Removal of Organic Matter and Etodolac from Pharmaceutical Industry Wastewater by PAC Adsorption

Abstract

The removal of organic matter and etodolac (an anti-inflammatory pharmaceutical) from a real process wastewater by using powdered activated carbon (PAC) adsorption before and after Fenton oxidation has been studied. The wastewater sample is collected from the final stage of chemical synthesis of a pharmaceutical (etodolac). Fenton oxidation resulted with decrease in chemical oxygen demand (84% removal) and etodolac concentration was reduced to 0.7 mg L-1. Optimum adsorption equilibrium conditions were found as t = 16 hours, and m = 10 g L-1. The Freundlich model showed the best fit for the adsorption of both wastewater with R-2 values of 0.89 and 0.99. Lower pseudo-second-order rate constant (k(2)) (0.067 < 2.62) obtained from the adsorption of raw wastewater with higher organic matter concentration confirms the chemisorption of the adsorbates onto the PAC. Pore surface mass diffusion with R-2 value of 0.92 was found as rate-controlling step for adsorption process with Fenton pre-treated wastewater.