Banana Rachis CNC/Clay Composite Filter for Dye and Heavy Metals Adsorption from Industrial Wastewater

Abstract

This study demonstrates a successful processing and utilization of banana rachis cellulose nanocrystals (CNCs) dispersed clay composite filter which is capable of adsorbing dye and heavy metal ions namely Pb(II) and Cr(III) from industrial wastewater. The composite of different compositions was prepared by dispersing the cellulose nanocrystals, obtained by acid hydrolysis of banana rachis fibres, within the tri-ethyl amine treated clay. The CNC and treated clay were characterized by Fourier transform infrared (FTIR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM) analyses. Industrial wastewater containing a basic yellow2 dye and two heavy metal ions, Pb(II) and Cr(III), was passed through the prepared filters set in a column. The dye and metal ions adsorption capability of the filters were analyzed by determining the dye and metal ions concentration into the water before and after passing through the composite filter. The concentration of dye and metal ions in water was determined by a UV-visible spectrophotometer and an atomic absorption spectrophotometer, respectively. It was found that the dye adsorption capacity of the composite filters was about 50 mg per gram of composite as well as Pb(II) and Cr(III) ions adsorption capacities of the composite filters were ˃10.0 mg and ˃12.4 mg respectively per gram of the composite when CNC content in the composite was ˃30 wt.%. It was also found that the metal ions adsorption capability of the composite filter was improved with increasing CNC content in the composites.