SALTSUUD Sitegule， ZULCHIN Hairihan， MUSCHIN Tegshi
College of Chemistry and Environmental Science，Inner Mongolia Key Laboratory of Green Catalysis，
Inner Mongolia Normal University， Hohhot 010022， China
Abstract
Objective Kaolin， characterized by its unique layered structure and strong ion exchange capacity， has been widely used in environmental pollution prevention and wastewater treatment. However， coal-serieskaolin，often discarded as solid waste during coal processing， remains severely underutilized. To enhance its tilization rate， modification treatments are necessary.
Methods In this study， coal-series kaolin from Inner Mongolia was ball-milled and impregnated with alkali， followed by modification in a polyhydroxy-aluminum solution，which was prepared using different ratios of Al3+and OH-. The adsorption capacity of modified kaolin for fluoride （F-）was evaluated. Additionally， influencing factors， including adsorption time， initial solution pH， initial concentration of F-， and the adsorption isotherms and kinetics， were examined to analyze the effects of adsorption conditions on its adsorption performance.
Results and Discussion The kaolin samples after polyhydroxy-aluminum modification were characterized byX-ray diffraction（XRD）， N2 adsorption-desorption， transmission electron microscopy（TEM）， and energy dispersive spectroscopy （EDS）. The results showed that the specific surface area of modified kaolin increased significantly while its structure remained largely unchanged. The removal rate for F- reached 95% at a F- concentration of 10 mg/L， 20 times higher than that of raw kaolin（5%）， demonstrating enhanced F- adsorption performance. Adsorption condition analysis revealed that the optimal F- adsorption performance occurred at a solution pH of 7.0 to 8.0， a thermodynamic temperature of 298 K， a shaking time of 100 min，and a shaking frequency of 200 r/min. The adsorption mechanism was also explored through the evaluation of adsorption kinetics and isotherm models. The adsorption isotherm data conformed to the Freundlich model， while the adsorption kinetics followed the pseudo-second-order model.
Conclusion In this study， a polyhydroxy-aluminum modification method is used to enhance the F- adsorption capacity for coal-serieskaolin.This approach has the advantage of simple preparation process， low cost， low energy consumption， and environmental friendliness. It can effectively improve the adsorption performance of coal-series kaolin for F- ion from water.This approach enhances the effective utilization of coal-series kaolin waste resources and provides a cost-effective adsorbent for treating F--containing water， thereby achieving waste treatment through waste utilization.Future research can explore the recycling potential of polyhydroxy-aluminum-modified kaolin adsorbents to reduce water treatment costs.
Keywords： coal-series kaolin； polyhydroxy-aluminum modification； fluoride removal； adsorption performance
Received: 2024-12-04 .Revised: 2025-03-22 ,Online: 2025-06-03
Funding Project:国家自然科学基金项目， 编号： 22061034。
First Author:撒勒只兀特斯特古乐（2001—），女（蒙古族），硕士生，研究方向为黏土资源综合利用、 水污染物吸附以及多相催化有机合成。E-mail：s20234014021@163.com。
Corresponding Author:穆斯琴特格希（1980—），男（蒙古族），副研究员，博士，硕士生导师，研究方向为黏土资源综合利用、 水污染物吸附以及多相催化有机合成。E-mail：tegshi@imnu.edu.cn。
DOI：10.13732/j.issn.1008-5548.2025.04.014
CLC No:TQ623.6；O647.3；TB4 Type Code: A
Serial No:1008-5548（2025）04-0001-14
