Deep eutectic solvents, as an alternative to ionic liquids, have greener credentials than ionic liquids, and have attracted considerable attention in related chemical research. Deep eutectic solvents have attracted increasing attention in chemistry for the extraction and separation of various target compounds from natural products. This review highlights the preparation of deep eutectic solvents, unique properties of deep eutectic solvents, and synthesis of deep-eutectic-solvent-based materials. On the other hand, application in the extraction and separation of deep eutectic solvents is also included in this report. In this paper, the available data and references in this field are reviewed to summarize the applications and developments of deep eutectic solvents. Based on the development of deep eutectic solvents, an exploitation of new deep eutectic solvents and deep eutectic solvents-based materials is expected to diversify into extraction and separation.

Development of deep eutectic solvents applied in extraction and separation.

Economically viable microalgal biodiesel production is unrealistic and unsustainable owing to expensive harvesting or dewatering techniques. Hence, immense and meticulous exploration of harvesting process is essential to identify knowledge leads by which suitable harvesting technique could be ascertained for lucrative biodiesel production. With this in view, this review aims to collate and highlight the spectrum of harvesting techniques applied to microalgae, i.e., conventional – modern, high cost- inexpensiveness, energy efficient- energy consuming process. At the outset, global energy outlook and demand had been critically addressed, and the scientific ways to tackle or satiate the fuel demand had also been highlighted in this reveiw. This review manuscript has thrown widespread light on the physical harvesting methods namely centrifugation, sedimentation, filtration, flotation and technical advantages thereof. Due to the energy-intensive and cost barrier of physical harvesting techniques, chemical methods entailing organic, inorganic, and electroflocculation have come to limelight and in this regard, microalgae used, floc recovery and the dose of flocculants have been compared and presented in detail. Further, state of the art harvesting techniques viz., bioflocculation by microalgae/bacteria, flocculation by pH adjustment, and magnetic nanocomposite based microalgal harvesting had been critically articulated. Besides discussing the several methods, this paper has summarized the key challenges in conventional and advanced harvesting techniques and also provided the scope thereof. Hence, the key suggestions and findings given in this manuscript would positively offer a well-defined roadmap in choosing foreseeable harvesting technology for cost-effective microalgal biofuel development.

A comprehensive review on harvesting of microalgae for biodiesel – Key challenges and future directions

Formation of type III Deep Eutectic Solvents and effect of water on their intermolecular interactions

Microalgae can be used as a source of alternative food, animal feed, biofuel, fertilizer, cosmetics, nutraceuticals and for pharmaceutical purposes. The extraction of organic constituents from microalgae cultivated in the different nutrient compositions is influenced by microalgal growth rates, biomass yield and nutritional content in terms of lipid and fatty acid production. In this context, nutrient composition plays an important role in microalgae cultivation, and depletion and excessive sources of this nutrient might affect the quality of biomass. Investigation on the role of nitrogen and phosphorus, which are crucial for the growth of algae, has been addressed. However, there are challenges for enhancing nutrient utilization efficiently for large scale microalgae cultivation. Hence, this study aims to highlight the level of nitrogen and phosphorus required for microalgae cultivation and focuses on the benefits of nitrogen and phosphorus for increasing biomass productivity of microalgae for improved lipid and fatty acid quantities. Furthermore, the suitable extraction methods that can be used to utilize lipid and fatty acids from microalgae for biofuel have also been reviewed.

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Influence of Nitrogen and Phosphorus on Microalgal Growth, Biomass, Lipid, and Fatty Acid Production: An Overview.

The energy demands and costs of harvesting microalgal biomass make it unrealistic and unsustainable for economically feasible microalgal biofuel production Therefore, meticulous exploration of the harvesting processes is essential to identify appropriate harvesting techniques for potentially commercialized microalgal biodiesel production Flocculation may be a superior method when considering harvesting efficiency, economic cost, energy consumption and technical feasibility This review sheds some light on the recent progresses of physical/chemical flocculation and bioflocculation applied in the microalgal biomass harvesting processes Physical flocculation techniques are energy-intensive and require special equipment, creating the cost barrier for microalgal biomass harvesting Magnetic particle flocculation is much more efficient and is also recyclable In contrast, chemical flocculation that involves the application of organic and inorganic flocculants, is now in the limelight The microalgae species applied, the dosages of flocculants as well as flocculation recovery efficiencies are compared and presented in detail in this review In addition, bioflocculation as a harvesting techniques is critically described, in particular the mechanisms of autoflocculation, a promising bioflocculation by co-cultivation of microalgae with microorganisms, are explored This review also disclosed the effects of flocculant application on downstream processes, especially when chemical flocculants are applied This review intends to provide guidance for the long-term adoption of these economically beneficial mature flocculation recovery technologies in the biofuel industry Despite of considerable progress, key challenges such as further reduction of costs and the minimization of downstream product pollution risks in conventional and advanced harvesting techniques, must be addressed This article also suggests the directions for future research in microalgae harvesting and argues that the production of microalgae biofuels under potential policy intervention should be carried out in a healthy and sustainable way

A review on flocculation as an efficient method to harvest energy microalgae: Mechanisms, performances, influencing factors and perspectives

Separation of the ethanol/water azeotropic mixture using ionic liquids and deep eutectic solvents

Separation of the isopropanol-water azeotropic mixture using ionic liquids

Ionic liquids as entrainers for the separation of azeotropic mixtures: Experimental measurements and COSMO-RS predictions

Viscosities of pure protic ionic liquids and their binary and ternary mixtures with water and ethanol

The harvesting of Nannochloropsis oceanica was studied using magnetic separation with naked iron oxide particles. Emphasis was given to the effect of pH on harvesting efficiency, while mixing time ...

Elenitsa Boli

Papers

Separation of the ethanol/water azeotropic mixture using ionic liquids and deep eutectic solvents

Separation of the isopropanol-water azeotropic mixture using ionic liquids

Ionic liquids as entrainers for the separation of azeotropic mixtures: Experimental measurements and COSMO-RS predictions

Viscosities of pure protic ionic liquids and their binary and ternary mixtures with water and ethanol

Magnetic harvesting of marine algae Nannochloropsis oceanica