KINETICS AND EQUILIBRIUM STUDIES OF COLOUR PIGMENTS REMOVAL FROM CRUDE PALM OIL USING ACID ACTIVATED KAOLIN CLAY

ABSTRACT

The  adsorptive  removal  of  the  colour  pigment  (due  to  high  content  of  carotenoids)  from  palm oil  using  ortho-phosphoric  acid  activated  kaolin  clay  was  investigated  in  this  research.  The clay  was  activated  at  different  acid  concentrations  to improve  its  adsorptive  capacity.  In  order to  study  the  effect  of  process  variables  on  the  bleaching  efficiency  of  the  raw  and  activated clay  samples,  adsorbent  dosages  (1.0  –  3.0  g);  reaction  temperatures  (30  -  120°C);  and reaction  time  (5  -  60  minutes.)  was  varied  for  the  adsorption  experiment.  The  results  show that  bleaching  efficiency  increases  with  acid  concentrations,  contact  time,  temperature  and clay  dosage. Freundlich  and Langmuir  adsorption  isotherms  were  used  to analyze  the  experimental  results. The  data  conformed  to  Freundlich  Isotherm  model  with  a regression  coefficient  of  0.9673.The experimental  data  were  also  analyzed  using  the  established  kinetic  models  of  Pseudo-first order,  Pseudo-second  order,  and  intra-particle  diffusion.  The  experimental  data  fitted  well  to the  Pseudo-second  order  kinetic  model  with  regression  coefficient  of  0.9982.  The  value  of  ∆H obtained  was  -11.108kJ/mol  which  suggests  that  the  adsorption  process  is  exothermic  and physisorption  in  nature  since  the  magnitude  is  less  than  20kJ/mol.  

TABLE OF CONTENTS

LETTER OF TRANSMITTAL ................................................................................................ ii

CERTIFICATION ................................................................................................................... iii

DEDICATION ........................................................................................................................ iv

ACKNOWLEDGMENT .......................................................................................................... v

ABSTRACT ............................................................................................................................ vi

TABLE OF CONTENTS ....................................................................................................... vii

LIST OF FIGURES .................................................................................................................. x

LIST OF TABLES .................................................................................................................. xi

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

INTRODUCTION ....................................................................................................................1

1.1 Background Study .....................................................................................................1

1.2 Research Aim and Objective .....................................................................................4

1.3 Justification of the Research ......................................................................................4

CHAPTER TWO ......................................................................................................................6

LITERATURE REVIEW .........................................................................................................6

2.1 Palm Oil (Elaeis guineensis)......................................................................................6

2.1.1 Chemical composition of palm oil .....................................................................9

2.1.2 Applications and advantages of palm oil..........................................................14 

2.2 Refining of Palm Oil................................................................................................14

2.2.1 Chemical (Alkaline) Refining ..........................................................................15

2.2.3 Physical Refining..............................................................................................16

2.3 Bleaching by adsorption ..........................................................................................18

2.3.1 Adsorption ........................................................................................................18

2.3.2 Adsorption Isotherms .......................................................................................22

2.3.3 Adsorption Thermodynamics ...........................................................................26

2.3.4 Adsorption kinetics...........................................................................................28

CHAPTER THREE ................................................................................................................30

PROJECT METHODOLOGY ...............................................................................................30

3.1 Materials ..................................................................................................................30

3.2 Clay preparation and activation ...............................................................................30

3.3 Physical characterization of the kaolin clay ............................................................31

3.3.1 Bulk density ......................................................................................................31

3.3.2 Clay moisture content. ......................................................................................31

3.3.3 pH measurement ...............................................................................................32

3.3.4 Porosity .............................................................................................................32

3.3.5 Specific Gravity ................................................................................................32

3.4 Degumming .............................................................................................................32

3.5 Neutralization ..........................................................................................................33 

3.6 Adsorption Experiment............................................................................................33

CHAPTER FOUR ..................................................................................................................35

RESULTS AND DISCUSSION.............................................................................................35

4.1 Physical Characterization of the clay ......................................................................35

4.2 Effect of Acid Concentration on Bleaching Efficiency ...........................................35

4.3 Effect of Contact Time on Bleaching Efficiency ....................................................38

4.4 Effect of Clay Dosage on Bleaching Efficiency ......................................................38

4.5. Effect of Temperature on the Bleaching Efficiency ................................................44

4.6 Effect of the use of Industrial Adsorbent in place of activated Kaolin Clay ...........44

4.7 Adsorption Isotherms...............................................................................................49

4.8 Adsorption Thermodynamics ..................................................................................53

CHAPTER FIVE ....................................................................................................................64

CONCLUSIONS AND RECOMMENDATION ...................................................................64

5.1 CONCLUSION........................................................................................................64

5.2 RECOMMENDATIONS.........................................................................................65

REFERENCES .......................................................................................................................66