Synthesis, characterization, and evaluation of zeolite material for the removal of chromium (Cr³⁺) from contaminated water

Abstract

Zeolite crystals were synthesized by combining sodium silicate and sodium aluminate to form an aluminosilicate gel, which was then hydrothermally treated to produce the final product. The zeolite crystals were analyzed using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive x-ray diffraction (EDX), and Fourier Transform Infrared (FTIR) Spectroscopic Analysis. Batch adsorption tests and the atomic absorption spectroscopy with the synthetic zeolite demonstrated effective removal of chromium(III) ions from the contaminated water. During the treatment, various amounts of zeolite from 0.5 to 2.5 g were utilized, along with different concentrations of Cr(III) ions (10, 15, 20, 25, 30 ppm). The percentage of adsorption rose from 55.75 to 96.6% and fell from 98 to 88.3% in each of the stages. As the pH levels were adjusted between 1 and 11, the percentage of adsorption increased from 55 to 97%, with a significant rise at pH 7. The high percentage of adsorption in the zeolite samples indicates that zeolites are effective adsorbents for removing Cr from aqueous solutions. Additionally, the batch experiment revealed that the adsorption pattern conformed to the Langmuir and the Freundlich isotherm models, with correlation factors (R2) of 0.997 and 0.963, respectively.

KEY WORDS: Zeolite, Heavy metal, Chromium, Adsorption, Solution

Bull. Chem. Soc. Ethiop. 2026, 40(10), 2157-2171.                                         

DOI: https://dx.doi.org/10.4314/bcse.v40i10.8