JPS5823429B2 - Novel water-soluble polymer metal scavenger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel water-soluble polymeric metal scavenger that has an excellent scavenging effect on metals, particularly heavy metals.

Conventionally, heavy metal compounds contained in mine drainage, plating factory wastewater, etc. have various adverse effects on the human body, so it is necessary to completely remove them when discharging them into rivers or the like.

It is desirable to use metal scavengers that combine with heavy metal compounds to form inactive complexes and eliminate the harmful effects of the heavy metal compounds. All metal scavengers such as salts are expensive and are unsuitable for the treatment of mine drainage and industrial wastewater, which require use in large quantities.

Therefore, in the field of wastewater treatment technology, there has been a strong demand for the development of a metal trapping agent that can be industrially produced, can be manufactured at low cost, and has an excellent metal trapping effect.

As a result of extensive research in order to meet these demands, the present inventors have discovered that the purpose can be achieved using a condensation product of a polymer or copolymer of unsaturated carboxylic acid and a mercaptan having a functional group. Based on this finding, the present invention has been completed.

That is, the present invention comprises (a) a polymer or copolymer having a molecular weight of 100,000 to 400,000 and containing at least one α/β-unsaturated carboxylic acid ester as a constituent monomer, and (b)
A water-soluble polymeric metal scavenger comprising a condensation product of mercaptan having 1 to 10 moles of hydroxyl group-amino group or carboxyl group or 1 to 10 times mole of mercaptan having two thiol groups per mole of the monomer. It provides:

The polymers or copolymers used in the production of the metal scavenger of the present invention include α/β-unsaturated carboxylic acid esters, such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, It can be obtained by homopolymerizing or copolymerizing ethyl methacrylate, propyl methacrylate, butyl methacrylate, methyl crotonate, ethyl crotonate, propyl crotonate, butyl crotonate, etc. according to a conventional method.

In addition, other monomers copolymerizable with these α/β-unsaturated carboxylic acid esters, such as ethylene, ethylenically unsaturated monomers such as styrene, acrylamide, methacrylamide, and acrylics such as acrylonitrile. It is also possible to use polymers obtained by copolymerizing derivatives, halogenated vinyl compounds such as vinyl chloride, vinyl bromide, and vinylidene chloride, or diene compounds such as isoprene and butadiene.

These polymers must have a molecular weight of 100,000 to 400,000 as measured by a viscosity method.

As the mercaptan having a hydroxyl group, amine group or carboxyl group to be condensed with the above polymer or copolymer, α
- Thioglycerin, 2,3-dimercaptopropanol, 2-mercaptoethanol, 2-mercaptoethylamine, and cysteine.

In addition, 1.2-dimercaptoethane can also be used.

When reacting a raw material polymer with a mercaptan, 1 to 1 mercaptan is added per mole of α/β-unsaturated carboxylic acid ester monomer contained as a constituent monomer in the raw material polymer.
It is used at a ratio of 10 times the mole, preferably 3 to 6 times the mole.

The reaction is carried out at a temperature above room temperature, preferably from 50 to 150°C.

In order to carry out the reaction effectively, it is preferable to use a basic substance such as sodium hydroxide, potassium hydroxide, sodium alkoxide, potassium, or alkoxide as a catalyst in an amount of about 0.1 to 1 mole per mole of mercaptan.

As the solvent, it is preferable to use an aprotic polar solvent such as dimethylformamide or hexamethylphosphoric triamide.

The reaction time may be about 15 minutes to 200 minutes.

By appropriately setting the reaction conditions during the reaction, the number of ligands contained in the water-soluble polymeric metal scavenger produced can be adjusted.

Although the reaction product can be used as the metal trapping agent of the present invention without being separated as it is, it is also possible to separate the water-soluble polymeric metal trapping agent by dialysis.

The water-soluble polymeric metal scavenger of the present invention is a novel substance that is capable of dissolving metal compounds dissolved in wastewater, especially heavy metal compounds such as copper, nickel, cobalt, manganese, zinc, lead, cadmium, and mercury. Forms a complex and exhibits excellent trapping action.

When treating wastewater, it is desirable to use an amount of the ligand in the polymer that completely satisfies the coordination number of the metal present in the water.

When the water-soluble polymeric metal trapping agent of the present invention forms a complex with a metal in water, it exhibits a large foaming property, and when air is blown into the complex, it is adsorbed by air bubbles while remaining bound to the metal, and is removed and recovered.

In this way, even trace amounts of heavy metals present in water, such as several In9/l, can be easily removed and recovered.

The present invention uses mercaptan, which can be easily produced from sulfur currently produced in excess through petroleum desulfurization, as a raw material to provide a metal scavenger useful for wastewater treatment at a low cost, and has great industrial utility. It is something.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Methyl acrylate monomer 28.6 cm in a pressure glass reaction tube
P, add 3 oml of benzene, and add α・α as a polymerization initiator.
Add 0.15S'-azoisobutyronitrile and 60°
Polymerization was carried out at C for 3 hours.

The produced polymer was precipitated in 300 ml of methanol, and purified by repeating dissolution and precipitation with benzene-methanol.

After dissolving 1.3 g of polymethyl acrylate synthesized in this way in 48 m, l of dimethylformamide, α-
Thioglycerin 8.12 and sodium hydroxide 0.31 were added, and the mixture was reacted at 80°C for 30 minutes while stirring under reflux.

The reactant was dissolved in 120 ml of water and dialyzed against water using a cellulose membrane for 96 hours to remove unreacted α-thioglycerin and solvent, thereby obtaining a water-soluble polymeric metal scavenger.

- The reaction rate of all carboxylic acid esters was determined to be 3.7% by elemental analysis.

Nickel chloride aqueous solution 5077 containing nickel 10η/l
13 m9 of this water-soluble polymeric metal scavenger was added to No. 11, the pH of this aqueous solution was adjusted to 7, and 200 m1 of air per minute was sent through a ball filter from the bottom of a glass cylindrical tube with a diameter of 3 cm to perform foam treatment.

Through this treatment, more than 99% of nickel was removed and recovered.

Example 2 Polymethyl acrylate 1.3 obtained in the same manner as Example 1
A water-soluble polymeric metal scavenger was obtained by dissolving P in dimethylformamide 487711, adding 5.92 P of 2-mercaptoethanol and 0.3 P of sodium hydroxide, and reacting at 80°C for 30 minutes with stirring under reflux. Ta.

The reaction rate of all carboxylic acid esters was determined to be 2.4% from the elemental analysis values.

50r of manganese chloride aqueous solution containing 10Iv/l of manganese
This water-soluble polymeric metal scavenger 13~ was added to rLl, and air was blown in the same manner as described in Example 1 to perform foam treatment.

When the pH of the solution was 7, more than 99% of manganese was removed and recovered.

Example 3 Polymethyl acrylate 1.3 obtained in the same manner as Example 1
Dissolve 2 in 48ml of dimethylformamide and add 2 to this.
A water-soluble polymeric metal scavenger was obtained by adding 8.6 ml of -mercaptoethylamine hydrochloride and 3.31 ml of sodium hydroxide, and reacting at 80°C for 30 minutes with stirring under reflux.

The reaction rate of all carboxylic acid esters was determined to be 4.0% from the elemental analysis values.

Cadmium chloride aqueous solution containing cadmium 1ynq/l 5
5 m9 of this water-soluble polymeric metal scavenger was added to 0 ml, and air was blown in the same manner as described in Example 1 to perform foam treatment.

When the pH of the solution was 7, more than 99% of cadmium was removed and recovered.

Example 4 Polymethyl acrylate 1.3 obtained in the same manner as Example 1
1 was dissolved in 48 rrL of dimethylformamide, 7.11 l of 1,2-dimercaptoethane and 0.37 g of sodium hydroxide were added thereto, and the mixture was reacted at 80°C for 1 hour with stirring to obtain a water-soluble polymeric metal scavenger. I got it.

The reaction rate of all carboxylic acid esters was determined from elemental analysis values to be 15.4%.

Copper 101r! This water-soluble polymeric metal scavenger 13~ was added to 50 ml of an aqueous copper chloride solution containing 9/l, and air was blown in the same manner as described in Example 1 to perform foam treatment.

When the pH of the solution was 7, more than 99% of the copper was removed and recovered.

Claims (1)

[Scope of Claims] 1(a) a polymer or copolymer having a molecular weight of 100,000 to 400,000, containing at least one α/β-unsaturated carboxylic acid ester as a constituent monomer, and (b) the above-mentioned A water-soluble polymeric metal scavenger comprising a mercaptan having 1 to 10 moles of a hydroxyl group, an amino group, or a carboxyl group per mole of a simple substance, or a condensation product of a mercaptan having two thiol groups. 2 α/β-unsaturated carboxylic acid esters include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methyl methacrylate butinobecrotonate, and ethyl crotonate. , propyl crotonate, or butyl crotonate, the water-soluble polymeric metal scavenger according to claim 1. 3 Mercaptan is α-thioglycerin, 2,3-dimercaptopropanol, 2-mercaptoethanol,
2-mercaptoethylamine, cysteine or 1,2-
The water-soluble polymeric metal scavenger according to claim 1, which is dimercaptoethane.