Surachai Karnjanakom

Preparing hydrophobic nanocellulose-silica film by a facile one-pot method

Hydrophobic nanocellulose-silica film was successfully prepared by a facile one-pot method using tetraethoxysilane (TEOS) and dodecyl triethoxylsilane (DTES). Morphological characterization of the hydrophobic nanocellulose-silica (NC-SiO2-DTES) film showed well self-assembled DTES modified silica spherical nanoparticles with the particle sizes in the range of 88-126nm over the nanocellulose film. The hydrophobicity of the NC-SiO2-DTES film was achieved owing to the improvement of roughness of the nanocellulose film by coating dodecyl- terminated silica nanoparticles. An increase in DTES loading amount and reaction time increased the hydrophobicity of the film, and the optimum condition for NC-SiO2-DTES film preparation was achieved at DTES/TEOS molar ratio of 2.0 for 8h reaction time. Besides, the NC-SiO2-DTES film performed superoleophilic property with octane and hexadecane contact angles of 0°. It also showed an excellent hydrophobic property over all pH values ranged from 1 to 14.

A green method to increase yield and quality of bio-oil: ultrasonic pretreatment of biomass and catalytic upgrading of bio-oil over metal (Cu, Fe and/or Zn)/γ-Al2O3

A green method is developed to increase the yield and quality of bio-oil by ultrasonic pretreatment of biomass followed by in situ catalytic upgrading of bio-oil over metal (Cu, Fe and/or Zn)/γ-Al2O3. It is found that the yield of bio-oil is increased up to 10 wt% after cedar is pretreated by ultrasound before pyrolysis. Various metals (Cu, Fe and Zn) are loaded on γ-Al2O3 and applied for upgrading the bio-oil derived from the pyrolysis of pretreated cedar. It is found that the catalysts promote the conversion of oxygenated compounds into aromatic and aliphatic hydrocarbons. In particular, production of monocyclic aromatic hydrocarbons such as benzene and toluene is favored. The best catalytic activity is achieved by using 2.5 wt% Zn/γ-Al2O3 with a maximum hydrocarbon yield of 80.3%. The catalyst is reused for up to four cycles. The results show that the catalysts after regeneration by calcination at 550 °C for 30 min exhibit long-term stability for upgrading of bio-oil.

A facile one-step way for extraction of nanocellulose with high yield by ball milling with ionic liquid

Abstract93.1% yield of nanocellulose was successfully extracted from cellulose powder (CP) by planetary ball milling in the presence of ionic liquid (IL) of 1-butyl-3-methylimidazolium chloride (BMIMCl). The morphology of nanofibrillated cellulose present in fibrous network with 10–25xa0nm in diameter and micrometer scale in length and the chemical composition and crystal structure were maintained as cellulose type I. At 600xa0°C degradation temperature, the residue amount of the obtained nanocellulose was about 55% more that of CP, implying it had higher thermal stability. The used BMIMCl was recovered and reused at least 4 times. The nanocellulose obtained by using the recovered IL also demonstrated the same properties as those from the fresh one. For comparison, another kind of IL of 1-ethyl-3-methylimidazolium acetate (EMIMOAc) was also used in this study. It is found that the ball milling of cellulose in the presence of IL is an effective and environmental friendly way for the production of nanocellulose with high yield.

Selective production of aromatic hydrocarbons from catalytic pyrolysis of biomass over Cu or Fe loaded mesoporous rod-like alumina

The selective production of aromatic hydrocarbons from bio-oil derived from the fast pyrolysis of sunflower stalks over Cu or Fe-modified mesoporous rod-like alumina catalysts was investigated. Uniform mesoporous rod-like alumina with different pore sizes were successfully synthesized using a hydrothermal method with the assistance of Pluronic P123 surfactant. A high relative total hydrocarbon amount of about 59% in the upgraded bio-oil was obtained when pure mesoporous Al2O3 with a uniform pore size of 5.81 nm was used. Mesoporous Al2O3 with a larger pore size resulted in more polycyclic aromatic hydrocarbons (PAHs) such as indenes and naphthalenes being generated. Cu or Fe loaded Al2O3 with a loading amount in the range of 1–2.5 wt% showed a high selectivity towards monocyclic aromatic hydrocarbons (MAHs) such as benzene, toluene and xylenes (BTXs) over 80%. By using 2.5 wt% Cu/Al2O3-0.01, the highest relative total hydrocarbon amount reached 89%, which consisted of about 84% aromatic hydrocarbons and 4.9% aliphatic hydrocarbons. Both catalysts showed good catalytic stability and regeneration properties. A catalytic system with high effectiveness and long-term stability was expected to be obtained to convert the oxygenated compounds in bio-oil to high value-added hydrocarbons.

Amphiphobic nanocellulose-modified paper: fabrication and evaluation

Amphiphobic nanocellulose-modified paper with high durability is successfully fabricated using a facile two-step method. Firstly, nanocellulose-modified paper is prepared through dipping filter paper, i.e., glass microfiber (GM) filter paper and polytetrafluoroethylene (PTFE) filter paper in a dilute nanocellulose dispersed solution. Subsequently, the nanocellulose-coated paper is treated with trichloro(1H,1H,2H,2H-tridecafluoro-n-octyl)silane (FOTS) via chemical vapor deposition. The obtained paper is found to have superhydrophobicity and oleophobicity, repelling both polar and non-polar liquids, on which the drops of water and non-polar liquids with high molecular weight become marble shaped, and the contact angles of water and n-hexadecane reach 156° and 144°, respectively. Furthermore, such amphiphobic nanocellulose-modified papers exhibit excellent surface durability in several environments including at various temperatures, and in acid and alkaline solutions, salt solutions and seawater. In addition, such amphiphobic nanocellulose-modified papers show good repellant properties for several kinds of liquids from our daily life. With outstanding protection to a diverse range of liquids, the amphiphobic nanocellulose-modified paper can be applied in the fields of self-cleaning, anti-bacterial, and anti-corrosion materials.

Adsorption behavior of As(V) from aqueous solution by using Fe3+–MnO4−-modified activated carbon (Leucaena leucocephala (Lam) de Wit)

The objective of this work was to prepare a highly efficient adsorbent from Leucaena leucocephala (Lam) de Wit via pyrolysis and chemical activation (H3PO4) with a modification (MnO4− and Fe3+) process for HAsO42− removal from aqueous solution. It has been found that the activated carbon prepared by pyrolysis activation at a temperature of 500xa0°C for 2xa0h (502) exhibited the best performance for the adsorption of the I2 number (505.69xa0mgxa0g−1) and Fe3+ (28.18xa0mgxa0g−1). After carbonized carbon (CC) and 502 were modified by using MnO4− and Fe3+, the HAsO42− adsorption capacity was increased up to 100 times when compared with CC and 502 without chemical modification. The pH range of about 6–7 was appropriate for Fe3+ and the HAsO42− adsorption. For the regeneration of adsorbent, the Fe3+ and HAsO42− could be successfully desorbed from the CC surface by using 1.0xa0molxa0L−1 HNO3 solution. The adsorption data were well described by the Langmuir and pseudo-second-order kinetic models, which could be confirmed by R2 close to 1. Moreover, the adsorption behaviors were physisorption, spontaneous and endothermic, confirmed by Themkin and Dubinin–Radushkevich isotherms as well as thermodynamic studies. This research was expected to help to understand the adsorption behavior of As(V) and to provide a suitable process with high adsorption capacity.Graphical abstract

Selective conversion of fructose into 5-ethoxymethylfurfural over green catalyst

In this study, selective formation of 5-ethoxymethylfurfural (EMF) from one-pot conversion of fructose in a co-solvent of ethanol with tetrahydrofuran over green SO3H-CD carbon was investigated for the first time using an ultrasonic system. The maximum EMF yield of 74% with 100% fructose conversion was achieved in mild conditions. Moreover, the better selectivity and the longer recyclability (eight cycles) for EMF production via particular reactions such as fructose dehydration and etherification were obviously found while the formation of 5-hydroxymethylfurfual, ethyl levulinate or humins was inhibited using SO3H-CD carbon, comparing to commercial catalysts such as Amberlyst-35, SiO2-Tosic acid and Al2O3.Graphical abstract

Correction: Catalytic conversion of biomass derivatives to lactic acid with increased selectivity in an aqueous tin(II) chloride/choline chloride system

Catalytic conversion of biomass-derived carbohydrates to lactic acid (LacA) over Sn-based catalysts always shows a low selectivity (<30%) in an aqueous system, especially when SnCl2 is used as the catalyst. In this study, the catalytic activity as well as the selectivity of SnCl2 for the conversion of trioses, monosaccharides and disaccharides into LacA in the aqueous phase reaction system was found to be increased by the addition of choline chloride (ChCl). As the concentration of ChCl was 40–50%, the reaction selectivities towards LacA reached 40–77% under moderate reaction conditions (155–190 °C for 0.5–1.5 h). It is attributed to the formation of the SnCl2/ChCl complex in the H2O–ChCl system, which was indicated by (1) the pH of the solution changing to the acidic state (i.e. ∼3), (2) the SnCl2 completely dissolving in the ChCl aqueous solution, and (3) the single chemical shift in 119Sn NMR spectra. Such a SnCl2/ChCl complex served as a bifunctional acid catalyst to promote the hexose reaction pathway via [3 + 3] retro-aldol reaction into LacA. In contrast, LacA selectivity was only ∼7% in neat water under the same operational conditions since SnCl2 can be easily hydrolyzed into Sn(OH)Cl and HCl, resulting in the dehydration of hexoses into levulinic acid due to the strong Bronsted acidity of HCl. A kinetic study revealed that LacA yield was greatly affected by the reaction temperature and reached the maximum at 160–190 °C after 15–30 min. This study provides a new insight for the possible application of this H2O–ChCl system in other Lewis acid catalysis reactions by using SnCl2 as the catalyst.

Bifunctional Mg−Cu-Loaded β-Zeolite: High Selectivity for the Conversion of Furfural into Monoaromatic Compounds

Mg−Cu‐loaded β‐zeolite was prepared as an acid−base bifunctional catalyst for the conversion of furfural to monoaromatic compounds. It is found that this catalyst exhibited high selectivity towards benzene, toluene and xylenes (BTXs) production with anti‐polycyclic‐aromatic‐hydrocarbon formation as well as anti‐coking ability when compared with Cu‐loaded β‐zeolite and the parent β‐zeolite. The product distribution indicated that addition of Cu species significantly promoted the deoxygenation and aromatization of an intermediate product of furan while Mg apparently suppressed the polyaromatization. Especially, an optimum loading amount of 0.5u2005wt%Mg‐1u2005wt%Cu on β‐zeolite was obtained, which showed lower catalytic deoxygenation temperature and interestingly, only benzene was detected in the liquid product at a reaction temperature over 700u2009°C. Also, 0.5u2005wt%Mg‐1u2005wt%Cu/β‐zeolite exhibited long‐term stability for 10 cycles with 100u2009% of furfural conversion to monoaromatic compounds. The physicochemical properties of β‐zeolite after Cu and Mg loadings were characterized using N2 sorption, XRD, SEM‐EDX, TEM, H2‐TPR, UV‐Vis, XPS, NH3‐TPD and CO2‐TPD techniques. The significant changing of acidity and basicity of β‐zeolite were found after Cu and Mg loadings, which should be the main factors for the improvement of activity, selectivity and stability of the developed catalyst.