Antimony removal from the polyethylene terephthalate manufacture wastewater

Abstract

In this study, antimony removal by coagulation from polyethylene terephthalate resin production wastewater of „Orion Global PET“ factory in Klaipėda city was investigated, with regard to the dependence of coagulant type and dosage, pH and presence of organics. FeCl₃ ∙6H₂O, FeSO₄ ∙7H₂O, AlCl₃∙6H₂O and TiCl₄ salts were used as coagulants. Ti(IV) and Fe(III) revealed oneself to be the most effective coagulants. Antimony removal effectiveness is moderate and low using FeSO₄ ∙7H₂O and AlCl₃∙6H₂O coagulants, respectively. The addition of 10 mg dm^-3 Ti(IV) and 30 mg dm^-3 Fe(III) reduces by ~98% of the Sb, when the initial amount of Sb in wastewater is about 1200 mkg/l. The action of Fe(III) is practically independent in the pH range 4-9, and that of Ti(IV) slightly decreases in the same pH interval. The Sb amount in wastewater can be reduced to 13-20 mkg dm^-3, while the initial Sb concentration is 1200 mkg dm^-3. The presence of organic compounds in wastewater determines the reduction of Sb removal by coagulation.