Removal of the Textile Dye Indanthrene Olive Green from Aqueous Solution Using Chitosan

Abstract

ABSTRACT:The kinetics and equilibrium of the adsorption of Indanthrene Olive Green (IOG) from aqueous solution onto chitosan have been investigated. The chitosan was characterised in terms of its average degree of de-acetylation (DD) and by XRD, TGA/DTG, IR, SEM and specific BET surface area methods. Batch adsorptions experiments were carried out at different pH values and dye concentrations. It was found that the adsorption process was favoured by acidic pH conditions (4.0-6.0). The adsorption followed second-order rate kinetics and the experimental equilibrium data followed the Langmuir isotherm, thereby suggesting that chemisorption might be the major adsorption mode. Such adsorption also occurred on chitosan fibres, although to a significantly lower extent than on crushed chitosan. The corresponding thermodynamic parameters (∆G 0 , ∆H 0 and ∆S 0 ) were calculated. The positive values obtained for ∆H 0 (161.7 kJ/mol) and ∆S 0 [559.9 J/(mol K)] suggest that the adsorption process was endothermic, with the randomness of the system increasing during the adsorption process. A simplified adsorption model has also been proposed.

Degradation of organic compounds in a fenton system based on chitosan/Fe0/Fe2O3 composites: a theoretical and experimental study

“…The chitosan pK a is 6.4, then the net charge on its surface can be positive, neutral or negative, depending on pH. Therefore, at pH 6 the free amino groups in the chitosan molecule are protonated, favoring electrostatic attraction between chitosan and the reactive red dye, because they have opposite charge [44]. On the other hand, the adsorption process at pH 6 for hybrid material was low compared to the Fenton process (Fig.…”

“…9a). According to Chaves et al [44], these groups are those mainly responsible for the adsorption process in chitosan. Therefore, the presence of iron bonded in the groups could hamper the adsorption.…”

“…Therefore, the presence of iron bonded in the groups could hamper the adsorption. It is important to mention that the adsorption process consists only of conventional phase separation with the consequent problem of the final disposal [44,45]. Thus, the association between chitosan as catalyst support and iron species as the catalyst active phase is able to perform organic oxidation and simultaneous removal of hydrocarbons.…”

Synthesis and Properties of Cellulose-Based Macroporous Adsorbents

“…Macroporous adsorbents are generally prepared from cross-linked polymers derived from or modified with polystyrene, poly(methyl acrylate), chitosan, polypeptides, silica or other materials (Chaves et al 2009;Chiou et al 2004;Li et al 2009;Pi et al 2008;Qiao et al 2010;Weaver and Carta 1996). Cellulose, the most abundant renewable resource on Earth, is likely to become the main chemical resource in the future.…”