Characterization of membranes with X-ray ultramicroscopy

Abstract

Non-invasive characterization and observation of synthetic membranes is an important practice to monitor the performance of membrane process. Primarily there are two techniques -optical and non-optical for this purpose. Among them, X-ray computed tomography, as a non-optical technique, has been extensively used for the measurement of fibre distribution and air pockets trapped in the modules. However, the micro resolution of most commercial systems has limited its application which can hardly be used for the sub-micro characterization of membrane processes. A novel micro and nano characterization method is introduced in the current work by exploring an innovative development of the X-ray ultramicroscope (XuM) and micro-tomographic techniques. The XuM, based on using a scanning electron microscope as host, provides a new approach to X-ray projection microscopy. It has demonstrated the ability to characterize very small features in objects, down to of order 100 nm, including the use for dry, wet and even liquid samples. It can also distinguish objects with very subtle difference in density.

Mechanical properties of water desalination and wastewater treatment membranes

“…In addition, 3D imaging based approaches such as X-ray tomography using both synchrotron and laboratory sources is also potential techniques for studying pore shape evolution, pore orientation, pore size distribution, and neighboring pore interaction during the deformation of the porous membranes [191] and [192]. This technique has been used for imaging and reconstructing the porous structure of water treatment membranes without deformation [193], [194] and [195]. Recently, Viguié et al [196] used this technique with a resolution of one micron to reconstruct the 3D structure of their hollow fiber membranes.…”

Experimental methods in chemical engineering: Scanning electron microscopy andX‐ray ultra‐microscopy—SEMandXuM

“…The red blood cells were infected with malaria, and in some cases, the parasite could be identified within the cell. [ 55 ]…”

“…and 100 μm thick) mounted on a Ta film 0.5 μm thick. [ 55 ] The Ta film was arranged at 45° to the incident electron, beam and the resulting X‐rays passed through the sample cell and onto the detector. A suspension of polystyrene particles in distilled water was held within the PTFE tube.…”

“…The red blood cells were infected with malaria, and in some cases, the parasite could be identified within the cell. [55] As a further example of the application of the XuM technique, the second type of ISC, composed of a PTFE tube (200 μm I.D. and 100 μm thick) mounted on a Ta film 0.5 μm thick.…”

Interlaboratory studies of highly permeable thin‐film composite polyamide nanofiltration membrane

“…Several studies have been investigated regarding the use of new polymeric precursors including mixed acid chlorides like 5-isocynate-isophthaloyl chloride or trimesoyl chloride (TMC) with phthaloyl chloride [8][9][10] or mixed amines like m-phenylenediamine (m-PDA) or piperazine with 3,5-diaminobenzoic acid [5,[10][11][12][13][14] for thin-film formation. On the other hand, chemical modification and functionalization of the formed thin layer over the ultrafiltration support membrane have also been accomplished by introduction of sulfonic acid [15][16][17] or carboxylic acid groups, [11] or incorporation of various polymers, such as poly(vinyl alcohol) and poly(vinyl phenol) to the aromatic polyamides [18,19] to improve water permeability. The mentioned methods for the modification of thin film on reverse osmosis and NF membrane result in the enhancement of permeation flux without compromising rejection.…”