Enhanced simultaneous adsorption of Cd(II) and Pb(II) on octylamine functionalized vermiculite

Cadmium (Cd) and lead (Pb) have been remained the topic of investigation for various research studies because of their adverse effects on human health, furthermore, they have toxic and non-biodegradable properties. In this study, vermiculite (VER) was functionalized with octylamine (OCT) to obtain a novel organoclay (OCT-VER) for enhanced simultaneous adsorption of Cd(II) and Pb(II) from aqueous solution. Adsorbents were characterized and parameters influencing on adsorption were also investigated. The adsorption of Cd(II) and Pb(II) by OCT-VER was monolayer and homogenous which was described well by Langmuir isotherm model. After modification, the affinities of OCT-VER towards both metal ions were enhanced. In single system, maximum adsorption capacities for Cd(II) and Pb(II) were improved from 45.245 and 102.289 mg.g(-1) to 69.595 and 184.603 mg.g(-1) while in binary system from 37.539 and 78.265 mg.g(-1) to 61.630 and 121.986 mg.g(-1), respectively. In adsorbent regeneration experiment of OCT-VER, the removal ratio was found approximate to 90 % even after 5 consecutive cycles, exhibiting good stability and easy regeneration potential. After studying thoroughly, ion-exchange and complexation properties were the main reaction mechanism. These findings suggested that the proposed low cost adsorbent was suitable and promising material for Cd(II) and Pb(II) adsorption in water.