Adsorptive behaviour of nepheline syenite as a new adsorbent for removal of Ag (I) and Pb (II) ions from aqueous solution and industrial wastewater

Abstract

ABSTRACT The present study aims to assess the ability of nepheline syenite in removing the environmental pollution of Ag (I) and Pb (II).The characterisation of nepheline syenite was determined by SEM, BET, XRD, XRF and FTIR analyses. The batch system was carried out to examine the adsorption effect under the diverse amount of the nepheline syenite, the initial concentration of Ag (I) and Pb (II), the influence of contact time, and the pH of solution. The maximum Ag (I) and Pb (II) adsorption is achieved on 3 g of nepheline syenite at the pH value of 5.5, contact time of 90 min with an initial concentration of Pb (II) and Ag (I) 1000 mg/l. The equilibrium studies were examined based on two and three parameter models at different temperatures of 297, 303, 313 and 323 °K. The results fitted better with Freundlich model for Ag (I) adsorption at all temperatures and Pb (II) adsorption at lower temperatures (297 and 303°K). The maximum adsorption capacity for Pb (II) and Ag (I) ions were obtained 80.78 and 55.76 mg/g, respectively. The pseudo-second-order model exhibited the best fit with experimental data for both ions. Based on thermodynamic studies, the Ag (I) and Pb (II) adsorption onto nepheline syenite was exothermic, associative and non-spontaneous. Moreover, the low-cost nepheline syenite was applied to remove Ag (I) and Pb (II) ions from electroplating and battery recycling plant wastewaters which obtained promising results.