Sumrit Mopoung, Rinlaphat Thanakulwaranon,
Volume 21, Issue 0 (IN PRESS 2024)
Abstract
Activated charcoals were prepared by activation with 600 W microwave irradiation in combination with pretreatments of tamarind wood derived charcoal in boiling mixtures with NaOH (1 g : 0 g - 1 g: 0.12 g). The samples were characterized by FTIR, XRD, SEM-EDS, and BET, and used for catalytic nitrite c oxidation under air atmosphere in the absence of light at 30°C, pH 6.5, and 120 rpm shanking for improved efficiency. The results show that the percent yields of tamarind wood derived activated charcoals (ACCs) were 88.51% - 94.66 %. The main carbonate compounds of ACCs are present in the materials after activation. Na+ ions and water molecules could be inserted into the graphitic layers during pretreatment and efficiently effected surface cracking of ACCs by 600 W microwave irradiation. The surface cracklings and porosities of ACCs increased with increasing concentration of NaOH from 1 M to 3 M with optimum at 2 M NaOH. The final products are mesopore materials containing macro and meso hole channels. It was found that the nitrite conversions exhibit high reaction rates and are completed within 20 min. The reactions proceed via catalytic oxidations and their rates increase with increasing concentrations of NaOH activation, while nitrite conversions via the disproportionation reaction were inhibited.
Sumrit Mopoung, Khachidapron Seeoon,
Volume 22, Issue 2 (JUNE 2025)
Abstract
Activated carbon preparation from tamarind wood derived charcoal by microwave-assisted sodium chloride activation was studied to investigate the effects of 0-5 wt.% NaCl and 450-850 W microwave heating power. The properties of the derived products were analyzed by FTIR, XRD, SEM-EDS, and BET. Methylene blue adsorption by the activated carbon products was also studied to evaluate the contract time, pH, methylene blue concentration, and adsorption isotherms. The study’s results showed that the percent yields (77.42-92.52%) of the fabricated activated carbons decrease with increasing wt.% of NaCl and MP. On the other hand, the contents of disordered graphitic carbon, carbonate, basic surface functional groups, and mesopores increased. However, 3 wt.% NaCl and 600 W microwave irradiation power were identified as appropriate conditions for activation, which created the micro-mesopore (pore size range 1.59 -14.76 nm) on the surface of the derived activated carbon products. Optimal values of equilibrium time and pH for methylene blue adsorption are 60 minutes and 8, respectively. The results of methylene blue concentrations were fitted to the Langmuir isotherm indicating 33.33 mg/g as the maximum methylene blue adsorption capacity.
