Synthesis of zeolite 4A via acid–base activation of metakaolinite and its use for water hardness treatment

Abstract

The synthesis of zeolite 4A from raw kaolinite has been studied using acid–base activation method. The raw kaolinite was first converted to metakaolinite and then dealuminated via acid treatment. Dissolution of the silicate in the unreacted solid was affected with base. The acid solution was blended with aluminum and then mixed with the silicate solution to form gel that allowed to crystallize in hot water bath. The crystallized zeolite 4A formed was separated, washed thoroughly with distilled water, characterized via XRF, XRD, scanning electron microscopy, and tested for water softening.