A study on the modification of Phu Yen diatomite to prepare an adsorbent for the removal of iron ions in water environment

Abstract

Natural diatomite was modified by manganese chloride. The characterization of natural and modified diatomite was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET) analysis techniques. The morphology of both types of diatomite was generally cylindrical in shape with the range of particle size of 2-3 µm in width and 10-17 µm in length. The chemical compositions of natural and modified diatomite were determined by Fourier transform infrared (FT-IR) and energy-dispersive X-ray analysis (EDX). The surface area of modified diatomite (157.667 m²/g) was higher than the surface area of nature diatomite (88.604 m²/g). The capacity of adsorbing Fe³⁺ ion onto natural and modified diatomite was determined by UV-VIS spectrometry. Langmuir isotherm was employed to describe adsorption equilibrium. The saturation capacities were 14.35 mg/g modified diatomite for iron ion, respectively, while value of 4.86 mg/g is obtained for natural diatomite.

Key words: Diatomite, modified, surface area, adsorption, isotherm.