Modification of kaolinite clay using benzyltriethylammonium chloride as a surfactant: Preparation and characterization

Hana Meftah Elgubbi,Siti Salhah Othman,Farah Wahida Harun

doi:10.14419/ijet.v9i4.31088

Hana Meftah Elgubbi, Siti Salhah Othman + Show 1 more

Open Access

https://doi.org/10.14419/ijet.v9i4.31088

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Abstract

Natural kaolinite clay from Perak, Malaysia with cation exchange capacity (CEC) of 2.5 meq/100g was modified using cationic surfactant, benzyltriethylammonium chloride (BTEA-Cl), at 0.5, 1.0, 1.5 and 2.0 times the CEC. A number of techniques, namely energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption were then used for characterization of the kaolinite and/or organo-modified kaolinite clays. The presence of alkyl groups as a result of successful intercalation of cationic surfactant within the organo-kaolinite layers of the clay was exhibited by the FTIR spectra. The SEM microphotographs exhibited good dispersion of the natural clay particles and slight agglomeration in the organo-modified clay particles. XRD patterns showed that the d001 spacing of the natural kaolinite clay increased from 7.12 Å to between 7.20 - 7.34 Å for the organo-modified clays. Following the BET nitrogen adsorption-desorption technique, all clay samples were of Type IV with narrow hysteresis loops. Surface areas of the clays showed drastic decrease from (25.34 m2/g) for natural kaolinite clay to between 5.90 - 13.11 m2/g for organo-modified clays. The results suggested that modification of natural kaolinite clay using cation surfactant had successfully occurred. The modification can therefore be further applied for alteration and improvement of the properties of natural clays for various industrial applications.

Highlights

Natural clays have been widely used in different scientific applications, because they can be found abundantly in nature and possess unrivaled characteristics
The value of cation exchange capacity (CEC) obtained in this study is in agreement with the findings by Al-Ani & Sarapaa [19], which suggested that the CEC values of kaolinite clays should be in the range of 1-10 meq/100 g clay
They suggested that lower CEC values are indications of pure kaolinite while higher CEC values indicate existence of additives as a result of successful modifications of the natural clay [20]

Summary

Introduction

Natural clays have been widely used in different scientific applications, because they can be found abundantly in nature and possess unrivaled characteristics. Kaolinite clay often shows lower surface area, and lower isomorphous substitution which result in lower adsorption capacity and lower cationic exchange ability [4]. In their natural state, the adsorption capacity of kaolinite clays can be modified by various methods to achieve desired chemical, surface, and structural characteristics for use in different industrial applications. The charge is balanced by alkali metal and alkaline-earth-metal cations such as K+, Na+ and Ca2+ The substitution of these inorganic cations by quaternary ammonium cations such as benzyltriethylammonium and hexadecyltrimethylammonium at the exchangeable sites results in formation of organoclay derivatives (Scheme 1) [2, 11]. Effectiveness of the cationic surfactant in modifying the surface of the clay for enhanced adsorption capacity of kaolinite clay was characterized by using XRD, FTIR, SEM and BET

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Conclusion