Kharazmi University

About: Kharazmi University is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Membrane & Supply chain. The organization has 3395 authors who have published 5321 publications receiving 45645 citations. The organization is also known as: Tarbiat Moallem University of Tehran & Teacher Training University.

Fabrication of a new emulsion polyvinyl chloride (EPVC) nanocomposite ultrafiltration membrane modified by para-hydroxybenzoate alumoxane (PHBA) additive to improve permeability and antifouling performance

Abstract: New emulsion polyvinyl chloride (EPVC) microporous nanocomposite ultrafiltration membranes were fabricated by doping them using various amounts of para-hydroxybenzoate alumoxane (PHBA) via the phase inversion technique. High hydrophilicity of PHBA particles made it an outstanding selection for improving the membranes performance. The prepared membranes were characterized with scanning electron microscopy (SEM), energy dispersive X-ray (EDX), atomic force microscopy (AFM) techniques along with water contact angle, permeation, rejection and fouling tests. The modified EPVC membranes indicated an improvement in hydrophilicity and pure water flux because of the attendance of hydrophilic PHBA additive. All of the fabricated membranes demonstrated higher flux recovery ratio (FRR (%)) in comparison with the pristine EPVC membrane. The modified membrane with 0.5 wt.% of PHBA showed the highest water flux growth (47.1%) and the best antifouling performance (FRR = 65.3%). In addition, the rejection of the bovine serum albumin (BSA) was more than 98% for all of the prepared membranes. The performance of the neat and optimum membranes was evaluated for reusability and concentrating the whey protein and the obtained results showed that the modified nanocomposite membrane had higher fouling resistance and permeability.

Carbon dots-modified silver nanoparticles as a new colorimetric sensor for selective determination of cupric ions

Abstract: In this work, carbon dots-modified silver nanoparticles (CDs-Ag NPs) were successfully prepared by reducing AgNO 3 in the presence of carbon dots (CDs). The prepared CDs-Ag NPs were characterized by using UV–vis spectroscopy, IR spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS). Aqueous dispersions of the CDs-Ag NPs showed strong surface plasmon resonance (SPR) absorption band at 430 nm. A simple, sensitive, and selective colorimetric Cu 2+ sensor was developed on the basis of the strong interaction of functional groups of the CDs incorporated in CDs-Ag NPs with Cu +2 cations which in turn resulted in the aggregation of the nanoparticles and manifested itself in the change of color of CDs-Ag NPs dispersion from orange to red-brown. The main factors affecting the Cu 2+ detection, including pH, concentration of CDs, ionic strength, and the interaction time, were optimized for finding out the best conditions for determination of Cu 2+ . Under the optimum conditions, the analytical response (A 525 /A 430 ) was linear over the Cu 2+ concentration in the range of 0.3–8 μM ( r 2 = 0.999) and a detection limit of 0.037 μM was obtained. The method was successfully used for detection of Cu 2+ in tap and river water samples.