Removal of Trace Metals by Foam Separation Processes

Abstract

This article describes research on the use of foam separation processes for removing metal ions from water. Whether the removal process is a foam fractionation, precipitate flotation, or ion flotation depends primarily on the nature of the metal‐collector product, the sublate. Factors affecting the solubility of the sublate, and therefore the mechanism, include the coordination behavior of the metal toward the collector surfactant, the nature of the collector, and the pH of the solution. Other variables that may significantly affect the removal process include the rate of gas flow, the concentrations of metal and collector, and the ionic strength of the solution.

Removal of Cadmium(II) from Aqueous Solution by Ion Flotation Using Rhamnolipid Biosurfactant As an Ion Collector

“…Studies of flotation kinetics are useful in elucidating the mechanism of the process and serve as predictive tools in the implementation of flotation technology. Chemical kinetics principles have been used in the modeling of flotation processes, particularly in the formulation of the basic rate equation. , Studies of the kinetics of ion flotation have been carried out by different investigators, and the process has been shown to follow the first-order equation − k = prefix− c normali − c normalr c normali t nobreak0em0.25em⁡ ln nobreak0em.25em⁡ c − c normalr c normali − c normalr where k is the kinetic rate constant; t is the flotation time; and c i , c r , and c are the initial, residual, and time-dependent ion concentrations in solution, respectively. The rate constant, k , can be estimated by a correct data fitting of c values against flotation time.…”

ADSORPTIVE BUBBLE SEPARATION METHODS—Foam Fractionation and Allied Techniques

“…With appropriate collectors, concentration by ion flotation of the fluorozirconate ion (777) and the ions of europium, cesium, and strontium has been reported and compared favorably with flocculation (77). The batch removal rates of lead, iron, and copper have been studied (115).…”

Effect of Coagulation on the Microflotation of Bacillus cereus

“…(1) to investigate the micro flotation of Bacillus cereus, which is larger and more hydrophobic than the other bacteria studied; (2) to determine the effect of coagulant concentration on the pH range of efficient microflotation; and (3) to examine the relative effectiveness of soluble and insoluble cationic and anionic collectors.…”