Studies on the adsorption of naphthalene and pyrene from aqueous medium using ripe orange peels as adsorbent

C.N Owabor,J.E Audu

doi:10.4314/gjpas.v16i1.62822

Abstract

The effectiveness of dried ground orange peels in adsorbing naphthalene and pyrene from an aqueous stream has been investigated in terms of variation in concentration, adsorbent dosage, agitation time and particle size. Experimental batch data was correlated by Freundlich and Langmuir isotherm models. The Freundlich isotherm best described the adsorption process as the adsorption data fitted well into the model. The adsorption capacity and energy of adsorption were obtained as 7.519mg/g and 0.0863mg-1, and 3.8168mg/g and 0.0334mg-1 for naphthalene and pyrene respectively. The adsorption from the aqueous solution was observed to be time dependent while equilibrium time was found to be 100 and 120 minutes for naphthalene and pyrene respectively. Adsorption increased with increase in adsorbent dosage and was maximum at between 5 to 7g for naphthalene and 6 to 8g for pyrene. The maximum adsorption was observed using a particle size of 2.0mm. The rate of adsorption using the first order rate expression by Lagergren for naphthalene and pyrene were 0.007 and 0.006 min-1 respectively. These results therefore suggest that naphthalene is more selectively adsorbed than pyrene using ripe orange peel as adsorbent.KEY WORDS: Naphthalene, Pyrene, Adsorption, Adsorbent, Ripe orange peels.

Highlights

The issues arising from oil spillages have become a subject of very serious concern for both the orange peels, a relatively low cost agricultural waste which is readily available in Nigeria, is advanced in this study
The results show that the adsorption of pyrene and naphthalene from an aqueous stream is dependent on the particle size used
From the results obtained it can be concluded that ripe orange peels which is regarded as waste materials can be used as adsorbent for the removal of polycyclic aromatic hydrocarbons like naphthalene and pyrene

Summary

Introduction

The issues arising from oil spillages have become a subject of very serious concern for both the orange peels, a relatively low cost agricultural waste which is readily available in Nigeria, is advanced in this study. The study examines the adsorptive capacity of the orange peels under the effect of varying government and non government organization because experimental conditions using the Freundlich and of the potential adverse effects on the quality of the Langmuir isotherms models. The Freundlich and Langmuir adsorption isotherms are two common isotherms used to describe discharge of organic compounds like polycyclic aromatic hydrocarbons arising from the process of refining crude oil or production of petrochemical products. Polycyclic aromatic hydrocarbons generally known as PAHs are highly lipophilic, being readily soluble in oil than water adsorption equilibria studies. The Langmuir adsorption isotherm on the one hand is (Luch, 2005)

Methods

Results

Conclusion