scholarly journals Fabrication of Cementitious Microfiltration Membrane and Its Catalytic Ozonation for the Removal of Small Molecule Organic Pollutants

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 532
Author(s):  
Jingyi Sun ◽  
Shan Liu ◽  
Jing Kang ◽  
Zhonglin Chen ◽  
Liming Cai ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Organic Pollutants ◽  
Small Molecule ◽  
Bending Strength ◽  
Catalytic Ozonation ◽  
Coupling Process ◽  
Microfiltration Membrane

In this study, a low-cost cementitious microfiltration membrane (CM) with a catalytic ozone oxidation function for the removal of organic pollutants was fabricated by using cementitious and C-10 μm silica powders at a certain silica–cementitious particle ratio (s/c). The effect of the s/c on the pore size distribution and mechanical strength of the membrane was investigated. The membrane pore size showed a bimodal distribution, and the higher the s/c, the closer the second peak was to the accumulated average particle size of silica. The increase in the s/c led to a decrease in the bending strength of the membrane. The cross-sectional morphology by SEM and crystal structure by XRD of CMs confirmed that a calcium silicate hydrate gel was generated around the silica powder to improve the mechanical strength of the CM. Considering the bending strength and pore size distribution of CMs, s/c = 0.5 was selected as the optimal membrane fabrication condition. The FT-IR results characterizing the surface functional groups of CMs were rich in surface hydroxyl groups with the ability to catalyze ozone oxidation for organic pollutant removal. Six small molecule organic pollutants were selected as model compounds for the efficiency experiments via a CM‒ozone coupling process to prove the catalytic property of the CM. The CM has an alkaline buffering effect and can stabilize the initial pH of the solution in the catalytic ozonation process. The reuse experiments of the CM‒ozone coupling process demonstrated the broad spectrum of the CM catalytic performance and self-cleaning properties. The results of this study provide the basis and experimental support to expand the practical application of CMs.

scholarly journals Innovative Material Can Mimic Coral and Boulder Reefs Properties

2021 ◽  
Vol 8 ◽  
Author(s):  
Lucia Margheritini ◽  
Per Møldrup ◽  
Rasmus Lund Jensen ◽  
Kirstine Meyer Frandsen ◽  
Yovko Ivanov Antonov ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Low Voltage ◽  
Artificial Reef ◽  
Total Porosity ◽  
Electrical Current ◽  
High Porosity ◽  
Mineral Deposition

Low-Voltage Mineral Deposition technology (LVMD), widely known as Biorock, has previously been suggested as support for coral reef restoration, as hypothesized high porosity, wide pore-size distribution and connectivity, and good strength properties may facilitate biological functions (for example larvae settlement) and durability. In this technology, very low voltage induces an electrical current that initiates precipitation and accretion of hard minerals (aragonite and calcite) on a metal in seawater. This technology has been discussed mainly for its biological value, while this paper wants to highlight also its engineering value as artificial reef material. Indeed, some of the properties that makes it valuable in one domain are also supporting its use in the other. Because the metal on which the precipitation takes place can be of any shape and size, so can the artificial reef and its mechanical strength characteristics are above the ones of corals and similar to concrete, indicating adequate durability. Coral and boulder reefs suffering from degradation have severe implications on biodiversity, protection from flooding, and cultural value and therefore understanding how to persevere and re-establish these ecosystems is central for sustainable intervention in the marine environment. By comparing chemical-physical characteristics of Coral Porites Exoskeleton (CPE), one typical reef building coral type, LVMD and High-Voltage Mineral Deposition (HVMD), we show that they possess highly similar properties including chemical composition, density, total porosity, pore-size distribution, physical and chemical heterogeneity, total and external surface areas, and comparable mechanical strength.

Effect of UF/Epoxy Microcapsules on Cement Composite

2012 ◽  
Vol 443-444 ◽  
pp. 700-704 ◽  
Author(s):  
Zhuo Ni ◽  
Xue Xiao Du ◽  
Shuai Wang ◽  
Feng Xing ◽  
Zhan Huang
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Bending Strength ◽  
Cement Composite ◽  
Cement Composites ◽  
Self Healing ◽  
Thermal Techniques ◽  
Designed Materials

Effect of microcapsules on cement composites has been studied. The hydration of cement composite using microcapsules is studied by XRD and thermal techniques, showing that the addition of microcapsules has little affect on the hydration of cement. The pore size distribution and surface area of the cement composite with microcapsule are analyzed, showing a reduction in the pore content of cement composite and makes the pores smaller, which would improve durability and impermeability for designed materials. Damaging on cement and composites containing microcapsules and self-healing of these damagings can be reflected by the changes in their bending strength. When the cracks were generated in the composite, the microcapsules can release adhesive to fill in the space between the crackings, preventing cracking further growth.

scholarly journals A Comparative Study on the Addition Methods of TiO2 Sintering Aid to the Properties of Porous Alumina Membrane Support

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 49 ◽  
Author(s):  
Yulong Yang ◽  
Qibing Chang ◽  
Zhiwen Hu ◽  
Xiaozhen Zhang
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Bending Strength ◽  
Porous Alumina ◽  
Alumina Membrane ◽  
Sintering Aid ◽  
Hydrolysis Method ◽  
Porous Alumina Membrane

TiO2 is usually used as a sintering aid to lower the sintering temperature of porous alumina membrane support. Two ways of the addition of TiO2 are chosen: in-situ precipitation and in-situ hydrolysis. The results show that the distribution status of TiO2 has an important effect on the property of porous alumina membrane support. In in-situ hydrolysis method, the nano-meter scale TiO2 distributes evenly on the alumina particles’ surface. The bending strength of the support increases sharply and the pore size distribution changes more sharply along with the content of TiO2 which slightly increases from 0.3 wt.% to 0.4 wt.%. The distribution of the nano-meter scale TiO2 is not so even added by in-situ precipitation method. Neither the bending strength nor the pore size distribution of the support is worse than that of the support added by in-situ hydrolysis even if the content of TiO2 is high to 2 wt.%. The permeating flux has a similar tendency. Consequently, the porous alumina membrane support has the porosity of 30.01% and the bending strength of 77.33 MPa after sintering at 1650 °C for 2 h with the optimized TiO2 content of 0.4 wt.% added by the in-situ hydrolysis method.

scholarly journals Catalytic Efficiency of Carbon-Cementitious Microfiltration Membrane on the Ozonation-Based Oxidation of Small Molecule Organic Compounds and Its Alkaline Buffering Effect in Aqueous Solution

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 601
Author(s):  
Jingyi Sun ◽  
Zhonglin Chen ◽  
Shan Liu ◽  
Jing Kang ◽  
Yuhao Guo ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Bending Strength ◽  
Membrane Surface ◽  
Catalytic Ozonation ◽  
Utilization Rate ◽  
Ozone Decomposition ◽  
Pressing Method ◽  
Coupling Process ◽  
Microfiltration Membrane ◽  
Membrane Pores

In this study, powdered activated carbon (PAC) was added to replace the silica in a cementitious microfiltration membrane (CM) to solve the problems of the low mechanical strength and short lifetime of CMs. The carbon-cementitious microfiltration membrane (CCM) was fabricated by the dry pressing method and cured at room temperature. The bending strength of CCM was 12.69 MPa, which was about three times more than that of CM. The average pore size was 0.129 μm, and was reduced by about 80% compared to that of CM. The addition of PAC did not reduce the degradation efficiency of membrane catalytic ozonation. Because of the strong alkaline buffering ability of CCM, the CCM–ozone coupling process could eliminate the effect of the pH value of the solution. The strong alkaline environment inside the membrane pores effectively accelerated the ozone decomposition and produced oxidizing radicals, which accelerated the reaction rate and improved the utilization rate of ozone. The CCM–catalytic ozonation reaction of organic compounds occurred within the pores and membrane surface, resulting in the pH of the solution belonging to the neutral range. The addition of PAC accelerated the mass transfer and made the pollutants and oxidant react in the membrane pores and on the membrane surface. The reuse experiments of the CCM–ozone coupling process for removing nitrobenzene demonstrated that CCM has good catalytic activity and reuse stability. It broadens the application scope of CCM in the field of drinking water and provides theoretical support for the practical application of CCM.

pyGAPS: A Python-Based Framework for Adsorption Isotherm Processing and Material Characterisation

2019 ◽  
Author(s):  
Paul Iacomi ◽  
Philip L. Llewellyn
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Isosteric Heat ◽  
Material Characterisation ◽  
Mixture Adsorption ◽  
Surface Energetics ◽  
Adsorption Processing ◽  
User Friendly

Material characterisation through adsorption is a widely-used laboratory technique. The isotherms obtained through volumetric or gravimetric experiments impart insight through their features but can also be analysed to determine material characteristics such as specific surface area, pore size distribution, surface energetics, or used for predicting mixture adsorption. The pyGAPS (python General Adsorption Processing Suite) framework was developed to address the need for high-throughput processing of such adsorption data, independent of the origin, while also being capable of presenting individual results in a user-friendly manner. It contains many common characterisation methods such as: BET and Langmuir surface area, t and α plots, pore size distribution calculations (BJH, Dollimore-Heal, Horvath-Kawazoe, DFT/NLDFT kernel fitting), isosteric heat calculations, IAST calculations, isotherm modelling and more, as well as the ability to import and store data from Excel, CSV, JSON and sqlite databases. In this work, a description of the capabilities of pyGAPS is presented. The code is then be used in two case studies: a routine characterisation of a UiO-66(Zr) sample and in the processing of an adsorption dataset of a commercial carbon (Takeda 5A) for applications in gas separation.

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