Unexpected inhibition of CO2 gas hydrate formation in dilute TBAB solutions and the critical role of interfacial water structure

Nguyễn, Như Gia; Nguyen, Anh V.; Nguyen, Khoi Tan; Rintoul, Llew; Dang, Liem X.

doi:10.1016/j.fuel.2016.08.006

Cited by 57 publications

(49 citation statements)

References 48 publications

(67 reference statements)

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“…However, the literature suggests that the advantage of using TBAB lies in its ability to be a thermodynamic promoter, which is not yet noticeable at these low concentrations. Nguyen et al also reported a decreasing trend with increasing TBAB concentration, similar to the one presented here, but in carbon dioxide gas hydrate systems. They indicated that gas uptake is at a minimum at 1250 ppm TBAB, and gas uptake will increase with either increasing or decreasing the TBAB concentration from this point.…”

Section: Resultssupporting

confidence: 88%

“…This means that the driving force for this concentration is approximately 5 % lower than the other concentrations (1423 kPa versus 1500 kPa). Nguyen et al have explained this inhibition at dilute TBAB concentration as a gas‐water interface adsorption of TBAB that gives rise to inhibition at low concentrations. The promotion effect of TBAB is not strong enough at these low concentrations to compensate for the inhibition.…”

Section: Resultsmentioning

confidence: 99%

“…Another study showed that a 40–45 wt% TBAB solution may be a promising cold storage material for air conditioning systems due to its high phase change temperature and its improved overall conversion of liquid to gas hydrate . A study that sparked interest for this report was completed by Nguyen et al, which looked at the influence of a range of TBAB concentrations (0.025 to 3 wt%) on gas uptake during the formation of CO 2 gas hydrates. They noticed that low concentrations of TBAB inhibited growth kinetics, where a minimum growth rate was observed at 0.125 wt% TBAB.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Methane gas hydrate kinetics with mixtures of sodium dodecyl sulphate and tetrabutylammonium bromide

Renault-Crispo

Servio

2018

Can J Chem Eng

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The effect of combining a thermodynamic promoter, tetrabutylammonium bromide (TBAB), with a kinetic promoter, sodium dodecyl sulphate (SDS), to a methane clathrate system was investigated. Kinetic growth experiments were conducted in a semi‐batch stirred tank crystallizer at driving forces of 1500 kPa using a range of 100 to 1500 ppm SDS and 200 to 200 000 ppm TBAB. Solutions containing low concentrations of TBAB in water reduced methane hydrate growth rates up to 55 % for 1250 ppm TBAB compared to pure water. Solutions containing 900 ppm SDS in water enhanced the growth rate by 880 % compared to pure water. Solutions were then tested combining both promoters. The gradual addition of SDS from concentrations between 100 to 1250 ppm to low‐concentration TBAB systems between 200 to 1250 ppm was initially found to reduce growth kinetics, but eventually increased the growth rates once a threshold SDS concentration was reached. In all cases, the promoting effect of the SDS was more pronounced in the absence of the TBAB. The growth kinetics of systems containing 5 and 20 wt% TBAB also followed a similar inhibition‐promotion trend with the SDS concentration. An increase of 177 % in the gas consumption rate was observed when 1500 ppm SDS was added to the 20 wt% TBAB clathrate system. This work demonstrates that SDS can be added to a TBAB‐water‐methane system to enhance gas consumption rates, but care must be taken to ensure that the concentration of the additives places the system in a promotion regime.

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Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Methane gas hydrate kinetics with mixtures of sodium dodecyl sulphate and tetrabutylammonium bromide

Renault-Crispo

Servio

2018

Can J Chem Eng

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“…For example, while SDS is widely known an effective promoter, Sowa et al 36 recently reported that this surfactant could act as an inhibitor of gas hydrate formation in a wide range of experimental condition. Similarly, we have shown in our recent work 37 that tetra-n-butyl ammonium bromide (TBAB), also a well-known gas hydrate promoter, could display a strong inhibiting effect on CO 2 gas hydrate formation when it was used at millimolar concentration.…”

mentioning

confidence: 55%

“…In this section, we show how the effect of a mixture of SDS and TBAB is different from the individual effect of each surfactant. In our recent work 37 , we showed that TBAB (tetra-nbutylammonium bromide) displayed a strong inhibition of carbon dioxide hydrate formation when it was used at the concentration of 3.6 mM. Thus, we used this concentration for our aim here.…”

Section: Effect Of Mixture Of Sds and Tbabmentioning

confidence: 99%

The inhibition of methane hydrate formation by water alignment underneath surface adsorption of surfactants

Nguyễn

Nguyen

Dang

2017

Fuel

Self Cite

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Sodium dodecyl sulfate (SDS) has been widely shown to strongly promote the formation of methane hydrate. Here we show that SDS displays an extraordinary inhibition effect on methane hydrate formation when the surfactant is used in sub-millimolar concentration (around 0.3 mM). We have also employed Sum Frequency Generation vibrational spectroscopy (SFG) and molecular dynamics simulation (MDS) to elucidate the molecular mechanism of this inhibition. The SFG and MDS results revealed a strong alignment of water molecules underneath surface adsorption of SDS in its sub-millimolar solution. Interestingly, both the alignment of water and the inhibition effect (in 0.3 mM SDS solution) went vanishing when an oppositely-charged surfactant (tetra-n-butylammonium bromide, TBAB) was suitably added to produce a mixed solution of 0.3 mM SDS and 3.6 mM TBAB. Combining structural and kinetic results, we pointed out that the alignment of water underneath surface adsorption of dodecyl sulfate (DS-) anions gave rise to the unexpected inhibition of methane hydration formation in sub-millimolar solution of SDS. The adoption of TBAB mitigated the SDS-induced electrostatic field at the solution's surface and, therefore, weakened the alignment of interfacial water which, in turn, erased the inhibition effect. We discussed this finding using the concept of activation energy of the interfacial formation of gas hydrate. The main finding of this work is to reveal the interplay of interfacial water in governing gas hydrate formation which sheds light on a universal molecular-scale understanding of the influence of surfactants on gas hydrate formation.

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Effects of Charged Surfactants on Interfacial Water Structure and Macroscopic Properties of the Air‐Water Interface

Nguyen,

Raji,

Nguyen

et al. 2023

ChemPhysChem

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Surfactants are used to control the macroscopic properties of air‐water interfaces. However, the link between the molecular structure of surfactant adsorption and macroscopic properties is poorly understood. Using sum‐frequency generation spectroscopy and molecular dynamics simulation, we show that two ionic surfactants (dodecyl trimethylammonium bromide and sodium dodecyl sulphate) with the same carbon chain lengths and head group charge magnitude (but different signs) can interact and reorient interfacial water molecules differently. DTAB forms a thicker but sparser interfacial layer than SDS. It is due to the deep penetration into the adsorption zone of Br‐ counterions compared to smaller Na+ ones, and also due to the flip‐flop orientation of water molecules. SDS alters two distinctive interfacial water layers into a layer where H+ points to the air, forming strong hydrogen bonding with the sulphate headgroup. In contrast, only weaker dipole‐dipole interactions with the DTAB headgroup are formed as they reorient water molecules with H+ point down to water. Hence, with more molecules adsorbed at the interface, SDS builds up a higher interfacial pressure than DTAB, producing lower surface tension and higher foam stability at a similar bulk concentration. Our findings offer improved knowledge for understanding various processes in the industry and nature.

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Unexpected inhibition of CO2 gas hydrate formation in dilute TBAB solutions and the critical role of interfacial water structure

Cited by 57 publications

References 48 publications

Methane gas hydrate kinetics with mixtures of sodium dodecyl sulphate and tetrabutylammonium bromide

Methane gas hydrate kinetics with mixtures of sodium dodecyl sulphate and tetrabutylammonium bromide

The inhibition of methane hydrate formation by water alignment underneath surface adsorption of surfactants

Effects of Charged Surfactants on Interfacial Water Structure and Macroscopic Properties of the Air‐Water Interface

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