WO2018209875A1

WO2018209875A1 - Algae-removing coagulant for enhancing algae coagulation and degrading algae-containing sediment in visible light simultaneously, preparation method therefor and application thereof

Info

Publication number: WO2018209875A1
Application number: PCT/CN2017/104483
Authority: WO
Inventors: 裴海燕; 金岩; 张莎莎
Original assignee: 山东大学
Priority date: 2017-05-18
Filing date: 2017-09-29
Publication date: 2018-11-22
Also published as: AU2017414754B2; AU2017414754A1; CN107098453A; CN107098453B

Abstract

An algae-removing coagulant for enhancing algae coagulation and degrading algae-containing sediment in visible light simultaneously, comprising the following component in part by weight: 50-400 parts of N-TiO2 powder and 7.5 parts of polyaluminum ferric chloride. Also disclosed are a preparation method and application of the algae-removing coagulant for enhancing algae coagulation and degrading algae-containing sediment in visible light simultaneously.

Description

Algae-removing coagulant for strengthening algae coagulation and degrading algae-containing mud under visible light, preparation method and application thereof

Technical field

The invention relates to the field of drinking water treatment, in particular to a de-algae coagulant for strengthening algae coagulation and degrading algae-containing mud under visible light, and a preparation method and application thereof.

Background technique

In recent years, the eutrophication of freshwater lakes in China has become increasingly serious, and algae have proliferated in large quantities, forming water blooms, which seriously affect the quality of raw water. The large-scale reproduction of algae changes the physical and chemical environment of the water body, the transparency is reduced, the water body emits odor and the dissolved oxygen is reduced, which not only affects the aquaculture water ecosystem, water supply, tourism and ecological landscape, but also seriously interferes with the normal life of human beings.

In the drinking water process, the removal of algae mainly depends on the coagulation process. However, since the algae have a certain floating property, the flocs produced thereof are not easy to settle, thereby reducing the removal efficiency of the algae and increasing the burden of the subsequent treatment process. In addition, there are some harmful algae, such as Microcystisaeruginosa, which settle into the algae cells in the sediment, which can release microcystins and affect human health. When discharging muddy water containing algal toxins, it will cause secondary pollution of the water body. Therefore, how to strengthen the algae coagulation, enhance the algae removal efficiency and effectively degrade the algae-containing mud, so that the muddy water is harmlessly discharged is an urgent problem to be solved.

Summary of the invention

The technical problem to be solved by the present invention is to provide a de-algae coagulant which can improve the efficiency of coagulation and algae removal, and can degrade the algae-containing mud under the visible light and make the muddy water harmlessly discharged.

In order to solve the above technical problem, the present invention provides the following technical solutions:

According to a first aspect of the present invention, there is provided a algaecide coagulant for inhibiting algae coagulation while degrading algae-containing mud under visible light, which is composed of the following parts by weight: 50-400 parts by weight of N-TiO ₂ powder, 7.5 parts by weight of polyaluminum ferric chloride.

Wherein, the N-TiO ₂ powder is prepared by the following method: 12-18 parts by weight of butyl titanate, 18-22 parts by weight of absolute ethanol, 0.05-0.5 parts by weight of urea and 28-35 weight The diluted dilute nitric acid solution is heated at 80 to 100 ° C for 3 to 5 hours, and then calcined at 400 ° C to 500 ° C for 3 to 5 hours, and the obtained white powder is N-TiO ₂ .

According to a second aspect of the present invention, there is provided a method for preparing the above-mentioned algaecide coagulant, wherein the N-TiO ₂ powder and the polyaluminum ferric chloride are weighed according to a set weight, and the algae coagulant is obtained after being uniformly mixed.

According to a third aspect of the present invention, there is provided a use of the above algaecide coagulant for degrading algae-containing coagulum while degrading algae-containing mud under visible light.

Compared with the prior art, the present invention has the following beneficial effects:

In the present invention, the algaecide coagulant is compounded with N-TiO ₂ powder and polyaluminum ferric chloride, and the amount of the polyaluminum ferric chloride coagulant used alone is reduced by 50%, which significantly reduces the mixing. The amount of coagulant used increases the algae removal efficiency. In addition, the N-TiO ₂ powder has little impact on the environment and does not cause secondary pollution to the water body. The reduction of the amount of the coagulant also reduces the content of heavy metals in the water body, avoids heavy metal pollution, and further improves the water quality. After the coagulation is completed, the N-TiO ₂ powder settles into the sediment with the algae-containing floc, and the algae-containing mud is subjected to visible light irradiation while stirring, and all algae can be degraded and destroyed in 12 hours, and the algae released in the algae within 48 hours. The degradation rate of toxins is over 85%. Reduced sediment volume and improved muddy water quality for safe discharge or further recycling.

DRAWINGS

The accompanying drawings, which are incorporated in the claims of the claims

Figure 1 shows the effect of different doses of PAFC on algae removal.

Figure 2 shows the algae removal rate of the coagulant formulated with PAFC and PAFC and different concentrations of N-TiO ₂ powder during coagulation.

Figure 3 shows the algae removal rate of floc sedimentation process of coagulant formulated with PAFC and PAFC and different concentrations of N-TiO ₂ powder.

Figure 4 shows the changes of chlorophyll in different concentrations of N-TiO ₂ powder during degradation of algae-containing mud under visible light.

Figure 5 shows the changes of microcystins (MCs) during the degradation of algae-containing sludge under visible light with different concentrations of N-TiO ₂ powder.

detailed description

It should be noted that the following detailed description is illustrative and is intended to provide a further description of the invention. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise indicated.

It is to be noted that the terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the exemplary embodiments of the invention. As used herein, the singular " " " " " " There are features, steps, operations, and/or combinations thereof.

The materials, reagents and the like used in the present invention are commercially available unless otherwise specified.

In the present invention, the algae removal rate, the algal cell degradation rate, and the microcapsule toxin (MCs) degradation rate are calculated as follows:

Algae removal rate (%) = (experimental water source OD ₆₈₀ - supernatant OD ₆₈₀ ) × 100% / experimental water source OD ₆₈₀ ;

Algae cell degradation rate (%) = (0h contains algae sediment chlorophyll content - measured time point contains algae sediment chlorophyll content) × 100% / 0h containing algae sediment chlorophyll content;

Microcystins degradation rate (%) = (microcystin content in the complete rupture of algae cells in algae sediments - microcystin content in algae sediment at the time point measured) × 100% / algae-containing sediment Microcystin content when the algae cells are completely ruptured.

As described in the background art, there are certain deficiencies in the method for removing algae in the drinking water process, and at the same time, harmful substances released by some algae cannot be effectively degraded. In order to solve the above technical problems, the first aspect of the present invention provides a The algae-containing coagulant which refines algae coagulation while degrading the algae-containing mud under visible light is composed of the following parts by weight: 50 to 400 parts by weight of N-TiO ₂ powder, and 7.5 parts by weight of polyaluminum ferric chloride.

In a preferred embodiment of the present invention, the above-mentioned algaecide coagulant is composed of the following parts by weight: 200 to 250 parts by weight of N-TiO ₂ powder, and 7.5 parts by weight of polyaluminum ferric chloride.

In a most preferred embodiment of the present invention, the above-described algaecide coagulant is composed of the following parts by weight: 200 parts by weight of N-TiO ₂ powder, and 7.5 parts by weight of polyaluminum ferric chloride.

In terms of improving the algae removal rate and degrading the algae-containing sludge, in a preferred embodiment of the present invention, the N-TiO ₂ powder is prepared by the following method:

15 parts by weight of butyl titanate is added to 20 parts by weight of absolute ethanol, stirred to obtain a solution A;

0.05 to 0.5 parts by weight of urea is added to 30 parts by weight of dilute nitric acid solution, mixed to form solution B;

Under stirring, the solution A was slowly added to the solution B, the pH was adjusted to 7 with a sodium hydroxide solution, and heated at 80 ° C for 3 hours;

Thereafter, the supernatant was centrifuged, the precipitate was washed with water three times, and calcined at 400 ° C to 500 ° C for 3 hours to obtain a white powder of N-TiO ₂ .

In a preferred embodiment of the present invention, the N-TiO ₂ powder has a particle diameter of 50 to 150 mesh; more preferably, the N-TiO ₂ powder has a particle diameter of 100 mesh.

According to a second aspect of the present invention, a method for preparing the above-mentioned algaecide coagulant is provided, wherein N-TiO ₂ powder and polyaluminum ferric chloride are weighed according to a set weight, and the algae coagulant is obtained after being uniformly mixed. .

The specific application form may include the following steps:

Step (1): adding the above-mentioned algaecide coagulant to the algae-containing water to stir to complete coagulation;

Step (2): after standing to precipitate, the algae-containing floc is sedimented to the bottom, and the algae in the supernatant is removed;

Step (3): discard the supernatant, leave the bottom containing algae sediment, place it under visible light and stir it for a certain period of time. After (12 to 48 h), algae and algal toxins were degraded.

Wherein, in the step (1), the density of the algae-containing water is 10 ⁵ to 10 ⁷ cells/mL, the stirring condition is 150 to 250 rpm, stirring for 1 to 2 minutes, and stirring at 30 to 60 rpm for 10 to 20 minutes.

The dose of coagulant PAFC was 7.5 mg/L for a semi-optimal dose (15 mg/L without N-TiO ₂ ) and 50-400 mg/L for N-TiO ₂ . The PAFC and N-TiO _{2 are} put into the algae-containing water and rapidly stirred to rapidly disperse to form fine scented flowers. At this time, the water body becomes more turbid, so that the water flow can generate intense turbulence, and in the flocculation stage, the process of sputum flower grows thicker. Appropriate turbulence and sufficient residence time (10-20 min) are required. At the later stage, a large amount of alfalfa accumulation can be observed to rely on gravity to sink slowly. During the coagulation process, the OD ₆₈₀ value of the supernatant (2 cm below the liquid surface) was measured, and the sedimentation of the flocs during the coagulation process was investigated.

Wherein, in the step (2), the rest time is 10 to 60 min. In the sedimentation stage, a large number of coarse alfalfa flowers are deposited, and the upper layer of water is clarified water. The remaining small-sized and low-density alfalfa flowers slowly descend while continuing to collide with each other, and the residual turbidity remains basically unchanged. The OD ₆₈₀ value of the supernatant turbidity during the sedimentation process was determined, and the time required for complete flotation of the flocs was examined.

Algae cells in water usually have a large number, a small specific gravity, and a high negative charge on the surface, which is difficult to remove. In addition, the flocs formed by the algae cells have a certain floating property, making it difficult to settle and reducing the algae removal efficiency. Polyaluminum ferric chloride is a highly efficient inorganic polymer coagulant. When an appropriate amount of N-TiO ₂ powder is added during the coagulation process, N-TiO ₂ can be used as a micro-floc produced by the coagulant. The core, combined with the polyaluminum ferric chloride, utilizes the sediment trapping mechanism, electric neutralization and bridging to make the algae cells formed by coagulation rapid and rapid sedimentation, and the effect of removing algae is good.

Wherein, in the step (3), the discarded supernatant liquid accounts for 93% to 97% of the total volume, the light intensity is 3000 to 15000 Lux, and the stirring speed is 200 to 800 rpm.

TiO ₂ semiconductors have become the most widely used photocatalysts due to their non-toxicity, low cost, stable performance and corrosion resistance. However, from the viewpoint of its photocatalytic efficiency, the titanium dioxide photocatalyst has some limitations: due to its band gap of 3.2 eV, narrow light absorption band (mainly in the ultraviolet region), low solar light utilization efficiency; semiconductor carrier High compounding rate and low quantum efficiency. The introduction of the non-metallic element N can enlarge the photo-response range of TiO ₂ , thereby increasing its photocatalytic activity in the visible light region. Therefore, N-TiO ₂ can efficiently degrade algae, algal toxins, and intracellular extracellular organisms under visible light.

When the initial algae concentration is 10 ⁵ ~ 10 ⁷ cells / mL, the dosage of N-TiO ₂ powder is 50 ~ 400mg / L, and the mixed dosage of polyaluminium ferric chloride is 7.5mg / L of semi-optimal dose (not added The optimal dosage of N-TiO ₂ is 15mg/L), the algae removal rate can reach over 96%, and the algae removal rate is good. In the process of degrading algae-containing sediment, all the algae were degraded and ruptured within 12 hours. Within 48 hours, the degradation rate of algae released by algae reached more than 85%.

In order to enable those skilled in the art to more clearly understand the technical solutions of the present invention, the technical solutions of the present invention will be described in detail below in conjunction with specific embodiments and comparative examples.

Example 1

The algaecide coagulant is composed of the following parts by weight: 50 parts by weight of N-TiO ₂ powder (particle size of 100 mesh) and 7.5 parts by weight of polyaluminum ferric chloride.

The Microcystisaeruginosa used in the experiment was cultured in BG11 medium at a temperature of 25 ° C for 12 hours, dark for 12 hours, and light intensity of 2000 lux, and cultured to a logarithmic growth stage for preparation of an experimental algae-containing water source.

Dilute the concentration of the algae solution to 1×10 ⁶ cells/mL with deionized water, and prepare the experimental water source. The volume of the treated water sample is 1L, and weigh 50mg of N-TiO ₂ powder and 7.5mg of polyaluminum chloride. In each liter of experimental water source, stir at 250 rpm for 1 min, and slowly stir at 30 rpm for 30 min to complete the coagulation process. The supernatant at 2 cm below the liquid surface was taken within 2 h after the coagulation process and coagulation, and the absorbance at 680 nm (OD ₆₈₀ ) was measured. The algae removal rate reached the maximum 1 h after the completion of coagulation. , for 96%. See Figures 2 and 3.

After the algae-containing floc settles, the supernatant is discarded, and the remaining part is the algae-containing mud, which accounts for about 7% of the original volume. The algae-containing mud was placed under visible light of 8000 lux and stirred at 500 rpm. After 48 hours, 41.6% of the algae cells were degraded, and some microcystins were also present in the algae cells. See Figures 4 and 5.

Example 2

The algaecide coagulant is composed of the following parts by weight: 100 parts by weight of N-TiO ₂ powder (particle size of 100 mesh) and 7.5 parts by weight of polyaluminum ferric chloride.

Dilute the concentration of the algae solution to 1×10 ⁶ cells/mL with deionized water, and prepare the experimental water source. The volume of the treated water sample is 1L, and weigh 100mg of N-TiO ₂ powder and 7.5mg of polyaluminum chloride. In each liter of experimental water source, stir at 250 rpm for 1 min, and slowly stir at 30 rpm for 30 min to complete the coagulation process. The supernatant at 2 cm below the liquid surface was taken within 2 h after the coagulation process and coagulation, and the absorbance at 680 nm (OD ₆₈₀ ) was measured. The algae removal rate reached the maximum 1 h after the completion of coagulation. , for 97%. See Figures 2 and 3.

After the algae-containing floc settles, the supernatant is discarded, and the remaining part is the algae-containing mud, which accounts for about 7% of the original volume. The algae-containing mud was placed under visible light of 8000 lux and stirred at 500 rpm. After 48 hours, 59.9% of the algae cells were degraded, and some microcystins were also present in the algae cells. See Figures 4 and 5.

Example 3

The algaecide coagulant is composed of the following parts by weight: 200 parts by weight of N-TiO ₂ powder (particle size of 100 mesh) and 7.5 parts by weight of polyaluminum ferric chloride.

The Microcystisaeruginosa used in the experiment was cultured in BG11 medium at a temperature of 25 ° C. Illumination for 12 hours, darkness for 12 hours, light intensity of 2000 lux, culture to logarithmic growth stage, for the preparation of experimental algae-containing water source.

Dilute the concentration of the algae solution to 1×10 ⁶ cells/mL with deionized water, and prepare the experimental water source. The volume of the treated water sample is 1L, and weigh 200mg of N-TiO ₂ powder and 7.5mg of polyaluminium chloride. In each liter of experimental water source, stir at 250 rpm for 1 min, and slowly stir at 30 rpm for 30 min to complete the coagulation process. The supernatant at 2 cm below the liquid surface was taken within 2 h after the coagulation process and coagulation, and the absorbance at 680 nm (OD ₆₈₀ ) was measured. The algae removal rate reached the maximum 10 min after the coagulation was completed. , for 98%. See Figures 2 and 3.

After the algae-containing floc settles, the supernatant is discarded, and the remaining part is the algae-containing mud, which accounts for about 7% of the original volume. The algae-containing mud was placed under visible light of 8000 lux and stirred at 500 rpm. After 12 hours, all algae cells were degraded, and the degradation rate of microcystins was 84.2% after 48 hours. See Figures 4 and 5.

Example 4

The algaecide coagulant is composed of the following parts by weight: 400 parts by weight of N-TiO ₂ powder (particle size of 100 mesh) and 7.5 parts by weight of polyaluminum ferric chloride.

Dilute the concentration of the algae solution to 1×10 ⁶ cells/mL with deionized water, and prepare the experimental water source. The volume of the treated water sample is 1L, and weigh 400 mg of N-TiO ₂ powder and 7.5 mg of polyaluminium chloride. In each liter of experimental water source, stir at 250 rpm for 1 min, and slowly stir at 30 rpm for 30 min to complete the coagulation process. The supernatant at 2 cm below the liquid surface was taken within 2 h after the coagulation process and coagulation, and the absorbance at 680 nm (OD ₆₈₀ ) was measured. The algae removal rate reached the maximum 10 min after the coagulation was completed. , for 98%. See Figures 2 and 3.

After the algae-containing floc settles, the supernatant is discarded, and the remaining part is the algae-containing mud, which accounts for about 7% of the original volume. The algae-containing mud was placed under visible light of 8000 lux and stirred at 500 rpm. After 12 hours, all algae cells were degraded, and the degradation rate of microcystins was 87.6% after 48 hours. See Figures 4 and 5.

In Examples 1 to 4, the algaecide coagulant in Example 3 is preferred. In Example 1 and Example 2, the algae in the sediment did not completely degrade within 48 hours, and the treatment effect was not achieved. In Example 4, the amount of the N-TiO ₂ powder added was too large, and part of the N-TiO ₂ powder remained in the supernatant after the completion of the coagulation, which affected the water quality and increased the treatment cost.

In the face of "how to strengthen algae coagulation, enhance the efficiency of algae removal, reduce the amount of conventional coagulant, and at the same time effectively degrade the algae-containing mud", the present invention uses "photocatalyst and conventional coagulant to strengthen each other. The basic idea of algae coagulation and degradation of algae-containing mud under visible light, and screening and optimization of raw materials and raw material ratio under this idea. For the kind of photocatalyst, the inventors have selected a nitrogen-doped TiO ₂ photocatalyst after screening optimization, because it has been found that TiO ₂ is doped with nitrogen after titanium doping compared to other metal or non-metal doped TiO ₂ . According to this characteristic, it can be used as the core of the micro-flocs generated by the coagulant breaking. The polyaluminium chloride is beneficial to the dispersion of coagulant and the formation of flocs, which enhances the flocculation effect. It can solve the phenomenon of floating flowers in a short time; in addition, nitrogen-doped TiO ₂ degrades algae, algal toxins and intracellular extracellular organisms under visible light. For the screening of coagulants, in view of the characteristics of algae, this application prefers polyaluminum ferric chloride, which combines the advantages of aluminum and iron salts, and has a significant improvement in the morphology of aluminum ions and iron ions. Improve; interact with nitrogen-doped TiO ₂ to maximize the effect of treating algae-containing water; and for the amount of choice, 7.5 parts by weight of polyaluminum ferric chloride is preferred, when the amount of N-TiO ₂ is certain (the treatment effect is the best, When the amount is the lowest, when the amount is more than 7.5 parts by weight of the aluminum ferric chloride, the algae removal rate will decrease; when less than 7.5 parts by weight of the polyaluminum ferric chloride, regardless of the amount of N-TiO ₂ , the treatment The effect could not be optimized, and a combination of 7.5 parts by weight of polyaluminum ferric chloride and 50 to 400 parts by weight of N-TiO ₂ powder was selected.

When studying the effects of various raw materials and raw material ratios on the treatment of algae-containing water bodies, it was found that the effects of different raw material combinations on the treatment of algae-containing water bodies were significantly different. Only the comparative examples 1 to 5 were used as examples, but the research was done. Not limited to the following comparative examples.

Comparative example 1

The algaecide coagulant consists of the following parts by weight: 7.5 parts by weight of polyaluminum ferric chloride.

The concentration of the algae solution was diluted to 1×10 ⁶ cells/mL with deionized water to prepare an experimental water source. The volume of the treated water sample was 1 L, and 7.5 mg of polyaluminium ferric chloride was weighed and mixed into each experimental water source, 250 rpm. Stir for 1 min, stir slowly at 30 rpm for 30 min to complete the coagulation process. The supernatant at 2 cm below the liquid surface was taken within 2 h after the coagulation process and coagulation, and the absorbance at 680 nm (OD ₆₈₀ ) was measured. The algae removal rate is shown in Fig. 2 and Fig. 3. 2 available, the flocculation rate is slow, the algae removal rate in the coagulation process is low, only 5 to 6%, which can be obtained from Fig. 3, the algae removal rate is only about 60% at 120 min during the flocculation sedimentation process, at 120 min. The algae removal rate reached a maximum of only 80%.

After the algae-containing floc settles, the supernatant is discarded, and the remaining part is the algae-containing mud, which accounts for about 7% of the original volume. The algae-containing mud was placed under visible light of 8000 lux and stirred at 500 rpm. The degradation rate of algae cells is shown in Fig. 4. The change of microcystins is shown in Fig. 5, and the contents of chlorophyll and microcystins are not changed much.

When PAFC is used alone, the removal effect of algae is shown in Fig. 1. As shown in Fig. 1, when the dose of PAFC is 7.5 mg/L, the algae removal rate is only about 60%, and when the PAFC dose is 15 mg/ L, the algae removal rate reached the maximum, 90%.

Comparative example 2

The algaecide coagulant is composed of the following parts by weight: 200 parts by weight of N-TiO ₂ powder (particle size of 100 mesh) and 7.5 parts by weight of polymeric aluminum aluminum silicate.

Dilute the concentration of the algae solution to 1×10 ⁶ cells/mL with deionized water, and prepare the experimental water source. The volume of the treated water sample is 1L, and weigh 200mg of N-TiO ₂ powder and 7.5mg of polyaluminium chloride. In each liter of experimental water source, stir at 250 rpm for 1 min, and slowly stir at 30 rpm for 30 min to complete the coagulation process. The supernatant at 2 cm below the liquid surface was taken within 2 h after the coagulation process and the completion of coagulation, and the absorbance at the wavelength of ₆₈₀ nm (OD ₆₈₀ ) was measured. During flocculation, the algae removal rate can reach 80% at 30 min.

Comparative example 3

The algaecide coagulant is composed of the following parts by weight: 200 parts by weight of TiO ₂ powder (particle size of 100 mesh) and 7.5 parts by weight of polyaluminum ferric chloride.

Dilute the concentration of the algae solution to 1×10 ⁶ cells/mL with deionized water, and prepare the experimental water source. The volume of the treated water sample is 1L, and weigh 200mg of N-TiO ₂ powder and 7.5mg of polyaluminium chloride. In each liter of experimental water source, stir at 250 rpm for 1 min, and slowly stir at 30 rpm for 30 min to complete the coagulation process. The supernatant at 2 cm below the liquid surface was taken within 2 h after the coagulation process and the completion of coagulation, and the absorbance at the wavelength of ₆₈₀ nm (OD ₆₈₀ ) was measured. During flocculation, the algae removal rate can reach 85% at 30 min.

After the algae-containing floc settles, the supernatant is discarded, and the remaining part is the algae-containing mud, which accounts for about 7% of the original volume. The algae-containing sludge was placed under irradiation with 8000 lux of visible light while stirring at 500 rpm. After 48h, only 49% of the algae cells were degraded, and the degradation rate of microcystins after 48h was only 48.4%.

Comparative example 4

The algaecide coagulant consists of the following parts by weight: 200 parts by weight of rare earth doped TiO ₂ powder (particle size 100 mesh) and 7.5 parts by weight of polymeric aluminum aluminum silicate.

Among them, the rare earth doped TiO ₂ powder is prepared by the following method:

Take 20ml of absolute ethanol, then add butyl titanate, stir for 2h, then add the rare earth cerium nitrate solution to hydrolyze, continue to stir vigorously until the gel is formed, take out and dry, and calcine in a muffle furnace at 400 °C for 5h to obtain rare earth doping. Mixed TiO ₂ powder.

Dilute the concentration of the algae solution to 1×10 ⁶ cells/mL with deionized water, and prepare the experimental water source. The volume of the treated water sample is 1L, and weigh 200mg of N-TiO ₂ powder and 7.5mg of polyaluminium chloride. In each liter of experimental water source, stir at 250 rpm for 1 min, and slowly stir at 30 rpm for 30 min to complete the coagulation process. The supernatant at 2 cm below the liquid surface was taken within 2 h after the coagulation process and the completion of coagulation, and the absorbance at the wavelength of ₆₈₀ nm (OD ₆₈₀ ) was measured. During flocculation, the algae removal rate reached 83% at 30 min.

After the algae-containing floc settles, the supernatant is discarded, and the remaining part is the algae-containing mud, which accounts for about 7% of the original volume. The algae-containing sludge was placed under irradiation with 8000 lux of visible light while stirring at 500 rpm. After 48h, only 43% of the algae cells were degraded, and the degradation rate of microcystins after 48h was only 45.6%.

Comparative example 5

The algaecide coagulant is composed of the following parts by weight: 200 parts by weight of N-TiO ₂ powder (particle size of 100 mesh) and 10 parts by weight of polyaluminum ferric chloride.

Dilute the concentration of the algae solution to 1×10 ⁶ cells/mL with deionized water, and prepare the experimental water source. The volume of the treated water sample is 1L, and weigh 200mg of N-TiO ₂ powder and 7.5mg of polyaluminium chloride. In each liter of experimental water source, stir at 250 rpm for 1 min, and slowly stir at 30 rpm for 30 min to complete the coagulation process. The supernatant at 2 cm below the liquid surface was taken within 2 h after the coagulation process and the completion of coagulation, and the absorbance at the wavelength of ₆₈₀ nm (OD ₆₈₀ ) was measured. During flocculation, the algae removal rate can reach 90% at 30 min.

In summary, the algaecide coagulant provided by the present invention is compounded with PAFC and N-TiO ₂ powder, and the amount of coagulant is reduced by 50% compared with the single coagulant or other coagulant, and the water is remarkably lowered. The treatment cost, and the algae removal efficiency is more than 96%, the effect is significantly higher than the comparative examples 1 to 5, wherein the N-TiO ₂ powder has little impact on the environment and does not cause secondary pollution to the water body. After the coagulation is completed, the N-TiO ₂ powder settles into the sediment with the algae-containing floc, and the algae-containing mud is subjected to visible light irradiation while stirring, and at the appropriate N-TiO ₂ dose, all algae can be degraded and broken within 12 hours. And the degradation rate of algae released from algae reached more than 85% within 48h, and the effect was significantly higher than that of the comparative examples 1-5. Reduced sediment volume and improved muddy water quality for safe discharge or further recycling. In addition, the amount of each component in the algaecide-containing coagulant of the present invention is also very critical. The inventors adjusted the amount of the raw materials during the test, and found that the algae removal of the algaecide-containing coagulant after the adjusted amount was adjusted. The rate and degradation of the algae-containing mud is significantly reduced.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and combinations thereof may be made without departing from the spirit and scope of the invention. Simplifications should all be equivalent replacements and are included in the scope of the present invention.

Claims

An algaecide coagulant for strengthening algae coagulation and degrading algae-containing mud under visible light, characterized in that it is composed of the following parts by weight: 50-400 parts by weight of N-TiO 2 powder, 7.5 parts by weight of polymerized chlorine Aluminum iron.
The algaecide-containing coagulant according to claim 1, which is composed of the following parts by weight: 200 to 250 parts by weight of N-TiO 2 powder, and 7.5 parts by weight of polyaluminum ferric chloride.
The algaecide-containing coagulant according to claim 2, which is composed of the following parts by weight: 200 parts by weight of N-TiO 2 powder, and 7.5 parts by weight of polyaluminum ferric chloride.
The algaecide-containing coagulant according to claim 1, wherein the N-TiO 2 powder is obtained by the following method: 12 to 18 parts by weight of butyl titanate, and 18 to 22 parts by weight of no Water ethanol, 0.05 to 0.5 parts by weight of urea and 28 to 35 parts by weight of a dilute nitric acid solution are heated at 80 to 100 ° C for 3 to 5 hours, and then calcined at 400 to 500 ° C for 3 to 5 hours to obtain a white powder. That is N-TiO 2 .
The algaecide-containing coagulant according to claim 4, wherein the N-TiO 2 powder is prepared by the following method:

15 parts by weight of butyl titanate is added to 20 parts by weight of absolute ethanol, stirred to obtain a solution A;

0.05 to 0.5 parts by weight of urea is added to 30 parts by weight of dilute nitric acid solution, mixed to form solution B;

Under stirring, the solution A was slowly added to the solution B, the pH was adjusted to 7 with a sodium hydroxide solution, and heated at 80 ° C for 3 hours;

Thereafter, the supernatant was centrifuged, the precipitate was washed with water three times, and calcined at 400 ° C to 500 ° C for 3 hours to obtain a white powder of N-TiO 2 .
The algaecide-containing coagulant according to claim 1, wherein the N-TiO 2 powder has a particle diameter of 50 to 150 mesh.
The algaecide-containing coagulant according to claim 6, wherein the N-TiO 2 powder has a particle diameter of 100 mesh.
The method for preparing a algaecide coagulant according to any one of claims 1 to 7, wherein the N-TiO 2 powder and the polyaluminum ferric chloride are weighed according to the set weight, and the mixture is uniformly mixed. Algae coagulant.
The algaecide-containing coagulant according to any one of claims 1 to 7 for use in a method of fortifying algae coagulation while degrading algae-containing sludge under visible light.
The use according to claim 9, wherein the concentration of the polyaluminum ferric chloride contained in the algae-containing water is 7.5 mg/L when the initial algae concentration is 10 5 to 10 7 cells/mL; and the algae-containing water contains The concentration of N-TiO 2 is 50 to 400 mg/L.