eprintid: 10053565 rev_number: 22 eprint_status: archive userid: 608 dir: disk0/10/05/35/65 datestamp: 2018-08-01 14:48:04 lastmod: 2021-09-20 22:23:48 status_changed: 2018-08-01 14:48:04 type: article metadata_visibility: show creators_name: Papavasileiou, KD creators_name: Michalis, VK creators_name: Peristeras, LD creators_name: Vasileiadis, M creators_name: Striolo, A creators_name: Economou, IG title: Molecular Dynamics Simulation of Water-Based Fracturing Fluids in Kaolinite Slit Pores ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F43 keywords: kaolinite, fracturing fluid, citric acid, methanol, molecular dynamics, NORM note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: The adsorption behavior inside kaolinite mesopores of aqueous solutions of various salts and additives is investigated using Molecular Dynamics simulations. In particular, we examine the various combinations of water + salt, water + additive, and water + salt + additive mixtures, where the salts examined are NaCl, CsCl, SrCl2 and RaCl2 and the additives are methanol and citric acid. Citric acid is modeled in two forms, namely fully protonated (H3A) and fully deprotonated (A3-), the latter being prevalent in neutral pH conditions, in accordance with the kaolinite structure employed. The force fields used for the individual system components include CLAYFF for the kaolinite mesopores, SPC/E for water, parameters optimized for the SPC/E water model based on hydration free energies (HFE) for ions and general Amber force field (GAFF) for the additives. The spatial distributions along the kaolinite pore are delineated and reveal the preferential adsorption behavior of the various species with respect to the gibbsite and siloxane surface, as well as the effect on this behavior of the interactions between the various species. Furthermore, we examine the hydrogen bonds formed between the kaolinite surfaces and water molecules as well as the additives. For the case of citric acid, which tends to aggregate, a cluster analysis is also carried out, in order to examine the effect of the various ions on the cluster formation. Finally, through the calculation of lateral diffusion coefficients and mean residence times, we provide insights on the mobility of the various species inside the kaolinite mesopores. date: 2018-08-02 date_type: published official_url: http://dx.doi.org/10.1021/acs.jpcc.8b03552 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1571613 doi: 10.1021/acs.jpcc.8b03552 lyricists_name: Striolo, Alberto lyricists_id: ASTRI68 actors_name: Striolo, Alberto actors_id: ASTRI68 actors_role: owner full_text_status: public publication: The Journal of Physical Chemistry C volume: 122 number: 30 pagerange: 17170-17183 issn: 1932-7455 citation: Papavasileiou, KD; Michalis, VK; Peristeras, LD; Vasileiadis, M; Striolo, A; Economou, IG; (2018) Molecular Dynamics Simulation of Water-Based Fracturing Fluids in Kaolinite Slit Pores. The Journal of Physical Chemistry C , 122 (30) pp. 17170-17183. 10.1021/acs.jpcc.8b03552 <https://doi.org/10.1021/acs.jpcc.8b03552>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10053565/1/Submitted%20manuscript.pdf