Adsorption of methylene blue from aqueous solution using untreated and treated (Metroxylon spp.) waste adsorbent: equilibrium and kinetics studies
Int J Ind Chem
DOI 10.1007/s40090-016-0085-9
RESEARCH
Adsorption of methylene blue from aqueous solution using
untreated and treated (Metroxylon spp.) waste adsorbent:
equilibrium and kinetics studies
Jeminat O. Amode1 • Jose H. Santos1 • Zahangir Md. Alam2 • Aminul H. Mirza1 •
Chan C. Mei1
Received: 5 October 2015 / Accepted: 17 May 2016
Ó The Author(s) 2016. This article is published with open access at Springerlink.com
Abstract
Background (Metroxylon spp.) waste is an inexpensive
and abundantly available material with the characteristics
of a good adsorbent for treating dye from wastewater. We
studied the effectiveness of alkali and acid modification in
enhancing the adsorption capacity of sago waste. The
untreated and treated adsorbent was characterized by FTIR,
elemental analysis and BET surface area. The capacity of
each adsorbent to adsorb MB was evaluated at different pH
values, adsorbent dosage and initial dye concentrations and
contact time.
Results According to the results obtained, alkali treatment
more than doubled the sorption capacity of sago waste by
increasing the porosity, surface area and number of adsorption sites. The alkali-treated material also adsorbed significantly more than many known biosorbents. The effects of the
initial concentration of methylene blue, solution pH and
adsorbent dosage on methylene blue removal are reported.
Equilibrium data were best represented by the Langmuir
isotherm model with adsorption capacities of 83.5, 212.8 and
36.82 mg/g for untreated, potassium hydroxide-treated and
phosphoric acid-treated sago wastes, respectively. The
kinetics of adsorption were best described by a pseudo-second-order model (R2 = 0.999).
Conclusions The alkali treatment of sago waste demonstrates the use of a low-cost agricultural waste and a simple
& Jose H. Santos
1
Faculty of Science, Universiti Brunei Darussalam, Jalan
Tungku Link, Gadong 1410, Negara Brunei Darussalam
2
Bioenvironmental Engineering Research Unit (BERU),
Faculty of Engineering, International Islamic University
Malaysia (IIUM), Kuala Lumpur, Malaysia
modification process to produce an effective adsorbent for
removing cationic dye from wastewater.
Keywords (Metroxylon spp.) waste Methylene blue
Low-cost adsorbent Adsorption Alkali modification
Water treatment
Introduction
Wastewater effluents from many industries, including paper,
leather, textiles, rubber, plastics, printing, cosmetics, pharmaceuticals and food, contain several kinds of synthetic
dyestuffs [1]. Dye-bearing wastewaters exhibit high chemical and biochemical oxygen demands [2]. The presence of
even very low concentrations in discharge effluents to the
environment is worrying for both toxicological and esthetic
reasons [3, 4]. To reduce the negative effects of dye-contaminated wastewater on humans and the environment, the
wastewater must be treated carefully before discharge into
main streams [5]. Various physical, chemical and biological
methods, including adsorption, biosorption coagulation and
flocculation, advanced oxidation, ozonation, membrane filtration and liquid–liquid extraction, have been widely used
for the treatment of dye-bearing wastewater [2, 6–8].
Adsorption is a very effective separation technique and is
considered to be superior to other techniques for water
treatment in terms of initial cost, simplicity of design, ease of
operation and resilience to toxic substances [9, 10]. Although
adsorption technologies are well established, a significant
limitation is the cost of adsorbent materials. This has motivated the search for low-cost and renewable materials for use
as sorbents and has led to a growing interest in the use of
nonconventional and locally available materials such as
natural materials and agricultural wastes.
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Int J Ind Chem
Recently, a large number of low-cost adsorbents have
been utilized to develop cheaper and effective adsorbents
to remove dyes from wastewater, including cucumber peels
[11], meranti sawdust [12], bagasse [13], durian leaf
powder [14], watermelon seed hulls [11], grape pulp [15],
chitosan [16, 17], kenaf core fibers [18], etc. The reported
results showed that most of these readily available bioadsorbents possess high efficiency in removing dyes from
aqueous solutions [16, 19]. These lignocellulosic byproducts possess various advantages, such as being ecofriendly, renewable, less expensive and abundantly available, as compared to commercial adsorbents [18, 20].
Studies have also shown that chemical modification of
agricultural by-products significantly enhances their ionbinding properties, thereby providing greater flexibility in
their applications to a wide range of dyes [21–24]. However, while agricultural by-products are often presented as
low-cost adsorbents, their availability is often region specific. With the majority of costs in using biosorbents being
associated with the transportation of materials [25], their
viability may be limited to the region of origin. Agricultural waste is a low-cost and abundantly available material
in Brunei Darussalam among other areas in the Asia–
Pacific region. (Metroxylon spp.) waste also known as sago
hampas is a by-product of starch extraction from Metroxylon sagu (sago palm). Sago palm is becoming an important socioeconomic crop in countries such as Papua New
Guinea, Indonesia, Malaysia, Thailand and the Philippines
[26]. This biomass has good chemical stability, high
mechanical strength and a granular structure, making it a
good adsorbent material for treating dye from wastewater.
In the present study, agricultural sago waste was treated
with alkaline and acid for the removal of methylene blue
from aqueous solutions. The enhancement of unmodified
Metroxylon spp. waste by alkali and acid treatment has
been investigated here toward the development of a dyeremoving adsorbent that is high in adsorption capacity,
cost-effective and requires only simple processing. Batch
studies were performed to evaluate the effects of various
parameters such as pH, initial dye concentration and
adsorbent dosage on the removal of a basic dye from an
aqueous solution. The textural and physicochemical properties, adsorption isotherms and kinetic parameters have
also been determined and discussed.
Fig. 1 The structure of methylene blue chloride salt
sodium chloride, sodium hydroxide, hydrochloric acid and
methylene blue (MB). Methylene blue was chosen in this
study because of its known strong adsorption onto solids
and its recognized usefulness in characterizing adsorptive
material [27]. Methylene blue has a molecular weight of
319.85 g mol-1, which corresponds to the heterocyclic aromatic chemical compound with the molecular
formula C16H18N3SCl. Methylene blue has a net positive
charge and the structure of this dye is shown in Fig. 1.
Stock solutions were prepared by dissolving an accurately weighed 1.000 ± 0.0005 g of dye in 1 L of distilled
water. Stock solutions were covered with aluminum foil
and stored in a (...truncated)
