An adsorbent, its preparation method and application

Abstract

This invention relates to the field of adsorbent technology, providing an adsorbent, its preparation method, and its applications. The method provided by this invention includes the following steps: mixing iron-based waste catalyst, oil sludge, and lignite to obtain a mixture; and subjecting the mixture to heat activation treatment to obtain the adsorbent. This invention uses two solid wastes, iron-based waste catalyst and oil sludge, as raw materials, reducing preparation costs. This invention utilizes the iron source in the iron-based waste catalyst as the main component of the adsorbent, while leveraging the binding properties of the oil sludge to allow the material obtained after heat activation treatment to be molded, eliminating the need for a later molding process. Furthermore, the high reactivity of lignite helps the adsorbent form an excellent pore structure during the heat activation treatment, improving its adsorption performance. The preparation method used in this invention is simple and easy to operate.

Description

Technical Field

[0001] This invention relates to the field of adsorbent technology, and in particular to an adsorbent, its preparation method, and its application. Background Technology

[0002] Water injection is a fundamental extraction method in oilfields. Due to differences in geological conditions, water injection characteristics, extraction methods, and technological conditions across oilfields, the quality of oilfield wastewater varies considerably. Sulfides are commonly found in oilfield produced water; therefore, the sulfide content in produced water is an important indicator of the degree of water pollution. The main form of sulfides in oilfield produced water is sulfur (S). 2- SO4 2- The presence of these substances can cause problems such as pipe corrosion, scaling, and the proliferation of sulfate-reducing bacteria (SRB).

[0003] Patent CN 112007615A discloses a method for preparing a composite adsorbent material for recovering organic dyes. This invention prepares an intermediate by reacting ferrocene selenide with titanium dioxide in a first reaction; the intermediate is then reacted with CuI in a second reaction to obtain the adsorbent material, which is then used for the treatment of light-controlled sulfur-containing dye wastewater. This composite adsorbent material can achieve the goals of environmental greening, energy saving and consumption reduction, time saving and high efficiency and resource regeneration. However, the method has a complex operation process and the raw materials used are expensive.

[0004] Patent CN 114405475A discloses an adsorbent material, its preparation method, and its application. This invention involves mixing a carbon source and an alkaline solution, then adding an iron source, and conducting a hydrothermal reaction to obtain an iron-based metal-organic framework material. The iron-based metal-organic framework material is then mixed with a solvent, and a reducing agent is slowly added, followed by ultrasonic treatment to obtain a magnetic and porous adsorbent material. This adsorbent material exhibits high adsorption capacity and easy recycling advantages when used for adsorbing pesticides such as glyphosate in water. While this preparation method can yield a porous magnetic adsorbent, it requires the use of expensive organometallic compounds and necessitates ultrasonic treatment during the preparation process, resulting in high production costs.

[0005] In summary, current methods for preparing adsorbents for advanced wastewater treatment suffer from high production costs and complex preparation processes, and there is a lack of adsorbent materials specifically designed for treating sulfur-containing wastewater from oil fields. Summary of the Invention

[0006] In view of this, the present invention provides an adsorbent, its preparation method, and its application. The raw materials used in the preparation of the present invention are mainly solid waste, which can reduce the preparation cost of the adsorbent and simplify the preparation process. At the same time, the prepared adsorbent is suitable for the treatment of sulfur-containing wastewater from oil fields.

[0007] To achieve the above-mentioned objective, the present invention provides a method for preparing an adsorbent, comprising the following steps:

[0008] Iron-based waste catalyst, oil sludge and lignite are mixed to obtain a mixture;

[0009] The mixture is heated and activated to obtain the adsorbent.

[0010] Preferably, the iron-based waste catalyst comprises iron and diatomaceous earth support; the mass fraction of iron in the iron-based waste catalyst is 30-50%, the mass fraction of diatomaceous earth support in the iron-based waste catalyst is 50-70%, and the oil-to-solid ratio in the oil sludge is 20-50:10-30.

[0011] Preferably, the total mass fraction of iron-based waste catalyst and oil sludge in the mixture is ≥70%, and the mass ratio of the iron-based waste catalyst to the oil sludge is 5-8:2-5.

[0012] Preferably, the temperature of the heating activation treatment is 800-1000℃, the time is 1-3h, and the activation gas used in the heating activation treatment is carbon dioxide or water vapor.

[0013] Preferably, the rate of heating to the temperature of the heat activation treatment is 3 to 50 °C / min.

[0014] Preferably, the particle size of the iron-based waste catalyst is ≤1mm, and the particle size of the lignite is ≤3mm.

[0015] The present invention also provides an adsorbent prepared by the preparation method described in the above technical solution.

[0016] Preferably, the adsorbent has a particle size of 3–20 mm and a specific surface area of ​​400–600 m². 2 / g, wherein the mass fraction of Fe2O3 in the adsorbent is 20-50%.

[0017] The present invention also provides the application of the adsorbent described in the above technical solution in the treatment of sulfur-containing wastewater.

[0018] Preferably, the sulfur-containing wastewater is oilfield sulfur-containing wastewater, the sulfur content in the sulfur-containing wastewater is greater than 0 mg / L and ≤500 mg / L, and the mass-volume ratio of the adsorbent to the sulfur-containing wastewater is 1 g: 1-5 L.

[0019] This invention provides a method for preparing an adsorbent, comprising the following steps: mixing iron-based waste catalyst, oil sludge, and lignite to obtain a mixture; and subjecting the mixture to heat activation treatment to obtain the adsorbent. This invention uses two solid wastes, iron-based waste catalyst and oil sludge, as raw materials, reducing preparation costs. This invention utilizes the iron source in the iron-based waste catalyst as the main component of the adsorbent, while leveraging the binding properties of the oil sludge to allow the material obtained after heat activation treatment to be molded, eliminating the need for a later molding process. Furthermore, the high reactivity of lignite helps the adsorbent form an excellent pore structure during the heat activation treatment, improving its adsorption performance. The preparation method used in this invention is simple and easy to operate.

[0020] This invention also provides an adsorbent prepared by the method described above. The adsorbent prepared by the method of this invention contains iron and has a large specific surface area, exhibiting good adsorption of sulfur in sulfur-containing wastewater. It also possesses magnetic properties, facilitating recovery.

[0021] This invention also provides the application of the adsorbent described above in the treatment of sulfur-containing wastewater. The adsorbent provided by this invention contains iron and has a large specific surface area, exhibiting good adsorption capacity for sulfur in sulfur-containing wastewater, and is suitable for treating sulfur-containing wastewater. Attached Figure Description

[0022] Figure 1 The image shows the pore size curve of the adsorbent prepared in Example 1. Detailed Implementation

[0023] This invention provides a method for preparing an adsorbent, comprising the following steps: mixing iron-based waste catalyst, oil sludge and lignite to obtain a mixture; and subjecting the mixture to a heating activation treatment to obtain the adsorbent.

[0024] Unless otherwise specified, all raw materials used in the preparation of this invention are commercially available.

[0025] This invention mixes iron-based waste catalyst, oil sludge, and lignite to obtain a mixture. In this invention, the iron-based waste catalyst is preferably a waste catalyst from the coal indirect liquefaction industry, and preferably comprises iron and a diatomaceous earth support. In this invention, the mass fraction of the diatomaceous earth support in the iron-based waste catalyst is preferably 50-70%, more preferably 55-70%, and even more preferably 55-65%, and the mass fraction of iron in the iron-based waste catalyst is preferably 30-50%, more preferably 40-50%, and even more preferably 45-50%. In this invention, the particle size of the iron-based waste catalyst is preferably ≤1 mm, and even more preferably 0.125-1 mm. In this invention, the iron-based waste catalyst is preferably purchased from Shenhua Ningxia Coal Industry Group. In this invention, the oil-to-solid ratio in the oil sludge is preferably 20-50:10-30, more preferably 30-50:10-20, and even more preferably 40-50:10-15. In this invention, the oil sludge preferably also includes water, and the water content of the oil sludge is preferably 30-50%, more preferably 35-45%. In a specific embodiment of this invention, the oil sludge is preferably dried oil sludge from the Shengli Oilfield, the drying temperature is preferably 90-110℃, more preferably 95-105℃, and even more preferably 100℃, and the drying time is preferably 20-26h, more preferably 23-25h, and even more preferably 24h. In this invention, the mass ratio of the iron-based waste catalyst to the oil sludge is preferably 5-8:2-5, more preferably 6-8:2-4, and even more preferably 7-8:2-3. In this invention, the total mass fraction of the iron-based waste catalyst and oil sludge in the mixture is preferably ≥70%, more preferably 70-80%, and even more preferably 70-85%. In this invention, the particle size of the lignite is preferably ≤3mm, more preferably 0.5-1mm. In this invention, the mixing method is preferably stirring. The present invention does not have specific requirements for the stirring speed and time, as long as there is no dry powder or particles in the mixture.

[0026] After obtaining the mixture, the present invention subjectes the mixture to a heating activation treatment to obtain the adsorbent. In the present invention, the temperature of the heating activation treatment is preferably 800–1000°C, more preferably 800–900°C, and even more preferably 800–850°C; the time of the heating activation treatment is preferably 1–3 h, more preferably 1–2 h, and even more preferably 1–1.5 h. In the present invention, the temperature and time of the heating activation treatment affect the specific surface area of ​​the adsorbent. The present invention limits the activation temperature and time to within the above ranges to prepare an adsorbent with a high specific surface area. In the present invention, the rate of heating to the temperature of the heating activation treatment is preferably 3–50°C / min, more preferably 3–20°C / min, and even more preferably 3–10°C / min. In the present invention, the activation gas used in the heating activation treatment is preferably carbon dioxide or water vapor, more preferably carbon dioxide. In this invention, the gas flow rate for the heating activation treatment is preferably 500–1000 mL / min, more preferably 600–900 mL / min, and even more preferably 800 mL / min. This invention preferably uses heating activation treatment to convert iron in iron-based waste catalysts into ferric oxide (Fe₂O₃). Ferric oxide can convert sulfur in sulfur-containing wastewater... -2 Oxidation into elemental sulfur facilitates solid-liquid separation; oil sludge produces a substance similar to asphalt, and lignite produces a substance similar to activated carbon, increasing the specific surface area of ​​the adsorbent. In addition, this invention preferably softens and melts the oil sludge by adjusting the heating rate, allowing it to flow and disperse fully among other raw materials, which can play a role in bonding and shaping and controlling the particle size of the adsorbent. Furthermore, the specific surface area of ​​the adsorbent is increased by introducing a specific type of gas to create pores in the adsorbent.

[0027] The present invention also provides an adsorbent prepared by the preparation method described in the above technical solution. In the present invention, the particle size of the adsorbent is preferably 3–20 mm, more preferably 5–15 mm, and even more preferably 5–10 mm. In the present invention, the specific surface area of ​​the adsorbent is preferably 400–600 m². 2 / g, more preferably 450-600m 2 / g, further preferably 500-600m 2 / g. In this invention, the mass fraction of Fe2O3 in the adsorbent is preferably 20-50%, more preferably 30-50%, and even more preferably 30-40%.

[0028] This invention also provides the application of the adsorbent described above in the treatment of sulfur-containing wastewater. In this invention, the application preferably includes the following steps: mixing the adsorbent and sulfur-containing wastewater for adsorption. In this invention, the sulfur-containing wastewater is preferably oilfield sulfur-containing wastewater, and the sulfur content in the sulfur-containing wastewater is preferably greater than 0 mg / L and ≤500 mg / L, more preferably 40–300 mg / L, and even more preferably 50–100 mg / L. In this invention, the mass ratio of the adsorbent to the volume of the sulfur-containing wastewater is preferably 1 g: 1–5 L, more preferably 1 g: 1–4.5 L, and even more preferably 1 g: 1–4 L. In this invention, the adsorption temperature is preferably 25–60 °C, more preferably 40–60 °C.

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments thereof.

[0030] Example 1

[0031] Iron-based waste catalyst, oil sludge, and lignite were mixed evenly. The iron-based waste catalyst was purchased from Shenhua Ningxia Coal Industry Group and is a waste catalyst from the coal indirect liquefaction industry. The iron-based waste catalyst has a mass fraction of 35% iron and 65% diatomaceous earth carrier, with an average particle size of 0.3 mm. The oil sludge has an oil-to-solid ratio of 45:15 and comes from Shengli Oilfield. It was dried at 100℃ for 24 hours. The total mass of the iron-based waste catalyst and the dried oil sludge accounts for 70% of the total mass of the mixture. The average particle size of the lignite is 1 mm. The mass ratio of iron-based waste catalyst to oil sludge is 7:3.

[0032] The mixture was transferred to an alumina crucible, which was then placed in a horizontal tube furnace. Activation was performed under a CO2 atmosphere at a heating rate of 3°C / min to 800°C. The CO2 flow rate was 800 mL / min, and the activation time was 90 min. The mixture was then allowed to cool naturally to room temperature. The adsorbent was then screened using a porous sieve to obtain adsorbent with a particle size of 3 mm or larger.

[0033] The specific surface area of ​​the adsorbent was determined to be 578 m² using the nitrogen adsorption method. 2 / g. Figure 1 The image shows the pore size profile of the adsorbent prepared in Example 1. Figure 1 It can be seen that the pore size of the adsorbent prepared in Example 1 is mainly concentrated between 2 and 4 nm, which belongs to mesoporous materials. Furthermore, the adsorbent prepared in Example 1 has a large specific surface area, which is beneficial to improving the adsorption of sulfur in sulfur-containing wastewater.

[0034] Example 2

[0035] The total mass fraction of iron-based waste catalyst and oil sludge in the mixture was adjusted to 75%, and the mass ratio of iron-based waste catalyst to oil sludge was adjusted to 6:4. The heating rate was adjusted to 5℃ / min, and the activation temperature was adjusted to 850℃. The remaining conditions were the same as in Example 1, and an adsorbent with a particle size of more than 3mm was obtained.

[0036] The specific surface area of ​​the adsorbent was determined to be 388 m² using the nitrogen adsorption method. 2 / g.

[0037] Example 3

[0038] The mass ratio of iron-based waste catalyst to oil sludge was adjusted to 6.5:3.5; the heating rate was adjusted to 10℃ / min; the activation temperature was adjusted to 850℃; the activation time was 60min; and the remaining conditions were the same as in Example 1, resulting in an adsorbent with a particle size of more than 3mm.

[0039] The specific surface area of ​​the adsorbent, measured using the nitrogen adsorption method, was 298 m². 2 / g.

[0040] Example 4

[0041] The mass ratio of iron-based waste catalyst to oil sludge was adjusted to 5:5; the heating rate was adjusted to 25℃ / min; the activation temperature was adjusted to 900℃; the activation time was 3h; the activation treatment was carried out under the condition of introducing water vapor at a rate of 1000mL / min; the remaining conditions were the same as in Example 1, and an adsorbent with a particle size of more than 3mm was obtained.

[0042] The specific surface area of ​​the adsorbent, measured using the nitrogen adsorption method, was 403 m². 2 / g.

[0043] Example 5

[0044] The mass fraction of iron-based waste catalyst and oil sludge in the total mass of the mixture was adjusted to 80%, and the mass ratio of iron-based waste catalyst to oil sludge was adjusted to 8:2. The heating rate was adjusted to 50℃ / min, the activation temperature was adjusted to 1000℃, the activation time was 1h, and the activation treatment was carried out under the condition of introducing water vapor at a rate of 1000mL / min. The remaining conditions were the same as in Example 1, and an adsorbent with a particle size of 3mm or more was obtained.

[0045] The specific surface area of ​​the adsorbent was determined to be 365 m² using the nitrogen adsorption method. 2 / g.

[0046] Comparative Example 1

[0047] The activation temperature was adjusted to 750°C, and the other conditions were the same as in Example 1, resulting in an adsorbent with a particle size of 3 mm or more.

[0048] The specific surface area of ​​the adsorbent was determined to be 353 m² using the nitrogen adsorption method. 2 / g.

[0049] Comparative Example 2

[0050] The heating rate was adjusted to 60℃ / min, and the other conditions were the same as in Example 1, resulting in an adsorbent with a particle size of 3 mm or more.

[0051] The specific surface area of ​​the adsorbent was determined to be 382 m² using the nitrogen adsorption method. 2 / g.

[0052] Comparative Example 3

[0053] The heating rate was adjusted to 0.5℃ / min, and the other conditions were the same as in Example 1, resulting in an adsorbent with a particle size of 3 mm or more.

[0054] The specific surface area of ​​the adsorbent was determined to be 399 m² using the nitrogen adsorption method. 2 / g.

[0055] Comparative Example 4

[0056] Commercially available diatomaceous earth adsorbent was used as a comparative example.

[0057] Comparative Example 5

[0058] Commercially available activated carbon adsorbents were used as a comparative example.

[0059] Comparative Example 6

[0060] Commercially available zinc oxide adsorbent was used as a comparative example.

[0061] Comparative Example 7

[0062] Commercially available zeolite adsorbents were used as a comparative example.

[0063] Application Example 1

[0064] The adsorbents prepared in Examples 1-3 and the adsorbents in Comparative Examples 1-7 were used as adsorbent samples to treat sulfur-containing wastewater, where the sulfur was mainly S. 2-A 20×200mm (DN=18mm) U-shaped tube with branch pipes was used as the reactor for the adsorption experiment. The U-shape was 40mm wide, and both sides of the tube included branch pipes with a diameter of 7mm. The height of the branch pipes from the lowest point of the U-shape was 200mm. Adsorbent was filled into the U-shaped tube with branch pipes. Sulfur-containing wastewater was introduced using a peristaltic pump through one branch pipe as the inlet. After adsorption treatment by the adsorbent in the U-shaped tube, the wastewater flowed out through the other branch pipe as the outlet. 1.0g of adsorbent sample was filled to the side near the outlet, and the remaining portion was filled with 5mm diameter glass beads, with a mass of 14.0g. The filling height of the adsorbent sample and glass beads was the same. The adsorption temperature was room temperature. The sulfur content (S) in the sulfur-containing wastewater before treatment was measured using a DR3900 visible spectrophotometer. 2- The concentration of sulfur in the treated wastewater was determined by adjusting the flow rate and residence time of the sulfur-containing wastewater. A DR3900 visible spectrophotometer was used to measure the sulfur content at different residence times. 2- The concentration of S in the treated wastewater was calculated. 2- The concentration of sulfur in the wastewater before treatment 2- The difference in concentration is calculated by dividing this difference by the S concentration in the sulfur-containing wastewater before treatment. 2- The concentration was used to calculate the sulfur removal rate of the adsorbent. Table 1 shows the sulfur removal results of the adsorbents prepared in Examples 1-5 and Comparative Examples 1-7 at different residence times.

[0065] Table 1. Desulfurization results of the adsorbents in Examples 1-5 and Comparative Examples 1-7 at different residence times.

[0066]

[0067]

[0068] As shown in Table 1, this invention selects iron-based waste catalyst, oil sludge, and lignite as raw materials and performs heating activation treatment under specific conditions to obtain an adsorbent with good adsorption performance. The adsorbent prepared by this invention has high adsorption performance, but it is prepared from solid waste, thus reducing preparation costs while achieving resource utilization of waste.

[0069] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An application of an adsorbent in the treatment of sulfur-containing wastewater, characterized in that, The method for preparing the adsorbent includes the following steps: Iron-based waste catalyst, oil sludge, and lignite are mixed to obtain a mixture; the iron-based waste catalyst is a waste catalyst from the coal indirect liquefaction industry; the total mass fraction of the iron-based waste catalyst and oil sludge in the mixture is ≥70%, and the mass ratio of the iron-based waste catalyst to the oil sludge is 5~8:2~5; the iron-based waste catalyst includes iron and diatomaceous earth support; the mass fraction of iron in the iron-based waste catalyst is 30~50%, and the mass fraction of the diatomaceous earth support in the iron-based waste catalyst is 50~70%; the oil-to-solid ratio in the oil sludge is 20~50:10~30; The mixture is subjected to heating activation treatment to obtain the adsorbent; the heating activation treatment temperature is 800~1000℃, the time is 1~3h, and the activation gas used in the heating activation treatment is carbon dioxide or water vapor.

2. The application according to claim 1, characterized in that, The rate of heating to the temperature of the heat activation treatment is 3~50℃ / min.

3. The application according to claim 1, characterized in that, The iron-based waste catalyst has a particle size ≤1mm, and the lignite has a particle size ≤3mm.

4. The application according to claim 1, characterized in that, The adsorbent has a particle size of 3-20 mm and a specific surface area of ​​400-600 m². 2 / g, wherein the mass fraction of Fe2O3 in the adsorbent is 20~50%.

5. The application according to claim 1, characterized in that, The sulfur-containing wastewater is oilfield sulfur-containing wastewater, and the sulfur content in the sulfur-containing wastewater is greater than 0 mg / L and ≤500 mg / L. The mass-volume ratio of the adsorbent to the sulfur-containing wastewater is 1 g: 1~5 L.

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