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Phenol Removal From Coal Gasification Wastewater By Pervaporation

Posted on:2011-12-22Degree:MasterType:Thesis
Country:ChinaCandidate:X Q KouFull Text:PDF
GTID:2121330338480875Subject:Environmental Science and Engineering
Abstract/Summary:PDF Full Text Request
Pervaporation is a new type of membrane separation technology as one of the most active research areas in recent years. It was mainly used for separation of liquid mixtures, especially for the removal of a small amount of water from the organic solvents, or the volatile organic compounds from aqueous solution. Compared with the traditional separation technologies, pervaporation has many outstanding technical superiority such as energy-saving and atmospheric pressure operation and it shows a good application prospect for the removal of organic pollutants in wastewater treatment.In this subject, PDMS composite membrane was applied in pervaporation treatment of wastewater containing phenol of coal gasification and also various operation conditions on pervaporation performance impacts were investigated during the batch cycle operation process. In order to educe the optimum operating conditions, we mainly investigated the operating conditions on membrane separation performance which including the initial concentration of the coal gasification wastewater before and after pretreatment, system operating temperature, wastewater into liquid flow and the membrane reaction pool subarachnoid pressure.It was shown that waste water flux of phenol increased with the increasing of initial concentration of wastewater and it demonstrated a linear relationship at low concentrations. When the concentration of wastewater was less than 2500mg/L before pretreatment and less than 3000mg/L after pretreatment, penetration flux linear increased with the initial concentration. The relationship between the flux of phenol in wastewater with temperature conforms to the Arrhenius equation. With the increase of temperature, permeate flux increased monotonically. When the fluid flow in wastewater treatment increased, the flow of water on the surface of the membrane increased, thereby the flux increased. In addition, when the membrane reaction pool subarachnoid pressure was reduced, the equilibrium concentration of volatile phenol reduced below the membrane, membrane concentration difference of the phenol increased on both besides of the membrane, then the mass transfer impetus increased, so the flux increased.The optimisation operating conditions was obtained by pretreatment of sewage before and after from the experiment. The initial concentration of the pretreatment of wastewater was 2500mg/L, system operating temperature was 50℃, into liquid flow was 3.75L/h, reactor chamber pressure was 800Pa, the performance of pervaporation achieved to the optimal and the flux of phenol in wastewater could reach up to 20275mg/h·m2; pretreatment of wastewater suspended solids (SS) significantly decreased from 350mg/L to 114mg/L. The initial concentration in the wastewater is 3000 mg/L, the system operating temperature is 50℃, the liquid flow into the system is 4.50L/h, The reactor chamber pressure is 800 Pa , the pervaporation optimal performance, phenolic compounds in waste water infiltration through of up to 22700mg/h·m2.To study the intermittent cyclic process of mass transfer and the different flow conditions on pervaporation mass transfer process based on the PDMS which is on the structure flat composite membrane after pretreatment of coal gasification waste water . Sherwood formula using pervaporation process analysis the liquid phase mass transfer, mass transfer coefficients of liquid drawn, the series resistance combination of model and experimental data obtained membrane mass transfer coefficient. The experiment of the film mass transport resistance and membrane mass transfer resistance in the pervaporation system identified on the role of the controlling mass transfer resistance.
Keywords/Search Tags:pervaporation, phenolic wastewater, PDMS composite membrane, membrane mass transfer coefficient, boundary layer mass transfer coefficient
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