Study on removal of m-phenylenediamine from aqueous solution by adsorption over granular activated carbon

Abstract

m-Phenylenediamine (MPD) is used for manufacture of thin film composite reverse osmosis (RO) membrane in polyamide thin film formation by interfacial polymerization. The used m- phenylenediamine solution has to be discarded as effluent. Granular activated carbon is found to be an efficient adsorbent for removal of m-phenylenediamine from aqueous solution. Brunauer-Emmett-Teller (BET) surface area of the granular activated carbon is 446 m²/g and micropore volume 0.15 cc/g. A systematic study of adsorption of m-phenylenediamine over granular activated carbon with different loading of adsorbent in given m-phenylenediamine solution concentration and different concentration of m-phenylenediamine solution in given adsorbent quantity has been carried out. Adsorption isotherms have been developed in each case. It is found that at 28% w/v concentration of adsorbent, the total MPD present in the 2% aqueous solution is adsorbed. It is found that adsorption of MPD over granular activated carbon follows Freundlich isotherm x/m = k c^1/n , where k =0.4576 and n = 4. Moreover, the study involves kinetics of adsorption of m-phenylene diamine over granular activated carbon at different temperatures and it is found that the kinetics of MPD adsorption over granular activated carbon follows Elovich Model. The kinetic study indicates that the optimum temperature of adsorption is 40°C as the MPD adsorption efficiency improves from 30 to 40°C and subsequently drops drastically for 45°C. The optimum temperature for adsorption has been found. It is found that granular activated carbon is an efficient adsorbent for removal of m-phenylenediamine from aqueous solution.