Comparison of the efficiency of activated carbon and neutral polymeric adsorbent in removal of chromium complex dye from aqueous solutions

Abstract

The removal efficiency of chromium complex dye Lanasyn Navy M-DNL from aqueous solution using the activated carbon (AC) and the neutral polymeric adsorbent Macronet MN 200 (MN 200) has been investigated under various experimental conditions: initial dye concentration, pH and temperature. The effectiveness of MN 200 for the dye removal was found relatively higher than that of AC in both acidic and neutral solutions. Two theoretical models (pseudo-second-order-reaction and intraparticle diffusion) were used to describe the sorption kinetics, and to determine the constants of sorption rate ( k 2), intraparticle ( k i ) and film diffusion ( k s ). The both sorption systems dye-AC and dye-MN 200 follow the pseudo-second-order model with a higher k 2 value for dye-MN 200 in acidic media at 20 °C when compared with that of the dye-AC. With increase in the solution temperature from 20 to 40 °C the k 2 value for dye-AC indicate an increase in acidic media and decrease in alkaline media; whereas k 2 values for dye-MN 200 decrease in both acidic and neutral media. The rate of dye adsorption on both adsorbents is dependent on intraparticle and film diffusion proceeding simultaneously. The boundary layer effect is more pronounced in acidic solutions and with increase in temperature.