Advances in seawater desalination technologies

Molecular separation with organic solvent nanofiltration: a critical review.

The methods and mechanisms of nonsolvent induced phase separation have been studied for more than fifty years. Today, phase inversion membranes are widely used in numerous chemical industries, biotechnology, and environmental separation processes. The body of knowledge has grown exponentially in the past fifty years, which suggests the need for a critical review of the literature. Here we present a review of nonsolvent induced phase separation membrane preparation and characterization for many commonly used membrane polymers. The key factors in membrane preparation discussed include the solvent type, polymer type and concentration, nonsolvent system type and composition, additives to the polymer solution, and film casting conditions. A brief introduction to membrane characterization is also given, which includes membrane porosity and pore size distribution characterization, membrane physical and chemical properties characterization, and thermodynamic and kinetic evaluation of the phase inversion process. ...

Preparation and Characterization of Membranes Formed by Nonsolvent Induced Phase Separation: A Review

Modification of polyethersulfone membranes – A review of methods

More than 1000× uranium exists in the oceans than exists in terrestrial ores. With nuclear power generation expected to increase over the coming decades, access to this unconventional reserve is a matter of energy security. With origins in the mid-1950s, materials have been developed for the selective recovery of seawater uranium for more than six decades, with a renewed interest in particular since 2010. This review comprehensively surveys materials developed from 2000–2016 for recovery of seawater uranium, in particular including recent developments in inorganic materials; polymer adsorbents and related research pertaining to amidoxime; and nanostructured materials such as metal–organic frameworks, porous-organic polymers, and mesoporous carbons. Challenges of performing reliable and reproducible uranium adsorption studies are also discussed, as well as the standardization of parameters necessary to ensure valid comparisons between different adsorbents.

Materials for the Recovery of Uranium from Seawater

Preparation, Characterization and performance of polyethersulfone ultrafiltration membranes

Casting and characterization of cellulose acetate butyrate based UF membranes

Crosslinked polyacrylamides were synthesized by solution polymerization using benzoyl peroxide as the radical initiator. The water–insoluble polymer obtained was functionalized by reacting with hydroxylamine to convert the amide group into hydroxamic acid group. The resultant functionalized polymer was characterized in terms of moisture uptake, elemental composition, IR spectra, thermal stability, exchange capacity and heavy metal sorption. The sorbent, obtained in particulate form, was investigated for its sorption properties with respect to uranium from uranyl nitrate solutions under unstirred batch conditions. This paper will concentrate on preparation, characterization and performance evaluation with respect to uranium sorption as a function of concentration, time, solution pH and temperature. The potential of this sorbent for uranium and other heavy metal ion recovery from sea water is ascertained.

Polyhydroxamic Acid Sorbents for Uranium Recovery

Synthesis and characterization of low molecular weight cut off ultrafiltration membranes from cellulose propionate polymer

Composite polyamide membranes are prepared using in-situ interfacial polymerization using mixed amine system comprising 1,4-phenylene diamine and pipperazine. Separation performance of the membranes are studied as a function of the concentration of amine and acid chloride, the concentration ratio of the amines, nature of the acid chloride, and the presence of surfactant and acid acceptor in the aqueous reagent. The effect of esterification and hydrazide reactions involving residual carboxylic acid groups in the polymeric membranes on the co-polymeric composite membrane performance is also studied. The membrane performance can be tailored easily by conversion of the residual reactive functional groups in post-treatment.

V. Ramachandhran

Papers

Preparation, Characterization and performance of polyethersulfone ultrafiltration membranes

Casting and characterization of cellulose acetate butyrate based UF membranes

Polyhydroxamic Acid Sorbents for Uranium Recovery

Synthesis and characterization of low molecular weight cut off ultrafiltration membranes from cellulose propionate polymer

Separation Behavior of Composite Polyamide Membranes from Mixed Amines: Effects of Interfacial Reaction Condition and Chemical Post-Treatment