Utilização de coagulantes naturais obtidos de espécies de cactus para remoção de carga orgânica de efluentes têxteis

Abstract

The technique of coagulation / flocculation followed by sedimentation is used worldwide in the wastewater treatment process. The objective of this study was to investigate the performance of the coagulant activity of cactus species Opuntia ficus indica (OFI) and Cereus peruvianus (CP) in the coagulation / flocculation process. In the extraction of the active components of the species of cactus it was found that NaCl had compared with KCl and NaNO3 more efficient the extraction process is thus used in other assays. The effects of time and temperature of storage of cactus species have shown that the coagulation efficiency of cactus kept at room temperature did not change significantly during 4 days of stock. In assessing the cactus mucilage as a coagulant tests with real textile effluents were performed (laundry jeans - ELJ knitting and dyeing - ETM), it was used to extract cactus OFI for having presented the best results with turbidity simulated. The optimization processes with real effluent by response surface methodology (RSM) based on Box-Behnken experimental design is that the study variables were the dosage of FeCl3, pH and dosage of cactus as having answers to COD removal turbidity and for both effluents. The conditions were established as optimal for the effluent laundry jeans: FeCl3 dosage of 160 mg L-1, cactus dosage of 80 mg L-1 and pH 5.0, obtaining percentage reduction of COD and turbidity of 63.97% and 90.94% respectively. For ETM optimized conditions were: FeCl3 dosage of 640 mg L-1, cactus dosage 160 mg L-1 and pH 6.0, showing the percentage reduction of COD and turbidity of 88.32% and 95.73%, respectively.