Study On Removal Of Four Kinds Of Trace Phthalate Esters In Water By Biological Activated Carbon Filter

Phthalic acid esters(PAEs) is trace environmental hormone pollutants generally exists in the source water and tap water, current water plant conventional treatment process for the removal ability of PAEs is limited, facing the increasing risk of detection of PAEs in drinking water, looking for PAEs feasible processing technology is imminent. Activated carbon is an excellent adsorbent material, Biological activated carbon filter, activated carbon as a carrier, combined with bio membrane treatment, because it is effective to remove organic pollutants in water and is widely used in drinking water treatment and wastewater. The present study on the adsorption of PAEs by activated carbon and the degradation of PAEs by biological activated carbon filter in drinking water is less, to establish the adsorption relationship between activated carbon and PAEs, studying the degradation ability of biological activated carbon filter for PAEs, plays an important role in ensuring the safety of the drinking water.This paper selects four typical PAEs(dimethyl phthalate(DMP), diethyl phthalate(DEP), dibutyl phthalate(DBP), diethylhexyl phthalate(DEHP)) as the research object. In the artificial simulated containing four PAEs pollutants in tap water, first to establish enrichment and detection method of four kinds of trace PAEs in water, and then the adsorption performance and the law of activated carbon on four kinds of PAEs were investigated by static adsorption. Through the operation of biological activated carbon filter reactor, the degradation of four kinds of PAEs on biological activated carbon filter was investigated, and providing a theoretical basis for the adsorption of activated carbon and the degradation of biological activated carbon filter to PAEs.Four trace amounts of PAEs were enriched and purified by solid-phase extraction, and then the samples were detected by gas chromatography-mass spectrometry. Eluting with 4ml ethyl acetate and 4mL dichloromethane, 86.1%~94.37% of PAEs can be recoveried by solid phase extraction. Heating procedure: The initial temperature is set to 50 degrees Celsius for keeping 2 minutes, then at per minute rate of 25 degrees Celsius to 150 degrees Celsius, the per minute rate of 10 degrees Celsius to 240 degrees Celsius for keeping 1 minutes, the per minute rate of 5 degrees to 280 degrees for keeping 3 minutes. Four PAEs can be separated and detected by Gas chromatography-mass spectrometry, and the linear correlation coefficient of peak area and concentration of four PAEs in the standard curve reached more than 0.999.Activated carbon have a good adsorption performance on the four kinds of PAEs, and the removal rate of the adsorption is DEHP>DBP>DMP>DEP. Under the conditions of isothermal adsorption at 25℃, the adsorption behavior of activated carbon on four kinds of PAEs can be described by Freundlich adsorption isotherm. When the sample solution pH value changing, the adsorption of DMP, DEP, DBP removal rate fluctuated and DEHP was not affected, the overall in neutral or slightly alkaline conditions the adsorption of four kinds of PAEs removal rate higher. Under the same experimental conditions, the content of four kinds of PAEs in the sample solution is lower, the higher the removal rate of PAEs on the adsorption; Increase the dosage of the adsorbent activated carbon, the adsorption rate of the four PAEs and the removal rate will be significantly increased.Biological activated carbon filter through the activated carbon adsorption and biodegradation synergies to achieve the removal of four kinds of PAEs, removal rate is different from the simple adsorption of activated carbon, the overall performance of DEP>DMP>DBP>DEHP. When the filter was operated stably, the biological degradation was dominant. Biofilm formation can be improve and ensure the continued removal ability of small molecular and easy to biodegradation of PAEs(DEP/DMP/DBP), and the removal rate of DEHP is not as better as the adsorption of activated carbon. When the biological activated carbon filter was activated and stable operation, the degradation ability of the four PAEs in water was positively correlated with the empty bed retention time, and was inversely related to the initial concentration of PAEs in the influent, When backwash expansion degree of biological activated carbon filter is 25%, Can not only effectively scrub the contamination of impurities, but also left enough the amount of microbes.The biological membrane and activated carbon filter can effectively remove the PAEs in drinking water, and open up a new way for the removal of environmental hormones.