Effect of salinity on formaldehyde interaction with quartz sand and kaolinite colloid particles: batch and column experiments

Fountouli, Theodosia V.; Chrysikopoulos, Constantinos V.; Tsanis, Ioannis K.

doi:10.1007/s12665-019-8147-x

Cited by 8 publications

(17 citation statements)

References 72 publications

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“…This observation suggests that there was no significant interaction between FA and the sand or the air-water interfaces in the unsaturated columns (see Figure 2). Note that Fountouli et al [32] have also reported the absence of FA retention by the quartz sand in batch and water saturated packed columns. Furthermore, for each breakthrough curve, the M r values, as calculated with Equation (2), and the ratio of M 1 for FA to that for tracer (M 1(FA) /M 1(tr) ) were computed and listed in Table 2.…”

Section: Theoretical Considerationsmentioning

confidence: 90%

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Effect of Clay Colloid Particles on Formaldehyde Transport in Unsaturated Porous Media

Fountouli

Chrysikopoulos

2020

Water

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This study examines the effects of two representative colloid-sized clay particles (kaolinite, KGa-1b and montmorillonite, STx-1b) on the transport of formaldehyde (FA) in unsaturated porous media. The transport of FA was examined with and without the presence of clay particles under various flow rates and various levels of saturation in columns packed with quartz sand, under unsaturated conditions. The experimental results clearly suggested that the presence of clay particles retarded by up to ~23% the transport of FA in unsaturated packed columns. Derjaguin–Landau–Verwey–Overbeek (DLVO) interaction energy calculations demonstrated that permanent retention of clay colloids at air-water interfaces (AWI) and solid-water interfaces (SWI) was negligible, except for the pair (STx-1b)–SWI. The experimental results of this study showed that significant clay colloid retention occurred in the unsaturated column, especially at low flow rates. This deviation from DLVO predictions may be explained by the existence of additional non-DLVO forces (hydrophobic and capillary forces) that could be much stronger than van der Waals and double layer forces. The present study shows the important role of colloids, which may act as carriers of contaminants.

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Section: Theoretical Considerationsmentioning

confidence: 90%

“…For the determination of FA concentration, the Nash colorimetric method was employed [31], which has been widely used in a number of studies [32][33][34]. In brief, a volume of FA-containing solution is mixed with Nash reagent at a maximum concentration of 8 mg/L (1:1 v/v).…”

Section: Formaldehyde (Fa)mentioning

confidence: 99%

Effect of Clay Colloid Particles on Formaldehyde Transport in Unsaturated Porous Media

Fountouli

Chrysikopoulos

2020

Water

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“…Current methods for removing FA from water depend mainly on physical adsorption with a removal success rate of 60-65% [22] and chemical catalytic oxidation [23]. Many materials have been shown to be effective in adsorbing FA, such as activated carbon, clays and carbon nanotubes [24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

“…Given that both FA and TiO 2 are frequently released into the environment, they can easily infiltrate subsurface formations. It should be noted that the adsorption of FA onto quartz sand was reported to be weak [27]. Consequently, it is worthwhile to study the interaction between FA and TiO 2 in the presence of a common rock-forming mineral such as quartz sand.…”

Section: Introductionmentioning

confidence: 99%

Interaction of Titanium Dioxide with Formaldehyde in the Presence of Quartz Sand under Static and Dynamic Conditions

Stefanarou

Chrysikopoulos

2021

Water

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Formaldehyde (FA) is an extremely active compound that is widely used in numerous applications. Given that FA is a known carcinogen, it is essential to remove it from the environment. Titanium dioxide (TiO2), due to its special physicochemical properties, is a promising adsorbent for the removal of specific organic compounds from aqueous solutions. In this study, the interaction of TiO2 with FA in the presence and absence of quartz sand, the most common mineral on the Earth’s surface, was investigated under static and dynamic (batch) conditions, at 25 °C. The experimental data suggested that the sorption of FA onto TiO2 can be described adequately by a pseudo-second order kinetic model, indicating that the main sorption mechanism was chemisorption. It was observed that the combination of TiO2 and quartz sand could1 lead up to effective removal of FA from aqueous samples.

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“…The majority of research on the transport of colloidal suspensions in porous media is devoted to the attachment phenomena (Bradford et al, 2002;Chrysikopoulos et al, 2017;Elimelech et al, 2013;Fountouli et al, 2019). A macroscopic mass balance approach links the attachment coefficient to the concentration of colloids, Darcy velocity, adsorption capacity, and diffusion coefficient.…”

Section: Introductionmentioning

confidence: 99%

Mobilization of Attached Clustered Colloids in Porous Media

Chequer

Bedrikovetsky

Carageorgos

et al. 2019

Water Resources Research

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The models for colloidal mobilization in porous media are often based on Derjaguin‐Landau‐Verwey‐Overbeek interaction energy profiles. Despite abundant evidence on mobilization of particle clusters, the models to date have been limited to single colloid‐surface Derjaguin‐Landau‐Verwey‐Overbeek calculations. We show through visualization tests, qualitative and quantitative modeling, and data evaluation, that the widely accepted single colloid‐single surface isolation does not always adequately describe colloid behavior. The experiments were performed with kaolinite and latex particles mobilized from sand grains and glass beads in a transparent visualization cell. The particles were mobilized under increasing velocity and pH and decreasing salinity. The detachment conditions were determined by a torque balance of electrostatic, drag, lifting, and gravity forces, combined with a theory of a contact area between a single soft particle and a plane surface. The tests show that the calculations based on the mechanical equilibrium of a single particle on a plane surface significantly underestimate the critical detachment velocity. A better prediction is obtained using a cluster approximation. High‐resolution images taken during mobilization tests show 2‐12 particle clusters on media surface and in its proximity. The mechanical‐equilibrium calculations show that the attaching torque for clusters with assumed size and cylindrical shape is significantly higher than that for single particles. The critical detachment velocity of clusters, derived from the mechanical‐equilibrium force and torque balances, is higher than for single particles and provides a better fit to the experimental data. Our study suggests that a cluster approximation can accurately predict the mobilization of colloids in porous media.

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Effect of salinity on formaldehyde interaction with quartz sand and kaolinite colloid particles: batch and column experiments

Cited by 8 publications

References 72 publications

Effect of Clay Colloid Particles on Formaldehyde Transport in Unsaturated Porous Media

Effect of Clay Colloid Particles on Formaldehyde Transport in Unsaturated Porous Media

Interaction of Titanium Dioxide with Formaldehyde in the Presence of Quartz Sand under Static and Dynamic Conditions

Mobilization of Attached Clustered Colloids in Porous Media

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