A decade development in the application of chitosan-based materials for dye adsorption: A short review

The presence of dyes in the aquatic environment as a result of anthropogenic activities, especially textile industries, is a critical environmental challenge that hinders the availability of potable water. Different wastewater treatment approaches have been used to remediate dyes in aquatic environments; however, most of these approaches are limited by factors ranging from high cost to the incomplete removal of the dyes and contaminants. Thus, the use of adsorption as a water treatment technology to remove dyes and other contaminants has been widely investigated using different adsorbents. This study evaluated the significance of chitosan as a viable adsorbent for removing dyes from water treatment. We summarised the literature and research results obtained between 2009 and 2020 regarding the adsorption of dyes onto chitosan and modified chitosan-based adsorbents prepared through physical and chemical processing, including crosslinking impregnation, grafting, and membrane preparation. Furthermore, we demonstrated the effects of various chitosan-based materials and modifications; they all improve the properties of chitosan by promoting the adsorption of dyes. Hence, the application of chitosan-based materials with various modifications should be considered a cutting-edge approach for the remediation of dyes and other contaminants in aquatic environments toward the global aim of making potable water globally available.

Extraordinary Superhydrophobic Polycaprolactone-Based Composite Membrane with an Alternated Micro-Nano Hierarchical Structure as an Eco-friendly Oil/Water Separator

Extraordinary superhydrophobic polycaprolactone (PCL) composite membranes with an alternated hierarchical micro-nano structure were designed by addition of SiO₂ aerogel. The highest water contact angle (WCA) of 166.8 ± 1.5° was obtained when SiO₂ aerogel content was 0.5% (PCL/SiO₂-a0.5) in the PCL composite membrane, which was higher than other reported polymer-based membranes. SiO₂ aerogel lowered PCL composite membrane's surface energy. The triple curvature structure composed of microspheres, nanospheres, and nanofibers produced on PCL/SiO₂-a0.5 membranes endowed the excellent roughness of the surface. Also, the inner structure of the PCL/SiO₂-a0.5 composite membrane composed of micro-nano spheres, nanofibers, and microfibers increased the porosity of the separation membrane, which would provide more adsorption space. The PCL/SiO₂-a0.5 composite membrane as a separator for surfactant-stabilized emulsions of water-in-oil showed ultrahigh separation flux and efficiency. Meanwhile, the PCL/SiO₂-a0.5 composite membrane had an outstanding chemical resistance, self-cleaning ability, and good reusability. The composite membranes reported in this work as eco-friendly separation materials possessed all these characters in oil/water separation. This research proposed a very simple method to design eco-friendly high-efficiency separators through the construction of the alternated micro-nano hierarchical structure.

Removal of a cationic dye from aqueous solution by a porous adsorbent templated from eco-friendly Pickering MIPEs using chitosan-modified semi-coke particles

Porous materials prepared from high internal phase emulsions have been attracting much attention in recent years, but two major defects related to the high consumption of organic solvent and surfactants are always difficult to solve.

Co-modification of lignocellulosic biomass by maleic anhydride and ferric hydroxide for the highly efficient biosorption of methylene blue

Ferric hydroxide and microwave-assisted solvent-free esterification was applied in the modification of SBP to synthesize an efficient cationic dye adsorbent.