The synthesis of active carbon from chemical activated waste tea stem with phosphoric acid

In this study, the production and characterization of activated carbon from tea stem waste, which is the agricultural waste belonging to Rize region, was investigated. It is aimed to produce low cost activated carbons with high surface area ( >1200 m2/g). For this purpose, in addition to classical methods, activation method including demineralization pre-treatment was proposed. To determine the optimum production conditions by chemical activation method, the effect of temperature (300, 400, 500, 600, 700 ve 800 ºC), the carbonization time (60, 120, 180, 240 min) and the impregnation rate (activation agent: sample, 1:1; 2:1; 3:1; 4:1; 5:1; 6:1) was investigated by applying two different activation methods. Microporosity and mesoporosity values were calculated by using iodine number and methylene blue number analysis, respectively. Following this steps, surface functional groups were determined by Boehm titration and FTIR analysis of raw material and activated carbon. As a result of these methods, it was determined that product yield, BET surface area and porosity values decreased with increasing carbonization temperature and time. The values obtained from the methlyene blue number and iodine number analysis showed that the activated carbons were mesoporous and predominantly microporous and these results are consistent with the BET surface area. The porosity of activated carbon was determined by SEM analysis. FTIR analysis and Boehm analysis have shown that activated carbons can be used as an effective adsorbent in adsorption studies due to their superior surface properties. Thus, it can be concluded that tea stem waste can be used as raw material in activated carbon production and optimum values of activated carbons produced by demineralization pre-treatment can be reached at lower temperaature.