CN101717471A - graft copolymer of starch and n-hydroxymethyl acrylamide - Google Patents

Abstract

The invention provides a graft copolymer of starch and N-hydroxymethyl acrylamide. The main chain of the graft copolymer is the starch; the branched chain of the graft copolymer is poly-N-hydroxymethyl acrylamide; part of the hydroxyl group on the branched chain is aminated into amino group or -NH-(C2H4NH)n-C2H4-NH2 and n is equal to 0 to 3; and the graft rate is 15 to 82 percent and the nitrogen content is 1 to 20 percent. The graft copolymer of the invention can be used as a metallic ion trapping agent, and the removing rate of heavy metal ion reaches over 99 percent when the graft copolymer is used for treating waste water containing the heavy metal ion.

Description

The graft copolymer of a kind of starch and N hydroxymethyl acrylamide

Technical field

The present invention relates to polymeric material field, be specifically related to graft copolymer.

Background technology

Along with the electronic industry fast development; the pollution becoming serious of heavy metal wastewater thereby and waste; seriously polluting existent environment of people; affect people's quality of life; also seriously restricting simultaneously the electronic industry development; thereby how to solve the plating pollution problem, and administer electroplating wastewater, become the task of top priority of field of environment protection.At present existing several different methods is used to remove heavy metal ion, as: ion exchange method, reverse osmosis method, absorption method, biological treatment etc., but owing to multiple reason, at present domestic and international prevailing, the most widely used chemical precipitation method that is still of heavy metal containing wastewater treatment technology.And chemical precipitation method processing electroplating effluent effect is undesirable, do not reach existing emission request, and have that processing efficiency is low, sediment weight greatly, easily causes secondary pollution problems, therefore the efficient chemical treatment medicament of development of new how is the emphasis that people study all the time.

Kai Fa macromolecular heavy metal chelating agent relies on the extremely strong huge legendary turtle of itself and metal to close ability in recent years, for electroplating wastewater improvement has brought new life, high-molecular chelating agent is to be parent with the macromolecular material, on its macromolecule matrix, introduce some by chemical reaction and have the group of metal-chelating performance, drop in the water can be immediately with water in heavy metal ion generation selectivity chelatropic reaction, generate water-fast metal complex, under the synergy of flocculation agent, the precipitation by metallic ion in the waste water is removed again.High-molecular chelating agent water-soluble makes it have that reaction is fast, characteristics such as consumption is little, selectivity is strong, eliminating efficiency height, enjoys users to favor.But because such rule of origin in synthesized polymer material, costs an arm and a leg, processed in units amount cost is too high, and has the residual monomer toxicity problem, is difficult to apply.

People such as Hu Chunhong have developed a kind of heavy metal chelant of nontoxic, cheap and biodegradable starch-containing skeleton; this sequestrant is a graft acrylic acid methyl esters on starch; obtain with quadrol generation amidate action again; it has a plurality of amino and acyl group; can with heavy metal ion form inner complex and precipitation with reach the purpose of purifying waste water (starch graft acrylic acid methyl esters and quadrol synthetic macromolecule sequestrant. Hu Chunhong etc. applied chemistry; in June, 2007,716～719 pages of the 24th the 6th phases of volume).But the ability of the disclosed heavy metal chelant chelating of this article heavy metal ion is still waiting to improve.

Summary of the invention

The technical problem to be solved in the present invention is further to improve the ability of the heavy metal chelant processing metallic wastewater of starch-containing skeleton structure.

The technical scheme that the present invention addresses the above problem is:

The graft copolymer of a kind of starch and N hydroxymethyl acrylamide, the main chain of this graft copolymer are starch, and side chain is poly-N hydroxymethyl acrylamide, the part of hydroxyl on the side chain by amination be amino or-NH-(C ₂H ₄NH) _n-C ₂H ₄-NH ₂, n=0～3; Percentage of grafting is 15～82%, and nitrogen content is 1～20%.

Percentage of grafting of the present invention is meant the mass percentage content of side chain in graft copolymer, and nitrogen content is the mass percentage content of nitrogen element in graft copolymer.

The preparation method of graft copolymer of the present invention, this method is made up of following steps: get starch, add mixing in 5～15 times of water; Feed nitrogen, the N hydroxymethyl acrylamide that the initiator of adding starch quality 0.3～5% and starch quality are 0.2～5 times is warming up to 30～70 ℃ of reaction 1～10h, gets starch-grafted N hydroxymethyl acrylamide multipolymer; Add the amination reagent of 5～30 times of gained multipolymer butt quality, stir, 95 ℃ of following condensing reflux 6～36h obtain white jelly, separate out, wash with dehydrated alcohol, and 45～85 ℃ of following vacuum-dryings get final product;

In the above-mentioned steps, described amination reagent is hydrazine hydrate, quadrol, diethylenetriamine, triethylene tetramine or tetraethylene pentamine; Described initiator is ammonium persulphate, potassium permanganate or ceric ammonium nitrate.

Preparing the used starch of multipolymer of the present invention can be cheap raw materials such as tapioca (flour), yam starch, W-Gum.

Multipolymer of the present invention can be used as metal traps and is used to handle electroplating wastewater.When multipolymer of the present invention is dissolved in electroplating wastewater, sequestering action takes place rapidly in functional group in the molecule and metal ion, generate insoluble product, the reticulated structure of himself can make the precipitation rapid flocculation sink again simultaneously, reach the purpose of removing metal ion in the waste water, the clearance of heavy metal ion is up to more than 99%.

Embodiment

Preparation example

The percentage of grafting of following example and nitrogen content are all measured as follows:

The measuring method of nitrogen content: adopt Kjeldahl determination, the nitrogen content in the working sample, calculation formula is as follows:

Nitrogen content %=[(V-V ₀) N/W] * 0.014 * 100

In the formula: V-consumes the milliliter number of HCl, mL;

V ₀The milliliter number mL of the HCl that-blank assay consumes;

The equivalent concentration of N-HCl

The W-sample weight, g.

The measuring method of percentage of grafting: employing gravimetric determination percentage of grafting (G, %).Dried thick product is wrapped with filter paper, placed the extracting of 250ml Soxhlet extractor to remove homopolymer, washing, suction filtration vacuum-drying get pure graft copolymer to constant weight.

Calculation formula is as follows:

$G=\frac{m_G-m_S}{m_G}\×100\%$

In the formula: m _S---the quality of reaction starch, g;

m _G---the quality of graft copolymer, g.

Example 1

Get tapioca (flour) 5g and distilled water 50mL and add in the 250mL there-necked flask, feed nitrogen, add 0.05g potassium permanganate and 10gN-n-methylolacrylamide, be warming up to 55 ℃ of reaction 4h, get starch-grafted N hydroxymethyl acrylamide multipolymer.Get multipolymer 2g (butt), add tetraethylene pentamine 30mL, stir, 95 ℃ of following condensing reflux 14h obtain white gluey product, separate out and washed product 50 ℃ of following vacuum-dryings with dehydrated alcohol.Record, percentage of grafting (G) is 65.33%, and nitrogen content (N) is 10.8%.

Example 2

Get yam starch 10g and distilled water 50mL and add in the 250mL there-necked flask, feed nitrogen, add 0.03g ammonium persulphate and 3gN-n-methylolacrylamide, be warming up to 55 ℃ of reaction 4h, get starch-grafted N hydroxymethyl acrylamide multipolymer.Get multipolymer 2g (butt), add hydrazine hydrate 15mL, stir, 95 ℃ of following condensing reflux 6h obtain white gluey product, separate out and washed product 50 ℃ of following vacuum-dryings with dehydrated alcohol.Record, percentage of grafting (G) is 19.67%, and nitrogen content (N) is 1.22%.

Example 3

Extracting corn starch 5g and distilled water 80mL add in the 250mL there-necked flask, feed nitrogen, add 0.12g ceric ammonium nitrate and 25gN-n-methylolacrylamide, are warming up to 65 ℃ of reaction 8h, get starch-grafted N hydroxymethyl acrylamide multipolymer.Get multipolymer 2g (butt), add diethylenetriamine 50mL, stir, 95 ℃ of following condensing reflux 36h obtain white gluey product, separate out and washed product 50 ℃ of following vacuum-dryings with dehydrated alcohol.Record, percentage of grafting (G) is 81.53%, and nitrogen content (N) is 19.68%.

The effect example

Example 4

Take by weighing example 1 gained final copolymer product 10mg, join and contain Ag ⁺The ion starting point concentration is in the 30mL electroplating wastewater of 100ppm, records Ag with atomic absorption analyzer behind the stirring 30min under the room temperature ⁺Ionic concn is 0.10ppm, Ag ⁺The ion remaval rate is near 99%.Difference by the forward and backward thermal weight loss of multipolymer absorption metal is calculated chelating Ag ²⁺Amount is 2.93mmolg ^-1

Example 5

Take by weighing example 1 gained final copolymer product 10mg, join and contain Pb ²⁺The ion starting point concentration is in the 30mL electroplating wastewater of 100ppm, records Pb with atomic absorption analyzer behind the stirring 30min under the room temperature ²⁺Ionic concn is 0.08ppm, Pb ²⁺Clearance is near 100%.Difference by the forward and backward thermal weight loss of chelating starch absorption metal is calculated chelating pb ²⁺Amount is 1.83mmolg ^-1

Comparative Examples:

Getting the starch-grafted methyl acrylate of 1g places logical N2 gas and has agitator and the there-necked flask of prolong, add acetone 25mL, stir, be heated to 55 ℃ with its dissolving with water-bath, add 0.01g KOH then, after stirring 2min, add the 15mL quadrol, with warming-in-water to 95 ℃, in 60 ℃ of loft drier, dry by the fire 24h behind the reaction 6h, be neutrality substantially with distillation washed several times with water to washing lotion then, with the washing after solid in 60 ℃ of dry 24h, obtain the aminating starch graft acrylic acid methyl terpolymer of quadrol (starch graft acrylic acid methyl esters and quadrol synthetic macromolecule sequestrant. Hu Chunhong etc. applied chemistry, in June, 2007, the 24th volume 716～719 pages of the 6th phases).

Take by weighing the aminating starch graft acrylic acid methyl terpolymer of above-mentioned quadrol 10mg, join Cu ²⁺The ion starting point concentration is in the 30mL electroplating wastewater of 100ppm, stirs 45min post-absorption analyser under the room temperature and records Cu ²⁺Ionic concn is 0.23ppm, and clearance is near 77%.

Take by weighing the aminating starch graft acrylic acid methyl terpolymer of above-mentioned quadrol 10mg, the 30mL that joins starting point concentration and be 100ppm contains Ag ⁺In the ion plating waste water, record Ag with atomic absorption analyzer behind the stirring 30min under the room temperature ⁺Ionic concn is 0.26ppm, and clearance is near 74%.

Claims (2)

1. the graft copolymer of starch and N hydroxymethyl acrylamide, the main chain of this graft copolymer is a starch, side chain is poly-N hydroxymethyl acrylamide, the part of hydroxyl on the side chain by amination be amino or-NH-(C ₂H ₄NH) _n-C ₂H ₄-NH ₂, n=0～3; Percentage of grafting is 15～82%, and nitrogen content is 1～20%.

2. the preparation method of the described graft copolymer of claim 1, this method is made up of following steps:

Get starch, add mixing in 5～15 times of water; Feed nitrogen, the N hydroxymethyl acrylamide that the initiator of adding starch quality 0.3～5% and starch quality are 0.2～5 times is warming up to 30～70 ℃ of reaction 1～10h, gets starch-grafted N hydroxymethyl acrylamide multipolymer; Add the amination reagent of 5～30 times of gained multipolymer butt quality, stir, 95 ℃ of following condensing reflux 6～36h obtain white jelly, separate out, wash with dehydrated alcohol, and 45～85 ℃ of following vacuum-dryings get final product;

In the above-mentioned steps, described amination reagent is hydrazine hydrate, quadrol, diethylenetriamine, triethylene tetramine or tetraethylene pentamine; Described initiator is ammonium persulphate, potassium permanganate or ceric ammonium nitrate.