Adsorptive separation and recovery of organics from PHBA and SA plant effluents

Adsorption as a process for the removal and recovery of organics from actual industrial effluents has been studied. The wastewater was obtained from Salicylic acid (SA) and p-hydroxy benzoic acid (PHBA) manufacturing units. The major constituents of the wastewater were Phenol, PHBA, SA and sodium sulphate. Equilibrium adsorption studies were carried out for four different polymeric resins, Amberlite XAD-2, -4, -7 and INDION 1014 MN-2 (IMN-2) having different surface areas, to find out the resin with maximum equilibrium loading capacity. Since IMN-2 gave the highest capacity it was used for further studies. Effect of presence of salt was also studied since the effluent contained a substantial amount of it. An attempt was made to correlate multi-solute equilibrium data using extended Langmuir model with a modification to account for salting out effect. The discrepancies in experimental and predicted values were attributed to the possible hydrogen bonding ability among the solutes. Column studies were also carried out to investigate the breakthrough behavior at two different flow rates to investigate the column capacity. LUB values were calculated to find out column efficiency. Regeneration was accomplished by four to five bed volumes of acetone. Quantitative recoveries of organics were obtained from the column operations for SA and PHBA plant effluents. (C) 2003 Elsevier B.V. All rights reserved.