AB 1
C D @ $; ($ + ( , - ! *( < " =% >?4 , " E ( 0 " F$ 7
5
C D D 8'2?
F
G
H :!'
4
8
8 E
,8 B
8 A! ? : 8 B F
)+ :
(KQ/U/VT N O,
KK/P/JM 4
)
8 2 G ,2* ) !N *0 EWH * K / o7 o,7 ,N;Y 'l , , $ / - p * p 'l ?! 3 / Z; P .2 / 0 W* +2. 2 ! ) = ] ?! 3 'l , ?! 3 . 3 0 +2. 0 W* - p * 0 ?! 3 Z. - & * 0= / / ? 7 [ 7 . I 3 / !* / 3 !N *0 q 27 R7b * ->2* .2. ) >2* - * a 3 WX Y 0 e *! >2* +/ $ 3 , : , R7b ,* >2* 'l _3! o7 / - 'd 0= / / ? 7 0 W* ) [ 7 .2 I +/ $ 3 / !* 'd >/ 'd, / ?! ,3 s / H* .2 = r ! 0 W* / !* R7 'd !:I B I !&7 0 7 ! e *! >2* ) J - .2 = * .2 / 0 H* ?( * s / H* o7 -
" < " @) ( 7 ! 8
9 : %;
!%< = (
>? :
"7N
Using Thomas Model to Evaluate Dye Removal from Aqueous Solutions in Fixed-bed Columns of Activated Carbon Mahdi Hadi 1
Mohammad Reza Samarghandi2
Mohammad Taghi Samadi
4
Reza Shokoohi
(Received Oct. 13, 2009
2
Saeed Azizian 3 Alireza Rahmani 4
Accepted July 21, 2010)
Abstract
For the purposes of this study, activated carbon was derived from pine-cone by a chemical-thermal process. Initially, its chemical and physical properties were determined before it was used for the removal of Acid Black 1 and Acid Blue 113 dyes. A batch sorption study was carried out in order to obtain the optimum isotherm model. The monolayer maximum saturation capacities of AB1 and AB113 dyes based on Langmuir isotherm model were determined to be 458 mg dye/g carbon and 286 mg dye/g carbon, respectively. Adsorption of dyes was also studied in a continuous-flow state using a fixed-bed column of activated carbon. The effects of operating variables such as flow rate, bed depth, and dye concentration on the column operation were studied. Data confirmed that the breakthrough curves depended on flow rate, bed depth, and initial dye concentration. Column behavior was investigated using Thomas Model and model parameters were determined by a non-linear regression method. The Langmuir and Freundlich isotherm models were used to fit the experimental data. The best fit of the adsorption isotherm data was obtained using the Langmuir model for both dyes. The results showed that Thomas Model was suitable for the description of breakthrough curves under the experimental condition. The column adsorption capacity was also compared with equilibrium adsorption capacities for each dye.
Keywords: Dye Adsorption, Fixed –Bed Column, Thomas Model, Acidic Dyes. 1. Faculty Member of Environmental Health, Enironmental Health Research Center, Faculty of Public Health, Kordestan University of Medical Sciences (Corresponding Author) 09189061738
[email protected] 2. Assist. Prof. of Environmental Health, Faculty of Public Health, Hamadan University of Medical Sciences, Hamedan 3. Prof., Dept. of Chemistry, Bu-Ali University, Hamedan 4. Assoc. Prof. of Environmental Health, Faculty of Public Health, Hamedan University of Medical Sciences, Hamedan
23
a$L 6 B ? R$RL' M8 a$L 6 B J ,$ "# 31 213/ m;2 (+",-") & 8 6M N" ( 6 B
[email protected] & 6M N" ( 6 B a$L 6 B J 54 & "B ( $6 $6 J 5; & 6M N" ( 6 B a$L 6 B J $ 50
' F1 I ! 6 ,+- 1 ! L F & A L" ." • $ " = ; < #$ . /! ? #6 ? l B/ L* " .L" ! ? • \ A ~ A # • S< "= .[C…] #$ \ A .& $ F 0 3 • L" ! : $ & A & $ / #1 = .#$ ™ * ~A *7 ' F1 I R @ Z (l ! k". Acid Blue113 * Acid Black1 :" z ! 0E = ." :" f / i` " * ,+ ( & > #F E A 6 #F E & e F E ,+ E& ! # +D ! $ R e #F E * ! $* #F E ! $ ~N < * ~N < & " < *! g ! +- „ k ™ .[sVC] 6l #6 ! o l g .:" a .# $ w I I l #6 ! :" D 0?) p & D i` 8 4 ! :!* ™ :" < " 1 . > #F 5; i` ! ! .[|VW]" < ?T 1 7@ ." 0 ( 4g ! 6 " > \ i` ™ A* ." 6. R* ( lI$ 4 p $ ." #D $ * 0> : !& ; $ ' H 4g ! 6 .". B. < ' A ? T .B4A !* "1 ! 6 * o l *& 6 # i$‘ = .[…V| * W] " 6. :" ! k~ = 3 *# 3&! 4 * ! : 4 #6 ! # .!™ " 1 . > < * A 6 4 i` ! ™ .[U * |] # $ > F$ L = . )< :} * 4 g 4 i` * * B. < + - .b* 4 * ! .# $ 3 $ *B ! lI$ . ) N :" < " 6 < 0 D .:" < "(F ! : $ & ." * ?1 ." 6 1 < ." ! .[COV| * W] : lI$ ~A .p ? * ? T 1 A # + 3*: & ! lI $ ~ A " < @ #$ 3 # 1* 4 * $ #56 : $ = ; 8 < 7. ¤ l1 lI $ ~A " .[… * U y W] #56 # $ 6 = R"D * :4 #1 4$ & $ * g .:" a k~ = p ? 2$ :!* Y$ "@ : $ E i ` # < 54 : " &" p) > .z+ ! R WQ "( zŽ$ ." " : 3 • 6+$ A #56 * "E …W p 6 " $ ! -) 8@= :" " $ > .z+ •I$ < l " M +- CQ C WQ I3 7+ < p 0> +E = M +- ." )N ? ?1 : < 0> * " 0( + OWQ L ;* + ; #D $ m '" & h " @ &" p)> 4 L l ." $ y/W &" p) > ! z / * " : 3 A COQ &* 4?1 ! & L 5 * " > . g) ! &* . ! : $ :" p 1 . < ." : 5D WQ * sQ mQ OQ B *" M +- g "? WQ * sQ mQ 4?1 * :" 3 ) I 0> # ; ~A! +A F + Q/W ' \ o$ :! " ." : 3 6 ." 0/ W )V ] ;D^ W 0' p !: $ " 1 L F < (SMB) •I$ :} * #= 6 + + ™ ~A 4 # +N F Z ; ! b* .[OQ] " F • 6+$ A OQ # H \ A o$ ! ~ A b* ! : $ \ A :} * #= 6 "( f . ' ( (l : g) ! BET *7 L" o $ &T* ." F # #F E : g).*}/ #6 1 < LF < 84 6 ' -) ! ? (IN) " "D L F •I $ :" . & ) 3 * / "( ." 6= L F ; .# $ \ A ~ 7 • $ •I$ * \ A > !" a " "D < \A !: $ " "D .[OC] " > ,+ - ' 5 < ~A .[OO] " F ASTM D4607-94 " $ b* " 1 \ A : ! R W C (d) F3 * 6 F * k • R A "( * " - _-) 8@= k • K :" ! > 8 @= , k • ." :! " \ A : • > #D $ K '" 0E = M +- zŽ$ * :" / &" $ ! " F ." :" A \ A : ~ ! .&
25
Z +F & #> $ &* : g $ ! : $ & < p)> pH : g $ ! : $ 41 +l pH ." R @ 2; • / #< Mi > ." :! " PP-50 L" • $ 1 @ 86 $! : $ # H Š g 41 +l j L" ? 0 > IS12 ¦ 6 < L" (1 &7 . n & 6 < L" ? ?1 : < ." R @ WTW- TS606/2i :! " ." : $ • < .M* - & < :7 < pŽ $ * ?Ž $ : g $ ! : $ 7 ™ # +N ." R @ UV-1700 L" t*! 6 # + , +, x / ; l ! L F .M* ." * A & " . ? 7/ R +D : g) 0 ( R u < *! ™ p & D ( AB113) Acid Blue 113 ™ ™ f . * #$ > > $ *! :* * < 1 $ *! ™ p & D (AB1) Acid Black 1 *! " ' * @ 0 6 $
15
' +)E ( t 0/ W )V ' " Z (l ! += L F 4 *" 1 zŽ $ ." " > : g) ! L ( ! " F • .M* " •! k~= • .M* - ! :" 0E = .z+ 1
Oxitop Exiton 3 Pharmaspec Shimadzo 4 Disazo 2
+= ! 0 E = ‹ ." R @ * ?Ž$ : g $ 3 $ & ! #56 # +N ' X ! 8$ " $ E & ! #56 # +N ' X !*# ." #5H L F & ! & D * ? 7 ' -) * :" • < M* - ! :" " 1 +
:! " . 1 LF 6
/
& * # $ Q/QyOW " $ 4 +N : 6 2 F1 I 4g 4 +N : 6 * Acid Black 1 ™ ! 1 R + CQQ ™ ! 1 R + CQQ Q/COW " $ " $ L +l . ~ A " ( ." 4 Acid Blue 113 * yOO S< " = • L ; Acid Black 1 ™ W|s S< " = • L ; Acid Blue 113 ™ I> & $ b* ! : $ # 4 ." #5H * #• 3 b! " $ M( * $ o> Excel 7 R p < 2 . ( R ) F 2 ` "( : . o> 1 F * " : ." 5$ l ™ _F * q ,' u< _r*
0'
s
" O \< + J
u< _r*
0' !
W 0' 2 J
*
. ~ A L F & ! & * #$ F1 I 1* # +N ™ . ! + OWQ 8@= 1 +l ™ " 1 L F < ! R Q/CO "( * 4 1 R + CWQ pH " ( ." - 1 . 0> 7@ ; :" " 3 ! z / ." 8 | y/W 1 . g 41 +l . & . 2 $ b / * 1 . 0> # g & OQ ? 0> 6 ; X &7 . p * 1 1 .! zŽ $ .# 3 • 6+$ A "F . ™ # +N :! " * _-) ! 0E ! : $ mUQQ RPM * ( 3 W '" T $!
26
1 + CQ 41 $ . ." R @ mUQQ RPM * ( 3 W '" &" T $ ! "F ." ' * ` ' E ." :! " 4 ™ # +N "( ." " Z 3 5$ #56 # +N * & ~ A ™ "( • $ "( ." F & 1 F# • 5D . 6 ( I( #1 = Ct 1 = C0 1 + exp(k q m Th 0 Q
~ A ™ " ( qo R R Am R 1 + 26 = R + 26 =
27
B/
2 K
< $
.L" ! ? 3: #H 6 L" .[C…] : &) O ! F #6 ? l ) ! *"< B/ J #6? $ \ A R A "= * ! :" *7 # • "( " :" ~A : ~A \A
k Th C0 t )
(O)
I < L mg min 26= • # H Kth + 26= \ A R A "= * ! :" @= Q & $ 0> L F < t& ! A* > ™ # +N Ct ( 3 .#$ ( 3 26= & ! t 1 -1
-1
v =v w )#xv !,#v
" O \ ! ." : $ & $ :" "4g & D ) 8)/ ! 6 /* 4+l ! < .L •* > ! +A f. !p R m 0? ." : $ ) 8)/ ! .". & ) Z (l : $ & $
:
$
CW CQ 4D * Cs/W … #56 < R Q/m # •0"5 \ AR R
uv< %rvE s
. g) ! & $ ! p
R
15
!p . Š \ A R A "( 2 & $ 0? A $ OQ * : 6 "( f . ." F R C… & $ #$ 8@= & $ \ AR A / ." F 2F? $ + • L" ! :" 5$ l J ~A ." : $ ." / L F < ! $ OQ „ & $ ™ # +N :! " 1 = . I> B. < ( 3 mQ '" " 6 < 5N A* 0 1 & $ 0 < ) 6 ! "F ." T Ž / & $ 0> I( * 0 ™ &7 * * i` ™+ I( U/Q| 1 R + CWQ 1* # +N ™ L +l 6 , < ™ &" * l1 ! ." ~X ( 3 1 + 0E ." # 5H .& ! & $ & $ $ OQ * CW CQ 4D ! , + !
u< _r* O)' A + ) } { 1* 9 $ B ! R @ Z ; ! L F & ! F ! z/ . 8. ~ A ' + D 1 F .B ! R @ & 9 & D # l ha F 1 F .B ! ! + E = .: / .: .: ." > ~A .R *7 ." 6= lI $ ~A .8 6 $ = ; F lI $ ~ A K $i .L" ! y 0? Z I M 5 g " K † 1" * * g a .L" " 6 . L +l * \ A : :" k~= : # +N 1 F * g a .L" . / O L*" A .[O| * Oy OW] L F < o $ AB1 * AB113 ™ ~ A † 1" * * F 2 ` ( < ;& . .#$ :" : * • < 1 *7 L" " . & ) B. < X2 : "( f . +I l # $ 6 ™ * . ga g ' 5D * " *7 B ! ‹ :" < 5 *7 B ! ‹ † 1" * *7 L" #56 L" . 4 — 5I 8 ' + )w+ ) { { #6 9 :" "/ & $ 4 ~A L F = " &" $ ." $ (Cb=0/02Co )Cb ™ # +N * " — & $ & $ +- I( # +N & $ &" „ 5 zŽ$ ! 6 #6 9 I( F1 I . (Cx=0/9Co)Cx # +N " E O "( & $ ! A* > i` # +N l1 7 & $ +- I( f . ." $ * * i` ." $ * * i` # +N "E …Q A* > # +N ! '* 4D 6 #6? . l ‡ 0? ™ ! 1 R + CWQ & 6 ? * * # +N 6 (3 1 + ˆ/–‡& 6 ? * * f . * AB1 6 „ B7 :" < ;& . .". & ) : 6 [ D +J6 < < #6? l 2 +- I( &" $ & ! 2 * :" R A L ( = &" &" $ & ! :" < I . .". B 7 & $ ( 3 u––– *" = $ n– „ & $ #6? I( ~A 6 A 0 3 0 6 / :" . & ) +J6 . j‡ *" = ( Cb=0.02Co) & $ #6 ? .# $ AB1 ™ L*" A < ;& . . — & $ < „* ! "F ( 3 ~ A# •& . < ~A # • #$ :" : & ) t n– j– ! & $ „ B7 • L" 5 ™ ~A • $ #= 6 B 7 0 1 $
`U a #< { 0' ! { & ! lI $ ~ A .8 6 $ = ; < @ ! +< ; = ; # $ # . 7• = \ A L F &" $ #$ R!a . F L F & ! #$ R!a \ A 8 6 $ lI $ ~ A .8 6 $ = ; • $ # A +J6 $ !a * #$ " 8 = .R *7 ! . & ! X #56 ~A ' + D R @ #D $ F1 I .R *7 .[Os] " B * 9 $ F1 I & wiIE #$ & * #$ ~ A K $ $ R @ ! 1* @ 3 * & / &" _-) ". > L F & ! 4g ~A L F I( & ! . * #$ ~A .R *7 jj––– *" = v * u 4+? Z I 2 AB113 * AB1 # • &" 0 < ! & ; * ! ." F (3 * . L F& !™ * ~A < \ A ~A ." !* j– ™
'*
4D & $ #6? l V 15 AB1 ™ k~= L F $ & 1 ?1 > $ * #$ R {ˆj/{v & 1 ?1 &!* {jˆ/vu 1 ?1 &!* * &7 (+= u AB1 ™ ! 2 AB113 ™ < [ D +J6 .#$ d 7 R ~ $ " 1 ?1 > $& # 01 4D * ! *" $ A & ! ; 6 &" „ 5 ~1 ." < ' A 4 & $ a .L ?1 < AB1 ™ 6 ( : < L" . / t L*" A ." — # $ pe < AB113 ™ ~ A & $ ,+ + Do • „ B7 :". ) < ;& . ." :" : & )
29
/V
*
~ < )/
–/•ˆˆ –/••‡
'*
.
2
R
n
k
–/•ut –/•ˆ‡
‡/v{ v/‡u
nvt/u{ jnu/jv
'* LF
k~= & $ #6?
0?
u< O
< ". & ) n* j 4+? ." A 0 3 F1 I ™
AB113* AB1
4g
Co (mgL-1)
~A & $ ,+ qo (mgL-1)
+ Do
qo (mg g-1)
•
= /)‚ 0'
L"
.
0')xV +)
/ "(
*
Kth×10-4 (L mg-1 min-1)
8 '+ (cm)
(mL min-1)
Adj. R square
Reduced Chi- 2
–/ˆtu –/ˆn• –/ˆu‡ –/ˆn• –/ˆ‡ˆ –/•t{ –/ˆ•v –/ˆn• –/ˆvˆ
–/–j{ –/–jv –/–jv –/–jv –/–jn –/––‡ –/––• Q/QCW Q/QCO
juˆ/t‡ ju•/{ jvn ju•/{ ju•/{ ju•/{ j•ˆ/n ju•/{ •ˆ
nt–‡v/–uj t‡u•t/j‡n v•tuj/{‡v t‡u•t/j‡n vv•u{/{uj •–ˆ‡{/vjˆ n{‡{v/ˆ{n t‡u•t/j‡n tvttt/tn–
‡{/•j‡ jnu/•‡‡ j•‡/ˆ–{ jnu/•‡‡ jˆ{/uˆ• t–n/•nn ˆ•/nn– jnu/•‡‡ jj‡/‡‡ˆ
u{–/ˆ{• u{–/•–j u{–/•–n u{–/•–j u{–/•–j u{–/•–j u{j/ˆvv u{–/•–j uvˆ/ˆ{{
j{/{•– n‡/jj{ un/•jj n‡/jj{ u–/u{n {v/‡nu j•/tjˆ n‡/jj{ nv/{{‡
–/{t‡ –/nvu –/j{u –/nvu –/juˆ –/–•t –/tˆˆ –/nvu –/tjˆ
10 10 10 10 15 20 10 10 10
10 ˆ/–‡ { /j ˆ/–‡ ˆ/–‡ ˆ/–‡ ˆ/–‡ ˆ/–‡ ˆ/–‡
0/897 0/895 0/804 0/895 0/851 0/883 0/702 0/895 „/••
0/009 0/011 0/016 0/011 0/015 0/013 0/018 0/011 0/01t
151/4 150/54 149/2 150/54 150/54 150/54 201/86 150/54 99/69
6835/494 7182/509 8891/151 7182/509 6603/364 9083/770 4607/953 7182/509 8408/483
22/785 23/942 29/637 23/942 22/011 30/279 15/360 23/942 28/028
283/718 283/636 283/507 283/636 283/636 283/636 287/351 283/636 276/466
8/031 8/441 10/454 8/441 7/760 10/675 5/345 8/441 10/138
2/250 2/520 1/290 2/520 1/650 0/ 860 2/180 2/520 2/270
10 10 10 10 15 20 10 10 10
10 •/„€ •/ •/„€ •/„€ •/„€ •/„€ •/„€ 8/07
.# +N
AB113 ™
AB1Cm ™
(mg g-1) AB1
AB113
k~= & $ #6? '* 1*
l
… 15
< '" * AB1 ™ 4A 0 3 . $01
"
!:
Al-Degsa et al.
&*+) J 1- Rajgopalan, S. (1995). “Water pollution problem in the textile industry and control.” Trivedy, R. K. (Ed.) Pollution Management in Industries, Karad, India. 2- Ali, M., and Sreekrishnan, T. R. (2001). “Aquatic toxicity from pulp and paper mill effluents- a review.” Adv. Environ. Res., 5, 175-196. 3- Koplin, D. W., Furlong, E. T., and Meyer, M. T. (1999-2000). “Pharmaceuticals, hormones and other organic wastewater contaminants in US streams.” Environ. Sci. Technol., 36, 1202-1211.
32
4- Routh, T. (1998). “Anaerobic treatment of vegetable tannery wastewater by UASB process.” Ind. J. Environ. Prot., 20, 115-123. 5- Ramakrishna, K. R. (1996). Dye removal using peat, American Dyestuff Report Saskatchewan, Canada. 6- Ho, Y. S. (2006). “Scond-order kinetic model for the sorption of cadmium onto tree fern: A comparison of linear and non-linear.” Water Res., 40, 119-125. 7- FU, Y., and Viraraghavan, T. (2003). “Column studies for biosorption of dyes from aqueous solutions on immobilized aspergillus Niger fungal biomass.” Water S. A., 29, 465-472. 8- Tsui, L. S., Roy, W. R., and Cole, M. A. (2002). “Removal of dissolved textile dyes from wastewater by compost sorbent.” Color Technol., 119, 14-18. 9- Yeddou, N., and Bensmaili, A. (2005). “Kinetic models for the sorption of dye from aqueous solutionby claywood sawdust mixture.” Desalination, 185, 499-508. 10- Ghanbarian, M., Mahvi, A. H., Nabizadeh, R., and Saeedniya, S. (2009). “A pilot study of RO16 discoloration and mineralization in textile effluents using the nanophotocatalytic process.” J. of Water and Wastewater, 69, 45-51. (In Persian) 11- Rahmani, A., and Samarghandi, M. (2009). “Electrocoagulation treatment of color solution containing colored index eriochrome black T.” J. of Water and Wastewater, 69, 52-58. (In Persian) 12- Naeem Abadi, A., and Movahedian Attar, H. (2008). “Decolorization and biological degrandation of Azo dye reactive Red2 in anaerobic baffled reactors.” J. of Water and Wastewater, 65, 30-37. (In Persian) 13- Reddy, S. S., Kotaiah, B., Reddy, N. S. P., and Velu, M. (2006). “The removal of composite reactive dye from dyeing unit effluent using sewage sludge derived activated carbon.” Turkish J. Eng. Env. Sci., 30, 367373. 14- Kadirvelu, K., Karthika, C., Vennilamani, N., and Pattabhi, S. (2005). “Activated carbon from industrial solid waste as an adsorbent for the removal of Rhodamine-B from aqueous solution kinetic and equilibrium studies.” Chemosphere, 60, 1009-1017. 15- Namasivayam, C., and Kavitha, D. (2002). “Removal of congo red from water by adsorption onto activated carbon prepared from coir pith, an agricultural solid waste.” Dyes Pigments, 54, 47-58. 16- Saeedi, M., Jamshidi, A., Abessi, O., and Bayat, J. (2009). “Removal of dissolved cadmium by adsorption anto walnut and almand shell charcoal : Comparison with granular activated carbon (C-AC).” J. of Water and Wastewater, 70, 16-22. (In Persian) 17- Asilian, H., and Mahmoudi, M. (2009). “Adsorption of AZO reactive red 198 from aqueous solutions by the sludge of water treatment plant coagulation unit.” J. of Health and Environment, 1(7), 93-102. (In Persian) 18- Ghaneeian, M. T., Ghanizadeh, Gh., Gholami, M., and Ghanderinasab, F. (2009). “Application of eggshell as a natural sorbent for the removal of reactive Red 123 dye from syuthetic thentile wastewater.” J. of Zahedan Medical Sciences Researchs, 11 (4), 25-34. (In Persian) 19- Thomas, H. C. (1994). “Heterogeneous ion exchange in following system.” J. Am. Chem. Sec., 66, 16461664. 20- Arnepalli, D. N., Shanthakumar, S., Hanumantha Rao, B., and Singh, D. N. (2007). “Comparison of methods for determining specific-surface area of fine-grained.” J. of Geotech. and Geological Eng., 26 (2), 121-132. 21- Noszko, L., Bota, A., Simay, A., and Nagy, L. (1984). “Preparation of activated carbon from the by-products of agricultural industry.” Periodica Polytechnica Chemical Eng., 28, 293-297. 22- ASTM. (1999). Standard test method for determination of iodine number of activated carbon, D4607-94, USA. 23- Rudenko, M. F., and Palagina, I. G. (2000). “Determination of the physical characteristics of activated carbon for adsorption refrigerators.” Chemical and Petroleum Engineering, 26, 507-509.
33
24- Ho, Y. S., Chiu, W. T., and Chung, C. W. (2005). “Regression analysis for the sorption isotherms of basic dyes on sugarcane dust.” Bioresource Technol., 96, 1285-1291. 25- Langmuir, I. (1918). “The adsorption of gases on plane surfaces of glass, mica, and platinum.” J. Am. Chem. Soc., 40, 1361-1403. 26- Freundlich, H. Z. (1906a). “Over the adsorption in solution.” J. Phys. Chem., 57, 385-470. 27- Ho, Y. S., and Chiang, C. C. (2001). “Sorption studies of acid dye by mixed sorbents.” Adsorption, 37, 156162. 28- Ko, D. C. K., Porter, J. F., and McKay, G. (2000). “Optimised correlations for the fixed bed adsorption of metal ions on bone char.” Chem. Eng. Sci., 55, 5819-5829. 29- Goel, J., Kadirvelu, K., Rajagopal, C., and Garg, V. K. (2005). “Removal of lead (II) by adsorption using treated granular activated carbon: Batch and column studies.” J. Hazard. Mater., 125, 211-220. 30-Han, R., Ding, R., Xu, Y., Zou, W., Wang, Y., and Li, Y. (2008). “Use of rice husk for the adsorption of congo red from aqueous solution in column mode.” Bioresurce Technol., 99, 2938-2946. 31- Han, R., Wang, Y., Yu, W., Zou, W., Jie, S., and Liu, H. (2007). “Biosorption of methylene blue fron aqueous solution by rice husk in a fixed bed column.” J. Hazard. Mater., 141, 713-718. 32- Padmesh, T. V, N., Vijayaraghavan, K., Sekaran, G., and Velan, M. (2005). “Batch and column studies on biosorption of acid dyes on feresh water macro agga Azolla filiculoides.” J. Hazard. Mater., 125, 121-129. 33- Al-Degsa, Y. D., Khraisheh, M. A. M., Allen, S. J., and Ahmad, M. N. (2008). “Adsorption characteristics of reactive dyes in columns of activated carbon.”J. Hazard. Mater., 165, 944-949.
34
