Temperature Enhancement of Zinc and Iron Separation from Chromium(III) Passivation Baths by Emulsion Pertraction Technology

Liquid membranes for separation of metal ions from wastewaters

The paper reviews application of various liquid membranes (LM), particularly of emulsion and supported liquid membranes, for metal separation from model and industrial wastewaters. A variety of carriers and separation systems is shown. Not only model solutions on a laboratory scale are presented but also some examples of real wastewater separation with LM are reported.

Electroplating wastes

Electroplating and other metal finishing industries, like every metal and metallurgical industry, are associated with the generation of waste. Spent electroplating baths, waste pickle liquors, etching solutions and rinse waters from electroplating units and steel finishing operations are complex solutions containing acids and several hazardous metals. It is compulsory, for environmental and economic reasons, to treat these solutions for recovering acid, metals and/or reusing these solutions/waters. This article is a review on the characterization of the wastes that are generated in electroplating industry, steel processing and copper etching in printed circuit boards manufacture, as well as on the treatment and regeneration methods of such streams. Various techniques, such as neutralization, crystallization, evaporation, pyrohydrolysis, electrodialysis, ion exchange, classical solvent extraction and membrane-based solvent extraction are presented, their advantages and disadvantages being scrutinized.

Yttrium (III) Recovery with D2EHPA in Pseudo-Emulsion Hollow Fiber Strip Dispersion System

Yttrium (Y) is an essential lanthanide rare earth element and can be effectively extracted and purified using a hollow fiber supported liquid membrane (HFSLM) system. However, the stability of HFSLM system is a significant challenge. Pseudoemulsion-hollow fiber strip dispersion (PEHFSD) system, providing excellent stability, is attracting research attention. In this work, the recovery of Y(III) by PEHFSD system using di(2-ethylhexyl)phosphoric acid (D2EHPA) as a carrier was investigated. The effects of several operating parameters, including the initial concentration of Y(III) in the feed phase, the flow rate of feed, the stirring speed and the volumetric ratio of feed to strip on Y(III) separation were studied. The Y(III) transport was analyzed on the concentration ratio of Y(III) ions, percent extraction, percent stripping and overall mass transfer coefficient (K_p). The PEHFSD system outperformed HFSLM system regarding separation performance and stability. K_p of HFSLM system decreased after the second run, but K_p of PEHFSD system remained constant even at the fifth run. The dispersed droplets in the strip dispersion phase in the PEHFSD system enhanced separation performance and stability of the membrane module.