Effect of Acid Treatment on the Structure of Natural Zeolite from the Shankhanai Deposit
2025
Sandugash Tanirbergenova | Dildara Tugelbayeva | Nurzhamal Zhylybayeva | Aizat Aitugan | Kairat Tazhu | Gulya Moldazhanova | Zulkhair Mansurov
Natural clinoptilolite from the Shankhanai deposit (Kazakhstan) was modified via acid and thermal treatments to improve its physicochemical and catalytic properties. The zeolite was activated using 10% nitric acid alone, nitric acid followed by thermal treatment (600 °:C), and a mixed acid solution (10% HNO3 + 5% CH3COOH) followed by mild thermal treatment (280 °:C). Structural, textural, and thermal changes were characterized by XRD, FTIR, BET, TGA, SEM, and EDX. Nitric acid treatment increased the BET surface area from 4.95 to 59.9 m2/g but reduced crystallinity, whereas the dual-acid approach enhanced porosity and acidity while preserving framework integrity. Preliminary catalytic testing in thiophene hydrodesulfurization (HDS) revealed improved conversion (up to 20.7%) in the absence of active metals, confirming the potential of modified clinoptilolite as a catalyst support. The dual-acid method presents a promising, eco-friendly pathway for producing thermally stable and catalytically active zeolitic materials, suitable for selective hydrodesulfurization of thiophene.
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