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This study examines sustainable agricultural development in Vietnam by focusing on rice production in the Mekong Delta. Vietnam is the third largest rice-exporting country in the world and more than 90% of rice for export is from the Mekong Delta. We attempt to identify changes in the rice industry, specifically examining farming mechanization, trends in farm operation, and farm household economy. The main structure of our study is based on our direct interviews with 420 farmer households, 81 registered large farm owners, 75 farming service providers, and local government members. We carried out those interviews in 2013 and 2014. We identified several important changes brought by technological advances, economic modernization, government policies, and environmental movements. One important finding was the increasing trend of agricultural land per farmer household, such as from 1.98 to 2.27 ha in 2010 to 2018, and the decreasing trend of labor force, which pushed up agricultural mechanization. Another point was the land law revised in 2013, which allowed farmers to borrow (no private land ownership in Vietnam) farms up to 30ha/household if registered as a &ldquo, Trang Trai&rdquo, farm. Farmers accepted the use of tractors and combine harvesters, however, rice seed sowing was not mechanized, so rice transplanters were rarely used for rice planting. Among the processes of rice production, sowing of rice seeds was the least mechanized. In order to achieve more sustainable agricultural practices, we recommend improving the mechanization of the rice seed sowing process for the Mekong Delta farmers with acceptable conditions. Another finding was positive movements among Mekong Delta researchers and farmers to improve their rice quality to be accepted as high-quality rice in the global rice market and to dispel the bad reputation of the past.

A photometric method to determine molecular oxygen in water was developed. When manganese(II) is oxidized by oxygen under alkaline conditions, the presence of polyphosphate can prevent precipitation due to a coacervate reaction. The oxidized manganese later dissolves in acid to form a pink Mn(III) species, which has a stable UV/vis spectrum. Monitoring of the oxygen concentration based on the absorbance of the pink Mn(III) species at 517 nm showed a strong correlation with both the Winkler method and an optical sensor. As a result, the present method can measure not only dissolved oxygen, but also fine bubbles oxygen in in the water sample with high reliability (0 - 26 mg dm-3, r2 = 0.9995). During this process, no significant interference from nitrite or metal ions was observed. The accuracy of the measurement was steady at high temperatures of the water samples (≤ 363 K).

Roselle seeds, a waste biomass of the roselle calyx processing industry, were utilized to recover valuable compounds of oil, vitamin E, and water-soluble saccharides. Firstly, ultrasound-assisted extraction (UAE) and conventional stirring extraction were conducted for saccharide extraction, and the advantage of UAE was confirmed. Secondly, oil, vitamin E, and saccharides extracted from Vietnamese roselle seeds by UAE were analyzed for the first time. Oil of tri-, di-, and mono-glycerides, fatty acids of linoleic-, oleic-, palmitic-, and stearic-acids, vitamin E of γ- and α-tocopherol, and saccharides of sucrose, raffinose, stachyose, etc. were identified, and the amounts of these components were compared with those in other country's roselle seeds. Thirdly, cascade extraction of oil, vitamin E, and saccharides by UAE was investigated with solvents of hexane, hexane:ethyl acetate binary solvent, and water. The results indicated that the order of using solvents was very important for high and selective extraction: the best order to recover oil (almost 100%), vitamin E (95.7%), and saccharides (86.2%) was hexane, and then water.

Neat nitrobenzene was continuously irradiated at two ultrasonic frequencies: 40 and 200 kHz, under air and argon atmosphere, respectively. Samples taken at intervals of 1, 5, 10 and 24 h were analyzed by GC-MS and decomposition products were identified. Possible reaction mechanisms are discussed. Presence of air as dissolved gas leads to oxygenated compounds such as 1,4-benzoquinone, 2,4-dinitrophenol, m-dinitrobenzene while argon inhibits the decomposition of nitrobenzene, especially at sonication times under 5 h. Based on the nature of the compounds identified we advanced a mechanism, involving a divergent splitting of unstable radical cation of NB in air and argon respectively. Thus, under air, the phenyl cation formation is preferred leading to 1,4-benzoquinone nitro-biphenyls and dinitrobenzene, while under argon, the phenyl radical formation seems to be favored, leading to phenol and diphenyl ether. The oxygenated compounds detected under argon clearly are a consequence of the nitro group splitting.

Jatropha curcas is a multipurpose plant, of which the seed kernel oil (up to 60% content) has been exploited for BDF production. In this report, we explored the various kinds of minor compounds of saccharides, phytochemicals, fatty acids (FAs), and amino acids in the seed kernel using gas chromatography/mass spectrometry (GC/MS) as their trimethylsilyl (TMS) derivatives. The homogenized seed kernels were extracted with methanol, and the extract was distributed into ethyl acetate/water phase. The components of each layer were derivatized with N, O-bis (trimethylsilyl) trifluoroacetamide (BSTFA) and their TMS derivatives were screened by GC/MS analysis. In ethyl acetate layer, the four FAs of palmitic acid, oleic acid, linoleic acid, and stearic acid were identified with total content of 12 wt% in kernel. In addition, the two tocochromanols of γ-tocopherol and γ-tocotrienol, and three phytosterols of campesterol, stigmasterol, and β-sitosterol were also identified. Meanwhile, as the main saccharide components, di-saccharide of sucrose with content of 3 wt% in kernel, tri-saccharide of raffinose, and sugar alcohol of sorbitol and myo-inositol, were identified in aqueous layer. Furthermore, metabolites of amino acid, and a series of metabolite were also identified. These results suggested that the Jatropha curcas seed kernel can be applied to cascade use for metallic soap, liquid fuel, food and medical supplement, and cosmetics in addition to biodiesel production.

We present an analytical method for dissolved oxygen based on the quantification of Mn(III) absorbance in a water sample. After Mn(II) reacts with the oxygen molecules in water, Mn(III) is formed and stabilized by hexa-metaphosphate under acidic conditions. The UV visible absorbance of Mn(III) is proportional to the oxygen concentration in the water sample. Compared to the Winkler method, the proposed method has the same accuracy (R = 0.9992 at 0 - 52 mg dm-3) but requires fewer reagents; furthermore, it does not involve titration. Interferences from nitrite and iodate were not observed. This procedure can be used to accurately and quickly determine the oxygen concentrations in different natural water sources, including seawater.

This study aimed to access the sustainable potential of inedible vegetable oil-based biodiesel systems in Northern Viet Nam by employing a life cycle sustainability assessment index so-called Triple I. Simultaneously, different feedstocks for biodiesel production were investigated, including Vernicia montana, Hibiscus sabdariffa, and Pongamia pinnata followed by the application of four biodiesel blend systems, which are B5, B10, B20, and B100. Subsequently, the influence of various changes in, for instance, crop yield, fuel price, distribution distance, coproduct prices, biodiesel production technology was also discussed. Findings of this study were used to propose feasible options and implications for biodiesel policies toward sustainable development of inedible vegetable oil-based biodiesel in Northern Viet Nam.

The costs associated with the production of biodiesel fuel (BDF) are directly affected by the nature of the feedstock material and the methods used during the production process. In Southeast Asia, many non-edible oils are used to produce BDFs, as exemplified by the recent use of the non-edible oil derived fromVernicia montanaLour. in Laos and Vietnam for the production of BDF. In this work, we developed an improved procedure for the production of BDF fromVernicia montanaoil consisting of 80.3%±0.5% α-eleostearic acid moiety (C18:3) using a co-solvent method. Furthermore, the stability of the BDF was evaluated based on its iodine value and unsaturated ester content. The optimized production conditions were determined to be as follows: methanol/oil molar ratio of 6:1, 1% (wt/wt) KOH, 20% (wt/wt) acetone as a co-solvent, and a reaction temperature of 40°C. Under these conditions, we achieved a BDF conversion efficiency of 99%±0.3% within 30 min of initiating the transesterification process. Notably, the BDF produced fromVernicia montanaoil showed good stability to air at temperatures ≤30°C for 1 month, showing similar stability properties to the BDF produced from rapeseed oil.

Candlenut oil (CNO) is a potentially new feedstock for biodiesel (BDF) production. In this paper, a two-step co-solvent method for BDF production from CNO was examined. Firstly, esterification of free fatty acids (FFAs) (7 wt%) present in CNO was carried out using a co-solvent of acetonitrile (30 wt%) and H2SO4 as a catalyst. The content of FFAs was reduced to 0.8 wt% in 1 h at 65°C. Subsequent transesterification of the crude oil produced was carried out using a co-solvent of acetone (20 wt%) and 1 wt% potassium hydroxide (KOH). Ester content of 99.3% was obtained at 40°C in 45 min. The water content in BDF was 0.023% upon purification using vacuum distillation at 5 kPa. The components of CNO BDF were characterized using a Fourier-transform infrared spectrometry and gas chromatography-flame ionization detector. The physicochemical properties of BDF satisfied the ASTM D6751-02 standard. The gaseous exhaust emissions from the diesel engine upon combustion of the BDF blends (B0-B100) with petrodiesel were examined. The emissions of carbon monoxide and hydrocarbons were clearly lower, but that of nitrogen oxides was higher in comparison to those from petro-diesel.

This paper is the second part of a two-paper series on framework development and application demonstration of the Inclusive Impact Index (Triple I), a single-index of sustainability assessment. This Part II aims to exemplify findings obtained from Part I, which developed a full-scale framework for estimation of Triple I, based on the current context of life cycle sustainability assessment. The entire life cycle of inedible vegetable oil-derived biodiesel production and use in cruise ships in Ha Long Bay, was used as a case study for the demonstration. Furthermore, this paper also examines the sustainable potential of several blends of Hibiscus sabdariffa L. (Roselle) and Vernicia montana L. (Trau) biodiesel. Consequently, implications for sustainable biodiesel policies in Quang Ninh Province have been introduced. Under Triple I, the sustainable potential of different biodiesel systems in Ha Long Bay was examined with respect to impacts on ecological footprint, biocapacity, ecosystem quality, human health and the economy. Several biodiesel-petroleum diesel blends were considered in this paper involving B5 (5% by volume (vol%) biodiesel), B10 (10 vol% biodiesel), B20 (20 vol% biodiesel) and B100 (neat biodiesel). Triple I gages the sustainability of all biodiesel blends as alternatives to petroleum diesel. The findings suggest that the application of B10 and B20 blends are most appropriate, as they were the most stable and equivalent in terms of economic, environmental and social impacts, particularly in the case of B20. Since B100 has considerably high sustainable potential but longer Triple I payback time compared to the three lower blends, this study proposes a consideration of B20 and B10 for short-term and B100 for long-term biodiesel application pathways. Results of Triple I are in line with previous studies, and this confirms the precision of Triple I as a sustainability assessment index. On the other hand, by quantitatively revealing what and how an individual factor and its changes can affect the sustainability of a biodiesel system, Triple I has proved its superiority to other indexes. Nevertheless, due to the absence of social impacts in the Triple I estimation, this study recommended for a further development of the Triple I framework to contemplate evaluating social aspects.

12-Deoxy-13,16-dioxy phorbol esters (PEs) are bio-active and highly toxic compounds that can be found in the seed oil of the Jatropha curcas Linnaeus (JCL) plant. In this report, the photodegradation behaviors of PEs and an isolated J2 component were examined under UV/Vis 254–575nm irradiation (power 0.4–120 W/m2) and natural sunlight (maximum power of 800–1100 W/m2) in aqueous solution. The J2 was selectively degraded when it was irradiated with UV254–280nm. The photodegradation of the PEs occurred with first order kinetics, and the rate constants of J2 and PEs under UV254nm irradiation were 1.78 × 10−2 and 2.41 × 10−3 s−1, respectively. The rate constant of the PEs under natural sunlight was 1.37 × 10−3 s−1. Characterization by high performance liquid chromatography/tandem mass spectrometry revealed that the degradation process was preceded by the isomerization of the conjugated unsaturated diester group of the PEs, followed by disruption of the phorbol skeleton. These results indicate that PEs can be selectively degraded in aqueous solution by UV254–280nm and/or Vis545–575nm irradiation. The aqueous waste streams contaminated with PEs that are generated during biodiesel production could therefore be detoxified by degradation under UV254nm light and natural sunlight.

Direct chemiluminescence emission from the reaction of acidic permanganate and organic compounds was employed for determining the chemical oxygen demand (COD) in water (1-step CL COD). Due to the diversity of organic pollutants in water, there are no standards for COD measurements, and many compounds do not show any chemiluminescence signal in the 1-step CL COD method. As a result, this method shows a low correlation with the conventional CODMn method. In this study, a new 3-step CL COD method was developed to overcome these drawbacks. The basic principle of the 3-step CL COD method is based on the principle of "back titration" in the CODMn method: (i) the sample is treated with permanganate under heating, (ii) the excess permanganate is treated with pyrogallol, and (iii) the excess pyrogallol is measured by the chemiluminescence reaction with permanganate. The reagent concentration, sample volume, and heating temperature were optimized, and the 3-step CL COD method successfully obtained the signal from some samples that cannot be detected by 1-step CL COD method. The calibration graph is linear in the range of 0 - 12.86 mg/L with a detection limit of 0.082 mg/L. This method is continuous, sensitive and low cost compared with the conventional method, and is applicable for on-site monitoring. The effect of the chloride ion was investigated, and showed an insignificant effect after two-times dilution of high-salinity samples. The correlation with the CODMn method for various organic compounds showed a good coefficient of determination, R2 = 0.9773 (n = 16).

Alkaline treatment (Alk) combined with ultrasound-assisted extraction (UAE) (Alk+UAE) was examined as a means of extracting tocols and γ-oryzanol from rice bran into an organic phase while simultaneously recovering ferulic acid into an aqueous phase. The tocols and γ-oryzanol/ferulic acid yields were determined using high-performance liquid chromatography with fluorescence and UV detection. The effects of extraction conditions were evaluated by varying the Alk treatment temperature and extraction duration. The maximum yields of tocols and γ-oryzanol were obtained at 25 °C over a time span of 30 min. When the temperature was increased to 80 °C, the yield of ferulic acid increased dramatically, whereas the recovery of γ-oryzanol slightly decreased. Employing the Alk+UAE procedure, the recovered concentrations of tocols, γ-oryzanol, and ferulic acid were in the ranges of 146-518, 1591-3629, and 352-970 μg/g, respectively. These results are in good agreement with those reported for rice bran samples from Thailand.

In this study, the use of potassium dichromate as an oxidizing reagent in the 3-step chemiluminescence (CL) chemical oxygen demand (COD) method, based on the principle of the permanganate COD (CODMn) method (JIS K0102), was developed (3-step CL CODCr method). The sample reacted with an excess of dichromate under heating, and the remaining dichromate was neutralized by a reducing organic compound. Then, the remaining amount of the reducing organic compound was detected in the CL detector using permanganate CL reagent. Six organic compounds – gallic acid, phenol, pyrocatechol, ascorbic acid, pyrogallol, and potassium hydrogen phthalate – were investigated as the reducing organic compounds. The CL kinetics of these compounds with acidic permanganate reagent were studied, and pyrogallol showed the highest signal with the fastest relevant response. Hence, pyrogallol was chosen as the reducing organic compound. The enhancement effects of seven metal ions – Cr(III), Mn(II), Cu(II), Ag(I), Fe(II), Fe(III), and Mg(II) – were investigated. The results showed that Cr(III), Mn(II), Fe(II), and Fe(III) enhanced the signal. Fe(II) and Fe(III) showed the highest enhancement effects, in which the signals increased to 188% and 205%, respectively. However, Fe(II) made the permanganate reagent become less stable due to the reaction between Fe(II) and permanganate and the enhancement decreased significantly with time. Hence, Fe(III) was added to the permanganate reagent at the optimum concentration of 0.45 mmol dm−3. The correlation between the 3-step CL CODCr method and the conventional CODMn for several organic compounds showed a good determination coefficient R2 = 0.9594 (n = 16). The limit of detection was 0.083 mg L−1, using gallic acid as a standard. The method was applied to measurement of river water samples, obtaining results in good correlation with the CODMn method.

The consumption of fuel by vehicles emits nitrogen oxides (NOx) and non-methane hydrocarbons (NMHCs) into the atmosphere, which are important ozone precursors. Ozone is formed as a secondary pollutant via photochemical processes and is not emitted directly into the atmosphere. In this paper, the ozone increase resulting from the use of biodiesel and diesel fuels was investigated, and the different ozone formation trends were experimentally evaluated. Known amounts of exhaust gas from a power generator operated using biodiesel and diesel fuels were added to ambient air. The quality of the ambient air, such as the initial NMHC and NOx concentrations, and the irradiation intensity have an effect on the ozone levels. When 30 cm(3) of biodiesel fuel exhaust gas (BFEG) or diesel fuel exhausted gas (DFEG) was added to 18 dm(3) of ambient air, the highest ratios of ozone increase from BFEG compared with DFEG in Japan and Vietnam were 31.2 and 42.8%, respectively, and the maximum ozone increases resulting from DFEG and BFEG compared with the ambient air in Japan were 17.4 and 26.4 ppb, respectively. The ozone increase resulting from the use of BFEG was large and significant compared to that from DFEG under all experimental conditions. The ozone concentration increased as the amount of added exhaust gas increased. The ozone increase from the Jatropha-BFEG was slightly higher than that from waste cooking oil-BFEG.

Concentrations of PCBs and OCPs were measured in 35 surface sediment samples collected from offshore waters of Central Vietnam. The mean concentrations of PCBs, HCHs, and DDTs in surface sediments were 86.5, 37.0, and 44.5pgg(-1), respectively. Additionally, nine PCDDs, eleven PCDFs, and twelve dl-PCBs were also examined in 19 sediment core samples collected from five locations. Concentration of PCDDs, PCDFs, and dl-PCBs ranged from 200 to 460, 0.39 to 2.9, and 1.6 to 22pgg(-1), respectively. OCDD was detected at the highest concentration, ranged from 100 to 300pgg(-1). Generally, the concentrations of PCDD/Fs at shallower depths were higher, meanwhile the depth profiles of dl-PCBs in sediment cores were different than the depth profiles of PCDD/Fs. The results suggest that the pollution of PCBs might be from many different sources leading to the variation between depths.

Biodiesel fuel (BDF) is an important alternative fuel because of the carbon neutral nature of biomass and the exhaustion of fossil fuel resources. Jatropha curcas oil (JCO) produced from J. curcas seeds contains toxic phorbol esters that can cause cancer. The behaviors of toxic phorbol esters were investigated during BDF production. Liquid chromatography–tandem mass spectrometry and photodiode array analyses revealed that the phorbol esters contained in JCO had a tigliane skeleton. The partition coefficients of phorbol esters between methanol (MeOH) and the oil (KMeOH/oil) ranged from 2.4 to 20. As a result, the phorbol esters in the JCO were largely partitioned into the MeOH phase. The phorbol esters in the oil were converted stoichiometrically into phorbol and the corresponding fatty acid methyl esters via a transesterification reaction in a potassium hydroxide (KOH)/methanol (MeOH) solution. The phorbol produced predominantly partitioned into the glycerin phase. A small amount of phorbol residue contained in the BDF could be removed by washing with water. These results suggest that it is safe to use BDF produced by the aforementioned transesterification reaction and purification process. However, phorbol contamination of glycerin and wastewater from the production process should not be ignored.

Low molecular weight-methyl ester (LMW-ME), which was reported in our previous study [1], was generated by the use of biodiesel fuel (BDF) with a diesel power generator. In this article, the detailed chemical kinetics for the thermal decomposition of LMW-MEs was investigated at atmospheric pressure and a temperature range of 773 to 973 K. Six standards of LMW-MEs were used for thermal decomposition in a continuous flow reactor. The kinetic data, such as reaction orders, activation energies, and rate constants, were then calculated. The reaction orders and activation energies of the thermal decomposition reactions of C4, C5, C6, C7, C8, and C9 were 1.13, 0.96, 1.17, 0.80, 0.99, 0.84, and 312.04, 117.37, 87.29, 62.94, 74.80, 75.79 kJ mol−1, respectively. The decomposition of LMW-MEs with higher carbon numbers was faster than those with smaller carbon numbers, except for C8. The C4 methyl ester was stable and abundant in the product of the decomposition as well as in the exhausted gas from the engine combustion using BDF. This kinetic data will be applied to modeling study on BDF decomposition and engine technologies to mitigate toxic emissions from BDF combustion. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1190–1197, 2016

A method for producing ferulic acid by ultrasound-assisted, homogeneous, base-catalyzed hydrolysis of γ-oryzanol was developed. Experiments were conducted using various reaction temperatures and ratios of γ-oryzanol to base catalyst in both homogeneous and heterogeneous systems. The reaction performed without ultrasound under the homogeneous conditions of potassium hydroxide/γ-oryzanol ratio (wt/wt) 20 : 1 and 75°C gave a ferulic acid yield of 83.3% in 3 h. Acceleration of the homogeneous reaction using ultrasound irradiation at 20 (horn type) and 200 kHz (planar type) was explored by evaluating the kinetic parameters. At 30°C, the ratios of ultrasonic irradiation at low (20 kHz, 50 W) and high (200 kHz, 50 W) frequencies versus those of the heating method increased by 2.0- and 1.4-fold in comparison with those at 60°C, respectively. The contribution of ultrasonic irradiation (50 W) to the hydrolysis reaction decreased with increase of temperature. However, irradiation at 20 kHz and a power of 180 W gave a 94% ferulic acid yield at 60°C in 3 h. These results indicate that the use of low frequency (horn type and high-power irradiation) enabled yields higher than 90% to be obtained.

Pharmaceutical residues in fresh water bodies are of significant environmental concern due to their undesirable effects on aquatic organisms at very low concentrations. The present study is about the elimination and overall degradation of a common anti-inflammatory pharmaceutical-paracetamol (PCT) in water by catalytic oxidation using high-frequency ultrasound, UV-irradiation (254 nm) and both. The catalysts were synthesized sonolytically by the reduction of Pd and Au to the zero-valent state followed by immobilization of the nanoparticles on the surface of commercial TiO 2 (P-25) to improve the activity of the semiconductor under ultrasonic and UV irradiation. It was found that sonolytic oxidation of PCT during catalysis with Pd–TiO 2 and Pd/Au–TiO 2 was very effective owing to the significantly smaller size of these particles (than that of Au–TiO 2 ), which promoted the formation and collapse of cavitation bubbles on their surface and the incidence of solute contact with the active sites. The addition of persulfate further enhanced the rate of PCT decay, signifying the role of ultrasound in activating the reagent and that of radical-initiated oxidation reactions in the decomposition of the parent compound. The activity of P-25 was low and almost equal under sonolysis and photolysis, but considerably higher under sono-photolysis, where the unfavorable properties of the semiconductor were minimized via combined effects of the two processes. Hybridization also induced a considerable synergy in carbon-mineralization, which was relatively low with single processes. The results were attributed to minimization of electron-hole pair recombination, surface corrosion and competition for photons and radical species. Au-supported particles exhibited higher activity in the presence of UV-irradiation than ultrasound, which was attributed to the unique activity of gold in the UV–vis region. Finally, Pd–TiO 2 was found to be the most stable nanocomposite in terms of the ease of recovery and the efficiency of reuse.

Phorbol esters (PEs) are highly toxic compounds that cause skin irritation, inflammation, and tumor promotion upon contact with humans or animals. These compounds are naturally present in Jatropha curcas L. To promote the use of J. curcas seed oil in bio-diesel production industries and reduce environmental concerns, it is necessary to find methods of degrading PEs. In this study, the degradation of phorbol 12,13-diacetate (PDA), as a representative PE, in aqueous solution at a concentration of 10 mg/L by 60Co-γ-irradiation was investigated. The results demonstrate that PDA was effectively degraded by this treatment and the degradation efficiency increased with the absorbed dose within the range of 0.5–3 kGy. Complete degradation of PDA was achieved at a dose of 3 kGy. In the presence of radical scavengers (i.e., methanol, tert-butanol, 2-propanol), reactive species from water radiolysis were scavenged, and significant inhibition of PDA degradation was observed at absorbed doses less than 1 kGy. In the presence of nitrous oxide, the generation of hydroxyl radicals ( OH) was promoted during gamma irradiation and PDA degradation was drastically enhanced.

Ferulic acid (FA) is widely used as an antioxidant, e.g., as a Ultraviolet (UV) protectant in cosmetics and in various medical applications. It has been produced by the hydrolysis of γ-oryzanol found in rice bran oil soapstock. In this study, the base-catalyzed, homogenous hydrolysis of γ-oryzanol was conducted using various ratios of potassium hydroxide (KOH) to γ-oryzanol, initial concentrations of γ-oryzanol in the reaction mixture, and ratios of ethanol (EtOH) (as cosolvent)/ethyl acetate (EtOAc) (γ-oryzanol solution). Acceleration of the reaction using a planar type of ultrasound sonicator (78 and 130 kHz) at different reaction temperatures was explored. By using a heating method, the 80% yield of FA was attained at 75 °C in 4 h under homogeneous conditions (initial concentration of γ-oryzanol 12 mg/mL, the KOH/γ-oryzanol ratio (wt/wt) 10/1, and EtOH/EtOAc ratio (v/v) 5/1). With the assistance of 78 and 130 kHz irradiation, the yields reached 90%. The heating method was applied for the γ-oryzanol-containing extract prepared from rice bran oil soapstock. From soapstock, the 74.3% yield of FA was obtained, but 20% of the trans-FA in the reaction mixture was transformed into cis-form within one month.

In this study, we studied the production of biodiesel from waste cooking oil with co-solvent technology. A co-solvent technology with acetone has many advantage, but needs to remove solvents dissolved in the mixture. The optimum transesterification conditions to obtain the 98% purity of fatty acid methyl esters (FAMEs) are as follows: 1 wt.% potassium hydroxide catalyst, 20 wt.% acetone and 5:1 methanol to oil molar ratio, reaction temperature of 40 0 C and reaction time of 30 minutes. The water content is 104 ppm, methanol content in the final product 95 ppm, and the concentration of acetone in the products 247 ppm.

b National University of Laos, Vientiane Capital, 7322, Lao PDR ABSTRACT: In this study, we examine the degradation of phorbol esters with atmospheric pres- sure plasma and, in particular, the highly tolerant phorbol 12-myristate 13-acetate (PMA) mole- cule. We determined the degradation mechanism by analyzing the structural information of the by-product obtained using mass spectrometry. The plasma source was also improved to generate more active radicals, thereby enhancing the degradation of PMA.

An homogeneous reaction process using acetone as a co-solvent for the transesterification of vegetable oils with methanol in the presence of potassium hydroxide catalyst has been developed. The effects of the main parameters, such as the amounts of acetone and KOH, the molar ratio of methanol to oil and the reaction temperature, on fatty acid methyl esters (FAME) yield were investigated. The optimal conditions were: 25 wt.% acetone and 1.0 wt.% KOH catalyst in oil; a molar ratio of methanol to oil of 4.5: 1; and a reaction temperature of 25 degrees C. Under these conditions, the conversion of vegetable oil to FAME exceeded 98% after 30 min. This method was applied to produce biodiesel fuel (BDF) from waste cooking oil (WCO), canola, catfish and Jatropha curcas oils, with the main product quality factors satisfying the JIS 2390 BDF standards. (C) 2012 Elsevier Ltd. All rights reserved.

Phorbol esters (PEs) are well known as the main toxic compounds in Jatropha curcas Linnaeus (JCL), the seed oil of which has been considered as a major feedstock for the production of biodiesel. In the present study, we investigated a series of PEs extracted from JCL seed kernels with methanol (MeOH), and identified more than seven components contained in the PEs. The isolation of main five components of a series of PEs was revised using a semi-preparative reversed phase HPLC analysis of ODS-3 column. The five peaks of components were successfully isolated, and peaks of J2, J3, J5, and J7 were assigned to be Jatropha factors C1, C2, C3, and C4/5, but J6 was a mixture of Jatropha factor C6 and its isomer based on the data of UV and LC-MS/MS, and J2 was identified using 1H NMR analysis. By characterization using LC-MS/MS analysis, all components of a series of PEs were elucidated to be the 12-deoxy-16-hydroxyphorbol esters composed of isomeric form of dicarboxylic groups with same m/z value of 380.

More than 10 million tons of biodiesel fuel (BDF) have been produced in the world from the transesterification of vegetable oil with methanol by using acid catalysts (sulfuric acid, H2SO4), alkaline catalysts (sodium hydroxide, NaOH or potassium hydroxide, KOH), solid catalysts and enzymes. Unfortunately, the price of BDF is still more expensive than that of petro diesel fuel due to the lack of a suitable raw material oil. Here, we review the best selection of BDF production systems including raw materials, catalysts and production technologies. In addition, glycerol formed as a by-product needs to be converted to useful chemicals to reduce the amount of glycerol waste. With this in mind, we have also reviewed some recent studies on the utilization of glycerol.

The levels of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) were determined in sediment samples from Can Gio, South Vietnam, and Osaka, Japan. Can Gio is known for the defoliation of its mangrove forests by aerial spraying with Agent Orange during the Vietnam War, whereas Osaka is renowned for a PCDD/PCDF pollution accident at a municipal solid-waste incinerator. For comparison, we also analyzed PCDD/PCDFs and DL-PCBs in sediment samples from Hue and Hanoi, Vietnam. The toxic equivalent quantity (TEQ) values in Can Gio were as high as those in Hue, Hanoi, and suburban areas of Osaka, but much lower than those in urban areas of Osaka. The proportion of the World Health Organization (WHO)-TEQ value contributed by 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) in Can Gio was approximately 30%, higher than the values in the other sample areas. These data suggest that residual sedimentary TCDD that originated from aerial spraying of Agent Orange occur in only low concentrations in Can Gio. The main contributors to WHO-TEQ values in Can Gio are natural sources, as in Hue. In contrast, commercial PCBs are the dominant contributors to WHO-TEQ values in Hanoi. In Osaka, agrochemicals used in rice cultivation, the incineration of solid waste, and commercial PCBs equally contributed to WHO-TEQ values at suburban locations. The dumping of incinerator-related materials and/or the inadequate management of commercial PCBs have resulted in significantly elevated WHO-TEQ values of 240–370 ng kg–1 dw at urban locations in Osaka.

Production of fatty acid ethyl ester (FAEE) from oleic acid (FFA) with short-chain alcohols (ethanol, propanol, and butanol) under ultrasonic irradiation was investigated in this work. Batch esterification of oleic acid was carried out to study the effect of: test temperatures of 10–60 °C, molar ratios of alcohol to oleic acid of 1:1–10:1, quantity of catalysts of 0.5–10% (wt of sulfuric acid/wt of oleic acid) and irradiation times of 10 h. The optimum condition for the esterification process was molar ratio of alcohol to oleic acid at 3:1 with 5 wt% of H2SO4 at 60 °C with an irradiation time of 2 h.

Chemical effects of ultrasound have been actively researched in the field of the synthesis of various metal nanoparticles and nanostructured materials. It is very important to understand the reduction mechanism of metal ions, because the reduction processes can be often applied to the synthesis of various materials. In this study, the sonochemical reduction of MnO4- to MnO2 in water under Ar atmosphere was investigated to discuss the reduction mechanism. It has been reported that H, OH, H2 and H2O2 are formed from the sonolysis of water. To understand the roles of H2O2 on the reduction, the reaction of MnO4- with H2O2 without ultrasonic irradiation was investigated. The obtained results suggested the progress of the following reaction: 2MnO4-+3H2O2-->2MnO2+3O2+2OH-+2H2O. In addition, the rates of the sonochemical reduction of MnO4- were investigated in the presence of 1-propanol, where 1-propanol acted as an OH radical scavenger so that the amounts of the sonochemically formed H2O2 molecules were able to be controlled. The results clearly indicated that the sonochemically formed H2O2 molecules as well as H2 molecules and H atoms play an important role for MnO4- reduction. This mechanism was also supported by the analysis of pH changes during ultrasonic irradiation: the pH value increased as the sonochemical reduction of MnO4- proceeded.

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM) with a diameter

Ethanol was enriched by ultrasonic atomization. Enrichment ratios were increased by adding salt to the ethanol solution. Different enrichment ratios were observed for different types of salts in a range of low ethanol concentrations. The enrichment ratio was significantly improved by adding K 2 CO 3 or (NH 4 ) 2 SO 4 . It is concluded that this is due to enhanced interfacial adsorption of the ethanol. Addition of Na 2 CO 3 to the ethanol solution also enhanced the interfacial adsorption of the ethanol, but the effect was relatively small. Addition of NaCl to the ethanol solution did not enhance the interfacial adsorption of the ethanol.

Volatile acidic solutes were used to make dilute solutions, which were frozen by various methods. The concentration of solutes and the pH of the samples were measured before and after being frozen. When the sample solution is frozen from the bottom to the top, solutes are concentrated into the unfrozen solution (i.e., the upper part of the sample) due to the freeze concentration effect. Thereafter, concentrated anions combine with protons to form acids, and the amount of acids in the unfrozen solution increase as the ice formation progresses. At the end of freezing, the acid is saturated at the ice surface, and if the formed acid is volatile, then evaporation occurs. Frozen solutions were allowed to stand below 0 °C, where evaporation rates were obtained in the following order: formate > acetate > propionate > n-butyrate > chloride . nitrate. Except for nitrate, evaporation rates were enough to take place in frozen water of the natural environment (e.g., ice crystal, graupel, snow crystal, and frozen droplets). The relationship between the evaporation rate of volatile acids and their physical properties demonstrate that the evaporation rates of weak acids are faster than those of strong acids, and the evaporation rates among weak acids are the same as the volatility of weak acids.

The degradation of hydrazine (N2H4) with concentrations of 0.1–5.0 mmol/L was investigated as a function of amount of coal ash (0.0–5.0 wt%) under the stirring (300 rpm) and ultrasonic irradiation (200 kHz, 200 W) conditions. It was found that the rate of decrease in the hydrazine concentration depended upon an amount of coal ash under the stirring and ultrasonic irradiation condition. It was considered under the stirring condition that hydrazine was adsorbed and degraded partly on coal ash. Furthermore, the sonochemically formed OH radicals were more effective in the hydrazine degradation than stirring condition in the presence of an intermediate amount of coal ash (0.6–2.4 wt%), whereas the effect of OH radicals disappeared in the presence of coal ash more than 2.4 wt%.

Methanolysis of triolein was investigated at room temperature by 40 kHz ultrasonic irradiation to make biodiesel fuel as methyl esters. It was found that the yield of methyl esters strongly depended on the amount of KOH and the molar ratio of methanol to triolein (M/T) and was highest at the M/T molar ratio of 6/1, KOH concentration of 1 wt% and irradiation time of 30 min. In addition, the effects of sonication on the methanolysis of triolein were discussed in comparison to the effects of stirring experiments. The optimum condition under stirring experiments showed that the molar ratio of M/T, KOH concentration and reaction time were 6/1, 1.5 wt% and 4 h, respectively. These results clearly indicated that the ultrasonic irradiation method would be a promising one compared to the conventional stirring method. The high yield under the ultrasonic irradiation condition would be due to high speed mixing and mass transfer between the methanol and triolein as well as the formation of a microemulsion resulting from the ultrasonic cavitation phenomenon.