Synthesis of Faujasite from Egyptian Clays: Characterizations and Removal of Heavy Metals

Mohamed A Moneim,Ezzat A Ahmed

doi:10.4236/gm.2015.52007

Abstract

Three clay samples with different mineral compositions (kaolinite, smectite-kaoline, and smectite-rich) were used for zeolite synthesis using the method of hydrothermal reactions after fusion with NaOH. The conditions of hydrothermal crystallization (zeolitization) were found to be at temperature of 100°C, and time span between 72 h and 96 h for kaoline and smectite-rich samples, while 48 h for the smectite-kaolinite sample. The results indicate that zeolites began to crystallize from clay samples after 48 h, and crystallization increased with increasing time. The synthetic materials have been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR) and thermogravimetric (DTA/TGA) analysis. The results indicate that low silica NaX-faujasite type with well-developed octahedral and cubic crystals was synthesized from the three samples. No big difference in the characterization between the three synthetic materials was detected, but smectite-kaolinite sample as raw material was relatively better in crystallization of synthetic zeolite. Applications of the synthetic materials in the removal of heavy metals proved that the synthetic faujasite has strong effect for removing of Cr3+, Co2+, Ni2+ and Mn2+ from aqueous solution.

Highlights

Zeolites are crystalline microporous aluminosilicate consisting of tetrahedral units producing open framework structure, which generates a system of pores and cavities having molecular dimensions [1]
Zeolite was synthesized from Egyptian clays with different mineral compositions as raw material
The structure of synthetic product was studied by methods of X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric (DTA/TGA) analysis

Summary

Introduction

Zeolites are crystalline microporous aluminosilicate consisting of tetrahedral units producing open framework structure, which generates a system of pores and cavities having molecular dimensions [1]. A. Ahmed thigh, exchange capacity and sieve properties have been used by many workers in water purifications from heavy metals, ammonia and water softening. Many authors used natural clays as start materials for zeolite synthesis. Kaolinite is the basic raw material used to obtain zeolite with faujasitic structure and with low content of SiO2 such as NaX, NaY and LTA [6] [19]. The objective of this work is to prove which type of natural clay of the studied samples is better in zeolite synthesis using the method of [6], as well as evaluation of the products as waste water purification for heavy metals

Objectives

Methods

Findings

Conclusion