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Using Natural Stone Pumice in Van Region on Adsorption of Some Textile Dyes


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Toxic effect of textile dyes their increasing quantities in air, soil and water environments, because of growing of industrial actives, they must be taken into consideration since they harm to environment. We come across textile dyes in natural wetlands as result of uncontrolled industrial wasted. Textile dyes that can accumulate easily in their environments may show toxic effects. Pumice, accruing as result of volcanic events and durable against chemical factors, is a rock that has porous structure. Pumices have a porous structure because of sudden cooling of the rock and sudden leaving of gases a result of volcanic events. Thanks to these pores, pumices heat and sound insulation are quite high. The most distinctive feature of pumice from other rocks is that it has different colors and there is not crystal water in its porous structure. Adsorption studies are applied with Van Pumice at pH = 6, the adsorption mechanism and changing metal concentration. As result of these researches, it has been found that there are different adsorption movements at pH 6 between textile dyes and Van Pumice. The result of this study shows that the Pumice found in Lake Van gives a better fit for the Langmuir Isotherm (model) and the amount of adsorption increases with the temperature. It is thereby concluded that the Pumice located in Lake Van is a recommended adsorbent for filtering the used textile dye in aqueous medium.
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Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
Using Natural Stone Pumice in Van Region on Adsorption of Some
Textile Dyes
Ali Rıza KUL
, Veysel BENEK
, Ahmet SELÇUK
, Nilgün ONURSAL
Science Faculty of Yuzuncu Yil University, 65300, Van, Turkey
Faculty of Education Yuzuncu Yil University, 65300, Van, Turkey
Faculty of Education of Siirt University, 56100, Siirt, Turkey
Abstract: Toxic effect of textile dyes their increasing quantities in air, soil and water
environments, because of growing of industrial activities, they must be taken into
consideration since they give harm to the environment. We come across textile dyes in
natural wetlands as result of uncontrolled industrial wastes. Textile dyes that can
accumulate easily in their environments may show toxic effects. Pumice, accruing as a
result of volcanic events and durable against chemical factors, is a rock that has porous
structure. Pumices have a porous structure because of sudden cooling of the rock and
sudden leaving of gases a result of volcanic events. Thanks to these pores, pumices’ heat
and sound insulation are quite high. The most distinctive feature of pumice from other
rocks is that it has different colors and there is not crystal water in its porous structure.
Adsorption studies are applied with Van Pumice at pH = 6, the adsorption mechanism and
changing dye concentration. As result of these researches, it has been found out that there
are different adsorption movements at pH 6 between Neutral Red and Van Pumice. The
result of this study shows that the Pumice found in Lake Van gives a better fit for the
Langmuir Isotherm (model) and the amount of adsorption increases with the temperature.
We thereby conclude that the Pumice located in Lake Van is a recommended adsorbent for
filtering the used textile dye in aqueous medium.
Keywords: Textile dyes; adsorption; isotherm; Van pumice; thermodynamics.
Cite this: Kul A, Benek V, Selcuk A, Onursal N. Using Natural Stone Pumice in Van Region
on Adsorption of Some Textile Dyes. JOTCSA. 2017;4(2):49–60.
DOI: 10.18596/jotcsa.292662.
Corresponding author. E-mail:
Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
Pumice is a glassy, porous, and volcanic rock which occurs with the result of hollow,
spongy, volcanic rocks and is resistant against the physical and chemical effects (22). The
name "Ponza" or "Pomza" comes from Italian. There are different names in different
languages. In French it is called as "Ponce", in English, the middle ones are "Pumice",
naturally the tiny ones are "Pumicite", In German, the big ones are called as "Bimstein",
and tiny ones are called as "Bims". In Turkish, it is known as "Sünger taşı", "Köpük taşı",
"Topuktaşı" (6).
Because pumice it mostly porous, its heat and sound insulation is quite high. According to
Mohs scale, its hardness is 5-6. It does not contain crystal water. Its chemical component;
60%-70% SiO
, 13%-15% Al
, 1%-4% Fe
, 1%-2% CaO, 1%-2% MgO, 2%-5% Na
3%-4% K
O and it contains TiO
, SO
and Cl (13, 24).
During formation, because of sudden cooling and the gases inside the pumice's leaving, it
contains countless pores from macro scale to micro scale. Between pores are generally
(especially micro ones) disconnected hollows. Pores on pumice are mostly not connected
to each other. Each pore is isolated from each other with a glassy membrane. Because of
this feature, pumice is a good adsorbent (24, 3).
Pores on pumice are smaller than 1 mm. Pores are irregular, spherical, round and like
elongated pipes (11, 2).
The more pumice's piece size increases the more porous percent increases. Pumice’s
excess of porous percent and low specific weight ensure it to be used as a pouring material
for insulation areas. Also, thanks to the same features, it is highly porous; Pumice pieces
are not too much resistant. However, its durability is suitable for rock durability which was
used in carrier wall construction. (To 6 floors). Pumice is a good heat insulator. This feature
is increased with the event, which is called as “stack Porousness", in pumice block
manufacture that is especially struggled to reach. For the stack porousness, concrete is
prepared with a quite thin mortar and is ensured to cover only surround of pumice pieces
in a thin manner. The Pumice pores are not only helpful for insulation but also pumice
structure elements are highly adsorbent because it has features of removing capillary.
Pumice is grinded easily because of being a volcanic glass. Granulated Pumice was used
for similar goals both for the purpose of polishing and stoning and in match factories as an
ignition material and filling material, soap and cosmetic industry (21, 26).
Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
Because of porous being disconnected and having spaces, pumice is light, it can swim for
a long time and its permeability is low and its insulation (heat – sound insulation) is quite
high. Chemically, it contains about 75% silica. The amount of SiO
that rock contains,
provides an abrasive feature to the rock, therefore, it reveals a chemical status that can
easily erode steel. The compound of Al
provides a high resistant to fire and heat. Na
and K
O are known as minerals which give reactions in textile industry (9).
Economically functioned reserves are generally after tertiary reserves. World's pumice
reserves are more than 16 billion tonnes. USA has the biggest reserves while Turkey is the
second in terms of total pumice reserves. Important reserves of Turkey are in Tatvan and
Ahlat, Niğde-Nevşehir, Iğdır and Kars, Mollakasım (Van), Erciş (Van), Güdül (Ankara),
Doğubeyazıt (Ağrı) and Cumaovası' (İzmir).
Main manufacturers are Italy, Greece, Spain, Turkey, France, and Germany (26, 8).
Pumice rocks have recently gained updating as a popular industrial row material parallel
to various industries' establishment and development. Pumice was used in a large area
mainly as a light structure material, cement production, and filter material, acoustic and
polishing in industry. However, in our country, it is mostly used in bleaching jeans and in
production of briquette as a light structural material (24, 16).
Coloring of objects is expressed as "dyeing". Dye was used to protect the surface of objects
from external influences and to give a nice view. In speech, dye and dye material words
are used in the place of each other. These two words are not synonyms. Dyes are generally
inorganic. They are mixtures, which are mixed with a connector but dissolved in the
medium. They can be removed by scoping in large forms.
The materials which are used to color fabric and fiber are called as "dyeing material"
However, all colorful materials or color giving materials are not dye materials. Coloring,
applied by dye materials are not similar to coloring, applied by dye. Coloring is generally
applied with various dye methods in the form of solution or suspension.
All dye materials are organic compounds. The material to be dyed changes its structure by
chemical interaction with the dye. For this reason, the applicant cannot bring the material
back to the original by washing or cleaning. For that reason, the first dyes that are used
are mixture of metal–oxide, clay and some plant's sap (19).
Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
, Cr
, Pb
, HgS, graphite can be given as examples for the natural inorganic dyes.
Some of the dye materials are from natural sources, and some of them are synthetic.
Natural dye materials can be obtained generally from skin of animals and glands, root,
shell, seed, and fruit of plants and from microorganisms like yeast bacteria in the result of
simple chemical applications (4).
In the textile industry, one of the main problems is the removal of dyes and pigments from
the wastewater. It is known that most dyes are toxic, carcinogenic, and mutagenic to
aquatic organisms, so they have to be removed. Several methods, such as filtration,
coagulation, chemical oxidation, adsorption, etc., are used in order to remove dyes from
wastewater (18, 23, 9).
One of our aims is to evaluate pumice of the local resource, Van (Turkey), the original
material for production of adsorbent. Besides, it is known that pumice has pores. The
second purpose of this study is to investigate the adsorption isotherm, kinetics and the
thermodynamic parameters adsorption onto pumice derived from the Van region.
Chemical Materials: Experimental data are obtained from pH=6 solution. Different
concentrations of dye material's solution (50 ppm, 60 ppm, 70 ppm) are prepared for the
Adsorbents: Van Pumice was used as an adsorbent during experiment. Chemical
component of this pumice given in Table 1.
Table 1. Chemical components of Van pumice.
O Na
Loss of
Method: In this study, Van Pumice was used whose chemical analysis results are given.
Adsorption studies were applied with Van Pumice.
Pumices were applied the following operations detailed below:
a) Washing stage: Van Pumice which was grinded in the mill and which was filtered from
230 mesh sieve, was dried for 5.5 hours in the oven. 100 grams of Van Pumice was mixed
12 hours with 1.7 liter of pure water in the mixer. After mixing stage was finished, the
material was kept idle for 12 hours. It was observed that aqueous phase and solid phase
Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
were separated. Solid phase was separated by filtering. Solid phase was kept at ambient
conditions for 168 hours to dry. Dried Van pumice was filtered again with 230 mesh sieve.
It was placed in a desiccator until the time of experiment. Van Pumice was grinded in the
mill. After that, the size of the piece was minimized by filtrating 230 mesh sieves.
In the studies of adsorption balance, 1 gram of Pumice was treated 500 mL of dye material
solution. Dyeing material solutions were prepared in 50, 60, and 70 ppm concentrations,
were shaken with Van Pumice at different times (2, 5, 10, 15, 20, 25, 30, 40, 50, 60, 70,
80, 90, 100, 120, 150, and 180 minutes) in 25
C, 35
C, 45
C temperatures.
Dyeing material adsorption was examined depending on heat and time in the example of
Van Pumice. All of the adsorption measurement was applied with a spectrophotometer
(T80+ UV/VIS).
Freundlich Isotherm
The Freundlich isotherm assumes an empirical equation based on the heterogeneous
surface of adsorbent. The linear form of the Freundlich isotherm is expressed as (15):
= logK
+ nlogC
where K
is the Freundlich coefficient related to adsorption capacity, and n relates to
adsorption intensity. The values of the Freundlich constants were obtained from the linear
correlations between the values of log q
and log C
. In the Freundlich adsorption constant,
n should be greater than 1.
Langmuir Isotherm
In the solid/liquid adsorption process, adsorption of the solute is usually characterized by
either mass transfer (boundary layer diffusion) or intraparticle diffusion or even both (12).
The adsorption data of dye removal from pumice was analyzed by the Freundlich and
Langmuir isotherm models. The Langmuir isotherm model is valid for monolayer
adsorption. The linear equation of the Langmuir isotherm is (10):
where, C
is the equilibrium concentration of dye in the solution, q
amount of dye adsorbed
at equilibrium, q
Langmuir adsorption capacity, and b Langmuir constant.
The values of the Langmuir constants and coefficient determination R
are given in Table
2. The Langmuir adsorption capacity (q
) was found to be 27.3393, 26.5741 and 23.8115
mg/g at different temperatures (298, 308 and 318 K).
Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
Table 2. Equal values of Neutral Red adsorption on Langmuir and Freundlich equals from
different temperature.
T (K)
b (L/mg)
When R
values of both two adsorption isotherm models are taken into consideration, it
shows that the adsorption process has better compliance with the Langmuir adsorption
model than the Freundlich model. The Langmuir isotherm model is mostly valid for one
layer adsorption over specific number of similar surfaces. If the molecular interaction is
neglected, then it can be defined as adsorption behavior of a completely homogeneous
surface area. Despite the heterogeneity of the surface, Freundlich-type adsorption
isotherm displays the homogeneity of a Langmuir-type adsorption surface. The adsorption
of Langmuir isotherm increases linearly together with initial concentration of the adsorbate.
At maximum saturation point, the surface is coated with one layer and the amount of
adsorbate on the surface remains constant. Also, in this isotherm, the adsorption energy
is uniform. The speed of adsorption is directly proportional to the adsorbate concentration
and the active places over the surface. The speed of desorption is directly proportionate to
the amount of adsorbate adsorbed on the surface.
Thermodynamic Parameters
The thermodynamic parameters such as standard Gibbs fee energy (ΔG), entropy change
(ΔS) and enthalpy (ΔH) were calculated using following equations (17, 5):
∆ܩ = ∆ܪ − ܶ∆ܵ (5)
where K
is the equilibrium constant, C
initial concentration (mg/dm
), C
concentration, V volume (cm
), m of the pumice (g), T (Kelvin), and R gas constant (8.314
J/mol). The changes in enthalpy (ΔH) and entropy (ΔS) were determined from the slope
and intercept of the plots of lnK
versus 1/T. The Gibbs free energy (ΔG) was calculated
using Eq (5).
Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
Table 3. Thermodynamic parameters of Neutral Red adsorption on Van Pumice.
Temp (K) K
ΔG, kJ/mol ΔH, kJ/mol ΔS, kJmol
0,0013 0,0292
Concerning the adsorption of Neutral Red solutions onto the Pumice found in Lake Van,
thermodynamic parameters such as ΔG, ΔS and ΔH were determined at temperatures of
298, 308, and 318 K.
The negative value of Gibbs free energy (ΔG) shows that the adsorption process of Neutral
Red onto the Pumice located in Lake Van is spontaneous. The (ΔG) value tends to decrease
at increasing temperatures and thus demonstrates that this process can be carried out
much easier at high temperatures. The positive value of ΔS shows that, at the interface
between Neutral Red solution and the Pumice found in Lake Van, the sorption process
tends toward increasing disorder. The positive value of ΔH points out that the sorption
process is endothermic.
Adsorption Kinetics
The experimental data relating to adsorption of dye onto pumice was investigated using
the Lagergren pseudo-first and pseudo-second order equation (1, 7):
− ܳ
= ݈݋݃ܳ
ݐ (7)
where, q
is the amount of dye adsorbed at equilibrium (mg/g), q
amount of dye adsorbed
at various times, t time of adsorption duration, and k
is a rate constant of the equation
The k
and q
were calculated from the slope and intercept of the plots of log (q
versus t according to the pseudo-first-order model (Fig. 1) and t/q
versus t according to
the pseudo-second-order model (Fig. 2) as well as q
and k
from the slope and intercept
were calculated.
Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
Figure 1: Pseudo first order graph of Dye Adsorption on Van Pumice.
Figure 2: Pseudo second order graph of Dye Adsorption on Van Pumice
Table 4. Pseudo first order parameters of the dye.
T (K) k
(calc.) q
(exp.) R
Table 5. Pseudo second order parameters of the dye.
T (K) k
(calc.) q
(exp.) R
298 0,0250 18,2929 18,1510 0,9995
308 0,0115 22,5745 22,0815 0,9987
318 0,0388 22,5004 22,3605 0,9998
Regarding all the initial pumice amounts and temperature values of pumice, we concluded
that the kinetics of sorption onto the pumice has indicated a good compliance with the
quadratic form of the kinetic model. The correlation factor R
was found above 0,99.
Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
Considering all these results, we have concluded that the Pumice found in Lake Van is a
recommended adsorbent for the used dyestuff. We consider that the Pumice found in Lake
Van which is currently used in many fields of application, can also be used as an adsorbent.
In his Master of science thesis, “BIOSORPTION OF VICTORIA BLUE R (VBR) ONTO
his experimental data to the Langmuir isotherm model and obtained the resulting R2 values
at different temperatures, varying between 0,974 and 0,989. He later found out that these
high regression coefficients and its biosorption have indicated good compliance with the
Langmuir isotherm. Compliance with Langmuir isotherm showed out that the biosorption
occured on homogenous surfaces and the dye material VMR has coated the KIKU, forming
only one layer (20).
In his master of science thesis “Removal of Dye Materials from Aqueous solutions by
Adsorption on Coals and Cokes”, Kayacan has observed that both types of cokes comply
with the Freundlich isotherm and also with the Langmuir isotherms at the same time.
Besides, the MKP cokes rather comply with the Langmuir isotherm and the DB cokes
comply with Freundlich isotherm. It is thereby concluded that the MKP cokes have relatively
homogenous surfaces, but on the other hand, the DB cokes have relatively heterogeneous
surface. He found out that the b values of Langmuir’s isotherm of MKP cokes were relatively
high, thus he concluded that this is a clear proof of why these cokes are good adsorbents
(14). It is clear that both studies support our study.
In their studies, Turkmenoglu and her friends have used acidic Pumice found in Lake Van
in sizes of 0-2 mm, 2-4 mm and 4-8 mm respectively. They have found the physical
features of Pumice found in Lake Van as follows (25):
Van Pumice
2 mm
4 mm
8 mm
Specific Weight Factor
Water Absorption Rate (%)
Bulk Density (kg/m
The chemical and physical features of Pumice are some of those determining factors to find
out if it is a good adsorbent or not.
Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
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Kul, Benek, Selçuk, and Onursal, JOTCSA. 2017; 4(2): 525-536. RESEARCH ARTICLE
... Bağlantısız gözenekli yapısı sayesinde ses yalıtımının yanı sıra ısı altında da yüksek performans gösterir [7]. Pomza ayrıca kompozit [8], kimya [9,10], tekstil [11,12], tarım [13] ve yalıtım malzemesi [14,15] gibi pek çok alan ve sektörde yaygın olarak kullanılmaktadır. Pomza madenciliğinin gelişimi açısından, pomza rezervleri ve bunların farklı sektörlerde kullanımına yönelik çalışmaların ülke ekonomisine önemli katkılar sağlaması beklenmektedir [16]. ...
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Bu çalışmada, Nevşehir ilinde (Türkiye) bol miktarda bulunan bir hammadde olan mikronize pomzanın, üretim kapasitesi giderek artan vitrifiye ürünler için yapılan sır bileşimlerinde kullanılabilirliği araştırılmıştır. Bu amaçla, sır hammaddelerindeki kuvars, kaolin ve feldispat miktarları için Seger formülü kullanılarak mikronize pomza içeren farklı sırlar hazırlanmıştır. Sonuçlar bir vitrifiye firmasında (Turkuaz Seramik A.Ş., Kayseri) endüstriyel standart testler uygulanarak değerlendirilmiştir. Sırlar, ateş kili bünyelerine uygulanmış ve 1200-1250°C arasında değişen sıcaklıklarda endüstriyel bir pişirim rejiminde pişirilmiştir. Ayrıca, sır numunelerine tane boyutu analizi, fiziksel sır akış uzunluğu ve termal genleşme testi uygulanmıştır. Mikronize pomza içeren sırlı yüzeyler, renk parametreleri CIELab, Harkort testi ve lekelenmeye dayanıklılık testleri ile karakterize edildi. Taramalı elektron mikroskobu (SEM/EDS) ile birlikte X-ışını kırınımı (XRD) ile yapılan ölçüm, zirkon ve kuvars kristallerinin oluştuğunu göstermiştir. Mikronize pomza, homojen olarak dağılmış zirkon kristalleri oluşturan zirkon partikülleri ile reaksiyona girmesi için gerekli silikayı sağlamıştır. Zirkon kristalleri de beyazlığı yükseltmeyi başarmıştır. Seramik sağlık gereçleri sırlarında sürdürülebilir teknik özelliklerini bozmadan vitrifiye sır bileşimlerinde mikronize pomza kullanımının mümkün olduğu sonucuna varılmıştır.
... Turkey has a large portion of pumice reserves among other countries such as Italia, Spain, Mexico, Chile, USA, Iceland, Greece and Indonesia. Nevsehir, Kars, Ankara, Afyon, Izmir and Kayseri are the main areas where Turkish pumice deposits are found (Bolen 2008, Elmastas 2012, Kul et al. 2017, Yazicioglu et al. 2003. Because of pumice has a very porous structure, it is mainly used as light weight building materials. ...
... In literature when thermally dried S. cerevisiae was used as a biosorbent 95%, 96.16%, 61.82%, 96%, 97% dye removal percentage were achieved for Remazol Turkuaz, Navy Blue, Remazol Blue, Red 33:1 and Orange 1. When pumice stone was used as a biosorbent percentage dye removal was 38% for Neutral Red, 75% for AR14, 70% for AR18 [47][48][49]. When S. cerevisiae immobilized on sugarcane 31.34% ...
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In this study, Remazol Yellow (RR) removal was investigated by Saccharomyces cerevisiae immobilized on pumice stone. For immobilization process new technic was used and immobilization matrix HCl pretreated pumice stone was added to growth medium of microorganism. pH, initial biosorbent (Co) and dye concentration (Cb) effect on biosorption were optimized through the Response Surface Methodology (RSM) and second order quadratic model was used to describe the effects of parameters successfully. At optimum conditions pH 3, Cb 2.5 g/L, C0 400 ppm maximum dye removal was 99% and 140 mg/g capasity was catched. When pumice stone, HCl preated pumice stone and Saccaharomyces cerevisiae were used in biosorption experiments directly 44%, 69%, 75% dye removal was obtained respectively. 0.5 M NaOH (pH 13.69) and water (pH 8) were chosen as a desorption agent for the immobilised biosorbent. Desorption efficiency was found 21% with 0.5 M NaOH and 1.5% with water (pH 8). The characterization studies were performed by using Scanning Electron Microscope (SEM) and Fourier Transformer Infrared Spectroscopy (FTIR). The results indicate that immobilised biosorbent is a promising alternative for the biosorption of Remazol Yellow (RR) from aqueous solutions.
... Pomza daneleri, tek başına çok dayanıklı olmasa da, duvar imalatı vb. imalatlarda durabilitesi yüksek bir malzemedir [13] ...
... Pumices have a porous structure due to the result of volcanic events. Thanks to pores, pumices provide high insulation ( Kul et al., 2017). In literature, pumice was used as adsorbent for removing reactive azo dye from watery solutions ( Veliev et al., 2006). ...
Artan dünya nüfusu ve gelişen teknoloji ile birlikte, bilim insanları mevcut kaynaklara alternatif yollar aramaktadır. Özellikle, sağlık ve gıda endüstrisi üzerine yapılan çalışmalar oldukça dikkat çekicidir. Farmasötik, kozmetik, biyomedikal endüstrilerinde kullanılan ve insan sağlığına zarar veren kimyasalların yerine, biyouyumlu, toksik olmayan, anti-alerjik ve biyobozunur özelliklere sahip maddeler araştırılmaktadır. Doğada yaygın olarak bulunan materyaller kullanılarak, zararlı kimyasallara karşı çevre dostu ürünlerin üretimi gerçekleştirilmektedir. Dünyada en fazla miktarda bulunan polimerler sırasıyla selüloz ve kitindir. Selüloz ile kitin yapı olarak birbirlerine benzerlik göstermesine rağmen, selülozun içeriğinde bulunan C-2 pozisyonundaki hidroksi grubu yerine, kitinin yapısında asetamido gurubu bulunur. Bundan dolayı, kitinin yapısında azot oranı %5-8 arasında değişmektedir (Crognale et al., 2022). Bu iki makromoleküler biyopolimer, dünya üzerindeki bitkilerin ve hayvanların yapısında koruyucu etmen olarak bulunmaktadırlar (Canlı Taşar, 2015; Chatterjee et al., 2005; Honarkar & Barikani, 2009; Kaş, 1997).
Textile industry wastewater is considered one of the most terrible sources of pollution to our precious aquatic environment because it is mutagenic, carcinogenic, cytotoxic, and other genotoxic to natural compounds. This literature review collects and investigates the latest available research on photocatalytic wastewater or organic pollutant degradation using carbon-based materials in textile industrial wastewater treatment. Materials such as carbon have been used in several studies to enhance photocatalytic performance due to superior properties such as small particle size, high specific surface area-to-volume ratio, high reactivity, excellent chemistry, high thermal stability, wide availability, and catalytic potential on the nanoscale. Heterojunction formation is one of the most effective methods for increasing charge separation efficiency and reducing photogenerated electron–hole pair recombination. There are many ways to increase the photocatalytic performance for carbon-based material, such as heterojunction formation, using g-C3N4 or zinc oxide/carbon nanocomposite as a photocatalyst, surface modification to improve electron transport efficiency in semiconductor particles, using a green hydrothermal method to synthesize a hierarchy of graphene oxide/zinc nanocomposites, and more. Interestingly, the membrane separation technique explains the removal and recovery of synthetic colors from wastewater, which is a potential technical route. Functional composite membranes integrating photoelectrocatalysis and membrane filtration have been the subject of recent research. Finally, carbon-based materials are prospective to improve photocatalytic reaction due to their adsorption capability.
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Activated carbon (AC) was obtained from lignite of the local resource, Gölbaşı-Adıyaman (Turkey) by chemical activation. The Gölbaşı lignite was chosen as the precursor for its availability and low cost. The BET surface area of the activated carbon was found 921 m2/g. The AC was used as an adsorbent for Crystal Violet (CV) in aqueous solution. The adsorption properties of CV onto the activated carbon are discussed in terms of the adsorption isotherms (Langmuir and Freundlich) and the kinetic models (pseudo-first-order, pseudo-second-order and intraparticle diffusion model). It was shown that the experimental results best fitted by the Langmuir model, and the second-order kinetic equation. The thermodynamic parameters show that the adsorption process is endothermic. The experimental results point out that the obtained activated carbon is a viable candidate for sorbent removing CV from aqueous solutions.
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Acid activated mango leaf powder (MLP) was employed for removal of the rhodamine B (RB) dye from aqueous solution. Batch adsorption studies were carried out under varying conditions of dye concentration, adsorbent dose, particle size, contact time, pH, and temperature. Removal efficiency was 77% in 45 min with 6.0 pH, 25 g/L as dose, 250 mg/L RB concentration and 30°C temperature. The equilibrium data the best fitted with Langmuir model. The adsorption followed Lagergren pseudo-first order kinetics. The values of free energy change (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) indicated the process to be spontaneous. The diffusion studies indicated that adsorption initially takes place by external mass transfer and later by intraparticle diffusion. The results indicate that MLP is a good adsorbent for the removal of RB from wastewater.
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Adsorption isotherm of maxilon blue GRL on sepiolite was determined and correlated with common isotherm equations such as Langmuir and Freundlich models. It was found that the Langmuir model appears to fit the isotherm data better than the Freundlich model. Furthermore, adsorption kinetics experiments were carried out to remove the maxilon blue GRL from its aqueous solutions using sepiolite as an adsorbent. The remove rate of maxilon blue GRL by sepiolite was studied by varying parameters such as the contact time, stirring speed, initial dye concentration, ionic strength, pH and temperature. The kinetics experiments indicated that initial dye concentration, ionic strength, pH and temperature could affect the adsorption rate of maxilon blue GRL. Sorption data were fitted to pseudo-first-order, the Elvoich equation, pseudo-second-order, mass transfer and intra-particle diffusion models, and found that adsorption kinetics can be described according to the pseudo-second-order model, from which the rate constant and the adsorption capacity were determined. Rate constants under different conditions were also estimated. In addition, we found that the rate-limiting step was intra-particle diffusion. According to the change of intra-particle diffusion parameter, the adsorption processes could be divided into different stages. Thermodynamic activation parameters such as activation energy Ea, enthalpy ΔH*, entropy ΔS* and free energy ΔG* were determined. These parameters indicate that the adsorption has a low potential barrier corresponding to a physisorption; the adsorption reaction is not a spontaneous one; and the adsorption is physical in nature involving weak forces of attraction and is also endothermic.
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The removal of Zn(II) ions from aqueous solution was studied using natural and MnO(2) modified diatomite samples at different temperatures. The linear Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption equations were applied to describe the equilibrium isotherms. From the D-R model, the mean adsorption energy was calculated as >8 kJ mol(-1), indicating that the adsorption of Zn(II) onto diatomite and Mn-diatomite was physically carried out. In addition, the pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to determine the kinetic data. The experimental data were well fitted by the pseudo-second-order kinetic model. Thermodynamic parameters such as the enthalpy (ΔH(0)), Gibbs' free energy (ΔG(0)) and entropy (ΔS(0)) were calculated for natural and MnO(2) modified diatomite. These values showed that the adsorption of Zn(II) ions onto diatomite samples was controlled by a physical mechanism and occurred spontaneously.
The use of low-cost adsorbent has been investigated as a replacement for the current expensive methods of removing dyes from wastewater. As such, fly ash generated in National Thermal Power plant was collected and converted into a low-cost adsorbent. The prepared adsorbent was characterized and used for the removal of dyes from wastewater. Adsorption studies were carried out for different temperatures, particle sizes, pH's, and adsorbent doses. The adsorption of each dye was found to increase with increasing temperature, thereby indicating that the process is endothermic in nature. The removal of each dye was found to be inversely proportional to the size of the fly ash particles, as expected. Both the linear and nonlinear forms of the Langmuir and Freundlich models fitted the adsorption data. The results indicate that the Freundlich adsorption isotherm fitted the data better than the Langmuir adsorption isotherm. Further, the data were better correlated with the nonlinear than the linear form of this equation. Thermodynamic parameters such as the free energies, enthalpies, and entropies of adsorption of the dye−fly ash systems were also evaluated. The negative values of free energy indicate the feasibility and spontaneous nature of the process, and the positive heats of enthalpy suggest the endothermic nature of the process. The adsorptions of crystal violet and basic fuschin follow first-order rate kinetics. In comparison to other low-cost adsorbents, the sorption capacity of the material under investigation is found to be comparable to that of other commercially available adsorbents used for the removal of cationic dyes from wastewater.
Methylene blue was adsorbed on kaolin from a local deposit. The raw kaolin itself was a relatively good adsorbent. The adsorption capacity was improved by purification and by treatment with NaOH solution. Calcination of the kaolin reduced the adsorption capacity. The adsorption data could be fitted by the Freundlich and Langmuir equations. Also, the thermodynamic parameters such as ΔH0, ΔS0 and ΔG0 were determined.
The removal of BTEX (benzene, toluene, ethyl-benzene and m-,p-,o-xylenes), MTBE (methyl tertiary butyl ether) and TAME (tertiary amyl methyl ether) from aqueous solutions by raw, thermally, chemically and both chemically and thermally treated diatomite was studied, through batch adsorption experiments. In total, 14 different diatomite samples were created and tested. Selected physical characteristics of the adsorbents, such as specific surface area and pore volume distribution, were determined. Matrix and competitive adsorption effects were also explored. It was proved that the diatomite samples were effective in removing BTEX, MTBE and TAME from aqueous solutions, with the sample treated with HCl being the most effective, as far as its adsorption capacity and equilibrium time are concerned. Among the contaminants, BTEX appeared to have the strongest affinity, based on mass uptake by the diatomite samples. Matrix effects were proved to be strong, significantly decreasing the adsorption of the contaminants onto diatomite. The kinetics data proved a closer fit to the pseudo second order model, while the isotherm experimental data were a better fit to the Freundlich model. However, the latter produced values of the isotherm constant 1/n greater than one, indicating unfavorable adsorption.
The adsorbents of starch grafted p-tert-butyl-calix[4,6,8]arene-SGCn (SGC4, SGC6, SGC8) are prepared. The products are characterized by FTIR, elemental analysis, thermal gravimetric analysis and scanning electron microscope. Static adsorption behavior is studied by using SGC8 as adsorbent, butyl Rhodamine B (BRB) solution as simulation dye wastewater. The adsorption of BRB onto SGC8 fits the second order kinetic model and the apparent adsorption rate constant is 0.002 g mg(-1)min(-1) at 25 °C. The equilibrium adsorption data are interpreted using Langmuir and Freundlich models. The adsorption of BRB onto SGC8 is better represented by the Langmuir equation. The thermodynamic parameters for the adsorption reaction are calculated through van't Hoff analysis. The adsorbent may be easily regenerated by using ethanol solution as desorption agent to extract dye from SGC8. The rate of desorption of BRB is dependent on the concentration of ethanol and the temperature. SGC8 exhibits excellent adsorption and desorption properties toward dye molecule. The new-style adsorbent of SGC8 is regarded as a potential adsorbent to deal with dye or organic wastewater.
Adsorption of Crystal violet, a basic dye onto phosphoric and sulphuric acid activated carbons (PAAC and SAAC), prepared from male flowers coconut tree has been investigated. Equilibrium data were successfully applied to study the kinetics and mechanism of adsorption of dye onto both the carbons. The kinetics of adsorption was found to be pseudo second order with regard to intraparticle diffusion. The pseudo second order is further supported by the Elovich model, which in turn intensifies the fact of chemisorption of dye onto both the carbons. Quantitative removal of dye at higher initial pH of dye solution reveals the basic nature of the Crystal violet and acidic nature of the activated carbons. Influence of temperature on the removal of dye from aqueous solution shows the feasibility of adsorption and its endothermic nature. Mass transfer studies were also carried out. The adsorption capacities of both the carbons were found to be 60.42 and 85.84 mg/g for PAAC and SAAC, respectively. Langmuir's isotherm data were used to design single-stage batch adsorption model.
Investigation of the Technological Properties of the Izmir-Menderes Pumice Ore
  • E Aksay
Aksay E. Investigation of the Technological Properties of the Izmir-Menderes Pumice Ore. [İzmir]: Dokuz Eylül University; 2005.