Comparison of chlorine and sodium hypochlorite activity in the chlorination of structural fragments of humic substances in water using GC-MS

Abstract

The possibility of the formation of toxic products at the stage of drinking water disinfection as a result of interaction of disinfectants, such as chlorine and sodium hypochlorite, with model organic com pounds, structural fragments of natural humic substances is investigated using gas chromatography-mass spectrometry (GC-MS). Both qualitative and quantitative analysis of the products of water chlorination of dibenzoylmethane and cinnamic acid by chlorine and sodium hypochlorite was performed under the condi tions of an equimolar amount and five and fiftyfold excess of the chlorinating agent. Detailed diagrams of the transformation of organic compounds under the conditions simulating the process of natural water dis infection are drawn. The studies indicate that the use of chlorine leads to a greater variety and higher concen trations of chlorinated products compared to sodium hypochlorite.

Transformation of Organic Compounds during Water Chlorination/Bromination: Formation Pathways for Disinfection By-Products (A Review)

“…Lebedev and coauthors [ 84 , 85 ] studied the deep stages of aqueous chlorination of cinnamic acid with chlorine water and sodium hypochlorite. They found the high reactivity of the double bond, when less than 1% of the starting substance remained in the reaction mixture at a substrate/active chlorine ratio of 1/5 or higher.…”

“…For example, ortho -methoxybenzoic acid is easily chlorinated at the ring with the formation of ortho - and para -chloro derivatives as the main products [ 92 ]. Moreover, a 3-chlorophenyl derivative was the dominant reaction product upon the aqueous chlorination of dibenzoylmethane [ 85 ]; therefore, even the passivated ring entered into the electrophilic substitution reaction, especially, at a high dose of chlorinating agents (both chlorine water and sodium hypochlorite). Indeed, the reaction also actively proceeded at the methylene group of dibenzoylmethane; that is, active chlorine attacked the double bond of the enol form of the diketone [ 85 ].…”

“…Chlorine water results in a greater number products and higher degree of conversion, including the formation of chloroform. A conclusion on the possible contribution of radical processes leading to the formation of benzaldehyde, chlorobenzene, and 2-phenylacetic acid was also made [85]. UV filters are most common substances in swimming pool water.…”

Monitoring and Statistical Analysis of Formation of Organochlorine and Organobromine Compounds in Drinking Water of Different Water Intakes

“…The reason involves the fact that NaBr is a natural impurity in NaCl used in the production of industrial chlorinating reagents based on active chlorine, e.g., sodium hypochlorite. Since the reaction rate of hypobromic acid with aromatic species is significantly higher in comparison with hypochloric acid [41], even traces of bromine in technical chlorinating reagents may result in notable levels of the corresponding brominated DBPs [46,47].…”