Spherical schottky mineral-wood fiber composite adsorption material, and preparation method and application thereof

Abstract

The application discloses a spherical schillerization mineral-wood fiber composite adsorbing material and a preparation method and application thereof. The spherical schillerization mineral-wood fiber composite adsorbing material is prepared from schillerization minerals and bagasse wood fiber cellulose through an embedding method, and the problems of low adsorbing performance of a biomass adsorbing agent to Cr(VI) under an alkaline condition and easy loss of a schillerization mineral adsorbing agent are solved.

Description

Technical Field

[0001] This invention belongs to the field of adsorption materials technology, specifically relating to a spherical Scheres mineral-lignocellulose composite adsorption material, its preparation method, and its application. Background Technology

[0002] Hexavalent chromium (Cr(VI)) is a typical toxic and harmful heavy metal pollutant in water bodies, and its pollution control has always been a major concern. Currently, the main methods for removing Cr(VI) from water include chemical reduction precipitation, adsorption, and biological methods. Adsorption is the most suitable method for treating water bodies polluted with low to medium concentrations of Cr(VI) due to its rapid and effective nature and minimal secondary pollution. Among these methods, the use of low-cost lignocellulose biomass materials to adsorb heavy metal pollutants such as Cr(VI) from water has become a research hotspot in the adsorption field in recent years, known as bioadsorption. On the one hand, studies have reported that biomass and its modified bioadsorbent materials have good removal effects on Cr(VI) under acidic conditions, mainly because Cr(VI) is more easily reduced to Cr(III) under acidic conditions; however, as the solution pH increases to alkaline conditions, the adsorption removal effect gradually weakens. On the other hand, studies have found that Schönbach's mineral materials rich in sulfate and iron ions have good adsorption performance on Cr(VI) in water under slightly alkaline conditions. However, Schönbach's mineral is a powder material, which is easily lost in water as an adsorbent, making recycling difficult. Summary of the Invention

[0003] The purpose of this invention is to provide a spherical Scherstein mineral-lignocellulose composite adsorbent material, its preparation method, and its application. The above-mentioned spherical Scherstein mineral-lignocellulose composite adsorbent material is prepared by an encapsulation method, which improves the problems of low adsorption performance of biomass adsorbents for Cr(VI) under alkaline conditions and easy loss of Scherstein mineral adsorbents.

[0004] The technical solution of the present invention is as follows:

[0005] A method for preparing a spherical Scherstein mineral-lignocellulose composite adsorbent material includes the following steps:

[0006] (1) Sugarcane bagasse is washed, dried and crushed to obtain sugarcane bagasse powder. 1-Allyl-3-methylimidazolium chloride, N,N-dimethylformamide, sugarcane bagasse powder and NaHCO3 are mixed in a mass ratio of 10:8-12:0.5-0.7:0.05-0.07 and stirred continuously at 110℃ for 1h to obtain a sugarcane lignocellulose viscose solution in which all components are dissolved.

[0007] (2) Mix Schiele mineral with sugarcane lignocellulose viscose solution and stir continuously at 105-115℃ for 0.8-1.2h to obtain a composite solution. The mass ratio of Schiele mineral to sugarcane bagasse powder is 4-6:3.

[0008] (3) Add the composite solution dropwise to a 0.1 mol·L⁻¹ solution in a coagulation bath. -1 After being left to stand in an aqueous HCl solution for 3.4-4.5 hours, the material was washed and freeze-dried to obtain the above-mentioned spherical Schiele mineral-lignocellulose composite adsorbent material. The temperature of the coagulation bath was not greater than 40℃.

[0009] In some possible implementations, the preparation of Schiele minerals includes the following steps: slowly adding a 30 wt% H2O2 solution dropwise to Fe... 2+ Concentration of 2 g·L -1 The solution is prepared by stirring in a ferrous salt solution at room temperature for 24 hours, retaining the solids, and then freeze-drying. The volume ratio of H2O2 solution to ferrous solution is 1:160-240.

[0010] In some possible implementations, the ferrous salt is ferrous sulfate and / or ferrous sulfate heptahydrate.

[0011] In some possible implementations, the H2O2 solution is added at a rate of 1 drop every 2 minutes.

[0012] In some possible implementations, the drying temperature in step (1) is 55-60°C and the drying time is 24 hours.

[0013] In some possible implementations, the sugarcane bagasse powder has a particle size of less than 100 mesh, and the Schiele mineral has a particle size of less than 200 mesh.

[0014] A spherical Scheres mineral-lignocellulose composite adsorbent material is prepared by the above-described method.

[0015] An adsorbent comprising the above-mentioned spherical Schiele mineral-lignocellulose composite adsorbent material.

[0016] Application of the above-mentioned spherical Schiele mineral-lignocellulose composite adsorbent or the above-mentioned adsorbent in adsorbing Cr(VI) in water.

[0017] The present invention has at least the following beneficial effects:

[0018] The spherical Sch@LCB mineral-lignocellulose composite adsorbent material prepared by this invention is an ochre-yellow spherical material with a complete shape, uniform particle size, an average particle size of about 2 mm, and good mechanical strength. It exhibits good adsorption effect under slightly alkaline conditions, i.e., pH=8-9, and has good regeneration performance, showing potential for repeated use. Attached Figure Description

[0019] Figure 1 A schematic diagram of the preparation process of spherical Schiele mineral-lignocellulose composite adsorbent material (ScH@LCB);

[0020] Figure 2 Photograph of the appearance of the spherical Schiele mineral-lignocellulose composite adsorbent (ScH@LCB);

[0021] Figure 3 The adsorption performance of Sch@LCB under different pH conditions;

[0022] Figure 4 The adsorption performance of Sch@LCB under different dosage conditions;

[0023] Figure 5 Research on Sch@LCB regeneration adsorption;

[0024] Figure 6 The effect of coexisting ions on the adsorption of hexavalent chromium by Sch@LCB;

[0025] Figure 7 For the study of the stability of Sch@LCB adsorbent. Detailed Implementation

[0026] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0027] In the following embodiments, the water used can be one or more of distilled water, purified water, and drinking water; unless otherwise specified, the detection methods in the following embodiments are conventional detection methods; unless otherwise specified, the reagents in the following embodiments are all purchased from commercial channels. The Scheringer mineral in Example 1 is obtained by reacting ferrous sulfate heptahydrate with hydrogen peroxide. In other possible implementations, the Scheringer mineral can also be purchased directly from commercial channels.

[0028] In step (4) of Example 1, 0.1 mol·L -1 The HCl aqueous solution used as a coagulation bath has no proportional relationship with the composite solution; it only needs to be able to submerge the spherical Schiele mineral-lignocellulose composite adsorbent material.

[0029] Example 1

[0030] according to Figure 1 The preparation method of the spherical Schläss mineral-lignocellulose composite adsorbent (Sch@LCB) includes the following steps:

[0031] (1) Wash the sugarcane bagasse with tap water, then place it in an air drying oven and dry it at 60°C for 24 hours. After grinding it with a ball mill, pass it through a 100-mesh sieve to obtain sugarcane bagasse powder.

[0032] Weigh 10g of ionic liquid (1-allyl-3-methylimidazolium chloride) into a three-necked flask, and slowly add 10g of N,N-dimethylformamide (DMF), 0.6g of sugarcane bagasse, and 0.06g of NaHCO3. Stir continuously at 110℃ for 1h to obtain a sugarcane lignocellulose viscose solution in which all components are dissolved.

[0033] (2) Add 10g of FeSO4·7H2O to 1L of ultrapure water and stir with a magnetic stirrer until completely dissolved to obtain a ferrous salt solution. Then, add 5mL of 30wt% H2O2 solution dropwise to the ferrous salt solution at 1 drop every 2 minutes. Stir the mixture continuously at room temperature for 24 hours. Finally, separate the solid and liquid phases by vacuum filtration to obtain the solid product, which is Schöndorfite. Freeze-dry the Schöndorfite and collect the Schöndorfite powder that passes through a 200-mesh sieve and store it at low temperature for later use.

[0034] (3) Mix Schiele mineral powder with sugarcane lignocellulose viscose solution and stir continuously at 100 rpm for 1 h at 110°C to obtain a composite solution, wherein the mass ratio of Schiele mineral to sugarcane bagasse powder is 5:3.

[0035] (4) While the thoroughly mixed composite solution is still hot, drip 0.1 mol·L⁻¹ into the solution through the syringe needle. -1 The material is solidified into spherical shapes in an HCl aqueous solution (with the coagulation bath temperature controlled not to exceed 40℃). After standing and aging for 4 hours, the spherical product is washed three times with deionized water. After freeze-drying, spherical Schiele mineral-lignocellulose composite adsorbent material is obtained, with the following morphology: Figure 2 As shown, the spherical Scheres mineral-lignocellulose composite adsorbent material is in the form of small, reddish-yellow spheres with intact shape, uniform particle size, an average particle size of about 2 mm, and is not easily broken with good mechanical strength.

[0036] Performance testing

[0037] (1) Adsorption performance test of Sch@LCB under different pH conditions

[0038] Prepare Cr(VI) concentration of 50 mg·L -1 A series of solutions with pH values ​​of 2, 3, 4, 5, 6, 7, 8, 9, and 10 were given Sch@LCB at a dosage of 2 g / L. -1 The reaction was carried out at 298K for 24 hours, and the adsorption results were as follows: Figure 3 As shown in the figure, it can be seen that as pH increases, the equilibrium adsorption capacity (q) decreases. e The adsorption capacity gradually increased. Under slightly alkaline conditions, i.e., pH = 8–9, the adsorbent Sch@LCB exhibited better adsorption performance.

[0039] (2) Adsorption performance test of Sch@LCB at different dosages

[0040] The initial Cr(VI) concentration was 50 mg·L⁻¹. -1 Sch@LCB was added to a solution with a pH of 8.00 at dosages of 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 g·L⁻¹. -1 The reaction was carried out at 298K for 24 hours, and the adsorption results are as follows: Figure 4 As shown, as the dosage of Sch@LCB increases during the adsorption process, the adsorption capacity per unit mass of adsorbent material decreases, and the adsorption removal rate of Cr(VI) in water gradually increases.

[0041] (3) Recycling performance

[0042] Four adsorption-desorption experiments were conducted on Sch@LCB (C 0Cr =50mg·L -1 pH = 8.00, Dosage = 2 g / L -1 (t=24h), its adsorption rate data are as follows Figure 5 As shown, after four adsorption-desorption experiments, the adsorption rate of Sch@LCB for Cr(VI) remained at approximately 40%, indicating that Sch@LCB has good regeneration performance and potential for reuse.

[0043] (5) Coexisting ion experiment

[0044] In a binary system, the cations Ni(II) and Cu(II) and the anion SO42- were investigated. 2- and Cl - The effect of coexistence conditions on the adsorption and removal performance of Cr(VI) by Sch@LCB material was investigated. The concentrations of all coexisting ions were set at 0.4 mmol / L, pH = 8, temperature 298 K, and contact time 24 h. The results are as follows: Figure 6 As shown, Cl - The coexistence of Cr(VI) has virtually no effect on the adsorption and removal of Cr(VI), while the coexistence of Ni(II) promotes the adsorption and removal of Cr(VI), while SO 2 4 - Copper ions (Cu(II)) can inhibit the adsorption of Cr(VI) to some extent.

[0045] (6) Stability test

[0046] Cr(VI) was adsorbed using freshly prepared Sch@LCB and Sch@LCB stored for 1 year (pH = 8.00, C). 0Cr =50mg·L -1 (T = 298K, t = 24h) Figure 7 As shown, the adsorption capacities of the two are 13.52 mg·g⁻¹, respectively. -1 and 11.89 mg·g -1This indicates that the Sch@LCB adsorbent has a stable structure and is effective over a long period of time.

[0047] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A method for preparing a spherical Schiff mineral-lignocellulose composite adsorbent material, characterized in that, Includes the following steps: (1) Sugarcane bagasse is washed, dried and crushed to obtain sugarcane bagasse powder. 1-Allyl-3-methylimidazolium chloride, N,N-dimethylformamide, sugarcane bagasse powder and NaHCO3 are mixed in a mass ratio of 10:8-12:0.5-0.7:0.05-0.07 and stirred continuously at 105-115℃ for 0.8-1.2h to obtain a sugarcane lignocellulose viscose solution in which all components are dissolved. (2) Mix Scheres mineral with the sugarcane lignocellulose viscose solution and stir continuously at 105-115℃ for 0.8-1.2h to obtain a homogeneous liquid. The mass ratio of Scheres mineral to sugarcane bagasse powder is 4-6:

3. (3) Add the mixed liquid dropwise to a 0.1 mol·L⁻¹ solution in a coagulation bath. -1 After standing and aging in an aqueous HCl solution for 3.5-4.5 hours, the material is washed and freeze-dried to obtain the above-mentioned spherical Schiele mineral-lignocellulose composite adsorbent material. The temperature of the coagulation bath is not greater than 40°C. The preparation method of the Schiele mineral includes the following steps: slowly adding 30wt% H2O2 solution dropwise to Fe... 2+ Concentration of 2 g·L -1 The ferrous salt solution was stirred at room temperature for 24 hours, and the solids were retained to obtain the Schiele mineral. The volume ratio of the H2O2 solution to the ferrous salt solution was 1:160-240. The ferrous salt in the ferrous salt solution was ferrous sulfate and / or ferrous sulfate heptahydrate.

2. The preparation method according to claim 1, wherein the H2O2 solution is added at a rate of 1 drop every 2 minutes.

3. The preparation method according to claim 1, characterized in that, The drying temperature in step (1) is 55-60℃ and the drying time is 24h.

4. The preparation method according to claim 1, characterized in that, The sugarcane bagasse powder has a particle size of less than 100 mesh, and the Schiele mineral has a particle size of less than 200 mesh.

5. A spherical Schottky mineral-lignocellulose composite adsorbent material, characterized in that, It is prepared by the preparation method described in any one of claims 1-4.

6. The application of the spherical Schiele mineral-lignocellulose composite adsorbent material according to claim 5 in the adsorption of Cr(VI) in water.

7. An adsorbent, characterized in that, It includes the spherical Schiff mineral-lignocellulose composite adsorbent material as described in claim 5.

8. The use of the adsorbent according to claim 7 in adsorbing Cr(VI) in water.

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