Adsorption of inorganic anionic contaminants on surfactant modified minerals

Abstract

Organo-mineral complexes were obtained by treatment of aluminosilicate minerals (zeolite, bentonite and diatomaceous earth) with a primary amine (oleylamine) and an alkyl ammonium salt (stearyldimethylbenzyl ammonium chloride). The modification of the zeolite surface was carried out in two steps. The first step was treatment of the zeolite with 2M HCl. This acid treatment of the zeolite increased its affinity for neutral molecules such as surface-active amines. The second step of the modification was the adsorption of oleylamine on the acid treated zeolite. Four types of organo-mineral complexes were prepared and their anion adsorption properties were compared to those of organo-zeolite. The adsorption of sulphate bichromate and dihydrogenphosphate anions on the organo-mineral complexes was investigated. The anion adsorption measurements showed that the most efficient adsorbent for anion water pollutants was the primary amine modified H+-form zeolite.

Surface modified zeolite, a novel carrier material for Azotobacter chroococcum

“…CZAs basically possess a negatively charged surface compensated by the presence of exchangeable cations at the aluminosilicate surface. A variety of cations can be adsorbed on zeolites by the cation exchange mechanism (Vujakovic et al 2003). The adsorption of cells was carried out at pH 7.0.…”

Removal of chromate from wastewater using amine-based-surfactant-modified clinoptilolite

“…However, the negative charge can be tuned by surface modification with either strong acids or with long-chain organic cations such as surfactants. Such surface treatments not only enhance the potential for anion exchange, but also modify the charge, composition, texture and structure, significantly (Vujakovic et al 2000(Vujakovic et al , 2003Wang and Peng 2010). Surfactant-modified zeolites (SMZs) have been suggested for remediation of wastewaters polluted with several organic pollutants, such as phenolic compounds (Lin and Juang 2009), dyes (Xie et al 2013) and heavy metal ions (Wang and Peng 2010).…”

“…At or below the critical micelle concentration (CMC), the amine head group of the surfactant is strongly bound with hydronium ions on the external surface via Coulombic forces and thus formation of a monolayer or hemimicelle occurs. On the other hand, as surfactant loads beyond CMC are provided, hydrophobic tails of surfactant molecules are oriented to form bilayer or admicelle structure (Vujakovic et al 2003;Wang and Peng 2010;Yariv and Cross 2002). The excess positive charge accumulated on the clinoptilolite surface improves the affinity for inorganic anionic pollutants, such as chromate ions, through the mechanism of replacement of counter ions (Xie et al 2013) (Fig.…”

“…The advancement in uptake capacity ranged between threefold and 20-fold depending on the compositional and textural properties of the raw material and more importantly, on the extent of surfactant loading (Leyva-Ramos et al 2008;Zeng et al 2010;Bajda and Klapyta 2013). An alternative modification route involving primary amine surfactants was proposed by Vujakovic et al (2000Vujakovic et al ( , 2003Vujakovic et al ( , 2004) who pretreated zeolites with strong acidic or basic agents to form a stable surface coverage and to obtain strong sites for anion precipitation. Since the surface precipitation is dominant mechanism for Cr(VI) adsorption, modification of strong acid-treated clinoptilolites with primary aminebased surfactants is an appropriate method to prepare high-performance Cr(VI) adsorbent (Vujakovic et al 2003).…”

Removal of Cadmium By Natural and Surfactant-Modified Mexican Zeolitic Rocks in Fixed Bed Columns

“…To increase the ability of zeolites to remove nonpolar and anion water pollutants, it is necessary to modify their surface. The negative charge in the crystal structures of zeolites make them suitable for surface modification by long chain cationic surfactants (Vujacović et al 2003), like hexadecyltrimethylammonium bromide (HDMTABr), surfactant modified zeolites can be used for the removal of various types of pollutants, like nonpolar organic compounds which are pollutants of priority concern that enter water bodies through discharge from petrochemical, pharmaceutical and other chemical manufacturing processes (Juang et al 2004); together with some heavy metals at different concentrations that could be simultaneously removed by surfactant-modified zeolites. As well as many ground waters which are polluted with a complex mixture of organic and metallic contaminants (Lin et al 2006).…”