Porous PDMS structures for the storage and release of aqueous solutions into fluidic environments

Lab on a Chip ◽  
2017 ◽  
Vol 17 (14) ◽  
pp. 2517-2527 ◽  
Author(s):  
Peter Thurgood ◽  
Sara Baratchi ◽  
Crispin Szydzik ◽  
Arnan Mitchell ◽  
Khashayar Khoshmanesh
Keyword(s):  
Aqueous Solutions ◽  
Building Block ◽  
Microfluidic Systems ◽  
Passive Release ◽  
Highly Porous

This work introduces a highly porous PDMS sponge for the storage and passive release of aqueous solutions, acting as a building block for self-sufficient microfluidic systems.

scholarly journals Adsorption of Cu(II) from aqueous solution using raw peat: preliminary results

2019 ◽  
Vol 98 ◽  
pp. 06010 ◽  
Author(s):  
Olga Naymushina ◽  
Olga Gaskova
Keyword(s):  
Aqueous Solutions ◽  
Active Sites ◽  
West Siberia ◽  
Maximum Adsorption Capacity ◽  
Adsorption Data ◽  
Removal Of Heavy Metals ◽  
Freundlich Adsorption Isotherm ◽  
Time Variations ◽  
Highly Porous ◽  
Highly Porous Material

Peat is a polar, highly porous material that could have significant applications as an adsorbent for removal of heavy metals from aqueous solutions. Various functional groups in lignin allow such compounds to bind on active sites of peat. The adsorption of Cu (II) from aqueous solutions on peat from the West Siberia was studied in the concentration range of 10–150 mg/L and time variations of 0.25-12 hours. The pH of the solutions varied over a range of 3.2–4.3. The adsorption data could be fitted to a Freundlich adsorption isotherm and the maximum adsorption capacity of peat was determined to be 2.5⋅10-3 mmol/g when the initial concentration for Cu2+ was at its minimum (0.05 mmol/L), and the time of adsorption was 30 minutes.

Replacement of anhydrite by hydroxyapatite: kinetic and textural characteristics

2020 ◽  
Author(s):  
Ana Roza ◽  
Amalia Jiménez ◽  
Lurdes Fernández-Díaz
Keyword(s):  
Aqueous Solutions ◽  
Molar Volume ◽  
Sedimentary Basins ◽  
Rietveld Analysis ◽  
Calcium Sulphate ◽  
Wide Range ◽  
Polycrystalline Aggregates ◽  
Diagenetic Evolution ◽  
Inner Region ◽  
Highly Porous

<p>Interface-coupled dissolution-precipitation (ICDP) reactions lead to the pseudomorphic replacement of minerals in a wide range of geological settings, exerting a significant impact in geochemical cycles (Putnis 2002). ICDP reactions play a major role in the diagenetic evolution of sedimentary rocks, specially of limestones and evaporites. Recent experimental works have studied ICDP reactions that lead to the formation of CaCO<sub>3</sub> pseudomorphs after anhydrite (CaSO<sub>4</sub>), upon interaction of the latter phase with carbonated aqueous solutions. These pseudomorphs are highly porous polycrystalline aggregates that mainly consist of calcite (Roncal-Herrero et al. 2018; Altree-Williams et al. 2017). The formation of a large volume of interconnected microporosity that balances the molar volume loss associated to the anhydrite-calcite transformation as well as the specific arrangement of this microporosity, influenced by the existence of epitactic relationships between anhydrite and calcite, facilitate the progress of the ICDP reaction.</p><p>Here, we study the ICDP reaction that leads to the formation of hydroxyapatite (Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>(OH)) pseudomorphs after the interaction of anhydrite with phosphate-bearing aqueous solutions at temperatures 90 to180ºC during times that range from one hour to five weeks. The X-ray diffraction Rietveld analysis of the transformed samples indicates that the kinetics of the pseudomorphic transformation of anhydrite into hydroxyapatite strongly depends on temperature.  Thus, while at 180ºC a 100% transformation yield is attained in few hours, it takes five weeks of interaction at 90ºC. Scanning Electron Microscopy imagining of transformed samples shows the very good preservation of both, the original external shape and microtopographic features of anhydrite crystals. On cross-cut sections of partially replaced by hydroxyapatite anhydrite crystals we observe that the transformation advances from the surface inwards, with sharp separating the by replaced layer from the unreacted anhydrite core. Furthermore, this replaced layer is structured into a compact ~ 50 µm thick outer rim, which consists of coalescent small (~ 5 µm) hydroxyapatite crystals, and a progressively thickening inner region formed by hydroxyapatite columnar crystals in a stockade-like arrangement. This latter region is highly porous. We interpret these results taking into consideration the differences in solubility and molar volume between anhydrite and hydroxyapatite as well as the similarities/differences between the crystal structures of these phases. By comparing the characteristics of different ICDP reactions that involve anhydrite in sedimentary basins we derive implications about the diagenetic evolution of calcium sulphate evaporites. </p><p> </p><p>Altree-Williams, Alexander, et al. (2017). <em>ACS Earth and Space Chemistry</em> 1.2, 89-100.</p><p>Roncal-Herrero, Teresa, et al. (2017): <em>American Mineralogist</em> 102.6, 1270-1278.</p><p>Putnis A: (2002): <em>Mineralogical Magazine</em> 66.5, 689-708.</p><p> </p><p> </p>

Aerocellulose: New Highly Porous Cellulose Prepared from Cellulose−NaOH Aqueous Solutions

2008 ◽  
Vol 9 (1) ◽  
pp. 269-277 ◽  
Author(s):  
Roxane Gavillon ◽  
Tatiana Budtova
Keyword(s):  
Aqueous Solutions ◽  
Highly Porous

scholarly journals A Method for Simultaneous Polishing and Hydrophobization of Polycarbonate for Microfluidic Applications

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2490
Author(s):  
Dominika Ogończyk ◽  
Paweł Jankowski ◽  
Piotr Garstecki
Keyword(s):  
Aqueous Solutions ◽  
Chemical Polishing ◽  
Optical Transparency ◽  
Cross Contamination ◽  
Surface Rendering ◽  
Microfluidic Systems ◽  
Two Phase

Here we present a new methodology for chemical polishing of microchannels in polycarbonate (PC). Tuning the time of exposition and the concentration of ammonia, the roughness arising from the micromachining process can be significantly reduced or completely removed while preserving the structure of microchannels. Besides smoothing out the surface, our method modifies the wettability of the surface, rendering it hydrophobic. The method increases the optical transparency of microchannels and eliminates undesired effects in two-phase microfluidic systems, including wetting by aqueous solutions and cross-contamination between aqueous droplets that could otherwise shed satellites via pinning.

Application of highly porous materials for simazine removal from aqueous solutions

2016 ◽  
Vol 37 (19) ◽  
pp. 2428-2434 ◽  
Author(s):  
Serena Esposito ◽  
Edoardo Garrone ◽  
Antonello Marocco ◽  
Michele Pansini ◽  
Paola Martinelli ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Porous Materials ◽  
Highly Porous Materials ◽  
Highly Porous

Thermoplastic building blocks for the fabrication of microfluidic masters

RSC Advances ◽  
2015 ◽  
Vol 5 (119) ◽  
pp. 97934-97943 ◽  
Author(s):  
Michael A. Stoller ◽  
Abhiteja Konda ◽  
Matthew A. Kottwitz ◽  
Stephen A. Morin
Keyword(s):  
Rapid Prototyping ◽  
Building Block ◽  
Building Blocks ◽  
Microfluidic Systems ◽  
Block Based

This manuscript reports a building-block-based approach for the design and fabrication of masters that enables “ultra-rapid” prototyping of functional microfluidic systems.

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