close

Вход

Забыли?

вход по аккаунту

?

Biosorption of heavy metal using brown seaweed in a regenerable continuous column.

код для вставкиСкачать
ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING
Asia-Pac. J. Chem. Eng. 2008; 3: 572–578
Published online in Wiley InterScience
(www.interscience.wiley.com) DOI:10.1002/apj.202
Research Article
Biosorption of heavy metal using brown seaweed in a
regenerable continuous column
N. Rajamohan* and B. Sivaprakash
Department of Chemical Engineering, Environmental Engineering Laboratory, Annamalai University, Annamalai Nagar, Tamilnadu, India
Received 10 March 2008; Revised 23 July 2008; Accepted 23 July 2008
ABSTRACT: This paper deals with the experimental investigation on removal of cadmium [Cd(II)] ions from an
aqueous solution using a marine alga, Sargassum tenerrimum, in a fixed-bed column. The effects of the inlet flow rate
and the sorbent bed height on the biosorption of Cd(II) ions were studied. The dynamics of column biosorption was
modeled by the bed depth service time (BDST) model and the Thomas model. The BDST model was used to study the
dynamic sorption behavior at different bed heights, whereas the Thomas model was used to fit the column biosorption
data at different flow rates. The uptake capacity and the breakthrough time increase with an increase in the bed height.
The sorption capacities of the bed per unit volume and the rate constant Ka were found to be 3819.42 mg/l and
0.0353 mg/h respectively. In flow rate experiments, the results confirmed that the metal uptake capacity and the metal
removal efficiency of S. tenerrimum decreased with increasing flow rate. The Thomas model was used to fit the column
biosorption data at different flow rates and model constants were evaluated. After five sorption–desorption cycles, the
selected marine alga exhibited a high cadmium uptake of 63.43 mg/g.  2008 Curtin University of Technology and
John Wiley & Sons, Ltd.
KEYWORDS: biosorption; Sargassum tenerrimum; bed depth service time
INTRODUCTION
Water pollution owing to the release of heavy metals
from industries has become a major issue throughout the
world. If these discharges are emitted without treatment,
they may have an adverse effect on the environment
and, consequently, on human health. In recent years,
one of the main goals regarding heavy metal removal
from wastewater consists in the reduction of these pollutants at very low levels.
Cadmium is one of the toxic heavy metals found
in the wastewater discharges from the electroplating
industry, the manufacture of nickel–cadmium batteries, fertilizers, pesticides, pigments and dyes and textile operations.[1,2] Several toxic but nonfatal symptoms
are reported in the cadmium concentration range of
10–326 mg Cd 2+/l. The disorders caused by cadmium on human beings are renal dysfunction and
hypertension.[3,4]
Conventional methods such as precipitation or ion
exchange are not useful in this case or when metals
are present in the concentration range of 1–100 mg.[5]
*Correspondence to: N. Rajamohan, Department of Chemical Engineering, Environmental Engineering Laboratory, Annamalai University, Annamalai Nagar 608002, Tamilnadu, India. E-mail: rajmohan tech@yahoo.com
 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
The application of microorganism as biosorbents for
removal of heavy metals offers a potential alternative to
the existing methods. Many aquatic organisms such as
algae can adsorb heavy metals from their surroundings.
Metal ion binding to nonliving cells occurs rapidly by
cell surface adsorption and is called biosorption. The
use of dead biomass is more favorable for water as
dead organisms are not affected by toxic contaminants.
The kinetics of metal uptake, thought to be the physical
adsorption at the cell surface, is very rapid and occurs
within a short time after the biomass–metal contact.
The polysaccharides of the algal cell wall could provide amino and carboxyl groups along with sulfate. The
amino groups on the proteins of the cell wall and the
nitrogen and oxygen of the peptide bond could also
be available for binding metallic ions. Such bond formation could be accompanied by the displacement of
protons dependent in part on the extent of protonation as
determined by pH. Metallic ions could also be bounded
electrostatically to unprotonated carboxyl oxygen and
sulfate.[6,7]
Although many types of reactors such as batch reactor, continuous-stirred tank reactor, fluidized bed and
moving bed columns can be used, adsorption separation
techniques are almost carried out in packed columns.
Packed bed adsorption has a number of advantages such
as its simplicity, high operation yield, easy scale-up
Asia-Pacific Journal of Chemical Engineering
procedure and high degrees of purification in a single
step.[8] Packed bed columns with continuous flow allow
the regenerating cycles operation. The sorbent can be
regenerated using an appropriate eluent solution. The
regeneration process liberates small volumes of concentrated metal solutions, which are more appropriate
for conventional recovery methods.[9]
The present study was carried out to evaluate the performance of Sargassum tenerrimum, a marine brown
alga, for the Cd (II) removal in an up-flow packed column reactor. The effects of design parameters such as
bed height and flow rate on the shape of the breakthrough curves were investigated. The dynamics of
biosorption process was modeled by the bed depth service time (BDST) model and the Thomas model. This
study forms a part of the overall experimental investigations to develop a biosorption process to remove
cadmium ions from waste water.
MATERIALS AND METHODS
BIOSORPTION OF HEAVY METAL USING BROWN SEAWEED
to get the desired flow rates. Cadmium solutions of relatively lower concentrations are used to obtain a gentle
breakthrough curve as industrial effluents possess cadmium concentration in this range. After biosorption,
the pH of the effluent was adjusted to a value below
2 and the residual concentration of metal ions were
analyzed by flame atomic absorption spectrophotometer
(Perkin Elmer, model 373) and the column was operated till the effluent metal concentration reached a value
of 99.5 mg/l or higher. The biomass loaded with cadmium ions was regenerated with 0.1 M HCl (flow rate
5 ml/min) after exhaustion. The bed was washed with
distilled water after elution to stabilize the wash effluent
to a pH of 7. The sorption and desorption studies were
conducted again by feeding the cadmium solution; these
cycle studies were carried out five times and the sorption capacity was evaluated. The biomass was washed
with distilled water and dried at 60 ◦ C to determine the
loss in weight after five cycles. All the column experiments were carried out in duplicate; the deviations were
within 5%.
Biomass pretreatment
Modeling of breakthrough curves
The marine alga, S. tenerrimum, was collected in
Mandapam (Tamilnadu, India) and then sun dried.
It was then grounded to an average particle size of
0.76 mm. The sieved biomass was soaked in 0.1 M
HCl for 4 h in order to protonate it. The alga was then
washed in distilled water and dried at 60 ◦ C overnight.
A weight loss of approximately 15% was observed.
Continuous flow studies in a packed bed
column
The continuous flow sorption experiments were conducted in an acrylic column of internal diameter 3 cm
and a height of 40 cm. To enable a uniform inlet flow
of the solution into the column, glass beads of 1.5 mm
diameter were placed to attain a height of 2 cm. An
adjustable plunger was held in position at the top of
the column with a 0.5-mm stainless sieve. A 0.5-mm
stainless sieve followed by glass wool was provided at
the bottom of the column to support the packing.
Experimental procedure
A stock solution of cadmium was prepared by dissolving AR grade of Cd(NO3) in distilled water. A known
quantity of biomass was placed in the column to yield
the desired sorbent bed height. Cadmium nitrate solutions of initial concentration 100 mg/l at pH 6 (based
on preliminary studies) were fed upward inside the column by a peristaltic pump (Miclins India, model pp60)
 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
The shape of the breakthrough curves was found to be
affected by the fluid velocity, concentration of solute in
the feed and the bed height. The breakpoint could be
sharply defined in some cases and poorly in others.[10]
Breakthrough curves with steep slopes were obtained
for systems that exhibit high film transfer coefficients,
high internal diffusion coefficients or flat adsorption
isotherm.[11] The column data can be modeled by establishing a term named service time, which is defined as
the time required for the effluent cadmium concentration
to reach 1 mg/l. The fundamental equation describing
o
the relationship between C
Cb and t in a continuous system was established for the adsorption of sorbate on a
sorbent; this is known as the BDST model, which is
expressed as follows[12] :
t=
No Z
1
Co
−
ln(
− 1)
Co v
Ka Co
Cb
(1)
where Cb is the breakthrough metal ion concentration
(mg/l),
Co is the initial metal ion concentration (mg/l)
Z is the bed height (cm),
No is the sorption capacity of bed (mg/l),
v is the linear velocity (cm/h) and
Ka is the rate constant (l/mg h).
The important feature in the design of the fixed-bed
adsorption column is the prediction of the concentration
time profile or the breakthrough curve for the effluent
and a mathematical model to fit them. One of the
simple and generally used models[13] reported by many
Asia-Pac. J. Chem. Eng. 2008; 3: 572–578
DOI: 10.1002/apj
573
N. RAJAMOHAN AND B. SIVAPRAKASH
Asia-Pacific Journal of Chemical Engineering
researchers is the famous Thomas model, which is
expressed in linear form as
ln
Co
kTh Qo M
kTh Co V
−1=
−
C
F
F
(2)
where C is the effluent cadmium concentration (mg/l),
kTh is the Thomas model constant (l/mg h), Qo is the
maximum concentration of solute in the solid phase
(mg/g), F is the flow rate (ml/min), M is the sorbent
mass (g) and V is the throughput volume (l).
The amount of metal adsorbed by the biomass (mad ) is
obtained by multiplying the area above the breakthrough
curve and the flow rate. The amount of cadmium
adsorbed by algae was calculated from the differences
between the amount added to the biomass and the
cadmium content after adsorption using the following
equation.[13]
(Co − C )
(3)
Q =V
M
The mass transfer zone (t) is evaluated as the
difference between the breakthrough time (tb , time
at which the cadmium concentration in the effluent
reached 1 mg/l) and the exhaustion time (te , time
at which the cadmium concentration in the effluent
exceeded 99.5 mg/l)
t = te − tb
(4)
The critical bed height, which is also termed as the
height of the mass transfer zone (Zm ), is related to
bed height, breakthrough and exhaustion times and is
determined using[14]
Zm = Z (1(−(tb − te ))
mtotal = Co Fte /1000
η (%) = mad × 100/mtotal
Effect of bed height on the performance of
breakthrough
The adsorption of metal in the packed bed column is
greatly influenced by the amount of biosorbent used.
The study was conducted for three different bed heights:
15, 20 and 25 cm using 12.13, 14.82 and 19.15 g
of biomass respectively. A flow rate of 5 ml/min
of cadmium solution with an initial concentration of
100 mg/l was fixed as the feed condition for the
column studies. Figure 1 represents the breakthrough
curves for the adsorption of cadmium by S. tenerrimum
obtained for the various bed heights, viz., 15, 20 and
25 cm. It can be seen that the breakthrough time and
exhaustion time increased with increasing bed height.
The uptake capacity of cadmium and the breakthrough
time increases with increase in bed height, which leads
to an increase in the surface area of the adsorbent.[15]
It was found that 68.23, 68.86 and 69.37 mg/g of
cadmium uptake were obtained by the biomass for
15, 20 and 25 cm of bed heights respectively, which
correspond to total cadmium removal percentages of
56.96, 60.82 and 60.47% respectively, showing an
increasing trend with respect to the bed height (Table 1).
The BDST model provides a simple and comprehensive approach for evaluating the column sorption test.
Figure 2 indicates the linearity between the service time
and bed height with a correlation coefficient of 1 for a
flow rate of 5 ml/min, and hence the BDST model holds
good for the present system. The initial concentration Co
and the linear velocity v were held constant during the
column operation. The sorption capacity of the bed per
unit bed volume No and the rate constant Ka were computed from the slope and intercept of BDST plot; these
(5)
The other parameters involved in the analysis of
column studies are the effluent volume (Veff ), quantity
of cadmium ions sent to the column (mtotal ) and
the percentage of cadmium removed (η), which are
calculated as follows.[13]
Veff = Fte
RESULTS AND DISCUSSIONS
(6)
(7)
(8)
Elution efficiency is calculated as follows:
100
Cadmium Concentration (mg/l)
574
80
60
40
20
0
0
E (%) = md × 100/mad
(9)
where F is the volumetric flow rate (ml/min) and md
is the mass of metal desorbed that was calculated from
the elution curve (C vs t).
 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
10
20
40
30
Time (h)
50
60
70
Figure 1. Breakthrough curves for cadmium biosorption
onto S. tenerrimum at different bed heights (flow rate =
5 ml/min, initial cadmium concentration = 100 mg/l, pH =
15 cm,
20 cm,
25 cm.
6)
Asia-Pac. J. Chem. Eng. 2008; 3: 572–578
DOI: 10.1002/apj
Asia-Pacific Journal of Chemical Engineering
BIOSORPTION OF HEAVY METAL USING BROWN SEAWEED
Table 1. Column data and parameters obtained at different bed heights and constant flow rate.
Bed height
(cm)
15
20
25
a
Flow rate
(ml/min)
Uptake
(mg/g)
tb (h)
te (h)
t (h)
(dc/dt)a
(mg/l h)
Total removal
(%)
5
5
5
68.23
68.86
69.37
15.8
19.7
23.9
45.6
52.0
58.1
29.8
32.3
34.2
4.361
3.824
3.262
56.96
60.82
60.47
Slope of the breakthrough curve from tb to te .
25
Service time (h)
20
15
10
5
0
0
10
20
Bed height (cm)
30
Figure 2. BDST model plot for cadmium biosorption
by S. tenerrimum (flow rate = 5 ml/min, initial
cadmium concentration = 100 mg/l, pH = 6).
shows that the flow rate largely affects the sorption
capacity. The total cadmium removal percentages for
5, 10 and 20 ml/min are found to be 60.47, 59.82
and 47.23%. Because of the unavailability of sufficient
retention time for the solute to interact with the sorbent
and the limited diffusivity of the solute into the sorptive
sites or pores of the biomass, a reduction in the cadmium uptake capacity is observed at higher flow rates.
o
A plot of ln [ C
C − 1] against t (where t = V /F ) for
a given flow rate can be used to determine the Thomas
model constants.[13] Figure 4 shows the linear nature of
the model yielding a good fit for the experimental data
at all flow rates with correlation coefficients greater than
0.978. The parameters of the Thomas model evaluated
at the three flow rates are reported in Table 2.
Regeneration studies
Effect of flow rate
Most of the industrial scale treatments of heavy metal
removal from effluents are accomplished in a continuous mode and hence the study of the effect of
flow rate on sorptive characters becomes an important
criterion.[17] In the present work, the sorption capacity
of S. tenerrimum is studied for various flow rates in the
range of 5–20 ml/min for the initial cadmium concentration of 100 mg/l and bed height of 25 cm. Figure 3
represents the trend of the variation in the effluent cadmium concentration against time for the flow rates of 5,
10 and 20 ml/min. An earlier breakthrough and exhaustion times were observed in the plot for the flow rate
of 20 ml/min. Also, it can be inferred that the cadmium
uptake dropped as the flow rate was increased. The values are reported as 69.37, 64.37 and 51.53 mg/g for the
flow rates of 5, 10 and 20 ml/min respectively, which
 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
The concept of regeneration of biosorbents is important
in industrial applications for the removal of metal from
Cadmium concentration (mg/l)
were found to be 3819.42 mg/l and 0.0353 mg/h respectively. The rate constant Ka , which is a measure of the
rate of transfer of solute from the fluid phase to the solid
phase, largely influences the breakthrough phenomenon
in the column study.[16] For a smaller value of Ka , a
relatively longer bed is required to avoid breakthrough,
whereas the breakthrough can be eliminated even in
smaller bed heights when the value of Ka is high.[16]
100
80
60
40
20
0
0
10
20
30
40
Time (h)
50
60
70
Figure 3. Breakthrough curves for cadmium biosorption
onto S. tenerrimum at different flow rates (bed height =
25 cm, intial cadmium concentration = 100 mg/l, pH =
6). . .predicted from Thomas model. Flow rates: 5 ml/min,
10 ml/min, 20 ml/min.
Table 2. Thomas model parameters.
Flow rate (ml/min)
5
10
20
Kth (l/mg h)
Q0 (mg/g)
R2
0.0023
0.0044
0.0053
79.827
65.983
51.591
0.979
0.989
0.992
Asia-Pac. J. Chem. Eng. 2008; 3: 572–578
DOI: 10.1002/apj
575
N. RAJAMOHAN AND B. SIVAPRAKASH
Asia-Pacific Journal of Chemical Engineering
2
1
0
0
10
20
30
40
50
60
-1
-2
-3
t (h)
Figure 4. Prediction of Thomas model parameters
20 ml/min, 10 ml/min, 5 ml/min.
waste water. Reusability of sorbent can be evaluated
by comparing the sorption potential of regenerated
biomass with the original biomass. In the present study,
five sorption–desorption cycles were carried out in the
packed column with 19.15 g of the biomass yielding
an initial bed height of 25 cm, bed volume of 88.3 ml
and a packing density of 216.87 g/l. The analysis was
made for a period of 15 days continuously with 128.352
l of cadmium solution having an initial concentration
of 100 mg/l. The elution process was carried out with
14.311 of 0.1 M HCl. Table 3 summarizes the values
for breakthrough time, exhaustion time and cadmium
uptake for the five cycles. At the end of the fifth
cycle, 14.12 g of dry biomass was left in the column,
indicating a weight loss of 26.27%. The bed height
dropped to 23.1 cm from 25 cm and the bed volume
got reduced to 81.2 ml. The packing density was found
to be 173.89 g/l after five sorption–desorption cycles.
Figure 5 represents the breakthrough curves for the
regeneration cycles, wherein it can be observed that the
breakthrough time showed a decreasing trend, whereas
the exhaustion time increased progressively. The cycles
were run till the exhaust limit reached 99.8 mg/l of
cadmium to avoid the time delay that normally occurs
for full bed saturation. The actual length of the bed
and the slope of the successive breakthrough curves
decreased during the course of the regeneration cycles.
The loss of sorption performance is not mainly due to
biomass damage but rather because of sorbing sites,
whose accessibility becomes difficult as the cycles
progresses.[18] The loss of sorption performance was
not reflected in the biosorption capacity, as it remained
reasonably consistent irrespective of the number of
cycles. The uptake also strongly depended on the
previous elution step, since prolonged elution may
destroy the binding sites or inadequate elution may
allow metal ions to remain in the sites.[19] After five
sorption–desorption cycles, it was found that the S.
tenerrimum biomass exhibited a high cadmium uptake
of 64.32 mg/g, which shows the ability of selected alga
to retain its biosorption capacity and withstand extreme
operating conditions.
In regeneration operations, the activity of biosorbents
is estimated in terms of ‘life factors’. The life factors
are dependent on the minimum bed height (Zm ) or
the critical bed height, which is defined as the height
required to obtain the breakthrough time tb at t = 0 [20].
The life factor was calculated in terms of the critical bed
height using linear regression given by
Zm = Zm,0 + kL x
(10)
where x is the cycle number, Zm,0 is the initial critical
bed height (cm) and kL is the corresponding life factor
(cm/cycle). The plot of Zm vs x (Fig. 6) gives the values
of Zm,0 and kL as 14.626 cm and 0.4037 cm/cycle,
respectively. The desorption process and agents for
continuous operations should be selected in such a
way that they are not only effective but also should
not damage the sorbents. In all the five cycles, the
100
Cadmium
concentration (mg/l)
3
ln [(Co/C)-1]
576
80
60
40
20
0
0
10
20
30
40
Time (h)
50
60
70
Figure 5. Breakthrough curves for cadmium concentration onto S. tenerrimum biomass during regeneration cycles
(initial bed height = 25 cm, flow rate = 5 ml/min, initial cadmium concentration = 100 mg/l, pH = 6). Sorption cycles:
1 cycle,
2 cycle,
3 cycle,
4 cycle,
5 cycle.
Table 3. Regeneration data and elution efficiency.
Cycle no
1
2
3
4
5
Uptake (mg/g)
tb
(h)
te
(h)
t
(h)
dc/dt
(mg/lh)
Z
(cm)
Zm
(cm)
Veff
(l)
Cadmium
removal (%)
Elution (%)
69.37
70.75
70.58
67.22
64.32
23.9
23.4
22.5
20.8
18.7
58.1
60.8
61.2
63.8
64.0
34.2
37.8
38.7
43.0
45.3
3.262
2.823
2.517
2.323
2.189
25.0
24.2
23.8
23.4
23.1
15.105
15.429
15.471
16.176
16.750
17.43
18.24
18.36
19.14
19.20
60.470
60.843
60.392
55.163
60.243
99.451
99.280
99.414
99.437
99.515
 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
Asia-Pac. J. Chem. Eng. 2008; 3: 572–578
DOI: 10.1002/apj
BIOSORPTION OF HEAVY METAL USING BROWN SEAWEED
20
7
18
6
16
5
sorption pH
Minimum Bed height (cm)
Asia-Pacific Journal of Chemical Engineering
14
12
3
10
2
8
1
6
0
0
10
20
4
2
0
1
2
3
4
30
40
50
Sorption time (h)
60
70
80
Figure 8. Sorption pH profiles during regeneration
cycles (bed height = 25 cm, flow rate = 5 ml/min,
initial cadmium concentration = 100 mg/l, elutant =
0.1 M HCl)
1 cycle,
3 cycle,
5 cycle.
0
5
Cycle no
Figure 6. Life factor chart.
3.5
3
2.5
Elution pH
elution curves (Fig. 7) showed a similar trend with a
sharp increase at the start of operations followed by a
gradual decrease. The elution efficiencies were always
greater than 99.2% throughout the experiment. The
elution process was carried till the effluent cadmium
concentration reached 5 mg/l.
In Figs 8 and 9, the pH profiles of sorption and
elution process for cycles 1, 3 and 5 are shown. In
brown algae, the metal binding mainly occurs by the ion
exchange mechanism due to the presence of carboxylic
and sulfonic groups as the two key functional groups.[18]
In the present investigation, when the protonated
biomass was brought in contact with the Cadmium solution Cd2+ , it exchanged with H+ ions to occupy the
binding sites; hence, the pH dropped. In all the sorption
cycles, the effluent pH continuously decreased as the
saturation of the bed progressed and finally stabilized
near 3.0. The pH profiles and elution curves showed a
similar trend, and it was inferred that the pH shoots up
2
1.5
1
0.5
0
0
2
4
Elution time (h)
6
8
Figure 9. Elution pH profiles during regeneration
cycles (bed height = 25 cm, flow rate = 5 ml/min,
initial cadmium concentration = 100 mg/l, elutant =
1 cycle,
3 cycle,
5 cycle.
0.1 M HCl)
in the initial stages and decreases gradually. This is due
to the exchange of the H+ ions provided by the elutant
(0.1 M HCl) with the Cd2+ ions in occupying the sites,
wherein the pH of the solution increases up to the point
where the cadmium concentration reaches the peak in
the effluent. Further, when the effluent cadmium concentration decreases, the effluent pH also decreases and
eventually reaches the influent pH. Thus, the pH profiles of the sorption and elution cycles ascertain that the
mechanism involved in biosorption of cadmium by the
selected marine alga, S. tenerimmum, is ion exchange.
4000
Cadmium concentration (mg/l)
4
3000
2000
1000
0
0
2
4
6
8
Time (h)
Figure 7. Elution curves for cadmium during regeneration
cycles (flow rate = 5 ml/min, elutant = 0.1 M HCl). Elution
1 cycle,
2 cycle,
3 cycle,
cycles:
4 cycle,
5 cycle.
 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
CONCLUSIONS
The adsorption behavior of nonconventional and costeffective sorbent prepared from marine alga S. tenerrimum has been investigated for the removal of cadmium
Asia-Pac. J. Chem. Eng. 2008; 3: 572–578
DOI: 10.1002/apj
577
578
N. RAJAMOHAN AND B. SIVAPRAKASH
ions. After five sorption–desorption cycles, it was found
that S. tenerrimum biomass exhibited a high cadmium
uptake of 64.32 mg/g, which shows the ability of S. tenerrimum to retain its biosorption capacity and withstand
extreme operating conditions. The sorption performance
has increased only slightly with an increase in the bed
height. The BDST model constants were evaluated and
proposed for use in the continuous column design. The
Thomas model was found to fit the column data reasonably well at various flow rates and the model constants were determined. Thus, high sorption efficiency,
reusability of the alga and highly efficient elutant make
this process an effective and economical alternative for
the removal of cadmium ions from metal-bearing industrial effluents.
REFERENCES
[1] R. Salim, M.M. Al-subu, E. Sahrhage. J. Environ. Sci. Health,
1992; A27(3), 603–627.
[2] C.W. Cheung, J.F. Porter, G. McKay. J. Chem. Technol.
Biotechnol., 2000; 75, 963–970.
[3] C.W. Cheung, J.F. Porter, G. McKay. Water Res., 2001; 35,
605–612.
 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
Asia-Pacific Journal of Chemical Engineering
[4] A. Perez-Martin, B. Meseguer, V. Zapata, J.F. Ortuno,
M. Aguilar, J. Saez, M. Llorem. J. Hazard. Mater., 2007; 139,
122–131.
[5] P. Lodeiro, J.L. Barriada, R. Herrero, M.E. Sastre de vince.
Environ. Pollut., 2006; 142, 264–273.
[6] Z.R. Holan, B. Vlesky, I. Prasetyo. Biotechnol. Bioeng., 1993;
41, 819–825.
[7] Z. Aksu, T. Kutsal. Process Biochem., 1998; 33(1), 7–13.
[8] D. Kratochvil, B. Volesky. Trends Biotechnol., 1998; 16,
291–300.
[9] C.E. Borba, R. Guirardello, E.A. Silva, M.T. Veit, C.R.G.
Tavares. Biochem. Eng. J., 2006; 30, 184–191.
[10] T.S. Singh, K.K. Pant. Sep. Purif. Technol., 2006; 48,
288–296.
[11] A.D. Faust, O.M. Aly. Adsorption Processes for Waste
Treatment, Butterworth Publishers: USA, 1987.
[12] B. Chen, C.W. Hui, G. McKay. Langmuir, 2001; 17,
740–748.
[13] Z. Aksu, F. Gonen. Process Biochem., 2003; 39, 599–613.
[14] Z. Zulfadhly, M.D. Mashitah, S. Bhatia. Environ. Pollut.,
2001; 112, 463–470.
[15] D.O. Cooney. Adsorption Design for Wastewater Treatment,
CRC Press: Boca Raton, FL, 1999.
[16] M. Zhao, J.R. Duncan, R.P. Van Hille. Water Res., 1999; 33,
1516–1522.
[17] B. Volesky, J. Weber, J.M. Park. Water Res., 2003; 37,
297–306.
[18] K. Vijayaragavan, J. Jegan, V. Palanivelu, M. Velan. Chem.
Eng. J., 2005; 106, 177–184.
[19] T.A. Davis, B. Volesky, A. Mucci. Water Res., 2003; 37,
4311–4330.
Asia-Pac. J. Chem. Eng. 2008; 3: 572–578
DOI: 10.1002/apj
Документ
Категория
Без категории
Просмотров
1
Размер файла
121 Кб
Теги
using, regenerable, metali, biosorption, brown, heavy, seaweed, column, continuous
1/--страниц
Пожаловаться на содержимое документа