Removal of methylene blue from aqueous solutions using polyaniline/graphene oxide or polyaniline/reduced graphene oxide composites

The polymeric nanocomposites polyaniline/graphene oxide (PANI/GO) and polyaniline/reduced graphene oxide (PANI/RGO) were synthesized for effective dye removal through the adsorption process. Synthesized composites were characterized by XRD, SEM, TEM and FTIR analyses. The sorption of methylene blue dye (MB) on the PANI/GO or (PANI/RGO) composites were studied as a function of contact time, concentration, temperature, adsorbent dosage and pH, and the results showed that MB sorption was dependent on pH value. The optimum concentration of the dye and the contact time for sorption of MB on PANI/GO or PANI/RGO was determined to be 270 min and 50 mg/L, respectively while the adsorbent dosage of PANI/GO and PANI/RGO were determined to be 0.4 and 0.3 g, respectively. At optimum conditions, the nature of the adsorption process have been investigated by kinetic and isotherm models. The results showed that the adsorption process followed the pseudo first-order kinetics this noticed from the higher value of correlation coefficient (R2 = 0.991) and was best suited to the Langmuir model. The maximum dye adsorption capacity of PANI/GO and PANI/RGO were estimated to be 14.2 and 19.2 mg g−1 respectively. From the results, it can be assured that the PANI/RGO is more effectively than PANI/GO for the removal of dye pollutants in water.