Removal of Supranol Yellow 4GL by adsorption onto Cr-intercalated montmorillonite

Cr(III)-intercalated montmorillonite was utilized as an adsorbent for the removal of the organic pollutant, Supranol Yellow 4GL, a synthetic dye used for chemical fibres. The material was prepared by the reaction of Na montmorillonite with a base-hydrolyzed solution of Cr nitrate salt (OH −/Cr 3+ molar ratios of 2). XRD data showed that the interlayer spacing ( d 001) of montmorillonite was increased from 12.35 to 23.06 Å. The kinetics and mechanism of the adsorption of the acid dye, Supranol Yellow 4GL, on Cr(III)-intercalated montmorillonite was investigated. The equilibrium time was reached within 30 min. The process follows pseudo-second-order rate kinetics. The Langmuir isotherm described the adsorption data over the concentration range (20–160 mg/l). The separator factor R L revealed the favourable nature of this adsorption process. Also, the thermodynamic parameters such as Δ S°, Δ H°, Δ G° were determined.