Showing papers in "Separation and Purification Reviews in 2011"
TL;DR: In this article, the authors proposed a strategy for effective mitigation of the long-term hazards associated with high-level waste (HLW) by actinide partitioning, where substituted malonamide extractants such as DMDBTDMA and DMDOHEMA have emerged as viable green alternatives to phosphine oxides.
Abstract: Actinide partitioning is a proposed strategy for effective mitigation of the long-term hazards associated with high-level waste (HLW). Octyl-(phenyl)–N,N-diisobutyl carbamoyl methyl phosphine oxide (CMPO) and diphenyl–N,N-diisobutyl carbamoyl methyl phosphine oxide (DφCMPO) are amongst the promising extractants extensively studied since the 1980s for actinide partitioning from wastes of different origin. During the last two decades, substituted malonamide extractants such as N,N'-dimethyl-N,N'-dibutyl tetradecyl malonamide (DMDBTDMA) and N,N'-dimethyl-N,N'-dioctyl hexylethoxy malonamide (DMDOHEMA) have emerged as viable green alternatives to phosphine oxides. During the last decade, diglycolamide-based extractants such as N,N,N′,N′-tetraoctyl diglycolamide (TODGA) and N,N,N′,N′-tetra-2-ethylhexyl diglycolamide (TEHDGA) have received considerable attention due to overwhelmingly favourable extraction and stripping efficiencies of minor actinides from different types of transuranium (TRU) wastes. The focus o...
221 citations
TL;DR: In this article, the state-of-the-art of arsenic removal by using electrocoagulation and electrodialysis was described, and the maximum arsenic removal achieved was brought down to the ppb level (10 ppb being permissible limit of World Health Organization in drinkable water).
Abstract: Electrochemical methods have been described for the removal of arsenic from contaminated water due to their advantages in comparison to other removal methods. Only electrocoagulation and electrodialysis were used for this purpose. The present review article describes state-of-art of arsenic removal by using these techniques. Attempts have been made to explain the optimization for maximum removal of arsenic by controlling metal electrodes, pH of water, current densities, processing time and ionic concentration. The maximum arsenic removal achieved was brought down to the ppb level (10 ppb being permissible limit of World Health Organization in drinkable water). Efforts have also been made to explain the mechanism of arsenic removal by these techniques. Besides, the future perspectives of electrochemical techniques for the removal of arsenic have also been highlighted.
167 citations
TL;DR: In this paper, a review on polymer precursor selection and effect of pyrolysis conditions on carbon membrane characteristics and performances were discussed in detail, and the potential applications and future directions of carbon membrane in gas separation processes were also briefly identified.
Abstract: Carbon membranes prepared by pyrolysis/carbonization of polymeric precursors have been studied in the last few years as a promising candidate for gas separation process. As the aim of this paper, a review on polymer precursor selection and effect of pyrolysis conditions on carbon membrane characteristics and performances were discussed in detail. A number of different polymer precursors have been surveyed for their utility as materials in carbon membrane fabrication. The gas transport properties of various types of carbon membrane that produced by different researchers was summarized. Furthermore, the potential applications and future directions of carbon membrane in gas separation processes were also briefly identified.
144 citations
TL;DR: Uranium solvent extraction from aqueous acidic solutions is reviewed in this paper, where various extractants used for uranium extraction and separation from acidic solutions are divided into four types: 1) nitrogen-based extractants, 2) phosphorous-based, 3) sulfur-based and 4) other extractants.
Abstract: Uranium solvent extraction (SX) from aqueous acidic solutions is reviewed. First the uranium availability in earth as well as resources, mining and production reports is presented and followed by SX basic flowsheet and various important stages. Extraction, scrubbing, stripping and finally solvent equilibrium are presented in a flow-sheet form. The second half of the review discusses the various extractants used for uranium extraction and separation from acidic solutions. The extractants are divided in four types: 1) nitrogen-based extractants, 2) phosphorous-based extractants, 3) sulfur-based extractants, and 4) other extractants. Nitrogen-based extractants cover predominantly the amides and amines functional group containing extractants. The phosphorous-based extractants: tri-butyl-phosphate (TBP), di(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl (PC88A), tri-n-octyl-phosphine oxide (TOPO or Cyanex 923) and bis(2,4,4-trimethyl pentyl) phosphinic acid (Cyanex 272) ...
116 citations
TL;DR: In this article, the authors presented the removal of some heavy metals from water solution using absorption and nanofiltration membrane techniques using the influence of temperature, sorbent mass, solution pH, flow rate and sorbent chemical modification in the adsorption process.
Abstract: The removal of some heavy metals Cu (II), Cd(II), Mn(II), Pb(II) As(III), and As(V) from water solution using absorption and nanofiltration membrane techniques is presented. The influence of temperature, sorbent mass, solution pH, flow rate and sorbent chemical modification in the adsorption process are discussed. Among the listed sorbents the best performers for higher initial heavy metal concentration are: montmorillonite, kaolin, tobermorite, magnetite, silica gel and alumina that removed more than 80% from a solution of initial concentration range 1–100 ppm for cadmium, chitosan coated magnetic nanoparticles modified with α-ketoglutaric acid removed >95% from a solution of initial concentration 200 ppm for copper, polymeric cation exchanger containing nano-Zr(HPO3-S)2 absorbs 98% of lead with initial concentration 80 ppm, acid modified carbon black has absorption efficiency of ∼80% with initial concentration 200 ppm of As(V); and polonite sorbent absorb 98.7% of manganese with initial concent...
115 citations
TL;DR: In this article, the advantages and disadvantages of electrocoagulation compared to traditional coagulation methods are reviewed and some considerations about the mathematical modeling of the process and actual reactor design are described.
Abstract: Electrocoagulation is an electrochemical technique which is being applied to the removal of a number of water pollutants: metals, organic contaminants, dyes and pigments, colloidal solids and particles, soluble inorganic pollutants, and others. Both the electrochemical reactions that take place at the electrode and the effect on the bulk solution are explained. The influence of the metal cation concentration (iron or aluminum) as well as the pH of the aqueous solution is shown. The advantages and disadvantages of electrocoagulation compared to traditional coagulation methods are reviewed. Some considerations about the mathematical modeling of the process and actual reactor design are described. Some techniques that are derived from electrocoagulation—electro-Fenton and peroxi-coagulatio—are explained. Finally, the efficiency of removal for a number of pollutants from wastewater is presented.
60 citations
TL;DR: The flaws of conventional water treatment on seawater aquaculture systems are reviewed and a new technology for membrane processes is described to remove fine particles and dissolved matter in addition to performing gas transfer.
Abstract: Removing solids is an essential task when recirculating water an aquaculture system. Dissolved solids production directly from particulate solids as well as by fish is a function of time. These contaminants can indirectly affect the fish both biologically and physically. The flaws of conventional water treatment on seawater aquaculture systems are reviewed in this paper. Then a new technology for membrane processes is described to remove fine particles and dissolved matter in addition to performing gas transfer.
32 citations
TL;DR: In this paper, the progress of researches on various polymeric particles used as adsorbents of endocrine disruptors, including porous polymeric particle, hybrid polymeric, and imprinted polymer particle, have been reviewed.
Abstract: Endocrine disruptors (EDs) have threatened our daily life severely through drinking water, cosmetics, foodstuff, and drugs. Various treatment processes for removal of EDs are studied in recent years, including membrane filtration, advanced oxidation process, biological treatment and adsorption. In this present paper, the progress of researches on various polymeric particles used as adsorbents of EDs including porous polymeric particles, hybrid polymeric particles, and imprinted polymeric particles, have been reviewed.
14 citations
TL;DR: The role of the polar properties of water in separation methods are presented in two parts: Part I: Properties of Water General principles are given of the three non-covalent energy types acting upon non-polar as well as polar entities when these are immersed in water: Lifshitz-van der Waals (LW), Lewis acid-base (AB) and Electrostatic (EL) energies as mentioned in this paper.
Abstract: The role of the polar properties of water in separation methods are presented in two parts: Part I: Properties of Water General principles are given of the three non-covalent energy types acting upon non-polar as well as polar entities when these are immersed in water: Lifshitz-van der Waals (LW), Lewis Acid-Base (AB) and Electrostatic (EL) energies. The dominant one of these three is the Lewis acid-base (AB) interaction, which in biochemical and other organic interactions are about an order of magnitude stronger than the van der Waals and electrostatic energies combined. Included are the most important equations, describing these interactions when occurring in water. Part II: Forces Originating in Water and their Significance in Separation Methods • Hydrophobic attraction between particles. • Hydrophobic interaction between solute molecules immersed in liquid water is caused by the hydrogen-bonding free energy of cohesion between the water molecules which surround these particles or solute molecules. • T...
9 citations
TL;DR: The separation and purification methods journal Separation & Purification Methods (S&P) as discussed by the authors was founded by Carel Jan van Oss, State University of New York at Buffalo.
Abstract: Professor Carel Jan van Oss, State University of New York at Buffalo, founded the journal Separation & Purification Methods in 1973, a journal published then by Marcel Dekker Inc, New York. The pub...