Diphosphonium ion-exchanged montmorillonite for Telon dye removal from aqueous media

• Published in: Applied clay science Vol. 50; no. 3; pp. 354 - 361
• Main Authors: Makhoukhi, B., Didi, M.A., Moulessehoul, H., Azzouz, A., Villemin, D.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01-11-2010; Elsevier
• Subjects: Adsorption; Cation exchanging; Chemical Sciences; Dye; Dyes; Earth sciences; Earth, ocean, space; Exact sciences and technology; Interlayers; Isotherms; Kinetics; Mineralogy; Montmorillonite; Oranges; Organic chemistry; Organo-montmorillonite; Phosphonium ions; Silicates; Telon; Dye; Kinetics; Adsorption; Telon; Phosphonium ions; Organo-montmorillonite; models; adsorption; diffusion; cation exchange capacity; ion exchange; isotherms; benzene; smectite; montmorillonite; pH; clay minerals; sheet silicates; silicates; ions; kinetics
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2010.08.026

Diphosphonium-intercalated montmorillonites were prepared via ion exchange using para, meta and ortho-bis(triphenyl phosphonium methylene)-benzene-dichloride (p-, m- and o-TPhPMB) in quantities not exceeding the cation exchange capacity. Adsorption tests applied to Telon dyes (Red, blue and orange) revealed a significant increase of the maximum adsorption capacity from ca. 11-26 to 110-160
mg.g-1 after intercalation. This improvement was explained by an increased organophilic character towards the organic dyes investigated. The highest adsorption level was noticed for Telon-orange dye on the para-diphosphonium organo-Mt, presumably due higher interlayer space and better diffusion. Dye adsorption turned out to strongly depend on pH, and low pH was found to increase the amount of adsorbed dyestuff. The dye adsorption was exothermal, and obeyed preferably pseudo first-order model for all three dyestuffs, but the process kinetics appeared to change over time. The adsorption isotherms were discussed in terms of Langmuir and Freundlich models.
► Montmorillonite intercalation by diphosphonium ions promotes Telon dye adsorption. ► Acidic pHs favor dye adsorption, but induce also slight dealumination. ► Dealumination enhances dye adsorption by generating new terminal [MtOH
2]
+ sites. ► Telon-orange adsorbs ca. two times faster than Blue and Red Telon-dyes. ► Telon dye adsorption is an exothermal adsorption.