CN107552036A - A kind of photocatalyst compound material RHC CS/La3+‑TiO2Preparation method - Google Patents

Abstract

The invention relates to a preparation method of a photocatalyst composite material RHC-CS/La ³⁺ -TiO ₂ and its application in treating benzene series solubilized wastewater. The preparation method of the photocatalyst composite material, the steps are as follows: (1) chemical etching of rice husk charcoal RHC; (2) loading carbon spheres on rice husk charcoal to obtain RHC-CS; (3) impregnating RHC-CS in titanium source The precursor is used to obtain the photocatalyst composite material RHC‑CS/La ³⁺ ‑TiO ₂ through a sol-gel-hydrothermal method. The composite material prepared by the present invention has a good selective adsorption and degradation effect, and can effectively degrade benzene series solubilized wastewater with a concentration of 1000 mg/L within 12 hours, wherein the removal rates of toluene, benzene and chlorobenzene respectively reach 87 %, 82% and 85%, while the surfactant concentration remained basically unchanged during the degradation process. The preparation process is simple, cost-effective, green and safe, and the prepared material has stable properties and good environmental friendliness. It has good application prospects in the treatment of benzene series solubilized wastewater, and can also be extended to the field of soil remediation.

Description

A kind of preparation method of photocatalyst composite material RHC-CS/La3+-TiO2

technical field

The invention belongs to the field of organic waste water treatment, relates to the treatment of benzene series solubilized organic waste water, and is a preparation method of a photocatalyst composite material RHC-CS/La ³⁺ -TiO ₂ .

Background technique

Organic compound wastewater is widely produced in many industries such as chemical plants, pharmaceutical plants, and tanneries, as well as in the leakage of liquid hazardous chemicals. Benzene series is a kind of highly toxic and refractory organic matter, which has a wide range of sources, a large amount, and great harm. The large amount of waste water discharges seriously pollutes the environment, which not only endangers agricultural production, animal and plant growth and reproduction, but also threatens human health.

In the wastewater produced by rinsing and extraction processes, there are a large amount of surfactants, and the hydrophobic structure provided by surfactant micelles will greatly increase the solubility of organic pollutants in aqueous solution, which will lead to the degradation of organic pollutants by surfactants. Solubilized benzene series wastewater is more difficult to degrade. Therefore, the treatment of benzene series wastewater solubilized by surfactants has always been a concern in water treatment research.

At present, photocatalytic reactions using semiconductor oxides (TiO ₂ , ZnO, Fe ₂ O ₃ , SnO ₂ , WO ₃ , etc.) as photocatalysts have attracted great attention. However, pure photocatalysts have various disadvantages that lead to their low photocatalytic efficiency. According to the principle of photocatalytic regeneration, the adsorption material and photocatalyst are combined to treat organic compound wastewater, and the photocatalytic activity of the photocatalyst is combined with the adsorption performance of the adsorption material. On the one hand, the adsorption capacity of the adsorbent is enhanced; on the other hand, The adsorption capacity of the adsorbent provides a high concentration for the photocatalytic reaction, improves the photocatalytic reaction rate, and adsorbs the by-products of the reaction to completely purify the pollutants.

For the treatment of benzene series wastewater solubilized by surfactants, the adsorption treatment technology is combined with photocatalytic technology, and the influence of surfactant micelles is taken into account. The composite material needs to have the function of selective adsorption, so that the benzene series The destabilization of micelles on the surface of objects can achieve the purpose of rapid adsorption and degradation, thus effectively making up for the shortcomings of existing photocatalytic technologies in degrading micelles and solubilizing organic compounds.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing a dual-functional micro-region photocatalyst composite material RHC-CS/La ³⁺ -TiO ₂ , the hydrophobic micro-region of the composite material can anchor the surfactant in an orientation, and make the micelles Destabilization and degradation micro-regions can adsorb free benzene series molecules and promote their photocatalytic degradation.

A kind of preparation method of photocatalyst composite material RHC-CS/La ³⁺ -TiO ₂ , the steps are as follows:

(1) Chemical etching of rice husk charcoal: sieve rice husk charcoal, carbonize it, then immerse it in 1-3mol/L KOH solution for 10-15h, filter, and wash until the pH is 6-7, then the rice husk The shell charcoal is dried at a temperature of 100-110 degrees Celsius for 1-3 hours, cooled, and finally under the protection of nitrogen, the temperature is raised to 500-700 degrees Celsius at a heating rate of 3-10 degrees Celsius/min and activated for 10-30 minutes. Cool to room temperature to obtain the product.

(2) Load carbon microspheres on rice husk charcoal: add the rice husk charcoal treated in step (1) to glucose or sodium hydroxymethylcellulose or a mixed solution of glucose and sodium hydroxymethylcellulose, and ultrasonically disperse After 10 to 20 minutes, react with water at 160 to 240 degrees Celsius for 3 to 6 hours, cool to room temperature naturally, wash with distilled water and ethanol for 3 to 5 times, and finally dry the RHC-CS for 1 to 3 hours at a temperature of 100 to 110 degrees Celsius.

(3) RHC-CS is impregnated in the titanium source precursor, and the photocatalyst composite material is obtained by sol-gel-hydrothermal method: add a certain amount of nitric acid-dissolved lanthanum oxide and glacial acetic acid to the titanium source precursor, in which lanthanum oxide The addition amount of the mixture is 0% to 1%, and then add the RHC-CS treated in step (2), wherein the addition amount of the RHC-CS is 5% to 20%, stir for 10 to 20 minutes, and then dropwise add anhydrous The mixture of ethanol and deionized water, and adjust the pH to 1~2, continue to stir for 90~120 minutes after the dropwise addition, let it stand for 15~20 hours to form a gel, and hydrothermally react at 120~240 degrees Celsius for 1~4 After cooling to room temperature, wash with distilled water and ethanol until neutral, dry at 100-110 degrees Celsius for 1-3 hours, and then heat up to 100 degrees Celsius at a rate of 10-20 degrees Celsius/minute in a tube furnace. ～300℃, constant temperature for 1～2 hours to remove volatile matter, then raise the temperature to 500～600℃ and calcinate for 2～4 hours to obtain RHC-CS/La ³⁺ -TiO ₂ .

Moreover, in the step (2), the concentration of glucose or sodium hydroxymethylcellulose or the mixed solution of glucose and sodium hydroxymethylcellulose is 0.5 mol/L.

Moreover, in the step (3), the titanium source precursor is tetrabutyl titanate or isopropyl titanate or titanium tetrachloride or titanium sulfate or titanyl sulfate.

Moreover, in the step (3), the amount of RHC-CS added to the titanium source precursor is 5% to 20%.

Moreover, in the step (3), the addition amount of lanthanum oxide in the titanium source precursor is 0.1%-1%.

Moreover, in the step (3), the mixed droplet velocity of absolute ethanol and deionized water is 1Drop/s.

Moreover, in the step (3), the gel time of the composite material is 18h.

Moreover, in the step (3), the pH regulator is hydrochloric acid with a mass fraction of 37%.

Advantages and beneficial effects of the present invention:

1. The prepared composite material has a good selective adsorption and degradation effect, and can effectively degrade benzene series solubilization wastewater with a concentration of 1000mg/L within 12 hours, and the removal rate of toluene, benzene and chlorobenzene Respectively reach 87%, 82% and 85%, while the surfactant concentration remains basically unchanged during the degradation process, which does not affect the recovery and application of the surfactant.

2. During the surface etching process of rice husk charcoal, by controlling the concentration of activator, activation temperature and activation time, the control of carbon pore structure is realized. The concentration of activator directly affects the specific surface area and pore volume of carbon materials, and the long-term activation Time favors the formation of micropores and mesopores, and high temperature favors the formation of mesopores.

3. The final calcination temperature of the composite material affects its crystal form. As the calcination temperature increases, the TiO ₂ crystal form will gradually change from anatase to rutile. Anatase TiO ₂ has a better Photocatalytic degradation effect.

4. An appropriate amount of lanthanum oxide doping can distort the lattice structure of the prepared composite material and change the interplanar spacing, and at the same time inhibit the growth of titanium dioxide grains, which is conducive to the improvement of photocatalytic performance and can also expand TiO2. ₂ spectral response range.

5. The preparation process of the present invention is simple to operate, economical and efficient, green and safe.

6. The material prepared by the present invention has stable properties and good environmental friendliness. It has good application prospects in the treatment of benzene series solubilized wastewater, and can also be extended to the field of soil restoration.

Description of drawings

Fig. 1(a), Fig. 1(b) and Fig. 1(c) are SEM images of RHC, RHC-CS and RHC-CS/La ³⁺ -TiO ₂ of the present invention, respectively.

Fig. 2 is the XRD pattern of RHC-CS/La ³⁺ -TiO ₂ of the present invention.

Fig. 3(a), Fig. 3(b) and Fig. 3(c) are contact angle diagrams of RHC, RHC-CS and RHC-CS/La ³⁺ -TiO ₂ of the present invention, respectively.

Fig. 4 is a graph showing the degradation curve of toluene in the process of RHC-CS/La ³⁺ -TiO ₂ photocatalytic degradation of toluene solubilized wastewater according to the present invention.

Fig. 5 is the degradation curve of TX-100 in the process of photocatalytic degradation of toluene solubilized wastewater by RHC-CS/La ³⁺ -TiO ₂ (Example 3) of the present invention.

Fig. 6 is a graph showing the degradation curve of benzene during the photocatalytic degradation of benzene solubilized wastewater by RHC-CS/La ³⁺ -TiO ₂ of the present invention.

Fig. 7 is the degradation curve of chlorobenzene in the process of RHC-CS/La ³⁺ -TiO ₂ photocatalytic degradation of chlorobenzene solubilized wastewater according to the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Example 1

(1) Preparation of RHC

Sieve the rice husk charcoal, carbonize it, then soak it in 1.5mol/L KOH solution for 10h, filter, and wash until the pH is 6.77, then dry the rice husk charcoal at 105 degrees Celsius for 2 hours, cool it, and finally put it under nitrogen protection At a heating rate of 4 degrees Celsius/minute, the product was activated at 400 degrees Celsius and kept at a temperature of 30 minutes, and then naturally cooled to room temperature to obtain the product.

(2) Preparation of RHC-CS

Get 0.35 g of rice husk charcoal in step (1), and add it into 30 mL of glucose solution whose concentration is 0.5 mol/L. After ultrasonic dispersion for 10 minutes, hydrothermal reaction at 180°C for 5 hours, natural cooling to room temperature, washing with distilled water and ethanol for 4 times, and finally drying RHC-CS for 2 hours at 105°C.

(3) Preparation of RHC-CS/La ³⁺ -TiO ₂ composites

Dissolve 35mL of butyl titanate in 70mL of absolute ethanol, then add 2mL of lanthanum oxide dissolved in nitric acid, wherein the mass of lanthanum oxide is 0.05g, then add 23mL of glacial acetic acid and 0.4g of the RHC- Stir the CS for 10 minutes, then add 80 mL of a mixture of absolute ethanol and deionized water at a rate of 1 Drop/s under vigorous stirring, wherein the volume ratio of absolute ethanol to deionized water is 1:1, and adjust the pH to 2 After the dropwise addition was completed, the mixture was stirred for 100 minutes, and left to stand to form a gel for 18 hours. Hydrothermal reaction at 180°C for 3 hours, cooled to room temperature, washed with distilled water and ethanol until neutral, dried at 105°C for 2 hours, then heated to 300°C at 10°C/min in a tube furnace, Keep the temperature at constant temperature for 1 hour to remove volatile matter, then raise the temperature to 650 degrees Celsius and calcinate for 2 hours to obtain RHC-CS/La ³⁺ -TiO ₂ .

As shown in FIG. 1 , it is the SEM spectrum of the three materials RHC, RHC-CS and RHC-CS/La ³⁺ -TiO ₂ prepared in steps (1), (2) and (3) of the present invention. It can be seen from the figure that RHC has a rich pore structure; the carbon spheres generated by glucose after hydrothermal treatment are mainly concentrated on the surface of RHC and the large pores, and the size of carbon spheres is 2-5 microns; RHC-CS/La ³ The surface of ⁺ -TiO ₂ material supports a lot of titanium dioxide particles.

As shown in Fig. 2, it is the XRD spectrum of the RHC-CS/La ³⁺ -TiO ₂ composite material prepared in (3) of the present invention. It can be seen from the figure that the crystal form of the composite material is anatase.

As shown in FIG. 3 , it is the contact angle spectrum of the three materials RHC, RHC-CS and RHC-CS/La ³⁺ -TiO ₂ prepared in steps (1), (2) and (3) of the present invention. It can be seen from the figure that the order of the contact angles of the three materials is RHC>RHC-CS>RHC-CS/La ³⁺ -TiO ₂ , and the material changes from a hydrophobic interface to a hydrophilic interface, which also preliminarily proves that the prepared Photocatalyst of composite material RHC-CS/La ³⁺ -TiO ₂ .

Example 2

(1) Preparation of RHC

The rice husk charcoal was sieved, carbonized, then soaked in 2mol/L KOH solution for 10h, filtered, and washed until the pH was 6.89, then the rice husk charcoal was dried at 100 degrees Celsius for 3 hours, cooled, and finally under nitrogen protection , heated at a heating rate of 4 degrees Celsius/min to 500 degrees Celsius for activation and kept for 20 minutes, and naturally cooled to room temperature to obtain the product.

(2) Preparation of RHC-CS

Get 0.375 g of rice husk charcoal in step (1), and add it into 30 mL of 0.5 mol/L sodium hydroxymethyl cellulose solution. After ultrasonic dispersion for 10 minutes, hydrothermal reaction at 200 degrees Celsius for 4 hours, natural cooling to room temperature, washing with distilled water and ethanol for 5 times, and finally drying RHC-CS for 2 hours at 100 degrees Celsius.

(3) Preparation of RHC-CS/La ³⁺ -TiO ₂ composites

Dissolve 35mL of butyl titanate in 80mL of absolute ethanol, then add 2mL of lanthanum oxide dissolved in nitric acid, wherein the mass of lanthanum oxide is 0.03g, then add 23mL of glacial acetic acid and 0.8g of the RHC- CS, stirred for 10 minutes, then added 90 mL of a mixture of absolute ethanol and deionized water at a rate of 1 Drop/s under vigorous stirring, wherein the volume ratio of absolute ethanol and deionized water was 1:1, and adjusted the pH to 2. Continue to stir for 100 minutes after the dropwise addition, and let stand to form a gel for 18 hours. Hydrothermal reaction at 200 degrees Celsius for 2 hours, cooled to room temperature, washed with distilled water and ethanol until neutral, dried at 100 degrees Celsius for 3 hours, and then heated to 200 degrees Celsius at 10 degrees Celsius/minute in a tube furnace, Keep the temperature at constant temperature for 1 hour to remove volatile matter, and then raise the temperature to 700 degrees Celsius for 1 hour and calcinate for 1 hour to obtain RHC-CS/La ³⁺ -TiO ₂ .

Example 3

(1) Preparation of RHC

Sieve the rice husk charcoal, carbonize it, then impregnate it in 2.5mol/L KOH solution for 12h, filter, and wash until the pH is 6.85, then dry the rice husk charcoal at 110 degrees Celsius for 2 hours, cool it, and finally put it under nitrogen protection At a heating rate of 4 degrees Celsius/minute, the product was activated at 450 degrees Celsius and kept at a temperature of 20 minutes, and then naturally cooled to room temperature to obtain the product.

(2) Preparation of RHC-CS

Get 0.5 g of rice husk charcoal in step (1), and add it into 30 mL of a mixed solution of glucose and sodium hydroxymethyl cellulose with a concentration of 0.5 mol/L. After ultrasonic dispersion for 10 minutes, hydrothermal reaction at 220 degrees Celsius for 3 hours, natural cooling to room temperature, washing with distilled water and ethanol for 4 times, and finally drying RHC-CS for 2 hours at 110 degrees Celsius.

(3) Preparation of RHC-CS/La ³⁺ -TiO ₂ composites

Dissolve 35mL of butyl titanate in 85mL of absolute ethanol, then add 2mL of lanthanum oxide dissolved in nitric acid, wherein the mass of lanthanum oxide is 0.08g, then add 23mL of glacial acetic acid and 0.6g of the RHC- CS, stirred for 10 minutes, then added 85 mL of a mixture of absolute ethanol and deionized water at a rate of 1 Drop/s under vigorous stirring, wherein the volume ratio of absolute ethanol and deionized water was 1:1, and adjusted the pH to 2. Continue to stir for 120 minutes after the dropwise addition, and let stand to form a gel for 18 hours. Hydrothermal reaction at 220 degrees Celsius for 2 hours, cooled to room temperature, washed with distilled water and ethanol until neutral, dried at 110 degrees Celsius for 1 hour, then heated to 250 degrees Celsius at 10 degrees Celsius/minute in a tube furnace, Keep the temperature at constant temperature for 1 hour to remove volatile matter, then raise the temperature to 550 degrees Celsius and calcinate for 2 hours to obtain RHC-CS/La ³⁺ -TiO ₂ .

Application example 1

Add 1000 mg/L toluene to the TX-100 solution with a concentration of 0.2 mM (cmc value), and after stirring evenly, add 1 g of the composite materials in Example 1, Example 2 and Example 3 respectively. Before using ultraviolet radiation, put the suspension into dark field for dark adsorption for 1h. After dark adsorption, use a 100W ultraviolet lamp to irradiate the suspension for 12 hours at a distance of 20 cm from the sample, and inject air into the upper part to supplement dissolved oxygen and stir. In the process of radiation, samples are taken at regular intervals, and the residual amount of toluene is measured. After testing, the maximum removal rate of toluene in 12 hours reaches about 87%, while the removal rate of TX-100 in the degradation process of the composite material in Example 3 is only 4%, indicating that the composite material can undergo selective adsorption degradation.

Application example 2

Add 1000mg/L of benzene to the TX-100 solution with a concentration of 0.2mM (cmc value), and after stirring evenly, add 1g of the composite materials in Example 1, Example 2 and Example 3 respectively. Before using ultraviolet radiation, put the suspension into dark field for dark adsorption for 1h. After dark adsorption, use a 100W ultraviolet lamp to irradiate the suspension for 12 hours at a distance of 20 cm from the sample, and inject air into the upper part to supplement dissolved oxygen and stir. During the radiation process, samples were taken at regular intervals to measure the residual amount of benzene. It was tested that the maximum removal rate of benzene reached about 82% within 12 hours.

Application example 3

Add 1000mg/L of chlorobenzene to the TX-100 solution with a concentration of 0.2mM (cmc value), and after stirring evenly, add 1g of the composite materials in Example 1, Example 2 and Example 3 respectively. Before using ultraviolet radiation, put the suspension into dark field for dark adsorption for 1h. After dark adsorption, use a 100W ultraviolet lamp to irradiate the suspension for 12 hours at a distance of 20 cm from the sample, and inject air into the upper part to supplement dissolved oxygen and stir. During the radiation process, samples were taken at regular intervals to measure the residual amount of chlorobenzene. After testing, the maximum removal rate of chlorobenzene reached about 85% within 12 hours.

Comparative example 1

Add 1000 mg/L toluene to the TX-100 solution with a concentration of 0.2 mM (cmc value), stir evenly, and then add 1 g of RHC-CS in step (2). Before using ultraviolet radiation, put the suspension into dark field for dark adsorption for 1h. After dark adsorption, use a 100W ultraviolet lamp to irradiate the suspension for 12 hours at a distance of 20 cm from the sample, and inject air into the upper part to supplement dissolved oxygen and stir. During the radiation process, samples were taken at regular intervals to measure the residual amount of toluene. It was detected that the removal rate of toluene was only 20% within 12 hours.

Comparative example 2

Add 1000mg/L toluene to the TX-100 solution with a concentration of 0.2mM (cmc value), stir well, then add 1g of P25. Before using ultraviolet radiation, put the suspension into dark field for dark adsorption for 1h. After dark adsorption, use a 100W ultraviolet lamp to irradiate the suspension for 12 hours at a distance of 20 cm from the sample, and inject air into the upper part to supplement dissolved oxygen and stir. During the radiation process, samples were taken at regular intervals to measure the residual amount of toluene. It was detected that the removal rate of toluene within 12 hours was only 46%.

Comparative example 3

Add 1000 mg/L benzene to the TX-100 solution with a concentration of 0.2 mM (cmc value), stir well, then add 1 g of RHC-CS in step (2). Before using ultraviolet radiation, put the suspension into dark field for dark adsorption for 1h. After dark adsorption, use a 100W ultraviolet lamp to irradiate the suspension for 12 hours at a distance of 20 cm from the sample, and inject air into the upper part to supplement dissolved oxygen and stir. During the radiation process, samples were taken at regular intervals to measure the residual amount of benzene. It was detected that the removal rate of benzene was only 20% within 12 hours.

Comparative example 4

Add 1000 mg/L benzene to the TX-100 solution with a concentration of 0.2 mM (cmc value), stir well, then add 1 g of P25. Before using ultraviolet radiation, put the suspension into dark field for dark adsorption for 1h. After dark adsorption, use a 100W ultraviolet lamp to irradiate the suspension for 12 hours at a distance of 20 cm from the sample, and inject air into the upper part to supplement dissolved oxygen and stir. During the radiation process, samples were taken at regular intervals to measure the residual amount of benzene. It was detected that the removal rate of benzene within 12 hours was only 48%.

Comparative example 5

Add 1000 mg/L chlorobenzene to the TX-100 solution with a concentration of 0.2 mM (cmc value), and after stirring evenly, add 1 g of RHC-CS in step (2). Before using ultraviolet radiation, put the suspension into dark field for dark adsorption for 1h. After dark adsorption, use a 100W ultraviolet lamp to irradiate the suspension for 12 hours at a distance of 20 cm from the sample, and inject air into the upper part to supplement dissolved oxygen and stir. During the radiation process, samples were taken at regular intervals to measure the residual amount of chlorobenzene, and the removal rate of chlorobenzene was only 21% within 12 hours after testing.

Comparative example 6

Add 1000mg/L chlorobenzene to the TX-100 solution with a concentration of 0.2mM (cmc value), stir well, then add 1g of P25. Before using ultraviolet radiation, put the suspension into dark field for dark adsorption for 1h. After dark adsorption, use a 100W ultraviolet lamp to irradiate the suspension for 12 hours at a distance of 20 cm from the sample, and inject air into the upper part to supplement dissolved oxygen and stir. During the radiation process, samples were taken at regular intervals to measure the residual amount of chlorobenzene, and the removal rate of chlorobenzene was only 48% within 12 hours after detection.

Claims (7)

1. A preparation method of photocatalyst composite material RHC-CS/La ³⁺ -TiO ₂ , the steps are as follows: (1) chemical etching of rice husk charcoal RHC; (2) loading carbon spheres RHC- on rice husk charcoal CS; (3) The photocatalyst composite material RHC-CS/La ³⁺ -TiO ₂ was obtained by impregnating RHC-CS in the titanium source precursor through sol-gel-hydrothermal method. 2. photocatalyst composite material RHC-CS/La according to claim 1 ³⁺ -TiO ₂ preparation method, it is characterized in that: described step (1) is that rice husk charcoal is sieved, carbonized, then in 1 Immerse in ~3mol/L KOH solution for 10~15h, filter, and wash until the pH value is 6~7, then dry the rice husk charcoal at a temperature of 100~110 degrees Celsius for 1~3 hours, cool, and finally under nitrogen protection , at a heating rate of 3-10 degrees Celsius/minute to 500-700 degrees Celsius for activation and heat preservation for 10-30 minutes, and naturally cooled to room temperature to obtain the product. 3. The preparation method of photocatalyst composite material RHC-CS/La ³⁺ -TiO ₂ according to claim 1, characterized in that: said step (2) is to add rice husk charcoal after step (1) treatment Add glucose or sodium hydroxymethyl cellulose or a mixed solution of glucose and sodium hydroxymethyl cellulose, ultrasonically disperse for 10 to 20 minutes, react with water at 160 to 240 degrees Celsius for 3 to 6 hours, and cool to room temperature naturally Wash with distilled water and ethanol for 3 to 5 times, and finally dry the RHC-CS for 1 to 3 hours at a temperature of 100 to 110 degrees Celsius. 4. The preparation method of photocatalyst composite material RHC-CS/La ³⁺ -TiO ₂ according to claim 1, characterized in that: said step (3) is to add a certain amount of nitric acid to the titanium source precursor to dissolve lanthanum oxide and glacial acetic acid, then add the RHC-CS treated in step (2), stir for 10 to 20 minutes, then add dropwise the mixed solution of absolute ethanol and deionized water, and adjust the pH value to 1~ 2. Continue to stir for 90-120 minutes after the dropwise addition, let it stand for 15-20 hours to form a gel, react with hydrothermal reaction at 160-240 degrees Celsius for 1-4 hours, cool to room temperature, wash with distilled water and ethanol until neutral, Dry at a temperature of 100-110 degrees Celsius for 1-3 hours, then heat up to 100-300 degrees Celsius in a tube furnace at a rate of 10-20 degrees Celsius/minute, keep the temperature for 1-2 hours to remove volatiles, and then heat up to Calcined at 500-600°C for 2-4 hours to obtain RHC-CS/La ³⁺ -TiO ₂ . 5. The photocatalyst composite material RHC-CS/La ³⁺ -TiO according to claim ₃ The preparation method is characterized in that: the mixing of glucose or sodium hydroxymethyl cellulose or glucose and sodium hydroxymethyl cellulose The concentration of the solution is 0.5mol/L. 6. The preparation method of the photocatalyst composite material RHC-CS/La ³⁺ -TiO ₂ according to claim 4, characterized in that: the addition amount of RHC-CS in the titanium source precursor is 5-20%. 7. The preparation method of the photocatalyst composite material RHC-CS/La ³⁺ -TiO ₂ according to claim 4, characterized in that the addition amount of lanthanum oxide in the titanium source precursor is 0.1-1%.