CN111335022A - Bagasse-based heavy metal passivator preparation method, product and application - Google Patents

Abstract

The invention provides a preparation method, product and application of a bagasse-based heavy metal passivator. The air-dried cane pith is treated with a mixed solution of glacial acetic acid and hydrogen peroxide, then oxidized with sodium periodate, and epoxidized with epichlorohydrin. , and then react with triethylenetetramine and hyperbranched polyamine derivatives to obtain aminated modified sugarcane pith fiber, thereby improving the adsorption capacity of bagasse to heavy metals, which can be used for the adsorption and separation of heavy metals in heavy metal aqueous solutions.

Description

A kind of bagasse-based heavy metal passivator preparation method, product and application

technical field

The invention belongs to the field of heavy metal pollution control, and particularly relates to a preparation method, product and application of a bagasse-based heavy metal passivator.

Background technique

The main components of bagasse are lignin, cellulose and hemicellulose, of which cellulose accounts for the majority and contains a large number of active groups of hydroxyl groups. Cellulose is a polysaccharide widely distributed and abundant in nature, mainly distributed in annual or perennial plants, including wood, grass, ferns, etc., and is the main component of cell walls. The use of cellulose is also very extensive, among which the cellulose used in the textile and paper industries reaches 8 million tons per year. The separated and purified cellulose can be used to produce rayon, ester derivatives such as nitrocellulose and cellulose acetate, and ether derivatives such as methylcellulose, ethylcellulose, and carboxymethylcellulose, which are used in plastics, explosives, Electrician and scientific research equipment, etc. Chinese patent CN108993434A discloses a preparation method of a cane pith cellulose-based heavy metal ion adsorbent; Chinese patent CN108452774 discloses a heavy metal adsorption material prepared by biologically converting bagasse and its application. Due to the special chemical structure and stable physical properties of cellulose, cellulose-based adsorbents have become a research hotspot.

Heavy metal elements are widely present on the earth's surface and are distributed in the lithosphere, hydrosphere, atmosphere and biosphere. However, due to the increasing activities of human mining, smelting, processing and commercial manufacturing of heavy metals, many heavy metals such as lead and cadmium are caused. , cobalt, etc. into the atmosphere, water, soil, causing serious environmental pollution. And heavy metals existing in various chemical states will persist, accumulate and migrate after entering the environment or ecosystem, seriously threatening the survival of humans and other animals and plants. Heavy metal pollution is one of the most intractable water pollutions in the world. Finding cheap and effective heavy metal treatment methods is the top priority for environmental protection and ecological, scientific and sustainable development.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides a preparation method, product and application of a bagasse-based heavy metal passivator. A bagasse-based heavy metal passivator is prepared by utilizing the rich cellulose components in the agricultural waste bagasse, and used for the adsorption and removal of heavy metals in heavy metal sewage, and the bagasse-based heavy metal passivator obtained by the bagasse modification method of the present invention is processed The adsorption capacity of heavy metals has been greatly improved, and the effective and rational utilization of resources has been realized.

One of the technical solutions of the present invention, a method for preparing a bagasse-based heavy metal passivator, comprises the following steps:

(1) bagasse is air-dried, the fiber part is separated by the alkaline sulfite method, placed in the mixed solution of glacial acetic acid and hydrogen peroxide and soaked, washed with distilled water, and pulverized to obtain pith fiber, sealed for subsequent use after air-drying;

(2) get the cane pith fiber prepared in step (1) and add sodium periodate solution, adjust the pH value to be 2-4, shake the reaction, filter after the reaction is completed, rinse with distilled water until no iodine exists, filter and dry to obtain the oxidized fiber;

(3) the oxidized fiber prepared in step (2) is added with alkali solution, epichlorohydrin and absolute ethanol, after heating reaction, washed with water to neutrality, washed with ethanol, and dried to obtain epoxidized fiber;

(4) take the epoxidized fiber prepared in step (3), add the mixture of triethylenetetramine and triethylenetetramine hyperbranched polyamine derivative, alkaline solution, formaldehyde solution, water, filter after completion of the reaction, wash with water, ethanol Wash and dry to obtain a bagasse-based heavy metal passivator.

Preferably, in the step (1), the volume mixing ratio of glacial acetic acid and hydrogen peroxide in the mixed solution of glacial acetic acid and hydrogen peroxide is 1:1, the soaking temperature is 90-100°C, the soaking time is 1-4h, and the air-drying is performed. After crushing into 40-60 mesh, sugarcane pith fibers are obtained and sealed for use;

Preferably, in the step (2), the concentration of the sodium periodate solution is 0.4-0.6 mol/L, the reaction temperature is 35-45 °C, and the reaction is carried out in the dark, the reaction time is 2-4 h, and the drying temperature is 80 °C; If the temperature is too high, the content of aldehyde groups obtained by oxidation will decrease, and the reactivity of oxidized fibers will decrease.

Preferably, in the step (3), the alkali solution is sodium hydroxide with a mass fraction of 8%, and the addition ratio of oxidized fiber, alkali solution, epichlorohydrin and absolute ethanol is 1g:50mL:2-10mL: 5mL, reaction temperature 50-90℃, reaction time 1-2h, drying temperature 70℃;

Preferably, in the step (4), the mass mixing ratio of the mixture of triethylenetetramine and the triethylenetetramine hyperbranched polyamine derivative is 1:3-4, and the added amount is 30-150kg/kg epoxidation Fiber, the amount of alkali solution, formaldehyde solution and water added per 1kg of epoxidized fiber is 30-40L, 5-10L and 50-60L respectively, the reaction temperature is not higher than 60℃, the reaction time is 3h, and the drying temperature is 70℃;

The second technical solution of the present invention is the bagasse-based heavy metal passivator prepared by the above-mentioned preparation method of the bagasse-based heavy metal passivator.

The third technical solution of the present invention is the application of the above-mentioned bagasse-based heavy metal passivator in adsorbing heavy metal ions in a water body.

Compared with the prior art, the present invention has the following beneficial effects:

Before fiber modification, the basic sulfite method is used to fully separate and extract the fiber part in bagasse, which helps the subsequent modification of bagasse fibers not be affected by other impurities, so that the modification of bagasse fibers in the later stage is not affected. The process went smoothly. The bagasse treated by the alkaline sulfite method still contains lignin and hemicellulose which affect the fiber structure and exposed area of bagasse. Therefore, before the modification, it is necessary to use the mixed solution of glacial acetic acid and hydrogen peroxide to fully remove the residual lignin and hemicellulose between the fibers, so as to obtain Pure cane pith fibers.

Add sodium periodate solution to the cane pulp fibers obtained after the above treatment, and react in the dark for 2-4 hours at pH 2-4, 35-45 °C, and some hydroxyl groups will be selectively oxidized to aldehydes during the process. The light-proof reaction can avoid the decomposition of sodium periodate in the presence of light. After the reaction is completed, after the fiber is oxidized by sodium periodate, it is reduced to iodide ions by itself. Therefore, it is necessary to wash the reaction product with distilled water several times to fully remove the Iodine, dried to obtain activated oxidized cane pith fibers.

The oxidized cane pulp fiber oxidized by sodium periodate is reacted with epichlorohydrin in the presence of sodium hydroxide and ethanol, and the unoxidized hydroxyl group in the oxidized cane pulp fiber is in the presence of sodium hydroxide. Under natural conditions, the elimination reaction occurs with epichlorohydrin, and the epoxy group is grafted to the fiber to obtain epoxidized fiber, and ethanol plays the role of dispersing epichlorohydrin.

The epoxidized fiber is further reacted with a mixture of triethylenetetramine and triethylenetetramine hyperbranched polyamine derivatives in the presence of an alkaline solution and a formaldehyde solution, and the epoxy group is ring-opened with triethylene under alkaline conditions. Tetraamine and hyperbranched polyamine derivatives undergo a grafting reaction. At the same time, in the presence of formaldehyde, the aldehyde groups present in cellulose undergo Mannich reaction, and the hyperbranched amine derivatives can also be cross-linked and fixed on the fiber. surface to obtain enamined fibers. The obtained enamidated fibers have abundant amine groups with metal ion chelation, and the highly branched polyamine derivatives increase the charge density, so that the adsorption performance when used for heavy metal adsorption can be significantly improved.

In the present invention, part of the hydroxyl groups are converted into active aldehyde groups by oxidation, the remaining hydroxyl groups are grafted with active epoxy groups by epoxidation, and then the amino functional groups with adsorption and chelation are converted by amination reaction. Introduced into cane pith fibers, thereby greatly improving the adsorption properties of cane pith fibers. The invention uses waste crop bagasse as raw material, and after a series of modification treatments, the rich cellulose components can be fully utilized, the adsorption capacity is significantly improved, and the maximum utilization of waste resources is realized.

Description of drawings

Figure 1 shows the grafted modified cane pith fiber prepared in Example 1.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail, which detailed description should not be construed as a limitation of the invention, but rather as a more detailed description of certain aspects, features, and embodiments of the invention.

It should be understood that the terms described in the present invention are only used to describe particular embodiments, and are not used to limit the present invention.

Additionally, for numerical ranges in the present disclosure, it should be understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated value or intervening value in that stated range is also encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention relates. Although only the preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference for the purpose of disclosing and describing the methods and/or materials in connection with which the documents are referred. In the event of conflict with any incorporated document, the content of this specification controls.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present invention without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the present invention. The description and examples of the present invention are exemplary only.

Example 1

(1) The air-dried bagasse is separated from the fiber by the alkaline sulfite method and placed in a mixed solution of glacial acetic acid and hydrogen peroxide with a volume ratio of 1:1 for 2 hours at 100 °C to remove residual lignin and hemifibers Then, washed with distilled water, and air-dried to obtain cane pith fibers, which were pulverized with a plant-like pulverizer, and 40-60 mesh was taken and placed in a sealed bag for later use.

(2) Take 5 g of the cane pith fiber prepared in step (1) and place it in a beaker, add 0.4 mol/l sodium periodate at room temperature, adjust the pH to 3, and place it in a temperature-controlled water bath shaker at 40°C to avoid Photoreaction for 2h, clear with distilled water for several times, and use sodium thiosulfate to identify the absence of iodine (drop a drop of filtrate on starch potassium iodide test paper, then add dilute sulfuric acid and modified sugarcane pith fiber heavy metal adsorption material solution, no color change), The oxidized fibers were obtained by filtration, dried at 80°C, and used for later use.

(3) get the oxidized fiber obtained in 2g step (2) and pack in the there-necked flask with stirrer and thermometer, add 100ml 8% sodium hydroxide, 10ml epichlorohydrin, 10ml dehydrated alcohol, react at 80°C 1h, washed with water until neutral, washed with ethanol three times, and dried at 70°C to obtain epoxidized fibers.

(4) get the epoxidized fiber that 3g step (3) makes in there-necked flask, add the mixture of 90g triethylenetetramine and its derived hyperbranched polyamine (triethylenetetramine and its derived hyperbranched polyamine The mass mixing ratio is 1:3), 90ml of sodium hydroxide solution, 15ml of formaldehyde solution, 150ml of water, reacted at 50°C for 3h, filtered, washed with water, washed with ethanol, and dried at 70°C to obtain a bagasse-based heavy metal passivator.

Example 2

The same as Example 1, the difference is that in step (2), the concentration of sodium periodate is 0.6 mol/l, the pH is adjusted to 4, and the reaction is performed in a temperature-controlled water bath shaker at 35°C for 3 h in the dark; step (3) The amount of epichlorohydrin added in the middle is 15ml, and the reaction is carried out at 60 ° C for 2h; in step (4), the mixture of triethylenetetramine and its derived hyperbranched polyamine (the mass mixture of triethylenetetramine and its derived hyperbranched polyamine) The ratio of 1:3) was added in an amount of 100 g.

Example 3

Same as Example 1, the difference is that step (1) is not treated by soaking in a mixed solution of glacial acetic acid hydrogen peroxide with a volume ratio of 1:1 to remove residual lignin and hemicellulose.

Example 4

The same as in Example 2, the difference is that in step (4), the reaction time is 70° C. for 2 h.

Example 5

Same as Embodiment 2, the difference is that step (2) is omitted.

Example 6

Same as Embodiment 2, the difference is that step (3) is omitted.

Example 7

Same as Embodiment 2, the difference is that step (4) is omitted.

Effect verification

Get the bagasse-based heavy metal passivator prepared in Examples 1-7, and the sugarcane pith fibers prepared in the step (1) of Example 1, respectively, and place them in a Cu(II) metal solution with a concentration of 50 mg/L, and the pH is 5.5. At 30°C, the adsorption verification of copper ions was carried out, and the verification results are shown in Table 1;

Table 1

Adsorption saturation time, min Maximum adsorption capacity, mg/g Example 1 30 273 Example 2 40 289 Example 3 35 246 Example 4 30 225 Example 5 30 234 Example 6 30 219 Example 7 25 157 Cane pith fibers 60 65

The present invention has been described above with reference to the preferred embodiments, which are merely exemplary and serve an illustrative purpose. It should be pointed out that, without departing from the principle of the present invention, several replacements and improvements can be made, and these should all be included in the protection scope of the present invention.

Claims (7)

1. a bagasse-based heavy metal passivator preparation method, is characterized in that, comprises the following steps: (1) bagasse is air-dried, and the fiber part is separated by the alkaline sulfite method, and is placed in the mixed solution of glacial acetic acid and hydrogen peroxide to soak, washed with distilled water, and pulverized to obtain pith fiber after air-drying, and sealed for subsequent use; (2) get the cane pith fiber prepared in step (1) and add sodium periodate solution, adjust the pH value to be 2-4, shake the reaction, filter after the reaction is completed, rinse with distilled water until no iodine exists, filter and dry to obtain the oxidized fiber; (3) the oxidized fiber prepared in step (2) is added with alkali solution, epichlorohydrin and absolute ethanol, after heating reaction, washed with water to neutrality, washed with ethanol, and dried to obtain epoxidized fiber; (4) take the epoxidized fiber prepared in step (3), add the mixture of triethylenetetramine and triethylenetetramine hyperbranched polyamine derivative, alkaline solution, formaldehyde solution, water, filter after completion of the reaction, wash with water, ethanol Wash and dry to obtain a bagasse-based heavy metal passivator. 2. bagasse-based heavy metal passivator preparation method according to claim 1, is characterized in that, in described step (1), in the mixed solution of glacial acetic acid and hydrogen peroxide, the volume mixing ratio of glacial acetic acid and hydrogen peroxide It is 1:1, soaking temperature is 90-100 ℃, soaking time is 1-4h, air-dried and crushed into 40-60 mesh, and cane pith fiber is obtained and sealed for use. 3. bagasse-based heavy metal passivator preparation method according to claim 1, is characterized in that, in described step (2), sodium periodate solution concentration is 0.4-0.6mol/L, and reaction temperature is 35-45 ℃, the reaction was performed in the dark, the reaction time was 2-4 h, and the drying temperature was 80 ℃. 4. bagasse-based heavy metal passivator preparation method according to claim 1, is characterized in that, in described step (3), alkali solution is the sodium hydroxide that mass fraction is 8%, oxidized fiber, alkali solution, ring The addition ratio of oxychloropropane and absolute ethanol is 1g:50ml:5-10ml:5ml, the reaction temperature is 50-90°C, the reaction time is 1-2h, and the drying temperature is 70°C. 5. bagasse-based heavy metal deactivator preparation method according to claim 1, is characterized in that, in described step (4), the quality of the mixture of triethylenetetramine and triethylenetetramine hyperbranched polyamine derivative mixes The ratio is 1:3-4, the added amount is 30-150kg/kg epoxidized fiber, and the amount of alkali solution, formaldehyde solution and water added to each 1kg of epoxidized fiber is 30-40L, 5-10L and 50-60L respectively , the reaction temperature is not higher than 60 ℃, the reaction time is 3h, and the drying temperature is 70 ℃. 6. A bagasse-based heavy metal passivator prepared by the method for preparing a bagasse-based heavy metal passivator according to any one of claims 1-5. 7. a kind of application of bagasse-based heavy metal passivator according to claim 6 in adsorbing heavy metal ions in water body.

Images