Related Experiment Video
Updated: Jun 10, 2026

Resource Recycling of Red Soil to Synthesize Fe2O3/FAU-type Zeolite Composite Material for Heavy Metal Removal
Published on: June 2, 2022
Ammonium removal from aqueous solution by zeolite X synthesized from halloysite mineral
Yafei Zhao1, Bing Zhang, Xiang Zhang
1School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China. zhaoyafei007@126.com
Abstract:
Zeolite X was successfully synthesized from natural halloysite mineral by hydrothermal method. The synthesized zeolite X was characterized by XRD, SEM, TEM and HRTEM. The characterization indicated that zeolite X had high crystallinity together with symmetrical and uniform pore channels. Ammonium (NH₄+) adsorption properties of zeolite X were studied using batch experiments. The results revealed that high initial concentration and low temperature favored NH₄+ adsorption on zeolite X. Both Langmuir and Freundlich isotherms fit well with the equilibrium data. Kinetic studies showed that the adsorption followed pseudo-second-order model. Intra-particle diffusion analysis demonstrated that NH₄+ diffused quickly among the particles at the initial 20 min of the adsorption process, and then the diffusion slowed down and stabilized. Thermodynamic parameters such as change in free energy (ΔG⁰), enthalpy (ΔH⁰) and entropy (ΔS⁰) indicated that the adsorption was spontaneous and exothermic at ambient conditions. The reusable ability of zeolite X was also evaluated. Due to its low cost, high adsorption capacity and fast adsorption rate, zeolite X synthesized from halloysite could be used as an effective and environmental-friendly adsorbent for NH₄+ removal.
Related Concept Videos
Preparation of Amines: Alkylation of Ammonia and Amines
Each alkylation step makes the nitrogen center more nucleophilic, which triggers successive alkylations until a quaternary ammonium salt is formed. Considering...
Qualitative Analysis
For instance, group IV...
Acid Halides to Amides: Aminolysis
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
Basicity of Heterocyclic Aromatic Amines
Diazonium Group Substitution: –OH and –H
Amines to Alkenes: Hofmann Elimination
Under thermal conditions, the hydroxide can abstract a proton from the β carbon; this generates an alkene with the simultaneous...

