CN115608343B - Method for regenerating water-absorbent resin and regenerated water-absorbent resin - Google Patents
Method for regenerating water-absorbent resin and regenerated water-absorbent resin Download PDFInfo
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- CN115608343B CN115608343B CN202110923049.4A CN202110923049A CN115608343B CN 115608343 B CN115608343 B CN 115608343B CN 202110923049 A CN202110923049 A CN 202110923049A CN 115608343 B CN115608343 B CN 115608343B
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- Prior art keywords
- water
- absorbent resin
- regenerating
- resin
- metal salt
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- 229920005989 resin Polymers 0.000 title claims abstract description 187
- 239000011347 resin Substances 0.000 title claims abstract description 187
- 239000002250 absorbent Substances 0.000 title claims abstract description 169
- 238000000034 method Methods 0.000 title claims abstract description 48
- 230000001172 regenerating effect Effects 0.000 title claims abstract description 30
- 229910021645 metal ion Inorganic materials 0.000 claims abstract description 78
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 55
- 238000010521 absorption reaction Methods 0.000 claims abstract description 50
- 239000002516 radical scavenger Substances 0.000 claims abstract description 43
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 41
- 208000005156 Dehydration Diseases 0.000 claims abstract description 32
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 32
- 230000018044 dehydration Effects 0.000 claims abstract description 31
- -1 phosphonic acid compound Chemical class 0.000 claims description 58
- 150000003839 salts Chemical class 0.000 claims description 38
- 229910052751 metal Inorganic materials 0.000 claims description 30
- 239000002184 metal Substances 0.000 claims description 30
- 239000000843 powder Substances 0.000 claims description 18
- 238000001035 drying Methods 0.000 claims description 14
- 239000012047 saturated solution Substances 0.000 claims description 14
- 229920002536 Scavenger resin Polymers 0.000 claims description 9
- 239000004745 nonwoven fabric Substances 0.000 claims description 8
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 6
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims description 6
- 239000001110 calcium chloride Substances 0.000 claims description 6
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 6
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 claims description 6
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Chemical compound [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 claims description 6
- 238000002242 deionisation method Methods 0.000 claims description 5
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 claims description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 3
- 150000001450 anions Chemical class 0.000 claims description 3
- 229910001629 magnesium chloride Inorganic materials 0.000 claims description 3
- 125000001302 tertiary amino group Chemical group 0.000 claims 1
- 230000002745 absorbent Effects 0.000 abstract description 24
- 238000011069 regeneration method Methods 0.000 abstract description 22
- 230000008929 regeneration Effects 0.000 abstract description 11
- 229920006395 saturated elastomer Polymers 0.000 abstract description 5
- 150000001340 alkali metals Chemical class 0.000 abstract description 4
- 239000012266 salt solution Substances 0.000 abstract description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 25
- 125000004430 oxygen atom Chemical group O* 0.000 description 15
- 229920000247 superabsorbent polymer Polymers 0.000 description 12
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 11
- 239000011780 sodium chloride Substances 0.000 description 11
- 159000000000 sodium salts Chemical class 0.000 description 11
- 229920002125 Sokalan® Polymers 0.000 description 9
- 239000007864 aqueous solution Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 9
- 239000008367 deionised water Substances 0.000 description 9
- 229910021641 deionized water Inorganic materials 0.000 description 9
- 239000004584 polyacrylic acid Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 125000000524 functional group Chemical group 0.000 description 7
- 239000002253 acid Substances 0.000 description 6
- 238000001914 filtration Methods 0.000 description 6
- 238000006386 neutralization reaction Methods 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 230000002378 acidificating effect Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 239000006096 absorbing agent Substances 0.000 description 4
- 239000003513 alkali Substances 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 238000004064 recycling Methods 0.000 description 4
- PQUXFUBNSYCQAL-UHFFFAOYSA-N 1-(2,3-difluorophenyl)ethanone Chemical compound CC(=O)C1=CC=CC(F)=C1F PQUXFUBNSYCQAL-UHFFFAOYSA-N 0.000 description 3
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 150000002500 ions Chemical group 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 229940047670 sodium acrylate Drugs 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 229910052723 transition metal Inorganic materials 0.000 description 3
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 2
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 238000010306 acid treatment Methods 0.000 description 2
- 239000008280 blood Substances 0.000 description 2
- 210000004369 blood Anatomy 0.000 description 2
- 229910001424 calcium ion Inorganic materials 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 210000003608 fece Anatomy 0.000 description 2
- 239000002657 fibrous material Substances 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 2
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 2
- 230000002175 menstrual effect Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 239000005022 packaging material Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000002985 plastic film Substances 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 2
- 150000003512 tertiary amines Chemical group 0.000 description 2
- 210000002700 urine Anatomy 0.000 description 2
- BAERPNBPLZWCES-UHFFFAOYSA-N (2-hydroxy-1-phosphonoethyl)phosphonic acid Chemical compound OCC(P(O)(O)=O)P(O)(O)=O BAERPNBPLZWCES-UHFFFAOYSA-N 0.000 description 1
- LMHAGAHDHRQIMB-UHFFFAOYSA-N 1,2-dichloro-1,2,3,3,4,4-hexafluorocyclobutane Chemical compound FC1(F)C(F)(F)C(F)(Cl)C1(F)Cl LMHAGAHDHRQIMB-UHFFFAOYSA-N 0.000 description 1
- 229920002126 Acrylic acid copolymer Polymers 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 229940120146 EDTMP Drugs 0.000 description 1
- 206010021639 Incontinence Diseases 0.000 description 1
- QPCDCPDFJACHGM-UHFFFAOYSA-N N,N-bis{2-[bis(carboxymethyl)amino]ethyl}glycine Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(=O)O)CCN(CC(O)=O)CC(O)=O QPCDCPDFJACHGM-UHFFFAOYSA-N 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 206010040880 Skin irritation Diseases 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 description 1
- YDONNITUKPKTIG-UHFFFAOYSA-N [Nitrilotris(methylene)]trisphosphonic acid Chemical compound OP(O)(=O)CN(CP(O)(O)=O)CP(O)(O)=O YDONNITUKPKTIG-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 229910000288 alkali metal carbonate Inorganic materials 0.000 description 1
- 150000008041 alkali metal carbonates Chemical class 0.000 description 1
- 229910001514 alkali metal chloride Inorganic materials 0.000 description 1
- 229910001963 alkali metal nitrate Inorganic materials 0.000 description 1
- 229910052936 alkali metal sulfate Inorganic materials 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 210000001124 body fluid Anatomy 0.000 description 1
- 239000010839 body fluid Substances 0.000 description 1
- LOGBRYZYTBQBTB-UHFFFAOYSA-N butane-1,2,4-tricarboxylic acid Chemical compound OC(=O)CCC(C(O)=O)CC(O)=O LOGBRYZYTBQBTB-UHFFFAOYSA-N 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 239000012024 dehydrating agents Substances 0.000 description 1
- 229940090960 diethylenetriamine pentamethylene phosphonic acid Drugs 0.000 description 1
- DUYCTCQXNHFCSJ-UHFFFAOYSA-N dtpmp Chemical compound OP(=O)(O)CN(CP(O)(O)=O)CCN(CP(O)(=O)O)CCN(CP(O)(O)=O)CP(O)(O)=O DUYCTCQXNHFCSJ-UHFFFAOYSA-N 0.000 description 1
- NFDRPXJGHKJRLJ-UHFFFAOYSA-N edtmp Chemical compound OP(O)(=O)CN(CP(O)(O)=O)CCN(CP(O)(O)=O)CP(O)(O)=O NFDRPXJGHKJRLJ-UHFFFAOYSA-N 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 210000000416 exudates and transudate Anatomy 0.000 description 1
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 1
- 229910052808 lithium carbonate Inorganic materials 0.000 description 1
- INHCSSUBVCNVSK-UHFFFAOYSA-L lithium sulfate Inorganic materials [Li+].[Li+].[O-]S([O-])(=O)=O INHCSSUBVCNVSK-UHFFFAOYSA-L 0.000 description 1
- HQRPHMAXFVUBJX-UHFFFAOYSA-M lithium;hydrogen carbonate Chemical compound [Li+].OC([O-])=O HQRPHMAXFVUBJX-UHFFFAOYSA-M 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- MGFYIUFZLHCRTH-UHFFFAOYSA-N nitrilotriacetic acid Chemical compound OC(=O)CN(CC(O)=O)CC(O)=O MGFYIUFZLHCRTH-UHFFFAOYSA-N 0.000 description 1
- RGSFGYAAUTVSQA-UHFFFAOYSA-N pentamethylene Natural products C1CCCC1 RGSFGYAAUTVSQA-UHFFFAOYSA-N 0.000 description 1
- 229960003330 pentetic acid Drugs 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 150000003009 phosphonic acids Chemical class 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 1
- 229910000028 potassium bicarbonate Inorganic materials 0.000 description 1
- 235000015497 potassium bicarbonate Nutrition 0.000 description 1
- 239000011736 potassium bicarbonate Substances 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 235000011181 potassium carbonates Nutrition 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 159000000001 potassium salts Chemical class 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 235000011151 potassium sulphates Nutrition 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000001223 reverse osmosis Methods 0.000 description 1
- 230000036556 skin irritation Effects 0.000 description 1
- 231100000475 skin irritation Toxicity 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
- 239000004317 sodium nitrate Substances 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- RBTVSNLYYIMMKS-UHFFFAOYSA-N tert-butyl 3-aminoazetidine-1-carboxylate;hydrochloride Chemical compound Cl.CC(C)(C)OC(=O)N1CC(N)C1 RBTVSNLYYIMMKS-UHFFFAOYSA-N 0.000 description 1
- 238000012549 training Methods 0.000 description 1
- 229920001567 vinyl ester resin Polymers 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/34—Regenerating or reactivating
- B01J20/3425—Regenerating or reactivating of sorbents or filter aids comprising organic materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
- B01J20/26—Synthetic macromolecular compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/34—Regenerating or reactivating
- B01J20/345—Regenerating or reactivating using a particular desorbing compound or mixture
- B01J20/3475—Regenerating or reactivating using a particular desorbing compound or mixture in the liquid phase
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
- B29B2017/0213—Specific separating techniques
- B29B2017/0268—Separation of metals
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Mechanical Engineering (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
The present invention relates to a method for regenerating a water-absorbent resin and a regenerated water-absorbent resin. The regeneration method includes a first dehydration treatment, a deionized treatment, a removal treatment, and a second dehydration treatment. By means of the specific volume ratio of the saturated alkali metal salt solution to the demetallized resin, the regeneration process can eliminate the complex formed by the bivalent metal ion and the metal ion scavenger, and this can raise the absorption performance of the regenerated water absorbent resin.
Description
Technical Field
The present invention relates to a method for regenerating a water-absorbent resin and a regenerated water-absorbent resin, and more particularly, to a method for regenerating a water-absorbent resin and a regenerated water-absorbent resin capable of improving absorption performance.
Background
The water-absorbent resin is often used in disposable sanitary articles for absorbing and retaining human body exudates, such as urine, feces and menstrual blood, including disposable diapers, training pants, adult incontinence and feminine hygiene articles. In terms of the structure of the sanitary article, the sanitary article comprises a liquid-pervious topsheet facing the body of the user, a liquid-impervious backsheet facing the clothing of the user, and an absorbent core disposed between the topsheet and the backsheet, and the absorbent core is composed of a water-absorbent resin. Furthermore, disposable sanitary articles offer good comfort and convenience to the user, especially the advantage of being disposable immediately after use, and are therefore widely used by the public.
Although the disposable sanitary articles have the above convenience, the disposable sanitary articles after use have serious environmental problems with the increase of the use amount and frequency. In detail, the disposable sanitary article after use is stained with dirt of feces, urine, body fluid or menstrual blood, and the dirt contains moisture and is retained by the absorbent core, so that it is difficult to incinerate in the incinerator, and even the life of the incinerator is shortened. Second, the weight of disposable sanitary products increases greatly after use, and is disadvantageous for transportation to incinerators or landfills. Furthermore, disposable sanitary products contain many chemical materials (mainly water-absorbent resins) which are not easily decomposed, and are not easily decomposed in landfills.
In order to improve the aforementioned disadvantages of the disposable sanitary products, recycling of the disposable sanitary products has been studied. For example, taiwan patent publication No. I630959 discloses a method for recycling absorbent articles. The recovery method comprises the steps of cleaning dirt on the absorbent article, dehydrating the absorbent article in a high-tension solution, crushing the dehydrated absorbent article, and recovering the absorbent material, the fiber material and the packaging material according to the specific gravity difference of the absorbent material, the fiber material and the packaging material in the absorbent article.
Taiwan patent publication No. I652124 discloses a full-automatic paper diaper recycling system, which comprises an automatic cleaning device, a crusher and a precipitation separation device. The automatic cleaning equipment can clean, disinfect and sterilize the paper diaper after use, and the crusher can cut the paper diaper after cleaning to form a size which is easy to separate. The precipitation separation device can utilize a solvent (a super absorbent absorber dehydrating agent) to dehydrate and crystallize the super absorbent absorber in the paper diaper, and the plastic sheet and the cotton fiber are separated from the super absorbent absorber due to the relation of the solvent. Meanwhile, the materials forming the diaper are automatically layered in the solvent due to the weight difference, so that the materials can be collected individually according to the layering, and the aim of recycling is fulfilled. Although the use of an organic solvent can effectively dehydrate a super absorbent absorber, the organic solvent has a risk of safety in use and a disadvantage of recovering the organic solvent.
Further, japanese patent laid-open publication No. 2003-225645 discloses adding a transition metal salt, or a mixture of a transition metal salt and an alkali metal salt or an alkaline earth metal salt, to a gel-like mixture of a pulp component and a superabsorbent polymer contained in an absorbent article after use to remove moisture in the superabsorbent polymer, and shrinking and curing the superabsorbent polymer. Meanwhile, after the super absorbent polymer is colored by the transition metal salt, the pulp components and the super absorbent polymer are separated and recovered respectively. Then separating out the salts by acid treatment, and then carrying out alkali treatment on the super absorbent polymer after the acid treatment so as to recover the absorption performance of the super absorbent polymer. Acids and bases are corrosive to equipment and irritating to human skin. If residual acid or alkali is present in the regenerated superabsorbent polymer, the regenerated superabsorbent polymer cannot be applied to manufacturing paper diapers.
In addition, chinese patent publication No. CN104245119a discloses that the superabsorbent polymer after use is recovered by a simple and inexpensive regeneration method without using an acid or an alkali. The used super absorbent polymer is treated with an aqueous solution of a polyvalent metal salt and an aqueous solution of an alkali metal salt in sequence, and then washed with water and dried in sequence. The alkali metal salt aqueous solution can displace less calcium ions, and residual calcium ions react with the super absorbent polymer to reduce the absorption performance.
In view of the above, there is a need to develop a new method for regenerating a water-absorbent resin to improve the above-mentioned disadvantages of the known regenerated water-absorbent resin.
Disclosure of Invention
In view of the above, an aspect of the present invention is to provide a method for regenerating a water-absorbent resin. By means of the specific volume ratio of the saturated alkali metal salt solution to the demetallized resin, the regeneration process can eliminate the complex formed by the bivalent metal ion and the metal ion scavenger, and this can raise the absorption performance of the regenerated water absorbent resin.
Another aspect of the present invention is to provide a regenerated water-absorbent resin. The regenerated water-absorbent resin is produced by the aforementioned method for regenerating a water-absorbent resin.
According to an aspect of the present invention, a method for regenerating a water-absorbent resin is provided. In this regeneration method, the water-absorbent resin to be treated is subjected to a first dehydration treatment using a divalent metal salt to obtain a dehydrated resin. And then the dehydrated resin is subjected to deionization treatment by using a metal ion scavenger to obtain the demetallized resin. After the deionization treatment, a removal treatment is performed using a saturated solution containing an alkali metal salt to remove the metal ion scavenger and obtain a scavenger resin, wherein the volume ratio of the saturated solution to the scavenger resin is greater than 0.5 and less than 6.0. Then, the decollent resin is subjected to a second dehydration treatment using a powder of an alkali metal salt to obtain a regenerated water-absorbent resin.
According to an embodiment of the present invention, the divalent metal salt is at least one selected from the group consisting of calcium chloride, magnesium chloride, calcium nitrate and magnesium nitrate.
According to another embodiment of the present invention, the divalent metal salt is used in an amount of 5 mole percent to 25 mole percent based on 100 mole percent of the water-absorbent resin to be treated.
According to yet another embodiment of the present invention, the metal ion scavenger comprises a phosphonic acid compound, a carboxylic acid compound and alkali metal salts thereof.
According to yet another embodiment of the present invention, the metal ion scavenger comprises tertiary amine groups.
According to still another embodiment of the present invention, the metal ion scavenger is used in an amount of 1 mole percent to 20 mole percent based on 100 mole percent of the water absorbent resin to be treated.
According to yet another embodiment of the present invention, the anion of the alkali metal salt is selected from at least one of the group consisting of chloride, sulfate, nitrate, carbonate and bicarbonate.
According to still another embodiment of the present invention, the powder of the alkali metal salt is used in an amount of more than 0.3 mole percent and less than 35 mole percent based on 100 mole percent of the water-absorbent resin to be treated.
According to still another embodiment of the present invention, after the second dehydration treatment, the regenerating method further comprises a drying treatment to dry the regenerated water-absorbent resin.
Another aspect of the present invention provides a regenerated water-absorbent resin. The regenerated water-absorbent resin is produced by the aforementioned method for regenerating a water-absorbent resin, wherein the regenerated water-absorbent resin has a water absorption capacity of not less than 85% according to the method of ERT 440.3 (10) prescribed by European nonwoven fabrics Association.
The method for regenerating a water-absorbent resin according to the present invention comprises a first dehydration treatment, a deionized treatment, a removal treatment and a second dehydration treatment. By means of the specific volume ratio of the saturated alkali metal salt solution to the demetallized resin, the regeneration process can eliminate the complex formed by the bivalent metal ion and the metal ion scavenger, and this can raise the absorption performance of the regenerated water absorbent resin.
Drawings
For a more complete understanding of embodiments of the present invention and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings. It must be emphasized that the various features are not drawn to scale and are for illustration purposes only.
The related drawings are described as follows:
FIG. 1 is a schematic flow chart of a method for regenerating a water-absorbent resin according to an embodiment of the present invention.
Detailed Description
The making and using of the embodiments of the present invention are discussed in detail below. However, it is to be understood that the embodiments provide many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The particular embodiments discussed are merely illustrative and are not meant to limit the scope of the invention.
The method for regenerating a water-absorbent resin according to the present invention comprises a first dehydration treatment, a deionized treatment, a removal treatment, and a second dehydration treatment. In other words, the divalent metal ion forms a coordinate bond with an oxygen atom of a carboxyl group of the water-absorbent resin to be treated, and replaces a water molecule that is originally bonded to the oxygen atom by a hydrogen bond, thereby performing dehydration treatment to obtain a dehydrated resin. And removing the divalent metal ions in the dehydrated resin by using a metal ion scavenger to obtain the metal ion-removed resin. Then, removing the metal ion scavenger in the metal ion scavenger resin by using a saturated solution of alkali metal salt to obtain the scavenger resin, wherein the complex formed by the divalent metal ion and the metal ion scavenger is removed by using a specific volume ratio of the saturated solution of alkali metal salt and the metal ion scavenger resin. Then, the water in the aforementioned scavenger resin was permeated out with an alkali metal salt powder to obtain a regenerated water-absorbent resin. The water-absorbent resin regenerated by this regeneration method has good absorption properties.
The term "absorbency" as used herein refers to the absorbency of a regenerated and/or treated water-absorbent resin as measured by deionized water absorbency test and absorbency under pressure test with reference to ERT 440.3 (10) and ERT 442.3 (10) of the European nonwoven fabric Association (European Disposables And Nonwovens Association, EDANA), and the absorbency of the water-absorbent resin is evaluated based on the results obtained. If the water-absorbent resin has a deionized water absorption capacity of not less than 85% and a water absorption capacity under pressure of not less than 80%, the water-absorbent resin is said to have good absorption performance. The aforementioned pressure may be 4.9kPa.
Referring to fig. 1, a flow chart of a method for regenerating a water-absorbent resin according to an embodiment of the invention is shown. The water-absorbent resin regenerating method 100 subjects the water-absorbent resin to be treated to a first dehydration treatment using a divalent metal salt to obtain a dehydrated resin, as shown in operation 110. The divalent metal ions in the divalent metal salt form coordinate bonds with oxygen atoms of carboxyl groups of the water-absorbent resin to be treated, and replace water molecules which are originally bonded with the oxygen atoms through hydrogen bonds, so that dehydration is achieved.
In some embodiments, the water-absorbent resin may comprise crosslinked polyacrylic acid, a co-alkalized copolymer of a vinyl ester and an unsaturated carboxylic acid, a starch-acrylic acid copolymer, an isobutylene-maleic acid copolymer, and potassium or sodium salts of such polymers. Preferably, the water-absorbent resin may be a sodium salt of a crosslinked polyacrylic acid.
In some embodiments, the sodium salt of the crosslinked polyacrylic acid may have a neutralization degree (or neutralization rate) of 60 to 80 mole percent, and preferably may be 50 to 75 mole percent. The degree of neutralization is measured by methods known to those skilled in the art to which the present invention pertains. When the sodium salt of the crosslinked polyacrylic acid has the aforementioned degree of neutralization, the sodium salt of the crosslinked polyacrylic acid may have neutral or slightly acidic properties, and may provide comfort to human skin. The method 100 for regenerating a water-absorbent resin is particularly suitable for regenerating a water-absorbent resin having a sodium salt of polyacrylic acid having such a degree of neutralization.
In some embodiments, the divalent metal salt is selected from at least one of the group consisting of calcium chloride, magnesium chloride, calcium nitrate, and magnesium nitrate. When other dehydrating agents (non-divalent metal salts) are used in the regeneration method, the dehydrating agents tend to remain in the dehydrated resin. In addition, the regeneration method of the water-absorbent resin of the present invention eliminates the use of monovalent metal salts (e.g., sodium chloride) for the first dehydration of the water-absorbent resin to be treated, because the monovalent metal salts cannot stably replace water molecules that would otherwise be bound to oxygen atoms of the carboxyl groups of the water-absorbent resin, and cannot achieve the dehydration effect. In some embodiments, the divalent metal salt may be mixed with the water absorbent resin via an aqueous solution or in a powdery form to effect dehydration.
In other words, after the water-absorbent resin absorbs the liquid (for example, after the water-absorbent resin is used), the oxygen atoms of the carboxyl groups in the water-absorbent resin are negatively charged, and hydrogen bonds with water molecules, thereby achieving the water absorption effect. When the divalent metal salt is mixed with the water-absorbent resin, the divalent metal ion of the divalent metal salt forms a coordinate bond with the oxygen atom of the carboxyl group of the water-absorbent resin, and the oxygen atom releases water molecules, i.e., the water-absorbent resin to be treated is dehydrated.
In some embodiments, the dehydrated water absorbent resin (i.e., dehydrated resin) is shrunk, solidified and gradually precipitated, so that the water may be separated by filtration or centrifugation. In some embodiments, the dehydration process may be terminated based on the occurrence of the aforementioned precipitation phenomenon. In some applications, the dehydrated resin shrinks and cures, separating from the pulp and plastic film. After the dehydrated resin gradually precipitates, the dehydrated resin is separated by the specific gravity difference.
In some embodiments, the divalent metal salt may be used in an amount of 5 to 25 mole percent, and preferably may be 10 to 20 mole percent, based on 100 mole percent of the water-absorbent resin to be treated. When the amount of the divalent metal salt used is in the aforementioned range, the water-absorbent resin to be treated can rapidly and completely remove water. When the amount of the divalent metal salt used is in the aforementioned range, the water-absorbent resin to be treated can rapidly and completely remove water.
In some embodiments, the divalent metal salt may be used in an amount of 10 to 50 mole percent, and preferably may be 10 to 20 mole percent, based on 100 mole percent of the sodium salt of the crosslinked polyacrylic acid (calculated as 94g/mole of molecular weight of sodium acrylate). When the amount of the divalent metal salt used is in the aforementioned range, the water-absorbent resin to be treated can rapidly and completely remove water.
Following operation 110 described previously, the dehydrated resin is deionized using a metal ion scavenger to obtain a deionized resin, as shown in operation 120. The functional group of the chemical structure of the metal ion scavenger can be coordinately bound with the divalent metal ion of the divalent metal salt to form a complex, and the binding force of the functional group is larger than the binding force of carboxyl of the water absorbent resin on the divalent metal ion, so that the metal ion scavenger can remove the divalent metal ion, and the water absorption capacity of the metal ion scavenger is recovered. In some embodiments, the functional groups of the chemical structure of the metal ion scavenger may comprise functional groups of phosphonic acids, carboxylic acids, and amines having lone pair electrons that may form coordinate bonds with divalent metal ions.
In some embodiments, the metal ion scavenger is formulated as an aqueous solution, added to the dehydrated resin, and mixed well, after a period of time, to provide coordination bonding of the functional groups of the metal ion scavenger with the divalent metal ions. In some embodiments, the length of this time may be determined according to the case where the water-absorbent resin is recovered, and after the water-absorbent resin is recovered, the liquid (containing the complex) that is not absorbed by the water-absorbent resin may be removed by filtration, thereby separating the divalent metal salt and/or the divalent metal ion. Specific examples of the foregoing aqueous solution concentrations may be, but are not limited to, 0.5 to 5 weight percent concentration (wt.%).
In some embodiments, the metal ion scavenger comprises a phosphonic acid compound, a carboxylic acid compound, and alkali metal salts thereof. When the metal ion scavenger contains the aforementioned compound and salts thereof, the metal ion scavenger can easily and completely remove divalent metal ions in the water-absorbent resin.
In some embodiments, the phosphonic acid compound may include aminotrimethylene phosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediamine tetramethylene phosphonic acid, diethylenetriamine pentamethylene phosphonic acid, 2-phosphonate butane-1, 2, 4-tricarboxylic acid, 2-hydroxyphosphonoacetic acid, polyamino polyether methylene phosphonic acid, and bis 1, 6-hexylene triamine pentamethylene phosphonic acid. In other embodiments, the carboxylic acid compound may comprise an amino group-containing carboxylic acid, which may comprise ethylenediamine tetraacetic acid, aminotriacetic acid, and diethylenetriamine pentaacetic acid.
In the foregoing embodiments, the alkali metal salts may include sodium salts and potassium salts. When the salts of the phosphonic acid compound and the carboxylic acid compound are sodium salt and potassium salt, the water-absorbent resin regeneration method does not require water washing treatment in the subsequent treatment, because the salts of the phosphonic acid compound and the carboxylic acid compound are neutral salts and are non-acidic substances. If the divalent metal ions in the water-absorbent resin are removed by using the acidic substance of the corresponding phosphoric acid or carboxylic acid, the acidic substance is washed with water to prevent the residual acidic substance from causing skin irritation to the user.
In some embodiments, the functional groups of the phosphonic acid compound and the carboxylic acid compound in the metal ion scavenger may comprise tertiary amine groups. Under the condition that the molecular weight of the compounds is not increased, the groups can lead the chemical structures of the compounds to have a plurality of functional groups which can form coordination bonds with divalent metal ions, so that the capability of removing the divalent metal ions of the compounds is improved, and the time of deionizing treatment is shortened.
In some embodiments, the metal ion scavenger is used in an amount of 1 to 20 mole percent, and preferably may be 5 to 10 mole percent, based on 100 mole percent of the water-absorbent resin to be treated. When the amount of the metal ion scavenger used is in the aforementioned range, divalent metal ions can be easily removed without leaving excessive metal ion scavenger.
In some embodiments, the metal ion scavenger may be used in an amount of 5 to 25 mole percent, and preferably may be 5 to 10 mole percent, based on 100 mole percent of the sodium salt of the crosslinked polyacrylic acid (calculated as 94g/mole of molecular weight of sodium acrylate). When the amount of the metal ion scavenger used is in the aforementioned range, divalent metal ions can be easily removed without leaving excessive metal ion scavenger.
Following operation 120 described previously, a removal process is performed using a saturated solution containing an alkali metal salt to remove the metal ion scavenger and obtain a scavenger resin, as shown in operation 130. In other words, the water-absorbent resin is washed with a saturated solution containing an alkali metal salt to clean the above-mentioned composite remaining in the water-absorbent resin.
In some embodiments, the water-absorbent resin and the liquid not absorbed by the water-absorbent resin and containing the aforementioned composite may be separated by filtration to remove the residual metal ion scavenger in the water-absorbent resin.
The method for regenerating a water-absorbent resin according to the present invention eliminates the metal ion scavenger by removing the acid. In the conventional regeneration method of the water-absorbent resin, the metal ion scavenger is removed by using an acid, and therefore, the acid is neutralized with an alkali after the metal ion scavenger is removed, so that the skin of the user is prevented from being irritated by too low pH of the regenerated water-absorbent resin.
The method for regenerating a water-absorbent resin according to the present invention removes the metal ion scavenger by removing the unsaturated alkali metal salt aqueous solution. When the metal ion scavenger is removed in an aqueous alkali metal salt solution having an unsaturated concentration, the concentration of the alkali metal salt does not reach the saturated concentration, and therefore the divalent metal ions in the complex formed by the divalent metal ions and the metal ion scavenger are released, and the complex can form coordinate bonds with oxygen atoms of carboxyl groups of the water-absorbent resin again, so that the divalent metal ions remain in the water-absorbent resin, and the absorption performance of the water-absorbent resin after regeneration is lowered.
The volume ratio of the saturated solution to the water-absorbent resin after removal of the metal ions (i.e., the metal ion-removing resin) may be greater than 0.5 and less than 6.0. Preferably, the volume ratio may be 1 to 5. When the volume ratio is not more than 0.5, it is difficult for the insufficient saturated solution to completely wash out the complex, and the divalent metal ions remain in the water-absorbent resin, so that the absorption performance of the water-absorbent resin after regeneration is lowered. The divalent metal ion forms a strong coordination bond with an oxygen atom of a carboxyl group of the water-absorbent resin, and after subsequent drying, the bond between the divalent metal ion and the oxygen atom is stronger, and the bond between the oxygen atom of the carboxyl group of the water-absorbent resin and a water molecule is suppressed, so that the absorption performance of the regenerated water-absorbent resin is reduced. When this volume ratio is not less than 6, since the water-absorbent resin has an excessively large volume expansion after water absorption and a high water content, the subsequent drying treatment is caused to be low in operability and energy consumption. Further, when the volume of the water-absorbent resin becomes large, the drying time increases and the drying temperature increases, which damages the structure of the water-absorbent resin and reduces the absorption performance of the regenerated water-absorbent resin.
In some embodiments, the anion of the alkali metal salt is selected from at least one of the group consisting of chloride, sulfate, nitrate, carbonate, and bicarbonate. Specific examples of the alkali metal salt include alkali metal chloride, alkali metal sulfate, alkali metal nitrate, alkali metal carbonate and alkali metal bicarbonate. For example, the alkali metal salt may be lithium chloride, sodium chloride, potassium chloride, lithium sulfate, sodium sulfate, potassium sulfate, lithium nitrate, sodium nitrate, potassium nitrate, lithium carbonate, sodium carbonate, potassium carbonate, lithium bicarbonate, sodium bicarbonate, and potassium bicarbonate.
After the aforementioned operation 130, the demetallized resin is subjected to a second dehydration treatment using the alkali metal salt powder to obtain a regenerated water-absorbent resin, as shown in operation 140. The powder of alkali metal salt can remove the water in the metal ion removing resin in a reverse osmosis mode, so that the absorption performance of the regenerated water absorbent resin is improved. In other words, the powdery alkali metal salt causes a great concentration difference between the inside and outside of the water-absorbent resin, so that moisture permeates out of the metal ion-removing resin. In some embodiments, the permeated moisture is absorbed by the powder of alkali metal salt and removed by filtration.
The concentration of the salt used in operation 140 (i.e., the second dehydration process) must be greater than the concentration of the salt used in operation 130 (i.e., the removal process) to achieve the re-dehydration effect, and the second dehydration process must use the salt (e.g., salt powder or salt particles) directly instead of the solution based on the saturated concentration of the salt used in the removal process. In other words, when the salt used in the second dehydration treatment is not a salt powder (or particles) but a solution thereof, the effect of dehydration is reduced, so that the absorption performance of the water-absorbent resin after regeneration is reduced.
The method for regenerating a water-absorbent resin according to the present invention eliminates polyvalent metal ions from salts used in the scavenger removal treatment (i.e., removal treatment) and salts used in the second dehydration treatment. The polyvalent metal ion forms a stronger coordinate bond with the oxygen atom of the carboxyl group of the water-absorbent resin (as compared with the monovalent metal ion), and in the subsequent drying treatment, the bond between the polyvalent metal ion and the oxygen atom is stronger in the drying, and the bond between the oxygen atom of the carboxyl group of the water-absorbent resin and the water molecule is suppressed, so that the absorption performance of the water-absorbent resin after the regeneration is lowered.
In some embodiments, the alkali metal salt powder is used in an amount of more than 0.3 mole percent and less than 35 mole percent, and preferably may be 10 mole percent to 30 mole percent, based on 100 mole percent of the water-absorbent resin to be treated. When the amount of the alkali metal salt powder to be used is within the above range, sufficient alkali metal salt is not liable to remain in water, and the dehydration effect is enhanced, and the water absorption capacity under pressure of the regenerated water-absorbent resin can be increased.
In some embodiments, the alkali metal salt powder may be used in an amount of 10 to 50 mole percent, and preferably may be 10 to 30 mole percent, based on 100 mole percent of the sodium salt of the crosslinked polyacrylic acid (calculated as 94g/mole of molecular weight of sodium acrylate). When the amount of the powder of the alkali metal salt to be used is within the above-mentioned range, the sufficient alkali metal salt can enhance the dehydration effect and can increase the absorption amount at the time of use of the regenerated water-absorbent resin.
In some embodiments, after the aforementioned operation 140, the water-absorbent resin regeneration method 100 may optionally include a drying process to dry the regenerated water-absorbent resin, as shown in operation 150. The drying treatment is to dry the water remaining in the regenerated water-absorbent resin to improve the absorption performance of the regenerated water-absorbent resin.
Another aspect of the present invention provides a regenerated water-absorbent resin. The regenerated water-absorbent resin is produced by the aforementioned regeneration method of the water-absorbent resin, wherein the deionized water absorption capacity of the regenerated water-absorbent resin is not less than 85%, and preferably not less than 90%, according to the method of ERT 440.3 (10) prescribed by European nonwoven fabrics Association. The regenerated water-absorbent resin having the deionized water absorption capacity in the aforementioned range can provide good absorption performance.
In some embodiments, the water absorbent resin after regeneration may have a water absorption capacity under pressure of not less than 80%, and preferably not less than 85%, according to the method of ERT 442.3 (10) prescribed by European nonwoven fabrics Association. The regenerated water-absorbent resin having the water absorption capacity under the pressure in the aforementioned range can provide good absorption performance.
The following examples are set forth to illustrate the practice of the invention and are not intended to limit the invention thereto, as various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention.
Preparation of regenerated Water-absorbent resin
Example 1
10G (i.e., 10.63 mmole) of the water-absorbent resin (product number BC283G, manufactured by Taiwan plastics industry Co., ltd., product number BC283G, which has a deionized water absorption capacity of 450 times, a water absorption capacity under pressure of 22 times, and a neutralization degree of 74%) of the regenerated water-absorbent resin of example 1 was added with 100 ml of 1.063mmole (i.e., 0.117G) of an aqueous solution of calcium chloride, and stirred for 10 minutes to obtain a dehydrated resin.
After preparing a 1% aqueous solution of ethylenediamine tetraacetic acid (manufactured by merck corporation), it was added to 160 ml of dehydrated water-absorbent resin, and the amount used was 0.532mmole (i.e., 0.155 g). After stirring for 10 minutes, to obtain a metal ion-removed resin, the resin was filtered, and then 80 ml of the water-absorbent resin was taken out and washed with a supersaturated aqueous sodium chloride solution. Then, after filtration, 0.062g (i.e., 1.063 mmole) of sodium chloride powder was added, stirred for 10 minutes, and after dehydration, filtration was further carried out, followed by drying in an oven at 150℃for 1 hour, to obtain a regenerated water-absorbent resin.
Examples 2 to 6 and comparative examples 1 to 4
Examples 2 to 6 and comparative examples 1 to 4 were each prepared as a regenerated water-absorbent resin in the same manner as in example 1. In examples 2 to 6 and comparative examples 1 to 4, the types and amounts of calcium chloride, metal ion scavenger and sodium chloride were changed, and the specific conditions thereof are shown in Table 1.
Comparative example 5
Comparative example A water-absorbent resin was produced after regeneration in the same manner as in example 1. In comparative example 5, the types and amounts of calcium chloride and sodium chloride were changed, and the deionization treatment and the second dehydration treatment were not performed, and the specific conditions thereof are shown in table 1.
Evaluation method
1. Deionized water absorption rate test
Deionized water absorption capacity test was performed with reference to the procedure ERT 440.3 (10) specified by the european nonwoven fabric institute, wherein only 0.9% saline was replaced with deionized water.
2. Water absorption under pressure (Absorption Against Pressure, AAP)
The water absorption capacity under pressure test was conducted in accordance with the procedure of ERT 442.3 (10) specified by the european nonwoven fabric institute, wherein the water absorption capacity under pressure was measured at 0.9% aqueous sodium chloride solution for 60 minutes at a pressure of 4.9kPa.
TABLE 1
Referring to Table 1, according to the results of the water absorption capacity and the water absorption capacity under pressure of deionized water, compared with comparative examples 1 and 2 using too little or too much saturated sodium chloride solution, each example uses enough sodium chloride solution (i.e., the volume ratio of saturated solution to demetallized resin is 1 to 5), and the regenerated water-absorbent resin prepared therefrom has good absorption performance. From this, it was found that it was difficult to completely wash out the complex with an insufficient amount of the saturated solution, and the divalent metal ions remained in the water-absorbent resin, so that the absorption performance of the water-absorbent resin after regeneration was lowered. In addition, the use of an excessive saturated sodium chloride solution causes an excessive volume expansion after water absorption and a high water content of the water-absorbent resin, and increases the drying time and drying temperature, so that the structure of the water-absorbent resin is destroyed and the absorption performance of the regenerated water-absorbent resin is lowered.
Second, each example uses sufficient sodium chloride powder (i.e., 10 to 30 mole percent) as compared to comparative examples 3 and 4 using too little or too much sodium chloride powder, and the resulting regenerated water-absorbent resin can have good absorption properties. Therefore, enough sodium chloride powder can improve the dehydration effect and the water absorption rate under the pressure.
Further, the regenerated water-absorbent resin produced in each example had good absorption properties as compared with comparative example 5 in which the deionization treatment and the second dehydration treatment were not performed. From this, it was found that the residual divalent metal ions and moisture reduced the absorption performance of the water-absorbent resin after regeneration.
In summary, the regeneration method of the water-absorbent resin of the present invention uses the saturated solution of alkali metal salt to remove the metal ion-removing resin, and the specific volume ratio of the saturated solution to the metal ion-removing resin can remove the complex formed by the divalent metal and the metal ion scavenger, so that the regenerated water-absorbent resin has good absorption performance.
While the present invention has been described with reference to the above embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention, and the scope of the invention is defined by the appended claims.
[ symbolic description ]
100 method
110,120,130,140, 150.
Claims (9)
1. A method for regenerating a water-absorbent resin, characterized by comprising:
subjecting the water-absorbent resin to be treated to a first dehydration treatment using a divalent metal salt to obtain a dehydrated resin;
deionizing the dehydrated resin with a metal ion scavenger comprising a phosphonic acid compound, a carboxylic acid compound and alkali metal salts thereof to obtain a demetallized resin;
after the deionization treatment, removing the metal ion scavenger by using a saturated solution containing alkali metal salt, and obtaining a scavenger resin, wherein the volume ratio of the saturated solution to the scavenger resin is more than 0.5 and less than 6.0; and
the decollent resin is subjected to a second dehydration treatment using the powder of the alkali metal salt to obtain a regenerated water-absorbent resin.
2. The method for regenerating a water-absorbent resin according to claim 1, wherein the divalent metal salt is at least one selected from the group consisting of calcium chloride, magnesium chloride, calcium nitrate and magnesium nitrate.
3. The method for regenerating a water-absorbent resin according to claim 1, wherein the divalent metal salt is used in an amount of 5 to 25 mole percent based on 100 mole percent of the water-absorbent resin to be treated.
4. The method for regenerating a water-absorbent resin according to claim 1, wherein the metal ion scavenger comprises tertiary amine groups.
5. The method for regenerating a water-absorbent resin according to claim 1, wherein the metal ion scavenger is used in an amount of 1 to 20 mole percent based on 100 mole percent of the water-absorbent resin to be treated.
6. The method for regenerating a water-absorbent resin according to claim 1, wherein the anion of the alkali metal salt is at least one selected from the group consisting of chloride ion, sulfate ion, nitrate ion, carbonate ion and bicarbonate ion.
7. The method for regenerating a water-absorbent resin according to claim 1, wherein the powder of the alkali metal salt is used in an amount of more than 0.3 mol% and less than 35 mol% based on 100 mol% of the water-absorbent resin to be treated.
8. The method for regenerating a water-absorbent resin according to claim 1, further comprising a drying process for drying the regenerated water-absorbent resin after the second dehydration process.
9. A regenerated water-absorbent resin produced by the method for regenerating a water-absorbent resin according to any one of claims 1 to 8, wherein the water absorption capacity of the regenerated water-absorbent resin is not less than 85% according to ERT 440.3 (10) specified by the european nonwoven fabric co-produced.
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| CN104163936A (en) * | 2013-06-24 | 2014-11-26 | 利卫多株式会社 | Processing method for water-absorbing resin |
| CN104245119A (en) * | 2012-03-23 | 2014-12-24 | 国立大学法人北海道大学 | Method for reclaiming used superabsorbent polymer |
| JP2018034095A (en) * | 2016-08-30 | 2018-03-08 | 月島環境エンジニアリング株式会社 | Method for regenerating cation exchange resin, method for treating liquid to be treated, and treatment facility containing cation exchange resin |
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| CN104245119A (en) * | 2012-03-23 | 2014-12-24 | 国立大学法人北海道大学 | Method for reclaiming used superabsorbent polymer |
| CN104163936A (en) * | 2013-06-24 | 2014-11-26 | 利卫多株式会社 | Processing method for water-absorbing resin |
| JP2018034095A (en) * | 2016-08-30 | 2018-03-08 | 月島環境エンジニアリング株式会社 | Method for regenerating cation exchange resin, method for treating liquid to be treated, and treatment facility containing cation exchange resin |
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