Study of an organoclay for the sorption of dissolved organic compounds in the wastewaters from offshore platform operation

The goal of this research work was to find a sorbent able to selectively retain the harmful dissolved compounds in the wastewaters from offshore platform operation but not the carboxylic acids and to study the effects of the most important parameters on the sorption process. BTX compounds (benzene, toluene and p-xylene) and acetic acid were chosen as the representatives of the harmful compounds and carboxylic acids groups respectively since they are found in the highest concentrations. An organically modified clay was determined to be the most suitable sorbent, where performance was evaluated at different values of pH (3, 5 and 8), acetic acid concentration (0, 160 and 320 mg/l), salinity (0, 35 and 70 g/l) and temperature (20, 40 and 60°C). Results show that there is a sorption competition between BTX and acetic acid. Sorption of BTX compounds decreased with increasing initial acetic acid concentration and temperature, and increased proportionally with the salinity. Sorption of acetic acid, however, decreased with increasing pH, temperature and salinity.