The HAAs Removal From Water And The Mechanism Studies With GAC Adsorption And AOPs

Haloacetic acids(HAAs) are of high carcinogenic risk as a major group of disinfection by-products(DBPs) in chlorinated drinking water. Before much work has been aimed at studying the removal of HAAs precursors by enhanced coagulation and alternative disinfectants. Besides the following filter being in abnormal conditions, further disposal of sludge and more flocculant consumption are needed for enhanced coagulation resulting in high metal ion concentration in drinking water. The substitutes for chlorin cost and pose the problems of themselves DBPs. Therefore the studies of the removal of HAAs formed in drinking water are very important.However the removal of HAAs formed in drinking water is short of study accumulation due to the limitation of HAAs analysis method. The thesis firstly aimed at the problem caused by the present HAAs analysis method as used in the processes of HAAs removal treatment, and studied a gas chromatography (GC) - mass spectrometry(MS) detection method for determining HAAs in drinking water using ultrapure water instead of MTBE as solvent for preparing stock standard solution, to avoid interference from MTBE and investigation spoiled by MTBE in the processes of HAAs removal treatment.Dichloroacetic acid(DCAA) and trichloroacetic acid(TCAA) posing main carcinogenic risk of DBPs in drinking water were selected as the objective pollutants.Aiming at the removal of HAAs the paper has two main object: 1,to study systematically the processes of static and dynamic adsorption of HAAs onto granular activated carbon(GAC) from water, and explore the influents of the pore structure properties and superficial chemistry characteristic on the adsorption ability of HAAs onto activated carbon. 2,to investigate the AOPs of HAAs so that the mend of HAAs removal is reached for the adsorption ability of DCAA inferior to that of TCAA .Through the static adsorption tests,dynamic adsorption test using rapid small-scale column test(RSSCT), it was found that GACs tested were significant different in the adsorption capacity with GAC-A being of the highest capacity, the adsorption ability of DCAA was inferior to that of TCAA, and the experiment results with isothermal adsorption and kinetics are in good agreement with Langmuir models for single component and multi-component system, the breakthrough point was advanced and water volume treated by per gram GAC decreased with decrease in empty bed contact time(EBCT) , and/or increase in the concentration of co-exist HAA and humus.