Stimuli responsive membranes in separation processes- short review

The paper discusses some basic issues related to synthesis and properties of stimuli responsive membranes. Two commonly studied forms of these  membranes  are presented, namely pore surface grafted and pore volume functionalized membranes. The critical feature allowing to classify membrane to one of the above category is their grafting yield. The first kind of membranes, known under the name of ‘membrane valves’, can be used in stimuli controlled filtration when membrane cut-off is controlled by means of external stimuli. The second  category, called sometimes ‘gating membranes’, can be used for transport facilitation of some species. The paper is illustrated by description of our attempts in syntheses of both membrane forms  and evaluation of their separation properties. 

Electro‐driven materials and processes for lithium recovery—A review

The mass production of lithium‐ion batteries and lithium‐rich e‐products that are required for electric vehicles, energy storage devices, and cloud‐connected electronics is driving an unprecedented demand for lithium resources. Current lithium production technologies, in which extraction and purification are typically achieved by hydrometallurgical routes, possess strong environmental impact but are also energy‐intensive and require extensive operational capabilities. The emergence of selective membrane materials and associated electro‐processes offers an avenue to reduce these energy and cost penalties and create more sustainable lithium production approaches. In this review, lithium recovery technologies are discussed considering the origin of the lithium, which can be primary sources such as minerals and brines or e‐waste sources generated from recycling of batteries and other e‐products. The relevance of electro‐membrane processes for selective lithium recovery is discussed as well as the potential and shortfalls of current electro-membrane methods

Modification of the surface of activated carbon electrodes for capacitive mixing energy extraction from salinity differences

This is an unedited version of this article. The publisher's edited version cab reached in this URL: http://www.sciencedirect.com/science/article/pii/S0021979714006274#The reference for this article is: Marino et al., Journal of Colloid and Interface Science 436(2014) 146-153.The “capacitive mixing” (CAPMIX) is one of the techniques aimed at the extraction of energy from the salinity difference between sea and rivers. It is based on the rise of the voltage between two electrodes, taking place when the salt concentration of the solution in which they are dipped is changed. We study the rise of the potential of activated carbon electrodes in NaCl solutions, as a function of their charging state. We evaluate the effect of the modification of the materials obtained by adsorption of charged molecules. We observe a displacement of the potential at which the potential rise vanishes, as predicted by the electric double layer theories. Moreover, we observe a saturation of the potential rise at high charging states, to a value that is nearly independent of the analyzed material. This saturation represents the most relevant element that determines the performances of the CAPMIX cell under study; we attribute it to a kinetic effect.Departamento de Física Aplicad

Micelle enhanced filtration processes : a short insight into used surfactants

The short review describes typical surfactants used for micelle enhanced ultrafiltration (MEUF). Concerning the kind of pollutant that has to be removed from aqueous solutions, different surface-active species can be applied. However, to get the efficient separation two bodies have to be selected: a specific surfactant and an ultrafiltration membrane. Each procedure has its own rules to be fulfilled

ELECTROMEMBRANE PROCESSES FOR DESALINATION Preface

WOS: 00033701830000

Hybrid capacitive deionization with anion-exchange membranes for lithium extraction

Lithium is considered to be a critical material for various industrial fields. We present our studies on extraction lithium from diluted aqueous solution by novel hybrid system based on a membrane capacitive deionization and batteries desalination. Hybrid CDI is comprised by a lithium selective adsorbent, activated carbon electrode and anion-exchange membranes. Here, we demonstrated implication of various type of anion-exchange membranes and influence their properties on effective capacity and energy requirements in charge/discharge steps. We described a configuration with anion-exchange membrane characterized by adsorption capacity of 35 mg/g of Li+ with 0.08Wh/g and removal efficiency of 60 % of lithium ions, using novel selective desalination technique

Modified Poly(vinylidene fluoride) by Diethylenetriamine as a Supported Anion Exchange Membrane for Lithium Salt Concentration by Hybrid Capacitive Deionization

This paper shows the investigation for the optimal anion exchange membranes (AEM) supporting the desorption step of the HCDI process. The chemical modification of PVDF by diethylene triamine created the AEM. To confirm the ion-exchange character of materials, the chemical analysis with FTIR, SEM, surface energetics, and transportation analysis were applied. Next, the investigated membranes were applied for the sorption and desorption of lithium chloride. The specific sorptive parameters were higher according to the incorporation of the nitrogen groups into polymeric chains. Considering the desorption efficiency, membranes modified by four days were selected for further evaluation. The application in the HCDI process allowed reaching the desorption efficiency at 90%. The system composed of PVDF-DETA4 membrane was suitable for sorption 30 mg/g of salt. By applying the PVDF-DETA4 membrane, it is possible to concentrate LiCl with four factors. The anion exchange character of the developed membrane was confirmed by adsorption kinetics and isotherms of chlorides, nitrates, sodium, and lithium. The prepared membrane could be considered a perspective material suitable for concentration salt with electro-driven technologies for the above reasons