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Questions related from Foroogh Khodadadi
Dear researchers, I want to determine the magnetic properties of my samples. I did the VSM test and attached the results. Could you please help me interpret the VSM graphs? Thank you so much....
07 February 2025 4,996 4 View
Dear Researcher, There is a porous film acting as a barrier between a high-pressure section (right side) and a low-pressure (vacuum, left side) section. Molecules can pass through the porous film,...
07 February 2025 8,979 0 View
I dissolved 0.4 g of DCC and 0.06 g of DMAP in 5 cc of DMF. After a few minutes, a white precipitate formed at the bottom of the container. Could you provide information on the solubility limits...
30 January 2025 9,354 1 View
I am working on making graphene oxide (GO) hydrophobic by attaching hydrophobic chains to its functional groups using a Steglich esterification reaction. I experimented with various ratios of...
30 January 2025 2,269 1 View
If we have 0.012 g GO-OH, then how can we determine the amount of other materials like Y-COOH, DCC, and DMAP, in 15 cc DMF solvent in a Steglich reaction when we do not know the molecular weight...
30 January 2025 8,005 2 View
Dear researchers, I have magnetite (Fe3O4) on a solid surface. How can I understand the amount of it only on the surface of a solid surface, not in its balk and texture? Thank you so much
07 October 2024 3,122 6 View
Dear researchers, I have come across the terms "Thermal Welding" and "Friction Welding" in various literature when referring to attaching a polymeric membrane sheet to a polypropylene frame....
23 September 2024 2,709 0 View
Dear researchers, In a multi-effect vacuum membrane distillation package, does the vacuum pump operate continuously, or does it run intermittently (run and stop repeatedly)? Thank you so much...
23 September 2024 8,505 0 View
Dear Researchers, I have some questions regarding multi-effect vacuum membrane distillation and would greatly appreciate your insights: 1. Why is a thermal storage tank used instead of directly...
23 September 2024 4,086 0 View
Dear Researchers, In a multi-effect vacuum membrane distillation package, How is a vacuum pump used to evacuate the permeate side of the membranes without any vapor damage? Thank you so much....
23 September 2024 3,375 0 View
Dear researcher, In a multi-effect vacuum membrane distillation process: Why is a thermal storage tank used instead of directly heating the salty feed? Thank you so much. Regards
23 September 2024 6,486 1 View
Dear researchers, In a MEMSYS multi-effect vacuum membrane distillation package, how do the hot feed and vapor transfer between the channels created by the frame spacing? Best regards
23 September 2024 8,665 0 View
Dear researchers How to prepare buffer solution with pH of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 using NaH2PO4 and Na2HPO4? Should we use NaOH and HCl?
03 May 2024 3,363 1 View
Dear researchers, We analyze data by RSM in experimental design software. But, how to draw a Pareto Chart based on response surface methodology (RSM) information?
21 April 2024 9,499 3 View
Hello esteemed researchers, I'm encountering an issue with exporting graphs from Design Expert software into a Word document; the graph explanations are included alongside the images. Could...
03 April 2024 6,475 0 View
Dear researchers, Why do scientists use temperatures between 60 to 70 C to dissolve PVDF in DMF or DMAc for membrane fabrication? Why do not we use a temperature of 90 C to dissolve it in a...
09 October 2023 6,565 0 View
Dear researchers, Is it possible to use ice in the second wall of the condenser? What is your idea?
25 September 2023 7,552 0 View
There are a lot of different types of vacuum pump models like oil-sealed pumps and dry pumps, Vacuum water pumps, positive displacement pumps, momentum transfer pumps, entrapment pumps, and...
04 September 2023 6,805 1 View
Can I use a refrigerator compressor instead of a vacuum pump in a membrane distillation setup?
04 September 2023 2,229 1 View
I wanna design some experiments with these conditions: 1. Parameter A: It is 40, 50, 60, 70. 2. Parameter B: It is 3, 10, 50, 200.
03 September 2023 5,633 0 View
Dear researchers, I bought some membrane production materials like PVDF, DMF, DMAc, PEG200, PVP, SiO2, etc. How can I prove that these materials are pure and not from industrial grades or...
01 September 2023 6,023 3 View
Dear Researchers, I want to use Design-Expert software version 7.0.0 to design the experiments for 3 parameters. How can I design a series of experiments using Expert-Design software for 3...
29 August 2023 8,618 5 View
In the membrane distillation process, a spacer/mesh is used to prevent the membrane from sticking to the surface of the module. On which side of the membrane should this spacer be placed? on the...
22 August 2023 9,343 1 View
An oil pressure gauge is used in a water treatment setup and shows no change after flowing water in the pipes! Did any researcher face this problem? Best regards
22 August 2023 3,323 4 View
The membrane distillation modules I work with have large dimensions and large membranes must be made. But in some membranes, a few tiny holes are created in different parts of the membrane,...
22 August 2023 790 2 View
In pressured-based membrane technologies, such as MF, UF, and NF, we use the following equation to determine the membrane flux: J= L/(A.t.p) with the unite of LMHbar Do we consider vacuum pressure...
22 August 2023 7,602 0 View
Dear researchers, I have a Polytetrafluoroethylene (PTFE) powder that the powders stuck together and created large particles (agglomeration). I have been able to reduce the size of the polymer...
24 December 2022 6,026 3 View
Dear researchers, Merck Co. introduced a withdrawal system with manual pressure build-up for solvents in bottles (See the attached photo). Using this equipment to remove solvents is safe, easy...
22 December 2022 8,583 4 View
Dear researchers, We know that spiral wound, hollow fiber, and plate and frame configurations are three membrane module types. However, no particular text is about the fabrication of plate and...
21 October 2022 3,396 0 View
Dear researchers, Considering the dimensions of the Plexiglass DCMD cell, I want to fabricate a VMD cell only by removing the cold water inlet. Then we have one inlet (hot water) and two...
11 October 2022 2,246 0 View
Dear researchers, I am preparing a VMD setup on a lab scale. As you know, VMD needs a vacuum pump. However, there are many types of the vacuum pumps such as: rotary vane vacuum pumps. diaphragm...
11 October 2022 436 1 View
Dear researchers, Looking at the materials, it can be found that the researchers used the same materials for the modification of polymeric membranes for both ultrafiltration (UF) and membrane...
09 October 2022 5,334 1 View
Dear researchers, It seems that in the vacuum membrane distillation process, the vacuum pump is connected to the permeate tank. If it is true, the vapore/water can enter to the vacuum pump and...
07 October 2022 7,087 0 View
Dear researcher, I am preparing a VMD set up. Can I use a refrigerator motor instead of a condenser to reduce the cost of the set up preparation? Regards
07 October 2022 1,121 0 View
Dear researchers, It is well known that there are different types of nonwoven polyester fabrics. But which of them is better for the flat sheet hydrophobic PVDF membrane preparation for the MD...
12 September 2022 4,829 0 View
Dear researchers, I have a plan for the dimensions of a lab-scale DCMD membrane distillation cell. Can I fabricate a DCMD membrane distillation cell and use it in Vacuum Membrane...
12 September 2022 8,783 4 View
Dear researcher, Grafting is a common method for modifying the polymeric membrane surface to be more anti-fouling. But, can we use this method for surface modification in pilot and industrial...
05 September 2022 5,015 1 View
Dear researchers, How can we add Hydrogen sulfide gas to an acid solution at 50 C? Regards
01 September 2022 5,243 0 View
Dear researchers, How can we warm a very high TDS water on the lab and pilot scale? Thank you so much Regardson
28 August 2022 6,068 1 View
Dear researchers, How to fabricate a pilot-scale flat sheet superhydrophobic PVDF membrane using commercially available materials? Thank you so much. Best regards
28 August 2022 1,976 0 View
Dear researchers, I do not know how to use Origin software to draw a graph with very high (3000) and very low (100) numbers on the vertical axis. Could you please help me?
06 August 2021 6,953 1 View
Hi, I have an ultrasonic bath without degas mode. How can I adjust the frequency to have the degas mode for polymeric solutions. Thanks
19 June 2021 5,610 0 View
Dear researchers, It is clear that BSA protein is the most common solute for membrane performance examination. However, there is no reference to check the MWCO of the membranes based on BSA...
30 April 2020 6,319 3 View
Dear researchers, The mentioned solvents are organic solvents and it is thought that they can dissolve the oils. If they are not capable to do this, what is the reason? Regards DMAc:...
26 February 2020 383 2 View
Dear researchers, We all know that dextran is used to control the crystallization process of sugar. But can dextran make crystals in high concentrations? Regards
07 January 2020 1,184 5 View
Dear researcher, We all use the non-solvent additives to improve the structure and performance of the polymeric membranes. However, the non-solvent additives can be easily washed out quickly with...
30 December 2019 5,549 1 View
Dear researchers, I want to put my SEM photos together to have a picture like the attached photos for my article. Could you please guide me what is the software that I can use? Regards
17 December 2019 4,366 12 View
Dear researchers, I want to determine the estrogen hormone concentration in water. Where is the special laboratory to do this in Iran? Could you please guide me? Best regards
12 December 2019 3,029 2 View
Dear researchers, There are different ways to prepare the data for the ternary phase diagram of the phase inversion process during the solidification of a membrane solution. We all agree...
05 December 2019 8,192 4 View
Dear researchers, There are some white bubbles on the surface of the SEM micrographs. What are these particles? Kind regards Foroogh
26 November 2019 5,553 3 View
Dear researchers, What are the detection methods for Estrogen hormone in the aqueous solution? Can we use the UV-visible spectroscopy for Estrogen hormone (E1, E2 or EE2) detection? What is the...
06 November 2019 2,945 4 View
It is reported that PES/DMSO membranes are too brittle. Is there any method or additive to make them more flexible? Regards
19 October 2019 1,822 6 View
Dear researchers, Power law model is one of the simplest models for non-Newton fluids. There are two constants i.e. " n and k" in this model. the more the n is lower than 1, the more the fluid...
05 August 2019 6,817 3 View
Dear researchers, The surfactants are extracted from the nature are more useful. Can any one introduce an available cheap (herbal) surfactant to produce water/oil emulsion? Thank you so much....
09 March 2019 4,736 7 View
Based on the related formulation, in the fixed casting thickness for example (200 micron), shear rate is increasing by casting speed. It means the higher the casting speed, the higher the shear...
15 January 2019 1,631 3 View
Dear Researchers, I need a 3D photo of a porous material such as attached one only to show the porosity, not for analyzing porous materials. Can any one help me? Regards Foroogh
20 October 2018 7,606 6 View
Hi, How can I produce 3D photos like the attached one? That is not for analysis. This is only for showing porous materials. Regards
20 October 2018 9,762 3 View
Dear researchers, I fabricate the UF PVDF membranes by phase inversion method (NIPS); therefore, they are water- wet membranes. Then I immerse them in aqueous alcohol solution. What is the reason...
04 October 2018 6,799 2 View
I am a membrane researcher and sometimes expose with some formulations that the prepared membranes with same formulation and casting condition do not have same properties, specially about the pure...
12 March 2018 8,535 3 View
There are some abnormal particles, which have smallpox form, on the SEM cross section images of NF PES membranes. What are these?
10 March 2018 9,994 4 View
I made an UF membrane with 22 wt% of PVDF polymer and 5 wt% PEG200 in the casting solution. The dope solution was viscose. Some irregular lines are observed on the surface SEM micrograph. Are they...
08 March 2018 3,968 3 View
Overall porosity is a sign of voids and holes in the membrane matrix. How does it affect on membrane rejection percent?
06 March 2018 6,909 2 View
We all know that dead-end cell has vertical pressure and cross flow has horizontal pressure on the membrane surface. What is the correlation between these two pressures? I tested my membranes with...
06 March 2018 5,597 7 View
I think BSA molecules are hydrophobic and are attracted by polymeric hydrophobic surface by van der waals forces and it causes concentration polarization which makes flux decline. But can we say...
05 March 2018 3,715 2 View
We all know how can we measure the water content or water uptake and porosity of the polymeric membranes. In my view they are both, related to void fraction of the membranes and water contact...
05 March 2018 5,086 5 View
We all know, every alcohol has its own surface tension that affects on capillary forces. But what is better material for porosity determination and why?
05 March 2018 3,948 4 View
Hi to all. I want to know what happen in phase inversion in the coagulation bath deeply. For sure the Gibbs free energy, Entropy and Enthalpy have important roles in this process.
03 February 2018 4,114 4 View
I saw the PEGs (for ex PEG200) in surfactant classification list, but these materials can not form a micelle. What is the reason?
24 December 2017 538 3 View
Its common to use the protein or Dextran (3 to 2000 KDa) solutions for detecting the MWCO of UF membranes. But, What is the cheapest solution for characterizing the UF polymeric membranes with...
22 December 2017 2,579 4 View
For characterization of a membrane, we have to test different sections and then consider the average of the results. Why do they have different properties !?
21 December 2017 679 2 View
The rejection test of UF membranes commonly does by BSA and dextran solutions. These materials have different structures and so maybe different behaviors in concentration polarization phenomena....
21 December 2017 3,401 0 View
After the casting step, the UF membrane film is immersed in the coagulation. The pure water flux of the wet PVDF membrane is determined after 1 and 5 days. These flux numbers are different....
27 November 2017 6,886 2 View
The dynamics of wet phase inversion were characterized by the solvent-nonsolvent exchange rate, which could give information concerning the development of morphology and the structure of the...
12 November 2017 7,926 0 View
One of the important factor on the membrane performance is heat treatment or thermal annealing. What is the effects of thermal annealing during membrane fabrication process on the membrane...
11 November 2017 3,528 2 View
UF membranes use for RO pretreatment. If MWCO of UF membrane is low for sure the UF membrane fouling would be sever. And if the MWCO is high the solutes would pass and then we have sever fouling...
16 October 2017 908 6 View
I fabricate polymer solutions with a high viscosity and degass them under vacuum. But when I want to pump these solutions, air bubbles produce again. What is the suitable pump for moving solutions...
08 October 2017 5,941 6 View
A polymeric solution consist of base polymer + solvent+ additives. During phase inversion process in the coagulation bath additives leach out. Is it necessary to leach out all of them from the...
26 September 2017 9,268 1 View
How do we determine the concentration of organic materials like DMAc or PEG in a dilute aqueous solution? do you know any sensor ?
24 September 2017 3,957 3 View
After casting step, the nascent membrane is immersed in coagulation bath (pure water, 20 C). The second bath is related to washing the membrane and removing exist solvent. What is the best...
10 September 2017 4,272 0 View
We have Three materials here : PEG + LiCl + DMAc Could you help me to know what the intermolecular force and sterostructure are between them? PEG + LiCl PEG+ DMAc
08 September 2017 5,368 3 View
The PVDF thin film cast on non-woven polyester support to fabricate a membrane. How is created physical bond between PVDF chains and polyester fibers?
06 September 2017 8,607 5 View
How these materials interact with each other ?
05 September 2017 7,641 3 View
Different speeds are used for casting process and this parameter is associated with viscosity of dope solution and shear stress. But what is the effect of casting speed on toplayer and sublayer of...
04 August 2017 4,580 1 View
Some papers reported the value of the Hansen Solubility Parameters of Different molecular weights of polyethylene glycol like PEG200,400,600,6000 that are different with toghether. Reference of...
04 October 2016 553 1 View
Dextran have been used for determination the MWCO of UF membranes. Separation results of TOC tests for Dextran 150 KDa is like Dextran 70 KDa. And some sources suggested that if ultrafiltration...
02 October 2016 5,879 4 View
The result of ultrafiltration test for bovine serum albumin (BSA), with MW=67000, indicates by the high rejection rate of 99%, while the TOC’s result for Dexteran (MW=150000) unexpectedly...
07 June 2016 6,485 5 View
Dear researchers, There are a lot of different materials and methods that we can use to make a superhydrophobic flat sheet PVDF membrane. However, there are some problems to bring them into the...
01 January 1970 1,338 0 View
