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Selective adsorption of organic homologues onto activated carbon from dilute aqueous solutions: Solvophobic interaction approach: Part IV. Effect of simple structural modifications with aliphatics
Author(s) -
Belfort Georges,
Altshuler G. L.,
Thallam K. K.,
Feerick Jr C. P.,
Woodfield K. L.
Publication year - 1984
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690300205
Subject(s) - solvophobic , adsorption , chemistry , homologous series , aqueous solution , activated carbon , thermodynamics , molecule , organic chemistry , physics
Preferential adsorption of organic compounds onto activated carbon from dilute aqueous solutions is studied to develop a comprehensive theoretical basis for predicting the adsorption of structurally different isomers for different homologous series. The fundamental multidimensional approachof the solvophobic ( c ϕ) thermodynamic theory is further refined and used to correlate the extent of adsorption for the comprehensive theory with the overall standard net free energy change (Δ G net / RT ) for the association‐adsorption reaction in solution, and for the simplified theory with the cavity surface area of the solute ( TSA ). Experimental adsorption isotherms of two homologous series (12 aliphatic alcohols and 21 aliphatic ketones) were measured and used to test and compare the c ϕ theory with seven independent parameters characterizing the sorbates. Several experimental innovations for measuring equilibrium adsorption isotherms are introduced to reduce the possible loss of sorbate during the procedure and to provide reproducible and reliable results. Comparing the coefficients of linear correlation ( r ), the results for 12 aliphatic alcohols give greater than 99% confidence that the r ‐values are different for Δ G net / RT and molecular weight ( MW ). For the 15 aliphatic ketones, greater than 90% confidence interval is obtained for different r ‐values for TSA and MW . These results support the contention that simple structural modifications of aliphatic homologous compounds can be used to predict the effect of solute‐solvent‐sorbent interactions on adsorption. The c ϕ theory can thus be used to rank‐order adsorption intensity of these compounds from the aqueous phase onto activated carbon.