Due to the toxicity of phenol pollutants in aqueous media, different methods are being used to separate this pollutant from water. One of the methods used for this purpose is pervaporation membrane process. Since the membrane is the most important key factor in determining the performance of membrane processes, the aim of this research was to make a ceramic/polymer composite membrane by using phenol-formaldehyde resin and eva‎luation of its performance in the pervaporation process. For this purpose, a tubular ceramic support was first made by the gel casting method, and then it was coated with a solution containing novolac resin. In the process of making the ceramic support, the optimal amount of dispersing agent for a 50wt.% alumina suspension by weight was determined to be 0.34 grams of Darvan per 100 grams of dry alumina powder. Also, the optimal amount of the gelling agent and its effect on the porosity percentage of the piece were investigated. For the amount of 8wt.% of gelatin respect to the amount of final water used, the percentage of porosity was obtained at about 51%. Also, the liquid desiccant method was used for the initial drying of the ceramic supports and some experiments were conducted to control the drying rate of the supports to obtain a part without any defects. Considering that PEG has hydrophilic functional groups such as hydroxyl group, the effect of factors such as the molecular weight of polyethylene glycol and its concentration that determine the amount and effects of hydroxyl groups on drying speed was investigated. As a result, the optimal concentration of desiccant solution of PEG 4000 in ethanol was found to be 0.1wt.%. In the next step, for modification of the surface by dip-coating method, the effects of influencing factors such as the concentration of the polymer solution, the dipping time in the solution, and inserting and withdrawal rate of the substrate were investigated. Results showed that the optimal values to obtain a uniform and dense layer were the dipping time is 60 seconds and the inserting/withdrawal rate of 5 mm/min by using a 60 wt.% novolac solution in ethanol. After making the optimized membrane, field emission scanning electron microscopy (FESEM), X-ray energy dispersive spectroscopy (EDS) and water contact angle (WCA) analyses were employed for further characterization of the membrane. The results of the FESEM analysis confirmed the formation of a dense layer on the ceramic support. Also, EDS and WCA results revealed the satisfactory quality of the coating process by showing the surface elements and changing the contact angle from 22 to 83 degree. Finally, water separation tests from phenol in the pervaporation process were performed to eva‎luate the membrane performance, and, the effects of feed concentration and temperature were investigated. Based on the results, the membrane had the highest flux and separation factor at the lowest concentration value (1000 ppm) and the highest temperature (75 °C). At these conditions, the parameters of permeation flux, separation factor, and pervaporation separation index were equal to 12 kg/m2.h, 29.89, and 346.68 kg/m2.h, respectively.

احمد محب

مرتضي صادقي , سهيل ضرغامي