PHOTOCATALYTIC DEGRADATION OF PHARMACEUTICAL WASTE WATER USING TITANIUM DIOXIDE AS PHOTOCATALYST

ABSTRACT

The potential advantage and application of the photocatalytic process using titanium dioxide as the photocatalyst to treat industrial waste water in UV irradiation has been reported. The aim of this work is to investigate the effectiveness of photocatalytic degradation using TiO2 in treating pharmaceutical waste water.

Wastewater was collected from the homogenous tank of effluent treatment plant (ETP) of a Pharmaceutical company. The raw sample was tested and the COD, BOD and pH were found to be 120mg/L, 82.4mg/L and 6.09 respectively. The photocatalyst was then added to the waste water and the mixture was placed in the photocatalytic reactor with UV irradiation. The initial waste water concentration, catalyst dosage, agitation speed, circulation flow rate, UV light intensity and the irradiation time were all varied to observe their effect on the rate of degradation. Thereafter samples from the photocatalytic reactor for each batch experimental study were analysed to know final COD.

The result indicated that a percentage degradation of  100% was achieved when the waste water concentration was 50ml/l, catalyst dosage of 0.75g/l, agitation speed of 900rpm, circulation flow rate 120litres/min, UV intensity of 1000watts and irradiation time of 120minutes being the values of optimum process variables respectively. Graphical plots of the equilibrium data using MS-Excel revealed that the pseudo-second order kinetics best described the kinetics of the process.

Table of Contents

                                                                                           Page

COVER PAGE……………………………………………………………………………..i

TITLE PAGE……………………………………………………………………………….ii

CERTIFICATION………………………………………………………………………….iii

DEDICATION………………………………………………………………………………iv

ACKNOWLEDGEMENT…………………………………………………………………..v

ABSTRACT…………………………………………………………………………………vi

TABLE OF CONTENTS……………………………………………………………………viii

LIST OF TABLES…………………………………………………………………………..xii

LIST OF FIGURES…………………………………………………………………………xiii

LIST OF SYMBOLS………………………………………………………………………xviii

CHAPTER ONE…………………………………………………………………………...1

1.0 INTRODUCTION……………….…………………………………………………………1

1.1     Background of Study………………………………………………………………1

1.2     Aim and Objectives…….…………………………………………………………..4

1.3     Scope of the Study……..………………………………………………………..….4

1.4     Relevance of the Study……………………………………………………………..4

CHAPTER TWO……………………………………………………………………………6

2.0 LITERATURE REVIEW……………………………...........................................................6

2.1 Problems Associated With Industrial Waste Water……………………………….....6

2.2 Classifications of Waste Water………………………………………………………8

       2.2.1 Domestic waste water……………………………………………………………8

       2.2.2 Surface Runoff…………………………………………………………………...8

       2.2.3 Industrial Waste water…………………………………………………………...9

2.3 Physical Characteristics of Wastewater………………………………………………9

2.3.1 Temperature…………………….………………………………………………..9

2.3.2 Color…………………………………………………………...............................9

2.3.3 Odor…………………………………………………………...............................10

2.3.4 Solids…………………………………………………………..............................11

2.4 Chemical Characteristics of Wastewater………………………………………………13

2.4.1 pH…………………………………………………………....................................13

2.4.2 Dissolved Oxygen …………………………………………………………..........14

2.4.3 Nutrients ………………………………………………………….........................14

2.5 Biological Characteristics of Wastewater………………………………………………15

2.5.1 Bacteria …………………………………………………………...........................15

2.5.2 Viruses …………………………………………………………............................15

2.5.3 Parasites ...………………………………………………………...........................15

2.5.4 Molds …………………………………………………………..............................16

2.5.5 Yeasts ………………………………………………………….............................16

2.6 Pharmaceutical Wastewater …………………………………………………………...16

2.7 Environmental and Public Health Impacts of Pharmaceuticals………………………..18

2.8 Conventional Treatment Technology ………………………………………………….20

2.8.1 Treatment of Industrial Wastewater……………………………………………….21

2.9 Advanced Oxidation Processes ………………………………………………………..24

2.9.1 UV-Based Processes ………………………………………………………….......25

2.9.2 UV/O3 Process …………………………………………………………................25

2.9.3 UV/O3/H2O2 Process …………………………………………………………......26

2.9.4 Fe3+/UV-VIS Process…………………………………………………………......27

2.9.5 UV/TiO2 (Heterogeneous photocatalysis) ………………………………………...27

2.9.6 H2O2-Based Processes …………………………………………………………....28

2.10 Photocatalysis ………………………………………………………….......................31

2.10.1 History of Photocatalysis ………………………………………………………..32

2.10.2 Principle of Photocatalysis ………………………………………………………33

2.10.3 TiO2 as a photocatalyst …………………………………………………………...36

2.11 Photo Catalysis Oxidation of Water Borne Organic Pollutants………………………...37

2.12 Application of Advanced Oxidation Process (AOPs)…………………………………..37

2.13 Light Sources…………………………………………………………...........................38

2.14 Photocatalytic Degradation ………………………………………………………….....39

2.15 Photocatalytic Treatment of Industrial Waste Water…………………………………...41

2.16 Photocatalytic Degradation of Pharmaceutical Effluent ……………………………….46

CHAPTER THREE………………………………………’’……………….............................49

3.0 MATERIALS AND METHODS ……………………………………………………........49

3.1 Materials …………………………………………………………..................................49

3.1.1 Pharmaceutical Waste Water ……………………………………………………….49

3.1.2 Reagents and Chemicals Used ……………………………………………………...49

3.2 Instrument Used …………………………………………………………......................50

3.2.1 Multi Lamp UV Flow Thru Photochemical Reactor ……………………………...50

3.2.2 Magnetic Stirrer …………………………………………………………..............50

3.3 Methods and Analysis …………………………………………………………............51

3.3.1 Collection and Storage of Wastewater Sample ……………………………...……51

3.3.2 pH Estimation ………………………………………………………….................51

3.3.3 Estimation of COD…………………………………………………………..........53

3.3.4 Estimation of BOD ………………………………………………………….........55

3.4 Photocatalytic Treatment and Degradation of Pharmaceutical Effluent ………………56

3.4.1 Investigating the Effect of Concentration of TiO2 on the Photocatalytic Treatment of Pharmaceutical Wastewater    …………………………………………………57

3.4.2 Investigating the Effect of Agitation Speed on the Photocatalytic Treatment  of  Pharmaceutical Wastewater………………………………………………………57

3.4.3 Investigating the Effect of flowrate on the Photocatalytic Treatment of Pharmaceutical Waster …………………………………………………………...58

3.4.4 Investigating the Effect of UV Intensity of the Photocatalytic Treatment of Pharmaceutical Wastewater ……………………………………………………..58

3.4.5 Investigating the Effect of Time on the Photocatalytic Treatment of Pharmaceutical Wastewater ………………………………………………………….....................59

CHAPTER FOUR ….……….………………………………………………………...............60

4.0 RESULTS AND DISCUSSION….…………………………………………………..........60

4.1 Characteristics of Wastewater …………………………………………………………60

4.2 Effect of Initial waste water on the Photocatalytic Treatment of Pharmaeceutical Waste Water…………………………………………………………....................................60

4.3 Effect of Catalyst Dosage on the Photocatalytic Treatment of Pharmaeceutical Waste Water…………………………………………………………....................................60

4.4 Effect of Agitation Speed on the Photocatalytic Treatment of Pharmaceutical Waste Water …………………………………………………………...................................63

4.5 Effect of Flow Rate on the Photocatalytic Treatment of Pharmaceutical Waste Water 65

4.7 Effect of UV Intensity on the Photocatalytic Treatment of Pharmaceutical Waste Water………………………………………………………….....................................67

4.7 Effect of Exposure Time on the Photocatalytic Treatment of Pharmaceutical Waste Water …………………………………………………………....................................69

4.8 Kinetic Models…………………………………………………………........................71

4.8.1 Legergren Pseudo First-Order Kinetic Model …………………………………..71

4.8.2 Pseudo Second Order Model …………………………………………………….73

4.8.3 Intra Particle Diffusion Model …………………………………………………..74

CHAPTER FIVE...……………………………………………………….................................76

5.0 CONCLUSION AND RECOMMENDATIONS…………………………………………76

5.1 Conclusion …………………………………………………………............................76

5.2 Recommendations …………………………………………………………................76

REFERENCES …………………………………………………………....................................77

APPENDIX…………………………….…………………………………………………………...86