Amphol Aworn

King Mongkut's University of Technology Thonburi, Dhonburi, Bangkok, Thailand

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Publications (4)9.68 Total impact

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    ABSTRACT: Activated carbon was produced from corncob using CO2 for the activation process. This research investigated the effect of the remaining volatile matter in corncob char combined with CO2 activation to improve the pore properties of corncob activated carbon. The pore structure was characterized using the Brunauer–Emmett–Teller (BET) surface area test, total pore volume, mesopore volume, micropore volume and average pore diameter. This study discovered that the amount of volatile matter in corncob char is about 17–25% and results in a BET surface area range of 919–986 m2 g−1 by the CO2 activation process. Therefore, the optimum temperature for the activation process should start at 450–550 °C and increase until the temperature reaches to 800 °C. Activated carbon from corncobs at 450–550 °C contained a suitable amount of volatile matter, 17–25%, for pore development. The Langmuir and Dubinin–Radushkevich (D–R) adsorption models were used to study the equilibrium isotherms, the isotherm constants and the adsorption capacity of monoethylene glycol by corncob activated carbon and commercial activated carbon. The values of Langmuir isotherms Qmax of corncob activated carbon and commercial activated carbon were , respectively. The D–R isotherms were described the adsorption capacity and the free energy (E) of adsorption. The values of E (kJ mol−1) confirmed that monoethylene glycol adsorption by corncob activated carbon and commercial activated carbon was a physisorption.
    No preview · Article · Feb 2009 · Colloids and Surfaces A Physicochemical and Engineering Aspects
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    ABSTRACT: Micro–mesoporous activated carbons were prepared from various agricultural wastes by physical activation. Agricultural wastes such as macadamia nut-shell, corncob, bagasse bottom ash, sawdust fly ash and rice husk fly ash, were optimized and processed to obtain the highest surface area. The effects of the amount of volatile matter in char, the activating agent, the activating temperature and kind of raw materials were investigated in terms of porosity development. It was found that the amount of volatile matter, 17–25% or 300–500 °C suitable for pore development depended on the type of raw material. In addition, the activating agents (CO2 and steam) can differentially improve the porosity of the materials. Corncob and sawdust fly ash activated by CO2 and macadamia nut-shell and bagasse bottom ash activated by steam obtained the same high surface area. Among these materials, bagasse bottom ash and sawdust fly ash had a mesopore volume than other materials including commercial activated carbon. Therefore, both of these materials can be alternative adsorbents to adsorb large molecule of organic compounds.
    No preview · Article · Jul 2008 · Journal of Analytical and Applied Pyrolysis
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    ABSTRACT: Wood shaving fly ash was used as an alternative adsorbent for gold preconcentration from gold slag. The maximum gold adsorption capacity of wood shaving fly ash washed with tap water (WSFW) at 20, 30, 40, and 60 degrees C was 8.68, 7.79, 7.44, and 7.25 mg(Au)/g(adsorbent), respectively, while of activated carbon it was 76.78, 60.95, 56.13, and 51.90 mg(Au)/g(adsorbent), respectively. Deionized water at 100 degrees C could elute gold adsorbed onto WSFW to 71%. The effect of the increasing temperature of water, 30, 60, and 100 degrees C, implied that the adsorption mechanism was mainly physical adsorption. The negative values of enthalpy change (DeltaH) and free energy change (DeltaG) indicated an exothermic and spontaneous process, respectively. The positive values of entropy change (DeltaS) indicated increasing disorder of the system. The advantages of wood shaving fly ash are the purification of gold and the easier recycling of gold from the gold-adsorbed adsorbent.
    No preview · Article · Aug 2005 · Journal of Colloid and Interface Science
  • A. Aworn · P. Thiravetyan · W. Nakbanpote
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    ABSTRACT: The aim of this research is to recover gold from the slag of jewellery industry by using sawdust fly ash as a low cost adsorbent. The gold was extracted from the slag by cyanidation process. The slag extraction by cyanidation process was higher at feeding O2 gas (30 mg 1 1) than air (8 mg l-1) to 53%. The sawdust fly ash (SDF) used was divided into three groups; (1) SDF: no treatment, (2) SDF/water: washed with an excess of water, and (3) SDF/H2SO4: soaked with 0.1 N H2SO4. Although SEM photographs of the three adsorbents appeared similar results but BET surface of SDF (104.40 m2 g-1) was lower than SDF/H2SO4 (295.30 m 2 g-1) and SDF/water (395.70 m2 g -1), respectively. However, statistic analysis significantly at P≤0.05 indicated that the gold-cyanide adsorption by SDF/H2SO 4 and SDF/water (78%) were higher than SDF (52%). This can be explained that SDF/H2SO4 and SDF/water had higher surface area than SDF. The results also showed that pre-treatment of SDF by sulphuric acid or water could increase the gold adsorption efficiency. Therefore, SDF/water was selected for study the equilibrium time, pH and maximum adsorption capacity. The SDF/water rapidly adsorbed gold within 15 minutes and reached equilibrium time at 2 hours. There was no difference of gold adsorption at the system pH of 10 and 11. The maximum gold adsorption capacity of SDF/water at 20°C, 30°C, 40°C and 60°C were 8.68, 7.79, 7.44 and 7.25 mg Au g-1, respectively and activated carbon were 76.78, 60.95, 56.13 and 51.90 mg Au g-1, respectively. Thermodynamic parameters indicated the exothermic nature of adsorption The process was spontaneous and favourable. Gold adsorbed onto SDF/water could also elute by deionized water. Therefore, this implied that the mechanism was physical adsorption.
    No preview · Article · Jan 2005