Effect of pH on Biosorption of Basic Dye Malachite Green bt Algae

<strong>Effect</strong> <strong>of</strong> <strong>pH</strong> on Biosorption <strong>of</strong> Basic Dye Malachite Green
bt Algae
Kawin Pansamrit and Suneerat Ruangsomboon *
1 Program in Fisheries Science, Division <strong>of</strong> Animal Production Technology and Fisheries,
Faculty <strong>of</strong> Agricultural Technology, King Mongkut’s Institute <strong>of</strong> Technology
Ladkrabang, Bangkok, Thailand
Abstract
The optimal <strong>pH</strong> for malachite green (basic dye OT 70701 A) removal from solution by 13 genus
<strong>of</strong> algae (Acanthophora sp., Gracilaria sp., Solieria sp., Padina sp., Turbinaria sp., Dictyota sp.,
Sargassum sp., Caulerpa lentillifera, Caulerpa sertularioides., Cladophora sp., Ulva rigida, Ulva
intestinalis, Chaetomorpha sp., Spirulina platensis and Phormidium angustissimum) was studied.
Dried algal cells were added in malachite green solution with initial concentration <strong>of</strong> 5 mg/L at
initial <strong>pH</strong> 2, 3, 4, 5, 6, 7 and 8 and shaking for 3 h. The optimum <strong>pH</strong> for malachite green sorption
by Solieria sp. was 5, S. platensis., U. intestinalis and U. rigida was 7 and other genus <strong>of</strong> algae
was 6. Padina sp. showed significantly higher biosorption ability, 4.28±0.03 mg/g dry wt., than
other algae (p

eported that <strong>pH</strong> not only affects the dye biosorption capacity but also the solubility <strong>of</strong> dyes [7]
and surface binding-sites <strong>of</strong> cell wall <strong>of</strong> algae contains several charged group [8]. Therefore <strong>pH</strong> is
an important factor in dye removal.
The aim <strong>of</strong> the present study was to evaluate the effect <strong>of</strong> <strong>pH</strong> on malachite green removal
from aqueous solution by algae and to evaluate the ability and potential use <strong>of</strong> algae to remove
malachite green.
2. Materials and Methods
2.1 Macroalgae and Microalgae (cyanobacteria)
Marine macroalgae were collected from natural and aquatic farm. Caulerpa lentillifera, Caulerpa
sertularioides and Acanthophora sp. were collected from Banjong Farm, Chachoengsao province
on May. Cladophora sp., Chaetomorpha sp., Ulva rigida and Ulva intestinalis were collected from
Trat coastal aquaculture station, Trat province on May. Sargassum sp., Dictyota sp. and
Turbinaria sp. were collected from Chonburi province on March. Padina sp. were collected from
Trat province. Gracilaria sp. and Solieria sp. were collected from Samutsakron province on April.
The algae were washed with water to remove the surface-adhered particles and dried with sun
light then powdered to study the malachite green removal ability.
Cyanobacteria (Spirulina platensis and Phormidium angustissimum) were obtained from
the King Mongkut’s Institute <strong>of</strong> Technology Ladkrabang, Faculty <strong>of</strong> Agricultural Technology,
Program in Fisheries Science, Division <strong>of</strong> Animal Production Technology and Fisheries (KMITL,
Bangkok, Thailand). S. platensis was cultured in Zarrouk’s medium and P. angustissimum was
cultured in BG-11 medium under continuous illumination <strong>of</strong> 30 µmol photons/m 2 /s at 28±2ºC. The
cyanobacterial cells at 2 weeks period <strong>of</strong> culture (late exponential phase) were harvested by
filtration and dried at 60 ºC. and powdered before studying the malachite green removal ability.
2.2 Basic dye removal ability
To study the basic dye removal ability (qeq): 0.01 g (dry weight) <strong>of</strong> algal cells was added in 10 mL
solution <strong>of</strong> malachite green at concentrations <strong>of</strong> 5 mg/L at <strong>pH</strong> 2, 3, 4, 5, 6, 7 and 8 in a 125-mL
Erlenmeyer flask. The flasks were shaken at 120 rpm on a shaker at 25 °C for 180 min. Then algal
cells were separated by filtration. Malachite green remained in solution was analyzed. The values
<strong>of</strong> qeq were calculated using the mass balance equation: qeq = V(Ci-Ceq)/M where Ci is the initial
dye concentration (mg/L), Ceq is the final concentration <strong>of</strong> dye solution (mg/L), V is the volume <strong>of</strong>
solution (mL), and M is algal dry weight (g).
2.3 Basic dye and Statistical analysis
Basic dye (malachite green) concentration was analyzed by a spectrophotometer (Becthai,
Thailand) at wavelength 618 nm. All experiments were conducted in three replicates. Significant
differences were determined using analysis <strong>of</strong> variance (ANOVA) with 95% confidence
(probability limit <strong>of</strong> p

Solieria sp. (0.50±0.03 mg/g dry wt.) and Chaetomorpha sp. (0.61±0.02 mg/g dry wt.) showed
significantly lower dye removal ability than other algae (p0.05)
The same capital letter in each column mean absence <strong>of</strong> statistical differences (p>0.05)
2.29±0.03 eF
3.75±0.04 hE
0.49±0.02 aD
4.28±0.03 kF
4.05±0.03 jE
3.81±0.01 hiF
4.10±0.02 jE
3.17±0.03 gD
2.32±0.02 eE
3.90±0.04 iE
0.72±0.07 bcD
0.78±0.01 cE
0.61±0.02 abD
2.00±0.14 dC
2.55±0.04 fF
2.10±0.01 cE
3.32±0.01 fD
0.47±0.01 aCD
3.43±0.02 fghD
3.41±0.02 fgD
3.48±0.02 ghiE
3.60±0.01 iD
2.68±0.01 eC
2.23±0.00 cD
3.58±0.00 hiD
0.72±0.02 bC
0.82±0.01 bC
0.52±0.01 aC
2.44±0.10 dD
2.21±0.01 cE
2.08±0.02 cE
3.25±0.01 gD
0.45±0.01 aCD
3.57±0.02 hiE
3.49±0.02 hiD
3.48±0.01 hE
3.63±0.01 iD
2.76±0.02 fC
2.18±0.03 cdCD
3.53±0.05 hiD
0.71±0.01 bC
0.75±0.03 bC
0.54±0.02 aC
2.41±0.16 eD
2.23±0.02 dE
At a higher <strong>pH</strong> above this zero point charge, the surface <strong>of</strong> biomass gets negatively
charged, which enhances the positively charged <strong>of</strong> dye cations through electrostatic force <strong>of</strong>
attraction and at lower <strong>pH</strong>, the surface charge may get positively charged (i.e. protonation <strong>of</strong> the
cell wall), thus making (H+) ions compete effectively with dye cations toward actives sorption
sites causing a decrease in the amount <strong>of</strong> adsorbed dye [1, 4, 8]. Many studies have been done on
effect <strong>of</strong> initial <strong>pH</strong> solution on the color removal effciency <strong>of</strong> malachite green solution by green
algae. Cosmarium sp. Malachite green removed ability was analyzed over a <strong>pH</strong> range from 2.0 to
11.0. It shown that an increase in <strong>pH</strong> from 4.0 to 6.0 leads to a threefold increase in decolorization

ate, which is reached the maximum value <strong>of</strong> 92.4% at the <strong>pH</strong> <strong>of</strong> 9.0 and the color removal
effciency from 26.3% to 68.4% for an increase in <strong>pH</strong> from 3.0 to 4.0 [4].
d
g
a
i
h
g
Figure 1. Basic dye removal ability (qeq, mg/g dry wt.) <strong>of</strong> algae with optimal <strong>pH</strong> (initial dye
concentration <strong>of</strong> 5 mg/l). The same small letter mean absence <strong>of</strong> statistical differences (p>0.05)
The influence <strong>of</strong> initial dye solution <strong>pH</strong> <strong>of</strong> malachite green removal by a fresh water
algae Pithophora sp. at different solution <strong>pH</strong> ranging from 2 to 7 at initial malachite green
concentration 50 mg/L was studied. It was shown that maximum <strong>of</strong> 64.4 mg/g <strong>of</strong> dye was
adsorbed at a <strong>pH</strong> <strong>of</strong> 6 [1]. The optimum initial <strong>pH</strong> for malachite green removal by brown algae
Turbinaria conoides biomass at initial dye concentration 100 mg/L was found to be 8.0 and
showed maximum adsorption capacity 66.6 mg/g [9].
The effect <strong>of</strong> <strong>pH</strong> on removal <strong>of</strong> basic dye, methylene blue using green alga Enteromorpha
spp. was investigated for values between 2 and 10. The sorption capacity was minimum at <strong>pH</strong> 2
(40.21 mg/g) and increased up to <strong>pH</strong> 6, then remained nearly constant (70.35 mg/g) over the initial
<strong>pH</strong> ranges <strong>of</strong> 6–10 [10]. The percentage sorption <strong>of</strong> methylene blue by giant duckweed Spirodela
polyrrhiza at initial <strong>pH</strong> between 2-11 was reported. S. polyrrhiza showed minimum sorption at the
initial <strong>pH</strong> 2, and the percentage sorption <strong>of</strong> methylene blue was not significantly altered (p>0.05)
when the initial <strong>pH</strong> was increased from 3 to 11. S. polyrrhiza showed maximum adsorption
capacity between 126.58-129.87 mg/g [11].
4. Conclusions
The optimal <strong>pH</strong> for malachite green (basic dye OT 70701 A) removal by Soliera sp. was 5,
Spirulina platensis, Ulva intestinalis and Ulva. rigida was 7 and Acanthophora sp., Gracilaria sp.,
Padina sp., Turbinaria sp., Dictyota sp., Sargassum sp., Caulerpa lentilifera, Caulerpa
The 8 th International Symposium on Biocontrol and Biotechnology 223
h
d
f
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bc c
ab
de e

sertularioides, Cladophora sp., Chaetomorpha sp. and Phormidium angustissimum was 6. Padina
sp. showed the highest malachite green removal ability.
5. Acknowledgements
This study was grants by the National Research Council <strong>of</strong> Thailand.
References
[1] Kumar, K.V., Ramamurthi, V. and Sivanesan S., 2006. Biosorption <strong>of</strong> malachite green, a
cationic dye onto Pithophora sp., a fresh water algae. Dyes and Pigments, 69, 102-107.
[2] Sivaraj, R., Namasivayam, C. and Kadirvelu, K., 2001. Orange peel as an adsorbent in the
removal <strong>of</strong> acid violet 17 (acid ye) from aqueous solutions, Waste Management, 21, 105-10.
[3] Bekci, Z., Seki, Y. and Cavasb, L., 2009. Removal <strong>of</strong> malachite green by using an invasive
marine alga Caulerpa racemosa var. cylindracea. Journal <strong>of</strong> Hazardous Materials, 161,
1454–1460.
[4] Daneshvar, N., Ayazloo M., Khataee, A.R. and Pourhassan, M., 2007. Biological
decolorization <strong>of</strong> dye solution containing Malachite Green by microalgae Cosmarium sp.
Bioresource Technology, 98, 1176–1182.
[5] Marungrueng, K. and Pavasant, P., 2007. High performance biosorpbent (Caulerpa
lentillifera) for basic dye removal. Bioresource Technology, 98, 1567-1572.
[6] Wafaa, M., El-Rahim, A. and El-Ardy, O.A.M., 2008. Hassan Moawad, Aeration as a factor
in textile dye bioremoval by Aspergillus niger. African Journal <strong>of</strong> Biochemistry Research,
2(1), 30–39.
[7] Fu, Y.Z. and Viraraghavan, T., 2001. Removal <strong>of</strong> CI Acid Blue 29 from an aqueous
solution by Aspergillus niger. American Association <strong>of</strong> Textile Chemists and Colorists
Review, 1(1), 36–40.
[8] Tsai W.T. and Chen H.R., 2010. Removal <strong>of</strong> malachite green from aqueous solution using
low-cost chlorella-based biomass. Journal <strong>of</strong> Hazardous Materials, 175, 844–849.
[9] Kannan, R.R., Rajasimman, M., Rajamohan, N. and Siaprakash, B., 2010. Brown marine
algae Turbinaria conoides as biosorbent for Malachite green removal: Equilibrium and
kinetic modeling. Frontiers <strong>of</strong> Environmental Science and Engineering in China, 4(1), 116–
122.
[10] Ncibi, M.C., Hamissa, A.M.B., Fathallah, A., Kortas, M.H., Baklouti, T., Mahjoub, B. and
Seffen, M., 2009. Biosorptive uptake <strong>of</strong> methylene blue using Mediterranean green alga
Enteromorpha spp. Journal <strong>of</strong> Hazardous Materials, 170, 1050–1055.
[11] Waranusantigul, P., Pokethitiyooka, P., Kruatrachuea, M. and Upathama, E.S., 2003.
Kinetics <strong>of</strong> basic dye (methylene blue) biosorption by giant duckweed (Spirodela
polyrrhiza). Environmental Pollution, 125, 385–392.
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