ii

ACTIVATED CARBON FROM EMPTY FRUIT BUNCH OF OIL PALM

AND ITS POTENTIAL IN BISPHENOL-A REMOVAL

MOHD AIDIL BIN ELIAS

UNIVERSITI TEKNOLOGI MALAYSIA

ii

ACTIVATED CARBON FROM EMPTY FRUIT BUNCH OF OIL PALM

AND ITS POTENTIAL IN BISPHENOL-A REMOVAL

MOHD AIDIL BIN ELIAS

A thesis submitted in fulfillment of the

requirements for the award of the degree of

Master of Engineering (Environment)

Faculty of Civil Engineering

Universiti Teknologi Malaysia

JUNE 2016

iii

To my dearest:

Parents,

Siblings,

Family,

Supervisors

and

Friends

DEDICATION

iv

First and foremost to my kind supervisors, Prof. Dr. Mohd Razman Salim,

Prof. Dr. Abdull Rahim Yusoff and Dr. Tony Hadibarata from UTM who have given

lots of ideas, guidance and critics which has strengthened up my research.

My deepest appreciation to my beloved parents Elias bin Ahmad and

Normadiah binti Musa for giving a valuable support and encouragement while

conducting this research. To my dearest sibling, Zulkarnain, Izwan, Luqman and

Nurelissa for their support that made me stronger to finish this research.

To all my friends, Amir, Shafik, Hanis, Izzul, Basri, Zuna, Azam, Ubai, Epul,

Nabil, Akmal, Amin, Zainab, Mimi, Shahrul, Azizul, Amirul, Faizul, Mior and to all

my lab mates who had been very kind to me throughout this research. All your help

had helped me a lot to make this thesis possible. Last but not least, million thanks to

each and every individual who had lent helpful hands throughout this entire research

in a way or another. The experiences that I gained here will be remembered for the

rest of my life. Thank you very much.

ACKNOWLEDGEMENT

v

. Powdered activated carbon (PAC) based adsorption method is one of the

promising techniques in the field of wastewater treatment due to its high efficiency,

and less time consumption. Unfortunately, its application in water treatment is rather

restricted due to high cost. This study used an abundant and locally available waste

product generated from palm oil mill called Empty Fruit Bunch (EFB) as an

alternative substituent to produce activated carbon (AC). Alternative use of this

waste not only gives economic solution but also reduces environment problems

caused by the waste after being disposed of into landfills and left unused. The

experimental design for production of EFB-AC was prepared using Design-Expert

Software. The EFB-AC was produced inside a tube furnace where the effects of

activation temperature, activation time, nitrogen gas flow were investigated. EFB-

AC was chemically activated using Potassium Hydroxide (KOH) as activating agent

under impregnation ratio of 3:1. The effectiveness of the EFB-AC produced in the

removal of Bisphenol A (BPA) was determined. BPA is considered as a typical

endocrine disrupting chemical which may influence human living systems. Effects of

pH, AC-Dosage and contact time on the removal of BPA were investigated. The

optimum conditions for preparing the activated carbon were found at temperature of

850�C with activation time of 30 minutes and nitrogen flow gas at 90 mm/min. The

results show that at contact time of 48 hours, AC-dosage 1.0 g and at pH 9.0, for

EFB-AC gave optimum removal of BPA at 84.9%. For comparative study between

EFB-AC and commercial AC, the removal of BPA was found at 84.9% and 96.2%

respectively at 48 hours contact time, 1.0 g AC-dosage and at pH 9.0. The EFB-AC

was analysed using SEM, EDX and FTIR to study the characterization and

microstructure of the AC produced.

ABSTRACT

vi

Kaedah penjerapan berasaskan serbuk karbon teraktif (PAC) merupakan

salah satu teknik yang biasa digunakan dalam bidang olahan air sisa kerana ia

mempunyai kecekapan tinggi dan mengunakan masa yang singkat. Malangnya,

penggunaannya dalam bidang olahan air adalah terhad kerana kos yang tinggi.

Kajian ini menggunakan bahan buangan yang banyak dan senang diperolehi yang

dihasilkan daripada kilang minyak sawit iaitu tandan buah kosong (EFB) sebagai

sumber alternatif untuk menghasilkan karbon teraktif (AC). Penggunaan sisa ini

bukan sahaja merupakan penyelesaian yang menjimatkan, ia juga boleh

mengurangkan masalah alam sekitar yang disebabkan oleh bahan sisa yang dibuang

ke pusat kambus tanah dan tidak digunakan. Penghasilan karbon teraktif adalah

berdasarkan reka bentuk eksperimen yang dibantu dengan menggunakan perisian

Design Expert. Karbon teraktif telah dihasilkan dalam tiub relau yang mana kesan

seperti suhu pengaktifan, masa pengaktifan, aliran gas nitrogen telah dikaji. EFB-AC

telah diaktifkan secara kimia dengan menggunakan kalium hidroksida sebagai ejen

pengaktifan di bawah pengisitepuan pada nisbah 3:1. Keberkesanan EFB-AC yang

dihasilkan dalam penyingkiran Bisphenol A (BPA) telah dikaji. BPA merupakan

bahan kimia pemusnah endokrin yang boleh mempengaruhi sistem hidup manusia.

Kesan pH, Dos-AC dan masa sentuhan, terhadap penyerapan BPA telah ditentukan.

Keadaan optimum untuk penyediaan karbon teraktif diperolehi pada suhu 850�C,

masa pengaktifan 30 min dan aliran gas nitrogen pada 90 mm / min. Keputusan bagi

masa hubungan 48 jam, Dos-AC 1.0 g dan pH 9.0 untuk EFB-AC memberikan

penyingkiran optimum BPA sebanyak 84.9%. Bagi kajian perbandingan antara EFB-

AC dan AC komersial menunjukkan penyingkiran BPA pada 84.9% dan 96.2%

masing-masing pada masa hubungan 48 jam, Dos-AC 1.0 g dan pH 9.0. EFB-AC

telah dianalisis menggunakan SEM, EDX dan FTIR bagi mengkaji perincian dan

strukturmikro EFB-AC yang dihasilkan.

ABSTRAK

vii

TABLE OF CONTENTS

CHAPTER

TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES xi

LIST OF FIGURES xii

LIST OF ABBREVATIONS xiv

LIST OF APPENDICES xv

1 INTRODUCTION 1

1.1 Background of the Study 1

1.2 Problem Statement 3

1.3 Objectives 3

1.4 Scope of Study 4

1.5 Significances and Original Contributions of This Study 5

2 LITERATURE REVIEW 6

2.1 Introduction 6

viii

2.2 Bisphenol A 7

2.2.1 Effects of Bisphenol A in Human Health 9

2.3 Oil Palm 10

2.3.1 Empty Fruit Bunches 12

2.4 Activated carbon 13

2.4.1 Materials for Activated Carbon and their structure 16

2.4.2 Activated Carbon Production 17

2.5 Adsorption 20

2.6 Adsorption Isotherms 21

2.6.1 Langmuir Isotherm 22

2.6.2 Freundlich Isotherm 22

2.6.3 Temkin Isotherm 23

2.7 Adsorption Kinetics 24

2.8 Factors Affecting AC Adsorption 24

2.8.1 Raw material 25

2.8.2 Temperature 26

2.8.3 Activation time 27

2.8.4 Carbonization 28

2.9 Batch Adsorption 28

3 METHODOLOGY 29

3.1 Introduction 29

3.2 Chemicals and Materials 31

3.3 Experimental Design 32

3.3.1 Sample Collection and Preparation 33

3.4 Activated Carbon Production 33

3.5 Adsorption Test (Batch Adsorption Test) 35

ix

3.6 Characterization of the EFB-AC produced 36

3.6.1 Scanning Electron Microscope Image (SEM) 37

3.6.2 Energy-dispersive X-ray spectroscopy (EDX) 37

3.6.3 Attenuated Total Reflection by Fourier Transform Infrared

Spectroscopy (ATR-FTIR) 37

3.6.4 Moisture Content 38

3.6.5 Ash Content 38

3.7 Optimization Study 39

3.8 Adsorption Isotherms (Freundlich and Langmuir) and Adsorption

Kinetics Study 39

3.8.1 Adsorption Isotherm and Kinetic Study Test 40

4 RESULTS AND DISCUSSIONS 43

4.1 Introduction 43

4.2 Production and Optimization of Activated Carbon 44

4.2.1 Carbonization Process 44

4.3 Sample Characterization 48

4.3.1 Activated carbon surface Morphology 49

4.3.2 Attenuated Total Reflection by Fourier Transform Infrared

Spectroscopy (ATR-FTIR) 53

4.3.3 Energy-dispersive X-ray spectroscopy (EDX) 57

4.4 Optimum conditions studies for removal of Bisphenol A 59

4.4.1 Studies the effects of Contact time, AC Dosage, BPA

concentration and pH on BPA removal. 62

4.4.2 Effects of Contact Time on BPA adsorption 63

4.4.3 Effects of AC Dosage on BPA Adsorption. 64

4.4.4 Effects of BPA Concentration on BPA Adsorption. 66

4.4.5 Effects of pH on BPA Adsorption 67

x

4.5 Comparative Study with Commercial Activated Carbon 68

4.6 Adsorption Kinetics 69

4.7 Adsorption Isotherms 72

5 CONCLUSION 76

5.1 Overview 76

5.2 Conclusion of Research Finding based on Objectives 76

5.2.1 Objectives 1: To identify the psycho-chemical

characterization of EFB-AC produced. 77

5.2.2 Objectives 2: To determine the optimum conditions for

Bisphenol A removal by EFB based AC. 77

5.2.3 Objectives 3: To study the adsorption isotherms and

adsorption studies of Bisphenol A removal by EFB based

AC. 78

5.3 Recommendations for Future Work 79

REFERENCES 80

APPENDICES 85

xi

LIST OF TABLES

TABLE NO. TITLE PAGE

2.1 Physical and Chemical properties of Bisphenol - A

8

2.2 Summary of Researchers on capability of Oil Palm-EFB as

Activated Carbon

17

3.1 Chemical used in experiment

31

3.2 Equipment used in the experiments

32

3.3 AC production runs

33

3.4 EFB-AC sample adsorption runs

35

4.1 Preparation of char experimental design and experiment

response

43

4.2 ANOVA for selected factorial model for adsorption

capacity

44

4.3 ANOVA for selected factorial model for adsorption

capacity (reduced model)

46

4.4 Characterization of activated carbon produced

47

4.5 IR-Spectra and functional group

52

4.6 EFB-AC sample adsorption runs

59

4.7 Pseudo first order and pseudo second order adsorption rate

constant values for BPA adsorption onto AC produced

71

xii

LIST OF FIGURES

FIGURES NO. TITLE PAGE

2.1 Bisphenol A’s Chemical Structure

8

2.2 Fresh Fruit Bunches of Oil Palm Tree

11

2.3 Oil Palm Plantation

12

2.4 Empty Fruit Bunch

13

2.5 Empty Fruit Bunches as fertilizer

13

2.6 Activated Carbon

15

3.1 Flow Chart of the experiments

30

3.2 Empty fruit bunch fibers

31

4.1 Three dimensional response surface plot for BPA

removal (effect of temperature and time) with nitrogen

gas-flow at 2.50 L/min

46

4.2 SEM micrograph of EFB Fiber (500x)

49

4.3 SEM micrograph of EFB Fiber (1.5x)

50

4.4 SEM micrograph of carbonized EFB (500x)

50

4.5 SEM micrograph of carbonized EFB (1.5x)

51

4.6 SEM micrograph of EFB-AC (500x)

51

4.7 SEM micrograph of EFB-AC (500x)

52

4.8 IR Spectrum of Raw EFB

54

4.9 IR Spectrum of Carbonized EFB

55

xiii

4.10 IR Spectrum of EFB-AC

55

4.11 IR Spectrum of EFB-AC after BPA Adsorption

56

4.12 IR Spectrum of Commercial AC

56

4.13 Element Analysis in EFB Fiber

57

4.14 Element Analysis in EFB Char

57

4.15 Element Analysis in EFB-AC

58

4.16 Element Analysis in Commercialized AC

58

4.17 3D surface plot of removal capacities on pH and dosage

61

4.18 3D surface plot of removal capacities on time and

dosage

61

4.19 Effect of Contact Time on BPA Adsorption

63

4.20 Effect of AC Dosage on BPA Adsorption

64

4.21 Effect of BPA Concentration on BPA Adsorption

66

4.22 Effect of pH on BPA Adsorption

67

4.23 Comparative study between commercial activated

carbon with EFB-AC

68

4.24 Pseudo-first order kinetics for adsorption of BPA onto

AC produced

70

4.25

Pseudo-second order kinetics for adsorption of BPA

onto AC produced

71

4.26 Linearised Langmuir isotherm plots for BPA adsorption

by EFB-AC

73

4.27 Linearised Freundlich isotherm plots for BPA

adsorption by EFB-AC

73

4.28 Linearised Temkin isotherm plots for BPA adsorption

by EFB-AC

74

xiv

LIST OF ABBREVATIONS

EFB - Empty fruit bunches

AC - Activated carbon

EDC - Endocrine disrupting chemical

BPA - Bisphenol A

RSM - Response Surface Methodology

SEM - Scanning Electron Microscope

EDX - Energy-dispersive X-ray spectroscopy

ATR-FTIR - Attenuated Total Reflection-Fourier Transformation

Infrared

EFB-AC - Empty fruit bunch activated carbon

ANOVA - Analysis of variance

xv

LIST OF APPENDICES

APPENDIX TITLE PAGE

A APPENDIX 1 86

B APPENDIX 2 87�

CHAPTER 1

INTRODUCTION

1.1 Background of the Study

Adsorption process by activated carbon (AC) is one of the most effective and

widely used methods to purify water stream. The sludge free operation makes

absorption process better than other treatments available (Alam et al., 2009).

Numerous industries used activated carbon as adsorbents for removal of organic

contaminants from water streams.

Activated carbons are carbonaceous materials that have high adsorption

capability due to its high porosity. Activated Carbon is generally considered to have

beneficial environmental effects, thus its recommendation by USEPA to treat waste

water effluent from the food industry (USEPA, 2000).

However, the usage of activated carbon is limited by their high commercial

costs which lead to high production cost. In recent years, many studies have been

conducted in order to search the substituent that’s abundantly available and less

expensive materials for production of activated carbon. Agricultural wastes are the

potential precursors because of the abundant supply and low cost. Moreover,

transforming agricultural wastes into valuable end products may help to increase

crop yields and production efficiency as well to reduce solid wastes disposal

problem.

2

The production of activated carbon from Empty fruit bunches (EFB) seems

to be a good approach as Malaysia is a giant producer of oil in the world, about two

million tons (dry weight) of shell and one million tons of extracted fiber are

generated annually. Normally, they are used as boiler fuels or building materials.

This waste will pose great danger to environments as most of the Empty Fruit Bunch

residues are left unused and being handled as a solid waste. This biomass creates

problems with waste treatment and disposal, open dumping/landfill, and groundwater

contamination from leachate.

Besides that, burning of biomass causes emission of haze hazard and toxic

chemicals such as dioxins. Thus, it is necessary to make a better use of these cheap

and abundant wastes, it is proposed to make them into effective adsorbents such as

activated carbons (Guo et al., 2005). In 2003, the biomass production of palm kernel

shell was about 8 million tons are produced (www.mpob.gov.my, Malaysian Palm

Oil Board). Accordingly studies of effective utilization and recovery of EFB become

urgent and significant issue. Hence, the aim of this study was to evaluate the

adsorption efficiency of the AC prepared from EFB for removing Bisphenol A.

Bisphenol A (BPA) widely used as a monomer for production of epoxy resins

and polycarbonate in the plastic industry. BPA has been listed as one of endocrine

disrupting chemical (EDC) which can pose a risk to human health and reproductive

biology. The pollution of EDCs in surface water has aroused the public concern and

significant effort need to be done to remove it from the drinking water.

This research’s aim is to further explore the application of EFB as biosorbent

for BPA adsorption. The effects of various experimental parameters on the

adsorption of BPA were also being investigated.

3

1.2 Problem Statement

As one of the largest producer of palm oil in the worlds, Malaysia also

generated huge amount of solid waste namely Empty fruit bunch (EFB) at about 12.4

million tons/year (fresh weight) (Tanaka et al., 2004). This waste will pose great

danger to environments as most of the empty fruit bunch residues are left unused and

being handled as a solid waste. This waste will bring problems if not handled

properly such as open dumpling and groundwater contamination from leachate. This

study seeks to employ the conversion of empty fruit bunch, EFB into AC which has

relevant application in many areas but for the purposes of this study it will be limited

to the removal of Bisphenol A from aqueous solution.

Bisphenol A is widely used as a monomer for production of epoxy resins and

polycarbonate in the plastic industry. It is widely used for manufactured of baby

bottles, lining of food cans and also dental sealants (Bautista-Toledo et al., 2005). As

one of the phenolic endocrine disrupting chemicals (EDCs) Bisphenol A may cause

potential risks to human health. The present of BPA in drinking water became

serious health issues as this compound can affect the body’s developments, growth

and hormone balance by mimicking, blocking or disrupting the body’s natural

hormones. Accordingly, significant effort for developing an effective technology to

remove it from the aqueous phase must be made.

1.3 Objectives

This research aims are:

1. To identify the psycho-chemical characterization of EFB-AC produced.

2. To determine the optimum conditions for Bisphenol A removal by EFB based

AC.

4

3. To determine the adsorption capacity and adsorption rate of Bisphenol A

removal by EFB-AC.

1.4 Scope of Study

This study investigates alternative and cheap source for production of

activated carbon. Empty fruit bunch was waste product generated from the palm oil

mill after extraction of their oil. This waste generated in large volumes constitute an

environmental threats, thus a safe method for their disposal is sort through

conversion to AC.

Response Surface Methodology (RSM) statistical software with Box-Benken

application was applied to get the optimum conditions of experiment parameter (i.e.

carbonization process, nitrogen gas flow and residence time). This raw material will

undergo carbonization process under nitrogen gas flow at different range of

carbonization temperature (i.e. 550 – 850 °C), residence time (i.e. 30 – 60 minutes)

and Nitrogen gas flow (i.e. 2 – 3 L/min). Then, the optimal processing condition for

adsorption of Bisphenol A in aqueous solution will be determined. Potassium

hydroxide was used to activate the carbonized carbon samples under chemical

activation. The AC produced was then characterized by Scanning Electron

Microscope (SEM), Energy-dispersive X-ray spectroscopy (EDX), Attenuated Total

Reflection-Fourier Transformation Infrared (ATR-FTIR).

The prepared sample’s performances was then analyzed by Bisphenol A

adsorption test at different pH, contact time, BPA initial concentration and activate

carbon dosage.

5

1.5 Significances and Original Contributions of This Study

This study is being carried out in order to curtail the likelihood of waste being

generated from palm oil processing from constituting challenges in landfill

management among other agricultural byproducts. The Empty Fruit Bunch-Activated

Carbon (EFB-AC) produced is considered a viable and economical substitute for

commercial activated carbon.

As in 2002, the demand for activated carbon reached 200,000 ton per year in

United States. The demands of AC were increase over the year and market growth

was estimated at 4.6% per year (Bautista-Toledo et al., 2005). The market has been

increasing constantly as a consequence of environmental issues, especially water and

air purification.

Furthermore, as more and more countries are becoming industrialized, the

need for activated carbon to comply with environmental regulation will grow fast.

The growth of the activated carbon market in the last two decades in the most

industrialized region will very probably continue in the near future as more

developing areas of the world will realize the importance of controlling water and air

pollution. The continuous research has to be implementing to develop the high

quality of AC for specific uses.

REFERENCES

Alam, Z., Ameem, E.S., Muyibi, S.A., and Kabbashi, N.A. (2009) The factors affecting the performance of activated carbon prepared from oil palm empty fruit bunches for adsorption of phenol. 155, 191–198.

Asada, T., Oikawa, K., Kawata, K., Ishihara, S., Iyobe, T., and Yamada, A. (2004)

Study of Removal Effect of Bisphenol A and ␤ -Estradiol by Porous Carbon. 50, 588–593.

Baccar, R., Sarrà, M., Bouzid, J., Feki, M., and Blánquez, P. (2012) Removal of pharmaceutical compounds by activated carbon prepared from agricultural by-product. Chemical Engineering Journal, 211-212, 310–317. Elsevier B.V.

Bagheri, N. and Abedi, J. (2009a) Chemical Engineering Research and Design Preparation of high surface area activated carbon from corn by chemical activation using potassium hydroxide. 7, 1059–1064.

Bagheri, N. and Abedi, J. (2009b) Preparation of high surface area activated carbon from corn by chemical activation using potassium hydroxide. Chemical Engineering Research and Design, 87, 1059–1064.

Bautista-Toledo, I., Ferro-García, M. a., Rivera-Utrilla, J., Moreno-Castilla, C., and Fernández, F.J.V. (2005) Bisphenol A removal from water by activated carbon. Effects of carbon characteristics and solution chemistry. Environmental Science and Technology, 39, 6246–6250.

Bhatnagar, A., Hogland, W., Marques, M., and Sillanpää, M. (2013) An overview of the modification methods of activated carbon for its water treatment applications. Chemical Engineering Journal, 219, 499–511.

Bousba, S. and Meniai, A.H. (2013) Adsorption of 2-chlorophenol onto sewage sludge based adsorbent: Equilibrium and kinetic study. Chemical Engineering Transactions, 35, 859–864.

Chiu, Y.T., Lin, C.S., and Chang, C. (2011) In vitro fruiting and seed production in Erycina pusilla (L.) N. H. Wiliams & M. W. Chase. Propagation of Ornamental Plants, 11, 131–136.

Corley, R.H. V. (2009) How much palm oil do we need ? 12, 134–139.

81

Cuerda-Correa, E.M., Díaz-Díez, M. a., Macías-García, a., and Gañán-Gómez, J. (2006) Preparation of activated carbons previously treated with sulfuric acid. Applied Surface Science, 252, 6042–6045.

Dabrowski, a. (2001) Adsorption--from theory to practice. Advances in colloid and interface science, 93, 135–224.

Dastgheib, S. a. and Rockstraw, D. a. (2001) Pecan shell activated carbon: Synthesis, characterization, and application for the removal of copper from aqueous solution. Carbon, 39, 1849–1855.

Demirbas, A. (2004) Effects of temperature and particle size on bio-char yield from pyrolysis of agricultural residues. Journal of Analytical and Applied Pyrolysis, 72, 243–248.

El-Sheikh, A.H., Newman, A.P., Al-Daffaee, H.K., Phull, S., and Cresswell, N. (2004) Characterization of activated carbon prepared from a single cultivar of Jordanian Olive stones by chemical and physicochemical techniques. Journal of Analytical and Applied Pyrolysis, 71, 151–164.

Foo, K.Y. and Hameed, B.H. (2009) Utilization of biodiesel waste as a renewable resource for activated carbon: Application to environmental problems. Renewable and Sustainable Energy Reviews, 13, 2495–2504.

Foo, K.Y. and Hameed, B.H. (2013) Utilization of oil palm biodiesel solid residue as renewable sources for preparation of granular activated carbon by microwave induced KOH activation. Bioresource Technology, 130, 696–702.

Fuadi, N.A.B., Ibrahim, A.S., and Kamriah, I. (2012) Review study for activated carbon from palm shell used for treatment of waste water,. Journal of Purity, Utility Reaction and Environment, 1, 252–266.

Girgis, B.S. and El-Hendawy, (2002) Porosity development in activated carbons obtained from date pits under chemical activation with phosphoric acid. Microporous and Mesoporous Materials, 52, 105–117.

Guo, J., Xu, W.S., Chen, Y.L., and Lua, A.C. (2005) Adsorption of NH 3 onto activated carbon prepared from palm shells impregnated with H 2SO 4. Journal of Colloid and Interface Science, 281, 285–290.

Haimour, N.M. and Emeish, S. (2006) Utilization of date stones for production of activated carbon using phosphoric acid. Waste Management, 26, 651–660.

Hameed, B.H., Tan, I.A.W., and Ahmad, A.L. (2009) Preparation of oil palm empty fruit bunch-based activated carbon for removal of 2 , 4 , 6-trichlorophenol : Optimization using response surface methodology. 164, 1316–1324.

Han, X., Wang, W., and Ma, X. (2011) Adsorption characteristics of methylene blue onto low cost biomass material lotus leaf. Chemical Engineering Journal, 171, 1–8. Elsevier B.V.

82

Hesas, R.H., Arami-Niya, A., Wan Daud, W.M.A., and Sahu, J.N. (2013) Preparation and characterization of activated carbon from apple waste by microwave-assisted phosphoric acid activation: Application in methylene blue adsorption. BioResources, 8, 2950–2966.

Kadirvelu, K., Thamaraiselvi, K., and Namasivayam, C. (2001) Removal of heavy metals from industrial wastewaters by adsorption onto activated carbon prepared from an agricultural solid waste. Bioresource Technology, 76, 63–65.

Kadirvelu, K., Kavipriya, M., Karthika, C., Radhika, M., Vennilamani, N., and Pattabhi, S. (2003) Utilization of various agricultural wastes for activated carbon preparation and application for the removal of dyes and metal ions from aqueous solutions. Bioresource Technology, 87, 129–132.

Kilic, M., Apaydin-Varol, E., and Pütün, A.E. (2011) Adsorptive removal of phenol from aqueous solutions on activated carbon prepared from tobacco residues: Equilibrium, kinetics and thermodynamics. Journal of Hazardous Materials, 189, 397–403.

Li, Z. and Gondal, M.A. (2014) Preparation of magnetic separable CoFe 2 O 4 / PAC composite and the adsorption of bisphenol A from aqueous solution. Journal of Saudi Chemical Society, 18, 208–213. King Saud University.

Malik, P.K. (2004) Dye removal from wastewater using activated carbon developed from sawdust: Adsorption equilibrium and kinetics. Journal of Hazardous Materials, 113, 81–88.

Mazaheri, H., Lee, K.T., Bhatia, S., and Mohamed, A.R. (2010) Subcritical water liquefaction of oil palm fruit press fiber in the presence of sodium hydroxide: An optimisation study using response surface methodology. Bioresource Technology, 101, 9335–9341. Elsevier Ltd.

Misson, M., Haron, R., Kamaroddin, M.F.A., and Amin, N.A.S. (2009) Pretreatment of empty palm fruit bunch for production of chemicals via catalytic pyrolysis. Bioresource Technology, 100, 2867–2873. Elsevier Ltd.

Molina-Sabio, M., RodRíguez-Reinoso, F., Caturla, F., and Sellés, M.J. (1995) Porosity in granular carbons activated with phosphoric acid. Carbon, 33, 1105–1113.

Moreno-Castilla, C., Carrasco-Marín, F., López-Ramón, M.V., and Alvarez-Merino, M. a. (2001) Chemical and physical activation of olive-mill waste water to produce activated carbons. Carbon, 39, 1415–1420.

Muyibi, S.A., Kamaldin, N., and Gombak, J. (2008) Production Of Activated Carbon From Oil Palm Empty Fruit Bunches For Removal Of Zinc. 1–11.

Nakanishi, A., Tamai, M., Kawasaki, N., Nakamura, T., and Tanada, S. (2002) Adsorption Characteristics of Bisphenol A onto Carbonaceous Materials Produced from Wood Chips as Organic Waste. 396, 393–396.

83

Noor, A. Bin, Asri, M., and Mohd, B. (2008) Textural Characteristics of Activated Carbons Prepared from Oil Palm Shells Activated with ZnCl2 and Pyrolysis Under Nitrogen and Carbon Dioxide. Journal of Physical Science, 19, 93–104.

Olivares-Marín, M., Fernández-González, C., Macías-García, a., and Gómez-Serrano, V. (2006) Preparation of activated carbon from cherry stones by chemical activation with ZnCl2. Applied Surface Science, 252, 5967–5971.

Qin, F.-X., Jia, S.-Y., Liu, Y., Li, H.-Y., and Wu, S.-H. (2014) Adsorptive removal of bisphenol A from aqueous solution using metal-organic frameworks. Desalination and Water Treatment, 1–10.

Salman, J.M. (2013) Preparation of mesoporous-activated carbon from branches of pomegranate trees: Optimization on removal of methylene blue using response surface methodology. Journal of Chemistry, 2013.

Shaarani, F.W. and Hameed, B.H. (2010) Batch adsorption of 2,4-dichlorophenol onto activated carbon derived from agricultural waste. Desalination, 255, 159–164. Elsevier B.V.

Shuit, S.H., Tan, K.T., Lee, K.T., and Kamaruddin, A.H. (2009) Oil palm biomass as a sustainable energy source : A Malaysian case study. Energy, 34, 1225–1235. Elsevier Ltd.

Snyder, S. a., Adham, S., Redding, A.M., Cannon, F.S., DeCarolis, J., Oppenheimer, J., Wert, E.C., and Yoon, Y. (2007) Role of membranes and activated carbon in the removal of endocrine disruptors and pharmaceuticals. Desalination, 202, 156–181.

Sui, Q., Huang, J., Liu, Y., Chang, X., Ji, G., Deng, S., Xie, T., and Yu, G. (2011) Rapid removal of bisphenol A on highly ordered mesoporous carbon. Journal of Environmental Sciences, 23, 177–182. The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Sulaiman, F., Abdullah, N., Gerhauser, H., and Shariff, A. (2011) An outlook of Malaysian energy , oil palm industry and its utilization of wastes as useful resources. Biomass and Bioenergy, 35, 3775–3786. Elsevier Ltd.

Tan, I. a W., Ahmad, a. L., and Hameed, B.H. (2009) Adsorption isotherms, kinetics, thermodynamics and desorption studies of 2,4,6-trichlorophenol on oil palm empty fruit bunch-based activated carbon. Journal of Hazardous Materials, 164, 473–482.

Tanaka, R., Wan Rosli, W.D., Magara, K., Ikeda, T., and Hosoya, S. (2004) Chlorine-free bleaching of kraft pulp from oil palm empty fruit bunches. Japan Agricultural Research Quarterly, 38, 275–279.

Tchobanoglous, G., Burton, F.L., and Stensel, H.D. (no date) Wastewater Engineering.

84

Tsai, W., Hsu, H., Su, T., Lin, K., and Lin, C. (2006) Adsorption characteristics of bisphenol-A in aqueous solutions onto hydrophobic zeolite. 299, 513–519.

Tsai, W., Lai, C., and Su, T. (2006) Adsorption of bisphenol-A from aqueous solution onto minerals and carbon adsorbents. 134, 169–175.

Tsai, W.T., Chang, C.Y., Ing, C.H., and Chang, C.F. (2004) Adsorption of acid dyes from aqueous solution on activated bleaching earth. Journal of Colloid and Interface Science, 275, 72–78.

Wu, F.C., Tseng, R.L., and Juang, R.S. (2005) Comparisons of porous and adsorption properties of carbons activated by steam and KOH. Journal of Colloid and Interface Science, 283, 49–56.