemical Society , 2010, DOI: 10.1590/S0103-50532010000500004
Abstract: the ozonolysis of ethinylestradiol (1), a synthetic steroidal estrogen, in an aqueous-methanolic solution was investigated. hplc-uv analyses revealed that 1 was completely consumed after a 20 min reaction time either at ph 5 or 8. esi(-)-ms (electrospray ionization mass spectrometry in the negative ion mode) monitoring also revealed the continuous consumption of 1 (detected as [1 – h]- of m/z 295) concomitantly with the emergence of oxidation products. chemical structures were proposed for these products based on the data of ms and ms/ms (the m/z values and fragmentation profiles of the anionic specie, respectively). these data, in conjunction with the well-established knowledge about the reactivity of organic molecules toward ozone in aqueous solution, were evaluated and an unprecedented reaction route for the ozonation of 1 could thus be suggested. hence, the first step in this reaction sequence was ascribed to involve a 1,3-dipolar cycloaddition of ozone at the phenolic ring of 1 yielding the di-hydroxylated product 2 (detected as [2 – h]- of m/z 311). the loss of acetylene as the unique dissociation channel for [2 – h]- thus confirmed that such hydroxylation occurred at the phenolic ring rather than the acetylenic moiety of 1. subsequent oxidations were proposed to be the origin of a number of other products, all of them bearing the cooh functionally (this was verified by the characteristic loss of co2 during the dissociation of the related deprotonated molecules). the esi(-)-ms records also revealed notable differences between the reaction conducted at ph 5 and 8, i.e. at slightly acid or basic media, respectively.
Partial ozonation of anthracene and characteristic of ozonized products

WU Di,WANG Jianlong,

环境科学学报 , 2005,
Abstract: Partial ozonation of anthracene was carried out. Ozonation process and changes of intermediate products were examined with HPLC and UV. TOC of soluble organics of ozonized products and oxygen uptake rate(OUR) of activated sludge which showed the influence of these organic compounds were also examined. The results indicated that during the ozonation process, anthracene was degraded, and new organic compounds were produced. Ozone could react further with these intermediate products, but could not mineralize them. However, biodegradability of anthracene was improved by ozonation. Therefore, the combination with ozonation and biodegradation would be possible an efficient and economical way to mineralize anthracene in wastewater.
Chloroform formation by chlorination of aqueous algae suspensions: online monitoring via membrane introduction mass spectrometry
Borges, Jo?o T.;Sparrapan, Regina;Guimar?es, José R.;Eberlin, Marcos N.;Augusti, Rodinei;
Journal of the Brazilian Chemical Society , 2008, DOI: 10.1590/S0103-50532008000500021
Abstract: membrane introduction mass spectrometry (mims) was used to perform on-line monitoring of the chloroform formation via the chlorination of aqueous suspensions of several green and blue-green brazilian algae (microcystis panniformis, selenastrum sp., scenedesmus sp., monoraphidium sp. (strain 354), monoraphidium sp. (strain 960), and staurastrum sp.). the influence of major parameters, such as temperature, ph, initial concentration of sodium hypochloride, filtration, and reaction time, on chloroform formation was evaluated. it was verified that the chloroform formation is strongly dependent on the alga type and is favored by high temperatures, ph, sodium hypochloride initial concentration and reaction time. finally, filtered algae samples produce smaller amounts of chloroform in comparison to the rough suspension.
Chlorination disinfection by-products in drinking water and congenital anomalies: review and meta-analyses
Nieuwenhuijsen,Mark J.; Martinez,David; Grellier,James; Bennett,James; Best,Nicky; Iszatt,Nina; Vrijheid,Martine; Toledano,Mireille B.;
Ciência & Saúde Coletiva , 2010, DOI: 10.1590/S1413-81232010000800015
Abstract: this study aims to review epidemiologic evidence of the association between exposure to chlorination disinfection by-products (dbps) and congenital anomalies. all epidemiologic studies that evaluated a relationship between an index of dbp exposure and risk of congenital anomalies were analyzed. for all congenital anomalies combined, the meta-analysis gave a statistically significant excess risk for high versus low exposure to water chlorination or tthm (17%; 95% ci, 3-34) based on a small number of studies. the meta-analysis also suggested a statistically significant excess risk for ventricular septal defects (58%; 95% ci, 21-107), but based on only three studies, and there was little evidence of an exposure-response relationship. it was observed no statistically significant relationships in the other meta-analyses and little evidence for publication bias, except for urinary tract defects and cleft lip and palate. although some individual studies have suggested an association between chlorination disinfection by-products and congenital anomalies, meta-analyses of all currently available studies demonstrate little evidence of such association.
Fatty acids and algal lipids as precursors of chlorination by-products
Yan Liang,Yuen Shan Lui,Huachang Hong,
Yan Liang
,Yuen Shan Lui,Huachang Hong

环境科学学报(英文版) , 2012,
Abstract: Six common algal fatty acids (FAs) with different numbers of double bonds, lipophilic fractions and proteins extracted from the diatom Navicula pelliculosa and algal cells were chlorinated to evaluate their potential in generating disinfection by-products (DBPs). The result showed that the more double bonds in the FAs, the higher the amounts of chloroform and dichloroacetic acid (DCAA) produced, but such a pattern was not observed for trichloroacetic acid (TCAA). Based on the previously reported composition of fatty acids in algal lipids, the DBP generation potentials of algal lipids were calculated. These predicted values were much lower than those measured in the chlorinated algal lipophilic fraction, suggesting unknown lipophilic fraction(s) served as potent DBPs precursors. Another calculation attempted to predict DBP production in algal cells based on algal lipid and protein composition, given quantified measured DBP production per unit algal lipid and proteins. The analysis showed that the observed DBP production was similar to that predicted (< 35% difference), suggesting that algal biochemical compositions may serve as a bioindicator for preliminary estimation of chloroform, DCAA and TCAA formation upon chlorinating algae.
Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: A comparative study
A Caravelli, L Giannuzzi, N Zaritzky
Water SA , 2006,
Abstract: Chlorination is a very useful control method of filamentous bulking in activated sludge systems; however, it favours formation of undesirable compounds such as trihalomethanes. Other oxidants, such as ozone, could be used for bulking control. In view of the fact that chlorine and ozone are both non-selective chemical agents affecting filamentous and floc-forming micro-organisms, the determination of optimum dosage conditions becomes essential to minimise the impact produced on the activated sludge process. In this work, the effects of chlorine and ozone on the biomass concentration of activated sludge and on different parameters that characterise the microbial metabolic activity were compared. The following techniques were applied: Respirometry (oxygen uptake rate); and INT-dehydrogenase activity test carried out both by spectrophotometry (DHAa) and image analysis (DHAi). The respirometric technique and the DHAa test quantified oxidants action on the total respiratory activity of flocs; the image DHAi test was applied to evaluate the specific action of the oxidants on filamentous micro-organisms. Additionally, plate count technique, respirometry and DHAa test were correlated using chlorine and ozone experiments on pure cultures of a floc-forming micro-organism (Acinetobacter anitratus) to compare the effect of the oxidising agents on the metabolic activity and the viability of the micro-organisms. Ozone was found to have more intense antimicrobial action. In activated sludge, ozone reduced total biomass concentration by oxidising various components and causing cell lysis. An equation was proposed to estimate biomass concentration of activated sludge as a function of time and ozone dose rate; in contrast, at the doses applied, chlorine did not reduce the concentration of activated sludge biomass. In activated sludge, adequate conditions for both oxidants were identified under which the respiratory activity of filamentous micro-organisms could be considerably inhibited, causing the lowest possible impact on whole floc metabolic activity. An initial chlorine dose of 7.9 mgCl2·gVSS-1 for a contact time of 5 min (initial pulse= 6.0 mgCl2· -1), and a total ozone dose of 66.0 mgO3·gVSS-1 (ozone dose rate of 3.3 mgO3·gVSS-1·min-1 for a contact time of 20 min) were the most suitable conditions to control filamentous bulking. Water SA Vol.32 (4) 2006: pp.585-595
The assessment of population exposure to chlorination by-products: a study on the influence of the water distribution system
Christelle Legay, Manuel J Rodriguez, Jean Sérodes, Patrick Levallois
Environmental Health , 2010, DOI: 10.1186/1476-069x-9-59
Abstract: In this paper, different approaches to spatially assign available THM and HAA concentrations in drinking water for population exposure assessment purposes are investigated. Six approaches integrating different considerations for spatial variability of CBP occurrence within different distribution systems are compared. For this purpose, a robust CBP database (i.e., high number of sampling locations selected according to system characteristics) corresponding to nine distribution systems was generated.The results demonstrate the high impact of the structure of the distribution system (e.g., presence of intermediary water infrastructures such as re-chlorination stations or reservoirs) and the spatial variability of CBPs in the assigned levels for exposure assessment. Recommendations for improving the exposure assessment to CBPs in epidemiological studies using available CBP data from water utilities are also presented.In recent decades, various epidemiological studies have been conducted to determine the relationship between chlorination by-products (CBPs) and different health outcomes (e.g., cancers and reproductive outcomes) [1-4]. Since trihalomethanes (THMs) and haloacetic acids (HAAs) are the most prevalent and documented CBP compounds in drinking water, they are generally considered as indicators of CBP exposure in epidemiological investigations.In epidemiological studies focusing on THMs and HAAs in drinking water and human health outcomes, exposure misclassification can occur through the assessment of population exposure to these compounds and especially in the estimation of their levels in residential tap water [5-7]. In fact, several parameters varying in time and space, such as water source characteristics, operational parameters during treatment and distribution system specificities, influence THM and HAA occurrence in distribution systems [8]. This temporal and spatial variability within drinking water systems could result in inaccuracies in the estimation o
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