阅读说明：本技术 单质硫改性生物炭、其制备方法及其应用 (Elemental sulfur modified biochar, and preparation method and application thereof ) 是由 刘强 齐婷 于 2021-06-09 设计创作，主要内容包括：本发明公开了一种单质硫改性生物炭、其制备方法及其应用,以原始生物质为原料,清洗、烘干、粉碎、过筛、干燥备用,然后将干燥后的原始生物质通过初次热解制备原始生物炭；将原始生物炭和单质硫均匀混合,再次热解,过筛,得到硫改性生物炭产品。本发明利用生物炭来制备一种廉价,绿色,高效的单质硫改性生物炭材料作为吸附剂,本发明选择重金属铬为研究对象,采用单质硫改性生物炭,高效以及低成本去除水体中六价铬。本发明方法简单易行,成本低,适合推广使用。(The invention discloses elemental sulfur modified biochar, a preparation method and application thereof, wherein original biomass is taken as a raw material, and is cleaned, dried, crushed, screened and dried for later use, and then the dried original biomass is subjected to primary pyrolysis to prepare the original biochar; and uniformly mixing the original biochar with elemental sulfur, pyrolyzing the mixture again, and sieving the pyrolyzed mixture to obtain a sulfur modified biochar product. According to the invention, the biochar is used for preparing the cheap, green and efficient elemental sulfur modified biochar material as the adsorbent, heavy metal chromium is selected as a research object, the elemental sulfur modified biochar is adopted, and hexavalent chromium in a water body is removed efficiently and at low cost. The method is simple and easy to implement, low in cost and suitable for popularization and application.)

1. The preparation method of the elemental sulfur modified biochar is characterized by comprising the following steps:

(1) pretreatment of original biochar:

the method comprises the following steps of taking original biomass as a raw material, cleaning, drying, crushing, screening and drying for later use, and then preparing original biochar from the dried original biomass through primary pyrolysis;

(2) preparing sulfur modified biochar:

and (2) uniformly mixing the original biochar prepared in the step (1) with elemental sulfur, pyrolyzing again, and sieving to obtain a sulfur modified biochar product.

2. The method for preparing the elemental sulfur-modified biochar according to claim 1, wherein: in the step (1), the original biomass is cleaned by deionized water, then is dried for at least 72 hours in an oven with the temperature of not lower than 60 ℃, is crushed by a crusher after being dried, is sieved and is stored in a dryer for standby.

3. The method for preparing the elemental sulfur-modified biochar according to claim 1, wherein: in the step (1), 3-4 g of dried original biomass is weighed each time and sieved by a 100-mesh sieve, the sieved and collected original biomass is placed in a quartz boat, a pyrolysis tube is placed in the quartz boat, and then the quartz boat is placed in a tubular electric furnace; introducing carrier gas, heating to a temperature not lower than 100 ℃, staying, heating to 300-600 ℃, and carbonizing at constant temperature for at least 2 h; and (3) after the pyrolysis time is reached, automatically stopping heating by the program, continuously introducing carrier gas, naturally cooling to room temperature, taking out a solid product, namely the original biochar, weighing, grinding, sieving by a 100-mesh sieve, and sealing and storing.

4. The method for preparing the elemental sulfur-modified biochar according to claim 3, wherein: in the step (1), the carrier gas is N₂The gas flow is not lower than 120 mL/min;

or, in the step (1), when pyrolysis is carried out, the temperature is increased from room temperature to be not lower than 100 ℃ at a heating rate of not lower than 10 ℃/min, and the pyrolysis is kept for at least 20min, so that oxygen in the tubular furnace is exhausted and the biomass is in a dry state.

5. The method for preparing the elemental sulfur-modified biochar according to claim 3, wherein: in the step (1), heating to a specified temperature of 300-600 ℃ at a speed of not less than 10 ℃/min.

6. The method for preparing the elemental sulfur-modified biochar according to claim 1, wherein: in the step (2), 3-4 g of the original biochar prepared in the step (1) is weighed, and the mass ratio of sulfur to carbon (0.25-3): 1 to obtain a pyrolysis raw material mixture; putting the pyrolysis raw material mixture into a quartz boat, then putting the quartz boat into a tubular electric furnace for secondary pyrolysis, introducing carrier gas, firstly heating to be not less than 100 ℃, and staying; then the temperature is reduced to 300-700 ℃ and the secondary constant-temperature carbonization time is controlled to be 5-120 min; and (3) after the pyrolysis time is reached, automatically stopping heating, continuously introducing carrier gas, naturally cooling to room temperature, taking out the solid product, sieving by a 100-mesh sieve to obtain the sulfur modified biochar product, and sealing and storing.

7. The method for preparing the elemental sulfur-modified biochar according to claim 6, wherein: in the step (2), the temperature for the second pyrolysis is 450-700 ℃.

8. The method for preparing the elemental sulfur-modified biochar according to claim 6, wherein: in the step (2), the secondary constant-temperature carbonization time of the secondary pyrolysis is 60-120 min.

9. An elemental sulfur modified biochar, which is characterized in that: the elemental sulfur modified biochar is prepared by the method for preparing the elemental sulfur modified biochar as claimed in any one of claims 1-9.

10. The application of the elemental sulfur modified biochar is characterized in that: the use of the elemental sulfur-modified biochar of claim 9 for removing hexavalent chromium from water.

Technical Field

The invention relates to the field of heavy metal treatment, in particular to a preparation method and application of elemental sulfur modified biochar for removing hexavalent chromium.

Background

In recent years, the progress of urbanization, industrialization and agriculture intensification is accelerating, which leads to the increasing of environmental pollution, especially water pollution. In China, a part of surface water is seriously polluted by chromium, and the chromium pollution of underground water is very common. The chromium pollution in the environment mainly comes from the discharge of chromium-containing wastewater, waste gas and waste residues in the industries of electroplating, tanning, printing and dyeing and the like. In general, cr (vi) in chromic acid and calcium chromate is a major harmful component in chromium slag, and tends to increase environmental pollution. The long-term stacked chromium slag can pollute soil, surface water and underground water after being leached and washed by rainwater; the increasing demand of chromium and its compounds in industry promotes the rapid development of chromium salt production, and becomes a great amount of chromium-containing waste gas emission source. Trivalent chromium is not easy to be absorbed in stomach and intestine, so the toxicity is not large, and the toxicity of hexavalent Cr (VI) is about 100 times higher than that of trivalent Cr (III) and the teratogenicity is 1000 times higher. Hexavalent chromium or metabolic intermediates thereof in vivo can be combined with nucleic acid and nucleoprotein, so that genetic code is changed, cell mutation and even canceration are caused, and the hexavalent chromium or the metabolic intermediates thereof in vivo is one of three internationally recognized carcinogenic metals.

The method for removing chromium in water mainly comprises three main categories: chemical, biological, physicochemical. The chemical methods are divided into chemical precipitation methods and oxidation-reduction methods; the physical and chemical methods include adsorption, membrane separation, and ion exchange; the biological method comprises a biological flocculation method, a biological adsorption method, phytoremediation and the like. However, the method has some disadvantages, such as that a great amount of medicament is needed in chemical precipitation, which causes secondary pollution; the animal and plant combined repairing method does not necessarily have obvious treatment repairing effect and the like in a long time. The adsorption method is the most common method for treating wastewater, and is simple to operate, convenient and easy to implement, for example, the adsorbent has high cost due to small capacity.

Biochar is a substance rich in carbon, is produced by pyrolyzing biomass under the condition of limited oxygen, has developed internal pores and larger specific surface area, contains rich oxygen-containing functional groups on the surface, and has one of important functions. The biochar has obvious treatment and restoration effects on heavy metals in aquatic ecological environment, but ordinary unmodified biochar basically loses a large amount of surface functions at a high temperature, so that the degradation treatment effect on the heavy metals is greatly reduced. The pore structure and specific surface area of the biochar generated at a lower temperature are very small, so that the treatment effect is not very obvious, and researchers change the direction into modifying the biochar by other substances with special functions to synthesize the carbon composite material with more obvious effect. Researchers have used Fe-Zn modified biochar to greatly increase the adsorption capacity of chromium, but released metal ions can cause secondary pollution.

Disclosure of Invention

In order to solve the problems of the prior art, the invention aims to overcome the defects in the prior art and provide the elemental sulfur modified biochar, the preparation method and the application thereof.

In order to achieve the purpose of the invention, the invention adopts the following technical scheme:

a preparation method of elemental sulfur modified biochar comprises the following steps:

(1) pretreatment of original biochar:

the method comprises the following steps of taking original biomass as a raw material, cleaning, drying, crushing, screening and drying for later use, and then preparing original biochar from the dried original biomass through primary pyrolysis;

(2) preparing sulfur modified biochar:

and (2) uniformly mixing the original biochar prepared in the step (1) with elemental sulfur, pyrolyzing again, and sieving to obtain a sulfur modified biochar product.

Preferably, in the step (1), the raw biomass is corn stalks.

Preferably, in the step (1), the original biomass is cleaned by deionized water, and then is dried in an oven at a temperature of not lower than 60 ℃ for at least 72 hours, and after drying, the biomass is crushed by a crusher, sieved and stored in a dryer for standby.

Preferably, in the step (1), 3-4 g of dried original biomass is weighed each time and sieved by a 100-mesh sieve, the sieved and collected original biomass is placed in a quartz boat, a pyrolysis tube is placed in the quartz boat, and then the quartz boat is placed in a tube type electric furnace; introducing carrier gas, heating to a temperature not lower than 100 ℃, staying, heating to 300-600 ℃, and carbonizing at constant temperature for at least 2 h; and (3) after the pyrolysis time is reached, automatically stopping heating by the program, continuously introducing carrier gas, naturally cooling to room temperature, taking out a solid product, namely the original biochar, weighing, grinding, sieving by a 100-mesh sieve, and sealing and storing. Preferably, the raw biochar preparation temperature of the invention is 300 ℃.

Preferably, in the step (1), the carrier gas is N₂The gas flow is not lower than 120 mL/min;

preferably, in the step (1), when pyrolysis is carried out, the temperature is increased from room temperature to not less than 100 ℃ at a heating rate of not less than 10 ℃/min, and the pyrolysis is kept for at least 20min, so that oxygen in the tubular furnace is exhausted and the biomass is in a dry state.

Preferably, in the step (1), the heating is carried out at a rate of not less than 10 ℃/min to a specified temperature of 300-600 ℃.

Preferably, in the step (2), 3-4 g of the raw biochar prepared in the step (1) is weighed, and the mass ratio of sulfur to carbon is (0.25-3): 1 to obtain a pyrolysis raw material mixture; putting the pyrolysis raw material mixture into a quartz boat, then putting the quartz boat into a tubular electric furnace for secondary pyrolysis, introducing carrier gas, firstly heating to be not less than 100 ℃, and staying; then the temperature is reduced to 300-700 ℃ and the secondary constant-temperature carbonization time is controlled to be 5-120 min; and (3) after the pyrolysis time is reached, automatically stopping heating, continuously introducing carrier gas, naturally cooling to room temperature, taking out the solid product, sieving by a 100-mesh sieve to obtain the sulfur modified biochar product, and sealing and storing. Preferably, the sulfur and carbon are mixed in a mass ratio of 2: 1, and mixing uniformly to obtain a pyrolysis raw material mixture.

Preferably, in the step (2), the temperature for pyrolysis again is 450-700 ℃. Preferably, the secondary pyrolysis temperature in the present invention is 450 ℃.

Preferably, in the step (2), the second constant temperature carbonization time of the second pyrolysis is 60-120 min. Preferably, the secondary carbonization time is 60 min.

The elemental sulfur modified biochar is prepared by the preparation method of the elemental sulfur modified biochar.

The invention relates to application of elemental sulfur modified biochar, which is used for removing hexavalent chromium in water.

Preferably, the treatment method for removing hexavalent chromium in the water body by using the elemental sulfur modified biochar comprises the following steps: the initial concentration of the chromium-containing solution is not less than 100mg/L, the pH value is not more than 4.0, the sulfur modified biochar is added into the chromium-containing solution to be not less than 0.2g, and the reaction time is at least 24 h.

Compared with the prior art, the invention has the following obvious and prominent substantive characteristics and remarkable advantages:

1. according to the invention, the biochar is prepared by taking corn straws as a raw material, elemental sulfur is used for modifying the biochar, and the modified sulfur-containing biochar is used for removing Cr (VI) ions in water;

2. the method improves the removal rate of the sulfur-modified biochar on six-grade chromium in water compared with biochar, and has the characteristics of greenness, simple preparation and low cost;

3. the method is simple and easy to implement, low in cost and suitable for popularization and application.

Drawings

FIG. 1 is a graph of the effect of secondary pyrolysis time on total chromium removal.

FIG. 2 is a graph of the effect of secondary pyrolysis temperature on total chromium removal.

FIG. 3 is a graph of the effect of raw biochar preparation temperature on total chromium removal.

FIG. 4 is a graph of the effect of sulfur/carbon doping ratio on total chromium removal.

FIG. 5 is a response plot of sulfur-modified carbon optimized for total chromium removal as a response value.

FIG. 6 is a graph of the effect of initial solution pH on the removal of chromium from sulfur-modified biochar.

Fig. 7 is a graph of adsorption kinetics data of sulfur-modified biochar on cr (vi).

FIG. 8 is a temperature contour diagram of adsorption of sulfur-modified biochar on Cr (VI).

FIG. 9 is an SEM-EDS image of sulfur-modified biochar and unmodified biochar.

FIG. 10 is an XPS chart of before and after adsorption of sulfur-modified biochar and before and after modification.

Detailed Description

The above-described scheme is further illustrated below with reference to specific embodiments, which are detailed below:

example 1

In this embodiment, a batch single-factor influence experiment is performed on the preparation conditions of the sulfur-modified biochar, and from the influences of the four factors, i.e., the secondary pyrolysis time, the secondary pyrolysis temperature, the original biochar preparation temperature, and the sulfur-carbon doping ratio, on the sulfur-modified biochar, the range of conditions for influencing the removal of heavy metal chromium is determined through the single-factor experiment in the research.

In this example, the biochar was prepared at 300 ℃ under the conditions of the secondary pyrolysis time, the secondary pyrolysis temperature was 700 ℃, and the sulfur-to-carbon ratio was 2: 1 is a fixed experimental condition, and the secondary pyrolysis time, namely the constant temperature holding time of the secondary pyrolysis of the biochar and the elemental sulfur is set to be 5, 10, 30, 60, 90 and 120min in sequence.

In this example, when the secondary pyrolysis temperature condition is set, the biochar is prepared at 450 ℃, the secondary pyrolysis time is 60min, and the sulfur-carbon ratio is 2: 1 is a fixed experimental condition, and the secondary pyrolysis temperature and the form conversion temperature are considered, namely the constant temperature keeping temperature of the secondary pyrolysis of the biochar and the elemental sulfur is 300 ℃, 400 ℃, 500 ℃ and 600 ℃ in sequence.

In this example, when the temperature conditions for preparing the raw biochar are set, the secondary pyrolysis temperature is 700 ℃, and the mass ratio of sulfur to carbon is 2: 1, the secondary pyrolysis time is 60min, and the original biochar with different temperatures is set to be 300-700 ℃ in sequence for fixed experimental conditions.

In this example, when the condition of the amount ratio of doped sulfur to carbon is set, biochar is prepared at 300 ℃, the secondary pyrolysis temperature is 450 ℃, the secondary pyrolysis time is 1h, and the fixed experimental conditions are set, and the mass ratio of sulfur to carbon is considered to be 0.25: 1. 0.5: 1. 1: 1. 2: 1. 3: 1.

FIG. 1 is a graph of the effect of secondary pyrolysis time on total chromium removal. The removal rate of the sulfur modified biochar in the solution gradually increases along with the increase of the secondary pyrolysis time, and reaches 72 percent at the maximum value at 60 min. In the control group, the prepared biochar is not doped with elemental sulfur, and is pyrolyzed again only at the modification time and modification temperature corresponding to the sulfur modified biochar. The removal rate of the experimental control group solution of the biochar without doping sulfur is 23 percent, and the change along with the time of secondary pyrolysis is not large.

FIG. 2 is a graph of the effect of secondary pyrolysis temperature on total chromium removal. When the temperature value of the secondary pyrolysis exceeds 450 ℃, the removal of chromium by the sulfur-modified biochar is obviously higher than that by the biochar of the control group, when the temperature is 500 ℃, the removal of chromium in the solution by the sulfur-modified biochar is basically kept unchanged and kept at 70%, and the removal of chromium by the biochar of the control group doped with sulfur is lower as the temperature is increased. The boiling point of sulfur is 444.6 ℃, and the removal rate is remarkably changed between 400 ℃ and 500 ℃, so that the secondary pyrolysis temperature of a response surface center experiment is determined to be 450 ℃.

FIG. 3 is a graph of the effect of raw biochar preparation temperature on total chromium removal. For the sulfur modified biochar, the change trend of the removal rate of heavy metal chromium is not obvious along with the increase of the preparation temperature of the original biochar; when the original biochar pyrolysis temperature exceeds 400 ℃, the total chromium removal rate shows a rapid rate reduction trend, and after the temperature reaches 600 ℃, the total chromium removal rate is basically kept at 25%. And for the control group of sulfur-undoped biochar, the removal rate of the original biochar at different temperatures in the solution is basically unchanged and is kept at 23 percent after the secondary pyrolysis at 700 ℃.

FIG. 4 is a graph of the effect of sulfur/carbon doping ratio on total chromium removal. With the increase of the ratio of the sulfur to the carbon, the removal rate of the sulfur modified biochar to chromium is gradually increased; when the sulfur/carbon ratio is too large (3:1), the removal rate of chromium by the modified biochar is reduced. In addition, after the undoped sulfur biochar prepared by pyrolyzing the 300 ℃ original biochar at 450 ℃ is physically mixed with elemental sulfur in a corresponding proportion, the effect of removing pollutants is not obviously different from that of simple biochar, and the elemental sulfur has no effect of removing heavy metal chromium.

Example 2

This embodiment is substantially the same as embodiment 1, and is characterized in that:

in this embodiment, according to the result of the single-factor test, the central point of the response surface is determined, and the response surface optimization test design is performed by selecting four factors of the secondary pyrolysis time a, the secondary pyrolysis temperature B, the doping ratios of the original biochar C and the sulfur carbon D at different temperatures, and the total chromium removal efficiency as response values, so as to optimize the sulfur-modified biochar process.

As can be seen from Table 1 and FIGS. 5(a) and 5(b), a significant level was reached when P < 0.05, where R is²The model explains that the model can explain the change level of 98.63% and the mismatch value is 0.0724 (0.9863)>0.05, not significant). Therefore, the model can be used to study and analyze the value of the predicted sulfur-modified carbon on the removal rate of chromium in solution. According to the model, when the secondary pyrolysis time is 60min, the secondary pyrolysis temperature is 450 ℃, the primary biochar temperature is 300 ℃, and the sulfur-carbon ratio is 2: 1, the removal rate of the sulfur modified biochar to the heavy metal chromium is up to 95 percent.

TABLE 1 regression model analysis for removal Rate

R＝0.993 R²＝0.9863 AdjR²＝0.9726 PredR²＝0.9256 Adeq Precision＝25.789

Example 3

This embodiment is substantially the same as the above embodiment, and is characterized in that:

in this example, in order to further understand the adsorption characteristics of sulfur-modified biochar on heavy metal chromium, the influence of solution pH on the removal of chromium from sulfur-modified biochar was studied, and the adsorption kinetics and adsorption isotherm experiments of sulfur-modified biochar on heavy metal chromium were performed.

FIG. 6 is a graph of the effect of initial solution pH on the removal of chromium from sulfur-modified biochar. As can be seen from the figure, the removal capacity of the sulfur-modified biochar on cr (vi) is reduced with the increase of the pH value, and at the same time, the reduction effect of the biochar on cr (vi) is also remarkably reduced. When the pH value of the solution containing Cr (VI) is increased from 2.0 to 10.0, the adsorption quantity of the sulfur modified biochar to the Cr (VI) is reduced from 45.1mg/g to 4.5 mg/g. It was found that the adsorption amount was maximized at pH 2.0, and the effect of removing cr (vi) was the best.

Fig. 7 is a graph of adsorption kinetics data of sulfur-modified biochar on cr (vi). Obtained by combining Table 2, R of the experimental data when fitting the same using a pseudo-second order model²>0.999, and the resulting R is fitted with a pseudo-first order kinetic model²>0.813 and an equilibrium adsorption capacity of 40.21mg/g as additionally fitted by pseudo-secondary kinetics.

TABLE 2 pseudo-first and second kinetic parameters of sulfur-modified biochar for Cr (VI) adsorption removal

FIG. 8 is a temperature contour diagram of adsorption of sulfur-modified biochar on Cr (VI). As can be seen from Table 3, the adsorption capacity of the sulfur-modified biochar to Cr (VI) is higher with the higher reaction temperature in both adsorption isothermal models, and the maximum adsorption amounts are 58.01mg/g and 60.8mg/g respectively. As can be seen from Table 3-2, the Freundlich adsorption isothermal model fitting coefficient R corresponds to 25 ℃, 30 ℃ and 35 ℃²0.93, 0.97 and 0.99 respectively, and the fitting coefficients of the Languuir adsorption isothermal model are 0.89, 0.94 and 0.93 respectively. Therefore, at different temperatures, the Freundlich adsorption isothermal model is more suitable for researching the adsorption process of the sulfur-modified biochar on Cr (VI) ions than the Languuir adsorption isothermal model, and the adsorption removal of the sulfur-modified biochar on Cr (VI) can be mainly carried out by multi-molecular-layer adsorption.

TABLE 3 adsorption fitting data of two isothermal models of sulfur-modified biochar to Cr (VI)

Example 4

This embodiment is substantially the same as the above embodiment, and is characterized in that:

in this example, in order to further determine whether sulfur is doped on the biochar in the sulfur-modified biochar, elemental analysis and SEM-EDS analysis were performed on the sulfur-modified biochar.

From the elemental analysis and SEM-EDS analysis in Table 4, the sulfur content was as low as 0.25% in the unmodified biochar, while the sulfur content was as much increased as 19.67% in the sulfur-modified biochar. And it is seen by SEM-EDS that sulfur was successfully integrated on the sulfur-modified biochar.

TABLE 4 elemental analysis of different biochar

FIG. 9 is an SEM-EDS image of sulfur-modified biochar and unmodified biochar. Wherein FIG. 9(a) is a scanning electron micrograph of unmodified biochar. Wherein, FIGS. 9(b), (c) and (d) are scanning electron micrographs of the sulfur-modified biochar. As can be seen by comparing the graphs (a) and (b), the irregular fiber structure of the surface of the unmodified biochar is extremely uneven, and the sulfur-modified biochar has a smoother surface structure due to the fact that part of substances, such as lignin and the like, can be carried away by sulfur on the surface of the sulfur-modified biochar material in the modification process. After high-temperature carbonization, a large number of holes are still reserved on the surface and inside of the generated sulfur-modified biochar material (figure (c)), and the pore structure is well developed, so that the subsequent full adsorption effect of the sulfur-modified biochar material is facilitated. And (d) shows that after the elemental sulfur and the biochar are pyrolyzed for the second time, the sulfur-modified biochar composite material is in a loose foam-like structure, which shows that the elemental sulfur is successfully loaded on the surface and in the pores of the sulfur-modified biochar material.

Fig. 9(e) shows the morphology and microscopic features of the sulfur-modified biochar composite, and the purpose of rapidly detecting the sulfur-modified biochar is achieved by performing morphology analysis on the sulfur-modified biochar B300S450-1-2 by using a scanning electron microscope and analyzing the elemental composition by using a combined energy spectrum. There are many fine particles on the outer surface of the "foam" (shown as the dashed arrow raised portion in fig. 9 (d)) and a large number of particles are trapped within the "channels" of the foam (shown as the solid arrow labeled portion). SEM-EDS scanning electron micrograph from the foam surface 9(e) shows that sulfur is distributed throughout the sulfur-modified biochar because we detected multiple particles on the biochar. Additionally, an accurate elemental content analysis of C, N, O, S was performed on this fraction, and it was determined that sulfur accounts for a significant proportion of C (58.02%) > O (27.28%) > S (8.80%) > N (5.91%). Therefore, the successful modification of the biochar by the sulfur can be further obtained, and a large amount of sulfur exists in the sulfur-modified biochar.

FIG. 10 is an XPS chart of before and after adsorption of sulfur-modified biochar and before and after modification. The C, O, S, Cr element full-spectrum analysis and the full-spectrum analysis before and after the sulfur modified biochar reaction can obtain that S is successfully integrated on the biochar, the sulfur peak is weakened after the reaction, and sulfur elements in the surface sulfur modified biochar play a certain role in removing heavy metal chromium.

In summary, in the above embodiment, the biochar is prepared by using the corn stalks as the raw material, the biochar is modified by using elemental sulfur, and the modified sulfur-containing biochar is used for removing cr (vi) ions in water. In the embodiment, the preparation conditions of the sulfur modified biochar are determined through a single-factor experiment and a response surface experiment; the system inspects the influence of the preparation temperature, the sulfur doping temperature, the solution pH value and the like of the sulfur modified biochar on the adsorption performance of Cr (VI), and researches the adsorption characteristic of the sulfur modified biochar by combining adsorption kinetics and an adsorption isotherm; by analyzing the sulfur modified biochar such as Element Analysis (EA), scanning electron microscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and the like and changing the physical and chemical characteristics of the biochar before and after adsorption, the ideal treatment effect for removing hexavalent chromium is expected to be achieved under the condition of low cost and simple operation.

The embodiments of the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the embodiments, and various changes and modifications can be made according to the purpose of the invention, and any changes, modifications, substitutions, combinations or simplifications made according to the spirit and principle of the technical solution of the present invention shall be equivalent substitutions, as long as the purpose of the present invention is met, and the present invention shall fall within the protection scope of the present invention without departing from the technical principle and inventive concept of the present invention.