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Abidi N.,University of Carthage | Abidi N.,CNRS Hydrology and Geochemistry Laboratory of Strasbourg | Errais E.,University of Carthage | Duplay J.,CNRS Hydrology and Geochemistry Laboratory of Strasbourg | And 7 more authors.
Journal of Cleaner Production | Year: 2014

Treatment of dye-containing effluents is a significant challenge because dyes are toxic and pose a threat to the environment. Recent studies have shown that natural clay is able to efficiently remove colour from effluents that contain dyes and various additives. The objective of this study is to investigate the combined effects of dyes, salts and auxiliary chemicals used in the dyeing process, on the adsorption process onto natural clay for the treatment of dye-containing effluents. Batch adsorption experiments were performed using real and synthetic effluents containing dyes (Reactive Red 120, Reactive Orange 84 and Reactive Blue 160), and natural clays (Fouchana and Tabarka). The results show that both of the natural clays are efficient in treating real effluents. Fouchana clay shows a higher efficiency than Tabarka clay in the discolouration of the most colour loaded solution. The added chemical of enzymatic nature (Catalase) facilitates the adsorption of anionic dyes onto clay, likely by electrostatic attraction interaction with the SO3 - groups in the dye, followed by the adsorption onto the clays, of the dye-enzyme system. The mixture of all additives, enhances the adsorption of dyes on the clays, and does not act as a barrier to the decolouration process. Therefore, clays which are inexpensive and effective adsorbents may be promising alternatives for the treatment of the textile dyeing effluents. © 2014 Elsevier Ltd.

Ellouze E.,University of Sfax | Souissi S.,University of Sfax | Jrad A.,Center International Of Lenvironnement Of Tunis Citet | Ben Amar R.,University of Sfax | Ben Salah A.,University of Sfax
Desalination and Water Treatment | Year: 2010

In this paper experimental results obtained from the treatment by different membrane based processes, namely, microfiltration (MF), nanofiltration (NF) and reverse osmosis (RO) of Sitex industry waste water pretreated by biological activated sludge are presented and compared. The results obtained from direct NF performed at different transmembrane pressures (8 < TMP < 14 bar) and at a temperature (T = 25 °C) show that the permeate flux decreased from initial value of 19 to 9 l/h · m2 for a volume reduction factor (VRF) of 4 and that the osmotic pressure φ = 4 bar. A high quality of treated effluent in term of colour removal and desalination was obtained for a VRF of 2: salinity retention rate (R) 57% and decolourization almost 100% at pressure of 12 bar. While, the permeate flux obtained using the combination MF/RO at a different pressures 10 < TMP < 24 bar decreased from initial value of 35 to 20l/h · m2 for a VRF of 7 indicating an important fouling. The optimum salinity and colour retention rate were 86% and 100%, respectively obtained at a VRF of 2. © 2010 Desalination Publications. All rights reserved.

Ellouze E.,University of Sfax | Ellouze D.,University of Sfax | Jrad A.,Center International Of Lenvironnement Of Tunis Citet | Ben Amar R.,University of Sfax
Desalination and Water Treatment | Year: 2011

Industrial textile generates large volumes of effluents which are heavily loaded with pollutants, turbidity and are highly concentrated in salts and color. A significant improvement in effluent quality is required before it is discharged into the environment. In the present work, performances of a combined process using chemical coagulation, ultrafiltration and nanofiltration were investigated in treating synthetic textile wastewater containing reactive dyes (Blue S-GLD 150 dyes) and different salt concentration. The efficiency of the combined process was evaluated in terms of effluent decolourization and turbidity removal. Experimental results showed that the optimal dose of coagulant using aluminium sulphate was 1 g/L obtained at pH = 7. The decrease of the effluent salinity improved the treated water quality by increasing the removal of color and turbidity. To explain the effect of the salinity on the optimal coagulant dose, the zeta potential was used as a control parameter. When ultrafiltration (UF) or nanofiltration (NF) were used in post treatment to coagulation-flocculation, the stabilized permeate flux was higher for UF. It remained constant until a volumetric reduction factor (VRF) reaching 4 for NF and 6 for UF at 25 L/h.m2 and 122 L/h.m2 respectively. The retention of color and salt were higher for NF than for UF. These results were similar for real and model effluent. © 2011 Desalination Publications. All rights reserved.

Tahri N.,University of Sfax | Masmoudi G.,University of Sfax | Ellouze E.,University of Sfax | Jrad A.,Center International Of Lenvironnement Of Tunis Citet | And 2 more authors.
Journal of Cleaner Production | Year: 2012

Dye baths of low volume compared to the volume of water used in other processing operations generate significant pollution and contaminate other wastewaters that are generally less loaded with pollutants. The aim of the present work is to treat different combination of selected dyeing cycle baths of using the combination of Microfiltration (MF) with Nanofiltration (NF) in order to reuse the treated water in the dyeing process. The characterization of the effluents coming from the different dyeing steps shows that the cotton preparation and dyeing baths are the most polluted due to the presence of dye and to high salinity content. The performances of the combination MF/NF to treat two types of effluents (Effluent 1 which is a mixture of the more polluted baths and effluent 2 which is a mixture of all baths used during the dyeing cycle) were studied. The pretreatment by MF leads to a 50% of pollutant retention except for salts which do not exceed 13%. The addition of NF leads to a high quality of treated effluent with retention of salt, color, suspended matter and COD respectively of 47-52%, 100%, 99.9% and 73-85% depending of the effluent load. The use of MF as a pretreatment prior to NF improves the treatment effectiveness by increasing the operating time and the permeate flux. NF permeate quality was satisfactory enough to be reused in reactive dyeing baths. © 2012 Elsevier Ltd. All rights reserved.

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