Treatment of purified terephthalic acid wastewater using a bio-waste-adsorbent bagasse fly ash (BFA).
Purified terephthalic acid (PTA) plant of a petrochemical unit generates wastewater having high pollution load. Acid treatment of this wastewater reduces the chemical oxygen demand (COD) load by more than 50%, still leaving substantial COD load (>1500 mg/L) which should be removed. The present study reports on the use of a bio-waste-adsorbent bagasse fly ash (BFA) for the reduction of COD and other recalcitrant acids from this wastewater. The BFA showed basic character and was mesoporous with a BET specific surface area of 82.4 m2/g. Optimum conditions for the adsorptive treatment of acid-pretreated PTA wastewater were found to be as follows: initial pH (pHi) = 4, BFA dosage = 15 g/L, and contact time = 3 h. Adsorption treatment resulted in 58.2% removal of COD, 96.3% removal of terephthalic acid (TA), and 99.9% removal of benzoic acid (BA). TA and BA were removed from the pretreated PTA wastewater through precipitation and sedimentation of un-dissociated acid molecules inside the mesopores of the BFA. The results showed that the COD removed by the BFA followed pseudo-second-order kinetics. Equilibrium sorption data were best correlated by the Freundlich isotherm. The process of adsorptive removal of COD was found to be exothermic. The change in the Gibbs free energy was found to be negative, suggesting that the adsorption process is spontaneous and feasible for the treatment of PTA wastewater.
['Verma|Shilpi|S|', 'Prasad|Basheshwar|B|', 'Mishra|Indra Mani|IM|']
D000327:Adsorption D002482:Cellulose D060729:Coal Ash D006863:Hydrogen-Ion Concentration D007220:Industrial Waste D007700:Kinetics D010795:Phthalic Acids D013816:Thermodynamics D062065:Waste Water D014874:Water Pollutants, Chemical D018508:Water Purification
BFA Kinetics Isotherms Adsorption thermodynamics Petrochemical wastewater