Supporting Information. Adsorption of Aromatic Chemicals by Carbonaceous Adsorbents: A

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1 Supporting Information Adsorption of Aromatic Chemicals by Carbonaceous Adsorbents: A Comparative Study on Granular Activated Carbon, Activated Carbon Fiber and Carbon Nanotubes Shujuan Zhang, Ting Shao, H. Selcen Kose, Tanju Karanfil* Department of Environmental Engineering and Earth Sciences Clemson University, Anderson, SC Environmental Science & Technology Submitted: March 8, 20 Revised: June 24, 20 *Corresponding author. tkaranf@clemson.edu, phone , fax This supporting information contains pages, 7 figures, and 2 tables. S

2 Quantity Adsorbed (mmol/g) Nitrogen ACF -HT Relative Pressure (P/P 0 ) Quantity Adsorbed (mmol/g) Water Vapor ACF -HT Relative Pressure (P/P 0 ) Figure S. Nitrogen and water vapor adsorption isotherms of the CNTs, GAC, and ACF. solid symbol : adsorption branch, open symbol : desorption branch. S2

3 ACF_PNT _PNT 0 0 L 0 00 L _PNT 0 _PNT 0 L L 0 00 Figure S2. Measured and predicted adsorption isotherms of PNT on the CNTs, GAC, and ACF. Dots: experimental data, lines: nonlinear fit with the four models. S3

4 ACF_BP _BP 0 0 L L _BP 0 _BP 0 L L Figure S3. Measured and predicted adsorption isotherms of BP on the CNTs, GAC, and ACF. Dots: experimental data, lines: nonlinear fit with the four models. S4

5 ACF_2PP _2PP 0 0 L L _2PP 0 _2PP 0 L L Figure S4. Measured and predicted adsorption isotherms of 2PP on the CNTs, GAC, and ACF. Dots: experimental data, lines: nonlinear fit with the four models. S5

6 ACF_PNT ACF_BP 0 0 _nonlinear _linear 0 00 _nonlinear _linear _PNT _BP 0 0 _nonlinear _linear _nonlinear _linear Figure S5. Measured and predicted adsorption isotherms of AOCs on ACF and. Dots: experimental data, solid line: linear fit with, dashed line: nonlinear fit with. S6

7 PNT 0 ACF -HT BP 0 ACF PP 0 ACF -HT Figure S6. Adsorption isotherms of AOCs on the CNTs, GAC, and ACF. Symbols: experimental data, lines: linear fit with. S7

8 V AOC (ml/g) linear fit V (r 2 SOC =.52*V N2 = 0.974, N = 8) PNT BP -HT ACF V N2 (ml/g) K FS (mg/g) linear fit K (r 2 FS = 0.60*S BET = 0.965, N = 8) PNT BP -HT ACF S BET (m 2 /g) q m (mg/g) Linear Fit q (r 2 m = 0.37*S BET = 0.702, N = ) PNT BP 2PP ACF 0 -HT S BET (m 2 /g) Figure S7. Structural parameters of the CNTs, GAC, and ACF vs adsorbed amounts of AOCs. The circled data points were excluded from linear fitting. S8

9 Table S. Nonlinear Adsorption Isotherm Models Model a Abbrev Equation Term b Freundlich qe = KFCe Langmuir Langmuir- Freundlich L q q n q K C K F [(mg/g)/(µg/l) n ]: adsorption affinity coefficient n: nonlinear index m L e e = K + KLC L (L/µg): adsorption affinity coefficient e e q K C K S [(L/µg) n ]: adsorption affinity coefficient = + n: nonlinear index n m S e n KSCe s Polanyi-Manes b a ε V qe = qm [ ( / ) ] ε = RT ln(s w /C e ) [kj/mol]: adsorption potential V s (cm 3 /mol): molar volume of solute a and b: fitting parameters a The is an empirical equation based on adsorption onto heterogeneous surfaces, which may be applied to a narrow or wide range of C e depending on the adsorbent-adsorbate system. The K F is a unitcapacity parameter, of equal value to the adsorbed amount at a value of C e equal to unity in given concentration units. The dimensionless n is related to the surface heterogeneity, whose value ranges between 0 and. The more homogeneous the surface, the closer n value is to. The basic idea behind the is the coverage of the surface by a monolayer. One of the main assumptions used is that all adsorption sites are equally "active". The L is an incorporated form of the and, which converts to the as n = and to the at low solute concentrations (K S C e n << ). An assumption of the model is that the adsorption is controlled by nonspecific dispersive interactions. As a consequence, it may be inapplicable to predict the adsorption involving specific interactions, such as formation of hydrogen bond and electron donor-acceptor complexes between adsorbates and oxygen-containing functional groups of adsorbents. b : equilibrium concentration of solute in adsorbent; q m (mg/g): maximum adsorption capacity; : equilibrium concentration of solute in solution; S w (µg/l): water solubility of solute. Isotherm modeling was directly performed in nonlinear form of all the four models, as listed in the table. Residual root mean square error (RMSE, as defined in Equation S) and coefficient of determination (r 2 ) were used to evaluate the goodness of fit. RMSE = ( ) N 2 qe,exp qe,fit (S) m i = where N is the number of experimental data points, m is the degree of freedom (m = N 2 for the twoparameter and ; m = N 3 for the three-parameter L and, q e,exp and q e,fit are experimental and fitted q e. S9

10 Table S2. Nonlinear fits of adsorption isotherms of AOCs on the CNTs, GAC, and ACF. Langmuir Freundlich Langmuir-Freundlich Polanyi-Manes ACF PNT BP 2PP PNT BP 2PP PNT BP 2PP PNT BP 2PP q m K FS q m q m 48 ± ± ± 55 K L K F K S a -6 ± ± ± 58 n n b.79 ± ± ± 0.32 r r r r RMSE RMSE RMSE RMSE N N N N q m K FS q m q m 23 ± 5 82 ± ± 7 K L K F K S a ± ± ± 55.6 n n b.67 ± ± ± 0.40 r r r r RMSE RMSE RMSE RMSE N N N N q m K FS q m q m 93 ± ± 3 94 ± 2 K L K F K S a ± ± ±.2 n n b.58 ± ± ± 0.03 r r r r RMSE RMSE RMSE RMSE N N N N q m K FS q m q m 58 ± ± ± 0.3E6 K L K F K S a -8.6 ±.9-9. ± ± 3.4 n n b.0 ± ± ± 0.43 r r r r RMSE RMSE RMSE RMSE N N N N HT q m 97 7 K FS q m q m 96 ± 93 ± 4 K L K F K S a ± ± 2. n n b.44 ± ± 0.04 r r r r RMSE RMSE RMSE RMSE N 8 8 N 8 8 N 8 8 N 8 8 S