Removal of anionic dye from textile industries' effluents by using Tunisian clays as adsorbents. Zeta potential and streaming-induced potential measurements

In the present work, we have investigated the adsorption capacities of natural raw clays originated from Tunisia, such as those from Tabarka (a mixture of kaolinite and illite) and from Fouchana (a mixture of smectite, kaolinite, and illite), a standard kaolinite (KGa-2), and a palygorskite (PFI-1) for the removal of a reactive red dye (RR 120) usually found in textile industry effluents. Thus, batch adsorption experiments were performed and were tuned by varying different parameters such as adsorption contact time, aqueous phase pH, ionic strength, and initial dye concentration. In addition, zeta potential measurements allowed the determination of the electrical charge and of the dye behavior at the clay -water interface. Despite the fact that palygorskite has higher porosity and specific surface values, the amount of dye adsorbed on this clay is low in comparison to that of the other solid samples, regardless of the values of pH and ionic strength of the aqueous phase. On the other hand, a higher amount of adsorbed dye was observed on KGa-2, having the lowest specific surface area value. This sample, in comparison to smectite and fibrous clays, was found to be more efficient in the removal the anionic dye, and thus it can be used as an adsorbent for the treatment of effluents in the textile industry. (C) 2018 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.