Attempts to Study a Water Evaporation Retardation by Soluble Surfactants

Lunkenheimer, Klaus; Zembala, Maria

doi:10.1006/jcis.1997.4781

Cited by 42 publications

(37 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been argued that surface active solutes can lower the evaporation rate considerably, possibly leading to large changes in γ e (Marek and Straub, 2001). Many studies of the effect of surfactants on water evaporation indicate a dramatic lowering of the evaporation rate upon sufficient surface coverage by surfactant molecules (Lunkenheimer and Zembala, 1997;Rusdi and Moroi, 2004;Seaver et al, 1992). Additionally, recent molecular dynamics (MD) simulations of condensation onto an aerosol particle coated with organics show a significantly lowered condensation probability (Chakraborty and Zachariah, 2008).…”

Section: Discussionmentioning

confidence: 99%

Determination of the evaporation coefficient of D<sub>2</sub>O

et al. 2008

View full text Add to dashboard Cite

Abstract. The evaporation rate of D 2 O has been determined by Raman thermometry of a droplet train (12-15 µm diameter) injected into vacuum (∼10 −5 torr). The cooling rate measured as a function of time in vacuum was fit to a model that accounts for temperature gradients between the surface and the core of the droplets, yielding an evaporation coefficient (γ e ) of 0.57±0.06. This is nearly identical to that found for H 2 O (0.62±0.09) using the same experimental method and model, and indicates the existence of a kinetic barrier to evaporation. The application of a recently developed transition-state theory (TST) model suggests that the kinetic barrier is due to librational and hindered translational motions at the liquid surface, and that the lack of an isotope effect is due to competing energetic and entropic factors. The implications of these results for cloud and aerosol particles in the atmosphere are discussed.

show abstract

Section: Discussionmentioning

confidence: 99%

Determination of the evaporation coefficient of D<sub>2</sub>O

et al. 2008

View full text Add to dashboard Cite

show abstract

“…9 Among the most recent works on this subject, it is worth to mention the use of soluble surfactants, which showed little influence on evaporation reduction. 10 New methods for accurately measuring evaporation reduction have also been developed, and may be useful for investigating details of the mechanisms behind the effect of monolayers on water evaporation. 11,12 Other works have focused attention on the influence of mixed films on evaporation reduction, and showed that the evaporation resistance of films of a pure fatty alcohol can be decreased or increased by adding small amounts of other surfactants, the latter effect being ascribed to the less defective structure of the mixed films studied.…”

Section: Introductionmentioning

confidence: 99%

Reduction of evaporation of natural water samples by monomolecular films

Gugliotti¹,

Baptista²,

Politi³

2005

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

A capacidade de filmes monomoleculares de álcoois graxos em reduzir a evaporação de amostras naturais de água, coletadas em dois reservatórios de São Paulo (Guarapiranga e Billings), foi estudada em laboratório. As reduções da evaporação foram determinadas diretamente, medindo-se o volume de água evaporado dos recipientes de teste após certo tempo. Filmes mistos de hexadecanol e octadecanol apresentaram alto potencial de redução da evaporação (até 57%) e persistência na superfície da água, por cerca de 48 horas. Uma breve discussão sobre a melhor eficiência desses filmes mistos na redução da evaporação de água é também apresentada.The ability of monomolecular films of fatty alcohols in reducing evaporation of natural water samples collected from two reservoirs in São Paulo (Guarapiranga and Billings) was studied in the laboratory. Evaporation reductions were determined directly by measuring the volume of water evaporated from the test recipients after a certain period of time. Mixed films of hexadecanol and octadecanol showed high potential of evaporation reduction (up to 57%) and persistence on the water surface of ca. 48 hours. A brief discussion on the better efficiency of these mixed films in reducing water evaporation is also presented. Keywords: water, evaporation, fatty alcohols, monomolecular films, surface tension IntroductionWater is the most precious natural resource available to mankind. Most of our usable fresh water is retained in lakes and reservoirs, but this type of storage allows for the greatest loss of water by evaporation. The increasing demand for municipal and industrial fresh water, and the current increase in the global temperature indicate that it is necessary to employ techniques for reducing evaporation aiming at the conservation of water supplies.It has been known for a long time that monomolecular films of certain surfactants can retard water evaporation. 1 This seems to be the only viable technology for reducing the evaporative losses of water from reservoirs. 2 For many years, important studies in laboratory scale were carried out in order to identify the optimal substances and conditions for reducing water evaporation. [3][4][5] Among the surfactants tested, biodegradable fatty alcohols of low toxicity presented the highest resistance to water evaporation, especially 1-hexadecanol and 1-octadecanol. 2 The first field experiment was conducted in Australia in the beginning of the 50's, and the obtained evaporation reductions of 30% called attention of many research groups and governments around the world. 6,7 In the following decades, several experimental and theoretical works were published, and the main conclusions were collected in a review published in 1986. 8 Although the spreading of a monomolecular film on the surface of a reservoir has been considered as an alternative technology for fresh water conservation by the United Nations Environment Programme, only a few investigations on this subject have been reported in the last years. 9 Among the most recent works on this subje...

show abstract

“…It is well known in the physical chemistry literature that surfactants may also inhibit the evaporation rate, by reducing the effective area along the liquid-air interface through which evaporation is possible. [32][33][34][35][36][37] One question that arises is how this effect of surfactants on the evaporation flux may affect the flow dynamics and therefore the resulting particle deposition patterns.…”

mentioning

confidence: 99%

Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

2016

View full text Add to dashboard Cite

We consider the flow dynamics of a thin evaporating droplet in the presence of an insoluble surfactant and non-interacting particles in the bulk. Based on lubrication theory, we derive a set of evolution equations for the film height, the interfacial surfactant and bulk particle concentrations, taking into account the dependence of the liquid viscosity on the local particle concentration. An important ingredient of our model is that it takes into account the fact that the surfactant adsorbed at the interface hinders evaporation. We perform a parametric study to investigate how the presence of surfactants affects the evaporation process as well as the flow dynamics with and without the presence of particles in the bulk. Our numerical calculations show that the droplet life-time is affected significantly by the balance between the ability of surfactant to * To whom correspondence should be addressed † Department of Chemical Engineering, University of Patras, Patras 26500, Greece ‡ Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy 502 285, Telangana, India ¶ Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK 1 enhance spreading suppressing the effect of thermal Marangoni stresses-induced motion and to hinder the evaporation flux through the reduction of effective interfacial are of evaporation, which tend to accelerate and decelerate the evaporation process, respectively. For particle-laden droplets and in the case of dilute solutions, the droplet life-time is found to be weakly-dependent on the initial particle concentration. We also show that the particle deposition patterns are influenced strongly by the direct effect of surfactant on the evaporative flux; in certain cases, the "coffee stain" effect is enhanced significantly. A discussion of the delicate interplay between the effects of capillary pressure, solutal and thermal Marangoni stresses, which drive the liquid flow inside the evaporating droplet giving rise to the observed results is provided herein.

show abstract

Attempts to Study a Water Evaporation Retardation by Soluble Surfactants

Cited by 42 publications

References 9 publications

Determination of the evaporation coefficient of D<sub>2</sub>O

Determination of the evaporation coefficient of D<sub>2</sub>O

Reduction of evaporation of natural water samples by monomolecular films

Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

Contact Info

Product

Resources

About

Attempts to Study a Water Evaporation Retardation by Soluble Surfactants

Cited by 42 publications

References 9 publications

Determination of the evaporation coefficient of D&lt;sub&gt;2&lt;/sub&gt;O

Determination of the evaporation coefficient of D&lt;sub&gt;2&lt;/sub&gt;O

Reduction of evaporation of natural water samples by monomolecular films

Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

Contact Info

Product

Resources

About

Determination of the evaporation coefficient of D<sub>2</sub>O

Determination of the evaporation coefficient of D<sub>2</sub>O