مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Adsorption of Thymol From Aqueous Solution Using Granulated Su rfactant Initiated Modified Bentonite via Packed Column Method M. H. Abdul Latif, A. K. Mahmood and M. A. Al - Abayaji Departme nt of Chemistry, Ibn Al Haitham College of Education, Unive rsity of Baghdad Received in : 16 June 2011 Accepte d in :18 October 2011 Abstract The adsorpt ion study of thy mol, was carried out at (25±0.1) °C, using gr anulated surfa ctant modified Iraqi Na – montmorillonite clay (initiated modified bentonite); in a down-flow p acked column, the modif ied mineral was characterized by FT -IR sp ectroscopy . A linear calibr ation graph for thy mol was obtained, which obey Beer's law in the concentration range of 5-50 mg/L at 274 nm against reagent blank. Single-factor-at-a-time app roach; showed that the equilibrium time required for comp lete adsorp tion was 45 minute with flow rate (4.0drop/ mint). The adsorp tion of thy mol increased with rising p H of the adsorbate solution, increase of solute up take when the initial adsorbate concentration is increased. The adsorp tion is mostly p hysically in nature and fitt ed with Langmuir model. The result indicated that the p seudo-second-order kinetic models is fitt ed very well with the exp erimental data. Keywords : adsorp tion, thy mol, Na – montmorillonite, clay , p acked column. Introduction Phenolic comp ounds are the most imp ortant contaminants p resent in the environment. It can be originated naturally due to the degradation of humic substances, tannins, lignins and many of environment p rocesses, These comp ounds are used in several industrial processes to manufacture chemicals such as p esticides, exp losives, drugs and dy es. They are also used in the bleaching p rocess of p aper manufacturing. Ap art from these sources, p henolic comp ounds have substantial app lications in agriculture as herbicides, insecticides and fungicides [1, 2]. Thy mol (Scheme1) is p henolic monoterp ene, isolated from Thymus vulgaris, Origanum vulgare, Satureja thymbra and Thymbra capitata p lants [3] , confers antimicrobial prop erties to these oils. In addition, this p henolic comp ound is currently used in conjunction with chlorhexidine to inhibit oral bacteria. It has been p ost ulated that thy mol decreases enzy me activity and/or disrup ts membrane integrity by altering p rotein reactions [4]. Studies have shown that thy mol inhibits Gram-positive and Gram-negative bacteria and p ossess multiple biological p rop erties such as anti-inflammatory , anti-leishmanial, antioxidant [5], hepatop rotective and anti-tumor activities [6]. It have been shown to be an efficient acaricide molecule against the Varroa destructor, an external p arasitic mite that att acks honey bees [7]. M any methods are used for determination of thy mol such as liquid chromatographic methods by making a comp arison between the use of a silica-based monolithic column and a RP- Amide C16 column for the sep aration of p henol, thy mol and carvacrol [8], NM R [9] and HPTLC [10]. مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 CH3 H3C CH3 OH S cheme 1: The chemical structure of thymol Clay s are hy drated alumino si licates, comp osed of mixture of f ine- grained minerals, crystals of ot her miner als and oxides. Natural mineral clays p ossess sp ecific surface chemical p rop erties, e.g., cation exchange capacity , and adsorptive affinity for some or ganic and inorganic comp ounds, which have led to invest igate on the p otential use of clay s as adsorbents for treating heavy metals and or ganic p ollutants, or as coagulant aids for imp roving the settling p erformance in coagu lating low p article content water. By rep lacin g the natural inorganic exchan ge cations with alkyl ammon ium ions, clay surfaces are converted from being p rimarily hy drop hilic to hy drop hobic, which enable them t o interact st rongly with organic vapors and organic comp ounds dissolved in water [11]. Clay s obtaining montmorillonite are referr ed to bentonite which belon gs to the 2:1 clay family comp osed of two tetrahedrally coordinated sheet of silicon surroundin g an octahedrally coordinated sheet of aluminum ions [12].While the number of Al ions in tetrahedral sites determin es the net negative charge of the host lay er, which can adopt a number of interesting st acking arran gements to form ordered, p artially ordered, or disordered three-dimensional st ructures. Anot her interesting feature of clay is swelling [13], indicatin g that t he interlay er of some clay can reversibly incorp orate amounts of p olar molecu les, such as water and cations. M uch att ention has been drawn to the modification of clay mineral prop erties, because it has low cost and readily available in several technological app lications [14]. Clay s can be modified to increase the att enuation of some organic comp ounds and imp rove its sorp tion ability . Since hy dration of exchangeable alkali and alkaline earth metal cations creates a hy drop hilic environment on the surface and in the interlay er region of natural clays[15]. T he adsorbent p rop erties can be imp roved by replacing the natural inorganic cations with organic cations such as quaternary ammonium cations of the (CH3)3N + (CH2)15CH3 form. The main p urp ose of such modification is to increase the hydrop hobic nature of the mineral surface and consequently enhance the affinity towards organic comp ounds. Organo clays show different hy drop hobic p rop erties depending on the organic cations st ructure and its up take into the gallery . This is an imp ortant feature because the treatment of the mineral can be adjust ed according to need [16]. Anot her very imp ortant att ribute when clay modification is p rop osed for organo clay is the cation exchange cap acity (CEC). Vermiculite and bentonite are clay minerals with high CEC. The CEC for vermiculite, for inst ance, is ap p roximately 100– 150 meq p er 100 g [15]. West Iraqi (Traifawi) bentonite consists most ly of calcium – montmorillonite. The p ercent of montmorillonite is between (60 – 65 %) of crude bentonite, table (1) shows the chemical analysis of West Iraqi (Traifawi) bentonite, therefore it is necessary to remove the imp urities before the bentonite is ready to use. مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Apparatus A Cintra 5 sp ectrop hotometer with 1 cm quartz cells was used for absorbance measurements. Sartorius BL 210S (±0.0001 g)scientific balance, scientific shaker with thermal control(GCA p recision), pH-meter DW-9421 from Philip s inst rument, a glass co lumn (70 cm X 15 mm i.d.) and Pentium 4 co mputer (DELL 1545) was used for data p rocessing. Experime ntal Material and Reagents All Chemicals used wer e of analy tical reagent gr ad unless otherwise is mentioned, bentonite mineral clay obtained fro m the General Co mpany for Geological Surv ey and M ining in Baghdad; Iraq, thy mol crystal (Riedel- De Ha en). S tandard sol uti on Thy mol st ock solution (250 mg/L ), was p repared by dissolving 0.025 gm of thy mol in 5ml ethanol and diluting to 100 ml in volumetric f lask with distilled water. Working solutions were freshly p rep ared by subsequent dilutions. General Recommended procedure for determination of thymol 1 ml aliquots of thy mol st andard solution containing (25-250 mg/L) were t ransferred into a series of 5 ml volumetric flask; and diluted with distilled water. M easure the sp ectrum at 274nm against a reagent blank prepared similarly without addition of thy mol. Procedure for synthe sis of granulated surfactant modified Iraqi Na – montmorillonite clay a. Ini tiation In this st udy the bentonite was beneficiated to imp rove its Smectite (M ontmorillonite) content by att rition – scrubbing at high solid concentration (50%) and at high imp eller sp eed (2500 r.p .m.) for 1 h, using flotation cell. Then is converted calcium - montmorillonite to sodium - montmorillonite by p rocess of activation using ion-exchange technique, by mixing the bentonite p reconcentrate with Na – form activated amberlight orange ion exchanger followed by agitation for 1 h, at 150 r.p .m[17]. The clay was sep arated from the mixture by filtration, washed about five times with distilled water. Each washing st ep involved st irring the slurry in distilled water, followed by centrifugation and removal of the sup ernant, then Na – monmorillonite was treated with 0.5 M NaCl to ensure comp lete transformation to the Na – form , then the treated clay was washed with distilled water to remove excess NaCl[17] . b. Modification Then the sodium-form montmorillonite was modified with a surfactant Hexadecyltrimethy l ammonium bromide (HDTM A) to form organic modified clay ready to use in our research, it was done by adding (50 m mol/L) solution of (HDTM A) TO A 7% aqueous clay susp ension. The mixture was st irred in a mixer for 3h, at 350 r.p .m. The organic modified clay was sep arated from the mixture by filtration and washed about five times with distilled water[18]. مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 c. Granulation The organic modified montmorillonite turned to a granules of (2mm) diameter using granulating machine (GK Dry Granulating M achine) and dried at 110 ºC for 3h, until constant mass, to make an ion – exchange column ready to adsorb thy mol from aqueous solution. The surface area of 5 gm mass of adsorbent was calculated p hy sically and it equals to (75.09cm 2 ). Adsor ption Ex perime nts A glass column (70 cm X 15 mm i.d.) filled with known mass (5 gm) of adsorbent (modified or ganic Na – montmorillonite)corresp onding to bed heights of 3cm, percolated with 5 ml of (5-50 mg/L) thy mol solution adjust ed to different p H values 2.5, 5.5 and 10.8 (optimum 5.5) by ~ 0.1 N NaOH or ~ 0.1 N HCl, and different contact t ime ( from 5 to 120 minutes) with flow rate (4.0drop / mint).T he equilibr ium adsorp tion uptake (qe mg/g) and p ercentage remov al of thy mol from the aqueous solution was determined or calcu lated usin g the following r elationship [19]. Amount adsorbed qe = ( C0-Ce )V/W (mg of adsorbate / g of adsorbent) % removal = 100( C0-Ce )/ Ce Where C0 is the initial sorbate concentration (mg/L), Ce the equilibrium sorbate concentration(mg/L), V is the volume of solution in L and w is the mass of the adsorbent in (g). Results and Discussion Characteriz ation of clay Natural Iraqi bentonite FT IR sp ectrum[20] showed adsorp tion band at 3628.10 cm -1 (Al-Al-OH)(M g-OH-Al) corresp onding to st reching vibration of st ructural OH group s coordinating to Al-Al p air or M g-OH-Al fig.(1). Adsorbed water gives broad bands from 3406.29 cm -1 to 3533.59cm -1 corresp onding to H2O- st retching vibration . Al, M g bound water molecules gives H-O-H st retching vibration bond at 1643cm -1 . Also three bands at 1546.91, 1427.32 and 1384.89 cm -1 corresp onding to H..O..H weak . The complex broad band around 1033 cm -1 belongs to Si-O st retching vibration . Two bands at 914.26 cm -1 and 837.11 cm -1 are most characterist ic for quartz . Finally the bands from 420.00 cm -1 to 516.93 cm-1 are related to Al-O-Si , Si-O-Si deformations. Initiated bentonite FT IR sp ectrum fig.(2) showed the same bands of fig.(1) but with higher transmittance p ercent and sharp er than bands of FT IR sp ectrum of natural bentonite. Nevertheless H..O..H weak disapp ear in this sp ectrum. Adsorbed water band app ear at 3421.72 cm -1 ,two bands belong to Al, M g bound water molecules observed at 1654.92 cm -1 and 1641.42 cm -1 . The broad comp lex band becomes single band at 1039 cm -1 belongs to Si- O st retching vibration. Also we observe two bands belongs t o Al…OH st retching vibration at 937.04 cm -1 and 916.19 cm -1 with higher transmittance p ercent .The quartz characterist ics band from 694.37 cm -1 to 839.03 cm -1 become boarder. Finally Al-O-Si , Si-O-Si and Si-O st retching vibration bands from 426.27 cm -1 to 522.71 cm -1 become sharp er and triplet bond[18] Hexadecy l trimethy l ammonium bromide modified Iraqi bentonite FT IR sp ectrum (Figure 3) showed two adsorpt ion bands, t he first at 2927.94 cm -1 corresp onding to C – H of (- CH2) group s assy metric stretching vibration, and the second at 2854.65corresp onding to C – H of (- CH3) group s stretching for tetrahedral carbon[18]. مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Also we see an adsorption band at 1475.54 cm -1 corresp onding to C – H bending of (- CH3) group s, and a band at 1456.26 cm -1 corresp onding to C – H scisserin g in (- CH2) group s. C – N stretching adsorp tion band of quaternary aliphatic amine daesnt appear due to low force constant of this C – N bond of 4 O aliphatic amine. The adsorpt ion sp ectrum of thy mol adsorbed on in itiated modif ied Ir aqi b entonite fig.(4), showed a band at 3545.16 cm -1 corresp onding to O – H stretching free sharp band. Also t wo bands at 1643.35 cm -1 and 1475 cm -1 corresp onding to C – C aromatic st retching. Anot her band appears at 1311.59 cm -1 corresp onding to C – O stretching of thy mol . Out of p lane bendin g C – H bands ap p ears at 939.33 cm -1 . Absor ption spectrum Fig.(5) shows the absorption sp ectrum of (25 mg/L) thy mol against the reagent blank (distilled water), the maximu m absorp tion wavelengths at 274nm. Calibration graph Emp loying the exp erimental conditions, linear calibration graph for thy mol were obtained fig. (6), which show that Beer's law obey in the concentration range of (5-50 mg/L),The regr ession equations, correlation coeff icients, molar absorp tivities, and sandell sensitivities in addition to ot her p arameters are given in table (2). Effect of time of adsorption(contact time) In order to establish the equilibrium time for adsop tion, the effect of contact time was st udied table (3) shows the results for the effect of contact time on the removal of thy mol from aqueous solution at an initial concentration of 25 mg/l. about 52.040 %of thy mol had been remov ed within the first fifteen minutes of adsorpt ion and 67.876% within thirty minutes of adsorption. This is as a result, the adsorp tion cap acity generally increases with the increase in contact time until reaches the equilibriu m time of adsorp tion at 45 minutes with 77.072% had been removed. Effect of pH The pH of the thy mol solution will effect on the ability of adsorp tion, increases the pH of (25mg/ L ) thy mol solution from 2.5 to 5.5 leads to increase 3.5% of the % adsorbate removal, until when reaches to p H 10.8 leads to increase 4.1% of the % adsorbate removal, dissociation of thy mol into (C10H13O – ) will be repressed at p H > p Ka[18]; (p Ka value of thy mol is10.59 ± 0.10) [21] , resulting in high er rep ulsion between the p ositive surface char ge of the adsorbante and the anion. Effect of initial concentration The influences of thy mol concentration on the adsorption activity are illustrated, This means that an increase in initial adsorbate concentration resulted in increasin g of solute uptake fig.(7). The initial solute concentrations p rovide an imp ortant driving force to overcome all mass transfer resistance of adsorbate between aqueous and sol id p hase, the high er initial solute concentration will decrease the mass transfer resist ance. Hence, high er in itial concentration of adsorbate enhances adsorp tion process with the result of higher interaction between solute and the adsorbent[22,23]. Adsor ption i sotherm The equilibrium adsorp tion isotherm is imp ortant in the design of adsorption sy stems. Because it's useful to describe how solutes interact with adsorbents and very imp ortant to evaluate the feasib ility of the adsorbate-adsorbent system. The set of exp erimental results as مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 p resented in (Figur e 8) at room temp erature (25±0.1) was fitt ed with the Freundlich and Lan gmuir model. Adsorp tion isot herms were obtained and the adsorp tive cap acity interp reted using both models. Freundlich isothe rm The Freundlich exp ression [23] is an empirical equation d escribing sorp tion onto heterogeneous surface. The isotherm assumes that the surface sites of the adsorbent have a sp ectrum of different bindin g ener gies. The linear equation is p resented as: log qe = log kF + 1/n log C0 where KF is The Freundlich constant (L/g) and 1/n is the adsorp tion intensity . The value of n indicates the favorable adsorp tion ability . , the values of log KF and 1/n can be calculated from the intercep t and the slop e of the linear p lot of log qe versus log Ce fig.(9). Langmuir isotherm The Lan gmuir model [24] is widely used for modeling equilibriu m data. The isotherm is valid for monolayer adsorp tion onto a surface containin g a finite number of identical sites. It can be descr ibed by the linear form: 1/qe=1/qmax+1/q maxKL ٠1/Ce where qm ax is the adsorp tion cap acity at saturation (mg/g) and KL (L/mg) is the adsorption coefficient related to ener gy of adsorption, the values of qm ax and KL can be evaluated fro m the intercept and the slope of the linear plot of exp ermantal data of 1/qe versus 1/Ce fig.(10). The Langmuir isot herm can also be exp ressed by a sep aration factor [25], which is given by the equation . RL = 1/ (1 + KL٠ C0) Where, ‘C0’ is the initial concentration of thy mol in mg/L and ‘KL’ is the Langmuir constant in g/L. The sep aration factor ‘RL’ indicates the nature of the adsorption process[26] as given in (Table 4). The results reveal that the adsorp tion of thy mol was best fitting with Lan gmuir model rather than Freundlich table(5), as indicated by higher R 2 v alues, the low value of the Freunlich constant (kF = 0.001 L/g), whi ch indicates the effectiveness of the thy mol- Na – montmorillonite clay system and the value of adsorp tion intensity , ‘n’ is found to be 0.633 did not satisfy the condition of heterogeneity , i.e., 1< n < 10 as well as 0 < 1/n < 1 [27]. While the high er magnitude of ‘qm ax’ (0.170 mg/g) for Lan gmuir mode indicates that the amount of thy mol p er unit weight of sorbent (to form a co mplete monolay er on the surface) seems t o b e significantly high er, also a relatively lower ‘KL’ value (0.018 L/mg) imp lies low surface ener gy (KL < 0.3), thus indicating a p robable st ronger bonding between thy mol and sorbents [28]. Adsor ption kinetics Kinetic models are used to examine the rate of the adsorp tion process in the present work, the kinetic data obtained from t he studies have been analyzed by using p seudo-first-order and p seudo-second-order models. The pseudo first order equation of Lagergren is generally exp ressed as follows[29]. dq/dt=k1(qe-qt) مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 where qe is the amount of thy mol adsorbed at equilibrium (mg/g), qt is the amount of thy mol adsorbed at time t (min -1 ), and k1 is the rate constant of p seudo-first-order adsorption. If it supp osed that q=0 at t=0, then: ln (qe-qt)= lnq- k1t The pseudo-second-order kinetic rate equ ation is exp ressed as follows [30]. dqt/dt=k2(qe-qt) 2 Where k 2 is the rate constant of p seudo-second-order sorpt ion (g/mg/min). The inte grated form of equation when (t=0 →t and qt=0→ 0qe) the following exp ression is obtained: t/qt=1/k2qe 2 + t/qe The rate const ant k1, k2 and qe calculated from the slop es and intercepts of t he linear plot of ln(qe-qt) or (t/qt ) against t resp ectively fig.(11and 12). It is seen that thy mol removal well described by the p sudo second order reaction kinetc. M oreover, the correlation coefficient (R 2 ), of p seudo-second-order reaction kinetic(0.991) is higher than that of the p seudo-first- order reaction kinetic(0.989) and greater value of rate constant for the adsorp tion data. While the value of qe exp erimental is app roximately equal qe calculated for the both first and second order reaction kinetic; Table(6) shows the rate constants, qe (exp erimental , calculated ) and correlation co efficient (R 2 ) for p sudo first and second order reaction kin etc. Anal ysis of Thymol The concentration of residual thy mol (after adsorp tion) was determined sp ectrop hotometrically accordin g to the standard methods, at 274nm. Accura cy and precisi on The accuracies of the p rop osed methods were confirmed by analyzing three r eplicate analyses of four different amounts of thy mol ;within Beer 's law ( before and after adsorp tion) by calculating the relative error p ercentage. The results indicated good accuracies of the method. The p recision was determined by calcu lating the p ercentage relative st andard deviation (RSD %) for three determin ations at each of the st udied concentration level tables (7 and 8). Conclusion In this study , the adsorption of thy mol from aqueous solution was invest igated usin g granulated surfactant initiation modified bentonite. The results indicated that adsorption cap acity of the adsorbent was considerably affected by contact time, initial p H, and initial thy mol concentration. The results indicated that the up take of thy mol took p lace at a p H in the range of (2.5-10.8); the adsorp tion of thy mol increased with increase of p H. The result also showed that the amount of thy mol adsorbed incr eased the increase of initial thy mo concentration. The results reveal that the adsorption of thy mol obey s Langmuir adsorp tion isotherms. The pseudo-first and second-order kinetic models were used to analyze the data obtained for thy mol adsorp tion from aqueous solution. 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Ho, Y.S. and M ckay , G. (1999) Pseudo-second-order model for sorp tion p rocess. J. of Process Biochem. 34 (5): 451-465. مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Table (1): Chemical analysis West Iraqi (Traifawi) bentonite. Compound (wt, %) Iraqi (Traifawi) bentonite SiO2 55.81 Al2O3 14.91 Fe2O3 5.78 CaO 5.72 M gO 3.5 Na2O 1.29 K2O 0.41 LiO2 0.67 SO3 ---- L.I.O. 10.86 Total 98.95 Table (2): S pectral characteristi cs and statistical data of the regression equati ons for determination of thymol. Parameter Thymol λmax (nm) 274nm Col or colorless Line arity range (mg/L) 5-50 Molar absorpitivites (l.mol -1 .cm -1 ) 1922.816 Regression equati on A = 0.0128 [ Thy mol(mg/L)] + 0.0245 Calibration Se nsitivity 0.0128 S andell's Se nsi tivity (µg.cm -2 ) 78.125 Correl ation of Linearity (R 2 ) 0.9983 Correl ation coefficient (R) 0.9991 مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Table (3): Effect of contact time on the adsorption of (25mgl/L) thymol from aque ous solution. Ini tial Conc. (mg/L) Time (minute) Equi librium Conc. (Ce) (mg/L) % Removal qe (mg/g) Equi librium Time (minute) 5 16.156 35.376 0.0088 10 13.798 44.808 0.0112 15 11.990 52.040 0.0130 20 10.426 58.296 0.0146 30 8.031 67.876 0.0169 40 6.379 74.484 0.0186 45 5.714 77.072 0.0193 60 5.714 77.072 0.0193 75 5.714 77.072 0.0193 90 5.714 77.072 0.0193 25.000 120 5.714 77.072 0.0193 45 Table(4): The process nature of separation factor. S .No. RL Value Type of process 1 RL > 1 Unfavorable 2 RL = 1 Linear 3 0 < RL < 1 Favorable 4 RL = 0 Irreversible Table(5): Freundlich and Langmuir isotherm paramete rs for the adsorption of thymol at (25±0.1) ° C under optimum conditions. Freundlich isothe rm paramete rs Langmuir isotherm paramete rs KF (L/g) n R 2 qm ax (mg/g) KL (L/mg) R 2 RL * 0.001 0.633 0.988 0.170 0.018 0.990 0.526-0.917 * for (5-50 mg/L) initial concentration of thy mol . مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Table(6): The pse udo- first and second- kine tic order paramete rs for the adsorption of 25 (mg/L) of thymol at (25±0.1) ° C under optimum conditions. qe Expe. (mg/g) The pseudo-first-order kinetic models The pseudo-second-order kinetic models qe ca lc. (mg/g) K1 (min -1 ) R 2 qe ca lc. (mg/g) K2 (g/mg/min) R 2 0.0193 0.016 0.069 0.989 0.023 4.167 0.992 Table (7): Evaluati on of accuracies and precisi ons for thymol before adsorption. *Average of three determination s. Table (8): Evaluati on of accuracies and precisi ons for thymol after adsorption at optimum conditi ons. Concentration (mg/L) Take n Found(Co)* After Adsoption % Removal Relative Error* % R.S .D.* % 10 3.014 69.860 1.427 1.701 25 5.714 77.144 1.383 1.663 40 8.471 78.822 1.522 1.874 50 9.964 80.072 2.721 2.987 *Average of three determinations. Concentration ((mg/L) Take n Found* Before Adsoption Relative Error* % R.S .D.* % 10 9.897 1.030 1.212 25 24.775 0.900 1.158 40 39.572 1.070 1.371 50 48.878 2.244 2.816 مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Fig. (1): FTIR s pectrum for cru de Iraqi bentonite (Trifawi). Fig. (2): FTIR s pectrum for ini tiated Iraqi bentonite (Trifawi). Fig. (3): FTIR s pectrum for ini tiated modified Iraqi bentonite (Trifawi). مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Fig. (4): FTIR s pectrum for thymol adsorbed on i ni tiated modified Iraqi bentonite. Fig. (5): Absor ption spectrum of (25mg/L) thymol , against reagent blank (distal water). مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Fig. (6): Calibration curve for thymol Fig.(7): Effect of ini tial against reagent blank(distilled water) concentration onto adsorption at 274nm. of (10, 25 and40)mg/L of thymol sol ution Fig.(8):Adsor ption i sothe rm for Fig.(9):Freundli ch isothe rm for thymol at(25±0.1) ° C under the adsorption of thymol optimum conditi ons. at(25±0.1) ° C under optimum conditi ons. مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Fi g.(10 ): Langmui r i sothe rm fo r the Fig.(11): The pseudo -fi rst- orde ki neti c a dsorption of thym ol at(25±0.1) ° C models for the adsorpti on of unde r optimum con diti ons. 25(mg/L)th ymol at(25±2) ° C u n der optimum condi tion s. Fig.(12): The pseudo-second-order kinetic models for the adsorption of 25 (mg/ L) of thymol at (25±0.1) ° C under optimum conditions. مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 امتزازالثایمول من محلوله المائي بأستعمال طین البنتونایت المنشط والمحورعضویآ بطریقة العمود المعبأ محمد حسن عبد اللطیف، علي خلیل محمود ، مھا عبد الحمید العبایجي قسم الكیمیاء، كلیة التربیة ابن الھیثم، جامعة بغداد 2011 تشرین األول 18: قبل البحث في 2011 حزیران 16: استلم البحث في الخالصة ط المعغرفة، بأست اجریت دراسة ألمتزاز الثایمول من محلوله المائي بدرجة حرارة ال طین البنتونایت العراقي المنش ط . ت طریقة العمود في عملیة االمتزازلمع استاذ المونتموریلونایت والمحور عضویآ، أةعلى هی شخص البنتونایت المنش كما تم الحصول على منحني تدریجي خطي ه وبعد والمحور بأستخدام طیف االشعة تحت الحمراء، قبل امتزاز الثایمول وعند الطول الموجي ، لتر/ ملي غرام) 50-5(لول الثایمول وبمطاوعة لقانون المبرت بیر لمدى من التراكیز یتراوح بینلمح ة الزم لحصول وجد ان الزمن ااذ المتغیرات المؤثرة في عملیة االمتزاز، تدرس. نانو متر، ضد محلول الخلب274 ل عملی p)( زیادة في امتزاز المحلول بزیادة الدالة الحامضیة حظولو. قطرات لكل دقیقة4 دقیقة، وبسرعة جریان 45االتزان هو H ا فيشكل فیزیائي وكما وجد ان طبیعةعملیة االمتزاز ذ. اوبزیادة التركیز االبتدائي للمادة الممتزة، االغلب، وینطبق علیه . وأظهرت النتائج ان عملیة األمتزاز تتبع تمامآ حركیة المرتبة الثانیة الكاذبة. زایزوثیرم النكمایر لالمزا مونتموریلونایت، طین، طریقةالعمود - امتزاز، ثایمول، صودیوم :الكلمات المفتاحیة مجلة إبن الھیثم للعلوم الصرفة و التطبیقیة 2012 السنة 25 المجلد 1 العدد Ibn A l-Hai tham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012