Fabrication of mesoporous beta zeolites for lead ion adsorption from aqueous solutions

Mesoporous beta zeolites were fabricated by treating the parent beta zeolite (B) with two base-acid (BAB) and acid-base (ABB) treatment methods. These zeolites were characterized by X-ray diffraction, N2-adsorption, and lead ion adsorption performance in aqueous solution. BAB and ABB retain the main beta phase characteristics and display mesoporous characteristics, while ABB exhibits a drastic decrease in crystallinity and a substantial increase in nitrogen adsorption compared with BAB. The ABB adsorption ratio and quantity for lead ion reach 90.3% and 23.95 mg/g, which are higher than those of B and BAB under better conditions. Additionally, the results for ABB effectively fit the pseudo-second-order adsorption equation and the Freundlich adsorption model that predicts their lead ion adsorption being multilayer coverage one. Therefore, as a novel mesoporous zeolite, ABB is an excellent lead ion adsorbent and has the potential to remove other metal ions and even organic adsorbates. Also, method 2 (acid-base treatment) is a more effective approach for the synthesis of mesoporous zeolites and even other advanced materials.