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Murota K, Saito T. Pore size effects on surface charges and interfacial electrostatics of mesoporous silicas. Phys Chem Chem Phys 2022; 24:18073-18082. [PMID: 35876621 DOI: 10.1039/d2cp02520e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Water in confinement becomes more structured than bulk water, and its properties, such as the dielectric constant, change. It remains unclear, however, how the interfacial reactions in confinement, such as the adsorption of ions on the surfaces of small pores, differ from those in larger spaces. We focused on the deprotonation reaction of hydroxyl groups, a fundamental surface reaction, and investigated the dependence of the surface charge density on pore size by determining the surface charge densities of six types of mesoporous silicas with micropores and mesopores at different ionic strengths and pH levels from batch titration tests. The surface complexation model assuming a potential distribution based on the Poisson-Boltzmann equation in cylindrical coordinates was fitted to the obtained surface charge densities to relate the electrostatics near the surface to the surface reaction. The results showed that the absolute values of the surface charge densities decreased with decreasing pore diameter due to the overlap of the electrical double layers. Furthermore, the capacitance of the Stern layer optimized by fitting decreased with decreasing pore diameter, especially in pores smaller than 4 nm in diameter, which suggested that the dielectric constants of water decreased near the surfaces of small pores.
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Affiliation(s)
- Kento Murota
- Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. .,Regulatory Standard and Research Department, Secretariat of Nuclear Regulation Authority, 1-9-9 Roppongi, Minato-ku, Tokyo 106-8450, Japan
| | - Takumi Saito
- Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakata Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1188, Japan
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The non-linear effect of oil polarity on the efficiency of low salinity waterflooding: A pore-level investigation. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.117069] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Alan BO, Barisik M. Size and roughness dependent temperature effects on surface charge of silica nanoparticles. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
This study examines how the several major industries, associated with a carbon artifact production, essentially belong to one, closely knit family. The common parents are the geological fossils called petroleum and coal. The study also reviews the major developments in carbon nanotechnology and electrocatalysis over the last 30 years or so. In this context, the development of various carbon materials with size, dopants, shape, and structure designed to achieve high catalytic electroactivity is reported, and among them recent carbon electrodes with many important features are presented together with their relevant applications in chemical technology, neurochemical monitoring, electrode kinetics, direct carbon fuel cells, lithium ion batteries, electrochemical capacitors, and supercapattery.
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Affiliation(s)
- César A C Sequeira
- CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal
- CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal
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Sen T, Barisik M. Slip Effects on Ionic Current of Viscoelectric Electroviscous Flows through Different Length Nanofluidic Channels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:9191-9203. [PMID: 32635731 DOI: 10.1021/acs.langmuir.0c01457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The pressure driven slip flow of an electrolyte solution is studied through different nanofluidic channel lengths at varying salt concentrations. The viscous-thickening due to the electrostatic interactions within the electric double layer and the reverse ionic transport due to the streaming potential are developed. The influence of the Navier slip boundary condition is described under both electroviscous and viscoelectric effects with a surface charge regulation (CR) model while the observed behavior is compared and validated with molecular dynamic (MD) calculations from multiple studies. Results show that electroviscous and viscoelectric effects decrease transport. Earlier studies at the no slip boundary presented an increase of ionic current by increasing salt concentration and decreasing channel length. In contrast, our study found that the ionic current occurred almost independent of both salt concentration and channel length, except for very short channels and very low salt concentrations, when electroviscous and viscoelectric effects were considered. In the case of the constant slip length condition, ionic conduction was enhanced, but velocity slip developing on surfaces showed significant variation based on the salt concentration and channel length. This is due to the natural CR behavior enhancing the surface charge and consequential near surface electrohydrodynamics as a result of increase in salt concentration and/or decrease of channel length. Considering that the electroviscous effect alone creates up to 70% lower velocity slips than Poiseuille flow predictions, while further including the viscoelectric effect, results in an almost no-slip condition at high salt concentrations and/or short channels. As a result, the ionic current of a viscoelectric electroviscous slip flow is found to be equal to 1/3 of an electroviscous slip flow and to decrease with a decrease in the channel length.
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Affiliation(s)
- Tumcan Sen
- Department of Mechanical Engineering, Izmir Institute Of Technology, Izmir 35430, Turkey
| | - Murat Barisik
- Department of Mechanical Engineering, Izmir Institute Of Technology, Izmir 35430, Turkey
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Mo WC, Yu J, Gao LZ, Liu Y, Wei Y, He RQ. Reversible Inhibition of Iron Oxide Nanozyme by Guanidine Chloride. Front Chem 2020; 8:491. [PMID: 32596209 PMCID: PMC7301555 DOI: 10.3389/fchem.2020.00491] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 05/12/2020] [Indexed: 11/13/2022] Open
Abstract
Nanozymes have been widely applied in bio-assays in the field of biotechnology and biomedicines. However, the physicochemical basis of nanozyme catalytic activity remains elusive. To test whether nanozymes exhibit an inactivation effect similar to that of natural enzymes, we used guanidine chloride (GuHCl) to disturb the iron oxide nanozyme (IONzyme) and observed that GuHCl induced IONzyme aggregation and that the peroxidase-like activity of IONzyme significantly decreased in the presence of GuHCl. However, the aggregation appeared to be unrelated to the quick process of inactivation, as GuHCl acted as a reversible inhibitor of IONzyme instead of a solo denaturant. Inhibition kinetic analysis showed that GuHCl binds to IONzyme competitively with H2O2 but non-competitively with tetramethylbenzidine. In addition, electron spin resonance spectroscopy showed that increasing GuHCl level of GuHCl induced a correlated pattern of changes in the activity and the state of the unpaired electrons of the IONzymes. This result indicates that GuHCl probably directly interacts with the iron atoms of IONzyme and affects the electron density of iron, which may then induce IONzyme inactivation. These findings not only contribute to understanding the essence of nanozyme catalytic activity but also suggest a practically feasible method to regulate the catalytic activity of IONzyme.
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Affiliation(s)
- Wei-Chuan Mo
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, University of the Chinese Academy of Sciences, CAS, Beijing, China
| | - Jia Yu
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, University of the Chinese Academy of Sciences, CAS, Beijing, China
| | - Li-Zeng Gao
- CAS Engineering Laboratory for Nanozyme, Institute of Biophysics Key Laboratory of Protein and Peptide Drugs, Institute of Biophysics, CAS, Yangzhou, China
| | - Ying Liu
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, University of the Chinese Academy of Sciences, CAS, Beijing, China.,School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China
| | - Yan Wei
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, University of the Chinese Academy of Sciences, CAS, Beijing, China.,CAS Key Laboratory of Mental Health Laboratory, Institute of Psychology, Beijing, China
| | - Rong-Qiao He
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, University of the Chinese Academy of Sciences, CAS, Beijing, China.,Southwest Medical University, Luzhou, China
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Singappuli-Arachchige D, Slowing II. Control of interfacial pH in mesoporous silica nanoparticles via surface functionalization. J Chem Phys 2020; 152:034703. [PMID: 31968970 DOI: 10.1063/1.5138912] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The pH at silica-water interfaces (pHint) was measured by grafting a dual emission fluorescent probe (SNARF) onto the surface of mesoporous silica nanoparticles (MSN). The values of pHint of SNARF-MSN suspended in water were different from the pH of the bulk solution (pHbulk). The addition of acid or base to aqueous suspensions of SNARF-MSN induced much larger changes in pHbulk than pHint, indicating that the interface has buffering capacity. Grafting additional organic functional groups onto the surface of SNARF-MSN controls the pHint of its buffering region. The responses of pHint to variations in pHbulk are consistent with the acid/base properties of the surface groups as determined by their pKa and are affected by electrostatic interactions between charged interfacial species as evidenced by the dependence of ζ-potential on pHbulk. Finally, as a proof of principle, we demonstrate that the hydrolysis rate of an acid-sensitive acetal can be controlled by adjusting pHint via suitable functionalization of the MSN surface. Our findings can lead to the development of nanoreactors that protect sensitive species from adverse conditions and tune their chemical reactivity.
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Sen T, Barisik M. Pore connectivity effects on the internal surface electric charge of mesoporous silica. Colloid Polym Sci 2019. [DOI: 10.1007/s00396-019-04555-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sen T, Barisik M. Internal surface electric charge characterization of mesoporous silica. Sci Rep 2019; 9:137. [PMID: 30644430 PMCID: PMC6333811 DOI: 10.1038/s41598-018-36487-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 11/22/2018] [Indexed: 11/22/2022] Open
Abstract
Mesoporous silica is an emerging technology to solve problems of existing and to support projected revolutionary applications ranging from targeted drug delivery to artificial kidney. However, one of the major driving mechanisms, electric charging of internal mesoporous surfaces, has not been characterized yet. In the nanoscale confinements of mesoporous structures made of pore throats and pore voids, surface charges diverge from existing theoretical calculations and show local variation due to two occurrences. First, when the size of pore throat becomes comparable with the thickness of ionic layering forming on throats’ surfaces, ionic layers from opposite surfaces overlap so that ionic concentration on the surface becomes different than Boltzmann distribution predicts, and there will no longer be an equilibrium of zero electric potential at pore throat centers. Second, when this non zero potential inside throats becomes different than the potential of pore voids, ionic diffusion from void to throat creates axial ionic variation on surfaces. For such a case, we performed a pore level analysis on mesoporous internal surface charge at various porosities and ionic conditions. Pore parameters strongly affected the average internal charge which we characterized as a function of overlap ratio and porosity, first time in literature. Using this, a phenomenological model was developed as an extension of the existing theory to include nano-effects, to predict the average mesoporous internal surface charge as a function of EDL thickness, pore size and porosity.
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Affiliation(s)
- Tumcan Sen
- Department of Mechanical Engineering, Izmir Institute of Technology, Izmir, 35430, Turkey
| | - Murat Barisik
- Department of Mechanical Engineering, Izmir Institute of Technology, Izmir, 35430, Turkey.
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Ozcelik HG, Barisik M. Electric charge of nanopatterned silica surfaces. Phys Chem Chem Phys 2019; 21:7576-7587. [DOI: 10.1039/c9cp00706g] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The surface charge density of a nanopatterned silica decreased at the pits but increased at the tips of surface patterns. For a case of self-repeating surface structures, the average of local surface charges becomes lower than the theoretical predictions. Our phenomenological model developed as an extension to the existing flat surface theory predicts the average surface charge on a nanopatterned surface as a function of surface pattern size, ionic concentration and pH.
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Affiliation(s)
- H. Gokberk Ozcelik
- Department of Mechanical Engineering
- Izmir Institute of Technology
- IZMIR
- Turkey
| | - Murat Barisik
- Department of Mechanical Engineering
- Izmir Institute of Technology
- IZMIR
- Turkey
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