DE2021629C - Ion exchange material for trapping metal ions from aqueous solutions - Google Patents

Description

A solution that ^{contains copper as Cu 2+} ions passes through a column of 1 kg of polyethyleneimine after acidification with hydrochloric acid, sulfuric acid or nitric acid to pH 4 or after the possibly more acidic solution has been buffered to this pH -Cellulose. This material sorbs copper and turns it blue. After washing the column with water, the cellulosic material is treated with a dilute mineral acid, e.g. B. with 2N hydrochloric acid. Here the sorbed copper is eluted again. From solutions of copper with a pH value of 4, Cu ^{2+ is} selectively sorbable and can be separated from high excess ions in the solution. This applies to the ions Zn ²⁴ , Ni ²⁺ , Co ²⁺ , Mg ²⁺ , Cd ²⁺ , Pb ²⁺ , Al ³⁺ , Fe ³⁺ . Cr ³⁺ .

Cu ²⁺ is sorbed by polyethyleneimine cellulose in the pH range 3 to 12, i.e. also from strongly aminoniacal solutions.

B e i s ρ i e 1 2

Scavenging vanadium as vanadate
from aqueous solution

A solution that contains vanadium as vanadate is optionally made by suitable additives Mineral acid or an alkali or a powder, such as alkali metal acetate, to a pH value set of 4. A column containing 1 kg of polyethyleneimine cellulose contains, sorbs 8.8 g of vanadium from this 6th solution. This can be done after washing the column with water with normal sulfuric acid or hydrochloric acid or with sodium or potassium hydroxide solution with a pH value of 9.5.

Example 3

Trapping of molybdenum as molybdate
from aqueous solution

The interception takes place as described in Example 2. It is eluted with 3 normal hydrochloric acid, which contains 1% Alkali metal rhodanide is added. Absorption capacity: 8.5 g molybdenum / kg polyethyleneimine cellulose. Molybdenum sorbed from such weakly acidic solutions can also be mixed with alkali lye or ammonia solution are desorbed in order to regenerate the ion exchange material.

Example 4

Trapping of tungsten as tungsten and molybdenum as molybdate from aqueous solution

A volume test solution between 1 and 10 1, which contains 15 g of tungsten as tungstate and 5 g of molybdenum as molybdate, after adjusting the pH brought into contact on 4 in a column with 1 kg of polyethyleneimine cellulose. Be in the run on average only 0.5% of the originally present tungsten and molybdenum were recovered. - The two metals can be eluted together with alkali lye above pH 10. One can but first the molybdenum with 3N hydrochloric acid, which contains about 1% alkali metal thiocyanate, Then the eluted tungsten with 0.01 to 1 normal alkali lye can also be used proceed with a solution which contains the metals vanadium, molybdenum and Wolir'-m.

Example 5
Scavenging palladium from aqueous solution

A hydrochloric acid solution containing palladium as a palladium (II) salt contains and the acidity of which can be between 0.1 and 10% HCl, passes through a column, which is charged with 1 kg of polyethyleneimine cellulose. After washing with water it is done Sorption of the palladium is recognizable by a yellow coloration of the cellulose material. The elution of the palla

S diums can be done with ammonia or hydrochloric acid aqueous solution of thiourea. The determination of the eluted palladium after sorption from 10% hydrochloric acid solutions results in a capacity of 10.4 g Pd / kg polyethyleneimine cellulose.

ίο Palladium can be separated from the ions Cu ² 'by sorption from at least normal hydrochloric acid solutions. Ni ²⁺ , Co ² +, Cd ²⁺ , Pb * +, Zn ²⁺ , Al ³ +, Fe ³⁺ , Cr ³⁺ can be separated.
• The ions Pt ⁴⁴ , Rh ³⁺ , Au ³⁺ and Co ² · or Co ³⁺ could also be trapped, to name further examples. From pH 4.8 cobalt is sorbed down to the neutral range, the elution of the Co ²⁺ succeeds with mineral acid already at pH 4, that of the Co ³⁺ not even with concentrated mineral acids; it will be

ao advantageously first ^{reduced to Co 2+} before it is eluted as indicated.

As the examples show, it is possible with the aid of the ion exchange material according to the invention to capture both metal cations and metal-containing anions from aqueous solution. Further great advantages of this ion exchange material according to the invention are its long service life, since the Sorption capacity does not decrease significantly even after numerous regeneration processes, as well as the surprisingly high sorption speed, which is of the order of 10 minutes.

The ion exchange material according to the invention is particularly important for intercepting the said metals from their aqueous solutions, for example in the field of wastewater treatment. It has also proven to be very good for the purification of one of the aforementioned metals from aqueous Solutions alongside the other metals as impurities.

Claims (5)

t! ι Claims: 1. Ion exchange material for scavenging Metal ions and / or ions containing metals, in particular of metals of the I., V., VI. and or VIII. Subgroup of the Periodic Table of the Elements, from aqueous solutions, marked through a carrier material made of cellulose, attached to the polyethyleneimine as an intercepting one Agent is bound, and at most a negligibly small one, by washing with water Contains no longer to be removed amount of unbound polyethyleneimine 2. ion exchange material according to claim 1, characterized in that the cellulose is natural, is lignin-depleted cellulose. 3. ion exchange material according to claim 2, characterized in that the cellulose is viscose cellulose (Rayon) is. 4. ion exchange material according to claim 2, characterized in that the Cel'ulose according to Copper silk is produced using the copper oxide-ammonia process. 5. ion exchange material according to claim 2, characterized in that the cellulose Chardonnese silk which is produced from nitrocellulose by reducing nitro groups has been. Cellulose is a material with the desired ion exchange properties. Natural, lignin-free cellulose or regenerated celluloses such as viscose cellulose (rayon) or "copper silk" produced by the copper oxide-ammonia process as well as the "Chardonnese silk" obtained from nitrocellulose by reducing the splitting off of nitro groups are preferably used.
The starting material of the aforementioned type is to deal with an aqueous, for example 5% Solution of polyethyleneimine. The reaction between the starting material and polyethyleneimine takes place in acidic, neutral or alkaline solution. The rate of reaction between the starting material and the polyethyleneimine depends on the Concentration, the pH of the solution, the type of starting material and its distribution, because it can be thread-like, powdery, spongy or compact. ao After the treatment with the aqueous polyethyleneimine solution, the resulting product is washed thoroughly with water in order to remove the unbound polyethyleneimine from it.
The ion exchange material produced in this way and containing bound polyethyleneimine is outstandingly suitable for solving the problem, namely for trapping metal ions and / or ions containing metals, in particular metals of the I., V., VI. and / or VIII. Subgroup of the Periodic Table of the Elements, from aqueous solutions, which is demonstrated by the following examples: example 1 To trap metal ions contained in aqueous solutions, precipitation reactions are usually carried out. In addition, gain, especially for very dilute solutions, ion exchange processes are becoming increasingly important. For example, it is from the German Offenlegungsschrift 1808 707 known rhenium from a solution, the rhenium and others Contains metals in an aqueous solvent to win. The rhenium is here selectively in jin Ion exchange medium transferred, then stripped with an aqueous thiocyanate solution. Furthermore, it is also known from US Pat. No. 2,876,065, a suitable anion exchange material, such as a strongly basic synthetic resin of alkylamine type, with rhenium and other contaminants To load metals in order to finally obtain rhenium in its pure form. According to suitable alkaline elution process is used to remove molybdenum and other contaminants the resin is rinsed and reapplied with a dilute solution of a strong mineral acid for removal eluted by rhenium. The object of the present invention is to provide ions containing metal ions and / or metals, especially of metals of the I., V., VI. and / or VIII. subgroup of the Periodic Table of the Elements, intercept from aqueous solutions. This object is achieved according to the invention by a carrier material made of cellulose, the polyethyleneimine is bound as an intercepting agent and that at most a negligibly small one, through Wash with water no longer contains an amount of unbound polyethyleneimine that can be removed. Starting material for the Ma- Trapping of copper from aqueous solution