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Smart Factory of Microalgae in Environmental Biotechnology
Published in Pau Loke Show, Wai Siong Chai, Tau Chuan Ling, Microalgae for Environmental Biotechnology, 2023
Shazia Ali, Kuan Shiong Khoo, Hooi Ren Lim, Hui Suan Ng, Pau Loke Show
To form a large biomass collection, flocculation is the process that should be considered, and this procedure goes by circulating algal cells for settling. Auto-flocculation occurs when carbonates precipitate at a high pH with algal cells due to carbon dioxide intake by the algae (Vandamme, Foubert, and Muylaert 2013). Chemical flocculant that contaminates biomass is a significant problem in microalgal harvesting by flocculation as it can affect the end product (Branyikova et al. 2018). Gravity sedimentation is a straightforward method for separating algae from water and wastewater. Flotation is a sort of gravity sedimentation that is more effective and advantageous than sedimentation as it can capture pieces with thickness of less than 500 μm (de Souza Leite and Daniel 2020). Membrane filtration eliminates the need for chemicals, eliminates phase transitions, and ensures 100% solid retention (Mat Aron et al. 2021). Modifying the configuration of the filtration system itself by integrating auxiliaries such as air scouring and vibration into the filtration systems is one of the most popular ways now employed in anti-fouling harvesting (Farahah Mohd Khairuddin, Idris, and Irfan 2019). Centrifugation harvesting is characterized by high-capture efficiency under significant consumption of energy and limited flow rates, which accounts for around 90%. Centrifugation is a separating process for particles from a solution where then the particles are captured in the centrifuge tube (Dassey and Theegala 2013).
Prospect of Melt Crystallization
Published in Gerard F. Arkenbout, Melt Crystallization Technology, 2021
When a crystalline phase is formed from a fluid phase, the process is commonly called crystallization and the vessel used for generating the solid phase a crystallizer. Crystallization is one of the oldest unit operations and a major separation and purification technique in the chemical industry. Large quantities of crystalline substances are manufactured commercially. Some examples are sodium chloride and sucrose, with production rates of over 100 million metric tons per year. The organic chemical industry needs efficient separation methods, too. After all, following every chemical reaction, the resulting mixture must be physically separated into the various products (which then must be purified). The separation methods commonly used today in the organic chemical industry are distillation and extraction. Crystallization (from solution or from the melt) comes in third. Although crystallization from the melt is more difficult to realize on a technical scale, it potentially offers the organic chemical industry several important separation and purification advantages.
Environmental Nanoresearch Centers
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Tonya R. Pruitt, Matthew Y. Chan, Aaron J. Prussin, Jeffrey M. Farner, Arielle C. Mensch, Michael F. Hochella
Environmental samples are often heterogeneous mixtures that contain many different components. Frequently, the nanoparticle of interest is a tiny fraction of the collected sample. Therefore, to increase the chances of finding the particle of interest, the first step of analysis is often mechanical or chemical separation. The separation method is dependent on the makeup of the sample and the feature of interest. Filtration, sedimentation, and centrifugation are common mechanical separation techniques, whereas chromatography, distillation, and extraction are common forms of chemical separation. Though each of these techniques requires common laboratory equipment, their frequent use in environmental nanoresearch laboratories often results in designated bench space contrary to traditional nanore-search centers. Additionally, high-velocity ultracentrifuges prove to be especially useful in separating out nanoparticles from environmental samples and are becoming essential components of environmental nanoresearch centers. Further, ultracentrifuges are critical for purifying biological nanoparticles, such as viruses (Hermens et al., 1999; Reimer et al., 1967).
Laboratory suspension freeze concentration (Lab SFC) followed by a simple centrifugal procedure for separation
Published in Drying Technology, 2022
Lei Xu, Zhengkai Liao, Aditya Putranto, Xiao Dong Chen
In laboratory practice, if low temperature concentration method is preferred, freeze concentration is a good option. The separation efficiency may not need to be so high for economic purposes like that in a large industrial operation. In view of SFC’s difficult separation method and usually expensive equipment investment, a lab device with simpler design is desirable. Here a centrifugal separation method to replace wash-column method was investigated together with a single stage SFC. Centrifugation is a common solid-liquid separation method that uses centrifugal force creating a greater driving force. Centrifugal separation mode has been successfully applied to block freeze concentration.[21] The ice phase obtained by block freeze concentration is of a porous solid matrix.
Polycyclic aromatic hydrocarbons in aquatic animals: a systematic review on analytical advances and challenges
Published in Journal of Environmental Science and Health, Part A, 2022
Ivelise Dimbarre Lao Guimarães, Francielli Casanova Monteiro, Júlia Vianna da Anunciação de Pinho, Paloma de Almeida Rodrigues, Rafaela Gomes Ferrari, Carlos Adam Conte-Junior
Chromatographic methods are used to separate target analytes from co-extracted interferences in samples and can be divided into two main categories: GC and HPLC. GC is the technique of choice for organic compounds, which can be volatilized without being decomposed or chemically rearranged. HPLC is a useful separation technique for semi-volatile and nonvolatile chemicals or for analytes that decompose on heating. Successful liquid chromatography separation requires the analyte(s) of interest to be soluble in the solvent(s) selected as the mobile phase. Chromatographic methods achieve separation by passing a mobile phase through a stationary phase. The mixture constituents are separated by the difference in elution over the stationary phase with different retention times. The compounds that interact strongly with the stationary phase elute slowly (longer retention times), while compounds that remain in the mobile phase elute rapidly (shorter retention times).[13,23,24]
Evaluation of Pressure Filtration of Coal Refuse Slurry: Effects of pH, Filtration, and Air-Blow Times
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Slurry impoundments storing fine coal refuse can lead to environmental problems such as acidic water, siltation of streams, land property devaluation, and in extreme cases, dam failures (Schubert 1979). Advanced coal preparation techniques call for safer, environmental friendly, and efficient means of coal processing (Kawatra 2020; Kawatra and Eisele 2001). Pressure filtration provides a possible approach to reduce or even eliminate the need for slurry impoundments thereby providing an alternate means of handling coal refuse with potentially less environmental footprint. Filtration is the process of separating the solids in a slurry from the bulk liquid by retaining the solids (filter cake) on a porous filter medium (cloth) while allowing the liquid (filtrate) to pass through the medium. Pressure filtration operates at pressures that are greater than atmospheric. The differential pressure applied on the slurry can be several tens of atmospheres, leading to increased water recovery and drier filter cakes usually without the need for additional chemical flocculants. This process has the potential to improve water conservation, minimize environmental impact, reduce area requirements for disposal, and provide a safer operation (Alam et al., 2011). One study highlighted potential economic benefits of using pressure filtration as an alternative to the expense of capping and reclaiming the slurry impoundment area (Pepper 2012).