Low energy positron annihilation study of composite reverse osmosis membranes

Vacancy profile in reverse osmosis membranes studied by positron annihilation lifetime measurements and molecular dynamics simulations

The positron annihilation technique using a slow positron beam can be used for the study of the vacancy profiles in typical reverse osmosis (RO) membranes. In this study, the vacancy profile in the polyamide membrane that exhibits a high permselectivity between ions and water was studied using the positron annihilation technique and molecular dynamics simulations. Orthopositronium (o-Ps) lifeti...

Performance and Structure of Thin Film Composite Reverse Osmosis Membranes Prepared by Interfacial Polymerization in the Presence of Acid Acceptor

During interfacial polymerization (IP) reaction between m-phenylenediamine (MPDA) and trimesoyl chloride (TMC), a by-product, i.e. hydrochloric acid can produce. This produced acid diffuses back in aqueous phase and protonates MPDA and reduces its reactivity that results in lowering of polymer yield and performance of membrane. Further, for getting consistency in reverse...

Qcd Physics Opportunities in Low-energy Electron-positron Annihilation∗

I survey a number of interesting tests of quantum chromodynamics at the amplitude level which can be carried out in electron-positron annihilation and in photon-photon collisions at low energy. Some of the tests require e+e− center of mass energy as small as √ s = 2 GeV. Other tests which involve a spectrum of energies can be carried out advantageously at high energy facilities using the radiat...

Reverse Osmosis Field Study

Composite Polyamide Reverse Osmosis (RO) Membranes – Recent Developments and Future Directions

Thin Film Composite – Polyamide (TFC-PA) are commonly used reverse osmosis (RO) membranes in water desalination and waste water applications. Their poor chlorine tolerance and fouling characteristics constrain the life and performance leading to stringent chemical pretreatment requirements. In this context, development of fouling resistant and chlorine tolerant RO membranes would be relevant to...