Assessment of synthetic zeolites from kaolin and bentonite clays for wastewater and fuel gases treatment

Abstract

The present study evaluates the synthesis, geochemical and mineralogical characterization, as well as the industrial and environmental applications of zeolites synthesized from kaolin and bentonite resources in selected clay deposits of Northeast Africa, Egypt. Several methods were employed to synthesize zeolites from both kaolin and bentonite samples to obtain high purity zeolitic products at a competitive cost. The characterization of the synthesized zeolites, in terms of mineralogy and geochemistry, was conducted using various techniques, including X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and cation exchange capacity (CEC). Additionally, thermo-analytical methods such as thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used. Based on the characterization of zeolites synthesized from bentonite and kaolin, a comparison was made with ideal zeolites used in various industries to determine their potential applications. The synthesized zeolites were evaluated for their effectiveness as adsorbents for H₂S in wastewater and fuel gas purification. Additionally, they were assessed for their ability to remove ions such as Co²⁺, Sr²⁺, and Cs⁺ from aqueous solutions containing organic and suspended solids. Furthermore, these zeolites were investigated for their potential use as commercial and sustainable catalysts for controlling nitrogen oxide (NOx) emissions from diesel engines in vehicles.