Détoxication des effluents d’industrie de textile par photocatalyse

Abstract

In Morocco the textile industry, representing 31% of all Moroccan industries, is accompanied by high water consumption and important wastewater discharges rejected without any treatment. The focus of this study was to characterize the effluent from the textile industry, to test separately the effect of UV light and TiO2 catalyst and to determine the optimum conditions (pH, concentration and reaction time) in photocatalytic treatment to reduce chemical oxygen demand (COD) and colour. The biodegradability of the effluent was also studied using a toxicity test before and after treatment. After 90 min of reaction time at pH 4 and with 1.5 g F' of TiO2 catalyst, the photocatalytic treatment reached a global removal rate of 53% for COD and 89% for discoloration of the effluent. The relation BOD5/COD increased from around 0 to 0.3. The effluent became accessible to a biological treatment. The toxicity was studied by the Daphnia magna test over 24 hours. The results have shown the important toxicity of these effluents, which are rich in organic matter and other chemical compounds. After treatment by photocatalytic oxidation, the CI50 24 increased from 3.8% to 22.8%. This reduction of toxicity is related to the reduction of COD (53%) and colour (89%). Photocatalytic treatment has been shown to have an environmental benefit and, in combination with a secondary biological treatment, can be important for a significant reduction in the pollution of textile effluents.

Treatment of real textile effluent containing indigo blue dye by hybrid system combining adsorption and membrane processes

“…Masmoudi et al (2015) studied the combination of coagulation-flocculationnanofiltration and found that this process exhibited a good ability to remove organic pollutants, total discoloration of textile effluents was observed with rejection of 98% of soluble organic matter and 99% of salts. Photocatalysis was applied by Gebrati et al (2010), their results showed a removal rate of 53.82% for chemical oxygen demand (COD) and 89% for discoloration of effluents. Özgün et al, 2022 presents a comparative study of microfiltration (MF) (0.2 µm and 0.05 µm), ultrafiltration (UF), ozonation (0.1, 0.2 g/L ozone), ultraviolet (UV) irradiation and titanium dioxide (TiO 2 ) (0.05, 0.15, 0.3, 0.5 g/L TiO 2 ) and zeolite adsorption (125, 250, 500 mL/min flow rates) as pre-treatment prior to nanofiltration (NF) and reverse osmosis (RO) for the treatment of real textile washing wastewater.…”

Impact of Powdered Activated Carbon and Anion Exchange Resin on Photocatalytic Treatment of Textile Wastewater

“…A less extent of research has been executed on PCO of real textile industry wastewaters, e.g. by Chun and Yizhong [23], Gebrati et al [24], Gümüş and Akbal [25], Hussein [26], and Pekakis et al [27]. In those experiments, specific energy consumption by UV lamps was between 270 and 4000 Wh/L.…”