Modified cellulose adsorbent (3)

a.
Acrylonitrile as monomer

I.
Method 1: Using cotton as the raw material, the viscose liquid is developed through the processes of alkalization, aging, yellowing and dissolution, and then the hot sol phase inversion method is used to uniformly disperse the viscose in the transformer oil to obtain the particle size It is 0.
8～1.
2mm spherical cellulose beads, and using it as the matrix, under the action of the initiator, it is grafted and copolymerized with acrylonitrile monomer, and then through crosslinking, saponification and esterification reactions, two new types of Spherical cellulose metal adsorbents SCAM-1 and SCAM-2
.

The specific preparation process is as follows
.

i.
Preparation of viscose Weigh 20.
0g cotton (moisture content 10%), after the first immersion in 18% NaOH solution at 50℃, press out the excess lye, and at room temperature (20～25℃) Perform the second immersion in 12% NaOH solution, then suction filter and squeeze the alkali cellulose to 50.
0g, smash and age at room temperature for 48h, add a certain amount of CS ₂ in a certain proportion , shake for 2.
5h, and then add 150mL 4.
0% NaOH solution and calculated amount of surfactant are dissolved to
prepare viscose
.

ii.

iii.
Preparation of SCAM-1 adsorbent grafting reaction: Add 60.
0g spherical cellulose beads (water content of 75.
3%) and 90mL water into a three-necked flask equipped with a stirrer, reflux condenser and thermometer, and stir for 10min at room temperature Then add 30mL 1.
2% oxidant aqueous solution, continue to stir for 5min, then add the calculated amount of acrylonitrile (the molar ratio of acrylonitrile to cellulose is 2.
4:1), after reacting for 1.
0h, filter, wash and dry to obtain cyanoethyl Cellulose beads
.

Cross-linking and saponification reaction: Add 20.
0g of cyanoethyl cellulose beads (water content of 30.
0%) and 40mL of water into a three-necked flask equipped with a stirrer, dropping funnel, thermometer and reflux condenser, and then add A certain amount of sodium chloride and epichlorohydrin , stir
.

iv.
Preparation of SCAM-2 adsorbent crosslinking reaction: Add 60.
0g spherical cellulose beads (water content of 75.
3%) into a three-necked flask equipped with a stirrer, reflux condenser and thermometer, and add a certain amount of chlorine Sodium sulfide and 120mL NaOH aqueous solution of a certain concentration, stirred at room temperature for 20 minutes, then add epichlorohydrin and continue to stir and react for 1.
0h, warm up to 75℃ and react for 1.
0h, then cool and filter, recover the lye, then wash, filter, and dry , That is, cross-linked cellulose beads
.

II.
Method 2: Using cerium ammonium nitrate as the initiator, grafting acrylonitrile on the cellulose, saponifying the copolymer and then amidoximation to prepare a new type of cellulose chelate containing amidoxime groups and carboxyl groups Adsorbent (AOSC)
.

The specific preparation process is as follows
.

i.
Preparation of cellulose-acrylonitrile graft copolymer (ANC).
6g (air-dried mass) horsetail bleached kraft pulp cellulose soaked in water for 24h was put into a three-necked flask with a stirrer and placed in a 50℃ constant temperature water bath.
After stirring with a certain amount of acidified cerium ammonium nitrate under N ₂ atmosphere for 15 minutes, add 120 mL of corresponding concentration of acrylonitrile to keep the reaction for a certain period of time, then take it out, rinse repeatedly with water until the effluent is clear, and dry to obtain ANC
.

ii.
Saponification of ANC Weigh 2g of ANC into a three-necked flask, add 80mL NaOH solution of a certain concentration, stir and react in a constant temperature water bath at 75℃ for 1h, then keep it warm and stand for 1h before taking it out, repeatedly washing with water and drying to obtain saponification Product
.

iii.
Preparation of semi-saponified amidoxime-based cellulose adsorbent Weigh 4g of the saponified product into a three-necked flask, add 70mL of methanol solution containing a certain concentration of hydroxylamine hydrochloride and 2g of anhydrous sodium carbonate , and react in a constant temperature water bath at 70°C Take it out after 1 hour of heat preservation and let stand for 2 hours, wash it repeatedly with water and dry it to obtain the semi-saponified amidoxime-based cellulose adsorbent (AOSC)
.

b.
Using acrylic acid as monomer

Using spherical cellulose beads as a matrix, under the action of an initiator, acrylic acid is used as a monomer for graft copolymerization to prepare a carboxylic acid (H) type cellulose adsorbent
.

First prepare a 40% sodium hydroxide aqueous solution and cool it to room temperature, and then gradually add acrylic acid diluted with the same amount of water into it
.

c.

Masson pine pulp (DP=360) is used as raw material, and the new solvent N-methylmorpholine-N-oxide (NMMO) is used as the solvent to dissolve cellulose to obtain a cellulose/NMMO solution, and then add a small amount according to a certain proportion Surfactant, mixed uniformly, dispersed in transformer oil, heated and solidified to obtain spherical cellulose, using NaHSO ₃ /K ₂ S ₂ O ₈ as the initiator, the 2-acrylamido-2-methylpropane Sulfonic acid (AMPS) is grafted onto the cross-linked spherical cellulose skeleton to prepare a spherical cellulose adsorbent

Add a certain volume ratio of the dispersed phase and the cellulose/NMMO/H ₂ O solution to a 250mL three-necked flask , and add an appropriate amount of dispersant, stir and disperse at a certain speed, and at the same time pass in nitrogen protection, and slowly heat it to a certain temperature Keep at constant temperature for 1.

Add 300g spherical cellulose beads (water content 74.

Add a certain quality of cross-linked spherical cellulose beads (with a moisture content of 61.

Related links: Modified cellulose adsorbent (2)