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

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.

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

Membranes ◽

10.3390/membranes11070532 ◽

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.

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A COMPARISON BETWEEN VARIOUS HYBRID SYSTEMS OF MICROFILTRATION MEMBRANE AND BACTERIA FOR REMOVAL OF ORGANIC COMPOUNDS

Chemical Engineering Communications ◽

10.1080/00986440903412993 ◽

2010 ◽

Vol 197 (8) ◽

pp. 1057-1067

Author(s):

S. S. Madaeni ◽

M. Zarbakhsh

Keyword(s):

Hybrid Systems ◽

Organic Compounds ◽

Microfiltration Membrane

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Catalytic ozonation of model organic compounds in aqueous solution promoted by metallic oxides

Desalination and Water Treatment ◽

10.1080/19443994.2013.860630 ◽

2013 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Lobna Mansouri ◽

Marina Sabelfeld ◽

Sven-Uwe Geissen ◽

Latifa Bousselmi

Keyword(s):

Aqueous Solution ◽

Organic Compounds ◽

Catalytic Ozonation ◽

Metallic Oxides

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Catalytic ozonation—Effect of carbon contaminants on the process of ozone decomposition

Applied Catalysis B Environmental ◽

10.1016/j.apcatb.2013.05.028 ◽

2013 ◽

Vol 142-143 ◽

pp. 307-314 ◽

Cited By ~ 14

Author(s):

Jacek Nawrocki ◽

Lilla Fijołek

Keyword(s):

Catalytic Ozonation ◽

Ozone Decomposition

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Evaluation of Tanzania local ceramic raw materials for high voltage porcelain insulators production

Cerâmica ◽

10.1590/0366-69132018643722427 ◽

2018 ◽

Vol 64 (372) ◽

pp. 570-576

Author(s):

B. Ngayakamo ◽

S. E. Park

Keyword(s):

High Voltage ◽

Bending Strength ◽

Raw Materials ◽

Microstructural Characterization ◽

Dielectric Strength ◽

Pressing Method ◽

X Ray ◽

Mineral Phases ◽

Porcelain Insulators ◽

High Voltage Porcelain

Abstract This study evaluated the potential of locally sourced-ceramic raw materials in Tanzania, Pugu kaolin, Same clay, vermiculite and feldspar, for production of high voltage porcelain insulators. The chemical, mineral phases and microstructural characterization of raw materials and porcelain samples were carried out using the X-ray fluorescence, X-ray diffraction, and scanning electron microscopy techniques, respectively. The mineral phases of the fired porcelain sample identified were mullite and quartz. The porcelain bodies were fabricated using the dry pressing method by varying the composition of the selected ceramic raw materials. The physical-mechanical properties and dielectric strength were measured for each porcelain sample. The sample with the composition of 20% Pugu kaolin, 20% Same clay, 20% vermiculite and 40% feldspar was found to have the dielectric strength of 50.8 kV.mm-1, bending strength of 20 MPa and water absorption of 0.46%, which satisfies the main requisite properties for high voltage porcelain insulators.

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USING METAL WASTE SLAGS AS THE HETEROGENEOUS CATALYSTS OF OZONE FOR TREATMENT OF PULP WASTEWATER

Vietnam Journal of Science and Technology ◽

10.15625/2525-2518/58/3a/14227 ◽

2020 ◽

Vol 58 (3A) ◽

pp. 1

Author(s):

Hu Tap Van

Keyword(s):

Organic Compounds ◽

Removal Efficiency ◽

Heterogeneous Catalysts ◽

Catalytic Ozonation ◽

Cod Removal ◽

Color Removal ◽

Order Kinetic ◽

First Order ◽

Iron Slag ◽

Ozonation Process

Catalytic ozonation is one of the promising treatment methods for removal of persistent organic compounds from water and wastewater. In this study, some metal slags such as: iron slag, lead slag, zinc slag, cadmium slag and copper slag originated from solid waste of Thai Nguyen Non-ferrous Metals Limited Company, Vietnam were used as heterogeneous catalysts for ozonation process to remove organic compounds from pulp wastewater. The effects of the initial pH (pHi) of pulp wastewater and the metal slag dosage on efficiency of decolorization and mineralization of pulp wastewater, in term of COD were investigated. The results indicated that iron slag was the most suitable catalyst for treatment of pulp wastewater by ozonation process with the highest removal efficiency of COD, namely, after 120 min of ozonation (with flowrate of O3 of 3.038 g/h) of the pulp wastewater (initial COD 1809 mg/L), COD removal efficiency, respectively, reached 91,16%; 84%; 83,83 %; 83,91%; 83,41% and 83,14% in the presence of iron, copper, zinc, lead, cadmium slag and ozone alone. Simultaneously, the color was almost completely removed (95.55 – 98.79%) by ozonation processes with using all before-mentioned metal slags as heterogeneous catalysts and ozone alone. Maximum COD and color removal efficiency obtained at pH 7 for ozonation alone and its combinations with iron slag. Moreover, an increase in the iron slag dosage from 0.125 g/L to 2.0 g/L for O3/iron slag could enhance COD and color removal of pulp wastewater. The K values (apparent first-order rate constant values) showed that the COD removal rate followed the pseudo-first-order kinetic model. This study also indicated that the main constituent FeO presence in iron slag reaction with O3 in heterogeneous catalytic ozonation system enhances removal efficiency of color and COD of pulp wastewater.

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Combined air-water flush in dead-end ultrafiltration

Water Science & Technology Water Supply ◽

10.2166/ws.2001.0139 ◽

2001 ◽

Vol 1 (5-6) ◽

pp. 393-402 ◽

Cited By ~ 3

Author(s):

J.Q.J.C. Verbeck ◽

G.I.M. Worm ◽

H. Futselaar ◽

J.C. van Dijk

Keyword(s):

Membrane Surface ◽

Head Loss ◽

Direct Result ◽

Two Phase ◽

Sand Filters ◽

Membrane Pores ◽

Dead End ◽

Pre Treatment ◽

A New Technique ◽

Energy Dissipated

Dead-end ultrafiltration has proven itself as a technique for reclamation of backwash water of sand filters and as a pre-treatment step for spiral wound reverse osmosis. A direct result of dead-end filtration is a decreased flux caused by the accumulation of material in the membrane pores and on the membrane surface. Different cleaning techniques are used to remove this accumulated material. Recently a new technique has been introduced, the AirFlush. This technique makes use of air to create higher turbulence as compared to a water flush. At Delft University of Technology research has started into the fundamentals of the combined air- and water-flush. First a series of experiments has been carried out to determine the different flow patterns, followed by experiments to determine which air- and water-velocities give the best cleaning. Finally head loss experiments have been done to get information about the energy dissipated in the system. The results of the head loss experiments have been compared to the theoretical head loss calculated with the theory of heterogeneous two-phase flow.

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Reduction of Biofouling of a Microfiltration Membrane Using Amide Functionalities—Hydrophilization without Changes in Morphology

Polymers ◽

10.3390/polym12061379 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1379

Author(s):

Daniel Breite ◽

Marco Went ◽

Andrea Prager ◽

Mathias Kühnert ◽

Agnes Schulze

Keyword(s):

Membrane Fouling ◽

Average Pore Size ◽

Membrane Surface ◽

Aqueous Media ◽

Soxhlet Extraction ◽

Hydrophobic Membrane ◽

Average Pore ◽

Water Contact ◽

Microfiltration Membrane ◽

Membrane Performance

A major goal of membrane science is the improvement of the membrane performance and the reduction of fouling effects, which occur during most aqueous filtration applications. Increasing the surface hydrophilicity can improve the membrane performance (in case of aqueous media) and decelerates membrane fouling. In this study, a PES microfiltration membrane (14,600 L m−2 h−1 bar−1) was hydrophilized using a hydrophilic surface coating based on amide functionalities, converting the hydrophobic membrane surface (water contact angle, WCA: ~90°) into an extremely hydrophilic one (WCA: ~30°). The amide layer was created by first immobilizing piperazine to the membrane surface via electron beam irradiation. Subsequently, a reaction with 1,3,5-benzenetricarbonyl trichloride (TMC) was applied to generate an amide structure. The presented approach resulted in a hydrophilic membrane surface, while maintaining permeance of the membrane without pore blocking. All membranes were investigated regarding their permeance, porosity, average pore size, morphology (SEM), chemical composition (XPS), and wettability. Soxhlet extraction was carried out to demonstrate the stability of the applied coating. The improvement of the modified membranes was demonstrated using dead-end filtration of algae solutions. After three fouling cycles, about 60% of the initial permeance remain for the modified membranes, while only ~25% remain for the reference.

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Tensile and Bending Strength Improvements in PEEK Parts Using Fused Deposition Modelling 3D Printing Considering Multi-Factor Coupling

Polymers ◽

10.3390/polym12112497 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2497 ◽

Cited By ~ 1

Author(s):

Yao Li ◽

Yan Lou

Keyword(s):

Tensile Strength ◽

3D Printing ◽

Tensile Properties ◽

Bending Strength ◽

Utilization Rate ◽

Fused Deposition Modelling ◽

Fused Deposition ◽

Molded Parts ◽

Injection Molded ◽

Printing Direction

Compared with laser-based 3D printing, fused deposition modelling (FDM) 3D printing technology is simple and safe to operate and has a low cost and high material utilization rate; thus, it is widely used. In order to promote the application of FDM 3D printing, poly-ether-ether-ketone (PEEK) was used as a printing material to explore the effect of multi-factor coupling such as different printing temperatures, printing directions, printing paths, and layer thicknesses on the tensile strength, bending strength, crystallinity, and grain size of FDM printed PEEK parts. The aim was to improve the mechanical properties of the 3D printed PEEK parts and achieve the same performance as the injection molded counterparts. The results show that when the thickness of the printed layer is 0.1 mm and the printing path is 180° horizontally at 525 °C, the tensile strength of the sample reaches 87.34 MPa, and the elongation reaches 38%, which basically exceeds the tensile properties of PEEK printed parts reported in previous studies and is consistent with the tensile properties of PEEK injection molded parts. When the thickness of the printed layer is 0.3 mm, the printing path is 45°, and with vertical printing direction at a printing temperature of 525 °C, the bending strength of the sample reaches 159.2 MPa, which exceeds the bending performance of injection molded parts by 20%. It was also found that the greater the tensile strength of the printed specimen, the more uniform the size of each grain, and the higher the crystallinity of the material. The highest crystallinity exceeded 30%, which reached the crystallinity of injection molded parts.

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