Experimental Research On Removal Of Amine N-dbps By Modified Activated Carbpn In Drinking Water

As an important technology in water treatment plant, disinfection can not only kill bacteria, but also generate disinfection byproducts(DBPs). And, the toxicity and carcinogenicity of nitrogen-based disinfection by-products(N-DBPs) are stronger than the carbon-based disinfection by-products(C-DBPs). Therefore, the study the removal of N-DBPs in drinking water is of great significance. By activated carbon and zeolite were modified, screened out of the best materials that adsorped nitroso diethylamine(NDEA) and dichloro acetamide(DCAcAm) adsorption in respective. Then, studied the adsorption properties modified materials, to shallow investigate the adsorption mechanism.Activated carbon and zeolite were modified in different concentrations of ferric sulfate, calcined at different temperatures and times. The results showed that the adsorption properties of activated carbon to DCAcAm NDEA are superior the adsorption properties of zeolites as a whole. By orthogonal experiments, activated carbon was modified while ferric sulfate was 0.3 mol/L, calcination temperature 500℃, calcination time 3h, the adsorption of NDEA was optimal; activated carbon was modified while ferric sulfate was 0.5mol/L, calcination temperature 400 ℃, roasting time 2h, the adsorption of DCAcAm was best.Studied the adsorption properties of PAC-1 to NDEA. The results showed that, PAC-1 had high adsorption capacity to NDEA compared with the AC, and the removal rate of NDEA improved 1.4 times. From the single factor analysis and orthogonal adsorption experiments, could obtain the best adsorption conditions for NDEA: the reaction time was 30 min, PAC-1 dosage of 4.0 g/L, pH 8.0, removal rate of 10 mg/L of NDEA solution was 92.1%. By adsorption kinetics study, the adsorption of NDEA followed pseudo-second kinetic equation,contained the physical adsorption and chemical adsorption. Adsorption process was controlled by the combined action of diffusion and mass diffusion. The adsorption isotherm could be described by the Langmuir equation. Adsorption process belonged to chemical adsorption monomolecular layer, was a spontaneous process and endothermic reactions.Studied the adsorption properties of PAC-2 to DCAcAm. The results showed that, PAC-2 had high adsorption capacity to DCAcAm compared with the AC, and the removal rate of DCAcAm improved 1.67 times. From the single factor analysis and orthogonal adsorption experiments, could obtain the best adsorption conditions for DCAcAm: the reaction time was 200 min, PAC-2 dosage of 4.0 g/L, pH 3.0, removal rate of 10 mg/L of DCAcAm solution was 97.1%. By adsorption kinetics study, the adsorption of DCAcAm followed pseudo-second kinetic equation,contained the physical adsorption and chemical adsorption. Adsorption process was controlled by the combined action of diffusion and mass diffusion. The adsorption isotherm could be described by the Langmuir equation. Adsorption process was a spontaneous process and endothermic reactions. The higher the temperature is, the more beneficial to adsorption is.Studied the adsorption properties of PAC-1 and PAC-2 to mixed liquid. The results showed that, the removal rate of NDEA are high while DCAcAm was hardly removed. This shows that there is a strong competition between the NDEA and DCAcAm, and the competitiveness of NDEA was significantly higher than DCAcAm.The properties of PAC-1 and PAC-2 were characterized by specific surface area analysis, Scanning Electron Microscopy and X-ray Diffraction. The results show that the surface morphology of the modified activated carbon has changed, pore structure significantly enhanced, specific surface area and pore volume were increased. The adsorption properties of PAC-1 to NDEA and PAC-2 to DCAcAm enhanced respectively.