Screening of suitable ionic liquids as green solvents for extraction of eicosapentaenoic acid (EPA) from microalgae biomass using COSMO-RS model

Omega-3 poly unsaturated fatty acids (PUFA) particularly eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), have many health benefits including reducing the risk of cancer and cardiovascular disease. Recently, the use of ionic liquids (ILs) in lipid extraction from microalgae provides the potential to overcome common drawbacks, offers several other benefits. To date, very limited researches are available to focus on extracting microalgae lipid and PUFA in particular by using ILs. The objective of current work is to screen the potential ILs that can be applied in EPA extraction. In this study, fast ILs screening was performed with the help of a conductor like screening model for real solvents (COSMO-RS) and the ILs with higher capacity values for use in extraction of EPA were compared. According to the results, the highest capacity for EPA extraction among 352 screened cation/anion combinations belongs to [TMAm][SO4]. It is expected to achieve a higher yield of EPA once applying this combination as the solvent in the process of extraction. ILs with small anions were observed to have higher capacities, as well possessing higher charge density compared to larger ones, and therefore, they are more preferable for extraction purposes. Moreover, shorter alkyl chain cations are preferred when using imidazolium-based IL, which agrees with experimental data

Ionic liquid method for the extraction of lipid from microalgae biomass: a review

Microalgae are an alternative source of renewable energy and high-value products for pharmaceutical, nutraceutical, etc., due to rich in carbohydrates, proteins, lipids, and high-density lipoproteins. Existing methods for cell disruption and extraction are costly and suffered from low proficiencies. Ionic liquids are proven to be an environmentally friendly substitute to conventional volatile organic solvents. They have been used in extracting different types of biomass, including microalgae. This article reviews the potential of ILs in extracting biomolecules, lipid, and omega-3, from microalgae biomass. The physicochemical properties of ILs, including viscosity, density, and melting point, their advantages and limitation, as well as toxicity and recyclability of ILs in lipid processing, are discussed

Sustainable bio-economy that delivers the environment-food-energy-water nexus objectives: the current status in Malaysia

Biomass is a promising resource in Malaysia for energy, fuels, and high value-added products. However, regards to biomass value chains, the numerous restrictions and challenges related to the economic and environmental features must be considered. The major concerns regarding the enlargement of biomass plantation is that it requires large amounts of land and environmental resources such as water and soil that arises the danger of creating severe damages to the ecosystem (e.g. deforestation, water pollution, soil depletion etc.). Regarded concerns can be diminished when all aspects associated with palm biomass conversion and utilization linked with environment, food, energy and water (EFEW) nexus to meet the standard requirement and to consider the potential impact on the nexus as a whole. Therefore, it is crucial to understand the detail interactions between all the components in the nexus once intended to look for the best solution to exploit the great potential of biomass. This paper offers an overview regarding the present potential biomass availability for energy production, technology readiness, feasibility study on the techno-economic analyses of the biomass utilization and the impact of this nexus on value chains. The agro-biomass resources potential and land suitability for different crops has been overviewed using satellite imageries and the outcomes of the nexus interactions should be incorporated in developmental policies on biomass. The paper finally discussed an insight of digitization of the agriculture industry as future strategy to modernize agriculture in Malaysia. Hence, this paper provides holistic overview of biomass competitiveness for sustainable bio-economy in Malaysia

Experimental and numerical evaluation of napier grass gasification in an auto-thermal fluidized bed reactor

Biomass gasification is a promising renewable energy generation technology as alternative to fossil based fuels for cleaner and sustainable future. At site auto-thermal gasifier built in affordable economic scale can overcome the high costs of grid lining, supplementary resources and the delivery of feedstock as main target for this study. A biomass gasification system with Napier grass as feedstock was investigated with the target of the producer gas to be used in direct combustion for power generation. The study consists of two main parts of experimental evaluations and numerical models. Experiments carried out to study the effect of three different operating parameters namely, temperature, equivalence ratio (ER) and static bed height (SBH) on the gasification of Napier grass in an auto-thermal bubbling fluidized bed gasifier. The results showed that the temperature has the most significant effect on the production of syngas as well as the composition of combustible species. The highest yield of syngas, with highest compositions of hydrogen and carbon monoxide and lowest yield of residues (i.e. biochar, tar and ash) were achieved at maximum temperature of 824°C. ER on the other hand has more complex effects on responses. The increase in ER up to 0.33 favored the yields of syngas, H2 and CO however the inverse effect was observed for ER above 0.33. SBH was found an important factor to effect on the production of H2 and CO and the maximum yields of each obtained at temperature of 824°C, ER of 0.33 and SBH of 0.105m. Common challenges encountered in performing the experiments were related to the complexity and instability of the process and the difficulties to maintain the temperature at a constant level due to the auto-thermal characteristics. Difficulties are expected to be diminished once achieved a steady-state operating condition through process improvement and optimization to which the process become adaptable to any imposed variations such as different feedstock types.An integrated numerical simulation were developed to study over hydrodynamics and thermodynamics of the gasification process. Hydrodynamics of solid particles fluidization were modelled to study on the effect of superficial velocity, viscous and drag models on the expansion of fluidizing bed, formation and distribution of bubbles inside the gasifier. The effect of air distributor plate with different pore diameters was modelled individually to determine the initial condition of the fluid as entered the gasifier. The results showed that the turbulent model of RNG K-Ɛ describes the actual process more accurately than other fluid regimes. Laminar and turbulent models although resulted in similar bed expansion level, the turbulent model showed higher distribution of solid particles and their related interactions as the result. Thermodynamic studies were conducted to simulate the heat distribution and to determine the temperature profile of the reactor at any time step of the operation. The temperature values at steady operation were verified by experimental records. The conduction heat transfer from gasifier media into the center of a single particles with different diameters were studied individually to calculate the particle degradation period. It was found from the results that fully degradation of a particle to solid biochar as entered the gasifier at constant temperature takes place after 0.66, 1.1 and 1.55 seconds for particles with 300,500 and 700 μm diameters respectively. The effect of particle size and initial reactor temperature on heat distribution were evaluated as well. Using the model eases the monitoring of system behavior while functions under various operating conditions. The findings from empirical optimization while integrated with numerical models provides an in-depth understanding over the gasification process and facilitates the scale-up determinations so that the technology in the future can be utilized in larger scales to provide power from biomass particularly in form of electricity in rural area

Experimental Evaluation of Napier Grass Gasification in an Autothermal Bubbling Fluidized Bed Reactor

Air gasification of Napier grass (NG) was studied with the target of producing combustible synthesis gas to be used in direct combustion for power generation. A small-scale autothermal bubbling fluidized bed gasifier was used to investigate the effect of reactor temperature, equivalence ratio (ER), and static bed height (SBH) on gasification performance and combustibility of the producer gas. The main generated species in syngas were identified through gas chromatography (GC) analysis. Minimum fluidization conditions were determined at different levels of SBH. Experiments carried out with two intentions of first, to achieve the highest composition of combustible species to ensure the maximum Lower Heating Value (LHV) of syngas and second, to obtain a high performance process with maximum yield of syngas and minimum residues. The results showed that the temperature and ER have significant effects on syngas yield and composition. SBH was found have a substantial effect on the production of H2 and CO. The results from this study was compared to other gasification studies from literature which have evaluated biomass gasification in bubbling fluidized bed reactors with different scales but almost similar method of experimentation. The purpose of verification was to demonstrate the effect of different reactor scales and heating characteristics on the results

Ionic liquid-based microwave-assisted extraction of protein from Nannochloropsis sp. biomass

Considerable evidence supports the enhanced utilization of high-quality protein to obtain optimal health subsequences. Microalgae are a valorous source of proteins that can be employed as functional, nutritional, and remedial supplies. An effective microwave-assisted extraction method based on ionic liquids has been utilized in this study to extract proteins from microalgae Nannochloropsis oceanica biomass. The study of microwave-assisted extraction was carried out under varying conditions of temperature (30–80  °C), extraction time (5–35  min), and IL concentration (0–4.67% w/v). Among the six types of examined IL, choline acetate was an effective one for extracting total protein from microalgae biomass. The highest protein yield was obtained at 0.5  g microalgae, 2% w/v [Ch][Ac], and 40  °C for 30  min, representing 26.35% of protein yield and 65.06% of total protein extracted from the Nannochloropsis oceanica biomass. Meanwhile, conventional method of Soxhlet resulted in the protein yield of 0.63%. Only 1.56% of total Nannochloropsis oceanica protein was extracted by extraction method of Soxhlet which uses the hazardous solvent. The outcomes illustrated the superiority of [Ch][Ac]-based microwaveassisted extraction to conventional methods. This innovative procedure is recommended to have significant usage for the separation of proteins. The outcomes from this study would be beneficial in recognizing and harnessing significant microalgae biochemical from IL-based microwave-assisted extraction process to develop new and improved bioproduct technologies

High current density charging of zinc-air flow batteries: Investigating the impact of flow rate and current density on zinc electrodeposition

International audienc

Experimental Evaluation of Napier Grass Gasification in an Autothermal Bubbling Fluidized Bed Reactor

Air gasification of Napier grass (NG) was studied with the target of producing combustible synthesis gas to be used in direct combustion for power generation. A small-scale autothermal bubbling fluidized bed gasifier was used to investigate the effect of reactor temperature, equivalence ratio (ER), and static bed height (SBH) on gasification performance and combustibility of the producer gas. The main generated species in syngas were identified through gas chromatography (GC) analysis. Minimum fluidization conditions were determined at different levels of SBH. Experiments carried out with two intentions of first, to achieve the highest composition of combustible species to ensure the maximum Lower Heating Value (LHV) of syngas and second, to obtain a high performance process with maximum yield of syngas and minimum residues. The results showed that the temperature and ER have significant effects on syngas yield and composition. SBH was found have a substantial effect on the production of H2 and CO. The results from this study was compared to other gasification studies from literature which have evaluated biomass gasification in bubbling fluidized bed reactors with different scales but almost similar method of experimentation. The purpose of verification was to demonstrate the effect of different reactor scales and heating characteristics on the results

Enhancing electrochemical performance and stabilizing zinc anode in mild acidic electrolyte using combined additive

Rechargeable zinc-based batteries having aqueous electrolytes are renowned as promising alternatives for large scale energy storage systems (ESSs). However, in mild acidic electrolytes, zinc anodes pose several issues that have yet to be overcome. For tackling the major difficulties of zinc anodes, electrolyte engineering is the most practical and cost-effective strategy. Notwithstanding the broad variety of mechanisms associated with different electrolyte additives, the function of a single additive is straightforward. Finding combined additives with broader functionalities and greater efficacy is crucial. In this work, the combination of ionic liquid (IL) 1-butyl-1-methylpyrrolidinium dicyanamide ([BMPY][DCN]) and ethylene glycol (EG) as additives in an aqueous electrolyte 3 M ZnSO4 proves to be an effective strategy for simultaneously enhancing both zinc dissolution and deposition. IL significantly enhances zinc (Zn) dissolution and deposition while EG plays an important role in suppressing hydrogen evolution reaction (HER)and corrosion. Thus, 13.50 % improvement in capacity is achieved by the mixed additive EG + IL/ZnSO4 compared with the 3 M ZnSO4 electrolyte. In the Zn//Zn symmetrical system at 2 mA cm−2, the mixed additive greatly augments the cyclability of zinc, reaching over 400 h while maintaining excellent coulombic efficiency (CE). In-situ XAS and FT-EXAFS analyses confirm the high activities of both zinc oxidation/reduction in the mixed additive electrolyte. Results demonstrate that EG + IL/ZnSO4 can be applied to increase the cyclability of aqueous zinc-based batteries while sustaining high performance