Efficient Removal of Toxic mMetal Ions (Pb(II) and Hg(II) Ions in Single Component Systems by Adsorption on Romanian Clay Material

Bianca Azamfire,Dumitru Bulgariu,Laura Bulgariu

doi:10.37358/rc.20.7.8223

Abstract

In this study, a local natural clay material was used for the efficient removal of Pb(II)ions and Hg(II) ions from aqueous media, in batch system. The adsorptive potential of clay material was testes at different initial solution pH, adsorbent dosage, contact time and initial heavy metal ions concentration and room temperature (20  2C). The highest adsorption efficiency of clay material was found at initial pH of 7.0 in case of Pb(II) ions, and 2.0 in case of Hg(II) ions, while the adsorbent dosage had the same value (4 g/L) for both metal ions. The adsorption equilibrium is very fast and was reach within 10 min. The modelling of experimental data showed that the adsorption processes followed the Freundlich isotherm model and pseudo-second order kinetic model. Detailed analysis of the experimental data indicate that the retention of Pb(II) and Hg(II) ions from aqueous solution on clay materials involves two processes, one of adsorption and the other of precipitation, whose succession depends on the speciation form of the metal ion in aqueous solution. However, the high adsorption capacity and short contact time are important characteristics which suggest the potential use of this clay material in environmental remediation processes.

Highlights

The high content of heavy metals in industrial wastewater represents a significant hazard to the quality of life of people around the world, mainly due to their non-biodegradability and their tendency to accumulate through the food chain
Effect of initial solution pH The initial solution pH is one of the most important parameters that affect the efficiency of the adsorption processes on clay materials [21, 22], mainly because it is responsible for both the speciation form of metal ion in aqueous solution, and the dissociation of functional groups from adsorbent surface
A local natural clay material was used for the efficient removal of Pb(II) and Hg(II) ions from aqueous solution

Summary

Introduction

The high content of heavy metals in industrial wastewater represents a significant hazard to the quality of life of people around the world, mainly due to their non-biodegradability and their tendency to accumulate through the food chain. The presence of toxic heavy metal ions, such as Pb(II), Hg(II), Cd(II), Cr(VI), As(III/V), etc., in water sources, is considered a major risk factor, which affect both the human health and the quality of ecosystems. The presence of such metal ions in ground and surface waters should be avoided over a maximum concentration limit, in accordance with the recommendations of the World Health Organization [3]. The main sources of water pollution with such toxic metal ions are the industrial effluents, resulted from various industrial sections (such as electroplating, fertilizers manufacturing, batteries manufacturing, paints fabrications, etc.) [4,5,6]. Incomplete or inefficient treatment of these effluents during technological processes, followed by their discharge into the environment are mainly responsible for the contamination of water sources with this kind of pollutants. Finding a suitable treatment process, customized for each type of wastewater, is still a priority in current environmental research [6, 7]

Methods

Results

Conclusion