Preparation and characterization of PPEES/chitosan composite nanofiltration membrane

Composite membrane having chitosan (CH) as the active layer supported on Poly(1,4-phenylene ether ether sulfone) (PPEES) membrane was synthesized in the current study. The chitosan layer was crosslinked by glutaraldehyde in two different concentrations. The scanning electron microscopic images and hydraulic permeability coefficient revealed the ultrafiltration (UF) nature of the neat PPEES membrane. This was used as a new support material for the casting of chitosan layer in order to get composite membranes. The composite nature of the PPEES/CH membranes was confirmed by FESEM and DSC analysis. The Infrared spectroscopy results confirmed the crosslinking of the chitosan surface by glutaraldehyde (GA). The changes in the hydrophobic nature of the PPEES membrane surface due to deposition of chitosan active layer followed by crosslinking were studied by their contact angle measurement and water flux study. From our studies, PPEES has proved to be a good support membrane for preparation of composite membranes. Increase in GA concentration increased the salt rejection of the membrane up to 34% for NaCl and 53% for MgSO4 on one hand with a simultaneous decrease in the flux values. The hydraulic permeability coefficient values confirmed that the prepared membranes are in nanofiltration range

A review on RO membrane technology: developments and challenges

Reverse osmosis (RO) based desalination is one of the most important and widely recognized technologies for production of fresh water from saline water. Since its conception and initiation, a significant development has been witnessed in this technology w.r.t. materials, synthesis techniques, modification and modules over the last few decades. The working of a RO plant inclusive of the pretreatment and post-treatment procedures has been briefly discussed in the article. The main objective of this review is to highlight the historical milestones achieved in RO technology in terms of membrane performance, the developments seen over the last few years and the challenges perceived.The material properties of the membrane dominate the performance of a RO process. The emergence of nano-technology and biomimetic RO membranes as the futuristic tools is capable of revolutionizing the entire RO process. Hence the development of nano-structured membranes involving thin film nano-composite membranes, carbon-nanotube membranes and aquaporin-based membranes has been focussed in detail. The problems associated with a RO process such as scaling, brine disposal and boron removal are briefed and the measures adopted to address the same have been discussed. © 2014 Elsevier B.V

1-(4-Bromophenyl)-2-(2-chlorophenoxy)ethanone

In the title compound, C14H10BrClO2, a twofold halogenated derivative of phenylated phenyloxyethanone, the least-squares planes defined by the C atoms of the aromatic rings subtend an angle of 71.31 (17)°. In the crystal, C—H...O contacts connect the molecules into chains along the b-axis direction

Humic acid based biopolymeric membrane for effective removal of methylene blue and rhodamine B

Humic acid was immobilized on a polypropylene supported sodium alginate/hydroxyethyl cellulose blend membrane in the current work. The adsorption property of this membrane for the removal of cationic dyes, namely, methylene blue (MB) and rhodamine B (RhB), was extensively studied. Batch-adsorption experiments were conducted to investigate the adsorption behavior of dyes on the membrane with variation in adsorbent mass, initial dye concentration, pH, time, and temperature. The membranes were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM). Prepared membranes showed more than 98% removal capacity for both dyes under optimal conditions. Kinetic experiments revealed that the pseudo second order model exhibited the best correlation with the adsorption data. Dubinin-Radushkevich model indicated that the adsorption of dyes onto the membrane surface was by simple physisorption. The membrane was easily regenerated by simple acid treatment, and its efficiency remained significant even after four adsorption cycle