Treatment of complex aqueous solutions by the coupling of ultrafiltration and adsorption onto activated carbon cloth

The aim of this work was to estimate the efficiency of coupling the processes of ultrafiltration and adsorption onto an activated carbon cloth in order to treat complex aqueous solutions containing both organic micropollutants and macromolecules. First, the effectiveness of each treatment process was studied separately in batch reactors for microorganics, like phenol or atrazine, and macromolecules like humic substances. The activated carbon cloth displayed higher adsorption capacities for microorganics than granular activated carbon, from 45 mg g(-1) for phenol up to 370 mg g(-1) for atrazine, whereas they were not efficient at adsorbing humic substances. Conversely, as many as 80% of these macromolecules were removed by an ultrafiltration membrane with a 10 000 D molecular weight cut-off. Secondly, the coupling was tested directly using a surface water with an initial total organic carbon of 20 mg l(-1) and around 30 mg l(-1) of suspended solids. At first, batch experiments showed that the ultrafiltration step increased the activated carbon cloth performance, and the comparison of several activated carbon cloths of different properties showed that the total organic carbon removal was dependent on the adsorbent pore-size distribution. Then, continuous flow reactor experiments were carried out using the surface water loaded with atrazine. A coagulation-flocculation step was tested as a pre-treatment. The specific adsorption of micropollutants onto the activated carbon cloth was displayed: the pre-treatment improved the permeate quality (lower values of total organic carbon), whereas it had a negligible impact on atrazine adsorption.