Research on the Ion Exchange Properties in Hydrochloric Acid-Modified Zeolite for Water Treatment

Zeolite is a group of a few microporous, crystalline aluminosilicate materials which has attracted much attention due to its remarkable absorption, ion exchange, and catalytic behavior. Their uses in water treatment, particularly for heavy metal and ammonium ion removal, have been greatly augmented through chemical modifications. This study investigates the impact of HCl treatment on the physicochemical and structural properties of natural clinoptilolite zeolite. First, it was refluxed with 0.97 M HCl for acid modification and was extensively purified, characterized using FTIR, XRD, gas sorption, and DTG. Overall, compared with the raw material, the results clearly show that the treatment with HCl can increase the surface area and cation exchange capacity, and improve the pore distribution by removing impurities and reorganization of the aluminosilicate building unit. Gas sorption confirmed a 64.4 % increase in the BET surface area (280.3 m²/g), along with a decrease in pore diameter, indicating enhanced adsorption efficiency. Adsorption experiments also indicated that most of the HCl-treated zeolites outperformed the unmodified samples for Disperse Blue 26 (DB 26). Furthermore, although acid modification often improves adsorption characteristics, the research indicates the possibility of structural stability issues stemming from framework leaching. The results of this study revealed the potential of HCl-modified zeolites as efficient and environmentally friendly adsorption materials for water treatment, including wastewater.