Production of activated carbon from HNO₃-treated sawdust for methylene blue adsorption in solution

The report presents the process of preparing activated carbon (AC) from sawdust treated with HNO3 and evaluating the adsorption capacity of methylene blue (MB) of the material in solution. AC was synthesized under suitable conditions: carbonization at 600oC, then activated with HNO3 2M for 3 hours and further treated with NaOH. The structure and properties of the material were determined by modern methods such as XRD, SEM and FTIR. Analysis of the nitrogen adsorption – desorption process gave the specific surface area (BET) of 440.5433 m2/g. Investigation of the adsorption of activated carbon in the methylene blue concentration range from 5 - 35 ppm showed that 0.02g AC gave high adsorption efficiency when the MB concentration was below 20 ppm (H > 90%). Langmuir and Freundlich models were used to investigate the adsorption capacity, in which MB adsorption according to Langmuir isotherm model is more suitable than Frendlich model.