Application of porous membrane bag enclosed alkaline treated Y-Zeolite for removal of heavy metal ions from water

Abstract

In this work, an alkaline treated mesoporous faujasite-type ultrastable Y zeolite sorbent was employed for removal of heavy metal ions from water. The characterization of the sorbent material was performed using Fourier Transform Infrared spectroscopy, x-ray diffraction, adsorption analyzer, and field‐emission scanning electron microscopy. It exhibited distinct textural properties with surface area of 720 m2 g-1, pore volume of 1.00 cm3 g-1 and average pore diameter of 15 – 31 nm. To evaluate its potential for removal of heavy metals from water, the sorbent material (25 mg) was packed inside a porous polypropylene membrane bag via heat-sealing. This packing provides effective protection of the sorbent from the extraneous matrix in the samples and easy phase separation after completion of the removal process without requiring the steps of centrifugation and filtration. For removal process, the sorbent containing bag was immersed in 20 mL of the sample and agitated for 20 min using a shaker at a speed of 1200 rpm. It resulted in transfer and adsorption of heavy metals on the sorbent inside the bag. The adsorption capacities of 4.39, 3.48, and 1.15 mg g-1 were obtained for chromium (III), lead (II), and cadmium (II) respectively. Regeneration of the sorbent and elution of heavy metal ions was achieved by dipping the sorbent enclosed bag in 2 mL of 1 M HNO3 and assisting through sonication. The pseudo-second order kinetic and Freundlich isotherm were found to fit the adsorption data, and adsorption process was found to be endothermic. This method has great potential as an alternative to conventional methods for removal and analysis of heavy metal ions in water samples.