title: COD removal and toxicity decrease from tannery wastewater by zinc oxide-assisted photocatalysis: a case study.
abstract: This work reports the optimization of degradation conditions and toxicity decrease in the tannery wastewater, collected in the retanning and dyeing steps. This effluent was filtered, diluted in a 1:200 proportion, and investigated as a case study on a bench scale by heterogeneous photocatalysis. These conditions were attained when the suspension, containing 1 g L-1 of ZnO and effluent, was irradiated for 4h at pH 8.0 and 30 degrees C. Physico-chemical parameters such as chemical oxygen demand (COD) decreased from 15,023 to 350 mg O2 L-1; fifth-day biochemical oxygen demand (BODs) from 4374 to 10 mg O2 L-1; total solids from 28,500 to 188 mg L-1; total organic carbon (TOC) from 4685 to 4.93 mg L-1, and turbidity from 331 to 1.15NTU after 4h of irradiation. The LC50 increase from 14.90% to 56.82% in the lethality assay of Artemia salina L. microcrustacean as well as the dissolved oxygen of 6.45mg L-1 indicated efficiency in this treatment.
authors: Maria Claudia
authors: MC
authors: Hasegawa
authors: Juliana Feijó de Souza
authors: JF
authors: Daniel
authors: Keiko
authors: K
authors: Takashima
authors: Gisselma A
authors: GA
authors: Batista
authors: Sandra M C P
authors: SM
authors: da Silva
mesh_terms: D000818:Animals; D001156:Artemia; D057919:Biological Oxygen Demand Analysis; D007220:Industrial Waste; D010782:Photolysis; D013633:Tanning; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000633:toxicity; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D007220:Industrial Waste; D062065:Wastewater; D015034:Zinc Oxide