Nanocellulose-based Hydrogels: Preparation Strategies, Dye Adsorption and Factors Impacting

The improper disposal of dyes without any prior treatment is one of the main causes of water pollution around the globe. Since dye-contaminated water contains a variety of hazardous elements, which may harm the aquatic ecosystem, impact the aquatic organisms and ultimately enter the food web chain. The most effective ways to recycle dye-contaminated waste water are adsorption, electrolysis, advanced oxidation, etc. Out of these techniques, adsorption strategy, due to its superior physico-chemical features, has been preferably employed for treating polluted water. In this review article, the potential of pure nitrocellulose (NC) hydrogel, metal/metal oxide or photo-adsorbents-based, metal-organic-framework supported, surface functionalized, bio-materials filled NC-based hydrogels for dyes adsorption has been thoroughly reviewed. The impact of different factors such as pH, time, temperature and filler/additives on dye adsorption/degradation capability of NC-based adsorbents, and kinetic and isotherm data of dye adsorption has been assessed systematically. Further, the influence of different eluents on the recycling ability of various NC- based hydrogels has also been fully assessed.