Adsorption Isotherms of Phenol and 4-Chlorophenol on Petroleum Asphaltenes

Abstract

Les isothermes d'adsorption du phŽnol et du 4-chlorophŽnol en solution dans l'eau sur des asphalt•nes floculŽs en masse et sur des asphalt•nes dŽposŽs sur de la silice ont ŽtŽ dŽterminŽs par analyse chromatographique frontale ˆ 293, 298, 303 et 308 K. L'adsorption sur des asphalt•nes floculŽs en masse Žtait la plus importante avec des isothermes correspondant ˆ un mŽcanisme de Freundlich. La quantitŽ ŽlevŽe de phŽnols adsorbŽs sugg•re une migration possible des molŽcules du phŽnol ˆ travers la structure peu compacte des asphalt•nes. Les isothermes observŽs dans le cas de silice tapissŽe d'asphalt•nes ont montrŽ que l'adsorption se produit en deux Žtapes correspondant probablement ˆ deux organisations diffŽrentes des molŽcules de solutŽ ˆ la surface. ADSORPTION ISOTHERMS OF PHENOL AND 4-CHLOROPHENOL ON PETROLEUM ASPHALTENESThe adsorption isotherms for phenol and 4-chlorophenol from water onto asphaltenes flocculated in bulk and asphaltenes deposited on silica were established by frontal analysis chromatography at 293, 298, 303, and 308 K. The adsorption was more important with asphaltenes flocculated in bulk and corresponded to a Freundlich isotherm mechanism. The high adsorbed amount of phenols suggests possible migration of phenols through the loose asphaltene structure. Isotherms observed with the silica coated by asphaltenes showed that adsorption occurs in two stages corresponding probably to two different organizations of solute molecules at the surface. ADSORCIîN DEL FENOL Y DEL 4-CLOROFENOL EN LOS ASFALTENOS PETROLEROSLos isotermos de adsorci-n del fenol y del 4-clorofenol en soluci-n en el agua respecto a los asfaltenos floculados en masa y, asimismo, en los asfaltenos depositados sobre s'lice, se han determinado por an ‡lisis cromatogr ‡fico frontal a 293, 298, 303 y 308 K. La adsorci-n en los asfaltenos floculados en masa fue la m ‡s importante con los isotermos correspondientes a un mecanismo de Freundlich. La elevada proporci-n de fenoles adsorbidos viene a sugerir una posible migraci-n de las molŽculas del fenol a travŽs de la estructura poco compacta de los

Adsorption of Methyl Orange, Pb2+ and Cd2+ from Aqueous Solution by Composites of Lignocellulose‐Montmorillonite Modified with Methacryloxypropyl Trimethoxysilane

“…Similar isotherms have been reported for the adsorption of monohydric phenols and many monosulfonated dyes onto polar substrates from a polar solvent like water 28. Jaoui, M. et al, 1998 also reported similar isotherms for the adsorption of phenol and 4‐chlorophenol onto petroleum asphaltenes 31…”

“…For the initial part of the S ‐curves, the more solute there is already adsorbed, the easier it is for additional solute to adsorb. This implies a side‐by‐side association between adsorbed molecules helping to hold them to the surface through ‘cooperative adsorption’ 28–31. Similar isotherms have been reported for the adsorption of monohydric phenols and many monosulfonated dyes onto polar substrates from a polar solvent like water 28.…”

Influences of Molecular Structure of Poly(styrene-co-octadecyl maleimide) on Stabilizing Asphaltenes in Crude Oil

“…Dodecylbenzenesulfonic acid (DBSA) has been found to effectively stabilize asphaltenes. It is because DBSA can be adsorbed to the asphaltene surface via acid–base interactions and the alkyl chains of the absorbed DBSA form a protective layer that provides steric stabilization for asphaltenes. , Furthermore, studies revealed that the efficacy of an amphiphilic additive depends on its ability to be adsorbed onto the asphaltene surface. − Although the stabilizers for asphaltenes have been investigated for a long time, the previous researches mainly focused on the small amphiphilic molecules. ,− A few recent studies − concentrated on the polymeric stabilizers for asphaltenes. Chang and Fogler found that dodecylphenolic resin and poly­(octadecene- co -maleic anhydride) with multiple polar groups were able to stabilize asphaltenes by the associations with asphaltenes.…”

Modeling and Simulation of Near-Wellbore Asphaltene Remediation Using Asphaltene Dispersants

“…Dissolution of asphaltene particles using dispersants is a two-step process (Permsukarome et al, 1997;Jaoui et al, 1998;Leon et al, 1999): (1) the dispersants are adsorbed on the surface of the asphaltene particles and (2) the interactions between adsorbed dispersant and asphaltene becomes dominant, which results in formations of asphaltene-dispersant complexes. The reactions between the dispersants and asphaltene particles are as follows:…”

“…These kinds of isotherms are related to a two-step adsorption mechanism mentioned earlier. In a separate study, Jaoui et al (1998) measured the asphaltene isotherms for different combinations of dispersantscrude oils. Based on the results, they also concluded that the asphaltene-dispersant interaction is a two-step process.…”