Hydrogel microparticles, generally accepted as significant green materials, have been widely used in chemical, biological, and biomedical fields owing to their excellent biocompatibility, biodegradability, and non-cytotoxicity. Among these, non-spherical hydrogel microparticles with diverse shape anisotropy have great potential in applications such as drug delivery, cellular interaction, micromotors, etc. Benefiting from their shapes, their functionalities in such fields cannot be satisfied by the typical spherical types. Recently, microfluidics with precise control and domination of fluids at microflow sizes has emerged as a powerful method for synthesizing shape-controllable hydrogel microparticles with good monodispersity and unique morphology. In this review, we tried to provide an overview of the production of non-spherical microparticles composed of green hydrogel materials, emphasizing the microfluidic approaches. Furthermore, a brief introduction to their current applications is also presented.

Global warming and climate change due to anthropogenic carbon dioxide (CO₂) have aroused significant concerns at the global scale due to rapid economic growth in industries and other fields. Therefore, CO₂ capture, use, and storage have become particularly important. In this review, general background and methods for CO₂ capture and separation, in particular, on ionic liquids (ILs)-based solvents and materials, are discussed. Comprehensive surveys of ILs for CO₂ absorption are presented, which focused mainly on experimental researches, and then the concept is extended to functionalized absorbents and recent developments for CO₂ capture. Major advantages and disadvantages of amines-based and ILs-based absorbents are discussed in this review. Solutions of traditional amines (MEA, MDEA, DEA, AMP, PZ, etc.) and ILs (conventional ILs, functionalized ILs, etc.) are summarized. Moreover, research progresses on CO₂ separation are also introduced focusing mainly on amines and ILs-based membranes (e.g. supported amines membranes, SILMs). Futhermore, the fixation of CO₂ into cyclic carbonates catalyzed by ILs (pure ILs, complex catalyst system with ILs, supported ILs, etc.) is summarized, clearly explaining the mechanism of CO₂ fixation with ILs. Finally, exploration of some recent studies about CO₂ capture and conversion by ILs and challenges for further progress are presented and related suggestions are put forward.