Preparation method and application of hydroxyethyl cellulose-based composite material adsorbent

Abstract

The invention relates to the technical field of adsorption materials, in particular to a preparation method and application of a hydroxyethyl cellulose-based composite adsorbent, and the preparation method comprises the following steps: A, mixing melamine, p-xylylene dichloride, a catalyst and alkali in an organic solvent, and reacting to obtain a crude product for later use; b, cleaning and drying the crude product obtained in the step A with an organic solvent to obtain an intermediate material; c, dispersing the intermediate material in the step B and sodium hydroxide into a hydroxyethyl cellulose solution to obtain dispersion liquid; d, adding a cross-linking agent into the dispersion liquid in the step C for reaction, separating a product after the reaction, and cleaning and drying to obtain an adsorbent; the adsorbent is mainly used for adsorbing and removing low-concentration phenolic substances, the phenolic substances in the wastewater are removed through an adsorption means, and a technical means is provided for removing the phenolic substances. The scheme has the technical effects that the adsorption capacity is large, the removal effect is good, and the adsorption material can be repeatedly utilized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of adsorption materials, and in particular to a preparation method and application of a hydroxyethyl cellulose-based composite adsorbent. BACKGROUND

[0002] Phenolic substances are important raw materials in the fields of medicine and chemical industry. As the main component of wastewater, phenolic substances can cause serious pollution to soil through the penetration of water bodies. These phenolic substances can also easily accumulate in animals and plants in water areas, crops, and thus enter the biosphere, causing harm to human health. The oxidation-reduction treatment method, such as the classic Fenton method, cannot completely remove or oxidize phenolic substances into other toxic and harmful substances. SUMMARY

[0003] To solve the above technical problems, the embodiments of the present application provide a preparation method and application of a hydroxyethyl cellulose-based composite adsorbent.

[0004] To achieve the above-mentioned purposes, the embodiments of the present application adopt the following technical solutions: On the one hand, the present application provides a preparation method of a hydroxyethyl cellulose-based composite adsorbent, comprising the following steps: A. mixing melamine, p-dichlorobenzyl, a catalyst and a base in an organic solvent, and obtaining a crude product by reaction, for standby; B. cleaning and drying the crude product obtained in step A by an organic solvent to obtain an intermediate material; C. dispersing the intermediate material in step B and sodium hydroxide into a hydroxyethyl cellulose solution to obtain a dispersion liquid; D. adding a crosslinking agent to the dispersion liquid in step C to react, and separating, cleaning and drying the product after reaction to obtain an adsorbent.

[0005] In some embodiments, in step A, the molar ratio of melamine to p-dichlorobenzyl is 1:3-3:3.

[0006] In some embodiments, in step A, the amount of the catalyst and the base is 1-5% of the total mass of melamine and p-dichlorobenzyl.

[0007] In some embodiments, the catalyst is cuprous chloride, and the base is potassium carbonate.

[0008] In some embodiments, in step A, the reaction temperature is 130-160℃, and the reaction time is 10-20h.

[0009] In some embodiments, in step B, the organic solvent includes at least one of dichloromethane, tetrafluoro hydrogen furan and methanol.

[0010] In some embodiments, in step C, the mass fraction of the hydroxyethyl cellulose solution is 1-3%, the intermediate material accounts for 10-50 wt% of the total mass of the hydroxyethyl cellulose and the intermediate material, and the concentration of the sodium hydroxide in the hydroxyethyl cellulose solution is 6%.

[0011] In some embodiments, in step D, the amount of the crosslinking agent is 10-20% of the amount of the hydroxyethyl cellulose.

[0012] In some embodiments, the crosslinking agent is epichlorohydrin, the temperature of the reaction is 60-80 ℃, and the reaction time is 10-20 h.

[0013] In another aspect, the present application also provides a hydroxyethyl cellulose-based composite adsorbent prepared by the above preparation method.

[0014] In still another aspect, the present application also provides the use of a hydroxyethyl cellulose-based composite adsorbent prepared by the above preparation method in the adsorption and removal of phenols.

[0015] The main use of the adsorbent of the present application is to treat low-concentration (0-20 mg / L) phenol-containing wastewater. The adsorption capacity of the adsorbent for low-concentration phenol-containing wastewater (p-nitrophenol, m-nitrophenol, etc.) is 2.1 mg-3.2 mg / g. After repeated use for 8 times, the adsorption capacity still remains in this range, and the mass loss of the adsorbent is less than 15%.

[0016] The present application has the following advantages: (1) The present application obtains a porous powder material (intermediate material, referred to as PMF) with high specific surface area by crosslinking reaction of melamine and p-dichlorobenzene. After dispersing the PMF into a hydroxyethyl cellulose gel, the surface area of the obtained composite adsorbent (HGel / PMF) is between 60-100 m 2 / g.

[0017] (2) The adsorbent HGel / PMF prepared by the present application is obtained by dispersing the porous material PMF with high specific surface area into a gel material. The stability of the composite material can be improved through hydrogen bonding and etherification reaction between the PMF and the hydroxyethyl cellulose gel, which solves the problem of secondary pollution caused by the difficulty in recycling of the powder material after use, while fully ensuring the strong adsorption performance of the original PMF powder material.

[0018] (3) The adsorbent HGel / PMF synthesized by the present application contains a large amount of melamine rings in the dispersed phase PMF, and the large amount of nitrogen elements in the melamine rings can improve the enrichment capacity of the adsorbent for phenol-containing substances through hydrogen bonding and π-π interaction between aromatic rings.

[0019] The present application is to overcome the current adsorbent preparation process is complex, short service life, poor adsorption performance (especially for low concentration wastewater), and design, synthesis of a cross-linked hydroxyethyl cellulose as the matrix of the adsorbent, through the modification, to make full use of the toughness of cross-linked hydroxyethyl cellulose gel, and fully improve the adsorption performance and service life of the adsorbent. The adsorbent is mainly used for low concentration phenolic substances adsorption removal, which is removed by adsorption means for phenolic substances in wastewater, and provides a technical means for the removal of phenolic substances. It has the characteristics of large adsorption capacity and good removal effect, and the adsorption material can be repeatedly used for many times. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The adsorption of p-nitrophenol by the sample HGel / PMF-4 obtained in Example 4 is shown in the figure (a) cycle number; (b) residual percentage of the adsorbent after each cycle. DETAILED DESCRIPTION

[0021] The technical solutions in some embodiments of the present disclosure will be described clearly and completely in combination with the drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all. Based on the embodiments provided by the present disclosure, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present disclosure.

[0022] Example 1

[0023] (1) Take 1.26 g of melamine, 5.26 g of p-dichlorobenzene, 0.039 g of cuprous chloride, 0.039 g of potassium carbonate, and 1.50 mL of dimethyl sulfoxide, and react at 150℃ until the potassium carbonate disappears. Filter out the product, wash with dichloromethane, tetrahydrofuran, and methanol, and dry in a vacuum oven to obtain the adsorbent PMF-1.

[0024] (2) Take 6.0 g of sodium hydroxide and dissolve it in 94.0 g of water, add 1.50 g of hydroxyethyl cellulose, and stir until dissolved. Then add 0.50 g of PMF-1, disperse thoroughly, and then add 0.30 g of epichlorohydrin. After uniform dispersion, place the mixture in a 70℃ oven and react for 10 h. Finally, soak the gel product in deionized water, freeze-dry to obtain the adsorbent, and mark it as HGel / PMF-1.

[0025] Example 2

[0026] The same as Example 1, except that the PMF-1 in step (2) is 0.67 g, and the adsorbent is marked as HGel / PMF-2.

[0027] Example 3

[0028] Similar to Example 1, except that the PMF-1 in step (2) is 1.0 g and the adsorbent is denoted as HGel / PMF-3.

[0029] Example 4

[0030] Similar to Example 1, except that the PMF-1 in step (2) is 1.50 g and the adsorbent is denoted as HGel / PMF-4.

[0031] Figure 1 Figure (a) shows the adsorption experiment of p-nitrophenol by the adsorbent HGel / PMF-4 obtained in Example 4. In the first adsorption experiment, the adsorption removal rate was 80%. After 8 cycles of use, the adsorption rate dropped to 68%, a decrease of only 12%.

[0032] Figure 1 Figure (b) shows the percentage of adsorbent remaining in each cycle of Example 4. After 8 cycles, the percentage of remaining adsorbent was 85%, and the mass loss rate was no more than 15%.

[0033] Comparative Example 1 6.0 g of sodium hydroxide was dissolved in 94.0 g of water, and 1.50 g of hydroxyethyl cellulose was added. After thorough stirring and dissolution, 0.30 g of epichlorohydrin was added. The mixture was placed in an oven at 70 °C and reacted for 10 h. Finally, the obtained gel material was thoroughly soaked and washed with deionized water, and then freeze-dried to obtain cross-linked hydroxyethyl cellulose gel (HGel).

[0034] Comparative Example 2 (1) Weigh 1.26 g of melamine, 5.26 g of benzyl dichloroisocyanurate, 0.039 g of cuprous chloride, 0.039 g of potassium carbonate, and 1.50 mL of dimethyl sulfoxide. React at 150 °C until the potassium carbonate disappears. Filter out the product, wash with dichloromethane, tetrahydrofuran, and methanol, filter again, and dry in a vacuum oven to obtain adsorbent PMF-1.

[0035] Comparative Example 3 Similar to Comparative Example 2, except that in step (1) the amount of benzyl dichloroisocyanurate was 2.63 g, resulting in adsorbent PMF-2.

[0036] Comparative Example 4 (1) Weigh 1.26 g of melamine, 5.26 g of benzyl dichloroisocyanurate, 0.079 g of cuprous chloride, 0.039 g of potassium carbonate, and 1.50 mL of dimethyl sulfoxide. React at 150 °C until the potassium carbonate disappears. Filter the product, wash it with dichloromethane, tetrahydrofuran, and methanol, filter it under vacuum, and dry it in a vacuum oven to obtain the adsorbent PMF-3.

[0037] 0.10 g each of samples HGel / PMF-1, HGel / PMF-2, HGel / PMF-3, and HGel / PMF-4 prepared in Examples 1-4 and samples HGel, PMF-1, PMF-2, and PMF-3 obtained in Comparative Examples 1-4 were weighed and placed in 50 mL of 8.0 mg / L p-nitrophenol solution for adsorption experiments, and the adsorption effect was detected. The test results of the adsorption performance of p-nitrophenol on samples obtained in Examples 1-4 and Comparative Examples 1-4 are shown in Table 1: Table 1. Specific surface area and adsorption performance results of the adsorbents obtained in Examples 1-4 and Comparative Examples 1-4.

[0038] All samples were adsorbed in a 50 mL solution of 8.0 mg / L p-nitrophenol.

[0039] Analysis of the data from Examples 1-4 and Comparative Examples 1-4 shows that the specific surface area of ​​the materials obtained with a melamine / benzyl chloride ratio of 1 / 3 to 3 / 3 and a cuprous chloride usage of 1-5% (total mass of melamine and benzyl chloride) is 80-120 m². 2 These PMF materials exhibit adsorption capacities of 2.4–3.2 mg / g for low concentrations of p-nitrophenol (8.0 mg / L), with removal rates ranging from 60% to 80%. After dispersing the powder material into hydroxyethyl cellulose gel, the resulting HGel / PMF composite gel material has a specific surface area of ​​60–84 m² / g. 2 The specific surface area of ​​the adsorbent was lower than that of PMF powder material, but the adsorption capacity for p-nitrophenol was between 2.1 and 3.2 mg / g, and the removal rate was between 50% and 80%. The adsorption capacity and removal rate of the adsorbent in the examples were almost the same as those of the comparative HGel gel material and PMF powder material. This further illustrates that the composite gel strategy can effectively solve the problems of difficult recycling and environmental pollution after use of powder material adsorbents.

[0040] The above description of various embodiments and comparative examples of the present invention is merely exemplary and should not be construed as limiting the present invention. Those skilled in the art can modify the above embodiments and comparative examples within the scope of the present invention.

[0041] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0042] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a hydroxyethyl cellulose-based composite adsorbent, characterized in that, Includes the following steps: A. Melamine, benzyl chloride, catalyst and alkali are mixed in an organic solvent and reacted to obtain a crude product for later use; B. The crude product obtained in step A is washed with an organic solvent and dried to obtain the intermediate material; C. Disperse the intermediate material from step B and sodium hydroxide into a hydroxyethyl cellulose solution to obtain a dispersion; D. Add a crosslinking agent to the dispersion in step C and react. After the reaction, separate the product, wash and dry it to obtain the adsorbent.

2. The preparation method according to claim 1, characterized in that, In step A, the molar ratio of melamine to benzyl dichloroisocyanurate is 1:3 to 3:

3.

3. The preparation method according to claim 1, characterized in that, In step A, the amount of both the catalyst and the alkali used is 1 to 5% of the total mass of melamine and benzyl dichloroisocyanurate.

4. The preparation method according to claim 3, characterized in that, The catalyst is cuprous chloride, and the base is potassium carbonate.

5. The preparation method according to claim 1, characterized in that, In step A, the reaction temperature is 130~160℃ and the reaction time is 10~20 h.

6. The preparation method according to claim 1, characterized in that, In step B, the organic solvent includes at least one of dichloromethane, tetrafluorohydroran, and methanol.

7. The preparation method according to claim 1, characterized in that, In step C, the mass fraction of the hydroxyethyl cellulose solution is 1-3%, the intermediate material accounts for 10-50 wt% of the total mass of the hydroxyethyl cellulose and the intermediate material, and the concentration of sodium hydroxide in the hydroxyethyl cellulose solution is 6%.

8. The preparation method according to claim 1, characterized in that, In step D, the amount of crosslinking agent used is 10-20% of the amount of hydroxyethyl cellulose used.

9. The preparation method according to claim 8, characterized in that, The crosslinking agent is epichlorohydrin, the reaction temperature is 60~80 ℃, and the reaction time is 10~20 h.

10. The application of a hydroxyethyl cellulose-based composite adsorbent prepared by any one of claims 1 to 9 in the adsorption and removal of phenols.

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