ADSORPTION OF CATIONIC DYE FROM AQUEOUS SOLUTION USING COMPOSITE CHICKEN EGGSHELL - ANTHILL CLAY: OPTIMIZATION OF ADSORBENT PREPARATION CONDITIONS

Adeyinka Sikiru Yusuff

doi:10.14311/ap.2019.59.0192

Abstract

A composite adsorbent was prepared from anthill and eggshell mixture, using an incipient wetness impregnation method and it was used for an adsorption of cationic dye (methylene blue, MB) from an aqueous solution. The effects of three preparation parameters including calcination temperature, calcination time and mixing ratio of eggshell to anthill on the MB uptake were investigated using the central composite design (CCD) of response surface methodology (RSM). A quadratic model was developed to predict the response with a high accuracy. The optimal adsorbent sample was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray fluorescence (XRF) spectroscopy. The obtained results revealed that the calcination temperature significantly affected the MB adsorption. The optimum MB uptake of 23.87 mg/g was achieved under the optimum conditions including a calcination temperature of 823.45 °C, calcination time of 3.54 h and eggshell/anthill mixing ratio of 1.89:1. A detailed characterization of an optimal adsorbent sample confirmed the presence of pores, active functional groups and various molecular adsorption sites on its surface. Equilibrium adsorption isotherms and kinetics were also studied and it was revealed that the isotherms and kinetics data fitted well to the Freundlich model and pseudo-second-order kinetics model, respectively.

Highlights

The generation of wastewater containing dye by textile industry has become an issue as its release into the environment usually leads to water pollution
The correlation between the actual and predicted responses was evaluated by a correlation coefficient (R2) and the value obtained (R2 = 0.9409) implies that the predicted values agreed excellently well with the experimental values. This indicates that only 94.09% of the total variations for the methylene blue (MB) uptake are described by the model, while only about 5.91% of the variation is not explained by the model
The process conditions for the preparation of the composite eggshell-anthill clay (CEAC) adsorbent developed for the MB adsorption from an aqueous solution were optimized

Summary

Introduction

The generation of wastewater containing dye by textile industry has become an issue as its release into the environment usually leads to water pollution These effluents contain a significant amount of basic dyes that are harmful to human beings and aquatic species. Treatment of industrial effluents, which contain dyes, is being achieved by the Fentonbiological method, ultrafiltration, ion exchange membrane, chemical precipitation, electrochemical degradation, photocatalytic process and adsorption [3,4,5,6,7,8] Among these treatment methods, adsorption process is found to be efficient, because most dyes are difficult to breakdown biologically, can be removed by porous solid material called adsorbent [1]. Researches have proven that adsorbents, such as alumina, silica gel, commercial activated carbon and molecular sieves, are effective for the removal of dyes from wastewater [9, 10] These adsorbents are expensive, making the search for alternative adsorbents necessary. Such alternatives could be sourced from agricultural waste/biomass [11, 12], naturally occurring materials [13], microorganism [14] and industrial waste [15]

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Conclusion