AU2021101487A4

AU2021101487A4 - Modified Biosorbent and Preparation Method Thereof

Info

Publication number: AU2021101487A4
Application number: AU2021101487A
Authority: AU
Inventors: Wangqiu Cai; Anhui Chen; Shanglong Chen; Chao Li; Enqi LIU
Original assignee: Xuzhou University of Technology
Current assignee: Xuzhou University of Technology
Priority date: 2021-03-23
Filing date: 2021-03-23
Publication date: 2021-05-13
Anticipated expiration: 2029-03-23

Abstract

The invention relates to a modified biosorbent and a preparation method thereof. The preparation method comprises the following steps of (1) swelling the dried and smashed Cordyceps militaris fungus chaff in sodium hydroxide aqueous solution for 4-6 h to obtain the pre-treated Cordyceps militaris fungus chaff; (2) adding the Cordyceps militaris fungus chaff after swelling pre-treatment into N,N-dimethylformamide dissolved with anhydride compounds, and let them react at 65-85°C for 2-4h to obtain an intermediate product I; (3) adding the intermediate product I into ethylenediamine aqueous solution, and at 80-90°C, the reaction is carried out for 1-3h while stirring to obtain an intermediate product II; (4) evenly mixing the intermediate product II with the sodium alginate solution, adding epichlorohydrin, performing reaction at 50-60°C for 30-60min, and then filtering to obtain a solid. Drying the solid to obtain the modified biosorbent. The modified biosorbent prepared by the invention has excellent adsorption effect on metal ions and dye molecules and can be reused.

Description

Modified Biosorbent and Preparation Method Thereof

TECHNICAL FIELD

The invention relates to the technical field of adsorption material preparation, in

particular to a modified biosorbent and a preparation method thereof.

BACKGROUND

Water pollution caused by various heavy metals in industrial wastewater is attracting

worldwide attention. Heavy metal ions are mainly released into the natural environment

through industrial wastewater from smelting, electrolysis and electroplating, urban

domestic wastewater and various mining wastewater. Because heavy metals cannot be

biodegraded or thermally degraded in nature, they may enter human body through food

chain and cause great harm to the human kidneys, lungs and other internal organs.

Traditional heavy metal wastewater treatment technologies mainly include chemical

precipitation, chemical oxidation and reduction, ion exchange, membrane technology,

electrochemical treatment, reverse osmosis and distillation, etc. However, these

traditional methods have the problem of secondary pollution, and especially when the

concentration of heavy metals in aqueous solution is low (< 100 mg/L), not only the

removal rate is low, but also the operation cost is high. Therefore, it has become a hot and

difficult point to find a cheap green sewage purification material with strong adsorption

capacity.

In addition, in the actual industrial production process, the dye uptake rate of fabric

dyeing is only 50%-98%, which leads to a large number of dyes in printing and dyeing

wastewater. On the one hand, it increases the difficulty of sewage treatment and causes great pollution to the environment; on the other hand, it also increases the cost of industrial production and causes unnecessary waste.

Biosorption method has attracted much attention because of its rich raw material sources,

low treatment cost, no toxicity, no secondary pollution and easy biodegradation. The

biosorption is a method that uses the chemical structure and composition characteristics

of certain organisms to adsorb chemical pollutants dissolved in water and remove

pollutants in aqueous solutions through solid-liquid two-phase separation. However, the

adsorption capacity of untreated biosorbent for pollutants is low, so it is difficult to be

directly applied to the removal of metal ions in industrial wastewater and the adsorption

and decolorization of dye residue.

SUMMARY

In view of the above-mentioned existing technology, the object of the present invention is

to provide a modified biosorbent and a preparation method thereof. The new modified

biosorbent prepared from Cordyceps militaris fungus chaff can be used for removing

metal ions in industrial wastewater and adsorbing and decolorizing dye residue.

In order to achieve the above purpose, the invention adopts the following technical

scheme.

The first aspect of the present invention provides a method for preparing the modified

biosorbent, which includes the following steps:

(1) swelling the dried and smashed Cordyceps militaris fungus chaff in sodium hydroxide

aqueous solution for 4-6 h and then taking out the Cordyceps militaris fungus chaff for

washing and drying to obtain pre-treated Cordyceps militaris fungus chaff;

(2) adding the Cordyceps militaris fungus chaff after swelling pre-treatment into N,N

dimethylformamide (DMF) dissolved with anhydride compounds and let them react at

-85°C for 2-4h. Then, an intermediate product I is obtained by suction filtration,

washing, and drying in sequence;

(3) adding the intermediate product I into ethylenediamine aqueous solution, and at 80-90

°C, a reaction is carried out for 1-3h while stirring. Then filtering, washing, and drying in

sequence to obtain an intermediate product II;

(4) evenly mixing the intermediate product II with the sodium alginate solution, adding

epichlorohydrin, performing reaction at 50-60°C for 30-60min, and then filtering to

obtain a solid. Drying the solid to obtain the modified biosorbent.

Preferably, in step (1), the mass concentration of the sodium hydroxide aqueous solution

is 20-30%; the temperature of the swelling pre-treatment is 60-80°C. The swelling pre

treatment of the Cordyceps militaris fungus chaff is conducive to further forming a loose

porous structure inside the Cordyceps militaris fungus chaff, facilitates subsequent

modification treatments, and effectively improves the adsorption performance of the

prepared biosorbent. The research of the present invention also finds that the

concentration of the sodium hydroxide aqueous solution for swelling pre-treatment and

the treatment temperature will affect the formation effect of the loose porous structure

inside the Cordyceps militaris fungus chaff. When the mass concentration of the sodium

hydroxide aqueous solution is 20-30% and the swelling pre-treatment temperature is 60

°C, the swelling pre-treatment has the best effect.

Preferably, in step (2), the mass ratio of the pre-treated Cordyceps militaris fungus chaff

to the anhydride compound is 1:4-6; the ratio of the added amount of Cordyceps militaris

fungus chaff after swelling pre-treatment to N, N-dimethylformamide is Ig: (20-30) ml.

Preferably, in step (2), the anhydride compound is pyromellitic dianhydride,

ethylenediaminetetraacetic dianhydride or succinic anhydride.

After the swelling pre-treatment, the Cordyceps militaris fungus chaff is further treated

by an anhydride compound, which can graft a large number of active functional groups

carboxyl groups onto the Cordyceps militaris fungus chaff, realizing the first

modification treatment of the Cordyceps militaris fungus chaff. The selection of

anhydride compounds and the modification treatment conditions, including the ratio of

the added amount of Cordyceps militaris fungus chaff to the anhydride compound,

reaction temperature and other conditions will affect the carboxylation modification

effect of Cordyceps militaris fungus chaff. The above reaction conditions of the invention

have the best carboxylation modification effect.

Preferably, in step (3), the mass concentration of the ethylenediamine aqueous solution is

-40%.

Preferably, in step (3), the ratio of the intermediate product I to the added amount of the

ethylenediamine aqueous solution is Ig: (10-14) ml.

After the first modification treatment, the Cordyceps militaris fungus chaff is reacted

with ethylenediamine to introduce a large number of amine groups, so as to realize the

second modification of the Cordyceps militaris fungus chaff, thereby it can utilize the

coordination of amine groups and different metal ions to achieve the adsorption and

separation of heavy metal ions.

Preferably, in step (4), the mass concentration of the sodium alginate solution is 3-6%.

Preferably, in step (4), the ratio of the added amount of the intermediate product II, the

sodium alginate solution and the epichlorohydrin is 1 g: (6-8) ml: (1-2) ml.

Finally, the Cordyceps militaris fungus chaff after the second modification treatment is

mixed with sodium alginate and epichlorohydrin, and then grafted and cross-linked,

which further improves the adsorption capacity of the prepared biosorbent.

The preparation process of the above-mentioned modified biosorbent is an organic whole,

that is, each step is complementary to each other, and there is a synergistic promoting

effect between the steps.

As the second aspect of the present invention, a modified biosorbent prepared by the

above method is provided.

As for the third aspect of the present invention, the application of the above-mentioned

modified biosorbent in removing heavy metal ions is provided.

The fourth aspect of the present invention provides the application of the above

mentioned modified biosorbent in the purification and treatment of dye wastewater.

The beneficial effects of the present invention are as follows.

(1) The main raw material of the modified biosorbent of the present invention is

Cordyceps militaris fungus chaff, which is rich in source and low in price; and compared

with other edible fungi fungus chaff, the Cordyceps militaris fungus chaff is also rich in

active groups on the surface of biological macromolecules such as cellulose and

hemicellulose, which is conducive to modification treatment. Moreover, the Cordyceps

militaris fungus chaff has more loose porous structure inside, which favours the

preparation of the biosorbent.

(2) The modified biosorbent prepared according to the present method has excellent

adsorption effect on metal ions and dye molecules, strong adsorption property and fast

adsorption speed. Besides, it can be reused, and has other advantages, such as low cost,

large adsorption capacity, stable performance and good regeneration performance.

DESCRIPTION OF THE INVENTION

It should be noted that the following detailed description is exemplary and is intended to

provide further explanation for this application. Unless otherwise specified, all technical

and scientific terms used herein have the same meanings as commonly understood by

general technical personnel in the technical field to which this application belongs.

In the present invention, Cordyceps militaris fungus chaff refers to the culture medium

residue after cultivating Cordyceps militaris with rice, silkworm chrysalis powder,

peptone, etc, as culture medium raw materials, and harvesting Cordyceps militaris

fruiting bodies.

Specifically, by mass percentage, the raw material composition of the culture medium for

cultivating Cordyceps militaris in the present invention is 82.3% of rice, 7.7% of

silkworm chrysalis powder, 3.8% of peptone, 5.4% of white sugar and 0.8%of K12PO4.

Cordyceps militaris is widely cultivated as a substitute of Cordyceps sinensis in various

places. Generally, lOg of dry material is required to produce 6g of dry fruiting bodies of

Cordyceps militaris. Therefore, the cultivation of Cordyceps militaris will produce a

large amount of fungus chaff, which has a wide range of sources and low cost.

In order to enable technicians in the field to understand the technical solutions of the

present application more clearly, the technical solutions of the present application will be

described in detail below in conjunction with specific embodiments.

The unspecified experimental materials used in the embodiments of the present invention

and the comparative embodiments are all conventional experimental materials in the field

and can be purchased through commercial channels.

The Cordyceps militaris fungus chaff used in following embodiments and comparative

embodiments is the residue of the culture medium after the Cordyceps militaris fruiting

bodies are harvested at the same place of origin and at the same time, and there is no

significant difference in the composition of its components.

Embodiment 1

(1) The Cordyceps militaris fungus chaff was dried to a constant weight at 80°C, then

crushed, and sieved with a 40-mesh sieve.

(2) Performing swelling pre-treatment at 70°C for 5h. Specifically, adding the dried and

crushed Cordyceps militaris fungus chaff in step (1) to the sodium hydroxide aqueous

solution with mass concentration of 25%. Further, the ratio of the added amount of

Cordyceps militaris fungus chaff to the sodium hydroxide aqueous solution was lg:10ml.

After the swelling pre-treatment, the Cordyceps militaris fungus chaff was taken out,

washed with deionized water to neutrality, and dried to obtain the pre-treated Cordyceps

militaris fungus chaff.

(3) The swelling pre-treated Cordyceps militaris fungus chaff was added into N, N

dimethylformamide (DMF) with succinic anhydride. The mass ratio of the swelling pre

treated Cordyceps militaris fungus chaff to succinic anhydride was 1:5, and the ratio to

N, N-dimethylformamide was lg:25ml. After reacting at 75C for 3h, the intermediate

product I was obtained by successively filtering, washing with deionized water until

neutral and drying.

(4) The intermediate I was added to 30% ethylenediamine aqueous solution, and the ratio

of intermediate I to ethylenediamine aqueous solution was Ig:12ml. The intermediate II

was obtained by stirring reaction for 2h at 85C, followed by filtration, washing with

deionized water to neutral and drying.

(5) The intermediate II was mixed with 4% sodium alginate solution, and epichlorohydrin

was added then. The ratio of intermediate II, sodium alginate solution and

epichlorohydrin was Ig: 7ml: 2ml. After 40min reaction at 50°C, solid was obtained by

filtration, and the modified biosorbent was obtained by drying the solid.

Embodiment 2

crushed, and sieved with a 40-mesh sieve.

(2) Performing swelling pre-treatment at 60°C for 6h. Specifically, adding the dried and

solution with mass concentration of 20%. Further, the ratio of the added amount of

Cordyceps militaris fungus chaff to the sodium hydroxide aqueous solution was lg:12ml.

militaris fungus chaff.

dimethylformamide (DMF) with succinic anhydride. The mass ratio of the swelling pre- treated Cordyceps militaris fungus chaff to succinic anhydride was 1:6, and the ratio to

N, N-dimethylformamide was lg:30ml. After reacting at 65C for 4h, the intermediate

neutral and drying.

(4) The intermediate I was added to 20% ethylenediamine aqueous solution, and the ratio

of intermediate I to ethylenediamine aqueous solution was Ig:14ml. The intermediate II

was obtained by stirring reaction for 1h at 90°C, followed by filtration, washing with

deionized water to neutral and drying.

(5) The intermediate II was mixed with 3% sodium alginate solution, and epichlorohydrin

was added then. The ratio of intermediate II, sodium alginate solution and

epichlorohydrin was Ig: 6ml: 2ml. After 30min reaction at 60°C, solid was obtained by

filtration, and the modified biosorbent was obtained by drying the solid.

Embodiment 3

crushed, and sieved with a 40-mesh sieve.

(2) Performing swelling pre-treatment at 80°C for 4h. Specifically, adding the dried and

solution with mass concentration of 30%. Further, the ratio of the added amount of

militaris fungus chaff.

treated Cordyceps militaris fungus chaff to succinic anhydride was 1:4, and the ratio to

N, N-dimethylformamide was lg:20ml. After reacting at 85C for 2h, the intermediate

neutral and drying.

(4) The intermediate I was added to 40% ethylenediamine aqueous solution, and the ratio

of intermediate I to ethylenediamine aqueous solution was lg:10ml. The intermediate II

was obtained by stirring reaction for 3h at 80°C, followed by filtration, washing with

deionized water to neutral and drying.

(5) The intermediate II was mixed with 6% sodium alginate solution, and epichlorohydrin

was added then. The ratio of intermediate II, sodium alginate solution and

epichlorohydrin was Ig: 8ml: 1ml. After 40min reaction at 50°C, solid was obtained by

filtration, and the modified biosorbent was obtained by drying the solid.

Comparative embodiment 1

The Cordyceps militaris fungus chaff in Embodiment 1 was replaced by

Auriculariaauricula fungus chaff, which is the culture medium residue after cultivating

and harvesting Auriculariaauricula with 20% of wheat-straw, 20% of straw, 30% of

sunflower stalk, 28% of cotton seed shell,1% of brown sugar and 1% of gypsum powder

as culture medium raw materials.

The preparation method was the same as above Embodiment 1, and the biosorbent A was

prepared.

Comparative embodiment 2

The Cordyceps militaris fungus chaff was dried to a constant weight at 105°C, then

crushed, and sieved with an 80-mesh sieve. The obtained Cordyceps militaris fungus

chaff powder was used as biosorbent B.

Comparative embodiment 3

crushed, and sieved with a 40-mesh sieve.

(2) The dried and crushed Cordyceps militaris fungus chaff was added into N, N

dimethylformamide (DMF) with succinic anhydride. The mass ratio of the Cordyceps

militaris fungus chaff to succinic anhydride was 1:5, and the ratio to N, N

dimethylformamide was lg:25ml. After reacting at 75 °C for 3h, biosorbent C was

obtained by successively suction filtration, washing with deionized water until neutral

and drying.

Comparative embodiment 4

crushed, and sieved with a 40-mesh sieve.

(2) The dried and crushed Cordyceps militaris fungus chaff was added to 30%

ethylenediamine aqueous solution, and the ratio of Cordyceps militaris fungus chaff to

ethylenediamine aqueous solution was Ig:12ml. Then biosorbent D was obtained by

stirring reaction for 2h at 85C, followed by filtration, washing with deionized water to

neutral and drying;

Experimental embodiment 1 Application of the biosorbent in adsorption of heavy metal

ions mg of each biosorbent prepared in the Embodiment 1 and Comparative embodiments

1-4 was respectively added into 150ml of heavy metal ion solution with certain

concentration. Making them adsorb heavy metal ions under stirring condition. After a

certain period of time, the adsorption capacity and efficiency of biosorbent were

measured and calculated.

Calculation formula of adsorption capacity is

Q(CO-CI)x V

Wherein, Q is the adsorption capacity in mg/g; Co is the concentration of simulated

solution at the initial time; Ct is the concentration of simulated solution at moment t; V is

the volume of simulated solution; m is the mass of biosorbent.

The calculation formula of adsorption efficiency is as follows:

CO -Ct X 100 CO

Wherein, Co is the concentration of simulated solution at the initial time; CT is the

concentration of simulated solution at moment t.

(1) Adsorption of Cu" at 25C for10min with pH 4 and initial concentration of 40mg/L.

The determination results of the adsorption capacity and adsorption efficiency of

biosorbents prepared in the Embodiment 1 and Comparative embodiments 1-4 are shown

in Table 1.

Table 1

Biosorbent Adsorption capacity (mg/g) Adsorption efficiency (%) Embodiment 1 287.1 95.7 Comparative embodiments 2 243.9 81.3 Comparative embodiments 3 177.9 59.3 Comparative embodiments 4 214.8 71.6

Comparative embodiments 5 195.4 65.1 2 (2) Adsorption of Hg at 25C for 10min with pH 4.5 and initial concentration of

mg/L.

in Table 2.

Table 2

Biosorbent Adsorption capacity (mg/g) Adsorption efficiency (%) Embodiment 1 281.5 93.8 Comparative embodiments 2 225.6 75.2 Comparative embodiments 3 176.4 58.8 Comparative embodiments 4 214.6 71.5 Comparative embodiments 5 182.0 60.7 Experimental embodiment 2 Application of biosorbent in adsorbing dye molecules

mg of each biosorbent prepared in the Embodiment 1 and Comparative embodiments

1-4 was respectively added into 150ml of dye solution with certain concentration. Making

them adsorb dye molecules for a certain period of time, and then the adsorption capacity

and efficiency of biosorbent were measured and calculated.

Calculation formula of adsorption capacity is

(CO- CI xV

the volume of simulated solution; m is the mass of biosorbent.

The calculation formula of adsorption efficiency is as follows:

CO - CI X0% CO

Wherein, Co is the concentration of simulated solution at the initial time; C1 is the

concentration of simulated solution at moment t.

(1) Adsorption of methylene blue at 50°C for 10min with pH 7.9 and initial concentration

of 30mg/L.

in Table 3.

Table 3

Biosorbent Adsorption capacity (mg/g) Adsorption efficiency(%) Embodiment 1 214.6 95.4 Comparative embodiments 2 178.1 79.2 Comparative embodiments 3 126.0 56.0 Comparative embodiments 4 138.0 61.3 Comparative embodiments 5 147.4 65.5 (2) Adsorption of methyl orange at 50°C for 8min with pH 8.2 and initial concentration

of 30mg/L.

in Table 4.

Table 4

Biosorbent Adsorption capacity (mg/g) Adsorption efficiency(%) Embodiment 1 218.2 97.0 Comparative embodiments 2 169.9 75.5 Comparative embodiments 3 113.8 50.6 Comparative embodiments 4 129.0 57.3 Comparative embodiments 5 126.3 56.1 It can be seen from Tables 1 to 4 that the modified biosorbent prepared by the present

invention has an excellent adsorption effect on metal ions and dye molecules, with strong

adsorption property and fast adsorption speed.

Experimental embodiment 3 Renewability test of the biosorbent

After using the modified biosorbent prepared in Embodiment 1 to adsorb heavy metal

ions or dyes, it was desorbed with 0.1% dilute hydrochloric acid solution. In the first 8

repeated uses, the adsorption capacity of the modified biosorbent did not change much. In

the 9th adsorption test, its adsorption capacity only dropped by 5%.

The experimental results indicate that the modified biosorbent prepared by the present

invention can be reused repeatedly and has strong regeneration ability.

The foregoing descriptions are only preferred embodiments of the application and are not

intended to limit the application. For technical personnel in the field, the application can

have various modifications and changes. Any modification, equivalent replacement,

improvement, etc. made within the spirit and principle of this application shall be

included in the protection scope of this application.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A preparation method of the modified biosorbent, characterized by including the

following steps:

aqueous solution for 4-6h and then taking out the Cordyceps militaris fungus chaff for

washing and drying to obtain pre-treated Cordyceps militaris fungus chaff;

washing, and drying in sequence;

sequence to obtain an intermediate product II;

obtain a solid. Drying the solid to obtain the modified biosorbent.

2. The preparation method of the modified biosorbent as stated in Claim 1, characterized

in that in step (1), the mass concentration of the sodium hydroxide aqueous solution is

-30%; the temperature of the swelling pre-treatment is 60-80°C.

3. The preparation method of the modified biosorbent as stated in Claim 1, characterized

in that in step (2), the mass ratio of the pre-treated Cordyceps militaris fungus chaff to the

anhydride compound is 1:4-6; the ratio of the added amount of Cordyceps militaris

4. The preparation method of the modified biosorbent as stated in Claim 1, characterized

in that in step (2), the anhydride compound is pyromellitic dianhydride,

ethylenediaminetetraacetic dianhydride or succinic anhydride.

5. The preparation method of the modified biosorbent as stated in Claim 1, characterized

in that in step (3), the mass concentration of the ethylenediamine aqueous solution is 20

%.

6. The preparation method of the modified biosorbent as stated in Claim 1 or 5,

characterized in that in step (3), the ratio of the intermediate product I to the added

amount of the ethylenediamine aqueous solution is Ig: (10-14) ml.

7. The preparation method of the modified biosorbent as stated in Claim 1, characterized

in that in step (4), the mass concentration of the sodium alginate solution is 3-6%.

sodium alginate solution and the epichlorohydrin is 1 g: (6-8) ml: (1-2) ml.

8. A modified biosorbent prepared by the method as stated in Claims 1-7 is provided.

9. An application of the modified biosorbent in Claim 8 in removing heavy metal ions is

provided.

10. An application of the modified biosorbent in Claim 8 in the purification and treatment

of dye wastewater.