Treatment Of Atrazine By Micellar Enhanced Ultrafil Tration

Endocrine disrupting compounds (EDCs) have been shown to be present in the aquatic environment. The investigation shows that EDCs exits in the surface water, ground water and drinking water. EDCs may affect human and wildlife on their normal endocrines and lead to the descent of reproductive organism, developmental disorder. EDCs can pose a serious threat to the health and security of human and organisms, and have become a serious problem that influences human survival and development.At present, the removal of the Endocrine disrupting compounds has become one of the hottest topics in the word. However, EDCs are not removed effectively by using traditional water treatments. The application of membrane separation technology has been obtained rapid develop-ment in water treatments because of the effectiveness of membrane separation technology.The experimental retentions indicated that Nanofiltration(NF) and Reverse Osmosis(RO) process can remove EDCs effectively from water. The molecular weight cut-off (MWCO) of NF and RO are small, most of Endocrine disrupting compounds can be intercepted. But NF and RO craft always need high investment and high running cost. Micellar-enhanced ultrafiltration(MEUF) is a surfactant-based separation process. The development of MEUF has been demonstrated to be effective in the removal of low level of EDCs from water by using ultrafiltration process with relatively low investment and low running cost.In the paper, Atrazine was selected as the model pollutant which has typical endocrine disyupting effects. A analytical method based on solid phase extraction-high performance liquid chromatography-ultraviolet detector(SPE-HPLC-UVD) has been established for the determination of atrazine in water. Some parameters which may affect the recovery and chromatographic peak were investigated.The solubilizations of Cetylpyridiniumchloridemonohydrate (CPC) and Sodium-dodecyl sulfate(SDS) on atrazine were investigated. Application of solubilization and retention of atrazine by MEUF was studied in paper. Effects of operation, process parameters of solubilization and retention of atrazine by MEUF were investigated. The methods of cleaning polluted ultrafiltration membrane were also investigated. The most efficiency extraction of atrazine was achieved by using a solvent mixture of acetonitrile- high purity water(40:60, V/V) as the mobile phase, acetonitrile as the eluting solvent, the flow rate was 5ml/min, wavelength was 222nm.The recovery of atrazine was ranged from 97.2%～100.57%, the average relative standard deviations was 1.24%.The results indicated that both CPC and SDS have good solubilization capability for atrazine.Inorganic salt,β-cyclodextrin and nonionic surfactant were added into CPC and SDS. The optimal research showed that these methods do improve the solubilization of CPC and SDS on atrazine.Polysulfone membranes of 1000,5000,10000 dalton MWCO were used for MEUF.Effects of operation parameters(MWCO of membrane, influent surfactant concentration, operating pressure and pH) on the retention of atrazine, permeate flux, retention of atrazine, permeate surfactant concentration were investigated. Along with the increase of influent surfactant concentration, the retention of atrazine had an ascent trend, the permeate flux was reduced and the surfactant concentration of permeate was increased. CPC was used for forming micelles and using polysulfone membranes of 1000 dalton,5000 dalton,10000 dalton to remove atrazine, the highest retention were 81.9%,73.35%,65.60%. SDS was used for forming micelles and using polysulfone membranes of 5000 dalton to remove atrazine, the highest retention was 87.3%.The permeate flux and the surfactant concentration of permeate were increased with the increase of operating pressure.However, the retention of atrazine was decreased with the increase of operating pressure. Alkalinity and acidity of solution had little effect on the permeate flux, but had certain influences on the removal efficiency of atrazine, the retention increased at a low pH with CPC as surfactant, the retention decreased at a high pH with SDS as surfactant. pH of solution had little effect on the permeate flux.The way to optimize the craft of MEUF was studied to increase the retention of atrazine and decrease permeate surfactant concentrations.The inorganic salt-surfactant system can improve its performance significantly.The existence of Na2CO3 can increase the retention, decrease permeate CPC concentration. The existence of NaCl can increase the retention, decrease permeate SDS concentration.When APG(nonionic surfactant) was added to the anionic surfactant solution, the anionic surfactant concentration of permeate was reduced, the retention of atrazine is to be superior.When low concentrationβ-cyclodextrin was added to the surfactant solution, the retention of atrazine was increased. The phenomenon may be caused by formation of mixed micelle of surfactant withβ-cyclodextrin, then the mixed micelle had better solubility capacity than single surfactant.HPLC was used to analyse the removal process of atrazine in MEUF.The polluted UF membranes were investigated by using Scaning Electron Microscope(SEM). The membranes polluted by CPC and SDS were cleaned by sodium hypochlorite (NaClO) solution, the recovery rate of pure water permeation flux reached to 90.8% and 94.9%.