Synthesis of MnO2 on Activated Carbon and its Potential Application in the Adsorption of As(V) and Pb(II) in Aqueous Solutions.

Roberto Contreras-Bustos,Jaime Jiménez-Becerril,Melania Jimenez-Reyes,Bibiana Cercado-Quezada,E Manríquez-Reza

doi:10.17344/acsi.2017.3274

Abstract

The conditions for the synthesis of a material with MnO2 (OMD) on activated carbon (AC) were studied. These conditions were: reaction time, temperature, stirring speed, concentrations of AC, H2SO4, and O3 in solution, and particle size. Agglomerates on AC were observed by means of scanning electron microscopy (SEM) and microanalysis by energy dispersive spectroscopy (EDS) and revealed the presence of OMD deposited on the surface. The activation energy and the factor of frequency for the reaction were determined as Ea = 1.2 kcal/mol and A = 2.2. The value of Ea indicates that the precipitation of OMD on the AC was controlled by mass transfer in aqueous solution and the order of reaction was zero. The adsorption capacities of AC were q = 14 mg Pb(II)/g AC and q = 9.1 mg As(V)/g AC. Whereas, for the OMD/AC obtained in the following conditions: [AC] 1 or 2 g/L, particle size of AC of +0.59 mm, [H2SO4] 1 or 2 mol/L, 25 °C, stirring speed 600 rpm, and [O3] 1.35 mol/L, the adsorption capacities were q = 90.5 mg Pb(II)/g OMD/AC and 25.4 mg As(V)/g OMD/AC. Therefore, the fixing of OMD on the surface of the AC greatly improved the removal of both Pb(II) and As(V) from aqueous solutions.

Highlights

Studies on absorbent materials for natural and anthropogenic contaminant ions, in both surface water and groundwater, remain of interest
The present investigation proposes the synthesis of an adsorbent material, which consists of OMD supported by activated carbon (AC) to examine whether its physical and chemical characteristics are suitable for the adsorption columns used in water purification
There are significant deposits of OMD in the synthesized material at that temperature, the results indicate that the main factor responsible for the removal of Pb(II) is AC

Summary

Introduction

Studies on absorbent materials for natural and anthropogenic contaminant ions, in both surface water and groundwater, remain of interest. Arsenic and lead ions have notable deleterious effects on human health. In Mexico, their presence has been detected in aquifers, especially in the north of the country.[1] They cause various diseases including skin diseases, bone diseases and diseases in other vital organs. They can lead to death when high-dose exposure is continuous. It is important to find efficient alternatives for the removal of these ions from water and to reduce the risks to human health

Objectives

Results

Conclusion