The synthesis of Faujasite Zeolite from Locally available Erusu Kaolin clay sourced in Nigeria has been attempted using standard procedures which have proven sufficient upon slight modifications and reported in literature. The zeolite was characterized with Scanning Electron Microscopy, Fourier Transformed infrared spectroscopy (FTIR), X-ray Diffractometer and BET surface area analyzer. Forthwith, Adsorption of the hazardous cationic dye malachite green (MG) on the synthesized zeolite was investigated. Batch process variables for the adsorption of MG by Zeolite were determined. The mechanisms involved in the adsorption of MG by the sorbent were explored using isotherms models. The maximum equilibrium adsorption capacity was found to be 108.26 mg/g at 30˚C. It is noteworthy that the adsorption of MG was reduced (about 45%) at low pH (4) compared to that at high pH (12). Furthermore, among the other parameters affecting adsorption, a high MG adsorption capacity (about 54%) was observed at a maximum initial MG dye concentration of 200 mg/L compared to that at lower initial MG dye concentration (25 mg/L), indicating the dependency of sorption on the initial adsorbate concentration (CO) in the solution. The MG adsorption data indicate multilayer adsorption because the data were fit better by the Freundlich model (R2 >0.99) than by the Langmuir model. Surface diffusion was found to be a possible mechanism for the adsorption of MG by Zeolite. The study shed light on the potential of synthesized kaolinite derivative “Zeolite” as an efficient sorbent for cationic dye cleanup in wastewater treatment.

1. International Journal of Modern Research in Engineering & Management (IJMREM)
||Volume|| 1||Issue|| 5 ||Pages|| 07-13 ||May 2018|| ISSN: 2581-4540
www.ijmrem.com IJMREM Page 7
Synthesis of Faujasite Zeolite (Z) for Adsorption of Cationic Dye
from Textile Waste Water.
*A. G Olaremu, and A.O Adeola
Department of Chemical Sciences, Adekunle Ajasin University, Akungba-Akoko, Ondo State, Nigeria.
*Corresponding author: abimbolaremu@yahoo.com/ abimbola.olaremu@aaua.edu.ng
------------------------------------------------------ABSTRACT----------------------------------------------------
The synthesis of Faujasite Zeolite from Locally available Erusu Kaolin clay sourced in Nigeria has been
attempted using standard procedures which have proven sufficient upon slight modifications and reported in
literature. The zeolite was characterized with Scanning Electron Microscopy, Fourier Transformed infrared
spectroscopy (FTIR), X-ray Diffractometer and BET surface area analyzer. Forthwith, Adsorption of the
hazardous cationic dye malachite green (MG) on the synthesized zeolite was investigated. Batch process
variables for the adsorption of MG by Zeolite were determined. The mechanisms involved in the adsorption of
MG by the sorbent were explored using isotherms models. The maximum equilibrium adsorption capacity was
found to be 108.26 mg/g at 30˚C. It is noteworthy that the adsorption of MG was reduced (about 45%) at low
pH (4) compared to that at high pH (12). Furthermore, among the other parameters affecting adsorption, a high
MG adsorption capacity (about 54%) was observed at a maximum initial MG dye concentration of 200 mg/L
compared to that at lower initial MG dye concentration (25 mg/L), indicating the dependency of sorption on the
initial adsorbate concentration (CO) in the solution. The MG adsorption data indicate multilayer adsorption
because the data were fit better by the Freundlich model (R2 >
0.99) than by the Langmuir model. Surface
diffusion was found to be a possible mechanism for the adsorption of MG by Zeolite. The study shed light on the
potential of synthesized kaolinite derivative “Zeolite” as an efficient sorbent for cationic dye cleanup in
wastewater treatment.
KEYWORDS: Adsorption, Faujasite Zeolite, Freundlich, Fourier Transformed Infrared Spectroscopy, X-ray
Diffractometer.
I. INTRODUCTION
Zeolites are microporous hydrated crystalline solids (aluminosilicates) consisting of a regular system of pores
(channels) and cavities (cages) with diameters of molecular dimensions (0.3 to 1.4nm) (1.2). A large number of
zeolites are in existence; a handful are natural occurring while majority are synthesized. It was not until the
1930s and 1940s that scientists started to synthesize zeolites and hundreds of zeolites have been synthesized (3).
As a result of its unique properties, Zeolites have been found suitable for several chemical reactions and
industrial applications. Zeolites has been used in many applications such as ion exchange separation processes,
gas purification of industrial effluents, gas drying, Fluid catalytic cracking, water treatment etc. (4).
The inert nature of zeolites, unique properties and selectivity, can provide effective solutions for environmental
pollution by minimizing or removal of the pollutants by secondary treatment of wastewater. To optimum
performance, the adsorbent must possess high abrasion resistance, small pore size/diameter and thermal stability
which are sacrosanct to high surface area for sorption processes. Its unique pore structure promotes speedy
transport of the ions. Zeolite properties, such as structure, Si/Al ratio and pore size and distribution are
influenced by the certain synthesis parameters. Some of the process variables that affect the type of zeolite
formed by a particular synthetic procedure and precursor are: temperature, PH, crystallization time, gel
composition, sources of reagents and order of mixing (5).
Malachite green has been used to control pests and diseases in fish farms because of its ectoparasitic and
disinfectant properties. In addition, MG is used for dyeing silk, cotton, and leather. However, this dye can
pollute aquatic life via its carcinogenic and mutagenic properties, which have been confirmed in animal model
studies (6-8). Synthetic dyes have been used in the textile, paper, rubber, plastics, cosmetics, pharmaceutical and
food industries. Today, there are over 10,000 dyes available commercially, most of which are recalcitrant and
not easily degradable due to their complex aromatic molecular structure (9).
The extensive use of dyes often poses pollution problems in the form of colored wastewater effluents in aquatic
systems. Small quantities of dyes can color large water bodies, which affects aesthetic nature and reduces light
penetration with adverse effect on photosynthesis. Furthermore, some dyes are toxic or mutagenic and
carcinogenic due to the presence of metals, chlorides, etc., in their structure. Subsequently, dyeing leaves a

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strongly colored dyeing bath highly loaded in organic compounds along with highly concentrated mineral salts
and often indiscriminately discharged in the municipal wastewater treatment plant (10,11). Several treatment
technologies have been developed to for the removal of wastewater. These treatment options include biological,
physio-chemical, membrane filtration, ozonation advanced oxidation and integrated treatment processes (12).
However, these processes face several technical and economical limitations such as cost and production of
sludge (13). Adsorption process is an economical treatment method due to its performance and ease of
operation. Adsorption technology has attracted interest as an effective and alternative treatment method and
possess many merits over the existing conventional process. This process is not only economic and feasible but
also produces high quality of water (14). Batch adsorption experiments are used easily in the laboratory for the
treatment of small volume of effluents, but less convenient for use on industrial scale, where large volumes of
wastewater are continuously generated. Batch adsorption provides certain preliminary information such as pH
for maximum adsorption, particle size for optimum adsorption of dye ions (15).
Faujasite class of zeolites (zeolite X and zeolite Y) are known as stable and rigid structure with the large void
space. This group of zeolites plays a significant role in the unprecedented gasoline yield commonly obtained
from the fluid catalytic cracking of gas oil. In addition, faujasite type zeolites have a regular opening aperture of
about 8A, which is large enough to accommodate typical large molecules commonly found in gas oil during
catalytic cracking and refining operations. Previous attempts to produce zeolite from clay resulted in the
formation of small pore sized zeolite D-type. The presence of potassium ion in the clay, reagents and leaching of
the adversely affected the synthesis of the zeolite of interest (5) Parameters such as Increase in pH, will lead to
less positive charges producing an increasing electrostatic attraction between the surfaces and the acid group.
This could be attributed to electrostatic effect that causes the adsorption capacity to increase with decrease in
radius (15). This research will show the interaction effects of the parameters pH, dye concentration and
adsorbent dose on the dye adsorption. In this research, synthesis of zeolite X from kaolin clay carried and its
potential for sorbing selected cationic dyes were also investigated.
II. MATERIALS AND METHODS
Materials: The cationic dyes malachite green (MG - 96%) were used as the adsorbate in this study and obtained
from Sigma-Aldrich (Germany). All the chemicals used were of analytical reagents grade.
Synthesis of Faujasite Zeolite : The kaolinite clay used as precursors for the production of the targeted zeolite
was obtained in Erusu Akoko (Longitude- 5˚
31′E and Latitude 7˚
45′N). The beneficiation of the clay, conversion
to metakaolin and acid treatment (Leaching) were carried by method previous reported (16) with slight
modifications. The kaolin was oven dried at 120˚
C overnight leading to the removal of undesirable volatile
organic matter. The residue left after decomposition and removal of organic matter is called „Metakaolin‟. 20g
of the metakaolin was diluted in 250ml of 2M H2SO4 and stirred on the magnetic stirrer for 4hours at 80˚
C. The
solid was recovered via filtration and dried at a temperature of 80˚
C for 24 hours. The dealumination of
metakaolin by leaching with sulphuric acid is to meet the silica-alumina ratio required for the targeted Zeolite
(Z). The dried solid was mixed with NaOH (1: 1.2) and pulverized with ball miller at 300 rpm for 30 minutes to
ensure homogeneity. The solid was heated at fusion temperature of 550˚
C for 30 minutes and mixed with
distilled water, stirred at room temperature (curing) for 24 hours. The solid material was washed and filtered 10
times, finally oven dried at 80˚
C for 24hours.
Characterization: The physicochemical characteristics of the adsorbent materials are important in evaluating
the mechanism of sorption onto the surface of the adsorbent. The Fourier Transform Infrared (FT-IR) spectra of
natural and modified clay were recorded to examine the surface functional group using Nicolet Nexus 870 FT-
IR spectrometer in the region 400–4000 cm–1
with resolution of 4 cm–1
and ten interferograms was recorded for
the sample before malachite green loading. A FEI Quanta 450 scanning electron microscope (SEM) was used to
define the change in surface morphology of sorbent. The X-ray Diffraction technique is used to identify the
crystalline and amorphous phase of the sample.
Batch adsorption studies: Batch adsorption studies were performed by adding a fixed amount of adsorbent
(0.05 g) into 100-mL Erlenmeyer flasks. The concentration of MG dye (50 mg/L) was maintained in the 50-mL
solution, where the initial MG dye concentration was 40 mg/L. The MG dye solution pH (7) and particle size of
adsorbent (400μm) were also kept constant. The flasks were agitated in a temperature controlled shaking
incubator at 220 rpm and 30˚C until equilibrium was reached. Aqueous samples were taken from the shaker, and
the concentrations were analyzed at 616 nm using UV/Vis spectrophotometer (Shimadzu UV1700 Japan). The
experimental data for the adsorption of MG onto Z at initial dye concentrations ranging from 25 to 200 mg/L
(Table 1) were fitted with different adsorption isotherm models. In contrast, the batch parameters, i.e., pH (7),

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temperature (30 C), adsorbent dose (0.05 g/L), shaking speed (220 rpm), and contact time (40 min), were kept
constant. We used the Langmuir and Freundlich models to determine the adsorption capacity of the synthesized
zeolite were determined using the mass balance equation;
(1)
Where Co (mg/L) is the initial concentration, Ce (mg/L) is the equilibrium solute concentration, Vo is the initial
volume and Sm is the mass (g) of the zeolite (Z) (17)
Data Analysis: Two model of isotherm where used to fit the sorption data. The Freundlich model (FM), which
is used commonly for quantifying dye sorption equilibria for soils, has the following form;
Qe= KfCN
e (2)
where Qe is the solid-phase concentration (µg/g) and Ce is the liquid-phase equilibrium concentration (µg/L). Kf
is the sorption capacity-related parameter (µg/g)/(µg/L) n
) and n is the isotherm nonlinearity index, an indicator
of site energy heterogeneity determined by linear regression of log-transformed data as shown below;
log Qe = log Kf + Nlog Ce (3)
The Langmuir model (LM) describing such site-limiting sorption equilibrium has the following form.
m
:
1
L
e
L
q K Ce
Langmuir q
K Ce


(4)
where qmax is the maximal sorption capacity and KL is a solute–surface interaction energy-related parameter
(15,17)
III. RESULTS AND DISCUSSION
Characterization of the Faujasite Zeolite: The XRD Pattern revealed the successive synthesis of Zeolite along
with anatase (TiO2) and quartz (SiO2) which was picked by the equipment. The anatase and quartz however
could only have originated from the kaolin showing that the dealumination process is not 100% efficient. The
Zeolite, anatase and quartz forms the crystalline phase however the TiO2 and SiO2 are undesirable co-products
which was identified by the X-ray Diffractogram (18) The plausible reason for the formation of undesirable co-
products and by-products during Zeolite Synthesis are attributed to the following (a) Silica-alumina ratio (b)
ageing of the gel (c) temperature and time of reaction (d) Lack proper homogenization (e) and Alkalinity etc
(19). However, the percentage of Zeolite produced is >55% and the fraction is considered more than enough for
the vast applications of zeolite including adsorptive clean-up of cationic dyes from textile waste water. It has
been reported that FTIR spectrum can be used to prove the existence of zeolite frameworks. In this regard, a
comparison was performed in Figure 2 on the zeolite (Z) and the kaolin sample. The band formed at 3450-
3466cm-1
on the zeolite confirmed the attachment of hydroxyl groups to the zeolite framework. The 1640cm-1
band indicates the presence of adsorbed water on zeolite, a typical deformation band. The band at about
1000cm-1
is probably due to internal tetrahedral zeolite structure vibration of asymmetrical stretch (nasym),
whereas the band at 1090cm-1
is caused by asymmetrical stretch of external linkages. The band is conceived by
the internal tetrahedral vibration band and identified by the slight deviation of the band line at higher wave
number (after 1090cm-1
). The bands at the range of 720-650cm-1
show the symmetrical stretch vibrations of the
internal tetrahedral structure whereas the bands at 650-500cm-1
show the vibration of the double ring of external
linkages. A relatively weak band in the region of 1400-1500cm-1
is probably due to vibrations near non-zeolites
phases, those that are not converted to zeolite. In this case this is contributed from hydroxysodalite phase. (20)
Particle size and surface area play an important role determining the quality of zeolite product produced by the
hydrothermal fusion process. The effect of this process on the morphologies of the various samples were studied
by scanning electron micrograph (SEM) (Figure 3). The SEM images revealed that Zeolite (Z) particle was a
uniform ball with a diameter of less than 1 micron, and it was smaller and more regular than the native kaolin.
The bulkiness noticeable in the native kaolin was drastically removed and the surfaces became clearer. This has
significant positive impact on the amount of active sites available for sorption of malachite green.
Another characteristics of the zeolite that was studied is the surface area as larger surface area will result in a
better adsorption performance of the zeolite during the adsorption process (21). Results from the BET surface
area analyzer shows that zeolite product has value of 32.8m2
/g, which is more than three times the surface area
value of untreated kaolin (9.8 m2
/g).

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Figure 1. XRD Analysis of the Synthesized Faujasite Zeolite and Natural Clay
Figure 2: FTIR spectrum of the Natural Clay and Synthesized Faujasite Zeolite
Figure 3: SEM image of (a) Natural Kaolin (b) Synthesized Faujasite Zeolite
Effect of the initial MG dye concentration on its adsorption by Faujasite Zeolite (Z): Figure 4a and 4b for
both Langmuir and Freundlich isotherm model reveals the pattern obtained from experimental data. The amount
of adsorbed MG dye (mg/g) increased with increasing initial dye concentration (CO) for both model of
adsorption. Figure 4a&b shows MG adsorption capacity,144.1 mg/g (74.85%), of Zeolite at a maximum initial
MG dye concentration of 200 mg/L compared to that at a lower initial MG dye concentration of 25 mg/L. Both
Langmuir and Freundlich model gave a good fit to the experimental data, however, the Langmuir model best fit
the sorption data with R2
> 0.95. The plots established correlation between the “Zeolite” adsorption capacity on
the initial adsorbate concentration in the solution. The data also buttress the fact that the increasing solute
concentration provides a significant driving force controlling the resistance to mass transfer between the liquid-
solid interphase.

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These results demonstrated that higher initial influent concentrations led to greater driving force for solute
transfer, lower concentration gradient on the other hand, lead to a slower transport due to a decrease in the
diffusion coefficient or mass transfer coefficient. Hence, at higher adsorbate concentration, it could be inferred
that the adsorbent achieved saturation more quickly, which resulted in lower equilibration time and adsorption
zone length (14, 15, 22).
Figure 4a: Sorption Isotherm plot for Langmuir Model
Figure 4b: Sorption Isotherm plot for Freundlich Model
Effects of pH on the adsorption of MG by Zeolite (Z): MG is a cationic dye and is positively charged in the
aqueous phase. Thus, MG is an ionic species, and its adsorption onto the “Z” surface is primarily influenced by
the surface charge of the adsorbent, which in turn is influenced by the solution pH. In this study, the effect of pH
on MG adsorption was studied, while the agitation speed, solution temperature, initial dye concentration,
amount of “Z” adsorbent, contact time, and particle size were kept constant.
The effects of pH were investigated over the pH range of 2 to 10 pH (Figure 6). MG adsorption was found to be
signifIcantly reduced (18.20 mg/g, 44.80%) at low pH (4) compared to that (25.40 mg/g, 52.45%) at high pH
(12). This can be attributed to the chemistry that the excess H+
ions at low pH can compete with the positive MG
ions for sorption sites. A contrasting finding was that at high pH, the positive charges at the solid-liquid
interface decrease and the adsorbent surface becomes negatively charged; this lead to improved MG dye
removal. Similar findings have been made and reported in literature for the adsorption of cationic dyes by rattan
sawdust.
0
20
40
60
80
100
120
140
160
0 50 100 150 200 250
MGAdsorptionCapacity{Cs,mg/g}
Equilibrum Concentration {Ce, mg/L}
NATURAL CLAY
SYNTHESIZED ZEOLITE
0
0.5
1
1.5
2
2.5
0 50 100 150 200 250
MGAdsorptionCaoacity{LogCs,mg/g}
Equilibrum Concentration {LogCe, mg/L}
NATURAL CLAY
SYNTHESIZED ZEOLITE

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(23,24,25).
Figure 5: Effect of pH on the adsorption of MG on Zeolite
IV. CONCLUSION
In this study, the batch adsorption conditions of MG by zeolite was determined and optimized considering
environmental and experimental variables such as pH and concentration. It is noteworthy that the adsorption of
MG was reduced (about 45%) at low pH (2) compared to that at high pH (12). Furthermore, among the other
parameters affecting adsorption, a high MG adsorption capacity (about 54%) was observed at a maximum initial
MG dye concentration of 200 mg/L compared to that at lower initial MG dye concentration (25 mg/L),
indicating the dependency of sorption on the initial adsorbate concentration (CO) in the solution. The maximum
equilibrium adsorption capacity of Faujasite was 144.1 mg/g at 30˚C. The multi-layer adsorption mechanism
often associated dominantly with physisorption could be said to define the interactions between malachite green
and zeolite and there are reports that share the same view (15). The potential for environmental clean-up via
adsorption of many cationic dyes such as Malachite green as used in this study was established and the need to
explore the interactions and mechanisms of adsorption of the synthesized zeolite and other types of textile dyes
with specific functionalities, will be a welcome contribution to the body of knowledge.
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