Cradle-to-gate life cycle assessment of Spirulina bioplastic produced via plasticization with glycerol.

Bioplastics have been used as alternatives to conventional petroleum-based plastics to lessen the burdens on marine and terrestrial environments due to their non-biodegradability and toxicity. However, recent studies have shown that not all bioplastics may be environmentally friendly. Microalgae, such as Spirulina that do not require arable land, have been identified as a potential bioplastic source. In this study, cradle-to-gate life cycle assessment (LCA) was carried out in openLCA program using the Agribalyse database, to evaluate the environmental impacts of Spirulina bioplastic, formed from plasticization of Spirulina powder with glycerol. Two processes were created for the inventories of (i) Spirulina powder and (ii) Spirulina bioplastic, where the output of the former served as an input for the latter. The extruded bioplastic sheets were food-grade and could be used as edible packaging materials. The bioplastic was also compared to conventional plastics and it was found that the energy consumption was 3.83 ± 0.26 MJ/kg-bioplastic, which was 12% and 22% higher than that of LDPE and PVC plastic films, respectively. The impacts on the environment showed that the chemical growth medium (Zarrouk medium) and electricity were the main contributors in most of the categories. Compared to the PVC and LDPE films, the Spirulina bioplastic's impacts on the aquatic ecosystems were 2-3 times higher. The global warming potential of the Spirulina bioplastic was 1.99 ± 0.014 kg CO2 eq, which was 23% and 47% lower than that of LDPE and PVC films, respectively. Sensitivity analysis was carried out by changing the electricity source and using alternative growth media. Except for the case of switching to solar energy, the results for other cases did not differ significantly from the base case scenario. Future studies were suggested to identify different greener alternatives to the growth medium as well as different energy mixes for more environmentally benign solutions.

Thermodynamic and Kinetic Equilibrium for Adsorption of Cellulosic Xylose of Commercial Cation-Exchange Resins.

The development of low-cost purification technology is an indispensable need for industrial biorefinery. Xylose is easily obtained from hydrothermal pretreatment of lignocellulosic biomass. This current study emphasizes the chromatographic monosaccharide separation process using commercial cation-exchange resins (CER) including Amberlite 120 and Indion 225 to separate xylose from a mixture of hydrolysates. To understand the performance of the two CER, the studies of equilibrium, thermodynamics, and kinetics were evaluated. In this study, with different xylose concentrations, the adsorption equilibrium was found to follow the Freundlich isotherm model well (R2 > 0.90 for both CER). The results indicated that a pseudo-second-order model represented the xylose adsorption kinetics. In addition, the activation energy of xylose adsorption onto both CER, i.e., Amberlite 120 and Indion 225 was 34.9 and 87.1 kJ/mol, respectively. The present adsorption studies revealed the potential of these commercial CER to be employed as effective adsorbents for monosaccharide separation technology.

Techno-Economic-Environmental Analysis of Sustainable Anionic Biosurfactant Production from Palm Fatty Acid Distillate.

Currently, there is increased interest in biosurfactants as a substitute for surfactants synthesized from petroleum due to their superior properties and biodegradability. Palm oil derivatives, which can be converted to various products, were selected for biosurfactant synthesis. This paper simulated the biosurfactant production process from palm fatty acid distillate, that is, methyl ester sulfonate (MES), alkyl sulfate, alkyl phosphate, and alkyl carboxylate. Aspen Plus software was used to estimate the thermodynamic properties of intermediate aliphatic organic acids, e.g., methyl ester sulfonic acid, fatty alcohol sulfuric acid, and fatty alcohol phosphoric acid. The chemical process equipment was designed and evaluated to be used in techno-economic analysis, with comparison to petroleum source surfactant production, that is, sodium dodecylbenzenesulfonate (SDBS). The total production cost of each biosurfactant was expressed in terms of minimum selling price. The profitability of each project was determined and compared using three economic indicators: net present value (NPV), payback period, and internal rate of return (IRR). The life cycle assessment methodology was then used to evaluate the environmental impact of surfactant production. The results showed that all surfactant production processes, except for alkyl phosphate, were attractive alternatives as the project yielded a positive value of NPV. The highest NPV of 13.1 million USD was obtained from the MES production process, while the maximum IRR of 79.81% and payback period of 1.49 years were obtained from the alkyl carboxylate production process at a capacity of 1 ton/h. However, the sulfate production process caused more environmental impact than the other two surfactants (MES and carboxylate) due to more CO2 emission per product unit at the level of 2.88 tons CO2/ton surfactant, which is also more than the SDBS surfactant production process that released 2.46 tons CO2/ton surfactant.

Combination of natural silica and alumina sources for synthesis of MCM-22 zeolite.

Zeolite has become a promising material that can potentially play a pivotal role in resolving environmental crises. Among zeolite families, MCM-22 zeolite shows outstanding intrinsic properties associated with the topology and porous structure, offering ion-exchange advantages for catalytic activity processes. The synthesis of MCM-22 zeolite becomes challenging when concerning the cost and catalytic performance. To overcome this bottleneck, we demonstrate a sustainable route of a hydrothermal process using natural resources as starting materials. Rice husk from agricultural waste was used as a silica source while natural clays (kaolin and bentonite) were applied as alumina sources. The products from natural sources were compared with the use of commercial starting materials, e.g., NaAlO2 (for alumina) and Na2SiO3 and TEOS (for silica), in points of crystal, compositional, and morphological views. We showed that the high purity of MCM-22 zeolite can be obtained from rice husk silica (RHS) and aluminosilicate gel (ASG) extracted from kaolin, while the use of ASG extracted from bentonite tended to be unsuitable to generate the zeolite formation. We also studied the effects of reaction time and the ratio of RHS/ASG on the crystallinity and surface area of MCM-22. The architecture and acidity of an optimal product were explored by Nuclear magnetic resonance spectroscopy and Temperature-programmed desorption of ammonia, demonstrating the success of achieving well acidity.

Highly effective removal of perfluorooctanoic acid (PFOA) in water with DBD-plasma-enhanced rice husks.

Adsorption is regarded as an efficient method to eliminate per- and polyfluoroalkyl substances from an aqueous solution. In the present investigation, an adsorbent based on rice husks (RHs) was successfully prepared by phosphoric acid (PA) activation and dielectric barrier discharge (DBD) plasma treatment, and it was used to adsorb perfluorooctanoic acid (PFOA) from water. The electrodes employed in the experiment were planar type. This research investigated RH surface properties and adsorption capacity before and after modification using DBD plasma. The results revealed that the He-O2 plasma modification introduced oxygen-containing functional groups and increased the PFOA removal efficiency. Increasing the oxygen content and total gas flow rate to 30 vol.% and 1.5 L/min, respectively, with 10 min of RH plasma treatment time at 100 W plasma discharge power enhanced the PFOA removal efficiency to 92.0%, while non-treated RH showed the removal efficiency of only 46.4%. The removal efficiency of the solution increased to 96.7% upon adjusting the pH to 4. The adsorption equilibrium isotherms fitted the Langmuir model, and the adsorption kinetic followed the pseudo-second-order model. The maximum adsorption capacity was 565 mg/g when the Langmuir isotherm model was applied.

Development of Ni-Mo carbide catalyst for production of syngas and CNTs by dry reforming of biogas.

Biogas has been widely regarded as a promising source of renewable energy. Recently, the direct conversion of biogas over heterogeneous catalysts for the simultaneous production of syngas and carbon nanotubes exhibits a high potential for full utilization of biogas with great benefits. Involving the combined dry reforming of methane and catalytic decomposition of methane, the efficiency of process is strongly depended on the catalyst activity/stability, mainly caused by carbon deposition. In this study, Ni-Mo catalyst is engineered to provide a life-long performance and perform high activity in the combined process. The surface modification of catalysts by a controlled carburization pretreatment is proposed for the first time to produce a carbide catalyst along with improving the catalyst stability as well as the reactivity for direct conversion of biogas. The performance of as-prepared carbide catalysts is investigated with comparison to the oxide and metallic ones. As a result, the Ni-Mo2C catalyst exhibited superior activity and stability over its counterparts, even though the condensed nanocarbon was largely grown and covered on the surface. In addition, up to 82% of CH4 conversion and 93% of CO2 conversion could remain almost constant at 800 °C throughout the entire test period of 3 h under a high flowrate inlet stream of pure biogas at 48,000 cm3 g-1 h-1. The XPS spectra of catalysts confirmed that the presence of Mo2C species on the catalyst surface could promote the stability and reactivity of the catalyst, resulting in higher productivity of carbon nanotubes over a longer time.

Techno-economic assessment of co-production of edible bioplastic and food supplements from Spirulina.

Large amount of plastic wastes harming the environment have raised concerns worldwide on finding alternatives to non-biodegradable plastics. Microalgae has been found as a potential source for bioplastic production, besides its more common application in the pharmaceutical and nutraceutical industry. In this study, the objective was to techno-economically evaluate the large-scale co-production of Spirulina powder as food supplements and edible bioplastic for food packaging. The scale of production was large enough to satisfy 1% of local (Thailand) plastic demand (i.e., approx. 1200 MT y-1), and 1% of the global Spirulina demand (approx. 1000 MT y-1) as food supplements. Results showed that the co-production of the Spirulina powder and bioplastic revealed an attractive venture with a payback time (PBT) as low as 2.6 y and ROI as high as 38.5%. This was because the revenues generated were as high as US$ 55.6 million y-1, despite high capital (US$ 55.7 million) and operating (US$ 34.9 million y-1) costs. Sensitivity analysis showed differences in the profitability based on variations of major parameters in the study, where the split ratio of biomass used for food supplement versus bioplastic production and the bioplastic's selling price were found to be the most sensitive.

Upgradation of methane in the biogas by hydrogenation of CO2 in a prototype reactor with double pass operation over optimized Ni-Ce/Al-MCM-41 catalyst.

The upgradation of methane in biogas by hydrogenation of CO2 has been currently recognized as a promising route for efficient full utilization of renewable biogas with potential benefits for storage of renewable hydrogen energy and abatement of greenhouse gas emission. As a main constituent of biogas, CO2 can act as a backbone for the formation of additional CH4 by hydrogenation, then producing higher amounts of biomethane. In this work, the upgradation process was investigated in a prototype reactor of double pass operation with vertical alignment using an optimized Ni-Ce/Al-MCM-41 catalyst. The experimental results show that the double pass operation that removes water vapor during the run can significantly increase CO2 conversion, resulting in higher CH4 production yield. As a result, the purity of biomethane increased by 15% higher than a single pass operation. In addition, search for optimum condition of the process was carried out within an investigated range of conditions including flowrate (77-1108 ml min-1), pressure (1 atm-20 bar), and temperature (200-500 °C). The durability test for 458 h was performed using the obtained optimum condition, and it shows that the optimized catalyst can perform excellent stability with negligible influence by the observed change in catalyst properties. The comprehensive characterization on physicochemical properties of fresh and spent catalysts was performed, and the results were discussed.

Development of high-performance nickel-based catalysts for production of hydrogen and carbon nanotubes from biogas.

Selecting a suitable catalyst for implementing the simultaneous production of hydrogen-rich syngas and multi-walled carbon nanotubes through the integration of dry reforming and methane decomposition reactions has recently gained great interests. In this study, a series of bimetallic (NiMo/MgO) and trimetallic (CoNiMo/MgO, FeNiMo/MgO, CoFeMo/MgO) catalysts was prepared and evaluated for a catalytic activity of CH4 and CO2 conversions of biogas in a fixed bed reactor at 800 °C and atmospheric pressure. Among the investigated catalysts, the bimetallic NiMo/MgO catalyst showed the outstanding catalytic performance with 86.4% CH4 conversion and 95.6% CO2 conversion as well as producing the highest syngas purity of 90.0% with H2/CO ratio = 1.1. Moreover, the characterization of the synthesized solid products proved that the well-aligned structured morphology, high purity, and excellent textural properties of CNTs were obtained by using NiMo/MgO catalyst. On the other hand, using trimetallic catalysts which have the composition of Co and Fe leads to the severe deactivation. This could be attributed the catalyst oxidation with CO2 in biogas, resulting in the transformation of metals into large metal oxides. The integrative process with NiMo/MgO catalyst is regarded as a promising pathway, which has a high potential for directly converting biogas into the high value-added products and providing a green approach for managing the enormous amounts of wastes.

Effect of louver baffles installation on hydrodynamics of bubbling fluidization in biomass gasifier.

Biomass gasification by a bubbling bed gasifier has been a promising process to produce fuels from biomass. However, the performance is limited by gas aggregation in the gasifier. In this study, CFD simulations were used to investigate hydrodynamics in bubbling bed gasifiers installed with multilayer louver baffles to understand the roles of baffles on different aspects including gas aggregation, biomass-bed mixing, gas-biomass contact, and pressure drop. The designed baffles could reduce the gas aggregation particularly when the biomass is fed at the middle of the baffle zone. The baffles could enhance the biomass-bed mixing and the gas-biomass contact throughout the bed except near the biomass inlet. The installation of baffles would not significantly affect the overall pressure drop but slightly affect at the mid-level of the bed. For the system in this study, the baffled gasifier with biomass feeding at the middle of the baffled zone and the gas inlet velocity of 0.7 m/s could provide the best performance in term of hydrodynamics.

Effect of Co-Doping on Cu/CaO Catalysts for Selective Furfural Hydrogenation into Furfuryl Alcohol.

Cu/CaO catalysts with fine-tuned Co-doping for excellent catalytic performance of furfural (FAL) hydrogenation to furfuryl alcohol (FOL) were synthesized by a facile wetness impregnation method. The optimal Co1.40Cu1/CaO catalyst, with a Co to Cu mole ratio of 1.40:1, exhibited a 100% FAL conversion with a FOL yield of 98.9% at 100 °C and 20 bar H2 pressure after 4 h. As gained from catalyst characterizations, Co addition could facilitate the reducibility of the CoCu system. Metallic Cu, Co-Cu alloys, and oxide species with CaO, acting as the major active components for the reaction, were formed after reduction at 500 °C. Additionally, this combination of Co and Cu elements could result in an improvement of catalyst textures when compared with the bare CaO. Smaller catalyst particles were formed after the addition of Co into Cu species. It was found that the addition of Co to Cu on the CaO support could fine-tune the appropriate acidic and basic sites to boost the FOL yield and selectivity with suppression of undesired products. These observations could confirm that the high efficiency and selectivity are mainly attributed to the synergistic effect between the catalytically active Co-Cu species and the CaO basic sites. Additionally, the FAL conversion and FOL yield insignificantly changed throughout the third consecutive run, confirming a high stability of the developed Co1.40Cu1/CaO catalyst.

A modified approach for high-quality RNA extraction of spore-forming Bacillus subtilis at varied physiological stages.

BACKGROUND: High quality RNA is required for the molecular study. Sample preparation of the spore-forming, Gram-positive bacteria like Bacillus sp., remains challenging although several methods have been proposed. Those techniques were simply developed using cell samples at certain growth stages despite some molecular studies like transcriptomic analyses require RNA samples from different physiological stages. METHODS AND RESULTS: We developed the rapid, simple yet effective cell-lysis technique with limit use of harsh reagents by modifying the kit-based protocols. Appropriate lysozyme loading (20 mg/mL), incubation time (30 min), and temperature (37 °C) enabled cell lysis and enhanced RNA extraction from both vegetative cells and endospores of Bacillus subtilis TL7-3. High RNA Integrity Numbers and ratios of A260/A280 and A260/A230 of all RNA products collected during the batch cultivation confirmed that invert mixing with absolute ethanol prevented RNA damage during protein denaturation. With the process modification of the major steps in cell lysis and RNA extraction compared with the kit-based protocols that are typically used in laboratory work, interestingly, our modified protocol, simple-yet-effective, yielded higher concentration, purity, and integrity of RNA products from all cell samples collected at different physiological stages. While the kit-based protocols either failed to provide high RNA concentration or RNA purity and integrity for all cell samples particularly during the late-log, stationary, or sporulation. CONCLUSIONS: Therefore, we can claim the significance of this modified protocol to be applicable for RNA extraction to those spore-forming Gram-positive bacteria not limited to B. subtilis growing at varied physiological stages.

Low-cost alternative biodiesel production apparatus based on household food blender for continuous biodiesel production for small communities.

Fatty acid methyl esters (FAMEs) are sustainable biofuel that can alleviate high oil costs and environmental impacts of petroleum-based fuel. A modified 1200 W high-efficiency food blender was employed for continuous transesterification of various refined vegetable oils and waste cooking oil (WCO) using sodium hydroxide as a homogeneous catalyst. The following factors have been investigated on their effects on FAME yield: baffles, reaction volume, total reactant flow rate, methanol-oil molar ratio, catalyst concentration and reaction temperature. Results indicated that the optimal conditions were: 2000 mL reaction volume, 50 mL/min total flow rate, 1% and 1.25% catalyst concentration for refined palm oil and WCO, respectively, 6:1 methanol-to-oil molar ratio and 62-63 °C, obtaining yield efficiency over 96.5% FAME yield of 21.14 × 10-4 g/J (for palm oil) and 19.39 × 10-4 g/J (for WCO). All the properties of produced FAMEs meet the EN 14214 and ASTM D6751 standards. The modified household food blender could be a practical and low-cost alternative biodiesel production apparatus for continuous biodiesel production for small communities in remote areas.

Low-temperature and atmospheric pressure plasma for palm biodiesel hydrogenation.

Partially hydrogenated fatty acid methyl ester (H-FAME) is conventionally produced through partial hydrogenation under high pressure and elevated temperature in the presence of a catalyst. Herein, a novel green, catalyst-free, non-thermal and atmospheric pressure dielectric barrier discharge (DBD) plasma was employed instead of a conventional method to hydrogenate palm FAME. H-FAME became more saturated with the conversion of C18:2 and C18:3 of 47.4 and 100%, respectively, at 100 W input power, 1 mm gas-filled gap size and 80% H2 in the mixed gas at room temperature for 5 h, causing a reduction of the iodine value from 50.2 to 43.5. Oxidation stability increased from 12.8 to 20 h while a cloud point changed from 13.5 to 16 °C. Interestingly, DBD plasma hydrogenation resulted in no trans-fatty acid formation which provided a positive effect on the cloud point. This green DBD plasma system showed a superior performance to a conventional catalytic reaction. It is an alternative method that is safe from explosion due to the mild operating condition, as well as being highly environmentally friendly by reducing waste and energy utilization from the regeneration process required for a catalytic process. This novel green plasma hydrogenation technique could also be applied to other liquid-based processes.

Natural Kaolin-Based Ni Catalysts for CO2 Methanation: On the Effect of Ce Enhancement and Microwave-Assisted Hydrothermal Synthesis.

Natural kaolin-based Ni catalysts have been developed for low-temperature CO2 methanation. The catalysts were prepared via a one-step co-impregnation of Ni and Ce onto a natural kaolin-derived metakaolin using a microwave-assisted hydrothermal method as an acid-/base-free synthesis method. The influences of microwave irradiation and Ce promotion on the catalytic enhancement including the CO2 conversion, CH4 selectivity, and CH4 yield were experimentally investigated by a catalytic test of as-prepared catalysts in a fixed-bed tubular reactor. The relationship between the catalyst properties and its methanation activities was revealed by various characterization techniques including X-ray fluorescence, X-ray diffraction, Brunauer-Emmett-Teller, scanning electron microscopy, selected area electron diffraction, transmission electron microscopy, elemental mapping, H2 temperature-programmed reduction, and X-ray absorption near-edge structure analyses. Among the two enhancement methods, microwave and Ce promotion, the microwave-assisted synthesis could produce a catalyst containing highly dispersed Ni particles with a smaller Ni crystallite size and higher catalyst reducibility, resulting in a higher CO2 conversion from 1.6 to 7.5% and a better CH4 selectivity from 76.3 to 79.9% at 300 °C. Meanwhile, the enhancement by Ce addition exhibited a great improvement on the catalyst activities. It was experimentally found that the CO2 conversion increased approximately 7-fold from 7.5 to 52.9%, while the CH4 selectivity significantly improved from 79.9 to 98.0% at 300 °C. Though the microwave-assisted synthesis could further improve the catalyst activities of Ce-promoted catalysts, the Ce addition exhibited a more prominent impact than the microwave enhancement. Cerium oxide (CeO2) improved the catalyst activities through mechanisms of higher CO2 adsorption capacity with its basic sites and the unique structure of CeO2 with a reversible valence change of Ce4+ and Ce3+ and high oxygen vacancies. However, it was found that the catalyst prepared by microwave-assisted synthesis and Ce promotion proved to be the optimum catalyst in this study. Therefore, the present work demonstrated the potential to synthesize a nickel-based catalyst with improved catalytic activities by adding a small amount of Ce as a catalytic promoter and employing microwave irradiation for improving the Ni dispersion.

Catalytic pyrolysis of petroleum-based and biodegradable plastic waste to obtain high-value chemicals.

The petroleum-based plastics, high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP), and the biodegradable plastic, polylactide (PLA) were processed by thermal and catalytic pyrolysis to investigate their suitability as feedstock for chemical recycling. The influence of pyrolysis temperature (400-600 °C) and catalyst (zeolite, spent FCC, and MgO catalyst) on the pyrolysis liquid composition and yield was studied. The studied petroleum-based plastics had similar decomposition temperature ranges but produced their highest pyrolysis yields at different temperatures. Pyrolysis liquids from thermal degradation of HDPE and LDPE consisted high yield of waxes but those of PP and PLA consisted of both waxes and liquid oil. Catalysts affected not only the pyrolysis yield, but also the proportions of liquid oil and wax in pyrolysis liquids. Alkenes, alkanes, and aromatics were the main compounds in the pyrolysis liquids. Spent FCC catalyst reduced the production of waxes and increased the production of gasoline-range hydrocarbons and aromatics. MgO catalyst led to high coke formation from polyolefins and PLA. Lactic acid, lactide and propanoic acid were examples of valuable chemicals recovered from the pyrolysis of PLA. Lactide was the main product (up to 79%) of catalytic pyrolysis with zeolite at 400 °C. Spent FCC catalyst produced mostly propanoic acid at 400 °C but at 600 °C, L-lactic acid became the most abundant compound.

Solvent-Free Hydrodeoxygenation of Triglycerides to Diesel-like Hydrocarbons over Pt-Decorated MoO2 Catalysts.

In the present work, the solvent-free hydrodeoxygenation of palm oil as a representative triglyceride model compound to diesel-like hydrocarbons was evaluated in a batch reactor using Pt-decorated MoO2 catalysts. The catalysts with various Pt loadings (0.5-3%) were synthesized by an incipient wetness impregnation method. The metallic Pt and MoO2 phases were detected in the XRD patterns of as-prepared catalysts after the reaction and acted as active components for the deoxygenation reactions. The XPS experiments confirmed the existence of metallic Pt and PtO x species. The XANES investigation of Mo L3-edge spectra elucidated a change in the valence state by the transformation of MoO3 into MoO2 species after the deoxygenation reaction. The TEM observation revealed the formation of Pt nanoparticles in the range of 1-3 nm decorated on MoO2 species. The number of acid sites increased with stronger metal-support interactions on increasing the Pt loading. The catalytic performance of the MoO2 catalyst significantly improved with a small amount of Pt decoration. However, the further increase in Pt loading did not relatively increase the deoxygenation activity due to the formation of the agglomerated Pt particles. The high performance of the decorated catalysts could be attributed to the moderate acidity from the Pt dispersed on MoO2 toward decarbonylation and decarboxylation reactions.

Simultaneous Enhancement of Photocatalytic Bactericidal Activity and Strength Properties of Acrylonitrile-Butadiene-Styrene Plastic Via a Facile Preparation with Silane/TiO2.

This work aims to enhance the photocatalytic antibacterial performance of plastics according to the JIS Z 2801:2010 standard, and to determine their mechanical properties by studying: (i) the influence of calcination on titanium dioxide (TiO2); (ii) modification with different TiO2 concentrations, and; (iii) the effect of silane as a coupling agent. Acrylonitrile-butadiene-styrene plastics (ABS) and Escherichia coli (E. coli) were chosen as the model plastic and bacteria, respectively. The 500 °C calcined TiO2 successfully provided the best photoantibacterial activity, with an approximately 62% decrease of E. coli colony counts following 30 min of exposure. Heat treatment improved the crystallinity of anatase TiO2, resulting in low electron-hole recombination, while effectively adsorbing reactants on the surface. ABS with 500 °C-calcined TiO2 at the concentration of 1 wt % gave rise to the highest performance due to the improved distribution of TiO2. At this point, blending silane coupling agent could further improve the efficacy of photoantibacterial activity up to 75% due to greater interactions with the polymer matrix. Moreover, it could promote a 1.6-fold increase of yield strength via increased adherent bonding between TiO2 and the ABS matrix. Excellent photocatalytic and material stability can be achieved, with constant photocatalytic efficiency remaining for up to five reuse cycles without loss in the yield strength.

Intrinsic kinetic study of 1-butene isomerization over magnesium oxide catalyst via a Berty stationary catalyst basket reactor.

In this work, we studied the intrinsic kinetics of 1-butene isomerization over a commercial MgO catalyst using a Berty-type reactor (gradient-less recycle reactor). The Berty-type reactor has a behavior equivalent to a continuous stirred tank reactor (CSTR) with perfect mixing. The experimental results from this reactor were selected in a range in the absence of external and internal mass- and heat-transfer resistances, thereby representing the intrinsic kinetics. The 1-butene isomerization was carried out under atmospheric pressure, a WHSV of 1.05-5.47 h-1, and the reaction temperature from 350 °C to 450 °C. The kinetic models were established on the basis of different mechanisms for 1-butene isomerization over MgO. The results showed that the LHHW kinetic model provided the best agreement with the experimental data. The reactions involve three steps, including (1) adsorption of 1-butene on the active site, (2) the chemical surface reactions of 1-butene to trans- and cis-2-butene, and (3) the desorption of trans- and cis-2-butene. The surface reactions were assumed to be the rate-determining step. The percentage error of all predicted values was less than 5% under the studied operating conditions.

Techno-economic analysis of vanillin production from Kraft lignin: Feasibility study of lignin valorization.

Kraft lignin waste is valorized by converting it into vanillin via the oxidation process. To obtain the highest yield of vanillin, feed concentration of lignin, reaction temperature, and oxygen partial pressure are optimized. Three separation cases, i.e. solvent extraction followed by distillation (Case I), solvent extraction (Case II), and vacuum distillation (Case III) are simulated and compared to identify the most suitable separation process. The results reveal that the highest vanillin yield of 9.25% is attainable using feed concentration of Kraft lignin of 30 g/l, operating temperature of 110 °C, and oxygen partial pressure of 5 bars. Case I appears to be the most suitable method of separation since it consumes the lowest amount of energy and gives the best economic returns, with a payback period of 6.19 years and internal rate of return (IRR) of 22.63%.