Comparison study of ammonium ions adsorption on zeolite activated carbon and amino functionalized silica in aqueous solutions

THAI NGUYEN UNIVERSITY OF AGRICULTURE AND FORESTRY NATIONAL CHIAO TUNG UNIVERSITY NGUYEN DUC MANH COMPARISON STUDY OF AMMONIUM IONS ADSORPTION ON ZEOLITE, ACTIVATED CARBON AND AMINO

THAI NGUYEN UNIVERSITY

OF AGRICULTURE AND FORESTRY

NATIONAL CHIAO TUNG

UNIVERSITY

NGUYEN DUC MANH

COMPARISON STUDY OF AMMONIUM IONS ADSORPTION ON ZEOLITE, ACTIVATED CARBON AND AMINO-FUNCTIONALIZED

SILICA IN AQUEOUS SOLUTIONS

BACHELOR THESIS

Study Mode : Full-time

Major : Environmental Science and Management

Faculty : International Programs Office

Batch : 2013 - 2017

Thai Nguyen, 2017

Thai Nguyen University of Agriculture and Forestry

Zeolite, Activated carbon and Amino-functionalized silica in aqueous solutions

2 Assoc Prof Nguyen Thi Ha Supervisor’signature

Abstract:

This study examined the capability of Amino-functionalized silica, Activated carbon and Zeolite, to remove ammonium ions from water Studies were conducted to examine the ammonium removal capacity of these three materials under various experimental conditions of contact time and ammonium concentration The adsorption materials were prepared and investigated by various techniques including Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) to examine the functional groups and surface areas, respectively The pseudo first-order, pseudo second-order kinetic models were used to describe the kinetic data The ammonium removal data for Amino functionalized silica and Activated carbon

most highly correlated with pseudo-first-order adsorption reaction model, whereas Zeolite was best fitted with pseudo-second-order model The Langmuir and Freundlich models were applied to describe the equilibrium isotherms for ammonium adsorption capaciy The findings showed that the adsorption of ammonium on the Activated carbon was best fitted with the Langmuir model,Zeolite was best fitted with the Freundlich model, Amino functionalized silica could be described by both Langmuir and Freundlich model The results also indicated a significant potential of the Amino functionalized silica as an alternative adsorbent material for ammonium removal from aqueous solutions

Amino-functionalized material, ammonium ion

me during the internship time

Secondly, I would like to express my sincere gratitude to Assoc Prof Nguyen Thi Ha, Faculty of Environmental Science, VNU University of Science, Ha Noi, Viet Nam Thanks for her guidance, encouragement and support throughout the entire study and complement of this thesis

I am thankful to Environmental Nanomaterial Laboratory of National Chiao Tung University for providing me facilities to conduct my research work I am also thankful to all members in the laboratory for their help during my internship course

Student

guy n c nh

TABLE OF CONTENTS

ACKNOWLEDGMENT i

LIST OF FIGURES iv

LIST OF TABLES v

LIST OF ABBREVIATIONS vi

PART 1 : INTRODUCTION 1

1.1 Research rationale 1

1.2 Research’s Objective 3

1.3 Research’s Contents 3

1.4 Research’s Scope 3

PART 2 : LITERATURE REVIEW 4

2.1 General introduction to ammonium nitrogen 4

2.2 Methods for removing ammonium form water 7

2.3 Basic of adsorption theory 9

2.4 Introduction of Activated Carbon 10

2.5 Introduction of Zeolite 14

2.6 Introduction of Amino functionalized silica 18

PART 3 : MATERIALS AND METHODOLOGY 20

3.1 Materials 20

3.2 Experimental methods 20

3.2.1 Synthesis Amino-functionalized silica 20

3.2.2 Prepare water sample 21

3.2.3 Investigate the adsorption capacity 21

3.2.4 Investigate the kinetic of ammonium adsorption 21

3.2.5 Investigate the isotherm of ammonium adsorption 22

3.2.6 Analysis Methods 22

PART 4 : RESULTS AND DISCUSSION 24

4.1 Adsorbents characterization 24

4.1.1 BET characterization 24

4.1.2 FTIR spectra 25

4.2 Results of ammonium removal capacity investigation 26

4.2.1 Effect of contact time 26

4.2.2 Effect of ammonium concentration 28

4.3 Results of Kinetic model and Isotherm model investigation 29

4.3.1 Results of Kinetic model investigation 29

4.3.2 Results of Isotherm model investigation 30

PART 5 : CONCLUSION AND RECOMMENDATION 34

5.1 Conclusion 34

5.2 Recommendation for future study 35

REFERENCES 36

LIST OF FIGURES

Figure.1: Ammonium chemical structure

Figure.2: Formation of Ammonium

Figure.3: Schematic Representation of (a) graphitizing and (b) non-graphitizing structure of carbon

Figure.4: Micropore, Mesopore and Macropore Regions of Activated Carbon

Figure.6: Secondary structure units of the zeolite

Figure.7: Synthesis Amino functionalized silica process

Figure.8: BET surface area of Amino functionalized silica, Zeolite and Activated carbon

Figure.9: FTIR spectra of Amino functionalized silica, Zeolite and Activated carbon Figure.10: Ammonium removal efficiency using Amino functionalized silica, Activated carbon and Zeolite

Figure.11: Effect of initial ammonium concentration to equilibrium adsorption

LIST OF TABLES

Table 1 Ammonium ion adsorption on some adsorbents

Table 2 Summarizes basic structural data of some common zeolite

Table 3 Kinetic parameters for ammonium removal using the pseudo-first-order

model and pseudo-second-order model

Table4 Isotherms constants for the ammonium exchange by three sample

LIST OF ABBREVIATIONS

BET : Brunauer–Emmett–Teller

FTIR : Fourier Transform Infrared Analysis

: Pseudo-first-order adsorption constant

: Pseudo-second-order adsorption constant

and n: Freundlich constant

: Lang-muir constant

: Adsorption capacity at equilibrium conditions

: Adsorption capacity at time t

: Correlation coefficient value

PART 1 : INTRODUCTION

1.1 Research rationale

Water is one of our most important natural resources However, Due to increased anthropogenic activities and thus increased waste generated which causes environmental pollution, supplying safe drinking water is the highest challenge of

communities during the current century(Moussavi et al 2011) For all practical

purposes, water pollution is the addition by humans of something to the water that alters its chemical composition, temperature, or microbial composition to such an extent that harm to aquatic life and on those who consume the water (Lioyd,1992)

One of the sources that cause water pollution is Nitrogen and its compounds Nitrogen compounds are very essential elements for living organisms However, the presence of excess Nitrogen compounds causes environmental pollution Agriculture activities are associated with use of fertilizers on a large scale, industrial wastewater, domestic wastewater which rich of Nitrogen compound discharged into the environment causing adverse effect to aquatic ecosystems Ammonia and ammonium ions are the more commonly encountered Nitrogen compounds in waste water, these nutrients in aquatic ecosystems cause diverse problems such as imbalance of natural ecological systems and increase of eutrophication, depletion of dissolved oxygen in surface waters which kills fishes and create septic condition, odor problems, increase risks to human health

(Carpenter et al 1998) Therefore, the control on them has vital importance for the

protection of public health

Several physicochemical and biological methods, including biological nitrification–denitrification, break-point chlorination, chemical precipitation, and air-stripping have

problems when using these methods such as: complex operations and biomass waste for biological methods, moreover the treatment of ammonium nitrogen wastewater of low organic content by a biological process usually needs to be supplemented with a

carbon source, which may add to the treatment cost (H Huang et al 2010) Higher

energy consumption and produce secondary pollution for Air stripping method

Currently, adsorption/ion exchange is believed to be a simple and effective technique for water and wastewater treatment and the success of the technique largely depends

on the development of an efficient adsorbent Adsorption/Ion-exchange process have been used in various fields in recent years, including the ammonium ions removal from wastewater due to their many unique characteristic, such as simple operations,

high treatment capacity, high removal efficiency, fast kinetics and low cost (Cooney et

al 1999; Kang et al 2004)

Activated carbon, Zeolite derived from different materials has been widely used for sequestering ammonium ions from aqueous solutions However, with the increase of industrial wastewater containing different concentrations of ammonium ions, there is a growing demand to develop new materials for the efficient removal of ammonium ions from aqueous environments rather than the high cost activated carbon in which its full-scale application has been limited (Zheng, Zhang, and Wang 2009) Recently,

considered as an efficient approach to adsorb various ions such as ammonium from

aqueous solutions (Soltani et al 2015)

Hence, in the present work, I studied the application of Amino-functionalized silica

removal capacity of this material in comparison with common adsorbent: activated carbon and zeolite

1.2 Research’s Objective

carbon, Zeolite and Amino-functionalized silica

purifying water

1.3 Research’s Contents

1) Literature review about ammonium and ammonium contaminated in water, its adverse effects on ecosystem and human health

2) Synthesis and investigate the characteristics of Amino-functionalized silica

3) Investigate the ammonium adsorption capacity of Amino-functionalized silica and compare with Activated carbon, Zeolite and Amino-functionalized silica under different experimental conditions in aqueous solution

1.4 Research’s Scope

The sample of contaminated solution that contains ammonium ion were prepared

in Environmental Nanomaterial Laboratory, Chiao Tung University, Taiwan The experimental process was done in the laboratory

PART 2 : LITERATURE REVIEW

2.1 General introduction to ammonium nitrogen

Ammonium is an important source of nitrogen for many plant species, However, it is also toxic to most crop species and is rarely applied as a sole nitrogen source The ammonium cation is a positively charged polyatomic cation with the chemical formula

Figure 1 Ammonium chemical structure

leguminous plants before it is utilized by humans Ammonia dissolves in water to form

acids and other nitrogencontaining molecules In aqueous solution, ammonia acts as a

according to the reversible reaction:

The double arrow in the equation indicates that an equilibrium is established between dissolved ammonia gas and ammonium ions ( When pKa = 9.3 ) The degree to which ammonia forms the ammonium ion depends on the pH of the solution If the pH is low ( pH<9.3), the equilibrium shifts to the right: more ammonia molecules are converted

into ammonium ions and vice versa (Adeva et al 2012; Graham and MacLean 1992)

Figure 2 Formation of Ammonium ion

Ammonium is an important nitrogen ion form in aqueous solution Its pollution mainly comes from different resource:

Agricultural: The primary agricultural sources include accidental releases of

ammonia-rich fertilizer during transport (because of vehicle accident, faulty hose connections, and human error); and livestock waste (from barnyards, feedlots, pastures, and rangeland)

Residential and Urban: Household use of ammonia-containing cleaning products,

on-lot septic systems, and improper disposal of ammonia products may contribute to nonpoint pollution

Atmospheric deposition: available data suggests nitrogen (directly and via rainfall)

constitutes a large portion of total nitrogenous inputs to estuarine and marine systems and a somewhat lesser portion of total N inputs to freshwater systems Ammonia in the

atmosphere is derived from combustion processes such as domestic heating, burning of municipal waste, and internal-combustion engines

The presence of normal levels of ammonium nitrogen usually does not have a direct effect on aquatic insects or fish However, excess levels of ammonium nitrogen

in water can create conditions that make it difficult for aquatic insects or fish to survive Some effects due to excess nitrogen resource are:

Eutrophication: The process by which a body of water acquires a high concentration

of nutrients, especially phosphates and nitrates These typically promote excessive growth of algae As the algae die and decompose, high levels of organic matter and the decomposing organisms deplete the water of available oxygen, causing the death of other organisms, and fishes

Toxicity: The presence of excess nitrogen compound in water also synonymous with

the formation of toxins nitrates and nitrites These toxins not only toxic to the living

thing but also harm to human health It can interfere with the ability of people red blood cells to transport oxygen Infants who drink water high in nitrates may turn

―bluish‖ and appear to have difficulty in breathing since their bodies are not receiving enough oxygen In addition, they also cause digestive diseases, skin diseases, even affects the brain and can be fatal

Odor problem: Excess plants and algae will also create conditions where organic

matter accumulates High densities of algae will create a condition where sunlight cannot reach very far into the water Since plants and algae require some sunlight, plants and algae not receiving sunlight will die off These dead plant materials will settle to the bottom of the water and bacteria that feed on decaying organic material

will greatly increase in numbers This causing water pollution and odor problems due

to the decomposition of algae and dead fish (Balci 2004)

2.2 Methods for removing ammonium form water

Commonly, nitrogen removal is achieved by a biological,nitrification–denitrification process, which is the using bacteria Bacteria remove nitrogen from wastewater by a two step biological processes: nitrification followed by denitrification

Nitrification The biological conversion of ammonium to nitrate nitrogen is called

nitrification Nitrification is a two-step process Bacteria known as Nitrosomonas convert ammonia and ammonium to nitrite Next, bacteria called Nitrobacter finish the

conversion of nitrite to nitrate.The reactions are generally coupled and proceed rapidly

to the nitrate form; therefore, nitrite levels at any given time are usually low

These bacteria known as ―nitrifiers‖ are strict ―aerobes,‖ meaning they must have free dissolved oxygen to perform their work Nitrification occurs only under aerobic conditions at dissolved oxygen levels of 1.0 mg/L or more At dissolved oxygen (DO) concentrations less than 0.5 mg/L, the growth rate is minimal Nitrification requires a long retention time, a low food to microorganism ratio (F:M), a high mean cell residence time The nitrification process produces acid This acid formation lowers the

pH of the biological population in the aeration tank and can cause a reduction of the

growth rate of nitrifying bacteria The optimum pH for Nitrosomonas and Nitrobacter

is between 7.5 and 8.5; most treatment plants are able to effectively nitrify with a pH

of 6.5 to 7.0 Nitrification stops at a pH below 6.0

Denitrification The biological reduction of nitrate ( ) to nitrogen gas ( ) by facultative heterotrophic bacteria is called Denitrification ―Heterotrophic‖ bacteria need a carbon source as food to live ―Facultative‖ bacteria can get their oxygen by taking dissolved oxygen out of the water or by taking it off of nitrate molecules

Denitrification occurs when oxygen levels are depleted and nitrate becomes the primary oxygen source for microorganisms The process is performed under anoxic conditions, when the dissolved oxygen concentration is less than 0.5 mg/L, ideally less

low water solubility, it escapes into the atmosphere as gas bubbles Free nitrogen is the major component of air, thus its release does not cause any environmental concern

For air stripping methods, that is a process by which a liquid, usually water or wastewater, is brought into intimate contact with a gas, usually air, so that some undesirable substances present in the liquid phase can be released and carried away by the gas (J Huang and Shang 2006) To specific, ammonia nitrogen exists in both

in dynamic equilibrium according the equation:

This equilibrium is controlled by the solubility product which varies with temperature Therefore, the relative concentrations of these two species depend on both the pH of the solution and the temperature In general, at a temperature of 20°C and a pH of 7 or below, only ammonium ions are present As the pH increases above 7, the chemical

equilibrium is gradually shifted to the left in favor of the ammonia gas formation At a

pH of about 11.5–12, only the dissolved gas is present, Then using ammunition or blowing techniques, ammonia will evaporate according to Henry's law

2.3 Basic of adsorption theory

 Denfinition:

Adsorption is a phase transfer process that is widely used in practice to remove substances from fluid phases (gases or liquids) It can also be observed as natural process in different environmental compartments The most general definition describes adsorption as an enrichment of chemical species from a fluid phase on the surface of a liquid or a solid The phenomenon of adsorption is essentially an attraction

of adsorbate molecules to an adsorbent surface

The solid material that provides the surface for adsorption is referred to as adsorbent; the species that will be adsorbed are named adsorbate By changing the properties of the liquid phase (e.g concentration, temperature, pH) adsorbed species can be released from the surface and transferred back into the liquid phase This reverse process is referred to as desorption

 Adsorption process:

Adsorption process occurs due to interaction force between adsorbent and adsorbate, that can be defined as physical or chemical adsorption We can distinguish between two types of adsorption process depending on which of these two force types plays the bigger role in the process

Physical adsorption is caused by Vander Waal’s forces However, this is weak forces, then links formed are not durable, easily broken In other words, with physical

adsorption, molecules of adsorbate and adsorbent will not create chemical bonding, which is only the condensation in phase transfer and held in absorbent surface by weak molecular linkage force Hence, it is reversible and heat of adsorption is low

Chemical process is caused by chemical bonding forces, which including strong linkage force as ion-binding force, covalent force that link molecules of adsorbate and adsorbent to form surface compounds Linkage energy of these force are very strong, thus links formed are durable Some characteristic of chemisorption is irreversible, it forms monomolecular layer, and requires activation energy

 Factors effecting adsorption:

In general, the adsorption efficiency is influenced by the following factors:

2.4 Introduction of Activated Carbon

Activated carbon, also known as activated charcoal, is a form of carbon that is composed of a group of materials including a wide range of carboneous materials known for its small sized pores and high surface area that ranges from 100-1500

(Kılıç et all 2012) The main properties of activated carbons include high

surface area, microcrystalline structures, high thermostability, low acid-base reactivity, high performance, high degree of surface reactivity and wide pore size distribution

These properties make activated carbon a unique and versatile material Therefore, activated carbon is preferred as adsorbent for adsorption There are five forms of activated carbon including granular, powders, extrudates, fibers and beads forms The most preferred form of activated carbon for adsorption process in aqueous solution is the granular form because it can be separated from aqueous solution easily without any purification process But the powder form requires separation from the solution In

addition, both granular and powder form can be used in gaseous phase (Yeganeh et all

2006)

Physical properties

In 1950, Franklin studied the structure of carbonized materials and noticed two different well defined types: non-graphitizing carbon and graphitizing carbon These differences in structure are obvious from the earliest stages of carbonization, and may

be attributed essentially to the formation at low temperatures (J Zhao et al 2009)

Generally, substances that have high ratio of hydrogen or low ratio of oxygen contents are called graphitizing carbon Its structure is more impact and neighboring crystallites have a strong tendency to lie in nearly parallel orientation, the crystallite growth in graphitizing carbon occurs by the gradual displacement of whole layer-planes or even

of groups of layer-planes The pre-orientation existing in the graphitizing carbons facilitate this process, enabling the rearrangement of the layer-planes to take place by small stages.( Figure.3,a)

While, the substances that have high ratio of oxygen or low ratio of hydrogen content are called non-graphitizing carbon The non-graphitizing carbonsdemonstrate a strong order of cross linking of crystallites during heating at low temperature, forming a

porous carbon This leads to a random orientation of the crystallites in a rigid, finely porous mass The crystallite growth is impeded both by the strong cross-linking between neighboring crystallites and by their random orientation (Figure.3,b)

Figure 3 Schematic Representation of (a) graphitizing and (b) non-graphitizing

structure of carbon

Activated carbon is much closer to graphite in properties and structure Graphite is composed of layers of fused hexagons held by weak Van der Waals force These layers are held by carbon–carbon bonds (Suenaga 2008) Regarding the structures, interlayer spacing in graphite is 0.335nm Activated carbon is a muddled form of graphite, as a result of the presence of impurities and the activation process The interlayer space in activated carbon ranges between 0.34nm and 0.35nm Activation temperatures and carbonization produced more enhanced structure Regarding the pore structures, it can be divided into three types: Micropores having a diameter less than

100 Angstroms Mesopores is between 100-1000 Angstroms and the Macropores is greater than 1000 Angstroms (Williams and Reed 2004)

Figure.4 Micropore, Mesopore and Macropore Regions of Activated Carbon

Chemical properties

The adsorption properties of activated carbon are determined by its pore size distribution and chemical composition of the raw material The content of natural raw materials consists of different ratio of lignin (produce macropore), cellulose (produce micropore) and hemicellulose and the quality of adsorption properties strongly

depends on this content (Mohamad Nor et al 2013)

Oxygen complex group is one of the most important functional group present on the surface of activated carbon It is formed from the reaction between carbon and oxygen that is present as a content of starting materials or from imperfect carbonization process The oxygen content has a significant impact on the size and arrangement of initial crystallites composed in carbonaceous adsorbents

Activated Carbon Production Process

Generally, activated carbon is manufactured by two essential activation methods, including physical (thermal) activation and chemical activation The characteristics of activated carbon involves; pore size distribution, shapes of the pores and surface chemistry which effectively depends on the nature of carbonaceous precursor,

activation methods and activation conditions (Kong et al 2013)

Physical or thermal activation is one of the activation methods and consist of two steps First step is called carbonization Carbonization is the conversion of carbonaceous precursor to char in the absence of oxygen at high temperature, followed

by the second step which is called gasification The resulted char is exposed to high temperature in the presence of gases In Chemical activation the starting materials (raw material) is impregnated with a strong dehydrating agent and then followed by Pyrolysis at high temperature to prepare activated carbon

Activated carbon can be prepared from many organic materials having a high content

of carbon like coal, wood, coconut shell, sugar cane and so on

2.5 Introduction of Zeolite

Zeolite include a group of hydrous aluminum-silicates, that have close similarities in chemical composition, geological association and mode of occurrence They can be described chemically as aluminum silicates There are seven group of zeolite species:

analcime, chabazite, gismondine, heulandite, natrolite, harmontome and stilbite In

each zeolite group, the cation are exchangeable within a particular framework and this results in variety of composition The order or disorder of silicon and aluminum ions

in the framework produce different symmetry and crystal systems which characterize