CN104475023B - A kind of preparation method of modified konjac glucomannan carbosphere heavy-metal adsorption material - Google Patents

Abstract

The invention discloses a method for preparing a modified konjac glucomannan carbon microsphere heavy metal adsorption material, which comprises the steps of: (1) adding 0.5-1 weight part of konjac glucomannan into 30-50 weight parts of ultrapure water , stirring, reacting the stirred turbid liquid at 160-200° C. for 8-16 h, centrifuging the reaction liquid at 10,000 r/min for 20 min, washing the obtained solid with ethanol for 3-5 times, and drying to obtain carbon microspheres; (2) Adjust the pH of the aqueous alcohol solution to 4.5 with an acid solution with a volume fraction of 1 to 5%, add a silane coupling agent solution with a volume fraction of 1 to 3% into the aqueous alcohol solution and shake for 2 hours to obtain a modified solution; (3) take 3 ~15 parts by weight of carbon microspheres are added to 100 parts by weight of the modified solution, shaken for 3~5 hours, filtered, and the filter cake is dried at 65°C. The dried filter cake is washed with ethanol and water for 3 to 5 times, vacuum and drying to prepare the modified konjac glucomannan carbon microsphere adsorption material. The invention overcomes the disadvantages of the existing heavy metal wastewater adsorption materials such as difficult process and harsh production conditions, and prepares the heavy metal adsorption material by adopting a simple and easy-to-operate process.

Description

A kind of preparation method of modified konjac glucomannan carbon microsphere heavy metal adsorption material

technical field

The invention belongs to the field of phytochemistry and adsorption science, and in particular relates to a preparation method of konjac glucomannan carbon microsphere heavy metal adsorption material.

Background technique

Heavy metal ions mainly come from mining smelting, mechanical processing, electroplating, and petrochemical industries. Most of the wastewater generated by these industries is directly discharged into lakes, rivers, and oceans, which not only pollutes the water environment, but also rapidly deteriorates water quality. With the development of industry, its sewage discharge is increasing year by year. It has become an indisputable fact that water pollution, especially heavy metal pollution in water, seriously endangers the survival of various organisms including human beings. In recent years, the threat of heavy metal pollution to human health and living environment has attracted widespread attention of scientists from various countries, which has led to the rapid development of heavy metal wastewater treatment technology. There are various methods for treating heavy metal wastewater, which can be roughly summarized as: chemical methods, physical methods, and biological methods. However, chemical and physical methods have limited their own application prospects due to unsatisfactory treatment effects and high costs. Compared with the many disadvantages of the first two methods, the biological method has become a hot spot in the field of water treatment research because of its good treatment effect on low-concentration heavy metal wastewater, low cost, and easy waste disposal. Recently, many researchers at home and abroad have modified some agricultural and forestry by-products or agricultural wastes, and developed some adsorbents with different characteristics and functions. For example, wood chips, persimmon residues, mushroom roots, tea residues, etc. are modified to make adsorbents, but they have not been well promoted because of the complicated processing process.

Konjac is a perennial plant, mainly distributed in Southeast Asia, Africa and other places; in China, Japan, Myanmar, Vietnam, Indonesia and other countries, the konjac production areas in China are mainly distributed in Yunnan, Guizhou, Sichuan, southern Shaanxi and western Hubei. Konjac resources are the most abundant in the mountains around the Sichuan Basin. Its plant height is about 40-70 cm, the petiole is thick and long like a stem, cylindrical, light green, with dark purple spots, palmate compound leaves, and purple-red flowers. There are bulbs in the ground, which are flat and round, with a diameter of more than 25cm. They are rich in nutrients and contain more than 45% of konjac polysaccharides. Konjac polysaccharides are konjac glucomannan, also known as KGM. It has various physical and chemical properties such as water solubility, thickening, suspension, gel, film formation, bonding, and stability. Due to its physical and chemical properties such as high viscosity, high water absorption, and fast expansion, the processing technology of konjac is limited. Existing konjac food The purity of konjac glucomannan is generally low, and people take very little glucomannan. Konjac glucomannan contains carbon, hydrogen, and oxygen elements, and its surface contains a variety of functional groups, such as alcoholic hydroxyl groups and carboxyl anions, which are easy to be modified and can be made into adsorbents, and it also has the ability to adsorb heavy metal ions. The adsorption effect is better.

In the patent document CN102161711A, konjac glucomannan is chemically modified to prepare a heavy metal adsorption material, but the preparation method of the adsorption material is complicated, the process is difficult, the production conditions are harsh, and industrialization is difficult. In the master's thesis "Konjac Glucomannan Cross-linked Carboxymethyl Modification and Its Adsorption and Desorption Properties of Metal Ions", a preparation method of cross-linked carboxymethyl modified adsorption material was introduced, and the research was carried out. Its adsorption performance on heavy metals, the preparation scheme of this adsorption material is complex, the conditions are difficult to control, and the degree of substitution of the obtained konjac glucomannan modified product is not very high.

Contents of the invention

As a result of various extensive and meticulous studies and experiments, the inventors of the present invention have found that konjac glucomannan is subjected to carbonization and modification treatment. The adsorption performance of konjac glucomannan can be greatly improved. Based on this finding, the present invention has been accomplished.

An object of the present invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages as will be described hereinafter.

Another object of the present invention is to provide a preparation method of modified konjac glucomannan carbon microsphere heavy metal adsorption material, through carbonization treatment, konjac glucomanose can be made into micro-nano balls, and through modification treatment of silane coupling agent, the The adsorption performance of konjac glucomannan can be greatly improved.

In order to realize these purposes and other advantages according to the present invention, a kind of preparation method of modified konjac glucomannan carbon microsphere heavy metal adsorption material is provided, comprising the following steps:

Step 1: Add 0.5-1 part by weight of konjac glucomannan into 30-50 parts by weight of ultra-pure water, stir to obtain a viscous turbid liquid, and place the viscous turbid liquid in a hydrothermal reaction at 160-200°C Heating in the kettle for 8-16 hours, then centrifuging the reaction solution at a speed of 10,000r/min for 20 minutes, washing the centrifuged solid with ethanol for 3-5 times, and then vacuum-drying at 50-80°C for 12-24 hours to obtain konjac glucan Polysaccharide carbon microspheres;

Step 2, using an acid solution with a volume fraction of 1 to 5% to adjust the pH of the alcohol aqueous solution to 4.5, adding a silane coupling agent solution with a volume fraction of 1 to 3% into the alcohol aqueous solution and shaking for 2 hours to obtain a modified solution; The volume ratio of alcohol to water in the alcohol aqueous solution is 1:1, and the volume ratio of the alcohol aqueous solution to the silane coupling agent solution is 1:0.3～0.5;

Step 3: Add 3 to 15 parts by weight of the konjac glucomannan carbon microspheres prepared in step 1 to 100 parts by weight of the modified liquid prepared in step 2, shake for 3 to 5 hours, filter, and dry the filter cake at 65°C. The dried filter cake is washed 3 to 5 times with ethanol and water at a volume ratio of 1:1, and vacuum dried at 50 to 80° C. for 12 to 24 hours to prepare the modified konjac glucomannan carbon microsphere adsorption material.

Preferably, one of acetic acid, sulfuric acid and nitric acid is used to replace the hydrochloric acid in the acid solution in step two.

Preferably, ethanol is used to replace the methanol in the alcohol aqueous solution in step 2.

Preferably, one of 3-aminopropyltrimethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane is used to replace the silane coupling agent 3-mercaptopropyltriethoxy in step two base silane.

The invention at least includes the following beneficial effects: the preparation method overcomes the disadvantages of high cost, complex processing, difficult process, and harsh production conditions of the prior art adsorption materials for treating heavy metal wastewater, and adopts a simple and easy-to-operate process to prepare heavy metal adsorption Material, the present invention selects konjac glucomannan with rich sources and low price, and carries out carbonization and modification treatment to it, carbonization treatment can make konjac glucomannan form micro carbon spheres, modification treatment of silane coupling agent can make The adsorption performance of konjac glucomannan can be greatly improved, and it can be used in the process of treating heavy metal ion wastewater, which can greatly reduce the cost of heavy metal ion wastewater treatment, and has economic value and environmental protection significance.

Other advantages, objectives and features of the present invention will partly be embodied through the following descriptions, and partly will be understood by those skilled in the art through the study and practice of the present invention.

Description of drawings:

Figure 1 is a scanning electron micrograph of modified konjac glucomannan carbon microspheres prepared in Example 1 of the present invention.

detailed description:

The present invention will be described in further detail below in conjunction with the embodiments and accompanying drawings, so that those skilled in the art can implement it with reference to the description.

It should be understood that terms such as "having", "comprising" and "including" as used herein do not entail the presence or addition of one or more other elements or combinations thereof.

Example 1:

Step 1. Add 0.7g of konjac glucomannan to 40g of ultrapure water, stir to obtain a sticky cloudy liquid, heat the sticky cloudy liquid in a hydrothermal reactor at 180°C for 12 hours, and then dissolve the reaction solution Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 3 times, and then vacuum-dry at 60°C for 24h to obtain konjac glucomannan carbon microspheres;

Step 2: Adjust the pH of 100 mL of aqueous ethanol solution to 4.5 with acetic acid solution with a volume fraction of 5%, add 30 mL of 3-mercaptopropyltriethoxysilane solution with a volume fraction of 1.5% into the aqueous ethanol solution and shake for 2 hours to obtain a modified Liquid; The volume ratio of alcohol and water in the ethanol aqueous solution is 1:1;

Step 3: Take 5g of konjac glucomannan carbon microspheres prepared in step 1 and add them to 100g of the modified liquid prepared in step 2, shake for 3 hours, filter, and dry the filter cake at 65°C, and use the dried filter cake with The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing three times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 50°C for 24 hours.

Fig. 1 shows the scanning electron micrograph of the modified konjac glucomannan carbon microspheres prepared in this example.

Example 2:

Step 1. Add 0.5g of konjac glucomannan to 30g of ultrapure water, stir to obtain a viscous turbid solution, heat the viscous turbid solution in a hydrothermal reactor at 160°C for 8 hours, and then dissolve the reaction solution Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 3 times, and then vacuum-dry it at 50°C for 24h to obtain konjac glucomannan carbon microspheres;

Step 2: Adjust the pH of 100 mL of aqueous ethanol solution to 4.5 with 1% acetic acid solution by volume fraction, add 30 mL of 3-mercaptopropyltriethoxysilane solution with 1% volume fraction into the aqueous ethanol solution and shake for 2 hours to obtain modified liquid; the volume ratio of alcohol to water in the ethanol aqueous solution is 1:1;

Step 3: Take 3g of konjac glucomannan carbon microspheres prepared in step 1 and add them to 100g of the modified liquid prepared in step 2, shake for 3 hours, filter, and dry the filter cake at 65°C, and use the dried filter cake with The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing three times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 50°C for 24 hours.

Example 3:

Step 1. Add 1g of konjac glucomannan to 50g of ultrapure water, stir to obtain a viscous turbid liquid, heat the viscous turbid liquid in a hydrothermal reactor at 200°C for 16 hours, and then place the reaction solution in Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 5 times, and then vacuum-dry at 80°C for 12h to obtain konjac glucomannan carbon microspheres;

Step 2. Adjust the pH of 100 mL of aqueous ethanol solution to 4.5 with 5% acetic acid solution by volume fraction, add 50 mL of 3-mercaptopropyltriethoxysilane solution with 3% volume fraction into the aqueous ethanol solution and shake for 2 hours to obtain modified liquid; the volume ratio of alcohol to water in the ethanol aqueous solution is 1:1;

Step 3: Add 15g of the konjac glucomannan carbon microspheres prepared in step 1 to 100g of the modified solution prepared in step 2, shake for 5 hours, filter, and dry the filter cake at 65°C, and use the dried filter cake with The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing five times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 80°C for 12 hours.

Example 4:

Step 1. Add 0.8g of konjac glucomannan to 40g of ultrapure water, stir to obtain a sticky cloudy liquid, heat the sticky cloudy liquid in a hydrothermal reactor at 180°C for 12 hours, and then dissolve the reaction solution Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 4 times, and then vacuum-dry it at 70°C for 20h to obtain konjac glucomannan carbon microspheres;

Step 2: Adjust the pH of 100 mL of aqueous ethanol solution to 4.5 with 3% acetic acid solution by volume fraction, add 40 mL of 3-mercaptopropyltriethoxysilane solution with 2% volume fraction into the aqueous ethanol solution and shake for 2 hours to obtain modified liquid; the volume ratio of alcohol to water in the ethanol aqueous solution is 1:1;

Step 3: Add 10 g of konjac glucomannan carbon microspheres prepared in step 1 to 100 g of the modified solution prepared in step 2, shake for 4 hours, filter, and dry the filter cake at 65 ° C. Use the dried filter cake The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing four times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 60°C for 18 hours.

In order to illustrate the effect of the present invention, the inventor provides comparative experiments as follows:

Comparative example 1:

Step 1. Add 0.2g of konjac glucomannan to 30g of ultrapure water, stir to obtain a viscous turbid solution, heat the viscous turbid solution in a hydrothermal reactor at 160°C for 8 hours, and then dissolve the reaction solution Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 3 times, and then vacuum-dry it at 50°C for 24h to obtain konjac glucomannan carbon microspheres;

Step 2: Adjust the pH of 100 mL of aqueous ethanol solution to 4.5 with 1% acetic acid solution by volume fraction, add 30 mL of 3-mercaptopropyltriethoxysilane solution with 1% volume fraction into the aqueous ethanol solution and shake for 2 hours to obtain modified liquid; the volume ratio of alcohol to water in the ethanol aqueous solution is 1:1;

Step 3: Take 3g of konjac glucomannan carbon microspheres prepared in step 1 and add them to 100g of the modified liquid prepared in step 2, shake for 3 hours, filter, and dry the filter cake at 65°C, and use the dried filter cake with The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing three times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 50°C for 24 hours.

Comparative example 2:

Step 1. Add 2g of konjac glucomannan to 30g of ultrapure water, stir to obtain a viscous turbid liquid, heat the viscous turbid liquid in a hydrothermal reactor at 160°C for 8 hours, and then put the reaction liquid in Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 3 times, and then vacuum dry at 50°C for 24h to obtain konjac glucomannan carbon microspheres;

Step 2: Adjust the pH of 100 mL of aqueous ethanol solution to 4.5 with 1% acetic acid solution by volume fraction, add 30 mL of 3-mercaptopropyltriethoxysilane solution with 1% volume fraction into the aqueous ethanol solution and shake for 2 hours to obtain modified liquid; the volume ratio of alcohol to water in the ethanol aqueous solution is 1:1;

Step 3: Take 3g of konjac glucomannan carbon microspheres prepared in step 1 and add them to 100g of the modified liquid prepared in step 2, shake for 3 hours, filter, and dry the filter cake at 65°C, and use the dried filter cake with The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing three times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 50°C for 24 hours.

Comparative example 3:

Step 1. Add 0.5g of konjac glucomannan to 30g of ultrapure water, stir to obtain a viscous turbid solution, heat the viscous turbid solution in a hydrothermal reactor at 100°C for 8 hours, and then dissolve the reaction solution Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 3 times, and then vacuum-dry it at 50°C for 24h to obtain konjac glucomannan carbon microspheres;

Step 2: Adjust the pH of 100 mL of aqueous ethanol solution to 4.5 with 1% acetic acid solution by volume fraction, add 30 mL of 3-mercaptopropyltriethoxysilane solution with 1% volume fraction into the aqueous ethanol solution and shake for 2 hours to obtain modified liquid; the volume ratio of alcohol to water in the ethanol aqueous solution is 1:1;

Step 3: Take 3g of konjac glucomannan carbon microspheres prepared in step 1 and add them to 100g of the modified liquid prepared in step 2, shake for 3 hours, filter, and dry the filter cake at 65°C, and use the dried filter cake with The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing three times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 50°C for 24 hours.

Comparative example 4:

Step 1. Add 1g of konjac glucomannan to 50g of ultrapure water, stir to obtain a viscous turbid liquid, heat the viscous turbid liquid in a hydrothermal reactor at 200°C for 16 hours, and then place the reaction solution in Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 5 times, and then vacuum-dry at 80°C for 12h to obtain konjac glucomannan carbon microspheres;

Step 2. Adjust the pH of 100 mL of aqueous ethanol solution to 4.5 with 5% acetic acid solution by volume fraction, add 50 mL of 3-mercaptopropyltriethoxysilane solution with 3% volume fraction into the aqueous ethanol solution and shake for 2 hours to obtain modified liquid; the volume ratio of alcohol to water in the ethanol aqueous solution is 1:1;

Step 3: Add 1 g of konjac glucomannan carbon microspheres prepared in step 1 to 100 g of the modified liquid prepared in step 2, shake for 5 hours, filter, and dry the filter cake at 65 ° C. Use the dried filter cake The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing five times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 80°C for 12 hours.

Comparative example 5:

Step 1. Add 1g of konjac glucomannan to 50g of ultrapure water, stir to obtain a viscous turbid liquid, heat the viscous turbid liquid in a hydrothermal reactor at 200°C for 16 hours, and then place the reaction solution in Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 5 times, and then vacuum-dry at 80°C for 12h to obtain konjac glucomannan carbon microspheres;

Step 2. Adjust the pH of 100 mL of aqueous ethanol solution to 4.5 with 5% acetic acid solution by volume fraction, add 50 mL of 3-mercaptopropyltriethoxysilane solution with 3% volume fraction into the aqueous ethanol solution and shake for 2 hours to obtain modified liquid; the volume ratio of alcohol to water in the ethanol aqueous solution is 1:1;

Step 3: Add 20 g of konjac glucomannan carbon microspheres prepared in step 1 to 100 g of the modified solution prepared in step 2, shake for 5 hours, filter, and dry the filter cake at 65 ° C. Use the dried filter cake with The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing five times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 80°C for 12 hours.

Comparative example 6:

Step 1. Add 0.8g of konjac glucomannan to 40g of ultrapure water, stir to obtain a sticky cloudy liquid, heat the sticky cloudy liquid in a hydrothermal reactor at 180°C for 12 hours, and then dissolve the reaction solution Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 4 times, and then vacuum-dry it at 70°C for 20h to obtain konjac glucomannan carbon microspheres;

Step 2. Adjust the pH of 100 mL of ethanol aqueous solution to 4.5 with 3% acetic acid solution by volume fraction, add 40 mL of 3-mercaptopropyltriethoxysilane solution with 0.5% volume fraction into the aqueous ethanol solution and shake for 2 hours to obtain modified liquid; the volume ratio of alcohol to water in the ethanol aqueous solution is 1:1;

Step 3: Add 10 g of konjac glucomannan carbon microspheres prepared in step 1 to 100 g of the modified solution prepared in step 2, shake for 4 hours, filter, and dry the filter cake at 65 ° C. Use the dried filter cake The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing four times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 60°C for 18 hours.

Comparative example 7:

Step 1. Add 0.8g of konjac glucomannan to 40g of ultrapure water, stir to obtain a sticky cloudy liquid, heat the sticky cloudy liquid in a hydrothermal reactor at 180°C for 12 hours, and then dissolve the reaction solution Centrifuge at a speed of 10000r/min for 20min, wash the centrifuged solid with ethanol for 4 times, and then vacuum-dry it at 70°C for 20h to obtain konjac glucomannan carbon microspheres;

Step 2: Adjust the pH of 100 mL of aqueous ethanol solution to 4.5 with 3% acetic acid solution by volume fraction, add 40 mL of 3-mercaptopropyltriethoxysilane solution with 5% volume fraction into the aqueous ethanol solution and shake for 2 hours to obtain the modified liquid; the volume ratio of alcohol to water in the ethanol aqueous solution is 1:1;

Step 3: Add 10 g of konjac glucomannan carbon microspheres prepared in step 1 to 100 g of the modified solution prepared in step 2, shake for 4 hours, filter, and dry the filter cake at 65 ° C. Use the dried filter cake The modified konjac glucomannan carbon microspheres adsorption material was obtained by washing four times with ethanol and water at a volume ratio of 1:1, and drying in vacuum at 60°C for 18 hours.

The adsorption materials prepared in Examples 1-4 and Comparative Examples 1-7 above were used for static adsorption research on heavy metal lead ions and cadmium ions, respectively.

Mix 20 mg of the adsorption material prepared in the above-mentioned Examples 1-4 and Comparative Examples 1-7 with 100 mL of 50 mg/L lead ion solution, adjust the pH to 4, place it on a shaker for 2 h, the rotation speed is 130 rpm, and the adsorption temperature is 25 °C ;

Take 20 mg of the adsorption materials prepared in the above-mentioned Examples 1-4 and Comparative Examples 1-7 and mix them with 100 mL of 40 mg/L cadmium ion solution, adjust the pH to 4, place on a shaking table for 2 h, the rotation speed is 130 rpm, and the adsorption temperature is 25 °C ;

The adsorption effects of the two ions are shown in Table 1, and the removal rate of heavy metal ions is calculated by the following formula (1),

Removal rate = (C _o -C _m )/C _o × 100% (1)

Among them, C _o is the concentration of heavy metal ions before adsorption, and C _m is the concentration of heavy metal ions after adsorption.

The adsorption capacity of the adsorbent material is calculated by the following formula (2),

Adsorption capacity=(C _o -C _e )V/m(2)

Among them, C _o is the concentration of heavy metal ions before adsorption, C _e is the concentration of heavy metal ions after adsorption equilibrium, V is the volume of heavy metal solution added, and m is the mass of adsorption material added.

Table 1

As can be seen from Table 1, embodiment 1～4 owing to have adopted raw material and process parameter in the ratio scope of the present invention, it is better to the adsorption effect of heavy metal lead ion and cadmium ion solution, and removal rate is all greater than 94%, to lead The adsorption capacity of ions is greater than 100mg/g, and the adsorption capacity of cadmium ions is greater than 50mg/g.

And the raw material that adopts in the comparative example and the ratio of process parameter are not within the ratio scope described in the present invention, therefore the adsorption effect to heavy metal lead ion and cadmium ion solution is relatively poor, removal rate is all less than 90%, to lead ion The adsorption capacity is less than 80mg/g, and the adsorption capacity for cadmium ions is less than 40mg/g.

Comparative example 1 and comparative example 2 are compared with embodiment 2, and the difference is that the amount of konjac glucomannan added in step 1 of comparative example 1 is 0.2g, and the amount of konjac glucomannan added in step 1 of comparative example 2 It is 2g, both of which are not within the ratio range described in the present invention, which will lead to the inhomogeneous microsphere structure after konjac glucomannan carbonization, and the adsorption material obtained is all lower than the removal rate and adsorption capacity of heavy metal ions. Adsorbent material prepared in Example 2.

Compared with Example 2, Comparative Example 3 differs in that the reaction temperature in Step 1 of Comparative Example 3 is 100° C., which is not within the reaction temperature of 160 to 200° C. in the present invention, and the temperature is lower. Konjac glucan The carbonization of the polysaccharide is not complete, and the particle size of the obtained microspheres is relatively large, so the removal rate and adsorption capacity of the adsorption material for heavy metal ions are lower than those of the adsorption material prepared in Example 2.

Comparative example 4 and comparative example 5 are compared with embodiment 3, and the difference is that the amount of konjac glucomannan carbon microspheres added in step 3 of comparative example 4 is 1g, and the amount of konjac glucomannan added in step 1 of comparative example 5 The amount of carbon microspheres is 20g, both of which are not within the ratio range described in the present invention. When the amount of konjac glucomannan carbon microspheres is lower than the range, it will cause konjac glucomannan carbon microspheres Covered by a large amount of 3-mercaptopropyltriethoxysilane, which is not conducive to the adsorption of heavy metal ions, when the amount of konjac glucomannan carbon microspheres is higher than the stated range, it will cause konjac glucomannan carbon microspheres The modification of the spheres is incomplete and cannot effectively play the role of 3-mercaptopropyltriethoxysilane, so the removal rate and adsorption capacity of the obtained adsorption material for heavy metal ions are lower than those prepared in Example 3.

Compared with Example 4, Comparative Example 6 and Comparative Example 7, the difference is that the volume fraction of 3-mercaptopropyltriethoxysilane added in the preparation of step two modified liquid in Comparative Example 6 is 0.5%, and that of Comparative Example 7 The volume fraction of the 3-mercaptopropyltriethoxysilane added in the preparation of the modified liquid in step 2 is 5%, both of which are not within the proportion range of 1 to 3% described in the present invention. When 3-mercaptopropyltriethoxysilane When the volume fraction of propyltriethoxysilane is lower than the range, the modification of konjac glucomannan carbon microspheres will be incomplete in step 3, and the 3-mercaptopropyltriethoxy group cannot be effectively brought into play. The effect of silane, when the volume fraction of 3-mercaptopropyltriethoxysilane is higher than said range, in step 3, konjac glucomannan carbon microspheres will be covered by a large amount of 3-mercaptopropyltriethoxy Silane covered, so the removal rate and adsorption capacity of the obtained adsorbent material for heavy metal ions are lower than the adsorbent material prepared in Example 4.

It can be seen that the raw materials used in the present invention are in the stated proportion, and during the preparation process of the adsorbent material, each parameter is within the stated range, and the prepared adsorbent material has better adsorption performance on heavy metal ions.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and implementation, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Therefore, the invention is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (4)

1. a preparation method of modified konjac glucomannan carbon microspheres heavy metal adsorption material, is characterized in that, comprises the following steps: Step 1: Add 0.5-1 part by weight of konjac glucomannan into 30-50 parts by weight of ultra-pure water, stir to obtain a viscous turbid liquid, and place the viscous turbid liquid in a hydrothermal reaction at 160-200°C Heating in the kettle for 8-16 hours, then centrifuging the reaction solution at a speed of 10,000r/min for 20 minutes, washing the centrifuged solid with ethanol for 3-5 times, and then vacuum-drying at 50-80°C for 12-24 hours to obtain konjac glucan Polysaccharide carbon microspheres; Step 2, using an acid solution with a volume fraction of 1 to 5% to adjust the pH of the alcohol aqueous solution to 4.5, adding a silane coupling agent solution with a volume fraction of 1 to 3% into the alcohol aqueous solution and shaking for 2 hours to obtain a modified solution; The volume ratio of alcohol to water in the alcohol aqueous solution is 1:1, and the volume ratio of the alcohol aqueous solution to the silane coupling agent solution is 1:0.3-0.5; the acid in the acid solution is hydrochloric acid; The alcohol is methanol; the silane coupling agent is 3-mercaptopropyltriethoxysilane; Step 3: Add 3 to 15 parts by weight of the konjac glucomannan carbon microspheres prepared in step 1 to 100 parts by weight of the modified liquid prepared in step 2, shake for 3 to 5 hours, filter, and dry the filter cake at 65°C. The dried filter cake is washed 3 to 5 times with ethanol and water at a volume ratio of 1:1, and vacuum dried at 50 to 80° C. for 12 to 24 hours to prepare the modified konjac glucomannan carbon microsphere adsorption material. 2. the preparation method of modified konjac glucomannan carbon microspheres heavy metal adsorption material according to claim 1, is characterized in that, adopts a kind of in acetic acid, sulfuric acid, nitric acid to replace the hydrochloric acid in the acid solution in step two. 3. the preparation method of modified konjac glucomannan carbon microspheres heavy metal adsorption material according to claim 1, is characterized in that, adopts ethanol to replace the methanol in the alcohol aqueous solution in step two. 4. the preparation method of modified konjac glucomannan carbon microspheres heavy metal adsorption material according to claim 1 is characterized in that, adopts 3-aminopropyltrimethoxysilane, vinyltrimethoxysilane, vinyl One of the triethoxysilanes replaces the silane coupling agent 3-mercaptopropyltriethoxysilane in step two.