Environmental role of modified zeolite minerals in mercury removal in water and wastewater : Recoverability with maximum removal of mercury ions

The natural clinoptilolite zeolite was treated with NaOH and heat. The modified zeolite was then investigated by Field-emission Scanning Electron Microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and BET techniques. The modified zeolite managed to remove mercury ions up to 95%; while raw zeolite showed the maximum Hg removal ability of 35%. Also, the modified zeolite was reused seven times with stable adsorption of mercury ions. Based on the kinetic studies, the adsorption of mercury ion by modified zeolite follows the pseudo-second order model. Moreover, the experimental data were better fitted with Langmuir isothermal model than Freundlich. The removal of toxic mercury ions could serve as a useful solution for today's environmental issues.