Optimization of Heavy Metals Removal from Aqueous Solution Using Synthesized Chromic Oxide and Chromic Oxide – Lophira Alata Carbonized Sawdust Nanoparticles

J M Okuo ,Moses Okponmwense ,B Anegbe ,Ufuoma Ugbune

doi:10.7176/jnsr/10-2-06

Abstract

This research was designed to ascertain the removal efficiency of Cd 2+ and Pb 2+ ion in aqueous system with the use of chromic oxide nanoparticle (CN) and chromic oxide- lophiraalata carbonised sawdust nanocomposite (CLN) synthesized by co-precipitation and thermal degradation methods. The physicochemical characterization of the synthesized chromic oxide nanoparticle and chromic oxide- lophiraalata carbonised sawdust nanocomposite (CN and CLN) were evaluated using x-ray diffractograms (XRD), scanning electron microscope (SEM) and Fourier Transform infrared spectrophotometer (FTIR). The obtained CN and CLN were crystalline, amorphous, smooth and spherical in shape with very small particles inapparently soft agglomerates with a size of 7.7 and 12.05 nm respectively. The amount of Cd 2+ and Pb 2+ ions before and after treatment of the polluted water was evaluated using atomic absorption spectrometer (AAS). The adsorption property of CN and CLN was studied using isotherm models and Response Surface Methodology (RSM) Analysis. The isotherm models revealed that the adsorption process of Cd 2+ and Pb 2+ ions onto CN and CLN was a physical process (physiosorption), favorable and exothermic. The energy of affinity for Pb 2+ ions on both nanoparticles was higher. The response surface methodology analysis for CN revealed that the cadmium ions were slightly more adsorbed and removed from the heavy metal polluted water compared to lead ions. This observation was in agreement with the k F values obtained from Freundlich isotherm in which the k F value for cadmium ions (59.52) was higher than that of lead (51.99). However, the response surface methodology analysis for CLN revealed that the Pb 2+ ions were more adsorbed compared to Cd 2+ ions with optimum adsorption capacities of 191.50 and 66.20 mg/g respectively. These values also agreed with the K F values obtained from Freundlich isotherm. This implies that CLN was more effective in the removal of Pb 2+ ions. Keywords: Chromic oxide, Nanoparticle, Optimization, Response Surface Methodology, Isotherm DOI : 10.7176/JNSR/10-2-06 Publication date: January 31 st 2020

Highlights

Water is one of the most important resources for human life, despite its abundance on the earth, majority of the water bodies are polluted (Mohan et al 2011)
Characterization of Chromic Oxide Nanoparticle (CN) and CLN The scanning electron microscope (SEM) images of CL, CN and CLN are shown in Fig. 1a – 1c
Fig 1b: SEM Image of Chromic Oxide Nanoparticle (CN) The SEM showed that the surface of the carbonized Lophira alata (CLN) (Fig 1c) possesses rough surface morphology with some pores and has a fibre-like structure which is characteristic of agro- waste

Summary

Introduction

Water is one of the most important resources for human life, despite its abundance on the earth, majority of the water bodies are polluted (Mohan et al 2011). The parameters of polluted water vary widely and depend upon the source from which it is generated. They are pathogenic and non-pathogenic microorganisms, organic or inorganic. Different methods adopted for heavy metals removal from aqueous medium include membrane separation, coagulation, flocculation, chemical treatment, filtration and adsorption (Sadegh et al 2014). Information about using nanomaterials for adsorption of heavy metals in aqueous system in developing country is still at the preliminary stage. Nanoparticles characteristically have very high surface area www.iiste.org to volume ratios, which when compared to their bulk counterparts and their properties can vary dramatically under different electrical, photological, and thermodynamic conditions (Rathore et al 2012; Mahdi et al 2012). The objective of this study was to synthesize, characterize CN and CLN and evaluate the efficiency of CN and CLN in removing Cd2+ and Pb2+ ions from polluted system using isotherm models and response surface methodology

Objectives

Methods

Results