Papers by Author: Sitthisuntorn Supothina

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Authors: Sittinun Tawkaew, Tawan Sooknoi, Angkhana Jaroenworaluck, Thammarat Panyathanmaporn, Sitthisuntorn Supothina
Abstract: A photocatalytic system for wastewater treatment from textile industries was constructed and tested for its efficiency. The system consisted of two units – a photoreactor for dye decomposition and a catalyst recovery unit. The photoreactor was an annular plug flow photoreactor under irradiation of 36 W Toshiba blacklight. The catalyst recovery unit was 42 L of sediment tank for TiO2 catalyst recovery. In our study, a Cibra Cron red R-W 150% (an anionic azo dye) was used to prepare a synthetic textile wastewater. The experimental parameters such as flow rate, pH, dye initial concentration, catalyst loading and setteled time that affected the system performance were investigated. The photodegradation kinetics were found to follow the Langmuire - Hinshelwood model and also depended on the TiO2 concentration and the pH. The optimum condition for photocatalytic decomposition was at pH 3 and at 1 g/L of TiO2 catalyst loading. The reaction rate constant, k and the adsorption constant, K for the scale-up photoreactor were 3.345 mg/L-min and 0.0204 L/mg, respectively. For the catalyst recycle unit, the overflow and underflow concentration of the TiO2 catalyst were 2.00 and 0.002 mg/L, respectively, at 100 ml/min of inlet flow rate, 50 ml/min of overflow and 50 ml/min of underflow.
Authors: O. Nimittrakoolchai, Thammarat Panyathanmaporn, Angkhana Jaroenworaluck, Sitthisuntorn Supothina
Abstract: Adhesion between TiO2 coatings and the fabrics was improved by using a silane adhesive agent. To investigate a suitable method of applying adhesive agent, two different coating methods were conducted. The silane was either mixed with Ti precursor for fabric dipping, or coated onto the fabrics before dipping them in a Ti precursor. The effect of Ti precursor, sol and colloid, on coating morphology was also studied. It was found that continuous coating with no cracking was obtained when the fabrics were pre-treated with the silane. The TiO2 coatings had good adhesion, regardless of the method of applying the adhesive agent. Thick, cracked coatings were obtained from Ti colloid precursor while continuous coating was obtained from the Ti sol precursor.
Authors: Thammarat Panyathanmaporn, Angkhana Jaroenworaluck, Sitthisuntorn Supothina, Rung-Arun Chumnanklang, Kannikar Juengsuwattananon, Supatra Jinawath, Tawan Sooknoi, Siriya Jiamsakul, Sittinun Tawkaew
Abstract: Ag-doped TiO2 catalyst employed as the oxidation catalyst candidate was prepared by two methods, co-precipitation and dip coating method. Co-precipitation method was conducted by adding AgNO3 into the titanium precursor before gelation and then the obtained solution was coated on the alumna beads. Dip coating method was conducted by coating the first layer on alumina beads with titanium precursor followed by coating the second layer with AgNO3. The fired Ag-doped TiO2 coated on alumina beads was used as catalyst for catalytic oxidation of methanol and carbon monoxide by using oxygen as oxidizing agent in a gas-phase reactor. The methods of catalyst preparation were found to affect the catalytic efficiency. Dip coating method showed better oxidation reaction as Ag-doped TiO2 catalysts were well dispersed on the alumina beads.
Authors: N. Atthi, O. Nimittrakoolchai, Sitthisuntorn Supothina, J. Supadech, W. Jeamsaksiri, A. Pankiew, C. Hruanun, Amporn Poyai
Abstract: Two different viscous coating materials, which are Polydimethylsiloxane (PDMS) mixed with 10%wt of Dicumylperoxide (DCP), and Semifluorinate Silane (SFS), were applied to silicon micro-asperity. The cosine’s Young and viscosity of those coating materials are -0.3584,-0.3496 and 3.176x10-3, 1.339 x10-3 Pas, respectively. The rough surfaces with nine asperity shapes were studied. The results shown that, pillar shape has an effect on water contact angle (WCA): Stripe asperity cannot make the average WCA greater than 150. When consider the pillar asperity, the WCA falls between 152 and 157, which exhibits a superhydrophobic surface property. However, actual WCA of the micro-asperity coated with PDMS+10%wt of DCP is lower than that coated with SFS around 1 to 7. High viscous material makes the asperity size bigger than the design and decreases the WCA: the low viscous material is more suitable for coating on the asperities.
Authors: Ramida Rattanakam, Pinitpon Pituya, Mantana Suwan, Sitthisuntorn Supothina
Abstract: This paper reports studies to investigate the relationships between hydrophobicity of biochar surface and soil water retention. The studied biochars were produced from acacia wood, cashew wood and bamboo. The resulting materials were oxidized via liquid oxidation to generate hydrophilic biochars containing oxygenated functional groups on the surface. All biochars were characterized and their ability as soil additives to enhance water retention was assessed. Our results suggest that hydrophobicity/hydrophilicity of biochars is not the major factor governing water retention ability of this particular soil. However, hydrophilicity of biochar helps improve soil permeability by providing better wettability to the soil.
Authors: N. Atthi, O. Nimittrakoolchai, W. Jeamsaksiri, Sitthisuntorn Supothina
Abstract: In this paper, we report innovative gloves that are coated with hydrophobic film such that the outer surface of the gloves is hydrophobic. A coating precursor containing polymethyl hydrogensiloxane, silica nanoparticle, semifluorinated silane and Pt-catalyst was painted onto the gloves. The coated gloves were kept at room temperature for 12 h to make the film dry, and then tested for their chemical resistance with 10 M NaOH, conc. HCl, conc. H2SO4 and conc. HNO3 solutions, as well as the standard buffered solutions (pH = 1, 4, 10, and 12) at 25oC by dropping the chemicals onto the coated gloves. It was found that the nitrile gloves had similar contact angles to the latex gloves when tested with the standard buffered solutions while the nitrile gloves had higher contact angles compared to the latex gloves when tested with different aqueous-based hazardous chemicals. The nitrile gloves coated with the hydrophobic film showed high acid droplet contact angle, leaving behind much lesser damage from hazardous chemicals.
Authors: Mantana Suwan, Pantip Sakchaikul, Sorachon Yoriya, Sitthisuntorn Supothina
Abstract: Solar-reflective yellow pigment was synthesized by a solid-state reaction of the Sm2O3 and CeO2 in the presence of the (NH4)6Mo7O24 employed for the Mo doping. The raw materials were wet milled in acetone for 6 h to acheive a homogeneous slurry followed by calcination at 1100, 1300 and 1500 °C for 6 h. The effect of the Mo doping was investigated by adding 10, 15, 20, 25 and 30 wt.% (NH4)6Mo7O24. XRD analysis of the undoped product revealed the formation of Sm2Ce2O7 at 1300 °C along with the unreacted Sm2O3 and CeO2, and revealed the completed reaction at 1500 °C. The addition of (NH4)6Mo7O24 resulted in the formation of Sm2Ce2-xMoxO7+δ, where x = 0.02, 0.03, 0.04 and 0.05 depending on the amount of the Mo dopant employed. The doping also significantly affected the product’s color; it turned from ivory white to yellow with the increase of dopant content up to 20 wt.% and became dark green afterward. Increasing firing temperature from 1100 to 1500 °C led to brighter yellow due to the substitution of Mo6+ for Ce4+. At the optimum synthesis condition, i.e. 20 wt.% doping and 1500 °C firing temperature, the product was most yellowish and had 69.2 % near-infrared reflectance.
Authors: Sunisa Jindasuwan, Pim Chakornnipit, Sitthisuntorn Supothina
Abstract: For ceramic industry, efflorescence is undesirable and cannot be completely eliminated from the finished products. The efflorescence is caused by soluble salts in the raw material and mostly appears as white deposit at the product’s surface. In this research, the removal of sulfate in the raw materials was studied. In addition, the sulfate ions were immobilized by forming a water-insoluble compound. The sulfate ions in the raw materials and fired products were extracted by distilled water, and the concentration was determined by using a UV-visible spectroscopy following the ASTM C1580-09 standard. Three sources of the raw materials from Tambon Suan Phung, Ratchaburi, Tambon Mae Win and Mae Ta, Chiang Mai, were analyzed for sulfate concentrations. The clay from Tambon Suan Phung, Ratchaburi which had the highest sulfate concentration was selected for further study on the effect of inhibitor and firing temperature on efflorescence inhibition. To reduce solubility of the sulfate, three kinds of inhibitor, i.e. barium chloride, barium carbonate and barium hydroxide, were added into the raw material at various concentrations, i.e. 0.5, 1.0, 1.5 and 2.0 wt% and homogeneously mixed by ball milling followed by the addition of distilled water to prepare the clay slip. The clay products were mold casted to 1 x 1 x 3 inch3 in size. Then, they were fired at 800, 900 and 1000 °C. It has been revealed that the addition of barium carbonate at 2 wt%, which is the highest amount employed in this study, and firing temperature of 900 °C resulted in least sulfate leaching due to the formation of water-insoluble barium sulfate. To perform a field test, the fired samples with and without the addition of barium carbonate were immersed in water for 4 months. The efflorescence was observed on the sample without barium carbonate within the 1st month. In contrast, with the addition of barium carbonate, no efflorescence was observed after testing for 4 months.
Authors: O. Nimittrakoolchai, Sitthisuntorn Supothina
Abstract: Due to excellent photocatalytic and optical properties of titanium dioxide (TiO2), it has been applied in several products such as food packaging plastics, materials for vehicles or for buildings and sunscreen-protecting cosmetics. In this present work, the synthesized as well as commercial TiO2 was coated onto a household curtain fabric for anti-microbial and ultraviolet (UV) shielding functions. The coating was performed by inducing the deposition of TiO2 layer from the Ti precursor onto the fabric surface pre-treated with silane adhesive agent so as to improve the adhesion. Ag nanoparticles were also incorporated in some samples to further improve the antibacterial function. Anti-bacterial activities of the coated fabric were evaluated by standard qualitative test (the Kirby-Bauer test (AATCC 147)). Efficiency for UV shielding was evaluated by measuring a UV-Vis reflection of the coated fabrics both before and after subjecting to several washing cycles. The result showed that the TiO2-coated fabrics developed had potential as antibacterial and UV shielding for the curtain industry.
Authors: Sunisa Jindasuwan, Nattinee Sukmanee, Chanida Supanpong, On-uma Nimittrakoolchai, Sitthisuntorn Supothina
Abstract: A mulberry paper has been used to produce many consumer products such as lantern, card, packaging and decorating articles. Similar to other cellulosic materials, the mulberry paper bears abundant hydroxyl groups on its surface. Besides easily ignited, it can absorb water or humidity. To improve its thermal stability and to reduce deterioration caused by moisture adsorption, the mulberry paper was coated with a flame-retardant substance which was monoammonium phosphate (MAP) and a hydrophobic substance which was poly (methylhydrogen siloxane) (PMHS). The coating was conducted by immersing the mulberry paper in coating solution for 2 min followed by drying at 50 °C for 30 min. By varying a weight ratio of the PMHS and MAP, the PMHS:MAP weight ratio of 10:10 was found to be the optimum coating solution. The coated mulberry paper had good thermal property according to the thermogravimetric analysis. The uncoated mulberry paper showed residue of about 21% while the coated mulberry paper showed the increased residue of more than 50%. The burning test revealed that the coated mulberry paper was self-extinguished after removal of the ignition source while complete burning was observed on the uncoated paper. Moreover, it was water repellent with a water contact angle of 101.48 ± 5.81 degrees.
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