CATALYTIC WET OXIDATION for ABATEMENT of TEXTILE DYES
Sustainable process-product development & green chemistry
Sustainable & Clean Technologies-I: Extraction & Remediation (T1-4P)
Keywords: catalytic wet oxidation, activated carbon, dyes, decolorization, mineralization
Synthetic dyes with great structural diversity are commonly found in textile industrial wastewaters. These effluents cannot be treated through conventional biological processes because of their poor biodegradability. Abatement of three dyes commonly found in textile wastewaters, such as Orange G (OG), Methylen Blue (MB) and Brilliant Green (BG) has been accomplished by Catalytic Wet Oxidation (CWO). CWO has been studied in a three phase Fixed Bed Reactor using a commercial activated carbon, Industrial React FE01606A, as catalyst. Runs were carried out at 160 ºC of temperature and 16 bar of oxygen pressure. The initial pollutant concentration was 1000 mg/L. The pollutant conversion was quantified by HPLC using a Diode Array detector, and the remaining total organic content (TOC) was measured. The toxicity of the liquid samples at the reactor outlet was determined by means of a bioassay following the standard Microtox test procedure (ISO 11348-3, 1998).
The catalyst showed high catalytic activity in dye conversion and colour removal. Catalyst stability was good during the time on stream tested (200 h). TOC conversion reached asymptotical values of 40 % in OG and 60 % in MB and BG. Toxic intermediates are obtained when CWO of MB is carried out, while non toxic effluents are obtained for CWO of OG. A maximum in the toxicity of the CWO of BG is achieved due to nitrogen containing aromatic intermediates.
Presented Monday 17, 13:30 to 15:00, in session Sustainable & Clean technologies - I: Extraction-Remediation (T1-4P).
