Electrostatic Separation as an Entry into Environmentally Eco-Friendly Dry Biorefining of Plant Materials

Abstract

Today, most technologies used to fractionate plant materials are based on expensive chemical processes that often have negative environmental impacts by consuming water, energy, and solvents and creating large quantities of effluents. In addition, during the separation step, the major components are often partially degraded. Achieving high fractionation yields while maintaining the integrity of the macromolecular structure is a major challenge for the next generation of biomass refining processes. Electrostatic separation (ES), which enables the production of enriched fractions in compounds of interest while preserving their (native) functionalities has emerged as an ecofriendly biotechnology for the fractionation of agro-resources in dry conditions. In this review, the potential of ES in a biorefinery scheme is evaluated and the technological obstacles that still need to be overcome for its full deployment at industrial scale are identified.

Rapeseed (Brassica napus): Processing, Utilization, and Genetic Improvement

“…To avoid the usage of chemicals for the extraction and concentration of proteins, and to eliminate lignocellulosic fiber, multiple techniques were proposed [31][32][33]. For instance, dry fractionation, which consisted of a combination of mechanical separation (milling) with electrostatic (particle charge) or turbo (density) separation was reported to enrich protein and phenolic fractions from plant materials due to the lignin removal [34][35][36].…”

Combination of Dry Milling and Separation Processes with Anaerobic Digestion of Olive Mill Solid Waste: Methane Production and Energy Efficiency

“…Conversely, the negatively charged fraction ESn− (brown) contains a greater amount of homogeneous and fibrous small particles. Basset et al and Barakat and Mayer attributed the differences in color and morphology to the differences in biochemical composition, which in turn depend upon the origin of the plant tissues [16,23].…”

“…Nevertheless, its lignin content (31%) was lower than those of the ESp+ (41%) and UFM0.1 (31%). Barakat et al investigated the coupling of ES and enzymatic hydrolysis of wheat straw [23]. After ES, the wheat straw fractions were hydrolyzed with an enzymatic cocktail.…”

Preserving the Cellular Tissue Structure of Maize Pith Though Dry Fractionation Processes: A Key Point to Use as Insulating Agro-Materials

“…Electrostatic separation: Electrostatic separation was performed using a lab-prototype corona belt separator (see [ 28 ] for details) that can be seen as a smaller-scale version of the electrostatic drum separator widely used in plastics and minerals processing industries. The voltage of the corona discharge was set to 25 kV, and the sorted particles were collected in three places: (i) on the side of the conveyor near the electrode for the particles blown by the ionic wind generated during the discharge (fraction FF-1-A), (ii) on the support housing the electrode generating the corona discharge, and (iii) at the end of the conveyor.…”