Nawin Viriya-empikul

Waste shells of mollusk and egg as biodiesel production catalysts.

The solid oxide catalysts derived from waste shells of egg, golden apple snail, and meretrix venus were employed to produce biodiesel from transesterification of palm olein oil. The shell materials were calcined in air at 800 degrees C with optimum time of 2-4h to transform calcium species in the shells into active CaO catalysts. All catalysts showed the high biodiesel production activity over 90% fatty acid methyl ester (FAME) in 2h, whilst the eggshell-derived catalyst showed comparable activity to the one derived from commercial CaCO(3). The catalytic activity was in accordance with the surface area of and the Ca content in the catalysts.

Production of bio-hydrogenated diesel by catalytic hydrotreating of palm oil over NiMoS2/γ-Al2O3 catalyst.

Catalytic hydrotreating of palm oil (refined palm olein type) to produce bio-hydrogenated diesel (BHD) was carried out in a continuous-flow fixed-bed reactor over NiMoS2/γ-Al2O3 catalyst. Effects of dominant hydrotreating parameters: temperature: 270-420°C; H2 pressure: 15-80 bar; LHSV: 0.25-5.0 h(-1); and H2/oil ratio: 250-2000 N(cm(3)/cm(3)) on the conversion, product yield, and a contribution of hydrodeoxygenation (HDO) and decarbonylation/decarboxylation (DCO/DCO2) were investigated to find the optimal hydrotreating conditions. All calculations including product yield and the contribution of HDO and DCO/DCO2 were extremely estimated based on mole balance corresponding to the fatty acid composition in feed to fully understand deoxygenation behaviors at different conditions. These analyses demonstrated that HDO, DCO, and DCO2 reactions competitively occurred at each condition, and had different optimal and limiting conditions. The differences in the hydrotreating reactions, liquid product compositions, and gas product composition were also discussed.

Conversion of fructose, glucose, and cellulose to 5-hydroxymethylfurfural by alkaline earth phosphate catalysts in hot compressed water

The phosphates of alkaline earth metals (calcium and strontium) synthesized by precipitation process in acetone-water media system were used as catalysts for converting fructose, glucose, and cellulose to 5-hydroxymethylfurfural (HMF) under hot compressed water condition. It was found that the phosphates of calcium and strontium effectively catalyzed the HMF formation from fructose and glucose dehydration and cellulose hydrolysis/dehydration reaction, as compared with the non-catalytic system. The XRD analysis confirmed the CaP(2)O(6) and α-Sr(PO(3))(2) crystalline phases of the catalyst samples, while acid strength of both catalysts was in a range of +3.3 ≤ H(0) ≤ +4.8. From the study, CaP(2)O(6) and α-Sr(PO(3))(2) showed similar catalytic performance toward the dehydration of sugars, providing the HMF yields of 20-21% and 34-39% from glucose and fructose, respectively; whereas the total yield of glucose and HMF from the hydrolysis/dehydration of cellulose over α-Sr(PO(3))(2) (34%) was higher than that over CaP(2)O(6) (17.4%).

Catalytic behaviors of Ni/γ-Al2O3 and Co/γ-Al2O3 during the hydrodeoxygenation of palm oil

The deactivation and regeneration behaviors of Ni/γ-Al2O3 and Co/γ-Al2O3 catalysts in the hydrodeoxygenation (HDO) of palm oil were investigated at 573 K and 5 MPa in a trickle bed reactor. The catalysts were prereduced at 773 K for 3 h before the HDO experiments. The catalysts exhibited good catalytic activity (>90% yield) and remained stable for 100 h on-stream. Nevertheless, after 150 h on-stream, the product yield gradually decreased from 92.2 to 76.2% over the Ni catalyst and dramatically declined from 88.6% to ca. 56.6% over the Co catalyst. The combined decarbonylation and/or decarboxylation (DCOx) reactions were dominant over the HDO reaction when the reaction was catalyzed by the Ni catalyst. Meanwhile, the contribution of DCOx and HDO reactions was nearly comparable over the Co catalyst. The XRD and XANES analyses confirmed the partial formation of metallic nickel or cobalt after prereduction and the further in situ reduction during the HDO experiments, suggesting the coexistence of the metal and metal oxides on the catalyst surfaces. The XRD and TEM analyses revealed some sintering of the nickel and cobalt particles during the time course of reaction. Based on the TPO analysis, the carbon deposition rate on the cobalt catalyst was faster than that on the nickel catalyst and would be the major reason for the catalyst deactivation, and the sintering was the minor one. Additionally, the regeneration under air at 773 K followed by reduction in H2 at 773 K can completely restore the catalytic activity.

Sr–Mg Mixed Oxides as Biodiesel Production Catalysts

The Sr–Mg basic catalysts were developed for biodiesel production through transesterification of palm oil with methanol. The evidence for synergistic effects between active Sr and Mg species was clearly demonstrated by transesterification tests over a series of Sr–Mg catalysts with varied Sr‐to‐Mg molar ratios. The catalyst properties were characterised by means of temperature‐programmed desorption of CO2 (CO2‐TPD), N2 sorption, XRD, SEM and TEM experiments. The super strong basic site was formed in Sr–Mg catalysts through a partial solid state reaction induced by thermal treatment at 600 °C. The new basic site, together with the original basic site from SrO (average basic site density=757 μmol m−2), effectively catalysed a transesterification reaction at mild conditions. Biodiesel containing 96 % methyl esters was obtained at reaction conditions of 75 min, 60 °C, 0.1 MPa, 3 wt. % catalyst loading and a methanol‐to‐oil ratio of 6:1, and the catalyst exhibited good reusability. Improved surface areas and porosities were also achieved compared to the unsupported SrO. Density functional theory (DFT) calculations of methylpropanoate adsorption on SrO, MgO and Sr/MgO showed that the adsorption energies of all adsorbate–surface complexes corresponded well with the experimental catalytic activity, which increased in the order MgO

Effects of kraft lignin on hydrolysis/dehydration of sugars, cellulosic and lignocellulosic biomass under hot compressed water.

The effect of Kraft lignin presenting on the hydrolysis and dehydration of C5 and C6 sugars, cellulose, hemicelluloses and biomass under hot compressed water (HCW) in the presence of H3PO4 catalyst was intensively studied. The lignin strongly inhibited the acid hydrolysis of cellulose and hemicellulose to glucose and xylose, respectively. Interestingly, the admixed lignin markedly promoted the isomerization of glucose to fructose, and dehydration of fructose (except at the low catalyst loading), resulting in high 5-hydroxymethylfurfural yields. Nonetheless, lignin inhibited the hydrolysis of xylan to xylose and dehydration of xylose to furfural. Moreover, the acidity of the system significantly affects the hydrolysis/dehydration of biomass. It was revealed that the presence of lignin strongly interfered the yields of sugars and furans produced from raw corncob, while the delignified corncob provided significant improvement of product yields, confirming the observed role of lignin in the biomass conversion system via sugar platforms.

Shape and surface properties of titanate nanomaterials influence differential cellular uptake behavior and biological responses in THP-1 cells

We investigated cellular uptake behavior and biological responses of spherical and fibrous titanate nanomaterials in human monocyte THP-1 cells. Two titanate nanofibers (TiNFs), namely TF-1 and TF-2, were synthesized from anatase TiO2 nanoparticles (TNPs) via hydrothermal treatment. The synthesized TiNFs and TNPs were thoroughly characterized for their size, crystallinity, surface area and surface pH. TF-1 (∼2 µm in length) was amorphous with an acidic surface, while TF-2 (∼7 µm in length) was brookite with a basic surface. The results demonstrated that none of these titanate nanomaterials resulted in significant cytotoxicity, even at the highest doses tested (50 µg/ml), consistent with an absence of ROS generation and lack of change of mitochondrial membrane potential. While no cytotoxic effect was found in the titanate nanomaterials, TF-2 tended to decrease the proliferation of THP-1 cells. Furthermore, TF-2 resulted in an inflammatory cytokine response, as evidenced by dramatic induction of IL-8 and TNF-α release in TF2 but not TF-1 nor TNPs. These results suggest that shape of titanate nanomaterials plays an important role in cellular internalization, while surface pH may play a prominent role in inflammatory response in THP-1 cells.

The Effect of Calcium-Based Salt on Hydrothermal Carbonization of Corncob

Corncob represents a great potential as a raw material for the production of high-value added chemicals, fuels and other industrial products. Thus, corncob is suitable residue for study molecular structure through the pretreatment method. In this study, the effect of calcium-based salts on the hydrothermal carbonization (HTC) of corncob were studied at 160, 180, and 200 °C for 2 h. CaSO4 and Ca3(PO4)2 were used as a reaction medium. Hydrochar was characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and ATR-Fourier transform infrared spectroscopy (ATR-FTIR). Characteristics of the hydrochar varied with calcium-based salt. Cellulose crystallinity in hydrochar decreased dramatically and carbon content in hydrochar obviously increased when Ca3(PO4)2 and CaSO4 were added, respectively. In case of hydrothermal at 180°C with Ca3(PO4)2 and CaSO4, the carbon microsphere was occurred.

Effect of Alkaline Activation on Low Grade Natural Kaolin for Synthesis of Zeolite A

The conventional technique to synthesizes zeolite A from kaolin is calcination. However, this technique has one drawback since, the impurities in kaolin, such as muscovite and quartz, remain. Therefore, the hydrothermal process without calcination is used to synthesize high purity zeolite A. Hydrothermal synthesis without calcination can be separated into two steps, namely first and second hydrothermal steps. Alkaline activation reaction in the first hydrothermal step was used to study the effect of NaOH concentration ranging from 4M, 6M, 8M, 10M to 12M at 200°C for 3 hours. In this step, sodium aluminosilicate (cancrinite and nepheline hydrate) was produced and then dissolved in HCl. After filtration, the impurity was removed, and adjusted for neutral pH of 7 to form amorphous aluminosilicate gel. For the second hydrothermal step, amorphous gel was mixed with NaOH (1-4M) to form zeolite A at 90°C for 3 days. The x-ray diffraction (XRD) and Scanning Electron Microscope (SEM) were used for characterization.

Fantastic Carbon Material for Nickel/Carbon Support Catalyst Reducing via Calcination Enhanced with Hydrothermal Carbonization

In generally, the metal catalyst which synthesis by conventional techniques is usually in metal oxide form or easily oxidize in the air thus the metal catalyst must reduce to metallic form before using. It was complex process and dangerous. In the research, Carbon material from cattail flower (CF) were used as supporter of Nickel/Carbon supported metal catalyst (Ni/C). This research were studied effect of used carbon material from CF as supporter of Ni/C and varying nickel loading. The Ni/C catalyst were prepared by hydrothermal, impregnation and calcination process. Firstly, Dried CF has been pretreat via hydrothermal process with optimized condition at 180°C for 8h. Then, the nickel solution was added to support via impregnation method by varying Ni loading from 20 to 60 wt% of supported. Finally, the sample has been pelleted into 0.5mm-Ni/C pellet and calcined at 900°C for 2h under nitrogen atmosphere. Ni/C were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), surface area and pore size distribution was determined by N2 adsorption. The result indicate that nickel particle on Ni/C were in the free metal from without reduction and well dispersed on supported surface. Particle size and surface area of Ni/C were decreases at the increase metal loading. Nickel/Carbon supported metal catalyst were ready to use and could be controlled particle size, surface area and crystallinity by metal loading.