Crosslinked polydithiocarbamate, synthesis thereof, and use for removing heavy metals

Patent metadata

Field	Value
Publication number	US-10494472-B2
Application number	US-201715856751-A
Country	US
Kind code	B2
Filing date	Dec 28, 2017
Priority date	Dec 28, 2017
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

Crosslinked polydithiocarbamates based on 1,3,5-triazinane cores linked to pyrrole-dithiocarbamates via alkyl chains. A process for preparing these crosslinked polydithiocarbamates via a Mannich-type polycondensation of diaminoalkane, paraformaldehyde and a pyrrole compound, which is followed by additional modification of the pyrrole moiety to a pyrrole-dithiocarbamate. A method for removing heavy metals, such as Cd(II) from an aqueous solution or an industrial wastewater sample with these crosslinked polydithiocarbamates is also described.

First claim

The invention claimed is:

1. A crosslinked polydithiocarbamate of Formula (I)

or a salt thereof, a solvate thereof, a tautomer thereof, a stereoisomer thereof, or a mixture thereof;
wherein, R 1 is selected from the group consisting of a hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, and an optionally substituted arylalkyl;
each R 2 is independently selected from the group consisting of a hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted alkoxy, an optionally substituted aryl, an optionally substituted arylalkyl, an optionally substituted aryloxy, and a halogen;
R 3 is selected from the group consisting of a hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, and an optionally substituted arylalkyl;
X is an alkali metal cation;
n is a positive integer in the range of 2-16;
m is a positive integer in the range of 2-10000;
A 1 forms a bond to A 2 of another monomer unit; and
each A 3 is independently a hydrogen, or forms a bond to A 1 of another monomer unit.

2. The crosslinked polydithiocarbamate of claim 1 , which is

or a salt thereof, a solvate thereof, or a mixture thereof;
wherein, X is an alkali metal cation;
n is a positive integer in the range of 2-10;
m is a positive integer in the range of 2-10000;
A 1 forms a bond to A 2 of another monomer unit; and
each A 3 is independently a hydrogen, or forms a bond to A 1 of another monomer unit.

3. The crosslinked polydithiocarbamate of claim 1 , wherein X is K.

4. The crosslinked polydithiocarbamate of claim 1 , which exhibits a semi-crystalline structure.

5. A method of synthesizing the crosslinked polydithiocarbamate of claim 1 , comprising:
reacting a diaminoalkane of Formula (V)

or a salt, solvate, tautomer or stereoisomer thereof, with a pyrrole compound of Formula (VI)

or a salt, solvate, tautomer or stereoisomer thereof, and paraformaldehyde to form a crosslinked polymeric resin, wherein:
R 1 is selected from the group consisting of a hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, and an optionally substituted arylalkyl,
R 3 is selected from the group consisting of a hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, and an optionally substituted arylalkyl,

each R 2 is independently selected from the group consisting of a hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted alkoxy, an optionally substituted aryl, an optionally substituted arylalkyl, an optionally substituted aryloxy, and a halogen, and
n is a positive integer in the range of 2-16; and
reacting the crosslinked polymeric resin with carbon disulfide in the presence of an alkali metal hydroxide to form the crosslinked polydithiocarbamate.

6. The method of claim 5 , wherein a molar ratio of the paraformaldehyde to the pyrrole compound is in the range of 1:1 to 10:1.

7. The method of claim 5 , wherein a molar ratio of the diaminoalkane to the pyrrole compound is in the range of 1:1 to 5:1.

8. The method of claim 5 , wherein each R 1 , R 2 and R 3 is a hydrogen, n is selected from 2, 4, 8 and 10, and wherein the pyrrole compound is pyrrole, and the diaminoalkane is at least one selected from the group consisting of 1,2-diaminoethane, 1,4-diaminobutane, 1,8-diaminooctane, and 1,10-diaminodecane.

9. A method for removing a heavy metal from an aqueous solution, comprising:
contacting the aqueous solution having an initial concentration of the heavy metal with the crosslinked polydithiocarbamate of claim 1 to form a mixture; and
filtering the mixture to obtain a heavy metal loaded crosslinked polydithiocarbamate and an aqueous solution having a reduced concentration of the heavy metal compared to the initial concentration.

10. The method of claim 9 , wherein the heavy metal is an ion of at least one heavy metal selected from the group consisting of Pb, Cd, As, Cu, Ni, Co, Mn, and Cr.

11. The method of claim 9 , wherein the heavy metal is Cd(II).

12. The method of claim 9 , wherein the aqueous solution has a pH in the range of 2 to 8.

13. The method of claim 9 , wherein the initial concentration of the heavy metal in the aqueous solution ranges from 50 μg L −1 to 5000 μg L −1 .

14. The method of claim 9 , wherein the crosslinked polydithiocarbamate is present at a concentration in the range of 0.1-10 g per liter of the aqueous solution during the contacting.

15. The method of claim 9 , wherein the crosslinked polydithiocarbamate is contacted with the aqueous solution for 0.1-24 hours.

16. The method of claim 9 , wherein the crosslinked polydithiocarbamate is contacted with the aqueous solution at a temperature in the range of 20° C. to 80° C.

17. The method of claim 9 , wherein the crosslinked polydithiocarbamate has an adsorption capacity in the range of 100-5000 μg of heavy metal per gram of the crosslinked polydithiocarbamate.

18. The method of claim 9 , wherein greater than 30% of a total mass of the heavy metal is removed from the aqueous solution.

19. The method of claim 9 ,
wherein each R 1 , R 2 , and R 3 is a hydrogen, and n is 2;
wherein the aqueous solution comprises Cd(II) and at least one additional heavy metal ion, which is an ion of at least one heavy metal selected from the group consisting of Pb, As, Cu, Ni, Co, Mn, and Cr, and
wherein greater than 95% of a total mass of Cd(II) is removed from the aqueous solution.

20. The method of claim 9 , further comprising:
treating the heavy metal loaded crosslinked polydithiocarbamate with an acid to desorb the heavy metal and form a regenerated crosslinked polydithiocarbamate; and
using the regenerated crosslinked polydithiocarbamate to remove a heavy metal from an aqueous solution.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Al Hamouz Othman Charles Sadeq
• Estatie Mohammed
• Awadh Tawfik Abdo Saleh

Classifications

• C08L75/04

  Polyurethanes · CPC title

• C08F226/00

  Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen · CPC title

• C02F2101/22

  Chromium or chromium compounds, e.g. chromates · CPC title

• C08G18/3859 Primary

  containing -N-C=S groups · CPC title

• C08K3/30

  Sulfur-, selenium- or tellurium-containing compounds · CPC title