Special Issue “Recent Advances in Processing Technologies for Substance Extraction, Separation, and Enrichment”

Substance separation has always been the foundation of production processes in a variety of industrial sectors such as hydrometallurgy, natural compounds extraction, food industry, pharmaceutical industry, and environmental engineering. Separation processes can be performed for different purposes, e.g., extraction of valuable components from less valuable matrices, removal of impurities, and enrichment of trace components. Conventional techniques, including distillation, liquid-phase extraction (LPE), solid-phase extraction (SPE), precipitation, and electrodeposition, are the dominant technologies in the separation of various types of substances and have found a broad application in both lab-scale research and industrial production. With the development of new theories, materials, and technologies, significant advancements have occurred in recent decades that have demonstrated advantages with regards to efficiency, energy saving, environment friendliness, costs, and value addition. In particular, new modeling techniques for process optimization, novel extraction and separation systems, green solvents, and novel solid-phase materials (e.g., mesoporous and nanostructured materials) for extraction have been developed and adopted by engineers for various applications. Typical examples include the modeling and simulation of electrochemical processes (deposition and separation), liquid–liquid extraction process for the optimization of mass transfer performance, minimization of energy consumption, application of green solvents and new ionic liquids, tailored materials for highly selective separation, membranes for SPE, extraction of natural products for nutritional, and medical and health care applications. The use of these new materials and technologies can effectively improve the mass transfer performance and separation efficiency, facilitate environmental and/or user friendliness, and improve people’s quality of life.

This Special Issue on the “Recent Advances in Processing Technologies for Substance Extraction, Separation and Enrichment” aimed to provide a forum for scientists to present their research findings in new solvents, extractants, solid-phase materials, techniques, as well as modeling and optimization methodologies, to address some of the most challenging problems faced by industries today and to demonstrate the potential value of a variety of resources which may previously have been overlooked. Thanks to the tremendous efforts of our esteemed authors, this Special Issue is brimming with excitement, featuring twenty-one cutting-edge research papers and five comprehensive review articles. Dive into the forefront of innovation where we explore diverse extraction systems—from the depths of hydrometallurgy to the extraction of nutritious natural compounds. Discover how novel green solvents and advanced technologies are revolutionizing the utilization of secondary resources. This collection promises to ignite your curiosity and inspire breakthroughs in extraction science.

Separation technologies play a crucial role in hydrometallurgy. Several research papers and review articles have presented the use of different extraction techniques for the separation of different elements [1,2,3,4,5,6,7]. Their applications cover the separation of base metals, recovery of precious metals, and separation of rare earth metals. Waste water treatment in this industry via separation technology has also been presented in a research paper [8].

The utilization of natural organic substances (such as bioactive compounds, proteins, and nutritional components in natural resources) and food industry residues (such as nutrients, health care products, and skin care components) has been a fascinating research topic in recent decades. This Special Issue involves a number of research and review articles that present the use of different technologies for the extraction of such components from different resources [9,10,11,12,13,14,15,16,17,18,19,20,21,22]. In many of these contributions, various novel reagents and methods have been utilized by the authors to demonstrate the value of new technologies, including three-phase partitioning [10], reactive extraction [12], supercritical fluid extraction [14,15], deep eutectic solvents [17,20], enzymatic processing [11,23], ultrasound assisted extraction [11,13,15,19,22], microwave-assisted extraction [13], centrifugal extractor [20], pulsed electric field technology [19,21], and high-pressure homogenization [13,22]. Many of the papers dealing with natural compounds are accompanied by an assessment of their properties, such as antioxidant activity, providing an indication of the extraction’s value [13,15,17,19,24].

Different forms of membrane separation technologies that feature a reduced footprint, low-energy requirements, and that are environmentally benign are attractive areas for research and applications, as indicated by the papers in this Special Issue [25,26].

As the guest editors, we would like to express our gratitude to all the authors who generously contributed their excellent work to this Special Issue. We also acknowledge the colleagues and assistant editors involved in this Issue, especially Lily Liu and Scott Pan, for their collaboration and cooperation in the whole editing process.