Emulsion hydrogel microbeads encapsulating extractants prepared by O/W/O double Pickering emulsions for the recovery of Cu(II) from water

Recent progress in oil-in-water-in-oil (O/W/O) double emulsions

“…Since the irreversibly adsorbed solid particles can function at the oil-water interface by controlling the wettability and contact angle of the solid colloidal particles, the Pickering emulsion possesses higher stability (resistance to deformation) than conventional emulsions for the long-term storage (Low et al 2020;Yu et al 2021). Yuan et al (2021) explored the preparation of stable O/W/O Pickering emulsions for the formulation of Pickering emulsion hydrogel microbeads entrapping copper extractants. Given the fact that the cross-contamination ratio (the degree of migration between inner and outer oil phases) of O/W/O Pickering emulsions could be reduced to <3% under pre-set conditions, it suggested that further improvement of the stability and preventing the cross-contamination between internal and external phases is possible.…”

“…Microscopy can be used to unveil the formation process of O/W/O emulsions, the morphology of droplets, the mean droplet size, and its variation, as well as the degree of filling. All these factors are closely related to the emulsion stability (Qin, Li, and Hu 2021;Ren et al 2021;Yuan et al 2021). By referring to a self-assembled visualization system, including microscopy, a high-speed camera, a computer, and a light source, Lu et al recorded the transient formation processes of single-core and multi-core O/W/O double emulsions and determined their filling degree by a co-flowing microfluidic device (Lu, Wu, and Liu 2017).…”

Current Status and Future Perspectives of Supports and Protocols for Enzyme Immobilization

“…In this perspective, the area of enzymatic biocatalysis has been very interested in this process, given the low costs of developing protocols and the high catalytic response offered by the emulsified catalytic derivative [264,[269][270][271]. This vehemence comes from the large "oil-water" interface area that allows biphasic reaction systems to have high efficiency in optimizing hydrogenation, oxidation processes, and enzymatic reactions [269,270,[272][273][274][275]. [268] presented a simple strategy for immobilization of the lipase of Candida sp.…”

One-Step Generation of O/W/O Double Pickering Emulsions Utilizing Biocompatible Gliadin/Ethyl Cellulose Complex Particles as the Exclusive Stabilizer

“…5 For instance, in the case of O/W/O emulsions, the primary oil-in-water (O/W) emulsion is first stabilized by a hydrophilic emulsifier under high shear conditions; subsequently, this O/ W emulsion is dispersed into a continuous outer oil phase using a lipophilic emulsifier. 6 The reverse procedure, following similar principles, is employed for the development of W/O/W emulsions. 7 Although the two-step process offers advantages in terms of incorporating and controlling encapsulation materials, the second emulsification step poses a risk of destabilizing the primary emulsion.…”

“…The conventional preparation of double emulsions typically involves a two-step emulsification process, which has been considered a standard procedure since its initial report . For instance, in the case of O/W/O emulsions, the primary oil-in-water (O/W) emulsion is first stabilized by a hydrophilic emulsifier under high shear conditions; subsequently, this O/W emulsion is dispersed into a continuous outer oil phase using a lipophilic emulsifier . The reverse procedure, following similar principles, is employed for the development of W/O/W emulsions .…”