Conseguences of soil crude oil pollution on some wood properties of olive trees Chemistry |150 https://doi.org/10.30526/30.3.1609 2012(عام 3العدد ) 30مجلة إبن الهيثم للعلوم الصرفة والتطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 30 (3) 2017 Adsorption of Tetracycline on the Bauxite and Modified Bauxite at Different Temperatures Israa M. Radhi Yousif I. Mohammed Takialdin A. Himdan Dhefaf H. Badri Dept. of Chemistry /College of Education for Pure Science) Ibn Al Haitham(/ University of Baghdad Received in:24/May/2017,Accepted in:28/May/2017 Abstract In this study, bauxite and modified bauxite /polymer, which were prepared as an adsorbent surfaces to adsorption of the tetracycline from aqueous solutions. A series of adsorption experiments were conducted to determine the equilibrium time and temperature effect on the adsorption process. The results showed that adsorption was agreed with the Freundlich equation model for the surface of the bauxite. As for the modified bauxite surface, the results were consistent with the Langmuir equation model. The values of the basic thermodynamic functions of the adsorption process were calculated, so the process of adsorption was founded spontaneous and endothermic. Key word: Bauxite, Modified bauxite, Adsorption, Tetracycline Chemistry |151 https://doi.org/10.30526/30.3.1609 2012(عام 3العدد ) 30مجلة إبن الهيثم للعلوم الصرفة والتطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 30 (3) 2017 Introduction Antibiotics are widely used in human therapy [1]. Tetracycline is a broad-spectrum antibiotic that works against grampositive and negative bacteria and inhibits their growth. Recently, tetracycline became a concern the trend to the environment[2]. It is detected through contaminated water from water treatment plants [3,4], so that the removing it has a great importance. The removal is done using certain adsorbents such as Montmorellonite [5] where this method is the easiest and the most economical. In this study, bauxite and modified bauxite were used as good adsorbents surfaces to adsorption of the tetracycline from aqueous solutions. Bauxite is the most important type of aluminum ores, it consists of gibbsite, boehmite and diaspore in large quantities, as well as less goethite and hematite and small amounts of anatase [6]. It was first discovered by French geologist Pierre Berthier in 1821[6]. Experimental part In this study, the following devices were used : 1-Double beam UV- visible spectrophotometer type Shimadzu. 1800, Japan. 2- A water bath shaker Labtech. Korea. 3- Balance (0.0001 g ±) type Sartorius Lab. BL 210 S, Germany. The chemicals were used (melamine from BDH, urea from Hannover, formaldehyde and hydrochloric acid from Reidel-De Haen). The Bauxite from the general company of geological survey in Iraq. The Tetracycline from SDI- Samarra. The modified bauxite has been prepared previously [7]. Effect of Contact Time The equilibrium time was determined at a temperature of 293K, taking 50 ml of the tetracycline solution at a concentration of 40ppm and adding it to 0.05g of both adsorbents which were shaken in the shaker water bath. The time period ranged from 10min-180 min, after every 10 minutes separate the solution using a centrifuge at 5000 rpm for 10 minutes. Then the solution was separated and analyzed using a spectrophotometer at the λmax=356 nm. The results indicated that the best time for equilibrium was 2 hours and 3 hours for bauxite and modified bauxite, respectively. Adsorption Isotherms A volume of 50 ml. of six different concentrations of tetracycline (20,30,40,50,60 and 70) ppm was shaken with 0.05 g of both adsorbents at acertain temperature in the shaker water bath. After the equilibrium time is elapsed, separate the solution using a centrifuge at 5000 rpm for 10 minutes. After the separation, the absorption of the solution was measured using a spectrophotometer at the λmax. Through absorption values, we can calculate the concentration at equilibrium using the calibration curve. Results and Discussion The amount of drug adsorbed at certain conditions of temperatures was calculated from equation: ( ) …….(1) Where, (V) is the volume of solution in litres, (C0) and (Ce) are the initial and equilibrium concentration of the drug in milligrams per litre. (M) is the weight of adsorbent which was taken equal to 0.05 g. [8] The extent of adsorption of tetracycline at (25,30,35,40 and 45) 0 C from aqueous solution on bauxite and modified bauxite is given in Figure (1)and (2). Chemistry |152 https://doi.org/10.30526/30.3.1609 2012(عام 3العدد ) 30مجلة إبن الهيثم للعلوم الصرفة والتطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 30 (3) 2017 In Figure (1), The general pattern of adsorption isotherm of the tetracycline on the surface of the bauxite follows the S2max pattern at low temperatures and then begins to convert to L2max pattern at high temperature. Figure (2) shows that the adsorption of the tetracycline on the modified bauxite surface follows the Lmax pattern at low temperatures and then changes to the Smax pattern at high temperatures (up to 318K). The maximum-adsorption occurs when the adsorbed particles reach a certain level of concentration, which begins by interfering strongly with each other in the solution to form agregations. These agregations increase the solubility of the adsorbent by increasing the concentration and thus decrease the adsorption potential of these molecules [9] .When the literatures were reviewed, it was found that tetracycline tends to form agregations by attracting different charges on the tetracycline molecules itself ,and that these agregations have less adsorption capability. This is due to decreased adsorption and the formation of the maximum end point in the isotherm curve[10,11]. There are several isotherm adsorption models that help to explain the obtained results for isotherm: Freundlich Isotherm Model The Isotherm Freundlich equation (2) [12]for tetracycline adsorption was applied to the bauxite and modified bauxite surface at different temperatures as shown in Figure(3) and (4). ln qe = ln kf + 1/n ln Ce ……..(2) where kf and n are Freundlich constants, qe the amount of drug adsorbed (mg/g) and Ce is the equilibrium concentration of tetracycline (mg/L). A plot of log qe against log Ce would give the values of n and kf from the slope and intercept respectively. The values of Freundlich constants with the correlation coefficients are shown in Table 1. The results shown in the table indicate that the values of the Freundlich constants at different temperatures on the surface of bauxite have an increase in the value of kf by increasing the temperature, while is fluctuate in value at different temperatures. As for the values of the Freundlich constants on the modified bauxite surface, we observe their variability at different temperatures. This indicates that bauxite corresponds to the model well while modified bauxite has a weak corresponds. Langmuir Isotherm Model The Isotherm Langmuir equation (3)[13]for tetracycline adsorption was applied to the bauxite and modified bauxite surface at different temperatures as shown in Figure(5) and (6). Ce/qe = 1/a k + Ce/a ……..(3) where k and a are Langmuir constants, qe the amount of drug adsorbed (mg/g) and Ce is the equilibrium concentration of tetracycline (mg/L). A plot of Ce/qe against Ce would give the values of a and k from the slope and intercept respectively. The values of Langmuir constants with the correlation coefficients are shown in Table 2. The results shown in the table indicate there is a fluctuation in the values of the equilibrium constant or the constant of the adsorption process according to Langmuir in the case of bauxite at different temperatures. In the case of modified bauxite, we observe negative values, which are mainly due to non-typical adsorption and then become positive when the temperature rises. As for the values of the maximum amount of absorbent matter calculated according to the Langmuir model of the bauxite modified bauxite surface, we note that there is a fluctuation of these values at low temperatures followed by a continuous increase at high temperatures. These results indicate that the modified bauxite corresponds to the model well, while bauxite is moderately consistent. Interpretation of thermodynamic functions The equilibrium constant (keq) for the adsorption process at each temperature is calculated from the equation (4): keq =qm/Ce ……..(4) Chemistry |153 https://doi.org/10.30526/30.3.1609 2012(عام 3العدد ) 30مجلة إبن الهيثم للعلوم الصرفة والتطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 30 (3) 2017 Where qm is the amount of maximum absorbent at equilibrium (mg/g) and Ce is the equilibrium concentration of tetracycline (mg/L). The change in free energy (∆G) could be determined from the equation (5): ∆G = -RTlnK ….(5) Where R is the gas constant (8.314 J.mol -1 .K -1 ) and T is the absolute temperature The heat of adsorption (∆H) may be obtained from the equation (6): ……..(6) Where k is the equilibrium constant. Table 3 gives k values at different temperatures. A plot of lnk versus 1/T would give a straight line with a slope = (-∆H/R) as shown in Figure (7) and (8). The change in entropies (∆S) was calculated from Gibbs equation (7): ∆G = ∆H-T∆S ……..(7) Table 4 shows the basic thermodynamic values of adsorption of the tetracycline on bauxite and modified bauxite. The values shown in the table indicate that the heat adsorption of tetracycline, whether on the surface of the bauxite or modified bauxite, is positive and this indicates that the adsorption process is andothemic process. This indicates to the possibility of a high absorption process associated with adsorption process and this result agrees with the results of the study[14]. We also note that the values of change in free energy are negative and this indicates that the process of adsorption is spontaneous. As for the values of the change in the entropy, it is positive and its value on the surface of the bauxite is higher than the modified bauxite surface. This is the reason for the possibility of forming the symmetric bond between the neoclophilic groups in the tetracycline molecule with empty orbitals that found in the aluminum atom on the surface of the bauxite. Its value on the modified bauxite surface is lower. This indicates that the formal structures taken by tetracycline molecules when trapped inside the polymer paths and pores are not significantly different from the probability of their arrangement in the aqueous solution. References 1 - Zhang, L. et al. (2011) “Studies on the removal of tetracycline by multi-walled carbon nanotubes”. Chem. Eng. J. 178, 26–33. 2 - Gao Y. et al. (2012) “Adsorption and removal of tetracycline antibiotics from aqueous solution by graphene oxide”. J. Colloid Interf. Sci. 368, 540–546. 3 – Beausse, J. (2004) “Selected drugs in solid matrices: a review of environmental determination, occurrence and properties of principal substances”. Trac-Trend Anal. Chem. 23, 753–761. 4 - Golet, E. M.; Strehler, A.; Alder, A. C. & Giger, W. (2002) “Determination of fluoroquinolone antibacterial agents in sewage sludge and sludge-treated soil using accelerated solvent extraction followed by solid-phase extraction”. Anal. Chem. 74, 5455– 5462. 5 – Parolo, M. E.; Avena, M. J.; Pettinari, G. R. & Baschini, M. T. (2012) “Influence of Ca 2+ on tetracycline adsorption on montmorillonite”. J. Colloid Interface Sci. 368, 420–426. 6 - Suman Pawar; Krishna Gurlhosur and Sreekanth B. (2015) “Removal of Lead by Adsorption with Bauxite in a Fluidized -Bed Operation”, International Journal of New Technologies in Science and Engineering. 2,. 1, ISSN 2349-0780. 7 – Israa, M. R. al-Fadhli ;Yousif, I. M. Abuzaid and Takialdin, A. Himdan, (2016) “Interactions Investigation of New Composite Material Formed from Bauxite and Melamine- Urea Formaldehyde Copolymer”, Ibn Al-Haitham Jour. For Pure &Appl. Sci., vol. 29 (1). 8 - Alla A. Ibrahim, ( 2016)“Adsorption study of Tetracycline on new prepared Attapulgite- Azo polymer complex”. Chemistry |154 https://doi.org/10.30526/30.3.1609 2012(عام 3العدد ) 30مجلة إبن الهيثم للعلوم الصرفة والتطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 30 (3) 2017 9 – Giles, C. H.; MacEwan, T. H.; Nakhwa, N. and Smith, D. (1960) „„Studies In Adsorption ,Part XI:A System Of Classification Of Solution Adsorption Isotherm Mechanisms And In Measurement Of Specific Surface Area Of Solids‟‟, J. Chem.Soc., 786:3973-3993. 10 - Siegfried Schneider; Matthias O. Schmitt, Georg Brehm, Markus Reiher, Pavel Matousek and Mike Towrie , (2003) "Fluorescence kinetics of aqueous solutions of tetracycline and its complexes with Mg 2+ and Ca 2+ ", Photochem. Photobiol. Sci., 2, 1107–1117. 11 - Kumar R.; Mohamed Kamil, M. G., Shri Prasad S., Gayathri G. S. and Shabeer T. K., (2013) "Ultrasonic and viscometric study of molecular interaction of antibiotic doxycycline hycalte", Indian Journal of Pure & Applied Physics, Vol. 51, pp. 701-707. 12 - Liangliang, J., S. Yun; Xu. Zhaoyi, Z. Shourong and Z. Dong qiang, (2010) “Adsorption of Monoaromatic Compounds and Pharmaceutical Antibiotics on Carbon Nano – tubes Activated by KOM Etching”, Sci. Technol. 44 (16), 6429 – 6436. 13 – Israa M. Radhi, (2015) “Physical Study of Bauxite and modified Bauxite Surfaces identification for tetracycline adsorption on them at different temperatures”. 14 – Hussein, H. K.; Jassim, S. M. and Isa, S. A., (2001) Sent for Publication. Table (1): Experimental Freundlich constants and correlation coefficient values for tetracycline adsorption on bauxite and modified bauxite/polymer surfaces 298 K 293 K Adsorbent R 2 n kf(L/mg) R 2 n kf(L/mg) 0.4753 1.339008 0.201857 0.562 1.418795 0.173421 Bauxite 0.1404 -6.37004 9.495273 0.3629 -2.50705 17.13394 Polymer 308 K 303 K Adsorbent R 2 n kf(L/mg) R 2 n kf(L/mg) 0.7775 2.013136 0.625257 0.5677 2.245408 0.681169 Bauxite 0.0024 -52.0096 4.219827 0.0003 -328.961 2.816479 Polymer 318 K 313 K Adsorbent R 2 n kf(L/mg) R 2 n kf(L/mg) 0.8115 2.002192 0.950128 0.863 1.626741 0.479041 Bauxite 0.1161 4.765777 2.814918 0.5465 3.318814 1.644996 Polymer Table (2): Experimental Langmuir constants and correlation coefficient values for tetracycline adsorption on bauxite and modified bauxite/polymer surfaces 298 K 293 K Adsorbent R 2 a(mg/g) k(L/mg) R 2 a (mg/g) k(L/mg) 0.2434 8610.754 0.015168 0.3394 6018.494 0.017015 Bauxite 0.8808 4194.708 -0.1248 0.8352 1816.136 -0.04119 Polymer 308 K 303 K Adsorbent R 2 a(mg/g) k(L/mg) R 2 a(mg/g) k(L/mg) 0.7839 7845.14 0.026525 0.6555 6602.84 0.029652 Bauxite 0.9214 3323.093 -0.12732 0.9534 2828.241 0.825802 Polymer 318 K 313 K Adsorbent R 2 a(mg/g) k(L/mg) R 2 a(mg/g) k(L/mg) 0.7769 12818.22 0.022848 0.8031 12579.92 0.01515 Bauxite 0.5995 7107.203 0.163886 0.9396 7134.041 0.065825 Polymer Chemistry |155 https://doi.org/10.30526/30.3.1609 2012(عام 3العدد ) 30مجلة إبن الهيثم للعلوم الصرفة والتطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 30 (3) 2017 Table (3): Constant equilibrium values at different temperatures for tetracycline adsorption on the bauxite and modified bauxite/polymer surfaces Ln k k 1/T K -1 T/K Adsorbents 4.09 60.09 0.0034 293 Bauxite 4.40 81.77 0.0034 298 4.37 78.89 0.0033 303 4.41 82.61 0.0032 308 4.56 95.98 0.0032 313 4.88 131.53 0.0031 318 4.25 69.84 0.0034 293 Polymer 4.65 104.38 0.0034 298 4.24 69.28 0.0033 303 4.88 131.45 0.0032 308 4.38 79.53 0.0032 313 4.89 133.88 0.0031 318 Table (4): Values of thermodynamic functions the adsorption of the tetracycline on the bauxite and modified bauxite/polymer surfaces Bauxite T (K) ∆S (J.mol -1 .K -1 ) ∆H (kJ.mol -1 ) ∆G (kJ.mol -1 ) 100.91 -9.97 293 102.35 -10.91 298 100.96 19.59 -11.00 303 100.30 -11.30 308 100.53 -11.87 313 102.16 -12.89 318 Modified bauxite T (K) ∆S (J.mol -1 .K -1 ) ∆H (kJ.mol -1 ) ∆G (kJ.mol -1 ) 81.74 -10.34 293 84.30 -11.52 298 80.14 13.61 -10.67 303 84.74 -12.49 308 79.85 -11.38 313 83.50 -12.95 318 Figure (1): Isotherm adsorption of tetracycline on the surface of bauxite 0 1 2 3 4 5 6 7 8 9 10 11 0 20 40 60 80 100 Q e (m g /g ) Ce(mg/L) 293 K 298 K 303 K 308 K 313 K 318 K Chemistry |156 https://doi.org/10.30526/30.3.1609 2012(عام 3العدد ) 30مجلة إبن الهيثم للعلوم الصرفة والتطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 30 (3) 2017 Figure (2): Isotherm adsorption of tetracycline on the surface of modified bauxite Figure (3): Isothermic Freundlich for tetracycline adsorption on the surface of bauxite Figure (4): Isothermic Freundlich for tetracycline adsorption on the surface of modified bauxite Figure (5): Isothermic Langmuir for tetracycline adsorption on the surface of bauxite 0 2 4 6 8 10 0 20 40 60 80 100 120 Q e (m g /g ) Ce(mg/L) 293 K 298 K 303 K 308 K 313 K 318 K 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 ln Q e lnCe 293 K 298 K 303 K 308 K 313 K 318 K 0 0.5 1 1.5 2 2.5 3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 ln Q e lnCe 293 K 298 K 303 K 308 K 313 K 0 0.01 0.02 0.03 0.04 0.000 20.000 40.000 60.000 80.000 100.000 C e /Q e Ce(mg/L) 293 K 298 K 303 K 308 K 313 K Chemistry |157 https://doi.org/10.30526/30.3.1609 2012(عام 3العدد ) 30مجلة إبن الهيثم للعلوم الصرفة والتطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 30 (3) 2017 Figure (6): Isothermic Langmuir for tetracycline adsorption on the surface of modified bauxite Figure (7): The Van Huff's curve for tetracycline adsorption on the surface of bauxite Figure (8): The Van Huff's curve for tetracycline adsorption on the surface of modified bauxite 0 0.01 0.02 0.03 0.04 0.05 0.06 0.000 20.000 40.000 60.000 80.000 100.000 120.000 C e /Q e Ce(mg/L) 20C 25C 30C 35C 40C 45C 4.000 4.200 4.400 4.600 4.800 5.000 0.0031 0.0032 0.0032 0.0033 0.0033 0.0034 0.0034 0.0035 ln K e 1/T K-1 4.200 4.400 4.600 4.800 5.000 0.0031 0.0032 0.0032 0.0033 0.0033 0.0034 0.0034 0.0035 ln K e 1/T K-1