Tetracycline (TC) removal from wastewater with activated carbon (AC) obtained from waste grape marc: activated carbon characterization and adsorption mechanism

In this study, activated carbons were obtained from grape marc for tetracycline removal from wastewater. Activated carbons were obtained by subjecting them to pyrolysis at 300, 500, and 700 °C, respectively, and the effect of pyrolysis temperature on activated carbons was investigated. The physicochemical and surface properties of the activated carbons were evaluated by SEM, FTIR, XRD, elemental analysis, N2 adsorption/desorption isothermal, thermal gravimetric (TG) and derivative thermogravimetric (DTG), and BET surface area analysis. When the BET surface areas were examined, it was found that 4.25 m2/g for activated carbon was produced at 300 °C, 44.23 m2/g for activated carbon obtained at 500 °C and 44.23 m2/g at 700 °C, which showed that the BET surface areas increased with increasing pyrolysis temperatures. The pore volumes of the synthesized activated carbons were 0.0037 cm3/g, 0.023 cm3/g, and 0.305 cm3/g for pyrolysis temperatures of 300, 500, and 700 °C, respectively, while the average pore size was found to be 8.02 nm, 9.45 nm, and 10.29 nm, respectively. A better adsorption capacity was observed due to the decrease in oxygen-rich functional groups with increasing pyrolysis temperature. It was observed that the activated carbon obtained from grape skins can easily treat hazardous wastewater containing tetracycline due to its high carbon content and surface functional groups. It was also shown that the activated carbon synthesized in this study has a higher pore volume despite its low surface area compared to the studies in the literature. Thanks to the high pore volume and surface active groups, a successful tetracycline removal was achieved. Graphical Abstract: (Figure presented.) © The Author(s) 2024.