Treatment of textile wastewater using the Co(II)/NaHCO3/H2O2 oxidation system
Francisco J. Ariza-Pineda, Iván F. Macías-Quiroga, Diego F. Hinojosa-Zambrano, Juan David Rivera, Diana M. Ocampo-Serna, Nancy R. Sanabria‐González
Abstract
Textile wastewater (TWW) is one of the most hazardous wastewaters for ecosystems when it is discharged directly into water streams without adequate treatment. Some organic pollutants, such as dyes in TWW, are considered refractory compounds that are difficult to degrade using conventional chemical and biological methods. The bicarbonate-activated peroxide (BAP) system is an advanced oxidation process (AOP) based on applying H 2 O 2 , which has been demonstrated to be a clean and efficient technology for dye degradation, with the advantage of operating under slightly alkaline pH conditions. In this study, response surface methodology (RSM) based on a central composite design (CCD) was used to optimize the degradation of TWW contaminated with the azo dye Acid Black 194 using the BAP system catalyzed with cobalt ions in solution (Co 2+ ). The analysis of variance (ANOVA) technique was applied to identify significant variables and their individual and interactive effects on the degradation of TWW. The optimum reagent concentrations for degrading TWW at 25 °C and with 45 μM Co 2+ were 787.61 and 183.34 mM for H 2 O 2 and NaHCO 3 , respectively. Under these conditions, complete decolorization (≥99.40), 32.20 % mineralization, and 52.02 % chemical oxygen demand removal were achieved. Additionally, the acute toxicity of textile wastewater before and after oxidation was evaluated with guppy fish ( Poecilia reticulata ), showing a total reduction in mortality after treatment with the Co 2+ –BAP system. The Co 2+ –BAP oxidation system is a potential method for textile wastewater treatment, which, in addition to achieving complete decolorization and partial mineralization, improves biodegradability and reduces the toxicity of the treated water.