Development of Activated Carbon from Cotton Fibre Waste as Potential Mercury Adsorbent: Kinetic and Equilibrium Studies

Jatindra N Bhakta,Yukihiro Munekage,Piyali Bhakta Majumdar

doi:10.1155/2014/176483

Abstract

The study attempted to develop the activated carbon of cotton fibre (ACCF) from cotton waste as a high Hg2+adsorbent media and characterize physicochemical properties using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and Hg2+adsorption kinetic by batch adsorption study with the function of contact time, solution pH, dosages of ACCF, and Hg concentration. The SEM-EDS study revealed that ACCF is composed of carbon (95.1%) and phosphorus pentoxide (4.9%). Obtained results of adsorption kinetics showed that 15 min of contact time is required to achieve the equilibrium state and wide range of pH (4.08–7) is favourable for maximum Hg adsorption. The Hg2+adsorption capacity showed a decreasing trend with increasing dose of ACCF, whereas a reverse response of adsorption capacity was pronounced with increasing Hg concentration. The data was well described by Freundlich isotherm model and determined the high Hg2+adsorption capacity of ACCF (169.2 mg/g). To our knowledge, the application of ACCF in removing Hg2+is the first study. High Hg2+adsorption capacity, economic feasibility, availability of cotton fibre waste, and simple preparation method concluded that it could be used as a novel low-cost and environmentally sound adsorbent media for removing high rate of Hg2+from aqueous phase.

Highlights

Mercury (Hg) is one of the top ten most toxic and hazardous pollutants in the Priority List of Hazardous Substances [1] for causing serious human and environmental health risks by bioconcentration, bioaccumulation, and biomagnification phenomena
The batch adsorption experiments clearly revealed the significant influence of various environmental process parameters on the Hg adsorption capacity of Activated carbon (AC) of cotton fibre (ACCF)
The study proposed that contact time 15 min and wide range of pH (4.08–7) are to be optimal for maximum Hg adsorption

Summary

Introduction

Mercury (Hg) is one of the top ten most toxic and hazardous pollutants in the Priority List of Hazardous Substances [1] for causing serious human and environmental health risks by bioconcentration, bioaccumulation, and biomagnification phenomena. Hg and its derivatives can be adsorbed through the gastrointestinal tract, skin, and lungs and it is recognized as dangerous and insidious poisons [2]. The toxic, nonmetabolic function, conversion of lower to higher toxic forms, bioaccumulation, and serious health disorders on animal systems are the significant criteria of Hg [2,3,4,5]. The severity of Hg toxicity was recognized in the late 1950s and 1960s because of an environmental tragedy in Minamata Bay, Japan, where hundreds of individuals suffered from mercury poisoning (Minamata disease) [6]. The US Environmental Protection Agency (EPA) estimated 630,000 newborns in America are at risk for unsafe levels of Hg exposure [7]

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