Choojun, Kittisak
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Item type:Publication, Preparation, characterization and photocatalytic properties of rubber-TiO2-rGO composite sheets for dye decomposition in wastewater(2017-01-01); In this work, rubber-TiO<inf>2</inf>-rGO (RT-rGO) composite sheets were successfully prepared by a simple latex mixing-casting method using TiO<inf>2</inf> and natural rubber latex with different amounts of rGO loading. The prepared RT-rGO sheet samples were characterized by XRD, FT-IR, Raman, SEM and EDS techniques. The photocatalytic properties of the prepared RT-rGO sheets as catalyst were evaluated using methylene blue (MB) dye solution under UV light irradiation. The result indicated that all the composite sheets loaded with rGO had better photocatalytic activities than the sheet without rGO loading. RT-rGO6.2% sheet showed the highest removal efficiency of 93.3% which has the rate constant (kapp) as 98.2 times higher than the unloaded sheet. Furthermore, the efficiency of the RT-rGO sheet upon the repeated usage was also studied. The result indicated that the sheet could be easily used, recovered and reused many times with no need for the cleaning in between successive uses. Thus, the RT-rGO sheet appears to be an attractive-material for the wastewater treatment or the water purification industry. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, High photocatalytic performance of 3D porous-structured TiO2@natural rubber hybrid sheet on the removal of indigo carmine dye in water(2019-08-01); ; Sriwong, SukanpiromDue to the high efficiency of photocatalytic process for the environmental treatments, titanium dioxide (TiO<inf>2</inf>) is a popular used as photocatalyst material. However, the practical uses of TiO<inf>2</inf> in powder form have some drawbacks as well as the difficult reusability. In this work, 3D porous-structured TiO<inf>2</inf>@natural rubber (TNR) hybrid sheets with high photocatalytic performance were presented. TNR hybrid sheets prepared by a facile and low-cost method, which is based on the mixing of natural rubber (NR) latex (60% high ammonia) and ammoniacal TiO<inf>2</inf> (P25) suspension, followed by vacuum filtration through a sintered glass template to make a 3D porous network structure on the surface of the sheets. The obtained TNR sheet samples were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDX), X-ray diffractometer (XRD) and reflection Fourier transformed infrared spectroscopy (FT-IR) techniques. The results showed that the surface morphologies of TNR hybrid sheets appeared as porous-structured which had high roughness and with various tiny pores on the surface. The photocatalytic properties of the prepared TNR hybrid sheets were tested using indigo carmine (IC) dye under UV light irradiation. It was found that the highest photodegradation efficiency was achieved with the TNR_5 wt% hybrid sheet sample. Compared with the sheets reported in previous works, the TNR sheet shows higher efficiencies than those sheets due to its higher amount of TiO<inf>2</inf> particles at the surface, more porous structure with high rough surface, and abundance of tiny pores on the TNR sheet surface. Moreover, the recyclability and stability of TNR sheet indicated that upon using 10 cycles (remains 98% efficiency), in which the stability of the sheet surface well-confirmed by SEM and XRD techniques, as well. From above the study, this 3D porous-structured TNR hybrid sheet could be a new alternative strategy for the water or wastewater treatment in industry concerning with the easy use, recovery, reusability and stability of the photocatalysts. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of cobalt complex precursors on reactivity of cationic cobalt catalysts: Cyclohexane dehydrogenation(2019-05-10); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of synthesized Ag nanoparticles by using the different amounts of polyvinylpyrrolidone for Ag-natural rubber hybrid sheets and their antibacterial properties(2017-01-01); Ag-natural rubber (Ag-NR) hybrid sheets were successfully prepared with a very simple and low cost method. In this method, silver nanoparticles (AgNPs) were firstly synthesized by a rapid and green microwave-assisted using polyvinylpyrroridone (PVP) media. The effect of PVP weight ratios towards the size of AgNPs was also investigated. Then, Ag-NR hybrid sheet samples were prepared by latex mixing-casting method using concentrated natural rubber (NR) latex with the synthesized AgNPs colloids. The characteristic absorption, particles sizes and shapes of the obtained AgNPs were examined through UV-vis, TEM and SAED. Also, the prepared Ag-NR sheet samples were characterized using XRD, FT-IR, SEM and EDS techniques. It was found that the particles sizes of all the synthesized AgNPs had spherical-like shape, and the mean sizes were increased from 29.7 to 90.4 nm upon increasing PVP contents. EDS results showed the AgNPs were well-dispersed and impregnated into the rubber matrix. Moreover, the antibacterial properties of the prepared Ag-NR sheets were tested by agar disk-diffusion method with Gram-positive and Gramnegative bacteria as Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The results showed that the hybrid sheets exhibited excellent antibacterial properties against these bacteria, in which the zones of inhibition were also dependent on the synthesized AgNPs by utilizing the different amounts of PVP. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, TMPMgnBu(L), where L = THF, 2-MeTHF, pyridine and dimethylaminopyridine and TMP = 1,5,9-trimesityldipyrromethene: Reaction with lactide and ε-caprolactone(2017-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, TMPZnN(SiMe3)2, [TMPZn(μ-OiPr)]2 and TMPZn[OCMe2C(O)OEt]. Their role in the ring-opening of rac-lactide and ϵ-caprolactone where TMP = 1,5,9-trimesityldipyrromethene(2016-06-15); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Synthesis of nanocrystalline cobalt ferrite by the sonochemical method in highly basic aqueous solution(2017-01-01); ; This study reported the preparation of nanocrystalline CoFe2O4 in single step by the sonochemical method in highly basic aqueous solution without requiring of high temperature calcination process. To prepare nanocrystalline CoFe2O4, the mixed solution of the required molar ratio of cobalt nitrate hexahydrate (Co(NO<inf>3</inf>).6H2O) and ferric nitrate nonahydrate (Fe(NO<inf>3</inf>).9H2O) was precipitated in high concentration of sodium hydroxide medium solution (NaOH) under high intensity ultrasonic irradiation (20 kHz, 150 W/cm2). The effect of NaOH concentration (5, 10, 15 and 20 M) on phase formation, microstructure and magnetic property of CoFe2O4 was investigated. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) results showed that the as-prepared powders were single phase CoFe2O4 with cubic spinel structure. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) study showed that nanocrystalline CoFe2O4 had monosized distorted spherical morphology and an agglomeration of the nanocrystalline CoFe2O4 into nanoparticles was observed when increasing the NaOH concentration. The nanocrystalline CoFe2O4 exhibited superparamagnetic property and the saturation magnetization (Ms) obtained from vibrating sample magnetometry (VSM) was found to correlate with the crystallite size and varied from 39-45 emu/g. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Preparation and photocatalytic activities of tio2-rgo nanocomposite catalysts for mb dye degradation over sunlight irradiation(2018-01-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Investigation of the influences of reaction temperature and time on the chemical reduction of graphene oxide by conventional method using Vitamin C as a reducing agent(2017-01-01); ; Kongtaweelert, SamartThe aim of this work is to investigate the synthesis of reduced graphene oxide (rGO) aqueous suspension by a conventional heating method using vitamin C as a reducing agent. The influences of reaction temperatures (70, 90 and 100 °C) and heating times (30, 45 and 60 min) on the chemical reduction of graphene oxide (GO) were studied. Then, the obtained rGO samples were characterized by FT-IR, Raman, UV-Vis, XRD and TEM techniques. The FT-IR and Raman results showed that the reduction degree of GO to rGO was increased with the rising of the reaction temperature and time. Moreover, the UV-Vis spectra demonstrated that the absorption band at around 230 nm (π-π*) of pristine GO had shift to the longer wavelength upon the chemical reduction, indicating that GO is reduced to rGO. The optimal condition of the chemical reduction of GO to achievable rGO was the temperature of 90 °C with the 45 min of heating time. This condition yielded the rGO black aqueous suspension with the high quality and stability. Thus, this method of synthesis has an advantage of the rGO dispersion which led to many potential applications.