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Braile D, Hare C, Wu CY. DEM analysis of swelling behaviour in granular media. ADV POWDER TECHNOL 2022. [DOI: 10.1016/j.apt.2022.103806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Chang CL, Lin WC, Ting LY, Shih CH, Chen SY, Huang TF, Tateno H, Jayakumar J, Jao WY, Tai CW, Chu CY, Chen CW, Yu CH, Lu YJ, Hu CC, Elewa AM, Mochizuki T, Chou HH. Main-chain engineering of polymer photocatalysts with hydrophilic non-conjugated segments for visible-light-driven hydrogen evolution. Nat Commun 2022; 13:5460. [PMID: 36115857 PMCID: PMC9482619 DOI: 10.1038/s41467-022-33211-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 09/07/2022] [Indexed: 11/10/2022] Open
Abstract
Photocatalytic water splitting is attracting considerable interest because it enables the conversion of solar energy into hydrogen for use as a zero-emission fuel or chemical feedstock. Herein, we present a universal approach for inserting hydrophilic non-conjugated segments into the main-chain of conjugated polymers to produce a series of discontinuously conjugated polymer photocatalysts. Water can effectively be brought into the interior through these hydrophilic non-conjugated segments, resulting in effective water/polymer interfaces inside the bulk discontinuously conjugated polymers in both thin-film and solution. Discontinuously conjugated polymer with 10 mol% hexaethylene glycol-based hydrophilic segments achieves an apparent quantum yield of 17.82% under 460 nm monochromatic light irradiation in solution and a hydrogen evolution rate of 16.8 mmol m−2 h−1 in thin-film. Molecular dynamics simulations show a trend similar to that in experiments, corroborating that main-chain engineering increases the possibility of a water/polymer interaction. By introducing non-conjugated hydrophilic segments, the effective conjugation length is not altered, allowing discontinuously conjugated polymers to remain efficient photocatalysis. The introduction of hydrophilic segments into the main-chain of polymer photocatalysts allows water to efficiently enter the interior through these hydrophilic segments, and results in effective water/polymer interfaces for hydrogen evolution.
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Abstract
Swelling of grains due to water absorption is ubiquitous in many natural materials and industrial products. Hence, a thorough understanding of grain swelling is of great scientific importance. An experimental investigation can only provide limited information, whereas great insight could be gained from numerical modelling, rigorous numerical models for describing particle swelling are essential. Thus, the objective of this study is to develop and validate a discrete element method (DEM) model for swelling of grains. A first order kinetic model was introduced to describe the swelling of a single grain, and subsequently implemented into the DEM code LIGGGHTS. Model validation was performed by comparing the time evolution of the expansion of a packed bed made of super absorbent polymer (SAP) particles obtained numerically and experimentally. It was demonstrated that the developed model can accurately predict the bed expansion. The validated model was then used to investigate the effect of material properties on the swelling behaviour using rice and SAP as the model materials. It is shown that the swelling depends significantly on material properties, as expected; the expansion of the powder bed made of rice is much lower than that of SAP. The developed model could be further advanced to study consequences of swelling phenomena in granular materials, such as segregation and heat generation.
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Abstract
The swelling effect in hydrogel bodies or sponge-like porous bodies (SPB) used in a specific stormwater storage concept of the down-flow type is considered. A macroscopic swelling model is proposed, in which water is assumed to penetrate into the hydrogel by diffusion described by diffusion equations together with a free-moving boundary separating the interface between the water and hydrogel. Such a type of problem belongs to the certain class of problems called Stefan-problems. The main objective of this contribution is to compare how the theoretical total amount of absorbed water is modified by the inclusion of swelling, when compared to the previously studied SPB devices analyzed only for the effect of diffusion. The results can be summarized in terms of the geometrical dimensions of the storage device and the magnitude of the diffusion coefficient D. The geometrical variables influence both the maximum possible absorbed volume and the time to reach that volume. The diffusion coefficient D only influences the rate of volume growth and the time to reach the maximum volume of stored water. The initial swelling of the hydrogel SPB grows with time (Dt) until the steady state is reached and the swelling rate approaches zero. In all the cases considered, the swelling in general increases the maximum possible absorbed water volume by an amount of 14%.
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Santagata T, Solimene R, Aprea G, Salatino P. Modelling and experimental characterization of unsaturated flow in absorbent and swelling porous media. Chem Eng Sci 2020. [DOI: 10.1016/j.ces.2020.115765] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Soundaranathan M, Vivattanaseth P, Walsh E, Pitt K, Johnston B, Markl D. Quantification of swelling characteristics of pharmaceutical particles. Int J Pharm 2020; 590:119903. [PMID: 32980508 DOI: 10.1016/j.ijpharm.2020.119903] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/14/2020] [Accepted: 09/19/2020] [Indexed: 01/27/2023]
Abstract
Particle swelling is a crucial component in the disintegration of a pharmaceutical tablet. The swelling of particles in a tablet creates stress inside the tablet and thereby pushes apart adjoining particles, eventually causing the tablet to break-up. This work focused on quantifying the swelling of single particles to identify the swelling-limited mechanisms in a particle, i.e. diffusion- or absorption capacity-limited. This was studied for three different disintegrants (sodium starch glycolate/SSG, croscarmellose sodium/CCS, and low-substituted hydroxypropyl cellulose/L-HPC) and five grades of microcrystalline cellulose (MCC) using an optical microscope coupled with a bespoke flow cell and utilising a single particle swelling model. Fundamental swelling characteristics, such as diffusion coefficient, maximum liquid absorption ratio and swelling capacity (maximum swelling of a particle) were determined for each material. The results clearly highlighted the different swelling behaviour for the various materials, where CCS has the highest diffusion coefficient with 739.70 μm2/s and SSG has the highest maximum absorption ratio of 10.04 g/g. For the disintegrants, the swelling performance of SSG is diffusion-limited, whereas it is absorption capacity-limited for CCS. L-HPC is both diffusion- and absorption capacity-limited. This work also reveals an anisotropic, particle facet dependant, swelling behaviour, which is particularly strong for the liquid uptake ability of two MCC grades (PH101 and PH102) and for the absorption capacity of CCS. Having a better understanding of swelling characteristics of single particles will contribute to improving the rational design of a formulation for oral solid dosage forms.
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Affiliation(s)
- Mithushan Soundaranathan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK; Future Continuous Manufacturing and Advanced Crystallisation Research Hub, University of Strathclyde, Glasgow G1 1RD, UK
| | - Pattavet Vivattanaseth
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK; Future Continuous Manufacturing and Advanced Crystallisation Research Hub, University of Strathclyde, Glasgow G1 1RD, UK; School of Pharmaceutical Sciences, University of Phayao, Phayao, Thailand
| | - Erin Walsh
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK; Future Continuous Manufacturing and Advanced Crystallisation Research Hub, University of Strathclyde, Glasgow G1 1RD, UK
| | - Kendal Pitt
- Pharma Supply Chain, GlaxoSmithKline, Ware SG12 0DE, UK
| | - Blair Johnston
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK; Future Continuous Manufacturing and Advanced Crystallisation Research Hub, University of Strathclyde, Glasgow G1 1RD, UK; National Physical Laboratory, Teddington, TW11 0LW, UK
| | - Daniel Markl
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK; Future Continuous Manufacturing and Advanced Crystallisation Research Hub, University of Strathclyde, Glasgow G1 1RD, UK.
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Santagata T, Solimene R, Aprea G, Salatino P. Modelling and Experimental Characterization of Unsaturated Flow in Absorbent and Swelling Porous Media: Material Characterization. Transp Porous Media 2020. [DOI: 10.1007/s11242-020-01467-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Kiradjiev KB, Nikolakis V, Griffiths IM, Beuscher U, Venkateshwaran V, Breward CJW. A Simple Model for the Hygroscopy of Sulfuric Acid. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.9b06018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Vladimiros Nikolakis
- W. L. Gore and Associates, Inc., 100 Airport Rd, Elkton, Maryland 21921, United States
| | - Ian M. Griffiths
- Mathematical Institute, University of Oxford, Woodstock Rd, OX2 6GG Oxford, U.K
| | - Uwe Beuscher
- W. L. Gore and Associates, Inc., 100 Airport Rd, Elkton, Maryland 21921, United States
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Mahmoodi-Babolan N, Nematollahzadeh A, Heydari A, Merikhy A. Bioinspired catecholamine/starch composites as superadsorbent for the environmental remediation. Int J Biol Macromol 2019; 125:690-699. [PMID: 30529207 DOI: 10.1016/j.ijbiomac.2018.12.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 11/16/2018] [Accepted: 12/02/2018] [Indexed: 01/04/2023]
Abstract
Focusing on the encouraging properties of starch-based composite materials, starch‑g‑(acrylic acid‑co‑acrylamide) superabsorbent was synthesized using solution polymerization method, and then the catecholamine functional groups were introduced on to pore surface of the absorbent via oxidative polymerization of dopamine (DA). The adsorbent was optimized in terms of the monomers' mass ratio and synthesis conditions, and characterized by different characterization techniques. The polydopamine (PDA) coating thickness was estimated using transmission electron microscopy (TEM) image and it was found to be 83 nm. The bimodal mesoporous adsorbent with 5914.66% swelling ratio bearing micropores with a specific surface area of 2.8031 m2 g-1 was used for the adsorption of methylene blue (MB) as a model water pollutant dye. The maximum adsorption capacity was obtained 2276 mg g-1 at pH 9 and within 100 min. The adsorbent with unprecedented super high adsorption capacity can be encouraging from different environmental remediation points of view.
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Affiliation(s)
- Negin Mahmoodi-Babolan
- Chemical Engineering Department, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil, Iran
| | - Ali Nematollahzadeh
- Chemical Engineering Department, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil, Iran.
| | - Amir Heydari
- Chemical Engineering Department, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil, Iran
| | - Arezoo Merikhy
- Chemical Engineering Department, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil, Iran
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