Kinetics and Isotherms Studies of the Adsorption of Hg(II) onto Iron Modified Montmorillonite/Polycaprolactone Nanofiber Membrane

Hg(II) ions from mining and urban runoffs can easily contaminate various water sources due to their high solubility in water. Due to its simplicity and viability, adsorption was utilized to treat Hg( II)-contaminated water. An adsorbent was fabricated by immobilizing Fe-modified montmorillonite particles in polycaprolactone through electrospinning. The SEM images of the fabricated membrane showed a nanofiber network with fiber diameter ranging from 96 nm to 569 nm and an average of 198 nm. The adsorption behavior of the fabricated membrane was investigated using kinetics and isotherm models. It was found that the adsorption of Hg(II) ions onto the membrane follows a pseudo-second order model and was best described by the Freundlich isotherm. The adsorption capacity was found to increase with increasing contact time and with increasing initial Hg(II) concentration, with the highest adsorption capacity of 14.25 mg/g. The sorption energy was calculated using the Dubinin-Kaganer-Radushkevich isotherm, which obtained a value of -2.68 kJmol(-1) suggesting that the type of adsorption was physisorption.