Sorption behavior of mercuric and methylmercuric salts on wool

Abstract

synopsisSorption by wool of mercuric nitrate, mercuric chloride, and methylmercuric chloride was measured by atomic absorption spectroscopy. Both inorganic mercury compounds are efficiently taken up a t low concentrations from acid solution. The rate of binding from the nitrate is appreciably slower than from the chloride. Methylmercuric chloride is bound slowly at low pH, rapidly at p H 6. The extent of its binding is roughly 10% to 20% of that of the inorganic salts. The wool-bound mercury can be recovered by serial extraction with aqueous citrate or ethylenediaminetetraacetate a t pH 6. The residual, firmly bound mercury is roughly equivalent to the sulfhydryl sulfur. Sorption of inorganic mercury compounds a t low pH roughly follows a Freundlich isotherm in the concentration range 5 X lo6 to 10-lM. Sorption of methylmercuric chloride at pH 6 follows a roughly parallel isotherm in the range 5 X to 10-3M. These datasuggest the potential value of wool and other animal keratins to remove and recover mercury from contaminated water. Wool may also serve as an instructive model for mercury binding and release in the body.

Interaction of Wool Kerateine and Its Derivatives With Heavy Metal Ions. I. Preparation and Properties of Crosslinked Kerateine-Gels

“…4 shows a maximum uptake around pH 2.5 and then a gradual increase in the uptake at pH values higher than 5, while that for native wool shows distinctly lower uptakes than WG-T5 throughout the whole range of pH. The result for native wool is in good agreement with that already reported by Friedman et al 9 Now it is obvious that the adsorption mechanism of Hg2+ is different for different pH region and that Hg 2+ can be captured by the gel most effectively from neutral (or slightly basic) aqueous media. The latter characteristics of the kerateine gel is quite advantageous from the standpoint of removing Hg2+ from industrial waste water, since no adjustment of pH of waste water, after treated with the gel, is necessary before the exhausting.…”

Removal of some heavy metal ions from aqueous solution by adsorption using poly(ethylene terephthalate)-g-itaconic acid/acrylamide fiber

“…Such sorbents have a larger specific surface area and very small diameter, assuring high kinetic properties, such as adsorption and concentration procedures become more convenient and easier [4]. Active carbon, metal oxides, peanut skins, wool, and cotton [5][6][7][8] have been used as adsorbents for adsorption of heavy metal ions. Reactive polymers are another group of materials that are used in the selective extraction of metals from aqueous solutions [9][10][11].…”

Use of waste wool for the removal of mercury from industrial effluents, particularly those from the chlor‐alkali industry

“…In all cases the Hg sorption is complete within two hours with wool combing waste and wool carpet waste showing s= 90 percent exhaustion of the total Hg present. The rates of sorption obey a Freundlich type adsorption isotherm, as observed by Friedman and coworkers, 14 i.e. log 10 x = + a log 10 c + b…”

“…However, the linear relationship only holds over a limited range and the usefulness of such extrapolations is doubtful. For example, by extrapolation, Friedman 14 predicted that the reduction of 1 dm 3 of a 138 ppmHg solution to the 0.005 ppm level would require lOOg wool. However, from the results presented in Figure 1, which are typical of all the wool samples, increasing the quantity of wool above a certain wool-liquor ratio produces no further substantial removal of mercury.…”