Effect of activation conditions on the pinang frond based activated carbon performance in dyes removal.

(1)

Faculty of Mechanical Engineering

EFFECT OF ACTIVATION CONDITIONS ON THE

PINANG FROND BASED ACTIVATED CARBON

PERFORMANCE IN DYES REMOVAL

Mohd Azhar Bin Ahmad

Master of Science in Mechanical Engineering

(2)

EFFECT OF ACTIVATION CONDITIONS ON THE PINANG FROND

BASED ACTIVATED CARBON PERFORMANCE IN DYES REMOVAL

MOHD AZHAR BIN AHMAD

A thesis submitted

in fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering

Faculty of Mechanical Engineering

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

(3)

DECLARATION

I hereby declare that this thesis entitled ―Effect of Activation Conditions on The Pinang Frond Based Activated Carbon Performance in Dyes Removal‖ is the result of my own research except as cited in the references. The thesis has not been accepted for any degree and is not concurrently submitted in candidature of any other degree.

Signature :………..

Name : MOHD AZHAR BIN AHMAD Date : 25th AUGUST 2014

(4)

APPROVAL

I hereby declare that I have read this thesis and in my opinion this thesis is sufficient in terms of scope and quality for the award of Master of Mechanical Engineering.

Signature : ………. Supervisor Name : SAFARUDIN GAZALI HERAWAN Date : 25th AUGUST 2014

(5)

DEDICATION

(6)

i ABSTRACT

The production of activated carbon from agriculture waste offers both economical and environmental advantages. This study aims to prepare a novel pinang frond based activated carbon (PFAC) using a single-step physical activation method for removal of methylene blue (MB) and remazol brilliant blue R (RBBR) dyes from aqueous solution. The PFAC was produced at various activation conditions; i.e. activation temperature (600-900oC), activation time (1-7 hours) and CO2 flow rate (150-600 mL/min). All PFAC samples

prepared have large surface area (<576 m2/g) and consist of pore in mesopore region. The experimental design results obtained via face centered composite design (FCCD) revealed that activation temperature, activation time and CO2 flow rate were important variables that

influence the dyes removal performance by PFAC. The optimum conditions obtained for preparing PFAC were 867°C, 6.0 hour and 476 mL/min for activation temperature, activation time and CO2 flow rate, respectively. This optimum sample gave high surface

area of 992.0 m2/g, pore volume of 0.551 mL/g and fixed carbon content of 80.24%. MB and RBBR removal of 96.8% and 76.4%, respectively were achieved by using this sample. Adsorption equilibrium and kinetic data of MB adsorption by PFAC were fitted well with Langmuir isotherm and pseudo-first-order kinetic model, respectively. On the other hand, the adsorption equilibrium and kinetic data of RBBR by PFAC were fitted well with Freundlich isotherm and the pseudo-second-order kinetic model, respectively.

(7)

ii ABSTRAK

Pengeluaran karbon teraktif daripada sisa pertanian menawarkan dua kelebihan iaitu dari segi ekonomi dan alam sekitar. Kajian terbaru ini bertujuan untuk menyediakan upih pinang berasaskan karbon teraktif (UPKT) menggunakan kaedah pengaktifan fizikal satu langkah untuk penyingkiran pewarna metilina biru (MB) dan remazol berkilau biru R (RBBR) daripada larutan akuas. UPKT ini dihasilkan pada keadaan pengaktifan yang pelbagai; suhu pengaktifan (600-900oC), masa pengaktifan (1-7 jam) dan kadar aliran CO2

(150-600 mL/min). Kesemua UPKT yang terhasil mempunyai luas permukaan yang besar (576 m2/g) serta liang daripada kumpulan mesoporos. Keputusan daripada rekabentuk eksperimen menggunakan rekabentuk komposit berpusat muka mendapati suhu pengaktifan, masa pengaktifan dan kadar aliran CO2 merupakan parameter yang penting

dalam mempengaruhi kecekapan UPKT menyingkirkan pewarna. Keadaan optimum bagi penyediaan UPKT adalah 867oC, 6.0 jam dan 476 mL/min masing-masing untuk suhu pengaktifan, masa pengaktifan dan kadar aliran CO2. Sampel optimum ini mempunyai luas

permukaan 992.0 m2/g dan isipadu liang 0.551 mL/g. Penyingkiran MB dan RBBR masing-masing adalah 96.8% dan 76.4% telah diperolehi dengan menggunakan sampel ini. Data penjerapan keseimbangan dan kinetik untuk penjerapan MB oleh UPKT telah menepati model isoterma Langmuir dan tertib kinetik pseudo-pertama. Data keseimbangan dan kinetik untuk penjerapan RBBR oleh PFAC pula telah menepati model isoterma Freundlich dan tertib kinetik pseudo-kedua.

(8)

iii

ACKNOWLEDGEMENT

All praises to Allah the Almighty for giving me the strengths, guidance and patience in completing this thesis. My deepest appreciation goes to Mr. Safarudin Gazali Herawan for being a very helpful supervisor for this project. His valuable suggestion and encouragement enabled me to handle this project with confidence. I also would like to express my gratitude to my co-supervisor, Dr Ahmad Anas Yusof for his guidance and knowledge throughout my research progress.

I would like to extend my appreciation for all lecturers, technicians and administrative staffs in the department for their invaluable assistance. For the financial support, I would like to thank Ministry of Higher Education and UTeM for awarding me with MyBrain scholarship. I would also like to thank School of Chemical Engineering, Universiti Sains Malaysia for providing me the research facilities.

Last but not least, my deepest appreciation goes to my father; Hj Ahmad Harun, my mother; Hajjah Azizah Mohd Nor, my parent in law; Hj Wan Ahmad Rosli and Hajjah Faridah, my wife; Siti Khadijah and my daughter; Nailah Zinnirah. Their love and support have given me the strength and spirit to the completion of this thesis. Thank you so much.

Mohd Azhar Bin Ahmad August 2014

(9)

TABLE OF CONTENT

DECLARATION i

APPROVAL ii

DEDICATION iii

ABSTRACT i

ABSTRAK ii

ACKNOWLEDGEMENT iii

TABLE OF CONTENT iv

LIST OF TABLES vii

LIST OF FIGURES ix

LIST OF APPENDICES xi

LIST OF ABBREVIATIONS xii

LIST OF SYMBOLS xiii

LIST OF PUBLICATIONS xiv

CHAPTER 1 1

INTRODUCTION 1

1.1 Background of study 1

1.2 Problem statement 2

1.3 Pinang (Areca catechu) frond 3

1.4 Research objectives 4

1.5 Organization of the thesis 5

CHAPTER 2 6

LITERATURE REVIEW 6

2.1 Utilization of agriculture waste 6

2.2 Pyrolysis via activation process 7

2.3 Activated carbon adsorption 10

2.3.1 Pore classification 16

(10)

2.3.3 Dyes classification and application 18

2.4 Design of experiment (DoE) 20

2.5 Adsorption studies 22

2.5.1 Adsorption isotherms 23

2.5.2 Adsorption kinetics 24

CHAPTER 3 26

MATERIALS AND METHODS 26

3.1 Materials 26

3.2 Experimental equipment 27

3.3 Preparation of PFAC 30

3.4 Characterization system 33

3.4.1 Proximate analysis 33

3.4.2 Scanning electron microscopy 34

3.4.3 Surface area analysis 34

3.5 Batch adsorption studies 35

3.5.1 Adsorption isotherm 37

3.5.2 Batch kinetic studies 37

3.6 Experimental design for preparation of PFAC 38

CHAPTER 4 41

RESULT AND DISCUSSION 41

4.1 Characterization of activated carbon 41

4.1.1 Proximate analysis 41

4.1.2 Surface morphology 45

4.1.3 Surface area and pore characteristics 51

(11)

4.2 Experimental design 61

4.3 Optimization of operating parameters 67

4.4 Optimum PFAC pyrolysis conditions and adsorption studies 68

4.4.1 Adsorption isotherm 68

4.4.2 Batch kinetic studies 71

CHAPTER 5 76

CONCLUSION AND RECOMMENDATION 76

5.1 Conclusions 76

5.2 Recommendations 77

REFERENCES 78

APPENDIX A 93

APPENDIX B 94

APPENDIX C 105

APPENDIX D 107

APPENDIX E 109

APPENDIX F 111

(12)

vii

LIST OF TABLES

TABLE TITLE PAGE

2.1 Agricultural wastes used to prepare activated carbons 11 2.2 Characteristics of activated carbon produced from various precursors 15

2.3 Dyes classifications 18

3.1 Samples designation 32

3.2 Independent variables and their coded levels for the FCCD 38

3.3 Experimental design matrix 39

4.1 Proximate analysis for activation temperature 42

4.2 Proximate analysis for Activation time 43

4.3 Proximate analysis for CO2 flow rate 44

4.4 Pore characteristics and yield of the PFAC for activation temperature 51 4.5 Pore characteristics and yield of the PFAC for activation time 52 4.6 Pore characteristics and yield of the PFAC for CO2 flow rate 53

4.7 Dyes removal by PFAC samples at equilibrium for activation temperature

(13)

viii

4.9 Dyes removal by PFAC samples at equilibrium for CO2 flow rate 59

4.10 Matrix for PFAC preparation variables and responses 61

4.11 ANOVA analysis for MB removal for PFAC 63

4.12 ANOVA analysis for RBBR removal for PFAC 63

4.13 Model validation for PFAC prepared for MB and RBBR removal 68 4.14 Langmuir and Freundlich isotherm model parameters and correlation

coefficients for adsorption of MB on PFAC

4.15 Langmuir and Freundlich isotherm model parameters and correlation coefficients for adsorption of RBBR on PFAC

4.16 Pseudo-first-order and pseudo-second-order kinetic model parameters for the adsorption of MB dye on PFAC

4.17 Pseudo-first-order and pseudo-second-order kinetic model parameters for the adsorption of RBBR dye on PFAC.

(14)

LIST OF FIGURES

TABLE TITLE PAGE

1.1 Picture of (a) pinang tree and (b) pinang frond 4

2.1 Two-dimensional representation of carbon activation 8 2.2 Schematic of internal pore structure in activated carbon 10 2.3 Scanning electron micrographs; (a) MP; and (b) MP activated carbon 13 2.4 Schematic representations of the different types of pores in an

activated carbon particle 17

2.5 Face centered composite design 21

3.1 Experimental setup for PFAC preparation 28

3.2 Schematic diagram of the experimental setup 29

3.3 Vertical tubular furnace and reactor 30

3.4 Simultaneous thermogravimetric analyzer (Perkin Elmer 6000 STA) 33

3.5 ASAP 2020 Micromeritics 34

3.6 Water bath shaker 35

3.7 Double-beam UV-Visible spectrometer 36

4.1 SEM images (a) pinang frond, (b) PFAC600C, (c) PFAC700C, (d)

(15)

4.2 SEM images (a) PFAC1T, (b) PFAC3T, (c) PFAC5T and (d) PFAC7T 48

4.3 SEM images (a) PFAC150F, (b) PFAC300F, (c) PFAC450F and (d)

PFAC600F 50

4.4 Plot of (a) MB and (b) RBBR percent removal by PFAC prepared at

various activation temperature 55

4.5 Plot of (a) MB and (b) RBBR percent removal by PFAC prepared at

various activation times 57

4.6 Plot of (a) MB and (b) RBBR percent removal by PFAC prepared at

different CO2 flow rate 60

4.7 Response surface plot of MB removal of PFAC; (a) Effect of activation temperature and time, CO2 flow rate = 375 mL/min; (b)

Effect of activation temperature and CO2 flowrate, t = 4h; (c) Effect

of activation time and CO2 flow rate, temperature = 750oC. 65

4.8 Response surface plot of RBBR removal of PFAC; (a) Effect of activation temperature and time, CO2 flow rate = 375 mL/min; (b)

Effect of activation temperature and CO2 flow rate, t = 4h; (c) Effect

of activation time and CO2 flow rate, temperature = 750oC. 66

4.9 Plots of pseudo-first-order for MB adsorption on PFAC 72 4.10 Plots of pseudo-second-order for MB adsorption on PFAC 73 4.11 Plots of pseudo-first-order for RBBR adsorption on PFAC 74 4.12 Plots of pseudo-second-order for RBBR adsorption on PFAC 75

(16)

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Table properties of dyes 93

B BET surface area report 94

C Graph result of proximate analysis 105

D Graph result of pore and yield analysis 107

E Table of initial dyes concentration and contact time 109 F Langmuir and Freundlich isotherms for MB adsorption onto

PFAC

111

G Langmuir and Freundlich isotherms for RBBR adsorption onto PFAC

(17)

xii

LIST OF ABBREVIATIONS

AC Activated carbon

BET Brunauer-Emmett-Teller DoE Design of experiment

FCCD Face centered composite design

IUPAC International Union of Pure and Applied Chemistry

MB Methylene blue

PF Pinang frond

PFAC Pinang frond based activated carbon RBBR Remazol brilliant blue R

RSM Response surface methodology SEM Scanning electron microscopy

STA Simultaneous thermogravimetric analyzer UPKT Upih pinang berasaskan karbon teraktif UNEP United Nations Environment Programme

(18)

xiii

LIST OF SYMBOLS

Equilibrium concentration of adsorbate mg/L

Dp _{Average pore diameter} _nm

Equilibrium rate constant of pseudo-first-order sorption 1/h Langmuir adsorption constant related to the free energy

adsorption L/mg

Freundlich isotherm constant mg/g(L/mg)1/n

The rate constant of pseudo-second-order sorption g/mg h

nF Heterogeneity factor -

Amount of adsorbate adsorbed at equilibrium mg/g Monolayer adsorption capacity of the adsorbent mg/g Amount of adsorbate adsorbed at any time mg/g

Qo Monolayer adsorption capacity mg/g

R2 Correlation coefficients -

SBET _{BET surface area} _m2_/g

t Time h

Volume of the solution L

VT _{Total pore volume} _cm3_/g

w The dry weight of precursor g

wc Dry weight of final PFAC g

Mass of adsorbent used g

(19)

xiv

LIST OF PUBLICATIONS

Journal publications

Ahmad, M. A., Herawan, S. G. & Yusof, A. A. (2014). Equilibrium, Kinetics, and Thermodynamics of Remazol Brilliant Blue R Dye Adsorption onto Activated Carbon Prepared from Pinang Frond. ISRN Mechanical Engineering, 2014.

Ahmad, M. A., Herawan, S. G. & Yusof, A. A. (2014). Effect of Activation Time on the Pinang Frond Based Activated Carbon for Remazol Brilliant Blue R Removal. Journal of Mechanical Engineering and Sciences.

Herawan, S. G., Ahmad, M. A., Putra, A. & Yusof, A. A. (2013). Effect of flow rate on the pinang frond-based activated carbon for methylene blue removal. The Scientific World Journal, 2013.

Conference paper

M.A. Ahmad, S.G. Herawan, A.A. Yusof (2013). Effect of Activation Time on the Pinang Frond Based Activated Carbon for Remazol Brilliant Blue R Removal, Proceeding of Malaysian Technical Universities Conference on Engineering and Technology (MUCET 2013), MS Garden Hotel, Kuantan, Pahang, 3-4 Dec 2013.

(20)

1 CHAPTER 1

INTRODUCTION

1.1 Background of study

Agrowaste pyrolysis is a method to convert biomass and organic waste into diverse products by heating in the absence of oxygen. Understanding the pyrolysis process is crucial in order to fully grasp the pyrolytic-cracking mechanism of a specific ligno-cellulosic waste (Lopez-Velazquez et al., 2013). Pyrolysis process using oxidizing gases such as carbon dioxide (CO2) or steam (H2O) is known as activation process and the final product is known as activated

carbon (Sekirifa et al., 2013).

Activated carbon is amorphous carbonaceous material which exhibits a high degree of porosity, adsorption capacity and surface area. Activated carbon has ability to adsorb pollutant in wastewater such as dyes and heavy metal. Nearly 80% (~300,000 ton/year) of the total activated carbon is consumed for liquid-phase application in wastewater treatment. (Bansal and Goyal, 2005). The high raw material cost of those commercial coal based activated carbons has limited their application (Gupta and Suhas, 2009). Other sources of cheap activated carbon‘s precursor have also been investigated especially from agricultural by-products.

Activated carbons have been produced from banana stalk (Bello et al., 2011), bamboo species (González and Pliego-Cuervo, 2013), coffee husk (Ahmad and Rahman, 2011), oil palm

(21)

stone (Lua and Guo, 2000), date pits (Bouchelta et al., 2012) oil palm shell (Herawan et al., 2013, Yusof et al., 2012) and parkinsonia aculeata wood (Nunell et al., 2012). In this work, an attempt was made to produce a novel pinang frond based activated carbon (PFAC) via activation process. This study tested the hypothesis that activation conditions play a key role in the characteristic of PFAC as well as PFAC performance in dyes removal. To test this hypothesis, the activation temperature, activation time and CO2 flow rate were used as parameters for

activation conditions with dyes removal as the performance indicator.

1.2 Problem statement

The textile industry has become one of the greatest sources of liquid effluent that contaminated with various kinds of dyes due to the high quantities of water used in the dyeing processes. Around 10,000 of different dyes are produced annually which weighing approximately 0.7 million tons (Senthilkumaar et al., 2006). However 10–15% of these dyes are left as effluent during dyeing process (Murugesan et al., 2007). Dyes effluent has complex aromatic molecular structures which make it difficult to biodegrade and decolourize. This effluent contains colour and a large amount of suspended organic solids (El-Sharkawy et al., 2007). Hence, the presence of dyes into water bodies constitute a source of water pollution that cannot be neglected (Dulman and Cucu-Man, 2009).

Activated carbon adsorption has been proved to be suitable for dyes removal in terms of its simplicity of design, high efficiency and ease of operation. However, the raw material for commercial activated carbon of bituminous coal is very expensive and non-renewable source

(22)

which cause to the high price of the product. As such, there is a need to produce activated carbon from alternative material that is cheaper, renewable and readily available.

The amount of agriculture wastes generated in Malaysia is increasing enormously. Conversion of these agriculture wastes into activated carbons which can be used as adsorbents in dyes wastewater treatment would add value to these agricultural commodities, help reduce the cost of waste disposal and provide a potentially cheap alternative to existing commercial activated carbons. This study investigates the feasibility of preparing PFAC for application in removing basic dye (methylene blue) and reactive dye (remazol brilliant blue R) from aqueous solution.

1.3 Pinang (Areca catechu) frond

Pinang or Areca catechu in its scientific name is a tropical tree that belongs to Arecaceae family. It mainly grows from East Africa to the Arabian Peninsula across tropical Asia to the central Pacific and New Guinea. Traditionally, the main part used from this tree is the nut (or seed endosperm) where it is chewed as a stimulant masticatory. The practice can be found usually in India and some parts of Asia. Utilization of the frond is lacking and it is usually disposed (Staples and Bevacqua, 2006). In fact, there is no research work on the utilization of pinang frond as activated carbon adsorbent in the previous literature. Therefore, in this work pinang frond was used for activated carbon production.

(23)

Figure 1.1: Picture of (a) pinang tree and (b) pinang frond

1.4 Research objectives

i. To prepare pinang frond based activated carbon (PFAC) at various activation conditions; (i) temperature, (ii) time and (iii) CO2 flow rate.

ii. To characterize the PFAC in terms of proximate content, surface morphology, BET surface area, total pore volume, average pore diameter and yield production.

iii. To study the adsorption isotherm and kinetic for the methylene blue (MB) and remazol brilliant blue R (RBBR) dyes adsorbed onto optimized PFAC obtained from face centered composite design.

(24)

5 1.5 Organization of the thesis

This thesis consists of five chapters and each chapter represents an important build for the construction of the thesis. Chapter one presents background of study, problem statements and objectives of the study. Chapter two provides the general information regarding (i) utilization of agriculture waste, (ii) pyrolysis process via activation process and (iii) activated carbon adsorption. Chapter three explains the materials, experimental equipment, characterization method and batch adsorption studies. Chapter four presents the experimental results and discussion on the characterization of the PFAC prepared at various activation temperature, time and CO2 flow rate. Characterization performed on PFAC were proximate analysis, surface

morphology, BET surface area, total pore volume, average pore diameter and carbon yield. Furthermore the results on MB and RBBR dyes removal were also included. Subsequently, the face centered composite design (FCCD) was used to obtain the optimum PFAC‘s preparation conditions for both dyes removal. The optimized PFAC sample was used for adsorption isotherm and kinetic studies. Chapter five finally presents the conclusions that reflect the achievements of all the objectives which were obtained throughout the study as well as the recommendations for the future research.

(1)

xiv