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Questions related from Foroogh Khodadadi
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...
12 December 2019 5,825 1 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 5,819 2 View
Dear researchers, I want to produce PES solutions using DMSO as the solvent. I have some tiny white particles in my polymeric solutions even after 48 h mixing using magnetic stirrer at 50 C. I...
10 October 2019 7,846 6 View
Hi researchers, Based on the SEM images of the membrane cross section, at the sub-layer of a porous membrane, there are many long macro-voids. Can these macro-voids be considered as...
10 October 2019 7,704 2 View
Dear researchers, Ethyl lactate is a green solvent which can be replaced by toxic solvents such as DMAc, DMF, NMP, etc. But there are only a few reports for CA/Ethyl lactate. It seems this solvent...
08 August 2019 4,334 11 View
Hi researchers, The RO modules are designed in "horizontal packs" in water treatment companies. What is the reason? Could you please give me a reference? Regards Foroogh
01 January 2019 5,094 9 View
We all know that during solid drying, free water and bound water has two different mechanisms. How can we estimate the bound water concentration in a porous solid?
09 September 2018 9,846 2 View
Dear researchers, I am preparing polymer solutions with this composition: Polymer= PVDF - 18 wt% Additive= PEG200- 5 wt% Solvent= DMAc- 77 wt% Firstly DMAc+ PEG mix at 100 rpm and 25 C and then...
09 September 2018 9,582 7 View
Dear researchers, I used 3 different impellers to prepare the same polymer solution (fixed composition) which their pictures were attached. Why the prepared polymer solutions have different...
09 September 2018 7,782 22 View
Dear researchers, I am producing polymer solutions in both Lab and Pilot scales for membrane manufacturing. What are important differences between Lab-scale (glass bottle-50gr) and Pilot-scale...
09 September 2018 5,152 12 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...
03 March 2018 908 3 View
Overall porosity is a sign of voids and holes in the membrane matrix. How does it affect on membrane rejection percent?
03 March 2018 9,919 3 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...
03 March 2018 6,051 7 View
We all know that solvent (in the membrane film)/water (in the bath) replace in the coagulation bath because of the high miscibility between them. Can any researcher explain this phenomena deeper,...
02 February 2018 7,155 2 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 !?
12 December 2017 2,470 3 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....
12 December 2017 9,221 0 View
I saw the PEGs (for ex PEG200) in surfactant classification list, but these materials can not form a micelle. What is the reason?
12 December 2017 7,577 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...
12 December 2017 4,090 3 View
I would like to remove dissolved and entrapped air bubbles from a viscous polymer solution to avoid cracks on the flat sheet membrane surface. I've already tried to remove them by vacuuming but it...
11 November 2017 1,122 8 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 7,652 2 View
Every researcher check the UF membrane MWCO with different materials like BSA, Dextran, PEG and ... in different operation conditions. What is the standard protocol for MWCO determination?
11 November 2017 8,959 5 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...
10 October 2017 8,513 5 View
How these materials interact with each other ?
09 September 2017 4,072 4 View
These two surfactants, PEG and Tween80, dissolved in DMAc (organic solvent). I wanna know what is the sterostructure of molecules and the intermolecular face between them.
09 September 2017 6,576 4 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
09 September 2017 2,015 3 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...
09 September 2017 8,401 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 ?
09 September 2017 2,490 3 View
During the phase inversion process the solvent leaches out of the membrane film. What is the best place for getting aqueous solution samples to determine the solvent concentration? Is it the...
09 September 2017 6,791 2 View
Dope solutions containing different percents of the same kinds of materials have different colors. what is the reason ?
08 August 2017 5,252 0 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...
10 October 2016 3,964 1 View
We have been used of Teijin polyester support to prepare PVDF ultrafiltration membranes. How can break these membranes for cross section SEM analysis. This can not be done using liquid nitrogen.
10 October 2016 8,337 7 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...
10 October 2016 7,830 4 View
Other researchers investigated the difference between supported and nonsupported membranes. They reported that nonsupported membranes are free and shrink during immersion but supported membranes...
10 October 2016 8,167 3 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...
06 June 2016 9,321 6 View
