Alkali-treated coir fibre-pith composite for waste water treatment

Abstract

Coir fibre and pith are eco-friendly material used in the preparation of composites. Coir fibre and coir pith were treated with sodium hydroxide to study the effect of alkali for prolonged exposure on its properties. Fibre and pith were treated with different concentrations of NaOH from 5% to 30% for 24 hours at room temperature. Alkali treatment removes the impurities and the expose the crystalline cellulose and to enhance the surface properties. The alkali-treated coir fibre and pith were characterized by Scanning electron microscopy for morphology, X-ray diffraction for crystallinity index, thermogravimetry for thermal stability, Fourier-transform infrared spectroscopy for structural changes. The chemical composition was analysed for both fibre and pith. Physical properties such as bulk density, particle density and porosity were determined for pith. After alkali treatment, the properties (physical and chemical) of the treated fibre (5% to 20%) has been enhanced. For coir pith the properties has been diminished. Untreated/treated coir fibre/pith filter (CFP) were developed to study the removal of heavy metal ions from the waste water, where untreated (CFP) as a control. The removal efficiency of the developed CFP filter for heavy metal ions were determined by Inductively coupled plasma - optical emission spectrometry (ICP-OES). 5% CFP filter exhibited higher efficiency for removal of heavy metal ions.