Equilibrium, Kinetic, and Thermodynamic Studies of Azo Dye Adsorption from Aqueous Solution by Chemically Modified Lignocellulosic Jute Fiber

Abstract

The lignocellulosic biomass jute fiber (JF) was chemically modified with polyphenolic tannin in aqueous medium by epoxy activation under mild conditions and applied as a potential adsorbent for the removal of Congo Red, a model azo dye, from aqueous solution. The virgin and tannin-modified JF samples were characterized by solid-state nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy. Within the studied range of dye concentrations, the adsorption equilibrium was found to follow the Langmuir isotherm model well, with R 2 > 0.99. The rate of adsorption of the dye onto treated JF was very high, and equilibrium was attained within 15−30 min of contact. The efficiency of modified JF for the spontaneous and exothermic adsorption of azo dye is attributed to the copious availability of hydroxyl and other polar functional groups on the fiber surface. The present adsorption studies of azo dye from aqueous solution revealed the potential of modified JF to be utilized as an alternative, inexpensive, and environmentally benign adsorbent for water purification.

CaCO3-decorated cellulose aerogel for removal of Congo Red from aqueous solution

“…The rate constant (k 1 and k 2 ) of both nonlinear kinetics models decreased as the initial CR concentration was increased. This can be attributed to the greater competition of dye molecules to access surface-active sites of the aerogel at higher CR concentration (Roy et al 2013). Overall, the pseudo-second-order model fits the experimental data better than the pseudo-first-order model, suggesting that the adsorption of CR involves chemisorption via valency forces through sharing or exchange of electrons between the adsorbent and dye molecules (Ho and McKay 1999).…”

“…3, the adsorption decreased upon increase of temperature, suggesting that the adsorption of CR onto the aerogel is exothermic in nature. This phenomenon may be due to weakening of the physical interaction at high temperature, such as hydrogen bonds and van der Waals force, between the CR and the aerogel (Roy et al 2013). Besides, the solute molecules show an inclination to escape from the solid phase and reenter the liquid phase due to increased mobility at high temperature (Roy et al 2012).…”

“…Azo dyes are difficult to decompose via biodegradation and photocatalysis due to their complex and stable aromatic molecular structures (Zhang et al 2011). Therefore, many recent studies have proposed that adsorption could be an alternative method for removing azo dyes from aqueous solution using various types of adsorbent (Dawood and Sen 2012;Mane and Babu 2013;Roy et al 2013).…”

Removal of methylene blue from water by cellulose/graphene oxide fibres

“…It is obvious that the removal percentage increases with increasing CGO dosage as a result of increased available adsorption active sites and surface area. [26] However, not all of the active sites on adsorbent can be occupied by MB molecules at the higher dosage of the CGO fibres, so the adsorption capacity decreases as the adsorbent dose increases.…”

Adsorção Em Meio Aquoso Do Corante Azo Ponceau 4r Sobre Sílica Gel Organofuncionalizada Com Aptes

“…Ademais, os processos de adsorção têm se mostrado muito eficientes e economicamente viá-veis no tratamento de efluentes contendo corantes azoicos (ABRAMIAN; EL-RASSY, 2011;AHMAD;HA-MEED, 2010;CESTARI et al, 2009;GUPTA et al, 2011;ROY;ADHIKARI;MAJUMDER, 2013;SHIR-MARDI et al, 2012;WANG, 2012). As principais vantagens dos processos adsortivos no tratamento de efluentes coloridos são os menores investimentos relativos, simplicidade de projeto e operação, não suscetibilidade a compostos tóxicos gerados, e facilidade de recuperação do adsorvente, como também dos compostos adsorvidos (MAHMOODI et al, 2014;MITTAL et al, 2009;SHARMA et al, 2011;ZHANG et al, 2015).…”