scholarly journals Clay Hybrid Membranes in Wastewater Treatment

2021 ◽  
Author(s):  
Tanushree Choudhury

Most of NF membranes which are developed recently are composite membranes, whose support layer is covered with an active layer. Among different ceramic support materials that are currently used as support layer, α-alumina supports are integral part of the membrane which is made of artificial materials like alumina and thus adds to the high price of the membrane. This draws our attention in making low cost support material of natural clay which aims to be an excellent membrane support as it possesses high mechanical strength, high permeability, narrow pore size distribution and low manufacturing cost. Titania as active layer for ceramic membrane is preferred over Al2O3 membranes. One of the problems encountered when photocatalysts are immobilized on support is the detachment of the micro particles from the support for high flow rates of liquid effluent. This can be overcome by using Montmorillonite clay as support material as it is a great binder.


2019 ◽  
Author(s):  
Moritz Wolf ◽  
Nico Fischer ◽  
Michael Claeys

<p>The inert nature of graphitic samples allows for characterisation of rather isolated supported nanoparticles in model catalysts, as long as sufficiently large inter-particle distances are obtained. However, the low surface area of graphite and the little interaction with nanoparticles result in a challenging application of conventional preparation routes in practice. In the present study, a set of graphitic carbon materials was characterised in order to identify potential support materials for the preparation of model catalyst systems. Various sizes of well-defined Co<sub>3</sub>O<sub>4</sub> nanoparticles were synthesised separately and supported onto exfoliated graphite powder, that is graphite after solvent-assisted exfoliation <i>via</i> ultrasonication resulting in thinner flakes with increased specific surface area. The developed model catalysts are ideally suited for sintering studies of isolated nano-sized cobaltous particles as the graphitic support material does not provide distinct metal-support interaction. Furthermore, the differently sized cobaltous particles in the various model systems render possible studies on structural dependencies of activity, selectivity, and deactivation in cobalt oxide or cobalt catalysed reactions.</p>







1991 ◽  
Vol 246 ◽  
Author(s):  
Ir. J. Van Humbeeck

AbstractA more systematic marketing research approach has finally revealed good ideas anticipating a market need for the use of shape memory alloys. The success of those new ideas, prototypes and applications are analysed in terms of “the value of the function”, defined as the importance of the function divided by the cost of providing the function. A high importance and/or a low cost of the function are thus the basic requirements for the successful introduction of shape memory applications. Attention is also paid to the way how the 4 P's, product, price, place, promotion (the marketing mix) are applied by the European companies. Those different items will be illustrated on the basis of some small-, medium- and largescale applications, used in different markets. “to the point research”, fundamental and applied, on material properties as well as on manufacturing (cost reduction) is being discussed as the key factor to increase the function value.



2021 ◽  
Vol 02 (01) ◽  
Author(s):  
Siti Khadijah Hubadillah ◽  
◽  
Norsiah Hami ◽  
Nurul Azita Salleh ◽  
Mohd Riduan Jamalludin ◽  
...  

The purpose of this work is to study the effect of kaolin particle size for the preparation of low cost ceramic membrane suspension and ceramic membrane structure. Kaolin particle size is categorized into two categories; i) ≤ 1µm and ii) ≥ 1 µm. The suspension is prepared via stirring technique under 1000 rpm at 60°C. The particle size of kaolin is characterized using field emission scanning electron microscope (FESEM) and the prepared suspension is characterized in term of its viscosity. Results indicate that the particle size gave significant effect to the viscosity of ceramic membrane suspension. Preliminary data showed that kaolin with particle size ≤ 1µm resulted ceramic membrane with dense structure.



Author(s):  
Shuo Wang ◽  
Peter Shankles ◽  
Scott Retterer ◽  
Yong Tae Kang ◽  
Chang Kyoung Choi

Abstract Opto-microfluidic methods have advantages for manufacturing complex shapes or structures of micro particles/hydrogels. Most of these microfluidic devices are made of polydimethylsiloxane (PDMS) by soft lithography because of its flexibility of designing and manufacturing. However, PDMS scatters ultraviolet (UV) light, which polymerizes the photocrosslinkable materials at undesirable locations and clogs the microfluidic devices. A fluorescent dye has previously been employed to absorb the scattered UV light and shift its wavelength to effectively solve this issue. However, this method is limited due to the cost of the materials (tens of dollars per microchip), the time consumed on synthesizing the fluorescent material and verifying its quality (two to three days). More importantly, significant expertise on material synthesis and characterization is required for users of the opto-microfluidic technique. The cost of preliminary testing on multiple iterations of different microfluidic chip designs would also be excessive. Alternatively, with a delicate microchannel design, we simply inserted aluminum foil strips (AFS) inside the PDMS device to block the scattered UV light. By using this method, the UV light was limited to the exposure region so that the opto-microfluidic device could consistently generate microgels longer than 6 h. This is a nearly cost- and labor-free method to solve this issue.



2015 ◽  
Vol 5 (2) ◽  
pp. 33-38
Author(s):  
Quang Thai Le ◽  
Minh Tuan Pham ◽  
Nguyen Quynh Trinh ◽  
Khac Tuan Vu ◽  
Hong Ha Nguyen ◽  
...  

Ion exchange is one of the most popular techniques for recovery and purification of uranium from sulfuric acid leaching solution, especially for recovery of uranium from a low uranium containing solutions. Resins commonly used are strong base or weak base anion resins with amine functional group. The anionic form of resins may be NO3-, Cl- , SO­42- or OH-. The selection of  a resin depends on the uranium total exchange capacity, selectivity and the cost. The previous studies often use Amberlite IRA-420 for concentration and purification of uranium solution from Pa Lua sandstone ores. This is a good and suitable resin but high price. To diversify the resins and reduce the costs, instead of IRA-420, the authors tested two commercial resins Indion GS300 (India) and Purolite A400 (UK) in the processing of uranium solution from sandstone ores. The results showed that the uranium total exchange capacity of  these resins is only about 80 - 85% over  Amberlite IRA-420, but these resins should be able to be used instead of Amberlite IRA-420 due to their low cost and availability in Vietnam.



Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 711
Author(s):  
Wan Fan ◽  
Dong Zou ◽  
Jingrui Xu ◽  
Xianfu Chen ◽  
Minghui Qiu ◽  
...  

Support is a necessary foundation for ceramic membranes to achieve high performance. Finding the optimum balance between high performance and low cost is still a significant challenge in the fabrication of ceramic supports. In this study, low-cost fly ash-based ceramic supports with enhanced performance were prepared by the addition of bauxite. The pore structure, mechanical strength, and shrinkage of fly ash/bauxite supports could be tuned by optimizing the bauxite content and sintering temperature. When the sintering temperature and bauxite content were controlled at 1300 °C and 40 wt%, respectively, the obtained membrane supports exhibited a high pure water permeance of approximately 5.36 m3·m−2·h−1·bar−1 and a high bending strength of approximately 69.6 MPa. At the same time, the optimized ceramic supports presented a typical mullite phase and excellent resistance to acid and alkali. This work provides a potential route for the preparation of ceramic membrane supports with characteristics of low cost and high performance.



2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Delffika Canra ◽  
Dedi Suwandi

The high price of a UV-photolithography aligner on the market is the reason for designing and characterize low cost UV-photolithography aligner. Photolithography process is simple but it needs patience, enable to modify photolithography aligner by using commercial components and certainly low price. The objective of this study is analyzing the ability of a commercial product in UV-photolithography process, search optimum exposure time and resolution. The method of photolithography process to be used is the method of contact alignment. Commercial UV lamps and cheap photomask are main component in this study. With a light intensity of 0.2 mW/cm2 require the exposure time at least 50 seconds. The smallest achievable resolution depends on the resolution photomask. The Results of smallest resolution is 165 m with a percentage error 10% of the original design.



Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4205
Author(s):  
Marwa H. Gouda ◽  
Noha A. Elessawy ◽  
Sami A. Al-Hussain ◽  
Arafat Toghan

The direct borohydride fuel cell (DBFC) is a low-temperature fuel cell that requires the development of affordable price and efficient proton exchange membranes for commercial purposes. In this context, super-acidic sulfated zirconia (SO4ZrO2) was embedded into a cheap and environmentally friendly binary polymer blend, developed from poly(vinyl alcohol) (PVA) and iota carrageenan (IC). The percentage of SO4ZrO2 ranged between 1 and 7.5 wt.% in the polymeric matrix. The study findings revealed that the composite membranes’ physicochemical features improved by adding increasing amounts of SO4ZrO2. In addition, there was a decrease in the permeability and swelling ratio of the borohydride membranes as the SO4ZrO2 weight% increased. Interestingly, the power density increased to 76 mW cm−2 at 150 mA cm−2, with 7.5 wt.% SO4ZrO2, which is very close to that of Nafion117 (91 mW cm−2). This apparent selectivity, combined with the low cost of the eco-friendly fabricated membranes, points out that DBFC has promising future applications.



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