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Study of the adsorption of dyes from aqueous solutions onto novel graphene/chitosan composites (Bachelor thesis)

Τασσοπούλου, Μυρτώ/ Tassopoulou, Myrto

The present work is about the simultaneous adsorption of two dyes of different species from chitosan/graphene nanocomposite material. The novelty of the work is that the two dyes are in the same solution, which simulates the composition of real industrial waste. The aim is to find the optimal conditions for simultaneous adsorption, so that it can be done as efficiently as possible. The dyes that were studied are Methylene Blue (MB, cationic dye) and Reactive Black 5 (RB5, anionic dye). Graphene oxide (GO) was prepared by the improved Hummer's method, and three nanocomposites were produced: CS/GO, with GO ratios of 0.5, 1 and 2 %. The characterization of the materials CS/GO 0,5%, CS/GO 1% and CS/GO 2% was carried out using FTIR, SEM, XRD and BET techniques. Regarding the adsorption study, adsorption experiments were carried out for the effect of pH, contact time (kinetics), contaminant concentration in different temperatures (isotherms) and adsorbent mass. Each dye appears to have maximum removal rate under different optimum experimental conditions, so experiments were performed for each of them separately and for their mixture. For the mixture it was found that the optimum pH=5, teq= 360 min, the adsorption capacity increased with the increase of the temperature and optimum adsorbent mass was 0.05 g/L. It was found that at pH=5, there was 95% and 85% removal of MB and RB5, respectively. In conclusion, it appears that simultaneous adsorption of contaminants works, and thus further research around this area is worth developing for a more rapid and cost-effective adsorption