Gas-assisted low-field magnetic separation for large scale continuous magnetic bio-separation process

Abalone shell-based magnetic macroporous hydroxyapatite microspheres with good reusability for efficient dye adsorption

Azo dye methyl orange (MO) and shell rotting cause great environmental pollution. Most of the common dye adsorbents are difficult to produce, not environmentally friendly and it is always difficult to utilize the shell resources effectively. In this study, shell-based economical and environmentally friendly magnetic hydroxyapatite microsphere adsorbents (Fe3O4 @SiO2/HAP) were developed for the removal of MO from simulated wastewater by sol-gel and hydrothermal synthesis methods. The effects of solution pH, initial concentration, adsorption time and system temperature on the adsorption effect were investigated, and the repeat recovery performance was explored. The equilibrium adsorption data follow the Freundlich isotherm and pseudo-second-order kinetic curves, and the analysis indicates that the adsorption process is spontaneously exothermic. The adsorption capacities of MO were up to 94.48% and 88.94%, under the acidic environment of pH = 4, respectively, and had good recycling performance. The results provide a high-value utilization pathway for waste shell resources and focus on the removal of azo dyes. This is expected to provide new development ideas for the environmental hazards caused by acid dye wastewater discharged into rivers and oceans, as well as the problems of soil pollution and resource waste caused by weathering and corrosion of shells.

Magnetic Nanoparticles for Protein Separation and Purification

Proteins are essential for various functions such as brain activity and muscle contraction in humans. Even though food is a source of proteins, the bioavailability of proteins in most foods is usually limited due to matrix interaction with other biomolecules. Thus, it is essential to extract these proteins and provide them as a nutraceutical supplement to maintain protein levels and avoid protein deficiency. Hence, protein purification and extraction from natural sources are highly significant in biomedical applications. Chromatography, crude mechanical disruption, use of extractive chemicals, and electrophoresis are some of the methods applied to isolate specific proteins. Even though these methods possess several advantages, they are unable to extract specific proteins with high purity. A suitable alternative is the use of nanoparticles, which can be beneficial in protein purification and extraction. Notably, magnetic iron and iron-based nanoparticles have been employed in protein extraction processes and can be reused via demagnetization due to their magnetic property, smaller size, morphology, high surface-to-volume ratio, and surface charge-mediated property. This chapter is a summary of various magnetic nanoparticles (MNPs) that can be used for the biomolecular separation of proteins.