On the Sorbent Ability and Reusability of Graphene-Oxide–Chitosan Aerogels for the Removal of Dyes from Wastewater

Abstract

One of the most persistent issues affecting people worldwide is water contamination due to the indiscriminate disposal of pollutants, causing severe environmental problems. Dyes are among the most harmful contaminants because of their high chemical stability and consequently difficult degradation. To remove contaminants from water, adsorption is the most widely used and effective method. In this work, we recall the results already published about the synthesis, the characterization and the use of porous graphene-oxide–chitosan aerogels as a sorbent material. Those systems, prepared by mixing GO sheets and CS chains, using APS as a cross-linking agent, and by further lyophilization, were further characterized using nano-computed tomography, supplying more understanding about their micro and nano-structure. Their sorbent ability has been investigated also by the study of their isotherm of adsorption of two different anionic dyes: Indigo Carmine and Cibacron Brilliant Yellow. Those analyses confirmed the potentialities of the aerogels and their affinity for those anionic dyes. Moreover, the possibility of regenerating and reusing the material was evaluated as a key aspect for applications of this kind. The treatment with NaOH, to promote the desorption of adsorbed dyes, and subsequent washing with HCl, to re-protonate the system, ensured the regeneration of the gels and their use in multiple cycles of adsorption with the selected water contaminants.

Gel based on modified chitosan for oil spill cleanup

“…Pollution of water bodies with various pollutants, such as heavy and radioactive metals, [1][2][3][4][5][6][7][8] dyes, 9 pesticides, 10 organic solvents, and oil products, 11 is a severe environmental problem. The discharge and leakage of oil and oil products in case of accidents on oil tankers and main oil pipelines cause significant damage to aquatic ecosystems and create significant economic losses.…”