Adsorption Equilibrium and Kinetics of Reactive Black 5 and Reactive Red 239 in Aqueous Solution onto Surfactant-Modified Zeolite

Abstract

The adsorption of Reactive Black 5 and Reactive Red 239 in aqueous solution on cetyltrimethylammonium bromide (CTAB)−zeolite was studied in a batch system. The natural zeolite and CTAB-modified zeolite were characterized by FT-IR and SEM analysis. Experiments were performed at different conditions such as initial dye concentration, contact time, temperature, and pH. CTAB modification covered the zeolite surface with positive charges, and the adsorption capacity of zeolite increased. The adsorption capacity of Reactive Red 239 was found to be two times higher than Reactive Blue 5 due to the hydrophilicity of the dye molecules. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms at different temperatures, and the Freundlich agrees very well with the experimental data. The pseudo-second-order model provided a very good fitting (R 2 > 0.992) for the two anionic dyes. The calculated maximum adsorption capacity (q e,calcd) increased with increasing initial dye concentration, but there is no linear relationship with pH and temperature. Thermodynamic parameters such as change in free energy (ΔG 0), enthalpy (ΔH 0), and entropy (ΔS 0) were also determined.

Experimental Study to Remediate Acid Fuchsin Dye Using Laccase-Modified Zeolite from Aqueous Solutions

“…Hence, the adsorption of AFD on LMZ is chemical in nature. The positive values of ΔSº indicate good affinity of the anion exchangers for AFD molecules and show an increase in the degree of freedom for the adsorbed species [55,[56][57][58].…”

Fixed bed column adsorption of ACID Yellow 17 dye onto Tamarind Seed Powder

“…As a result, natural waste products and plants have increased considerably during the past few years for pollution control applications (Kumar et al, 2009). These natural materials such as sawdust (Dorris et al, 2000), alunite (Ozacar and Sengil, 2003), fly ash (Rubio et al, 2008), and zeolite (Wang et al, 2006;Karadag et al, 2007) have been utilised to remove dye from aqueous solution. Adsorption in column (or in fixed-bed adsorber) is the most common and efficient way for purification of wastewater.…”

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