Functional Chitosan Derivative and Chitin as Decolorization Materials for Methylene Blue and Methyl Orange from Aqueous Solution

• Main Authors: Abdelkader Labidi, Asier M. Salaberria, Susana C. M. Fernandes, Jalel Labidi, Manef Abderrabba
• Format: Article
• Language: English
• Published: MDPI AG 2019-01-01
• Series: Materials
• Subjects: Chitin; chitosan; polyacrylamide; dyes; decolorization; desorption
• Online Access: https://www.mdpi.com/1996-1944/12/3/361

Dyes are classified as one of the major pollutants of water. They have negative impacts not only on environment but also on human health. In fact, wastewater that contains these harmful substances requires many types of treatments. Therefore, alternative methods and adsorption agents are needed. Herein, we propose to evaluate the decolorization of methylene blue (MB) and methyl orange (MO) as two models of soluble dyes from water using chitin and chitosan-graft-polyacrylamide. Furthermore, the applicability of these biomacromolecules as alternative adsorption agents, their sticking probability and desorption were also examined. Experimental parameters such as dye concentration, contact time, pH solution, adsorbent dosage and temperature were thoroughly examined for the grafted chitosan and chitin. The activation energy (<inline-formula> <math display="inline"> <semantics> <mrow> <msub> <mi>E</mi> <mi>a</mi> </msub> </mrow> </semantics> </math> </inline-formula>) and the thermodynamic variables (i.e., standard Gibb&#8217;s free energy (<inline-formula> <math display="inline"> <semantics> <mrow> <mo>&#916;</mo> <msup> <mi>G</mi> <mn>0</mn> </msup> </mrow> </semantics> </math> </inline-formula>), standard enthalpy (<inline-formula> <math display="inline"> <semantics> <mrow> <mo>&#916;</mo> <msup> <mi>H</mi> <mn>0</mn> </msup> </mrow> </semantics> </math> </inline-formula>), and standard entropy (<inline-formula> <math display="inline"> <semantics> <mrow> <mo>&#916;</mo> <msup> <mi>S</mi> <mn>0</mn> </msup> </mrow> </semantics> </math> </inline-formula>)) were determined using the Van&#8217;t Hoff and Arrhenius equations. The sticking probability (<inline-formula> <math display="inline"> <semantics> <mi>S</mi> </semantics> </math> </inline-formula>*) model for MB and MO removal by chitin and the chitosan derivative demonstrated that both dyes were successfully removed under the proposed conditions. Desorption studies of MB and MO showed the reusability of both materials, suggesting their application for removing dyes from aqueous solution.