Chitosan adsorbents for dye removal: a review

Abstract

One of the most important decontamination techniques is considered to be adsorption. It is fast, simple, low cost with many opportunities to modify the initial materials after appropriate synthesis routes etc. Numerous adsorbent materials have been prepared in the last few years having as the ultimate scope to remove some pollutants especially from contaminated waters (effluents originating from industry). But the composition of each type of effluent varies. Dyes are some major components of industrial wastewaters. Chitosan (poly--(1 → 4)-2-amino-2-deoxy-D-glucose) is a nitrogenous (amino-based) polysaccharide which is produced in large quantities by N-deacetylation of (its source compound) chitin. The major advantage of chitosan is the existence of modifiable positions in its chemical structure. Modification of the chitosan molecule by (i) grafting (inserting functional groups) or (ii) crosslinking reactions (uniting the macromolecular chains with each other) leads to the formation of chitosan derivatives with superior properties (enhancement of adsorption capacity and resistance in extreme medium conditions, respectively). This review summarizes the important contribution of chitosan derivatives to the dye removal process by adsorption.

Dye removal by biosorption using cross-linked chitosan-based hydrogels

“…In the past two decades, these materials used as biosorbents have received much attention in water and wastewater treatment, mainly for metal chelation and dye removal Crini 2015;Kos 2016;Muya et al 2016;Kanmani et al 2017;Kyzas et al 2017;Nechita 2017;de Andrade et al 2018;Desbrières and Guibal 2018;El Halah et al 2018;Pakdel and Peighambardoust 2018;Wilson and Tewari 2018). Indeed, chitosan has an extremely high affinity for metals and metalloids and for many classes of dyes, including direct, acid, mordant and reactive.…”

Cross-Linked Chitosan-Based Hydrogels for Dye Removal

“…Indeed, chitosan has an extremely high affinity for metals and metalloids and for many classes of dyes, including direct, acid, mordant and reactive. In their comprehensive reviews, Crini (2015), Yong et al 2015, Kyzas et al (2017), Wang and Zhuang (2017), Desbrières andGuibal (2018), El Halah et al (2018) and Pakdel and Peighambardoust (2018) recently indicated that biosorption onto chitosan was a promising alternative to replace conventional adsorbents used for decolorization purposes, metal chelation or recovery, and organic removal. With nutraceuticals and cosmeceuticals, the water and wastewater treatment field seems to be the next market in the development of chitosan.…”

“…The reader is encouraged to refer to the original articles for information on experimental conditions. Crini (2015), Kyzas et al (2017), and Wang and Zhuang (2017) demonstrated that biosorption using non-conventional cross-linked chitosan hydrogels is an effective and economic method for water decolorization. These materials had an extremely high affinity for many classes of dyes commonly used in industry with outstanding biosorption capacities, in particular anionic dyes such as acid, reactive and direct dyes (Table 10.4).…”

“…type of functional groups and degree of grafting but also to textural properties (from microspheres to nanoparticles). An overview of the literature data shows that performances strongly depend on the type of material used (Crini 2015;Yong et al 2015;Kyzas et al 2017;Wang and Zhuang 2017;Desbrières and Guibal 2018). Indeed, each material has its specific application as well as inherent advantages and disadvantages in dye removal.…”

“…Amine groups are susceptible to ionization as a function of pH (pk a values in the range 6.3-6.5), that allow chitosan to form a polycation species. Hence, the protonated amine groups can form complexes with anionic species by electrostatic attractions and/or ion-exchange (Guo and Wilson 2012;Olivera et al 2016;Salehi et al 2016;Kyzas et al 2017; Subramani and Thinakaran 2017; Wang and Zhuang 2017; Karimi et al 2018). Figure 10.3 illustrates the mechanism of anionic dye adsorption by a cross-linked chitosan hydrogel under acidic conditions.…”