Research On The Effects And Mechanism Of Metal Ions On Chlorination Disinfection By-products

The control of Chlorination disinfection by-products of drinking water hasbeen a research hotspot in the field of water treatment. Research has shown thatmetal ion will have certain effects on the reactions derived by disinfectant andnatural organic matter (NOM) in the water in the process of liquid chlorinedisinfection, thus affecting the derivation and distribution rule of DBPs, as well asthe consuming and reducing course of disinfectant. In the water supply pipingsystem, the corrosion of pipeline, together with the sediments on the tube wall,including the dissolution of metal hydroxide and metal oxides,etc bring such metalelements as Magnesium, Calcium, Zinc, Aluminum, Ferrum and Manganese intoexistence, among which, the content of Calcium and Magnesium reaches dozens ofmilligram per litre, while the highest content of Ferrum reaches only ten milligramper litre, and that of Aluminum can reach ten milligram per litre. Meanwhile,industrial and agricultural emission of waste water in water environment leads tothe containment of plentiful metal compound in sediments at the river bottom,which can be discharged in the water. Moreover, the massive usage of coagulantcontaining Aluminum and Ferrum increases the content of metal ion and metaloxide in the water, thereby having negative effects on the quality of water supplyand drainage. Therefore, the study of the effects of metal ion during the process ofchlorination on formation rule of DBPs contributes to the comprehending thesecurity risk of metal ion in drinking water system, which has great significance onsafeguarding drinking water as well as controlling the derivation of its DBPs.Based on the traditional techniques of liquid chlorine disinfection, this paperwill adopt GC-EDC to analyze13kinds of volatile DBPs (TCM, TCNM, BDCM,DBCM, TBM, DCA, CH, DCAN, BCAN, DBAN, TCAN, DCP, TCP) and9kindsof non-volatile DBPs (MCAA, DCAA, TCAA, MBAA, BCAA, DBAA, BDCAA,CDBAA, TBAA) in detail. Besides, with the comparison between mental ions withinvariable valence and variable valence as well as the mechanism research of effectsderived by DBPs, this paper will also discuss the safety of drinking water in thechlorination process of metal ion.This study mainly choose common metal ions and water valence state of the metal ions with special properties. The research of metal ions in this paper coversMg2+、Ca2+、Zn2+、Ba2+、Al3+、Mn2+、Fe2+、Fe3+、Cu2+、Cu+etc. which may havecertain restrictive or simulative effect on DBPs. Through the study of metal ion,together with the filtration of NOM as chlorinated object, this paper will discuss thevariation of disinfection by-products THMs and HAAs, carry out an experiment toget datum, handle them, analyze the distributing transformation rules of all kinds ofDBPs and conduct on the affecting elements of the derivation of Chlorinationdisinfection by-products combining with the generation mechanism of DBPs.Through the study of divalent metal ions often, Mg2+, Ca2+generation ofchlorinated disinfection by-products have some effect. Ba2+and Zn2+on volatiledisinfection byproducts generated a certain role in promoting and Al3+had no effecton the volatile disinfection by-products, Ba2+, Zn2+, Al3+has a role in promotingnon-volatile disinfection by-products.Through the study of variable valence metal ions, metal ion with variablevalence has certain effect on both volatile and non-volatile DBPs, among which,Mn2+has the most effect on CH, As long as there is the presence of manganese ionconcentration of CH will from27μg/L increased to58μg/L, the concentration of theoriginal2-fold change. The Cu2+to promote maximum volatile disinfectionby-products, with increasing concentration of Cu2+, the concentration of TCM andCH respectively, by150μg/L and27μg/L becomes255μg/L and120μg/L.With the existence of Mn2+and Cu2+as well as the increase of pH, theproduction of DBPs keeps decreasing, which is probably the result ofdehalogenation. And the oxidation system derived by Mn2+and Cu2+, Within30minof cannot degrade parachlorobenzoic-acid (pCBA) and benzoic acid (BA), thus isconcluded that it is probably metal ion ‘s different valences and different formssuch as oxide form that degrade. The metal ions and chlorine oxidation systemformed in the oxidation of manganese ions and chlorine system formed afterpre-oxidation of water containing algae, the lowest chlorination experimentsconducted chlorination byproducts generated content.