Production and characterization of activated carbon from sunflower shell

Activated carbons are versatile adsorbents with high adsorbing power due to their surface properties and pore structures. Production can be made with many raw materials at laboratory scale. Commonly used activated carbon raw materials are lignite, wood, coal and coconut shell. Its high surface area, porous structure and low cost production have made it widely used as an adsorbent in the industry. For this reason, activated carbon is one of the commonly used materials in adsorption. One of the problems encountered in the industry is the pollution of heavy metals in water. It is of great importance for all living things to remove these highly toxic substances from water. For this reason, the aim of this study is to produce activated carbon from biomass and to remove Cr (VI), which is one of the toxic substances. In this study, activated carbon was produced from sunflower shell by chemical activation using ZnCl2 chemical agent. Activated carbon was produced in 1:1,2:1,3:1 and 4:1 impregnation ratios and temperatures of 400,500 and 600°C. The structural properties and functional groups of the produced activated carbons were determined by BET, FTIR, SEM, elemental, Boehm, pHZPC analyses. When the results in the BET analysis were examined, it was seen that the highest surface area (1501 m2/g) and pore volume were produced at 500°C at a 4:1 impregnation ratio. Activated carbon produced in the continuation of the study was used for Cr (VI) removal from aqueous solutions. Parameters such as pH, temperature, contact time, amount of adsorbent, which are the factors affecting adsorption, were investigated. According to the Langmuir and Freunlich isotherms, the adsorption equilibrium was analyzed and it was seen that the more suited the Freundlich isotherm. According to the kinetic model, it was observed that it followed pseudo-second-order kinetics. Finally, Adsorption thermodynamics (G°, H°, S°) were calculated and the results were evaluated.