Production of porous reduced graphene/activated carbon (rGO/AC) composite aerogel and dye adsorption study from aqueous solutions

Industrial textile and dye factory wastewater causes environmental pollution with its large amounts of cationic dye content. Therefore, in this thesis study, reduced graphene/activated carbon doped PVDF aerogel (rGO/AC/PVDF) was prepared. In this study, the adsorbent material was preferred as aerogel due to its lightness and porous structure. The aerogel was characterized by Fourier Transform Infrared Spectrometry (FTIR). The pore size of the aerogel was determined by BET (Brunauer-Emmett-Teller) analysis. The prepared adsorbents were used to remove methylene blue (MB) from aqueous solutions by the adsorption process. Additionally, the effects of varying parameters such as aerogel adsorbent dose, contact time, pH, temperature and initial dye concentration on methylene blue adsorption were examined. Considering the adsorption of methylene blue in wastewater without pH adjustment, all adsorption studies were carried out at pH 7 in this study. Under optimum conditions at pH 7, methylene blue removal increased with the amount of adsorbent. For an initial MB concentration of 33 mg/L, 84,135% adsorption efficiency was obtained under optimum conditions (10 g/L rGO/AC/PVDF aerogel, 200 rpm, 120 minutes, 25oC). In the study, Langmuir, Freundlich and Temkin models were chosen to explain MB adsorption of aerogel, and equilibrium data were applied to isotherm models to obtain information about the theoretical capacity, energy and type of adsorption of the adsorbent. It was determined that the adsorption equilibrium data were more suitable for the Langmuir isotherm. With the Langmuir isotherm, the maximum adsorption capacity was determined as 2.73 mg.g-1 and the experimental maximum adsorption capacity was determined as 2.568 mg.g-1. Adsorption kinetics was investigated in accordance with the pseudo-first-order (PFO) and pseudo-second-order (PSO) rate equations, and it was determined that the adsorption rate was more suitable for the pseudo-second-order model.