Fluoride ion adsorption from wastewater using magnesium(II), aluminum(III) and titanium(IV) modified natural zeolite: kinetics, thermodynamics, and mechanistic aspects of adsorption

Journal of Water Reuse and Desalination

Mang, Changye¹  Weng, Xingyuan¹  Guan, Zhihao¹  Cheng, Liang¹  Ma, Zhijun¹  Zhang, Qi²  Si, Liwei² 

[1] College of Mining, Liaoning Technical University, Fuxin 123000, China;Research Center of Coal Resources Safe Mining and Clean Utilization, LNTU, Fuxin City, China

关键词: adsorption;    fluoride;    kinetics;    modified natural zeolite;    thermodynamics;   

DOI  :  10.2166/wrd.2017.037

学科分类：工程和技术（综合）

来源: IWA Publishing

【 摘 要 】

Natural zeolite was modified using metal ions, including magnesium(II), aluminum(III) and titanium(IV). The modified zeolite was then used as an adsorbent for the investigation of the adsorption kinetics, isotherms, and thermodynamic parameters of fluoride ions in wastewater at various pHs and temperatures. The kinetics and thermodynamics for the removal of the fluoride ions onto the modified zeolite have also been investigated. The fluoride ion adsorption capacity of the three types of modified zeolites exhibited an increase, then decrease, with rising pH. The fluoride adsorption capacity of the modified zeolites decreased with an increase in temperature. The pseudo-second-order model is more suitable for describing the adsorption kinetic data than the pseudo-first-order model for modified zeolite and the adsorption process of the fluoride ions reveals pseudo-second-order kinetic behavior, respectively. It was found that the adsorption equilibrium data fit the Freundlich isothermal equation better than that of the Langmuir isothermal and Dubinin–Radushkevich (D–R) isothermal equations. Thermodynamic analysis suggests that the negative values of ΔG0 and ΔH0 further indicate that the fluoride adsorption process is both spontaneous and exothermic. The results of competitive adsorption tests suggest that the modified metal zeolite materials adsorb fluoride ions with high selectivity.

【 授权许可】

CC BY-NC-ND