Suchergebnisse

Department of Chemistry, Sukhadia University, Udaipur-313 001 Department of Mines and Geology, Government of Rajasthan, Udaipur Manuscript received 28 April 1993, revised 29 December 1995, accepted 1 April 1996 Ion Exchange Column Studies with Aniline.

ABSTRACTThe ion‐exchange nitrate‐removal plant installed at Isleham, Cambridgeshire was commissioned during 1990. A description of the plant and design considerations is given, together with operational data. The nitrate‐removal plant treats up to 4.5 Ml/d of chalk borehole water. Problems encountered are presented together with information on capital and operating costs.

By the method of potentiometric titration of a fibrous aminocarboxylic polyampholyte with a predominant content of carboxyl groups, the equilibrium of the cation exchange of calcium, magnesium, and potassium ions for a hydrogen ion was studied. Due to the low solubility of calcium and magnesium hydroxides in these cases, titration was carried out by Ca(OH)2 and Mg(OH)2, which are formed in solution upon contact with the H-form of the ion exchanger оf increasing portions of solid CaO and MgO. This made it possible to obtain titration curves in a wide range of pH and calcium and magnesium chlorides concentration (0–0.1 eq./L). The dependences of the swelling of ion exchangers on the neutralization degree with the bases of the studied cations are obtained. The coefficients of ion-exchange equilibria are calculated. It was found that the swelling of the ion exchanger is relatively little dependent on its ionic form. The ion exchanger has a higher affinity for calcium than magnesium ion.

The sorption properties of new iminodiacetate fibrous cation exchanger FIBAN XC-1 synthesized on a chemically resistant matrix of polypropylene fiber with a grafted copolymer of styrene and divinylbenzene, which can withstand elevated temperatures and aggressive environments, were studied. It was shown that the fibrous chelate ion exchanger FIBAN XC-1 is an effective sorbent of heavy and non-ferrous metals from multi-ionic aqueous solutions under static and dynamic conditions. It was found that the cation exchanger operates at high speeds up to 20 column volumes / min in water purification from copper and lead ions (purification from Cu2+ – 82 % and purification from Pb2+– 65 %). It was found that the fibrous chelate ion exchanger FIBAN XC-1 is easily regenerated and does not lose its sorption and mechanical properties in the sorption– regeneration cycles.

This work has received funding from the European Institute of Innovation and Technology (EIT), a body of the European Union, under the Horizon 2020, the EU Framework Programme for Research and Innovation. Project Name and Number: 680652 Credit -18243. SUEZ water technologies and solutions is acknowledged for the supply of the membranes ; Electrodiffusion of ions in both cation (CEM) and anion exchange membranes (AEM) has been studied with theoretical calculations and experimental studies. Calculations are based on the Finite Element Method (FEM) using COMSOL Multiphysics® software. Nernst-Planck equations are solved in multi-ionic systems where no closed form solutions are available. Simulations are compared with laboratory-scale experiments in terms of current efficiency and membrane selectivity. Simulations revealed unexpected features in transport, due to coupling of ionic fluxes when the local electroneutrality condition is assumed. Transport of weak electrolytes showed the importance of involving ionic equilibria along the concentration profiles in both solutions and membranes, compelling to consider ionic constituents. The advantage of the COMSOL simulations is the ease to find concentration and potential profiles across the entire system, and to split fluxes to diffusion and migration contributions, showing their coupling even in the absence of electric current. ; Peer reviewed

"Contract no. AT(07-2)-1."--P. [2] of cover. ; "E. I. du Pont de Nemours & Co., (Inc.), Explosives Department-Atomic Energy Division, Wilmington, Delaware."--P. [1] of cover. ; "March 1952."--P. [1] of cover. ; "DP-4."--P. [1] of cover. ; "U.S. Government Printing Office: 1955."--P. 38. ; Cover title. ; Mode of access: Internet.