Removal of cationic dye from the aqueous solutions by using the natural clay of Maghnia (Algeria)

Abstract

The results obtained in this study showed that more than 80% of methylene blue (MB) was eliminated in the first five minutes with a neutral pH at 20°C and with the variable initial concentrations of MB between 5 and 30 mg/l in the presence of 1 g/l of clay. The clay of Maghnia flocculates in the presence of the MB in solution regardless of the strength of the pH of the medium. The optimal elimination of both MB (99%) and clay (98%) has been reached when mixing 120 mg/l of MB with 0.4–0.5 g/l of clay (FMC or SMC). The same result was obtained when mixing 20 mg/l of MB with 0.16–0.2 g/l of clay (FMC or SMC). Adding a suspension from the clay of Maghnia to the wastewater textile industry has proven effective. Second-order kinetic model represents well, this elimination with a coefficient of correlation R2 ranging between 0.9991 and 1.0. Freundlich, Temkin, and Dubinin–Radushkevich models showed that the temperature between 10 and 40°C does not have a great effect on this elimination. Thermodynamic parameters ΔG°, ΔH° and ΔS° indicated that the process is spontaneous with a weak energy.