Synthesis and Characterization of Zeolite and Its Application in Adsorption of Nickel from Aqueous Solution

Synthesis and Characterization of Zeolite and Its Application in Adsorption of Nickel from Aqueous Solution.

ABSTRACT  

The synthesis and characterization of zeolite and its application in adsorption of nickel from aqueous solution was investigated. Synthesis of zeolite was performed at 90 o C for 8 h. The size of the resulting crystals increased with an increase in the water content of the reaction mixture. The synthesized zeolite was characterized by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) techniques.

Crystal structure of the product was determined as zeolite X by XRD. The concentration of the nickel ion was determined using atomic absorption spectrophotometer (AA 320 – ON). Removal efficiency of nickel ion was dependent on the pH, contact time, adsorbent dosage and temperature. Batch adsorption studies conducted for the removal of nickel (II) ion at 25, 40 and 50 o C respectively showed that nickel ion adsorption increased with increase in temperature.

The effect of adsorbent dosage of 0.5-4.5 g showed that there was an increase in the adsorption capacity when the adsorbent dose was increased from 2.0-4.0 g. The pH values were adjusted to 3.2, 4.3, 5.3, 6.7, 7.9 and 9.5 and it was evident from the result that at pH 5.3, uptake capacity of nickel (II) ion onto zeolite X was maximum. The effect of contact time at 10, 20, 30, 45, 60, 75 and 90 min was analysed and it was evident that adsorption of nickel was rapid in the first 40 min followed by a gradual increase until equilibrium was attained.

TABLE OF CONTENTS

Title page .. .. .. .. .. .. .. .. .. i
Approval page .. .. .. .. .. .. .. .. .. ii
Certification page .. .. .. .. .. .. .. .. .. iii
Dedication .. .. .. .. .. .. .. .. .. iv
Acknowledgment .. .. .. .. .. .. .. .. .. v
Abstract vi
Table of contents .. .. .. .. .. .. .. .. .. vii
List of table .. .. .. .. .. .. .. .. .. .. x
List of figure .. .. .. .. .. .. .. .. .. xii
List of abbreviations .. .. .. .. .. .. .. .. .. xiv

CHAPTER ONE
1.0 Introduction .. .. .. .. .. .. .. .. .. .. 1
1.1 Background of study .. .. .. .. .. .. .. .. 2
1.2 Statement of problem .. .. .. .. .. .. .. .. 3
1.3 Objectives of the study .. .. .. .. .. .. .. .. .. 3
1.4 Justification .. .. .. .. .. .. .. .. .. .. 3

CHAPTER TWO
2.0 Literature review .. .. .. .. .. .. .. .. .. 4
2.1 Natural zeolites .. .. .. .. .. .. .. .. .. 6
2.2 Synthetic zeolite .. .. .. .. .. .. .. .. .. 9
2.2.1 Synthetic zeolite from natural materials .. .. .. .. .. .. 13
2.2.2 Synthetic zeolite from waste materials .. .. .. .. .. .. 15
2.2.2.1 Zeolites from coal fly ash (CFA) .. .. .. .. .. .. 15
2.2.2.2 Zeolite from municipal solid waste incineration ash (MSWIA) .. .. .. 16
2.2.2.3 Zeolites from oil shale ash (OSA) .. .. .. .. .. .. .. 17
2.2.2.4 Zeolite from rice husk ash (RHA) .. .. .. .. .. .. 17
2.2.2.5 Zeolite from other wastes .. .. .. .. .. .. .. 18
2.2.2.6 Modified natural and synthetic zeolites .. .. .. .. .. .. 19
2.3 Application of zeolite: (waste) water treatment .. .. .. .. .. 20
2.3.1 Heavy metals removal .. .. .. .. .. .. .. .. 20
2.3.1.1. Industrial wastewater sources .. .. .. .. .. .. .. 25
2.3.1.2 Adsorption of heavy metals on adsorbent .. .. .. .. .. 26
2.3.1.3 Mechanisms of heavy metals removal from industrial wastewater .. .. 27
2.3.2 Water softening .. .. .. .. .. .. .. .. .. 28
2.3.3 Ammonia removal .. .. .. .. .. .. .. .. .. 30
2.3.4 Radioactive species removal .. .. .. .. .. .. .. 34
2.3.5 Removal of inorganic anions .. .. .. .. .. .. .. 36
2.3.6. Organic compounds removal .. .. .. .. .. .. .. 37
2.3.6.1 Dyes removal .. .. .. .. .. .. .. .. .. 39
2.3.6.2 Micro organism capturing .. .. .. .. .. .. .. 38
2.3.6.3 Removal of others organics .. .. .. .. .. .. .. 41
2.4 Permeable reactive barriers (PRB) .. .. .. .. .. .. .. 41
2.5 Sea Water desalination .. .. .. .. .. .. .. .. 42
2.6 Adsorption isotherms .. .. .. .. .. .. .. .. 44

CHAPTER THREE
3.0 Experimental .. .. .. .. .. .. .. .. .. .. 46
3.1 General .. .. .. .. .. .. .. .. .. .. 46
3.1.1Synthesis of zeolite .. .. .. .. .. .. .. .. .. 47
3.1.2 Effect of pH .. .. .. .. .. .. .. .. .. 49
3.1.3 Effect of temperature .. .. .. .. .. .. .. .. 49
3.1.4 Effect of adsorbent concentration .. .. .. .. .. .. 50
3.1.5 Effect of contact time .. .. .. .. .. .. .. .. 50

CHAPTER FOUR
4.0 Results and discussion .. .. .. .. .. .. .. .. 51
4.1 Scanning electron microscopy … …. … .. … .. .. … .. .. .. 51
4.2 X-ray diffraction .. …. .. .. .. .. .. .. .. .. .. .. 53
4.3 Effect of pH .. .. .. .. .. .. .. .. .. 55
4.4 Effect of temperature .. .. .. .. .. .. .. .. .. 56
4.5 Effect of amount of adsorbent .. .. .. .. .. .. .. 57
4.6 Effect of contact time .. .. .. .. .. .. .. .. 60
4.7 Adsorption isotherms .. .. .. .. .. .. .. .. .. 61
4.8 Adsorption kinetics .. .. .. .. .. .. .. .. .. .. .. 62

CHAPTER FIVE
Conclusion .. .. .. .. .. .. .. .. .. .. 68
References .. .. .. .. .. .. .. .. .. .. 69
Appendix .. .. .. .. .. .. .. .. .. .. 80

INTRODUCTION  

Zeolites are porous crystalline alumino-silicates of regular skeleton structures formed by alternating silicon-oxygen and aluminum-oxygen tetrahedrons. Although only natural zeolites were initially used, synthetic zeolites, due to their well-tailored and highlyreproducible structures, have been used extensively as ion exchangers, adsorbents, separation materials and catalyst.

The negative charges in aluminum-oxygen tetrahedron, which are not rigidly fixed to the skeleton of zeolites, are compensated with cations, so they are capable of interchanging. Silicon-oxygen and aluminum-oxygen tetrahedrons in the zeolites of the type A, X and Y form a complex structural unit of cubooctahedron. The combination of such units forms the structure of type A, X and Y [fig 7].

The difference between them consists in the fact that they are interconnected by means of different number of member rings (i.e., eight member rings (A), twelve member rings (X, Y). The chemical difference of zeolite is defined by the ratio of Si/Al. For zeolite A this value is in the range of 0.95-1.051-3. Zeolites A, X and Y are the most important ones to be used in pharmaceutical, petrochemical and detergent industries.

Zeolites with different structure are known to be obtained by synthesis 2-7. They are either synthesized from alumino-silicate hydrogel or by conversion of clay minerals. The hydrogel can be prepared from different sources of silica and alumina, but the types of starting materials and the method of mixing determine the structure of the resulting gel. 

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CSN Team.

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