RESUMO
The removal of toxic compounds (azo dyes) from dyeing wastewater was investigated by an environmentally friendly activated carbon produced from solid waste generated in the tannery process, the cattle hair (CHW), activated with H3PO4 (AC-CHW), suggesting a life cycle extension for this material from leather processing. Preliminary tests with aqueous solutions containing Acid Brown 414 (AB-414) and Acid Orange 142 (AO-142) removed 71.06% and 73.05%, respectively. The activated carbon was characterized by zeta potential (ZP), functional groups (FTIR), elemental composition, sorbent specific surface area, and pore size distribution (BET/BJH). The specific surface area showed low values when compared to commercial activated carbon, but average pore diameter was higher, which facilitates the adsorption of larger and complex molecules, such as those present in real wastewaters. Through SEM and FTIR, the presence of the toxic compounds studied in the AC-CHW after sorption process was observed, where the results indicated that the functional groups of -CH=CH- participated in the removal process for these compounds. The removal efficiency obtained with AC-CHW was 51.94% and 49.73% for the dyeing wastewater containing AB-414 and AO-142, respectively. The obtained results open a promising via to use AC-CHW as efficient eco-friendly sorbent for the treatment of leather wastewater.
Assuntos
Carvão Vegetal/análise , Curtume , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Adsorção , Compostos Azo , Carbono , Carvão Vegetal/química , Corantes , Águas Residuárias/químicaRESUMO
Physical and thermal treatment was used to inactivate Trametes sp. SC-10 fungus. The resulting biomass was named BTV, characterized by analytical techniques such as SEM, EDX, FTIR, BET, and Barrett-Joyner-Halenda (BJH) model. pH, kinetic, and equilibrium adsorption studies with the Acid Blue 161 (AB-161) dye were investigated at 303.15 K. The kinetics of the biosorption process were examined at 600.00 and 1300 mg L-1, using pseudo-first-order, pseudo-second-order, and Avrami fractional-order models. The maximum biosorption capacity of BTV for AB-161 dye was 221.6 mg g-1. Considering the biosorption data and the functional groups of BTV, it can be inferred that the sorption mechanism of AB-161 is regulated by electrostatic interactions between ionized dye molecules and negative charges on BTV in an aqueous solution. Finally, the BTV was tested with a simulated effluent with 89.47% efficiency, presenting the BTV as a biosorbent for real effluents polluted with dyes.