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In recent years, significant attention has been dedicated to converting biomass carbohydrates into alkyl levulinates (biofuel additives) in alcoholic media, in search of various cheap and active solid catalysts through relatively easy pathways and from non-dangerous precursors. The synthesis of methyl levulinate (ML) using a new Bronsted/Lewis acid sites catalyst was investigated, emphasizing the influence of three parameters (catalyst loading, the molar concentration of fructose in methanol, and reaction temperature) on the process. The synthetized catalyst, SO42−/TiO2–La2O3 coating Fe3O4, was characterized by different techniques (FT-IR, XRD, TGA, TEM-EDX, ICP-OES). The design of the ML synthesis experiment was carried out using the Box-Behnken technique, while the response surface methodology was applied to obtain the optimized process conditions. A mathematical model of the catalytic synthesis was built, based upon first principles, and the experimental time variation of the reaction mixture concentrations was used to find, through regression, the values of the constants of a newly proposed kinetic model.

Fish oils with a high content of polyunsaturated fatty acids (PUFAs) are gaining increasing interest in the food and nutraceutical industry, due to their important functional properties for human beings� health improvement. The most important PUFAs have at least two double bonds placed on the carbon chain. These include ?-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahaxaneoic acid (DHA). Microencapsulation is a technique used to protect the bioactive compounds from oxidative damage, to ensure their controlled release and to activate the synergistic effect of the ingredients, if it exists. In this context, the microencapsulation process of fish oils rich in PUFAs using alginate was studied, in the presence and the absence of an ultrasonic (US) field. Both BoxBehnken design of experiment technique and the Response Surface Method were used, to investigate the influence of the process parameters and to optimize the operating conditions. The operating parameters under investigation were the sodium alginate to fish oil ratio, the calcium chloride concentration and time being the objective. The fish oil microspheres had a homogeneous round shape, a diameter of 0.12 � 0.02 mm. Physicochemical description of microcapsules was performed using modern characterization methods.

The presence of nitrate concentration in drinking water can cause high toxicity to the human body, being considered among the most important pollutant in the environment. Among the many methods available such as biological treatment, electrodialysis, reverse osmosis, adsorption, ion exchange, adsorption is the most used technique due to its low cost and simplistic design. Therefore, the aim of this paper was to study the retention of nitrate anion from high concentration aqueous solutions on a novel magnetic adsorbent obtained by pyrolysis of de-oiled microalgal biomass. The prepared adsorbent was characterized by textural analysis (specific surface area, pore volume, average pore diameter, pore size distribution), FT-IR and TGA techniques. The influence of nitrate concentration, pH, retention time and adsorbent mass were evaluated. The equilibrium adsorption data were fitted to three isotherms, namely Langmuir, Freundlich and Temkin. The equilibrium isotherms indicate a pH-dependent behavior, characterized by Temkin model at pH=7 and Freundlich model at pH = 9, respectively. In order to estimate the nitrate removal efficiency multiple linear regressions and artificial neural networks were investigated.

Biomass is one of the most important renewable energy resources to produce sustainable liquid fuel. This study presents the process of hydrodeoxygenation/hydrocracking on a model of oxygenated compounds such as fatty acid methyl esters using a bifunctional catalyst that contains a metallic function based on copper and palladium and an acid function type ZMS-5. Hydrocracking of methyl esters on the bifunctional catalyst CuPd/γ-Al2O3–ZSM-5 realized on a fix bed reactor led to obtaining of n-alkanes, iso-alkanes, saturated and aromatic cyclic hydrocarbons with 9 to 18 carbon atoms. The conversion reach 100% value at temperature higher than 350 °C. The yield in n-alkanes varies with a maximum at temperature of 325 °C, meanwhile, the yield in iso-alkanes remains approx. constant. The cyclization and aromatization reactions are favored at temperatures higher than 350 °C.

Fir sawdust was employed for the preparation of activated carbons by potassium hydroxide (KOH), phosphoric acid (H3PO4) and zinc chloride (ZnCl2) activations. The three adsorbents have been abbreviated BAC, AAC and SAC. The nitrogen adsorption–desorption experiments were performed at 77 K to determine the physical surface properties of these three adsorbents. The chemical properties were depicted by the point of zero charge (pHPZC) measurement and by Fourier Transform Infrared (FTIR) spectra. Characterization of the fir sawdust activated carbons suggests that their structures are highly dependent on the activation agent molecules. In this research, in order to evaluate the performances of the fir sawdust activated carbons, a series of batch experiments were conducted for the adsorption of p-nitrophenol from aqueous solution at initial concentrations in range of 50–250 mg/L. The equilibrium data were fitted by non linear regression with two-parameter models: Langmuir, Freundlich and Jovanovic and three-parameter models: Redlich–Peterson, Vieth–Sladek, Koble–Corrigan and Brouers–Sotolongo. Five error functions were used to compare the accuracy of the fit. The equilibrium data of p-nitrophenol onto BAC were better described by Langmuir isotherm and by Freundlich isotherm for AAC and SAC. The maximum adsorption capacity of p-nitrophenol was found for SAC (qm = 318.67 mg/g) and this can be attributed to the basic nitrogen-containing groups and graphitic structure. The results proved that zinc chloride-activated carbon was a successful adsorbent for p-nitrophenol removal from wastewater.

This study presents the catalytic pyrolysis of conditioned digestate from anaerobic digestion co-digestion plants, in the presence of WO3/γ-Al2O3 catalyst under nitrogen atmosphere. The experimental program was performed at atmospheric pressure, temperature in the isothermal reaction zone 425 °C and feeding flow rate of 0.33 mL/min. The analysis of bio-oil composition suggested the presence of a large number of linear and branched aliphatic hydrocarbon components, alcohols, phenols and alkyl aromatic hydrocarbons with two or three methyl-type substituents. The major components present in the cracking gas are methane and carbon oxide. The simulation data obtained for compression at equilibrium of cracking gas indicates an olefin content of LPG higher than the values imposed in the technical specifications of similar products on the market.

In this study, the SO42-/TiO2-La2O3-Fe2O3 catalyst was prepared and tested in the conversion of fructose to ethyl levulinate . The catalyst was characterized from the point of view of the textural analysis, FT-IR analysis, acid strength distribution, X-ray powder diffraction and pyridine adsorption IR spectra. The influence of the reaction parameters on the ethyl levulinate yield was study. The maximum yield of 37.95% in levulinate esters was obtained at 180 �C, 2 g catalyst and 4 h reaction time. The effect of ethyl levulinate addition to diesel-biodiesel blend in different rates, i.e, 0.5, 1, 2.5, 5 (w.t %) on density, kinematic viscosity and flash point was evaluated and compared with the European specification.

An attractive solution for improvement of pyrolysis bio-oil composition regarding the high content of oxygenated compounds is catalytic upgrading via hydrotreating process. The objective of this work is to evaluate the catalytic activity of CoMo /γ-Al2O3-HMS in bio-oil hydrotreating. The catalyst was characterized by surface area, X-ray diffraction (XRD), TEM, FT-IR and XPS analysis. The experiments were carried out in a flow fixed-bed reactor at the temperature range of 250-320 oC, pressure between 20-40 bar, and LHSV 3h-1. The results showed that increased temperature and pressure favors the hydrodeoxygenation process, reaching the maxim bio-oil conversion of 87.23%. Also, a chemical modelling algorithm was developed in order to evaluate the harmful emissions resulted from hydrotreating gaseous phase combustion. This calculation algorithm can be applied to any pressurized or atmospheric combustion engine fueled with different mixture of combustible gases such as: natural gas, hydrogen-enriched natural gas and oxy-fuel.

Polyunsaturated fatty acids (PUFA) have a preventive effect on high blood pressure. [...]

Glycerol acetals/ketals and their esters, produced from renewable raw materials, are highly valuable compounds, being used as oxygenated fuel additives and ecological solvents. A new method for obtaining glycerol acetal/ketal esters, difficult to synthesize using classical techniques, was developed. This method is based on the reversible reaction of 1,2-O-isopropylidene-glycerol esters (IPGEs) obtained from glycerin, by-product from biodiesel production, with low volatility aldehydes/ketones (e.g. furfural and ethyl levulinate, both obtained from lignocellulosic biomass), in the presence of a heterogeneous acid catalyst. To circumvent reaching equilibrium, the continuous removal of acetone (Ac) from the reaction mixture was done, the former being reused in the synthesis of IPGEs. The method viability was assessed by synthesis and characterization of eight new compounds from two classes: furfurylideneglycerol esters (FGEs) and ethyl levulinate glycerol ketal esters (ELGKEs). A detailed kinetic study was done throughout an experimental program, first developed in Asia 330, a modular range flow chemistry system, then in a continuous-flow process at micropilot scale.

The purpose of this study was to develop a method for rapid quantitative and qualitative determination of the oil from microalgae lipid fraction obtained from Nannochloris sp biomass. The lipid fraction was first refluxed with 4% KOH in MeOH (60, 90, 120 min), followed by reaction with 20% BF3 in MeOH, using different times of reflux (90,120, 150 min) for each time of reflux with 4% KOH in MeOH. The FAME samples were analyzed by GC-MS analysis. 120 min reflux with 4% KOH in MeOH, 90 min with 20% BF3 in MeOH and a ratio lipid fraction: 4% KOH in MeOH: 20% BF3 in MeOH=1:20:27, were required to obtain the higher percent of oil in the microalgae lipid fraction. The relevance of the method developed was proved by TGA analysis and by transesterification of a sunflower oil sample in the same conditions.

In human diet, polyunsaturated fatty acids (PUFA), have an essential role in optimal brain functions and stroke prevention, specially, omega-3 fatty acids, e.g., 9,12,15-linolenic acid (ALA, 18:3), 5,8,11,14,17-eicosapentaenoic acid (EPA, 20:5), and 4,7,10,13,16,19-docosahexaenoic acid (DHA, 22:6). [...]

Intermediates for synthetic paraffinic kerosene with structures of fatty acid methyl ester (FAME), were synthesized from algal oil extracted from Nannochloris sp. biomass. Microalgae were grown under mixotrophic conditions to improve biomass production, using glycerin as additional source of organic carbon, by-product in FAME obtaining process. Microalgae were supplementary stressed to increase the lipid productivity, by reducing the inorganic nitrogen and partially replacing it with organic nitrogen (hydrolyzed proteins from the same microalgae). Since algal oil has high free fatty acids (FFA) content, a two-step process for FAME synthesis was necessary. In the first step, FFA was esterified with methanol over SO 4 2− /TiO 2 –La 2 O 3 solid acid catalyst. The second step, i.e. methanolysis of pre-treated oil, was performed over Na 2 SiO 3 /Mg–Al-hydrotalcite (Na 2 SiO 3 /Mg–Al-HTC) heterogeneous base catalyst. The Na 2 SiO 3 /Mg–Al-HTC catalyst was synthesized and then characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), textural analysis (BET method), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence analysis (EDXRF) and Fourier transform infrared (FTIR) spectroscopy. The influences of catalyst loading and stability, methanol-to-oil molar ratio and the reaction time on the FAME yield were carefully studied. FAME producing technology was investigated first in batch and then in a continuous flow process.

The present work investigates the possibility of using two glycerol derivatives as additives for diesel fuel. The first additive was obtained by catalytic condensation of glycerol with butane-2-one over solid superacid SO 4 2 − /TiO 2 -La 2 O 3 , while the second additive was synthesized from the first one by transesterification with methyl hexanoate. In order to investigate the chain length influence of the glycerol ketal ester over diesel properties, we studied the influence of ratio of oxygenated compound on the quality parameters of diesel fuel like viscosity, pour point, flash point and cetane index. To evaluate the effects of (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methanol and (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methyl hexanoate diesel blends on engine performance and emission characteristics, the following parameters were studied: engine power, engine torque, specific fuel consumption (sfc), nitrogen oxide (NOx), hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO 2 ) and smoke emission. All tests were carried out on a four cylinder diesel engine, without any modifications, working at full load and engine speeds between 1200 and 3700 rpm. The experimental data indicates (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methyl hexanoate as a promising additive for emission reduction (reduces HC, CO and respective smoke emission by 26.04%, 18.93% and 19.20%, respectively, and slightly increases NOx emission).

The waste resulted from fish processing industries are discarded into the environment around the world, causing environmental pollution. The main problem of fish oil extracted from waste is the high content in free fatty acids (FFA) which decrease the yield in fatty acids esters during transesterification reactions. Therefore, to correct the fish-oil properties, a new environmentally friendly heterogeneous superacid catalyst (SO42-/SnO2-ZrO2) was tested in the esterification reaction of FFA with ethanol. The catalyst was characterized by different techniques (XRD, FT-IR, FT-IR of adsorbed pyridine, BET, SEM-EDX, TGA and acidity measurements). The reaction was found to follow a Langmuir-Hinshelwood (L-H) dual-site mechanism with the novelty that both Bronsted and Lewis acid centers participate equally in the esterification reaction. The pre-treated oil was subjected to transesterification reaction with ethanol over a heterogeneous base catalyst and then, the saturated and unsaturated fractions of fatty acid ethyl esters (FAEE) were separated using a vacuum rectification unit with falling film. The saturated content can be used as biofuel, while the unsaturated FAEE are further transesterified with glycerol in order to obtain oil with high content in polyunsaturated fatty acids (PUFA). A detailed study of the intrinsic kinetic process at the surface of the superacid catalyst and a thorough mathematical model of the fixed bed reactor were written and validated by an experimental program, designed according to the D-optimal methodology.

This paper discusses the synthesis of a glycerol ketal compound obtained from condensation reaction of cyclohexanone with glycerol catalyzed by a solid superacid. The solid superacid SO42-/TiO2-La2O3 was prepared using coprecipitation and impregnation method and characterized by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy and elemental analysis. The surface acidity was measured by thermogravimetric analysis of adsorbed n-butylamine. In order to achieve the optimal reaction conditions, five impact factors: molar ratio of glycerol to cyclohexanone, catalyst calcination temperature, reaction time, catalyst amount and molar ratio of Ti/La were investigated in the experiments. Synthesized ketal compounds were analyzed by GC-MS/MS. Under the best conditions, the cyclohexanone glycerol ketal yield could reach up to 97%.

Achieving the process of pyrolysis of biomass in mild conditions is a viable option for optimizing yield in liquid products and reducing coke yield. The partially dried digestate was stabilized by suspending in a reverse emulsion containing the lipid fraction resulting from the processing of the crude digestate, a hydrophobic surfactant of the polyethoxylated castor oil type and a hydrophilic sorbitol-polyethoxylated fatty acid ester type. The pyrolysis of the digestate was carried out in a continuous system, in a quartz tubular reactor, positioned in the central area of a vertical furnace provided with an automatic temperature control system. The experimental program was performed in the presence of two catalysts, Cu and respectively polyphosphoric acid at atmospheric pressure, temperature in the isothermal reaction zone 460 oC and liquid hourly space velocity of 0.33 h-1. The composition of the liquid fractions obtained on the two catalysts differs by the presence of a higher concentration of branched isomers in the case of the polyphosphoric acid catalyst.

Salvia officinalis essential oil loaded gelatin hydrogels with improved antibacterial activity and enhanced stability was prepared by microwave-assisted polymerization method. FT-IR spectra indicated no chemical interaction between the hydrogel matrix and the essential oil functional groups. According to the swelling studies, enhanced stability in all pH media was obtained. Studying two kinetic models: Fickian transport and Schott second order kinetic model, it was demonstrated that the swelling process of the prepared hydrogels occurs after a second order kinetics. Antibacterial activity, investigated by the agar diffusion method, regarding S. aureus and E. coli is comparable to that of silver nanoparticles and twice more efficient compared to cinnamon essential oil.

This study was aimed to evaluate the growth conditions of Porphyridium purpureum and Nannochloropsis sp. microalgae for carbohydrates and lipids productivity increase. The cultivation experiments for both microalgae strains were done in triplicates using the artificial seawater (ASW) as culture media. The lipids were separated from the algal biomass and the exo-polysaccharides content from the supernatant. The results showed that the highest carbohydrate content is found in Porphyridium purpureum while the highest lipid content was found in biomass.

In this work thyme and coriander oil were encapsulated using complex coacervation microencapsulation technique.The influence of various microencapsulation parameters on encapsulation efficiency was investigated. The release characteristic of the essential oils from microcapsule was studied.

The dehydration of polysaccharides fraction in the presence of acid catalysts, is a chemical process in which results as secondary product humic matter. In our work, the humic acid mixture was for the first time based on our knowledge extracted from defatted microalgae biomass rich in polysaccharides by standard alkali treatment, followed by precipitation at acidic pH. The dried humic acid mixture has been characterized using infrared spectroscopic measurements (FT-IR). Exfoliated graphite nanoplatelets (xGnP) were used as new adsorbents for this type of humic acids mixture, their adsorption being investigated. The effect of several parameters such as: contact time, concentration of humic acid mixture, concentration of xGnP, temperature and pH of the solutions were studied. The process of adsorption took place with good results, in the following conditions: at a concentration of humic acid mixture of 18.6 mg L-1, an xGnP amount of 0.01 mg in 25 mL of solution, at a temperature of 25 �� and at acidic pH values, in aqueous solution.