Adsorption of Anionic Surfactant by Activated Carbon: Effect of Surface Chemistry, Ionic Strength, and Hydrophobicity

Wu, Sophie Hua; Pendleton, Phillip

doi:10.1006/jcis.2001.7905

Cited by 159 publications

(78 citation statements)

References 36 publications

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“…The unexpected, from the viewpoint of the structure of the two compounds, gradation of the changes in the r values can be interpreted as a result of a positive effect of solvation via hydrogen bonding of the ESLS molecule on adsorbability of this compound. The proposed adsorption mechanism is hypothetical but it offers a good interpretation of experimental studies and corresponds with the current theories of adsorption of surfactants at the solid-solution interface [17][18][19][20][21][22][23][24][25][26][27][28][29][30]. The credibility of this hypothesis does not interfere with interpretation of the results of tribological tests.…”

Section: Micellar Solutions Of Alkyl Sulfatessupporting

confidence: 68%

“…They exhibit high surface activity. They can form micelles and liquid crystalline structures both at the interface and in the bulk phase [17][18][19][20][21][22][23][24][25][26][27][28][29][30]. The ample experimental material makes it possible to predict the effect of the structure of a compound and the share of the hydrophilic and hydrophobic parts on adsorption properties [27,28,[31][32][33].…”

Section: Resultsmentioning

confidence: 99%

“…The ample experimental material makes it possible to predict the effect of the structure of a compound and the share of the hydrophilic and hydrophobic parts on adsorption properties [27,28,[31][32][33]. An increase in the hydrophobic part generally brings about a considerable increase in the excess values and a decrease in the critical concentration of surface and bulk micelles [17][18][19][20][21][22][23][24][25][26][27][28][29][30]. According to Traube's rule, an alkyl chain growth by a CH 2 group causes a threefold reduction in CMC and CSAC [24], but a growth of the hydrophilic part results in a decrease in the amount of the adsorbed compound and a shift in the values of CMC and CSAC towards higher concentrations.…”

Section: Resultsmentioning

confidence: 99%

“…The SLS molecule has a higher share of the hydrophobic part compared to ESLS and its concentration in that space should be higher. In the second stage, adsorption of monomers from the bulk phase and monomers formed due to decomposition of micelles takes place [17][18][19][20][21][22][23][24][25][26][27][28][29][30]56]. This process becomes complicated because solvated surfactant molecules adsorb on the surface [17][18][19][20][21][22][23][24][25][26][27][28][29][30]57].…”

Section: Micellar Solutions Of Alkyl Sulfatesmentioning

confidence: 99%

“…In addition, ESLS molecules undergo hydration as a result of formation of hydrogen bonds of water molecules with two oxygen atoms from ether groups. Interactions of the hydrophilic part of the ESLS molecule with the surface are thus weaker (enthalpic separation) than interactions of the hydrophilic part of the SLS molecule and it is ''pushed out'' of the surface towards the solvent [17][18][19][20][21][22][23][24][25][26][27][28][29][30]58]. Hence, it is the entropic effect connected with spatial positioning of the hydrophilic part that decides about adsorption up to the concentration value equal to CMC.…”

Section: Micellar Solutions Of Alkyl Sulfatesmentioning

confidence: 99%

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The Effect of Concentration on Lubricating Properties of Aqueous Solutions of Sodium Lauryl Sulfate and Ethoxylated Sodium Lauryl Sulfate

2010

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The objective of this study was to formulate new ecological lubricating substances, primarily water-based, and to verify their tribological and physicochemical properties. Initially, simple binary solutions were investigated. Then, various additives were added depending on application targets. Two alkyl sulfates were selected as additives modifying lubricating properties of water: sodium lauryl sulfate (SLS) and ethoxylated sodium lauryl sulfate (ESLS). They have an identical hydrophobic part in the form of an alkyl chain consisting of 12 carbon atoms. The SO 4 2-anion forms the hydrophilic part in SLS molecules, whereas an ESLS molecule also contains two mers of ethylene oxide which cause an increase in its hydrophilicity relative to SLS. Both SLS and ESLS exhibit high surface activity measured by their surface tension. Micelles form in aqueous solutions of alkyl sulfates at low concentrations of the order of 1%, whereas the presence of liquid crystalline phases can be found at the concentrations of 40 and 70%. High surface activity and formation of structures in the solutions (micelles, mesophases) formed the basis for application of the compounds as additives modifying lubricating properties. Tribological properties of aqueous solutions of alkyl sulfates were verified with a four-ball machine (T02 tester) at a constant load of 2 kN. The values of friction coefficient (l) were a measure of motion resistance, while the wear scar diameter (d) was a measure of wear. Alkyl sulfates significantly improve tribological properties of water. The coefficient of friction decreased sixfold and the wear scar diameter decreased by as much as twofold relative to the base. Non-monotonic changes in the tribological properties measured were observed as a function of concentration of additives. An attempt was made to relate those atypical changes with the presence of micelles and mesophases in both the surface phase and the bulk phase. In the model proposed the whole concentration range was divided into four areas in which tribological properties correspond well with physicochemical properties, particularly with the structures formed in solutions and at the interface.

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Section: Micellar Solutions Of Alkyl Sulfatessupporting

confidence: 68%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Micellar Solutions Of Alkyl Sulfatesmentioning

confidence: 99%

Section: Micellar Solutions Of Alkyl Sulfatesmentioning

confidence: 99%

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The Effect of Concentration on Lubricating Properties of Aqueous Solutions of Sodium Lauryl Sulfate and Ethoxylated Sodium Lauryl Sulfate

2010

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Simulation of kinetic behavior of natural surfactants adsorption using a new robust approach

Daryasafar

Borazjani

Daryasafar

2018

Journal of Chemometrics

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Surfactant-based enhanced oil recovery techniques are known as promising methods for mobilizing the trapped oil in porous media. Surfactants can improve oil recovery by modifying the wettability of rock minerals and also by reducing the interfacial tension between injected water and the trapped oil. Natural surfactants have been introduced as good candidates for enhanced oil recovery applications. In addition, they are less expensive and also have less detrimental environmental effects in comparison with the industrial surfactants. Various empirical models have been proposed for simulating the kinetic behavior of surfactants adsorption, but these models suffer from overestimation and underestimation and they cannot be generalized for even a type of surfactant. Therefore, it is crucial to develop a new model that can overcome these issues. In this study, a new simple, rapid, and accurate model based on least square support vector machines (LSSVMs) was developed for predicting the kinetic adsorption density of natural surfactants on both sandstone and carbonate minerals. Coupled simulated annealing algorithm (CSA) is used for tuning the parameters of the model. Predicted values by this model were in an excellent agreement with experimental values with a coefficient of determination of 0.990. The results demonstrated that the proposed LSSVM-CSA model has the best performance in comparison with the other well-established kinetic models. Furthermore, the model reliability was investigated over input parameters changes and showed the acceptable efficiency of the proposed model.

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Adsorption of single‐ring model naphthenic acid from oil sands tailings pond water using physically activated petroleum coke

et al. 2023

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Petroleum coke‐derived activated cokes were prepared and used for the adsorptive removal of a single‐ring naphthenic acid (NA) from synthetic oil sands process affected water (OSPW). CO2 activation produced carbon with a larger mesopore volume fraction (0.67) than steam activation (0.25). Interestingly, prolonging the activation time of CO2 from 6 to 9 h led to a simultaneous increase in specific surface area (276–405 m2/g) and mesopore volume (0.51–0.67). Furthermore, a positive relationship was found between the pseudo‐second‐order kinetic rate constant and the mesoporous volume of the activated coke. This suggests both the importance of pore size on kinetics and the fact that physical activation with a reagent such as CO2 may be better suited than chemical activation due to its ability to create mesopores. Although enlarging the pores and accelerating the adsorption rate, post‐oxidation had detrimental effects on adsorption capacity, resulting in a decrease in equilibrium adsorbed amount from 115 to 34 mg/g, a 70% decrease, when post‐oxidized with O2, due to the negative charge of oxygen‐containing functional groups. On the other hand, the measured adsorption capacity increased by over 60% when activated coke was treated with ammonia, a result of the positively charged nitrogen‐containing surface groups. Finally, in real OSPW, the activated coke had a much lower capacity for total acid‐extractable organics than for the model NA. Therefore, activated petroleum coke may not be the best choice for treating raw tailings pond water and may be better suited for polishing.

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Adsorption of Anionic Surfactant by Activated Carbon: Effect of Surface Chemistry, Ionic Strength, and Hydrophobicity

Cited by 159 publications

References 36 publications

The Effect of Concentration on Lubricating Properties of Aqueous Solutions of Sodium Lauryl Sulfate and Ethoxylated Sodium Lauryl Sulfate

The Effect of Concentration on Lubricating Properties of Aqueous Solutions of Sodium Lauryl Sulfate and Ethoxylated Sodium Lauryl Sulfate

Simulation of kinetic behavior of natural surfactants adsorption using a new robust approach

Adsorption of single‐ring model naphthenic acid from oil sands tailings pond water using physically activated petroleum coke

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