WO2018209874A1 - 利用氮掺杂二氧化钛强化藻类混凝同时在可见光下降解含藻底泥的方法 - Google Patents

利用氮掺杂二氧化钛强化藻类混凝同时在可见光下降解含藻底泥的方法 Download PDF

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WO2018209874A1
WO2018209874A1 PCT/CN2017/104482 CN2017104482W WO2018209874A1 WO 2018209874 A1 WO2018209874 A1 WO 2018209874A1 CN 2017104482 W CN2017104482 W CN 2017104482W WO 2018209874 A1 WO2018209874 A1 WO 2018209874A1
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algae
weight
parts
tio
powder
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裴海燕
金岩
张莎莎
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Shandong University
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Shandong University
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/007—Contaminated open waterways, rivers, lakes or ponds

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  • the invention relates to the field of drinking water treatment, in particular to a method for strengthening algae coagulation by nitrogen-doped titanium dioxide (N-TiO 2 ) while degrading algae-containing mud under visible light.
  • N-TiO 2 nitrogen-doped titanium dioxide
  • the removal of algae mainly depends on the coagulation process.
  • 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.
  • the technical problem to be solved by the present invention is to provide an algae removal method for improving the efficiency of coagulation and algae removal, and at the same time, degrading the algae-containing mud under visible light and detoxifying the discharged mud water.
  • the present invention provides the following technical solutions:
  • the present invention provides a method for simultaneously treating algae in a body of water and sediment, comprising the steps of:
  • Step (1) adding a algaecide coagulant to the algae-containing water to stir to complete coagulation;
  • the algaecide coagulant 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;
  • 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. After a certain time, the algae and algal toxin are degraded.
  • 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 .
  • the N-TiO 2 powder and the polyaluminum ferric chloride are weighed according to the set weight, and the algae coagulant is obtained after being uniformly mixed.
  • the present invention has the following beneficial effects:
  • 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.
  • 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.
  • 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.
  • FIG 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.
  • 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.
  • the present invention provides a simultaneous treatment of water and sediment.
  • the method of algae includes the following steps:
  • Step (1) adding a algaecide coagulant to the algae-containing water to stir to complete coagulation;
  • the algaecide coagulant comprises the following components by weight: 50-400 parts by weight of N-TiO 2 powder, 7.5 parts by weight of polyaluminum ferric chloride;
  • 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. After a certain period of time (12-48h), the algae and algal toxin are degraded.
  • the above-mentioned algaecide coagulant is composed of the following parts by weight: 200 to 250 parts by weight of N-TiO 2 powder, 7.5 parts by weight of polymerization.
  • Aluminum iron chloride is a 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.
  • 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 .
  • the N-TiO 2 powder is prepared by the following method:
  • 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.
  • the N-TiO 2 powder and the polyaluminum ferric chloride are weighed according to the set weight, and the algae coagulant is obtained after being uniformly mixed.
  • 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.
  • 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.
  • the standing time is 10 to 60 minutes.
  • 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.
  • 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.
  • 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.
  • 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.
  • the dosage of N-TiO 2 powder is 50 ⁇ 400mg / L
  • 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%
  • the algae removal rate is good.
  • 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%.
  • 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.
  • the volume of the treated water sample is 1L, and weigh 50mg of N-TiO 2 powder and 7.5mg of polyaluminum chloride.
  • stir at 250 rpm for 1 min 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.
  • 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.
  • 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.
  • 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.
  • the volume of the treated water sample is 1L, and weigh 100mg of N-TiO 2 powder and 7.5mg of polyaluminum chloride.
  • stir at 250 rpm for 1 min 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.
  • 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.
  • 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 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.
  • the volume of the treated water sample is 1L, and weigh 200mg of N-TiO 2 powder and 7.5mg of polyaluminium chloride.
  • stir at 250 rpm for 1 min 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • Example 1 the algaecide coagulant in Example 3 is preferred.
  • Example 1 and Example 2 the algae in the sediment did not completely degrade within 48 hours, and the treatment effect was not achieved.
  • 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.
  • the present invention uses "photocatalyst and conventional coagulant to strengthen each other.
  • the type of the photocatalyst, the present invention is optimized screened, preferred nitrogen-doped titanium oxide-based photocatalyst as found, compared to TiO 2, TiO 2 after the nitrogen-doped titanium dioxide material other metal or non-doped 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.
  • 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.
  • 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.
  • the algaecide coagulant consists of the following parts by weight: 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.
  • 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.
  • 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%.
  • 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.
  • Fig. 1 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 is the highest, It is 90%.
  • 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.
  • 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.
  • the volume of the treated water sample is 1L, and weigh 200mg of N-TiO 2 powder and 7.5mg of polyaluminium chloride.
  • stir at 250 rpm for 1 min 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.
  • the algae removal rate can reach 80% at 30 min.
  • 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.
  • 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.
  • the volume of the treated water sample is 1L, and weigh 200mg of N-TiO 2 powder and 7.5mg of polyaluminium chloride.
  • stir at 250 rpm for 1 min 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.
  • the algae removal rate can reach 85% at 30 min.
  • 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%.
  • 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.
  • the rare earth doped TiO 2 powder is prepared by the following method:
  • 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.
  • the volume of the treated water sample is 1L, and weigh 200mg of N-TiO 2 powder and 7.5mg of polyaluminium chloride.
  • stir at 250 rpm for 1 min 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.
  • the algae removal rate reached 83% at 30 min.
  • 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%.
  • 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.
  • 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.
  • the volume of the treated water sample is 1L, and weigh 200mg of N-TiO 2 powder and 7.5mg of polyaluminium chloride.
  • stir at 250 rpm for 1 min 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.
  • the algae removal rate can reach 90% at 30 min.
  • 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.
  • 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.
  • 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.

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Abstract

一种利用氮掺杂二氧化钛强化藻类混凝同时在可见光下降解含藻底泥的方法，包括：(1)：向含藻水中加入除藻混凝剂进行搅拌完成混凝，除藻混凝剂由50～400重量份的N-TiO2粉末和7.5重量份聚合氯化铝铁组成；(2)：静置沉淀后，含藻絮体沉降到底部，上清液中藻类被去除；(3)：弃掉上清液，保留底部含藻底泥，放置在可见光下照射并搅拌，一定时间后，藻类以及藻毒素被降解。能减少混凝剂使用量，增强混凝效果，并且能降解底泥中的藻类以及微囊藻毒素，适用处理高藻密度水源及高藻密度底泥。

Description

利用氮掺杂二氧化钛强化藻类混凝同时在可见光下降解含藻底泥的方法 技术领域
本发明涉及饮用水处理领域，特别涉及一种利用氮掺杂二氧化钛(N-TiO2)强化藻类混凝同时在可见光下降解含藻底泥的方法。
背景技术
近年来，我国淡水湖泊水库富营养化现象日益严重，藻类大量繁殖，形成水华，严重影响原水水质。藻类的大量繁殖改变了水体的理化环境，透明度降低，水体散发腥臭味，溶解氧减少，不仅影响了养殖水域生态系统、供水、旅游业及生态景观，还严重干扰了人类的正常生活。
在饮用水工艺中，藻类的去除主要依靠混凝过程。然而，由于藻类具有一定的漂浮性，其产生的絮体不易沉降，从而降低了藻类的去除效率，也增加了后续处理工艺的负担。此外，沉降至底泥中的藻细胞中，存在一些害藻类，如铜绿微囊藻(Microcystisaeruginosa)，能够释放微囊藻毒素，影响人类健康。当排放含有藻毒素的排泥水时，会造成水体的二次污染。因此，如何强化藻类混凝，增强除藻效率并且有效降解含藻底泥，使排泥水无害化排放是当前亟需解决的问题。
发明内容
本发明要解决的技术问题是提供一种提高混凝除藻效率，同时能在可见光下降解含藻底泥并使排泥水无害化排放的除藻方法。
为解决上述技术问题，本发明提供技术方案如下：
本发明提供一种同时处理水体和底泥中藻类的方法，包括以下步骤：
步骤(1)：向含藻水中加入除藻混凝剂进行搅拌完成混凝；
其中，所述除藻混凝剂，是由如下重量份组分组成：50～400重量份的N-TiO2粉末、7.5重量份聚合氯化铝铁；
步骤(2)：静置沉淀后，含藻絮体沉降到底部，上清液中藻类被去除；
步骤(3)：弃掉上清液，保留底部含藻底泥，放置在可见光下照射并搅拌，一定时间后，藻类以及藻毒素被降解。
其中，所述N-TiO2粉末是通过以下方法制备得到的：12～18重量份的钛酸丁酯、18～22重量份的无水乙醇、0.05～0.5重量份的尿素与28～35重量份的稀硝酸溶液在80～100℃下加热3～5小时，之后在400℃～500℃下煅烧3～5小时，得到的白色粉末即为N-TiO2。
其中，所述除藻混凝剂的制备方法，按照设定重量份称取N-TiO2粉末和聚合氯化铝铁， 混合均匀后即得除藻混凝剂。
与现有技术相比，本发明具有如下有益效果：
本发明中，所述除藻混凝剂采用N-TiO2粉末和聚合氯化铝铁进行复配，将单独采用聚合氯化铝铁混凝剂的使用量减少了50％，显著降低了混凝剂使用量并增强了除藻效率。此外，N-TiO2粉末对环境影响小，不会对水体造成二次污染，混凝剂用量的减少也降低了水体中重金属的含量，避免了重金属污染，进一步提高了水质。混凝完成后，N-TiO2粉末随含藻絮体沉降至底泥中，对含藻底泥进行可见光照射同时搅拌，可在12h内降解破裂所有藻类，并在48h内对藻类释放的藻毒素降解率达到85％以上。减少了底泥量，同时提高了排泥水水质，使其能够安全排放或进一步回收利用。
附图说明
构成本发明的一部分的说明书附图用来提供对本发明的进一步理解，本发明的示意性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。
图1为不同剂量的PAFC对藻类的去除效果。
图2为PAFC及PAFC和不同浓度N-TiO2粉末复配的混凝剂在混凝过程中的藻类去除率。
图3为PAFC及PAFC和不同浓度N-TiO2粉末复配的混凝剂在絮体沉降过程中的藻类去除率。
图4为不同浓度N-TiO2粉末在可见光下降解含藻底泥过程中叶绿素的变化情况。
图5为不同浓度N-TiO2粉末在可见光下降解含藻底泥过程中微囊藻毒素(MCs)的变化情况。
具体实施方式
应该指出，以下详细说明都是示例性的，旨在对本发明提供进一步的说明。除非另有指明，本文使用的所有技术和科学术语具有与本发明所属技术领域的普通技术人员通常理解的相同含义。
需要注意的是，这里所使用的术语仅是为了描述具体实施方式，而非意图限制根据本发明的示例性实施方式。如在这里所使用的，除非上下文另外明确指出，否则单数形式也意图包括复数形式，此外，还应当理解的是，当在本说明书中使用术语“包含”和/或“包括”时，其指明存在特征、步骤、操作和/或它们的组合。
本发明中所用的材料、试剂等，如无特殊说明，均可从商业途径得到。
本发明中，藻类去除率、藻细胞降解率以及微囊藻毒素(MCs)降解率的计算公式如下：
藻类去除率(％)＝(实验用水源OD680-上清液OD680)×100％/实验用水源OD680；
藻细胞降解率(％)＝(0h含藻底泥叶绿素含量-所测时间点含藻底泥叶绿素含量)×100％/0h含藻底泥叶绿素含量；
微囊藻毒素降解率(％)＝(含藻底泥中藻细胞完全破裂时微囊藻毒素含量-所测时间点含藻底泥中微囊藻毒素含量)×100％/含藻底泥中藻细胞完全破裂时微囊藻毒素含量。
正如背景技术所介绍的，饮用水工艺中藻类的去除方法存在一定的不足，同时一些藻类释放的有害物质并不能得到有效降解，为了解决如上技术问题，本发明提供一种同时处理水体和底泥中藻类的方法，包括以下步骤：
步骤(1)：向含藻水中加入除藻混凝剂进行搅拌完成混凝；
其中，所述除藻混凝剂，包括如下重量份组分：50～400重量份的N-TiO2粉末、7.5重量份聚合氯化铝铁；
步骤(2)：静置沉淀后，含藻絮体沉降到底部，上清液中藻类被去除；
步骤(3)：弃掉上清液，保留底部含藻底泥，放置在可见光下照射并搅拌，一定时间(12～48h)后，藻类以及藻毒素被降解。
所述步骤(1)中，在本发明的优选的技术方案中，上述除藻混凝剂，是由如下重量份组分组成：200～250重量份的N-TiO2粉末、7.5重量份聚合氯化铝铁。
在本发明的最优选的技术方案中，上述除藻混凝剂，是由如下重量份组分组成：200重量份的N-TiO2粉末、7.5重量份聚合氯化铝铁。
其中，所述N-TiO2粉末是通过以下方法制备得到的：12～18重量份的钛酸丁酯、18～22重量份的无水乙醇、0.05～0.5重量份的尿素与28～35重量份的稀硝酸溶液在80～100℃下加热3～5小时，之后在400℃～500℃下煅烧3～5小时，得到的白色粉末即为N-TiO2。
从提高藻类去除率和降解含藻底泥的效果来讲，在本发明优选的技术方案中，所述N-TiO2粉末是通过以下方法制备得到的：
15重量份的钛酸丁酯加入到20重量份的无水乙醇中，搅拌后得到溶液A；
0.05～0.5重量份的尿素加入到30重量份的稀硝酸溶液中，混合形成溶液B；
在搅拌条件下，溶液A缓慢加入到溶液B中，用氢氧化钠溶液调节pH至7，在80℃下加热3小时；
之后将体系离心弃上清，沉淀水洗3遍，在400℃～500℃下煅烧3小时，得到的白色粉末即为N-TiO2。
所述N-TiO2粉末的粒径为50～150目；更优选的，所述N-TiO2粉末的粒径为100目。
在本发明优选的技术方案中，所述除藻混凝剂的制备方法，按照设定重量份称取N-TiO2粉末和聚合氯化铝铁，混合均匀后即得除藻混凝剂。
其中，所述步骤(1)中，所述含藻水的密度为105～107cells/mL，搅拌的条件为150～250rpm搅拌1～2min，30～60rpm搅拌10～20min。
混凝剂PAFC剂量为半优剂量7.5mg/L(不加N-TiO2的最优剂量为15mg/L)，N-TiO2剂量为50～400mg/L。将PAFC和N-TiO2投入含藻水中快速搅拌使其迅速分散形成微细矾花，此时水体变得更加浑浊，使水流能产生激烈的湍流，在絮凝阶段是矾花成长变粗的过程，要求适当的湍流程度和足够的停留时间(10～20min)，至后期可观察到大量矾花聚集依靠重力缓缓下沉。混凝过程中测定上清液(液面下2cm处)余浊的OD680值，考察混凝过程中絮体的沉降情况。
所述步骤(2)中，静置时间为10～60min。沉降阶段中大量的粗大矾花而沉积，上层水为澄清水，剩下的粒径小、密度小的矾花一边缓缓下降，一边继续相互碰撞结大，至后期余浊基本不变。测定沉降过程中上清液余浊的OD680值，考察絮体完全沉降所需时间。
通常水体中藻类细胞具有数量多、比重小，表面带较高的负电荷等特点而难以去除。此外，藻类细胞形成的絮体具有一定的漂浮性，使其难以沉降，降低了除藻效率。聚合氯化铝铁是一种高效的无机高分子混凝剂，当在混凝过程中加入适量的N-TiO2粉末时，N-TiO2可作为混凝剂破稳产生的微型絮团的核心，配合聚合氯化铝铁利用沉淀物网捕机理、电中和及桥联作用使混凝后的藻细胞形成矾花迅速且沉降速度快，去除藻类效果好。
所述步骤(3)中，弃掉的上清液体积占总体积的93％～97％，光照强度为3000～15000Lux，搅拌速度为200～800rpm。
TiO2半导体由于具有无毒、价廉、性能稳定和耐腐蚀性等优点成为应用最广泛的光催化剂。然而，从其光催化效率来看.二氧化钛光催化剂还存在一些局限性：由于其禁带宽度为3.2eV，光吸收波段窄(主要在紫外区)，太阳光利用效率低；半导体载流子的复合率高，量子效率低等。而非金属元素N的引入.可以扩大TiO2光响应范围，从而提高其在可见光区的光催化活性。因此，N-TiO2能在可见光下高效降解藻类、藻毒素以及胞内胞外有机物。
当初始藻浓度为105～107cells/mL时，N-TiO2粉末的投放量为50～400mg/L，聚合氯化铝铁的混合投放量为半优剂量7.5mg/L(不加N-TiO2的最优剂量为15mg/L)，藻类去除率可达96％以上，去藻率好。在降解含藻底泥过程中，12h内，藻类全部被降解破裂，48h内，藻类释放的藻毒素的降解率达到85％以上。
为了使得本领域技术人员能够更加清楚地了解本发明的技术方案，以下将结合具体的实施例与对比例详细说明本发明的技术方案。
实施例1
除藻混凝剂由以下重量份的组分组成：50重量份的N-TiO2粉末(粒径100目)以及7.5重量份聚合氯化铝铁。
实验所使用的铜绿微囊藻(Microcystisaeruginosa)采用BG11培养基培养，温度25℃，光照12小时，黑暗12小时，光照强度2000lux，培养至对数生长阶段，用于配制实验用含藻水源。
用去离子水将藻液浓度稀释至1×106cells/mL，配制成实验用水源，处理水样体积为1L，称取N-TiO2粉末50mg、聚合氯化铝铁7.5mg混合加入到每升实验水源中，250rpm快搅拌1min，30rpm慢搅拌30min完成混凝过程。分别在混凝过程以及混凝完成后2h内，取液面下两厘米处的上清液，检测其在680nm波长处的吸光度(OD680)，藻类去除率在混凝完成后1h达到最大值，为96％。见图2和3。
含藻絮体沉降后，弃掉上清液，余下的部分即为含藻底泥，约占原体积的7％。将含藻底泥放置在8000lux的可见光下照射同时以500rpm转速搅拌，48h后，41.6％的藻细胞被降解，部分微囊藻毒素还存在于藻细胞内。见图4和5。
实施例2
除藻混凝剂由以下重量份的组分组成：100重量份的N-TiO2粉末(粒径100目)以及7.5重量份聚合氯化铝铁。
实验所使用的铜绿微囊藻(Microcystisaeruginosa)采用BG11培养基培养，温度25℃，光照12小时，黑暗12小时，光照强度2000lux，培养至对数生长阶段，用于配制实验用含藻水源。
用去离子水将藻液浓度稀释至1×106cells/mL，配制成实验用水源，处理水样体积为1L，称取N-TiO2粉末100mg、聚合氯化铝铁7.5mg混合加入到每升实验水源中，250rpm快搅拌1min，30rpm慢搅拌30min完成混凝过程。分别在混凝过程以及混凝完成后2h内，取液面下两厘米处的上清液，检测其在680nm波长处的吸光度(OD680)，藻类去除率在混凝完成后1h达到最大值，为97％。见图2和3。
含藻絮体沉降后，弃掉上清液，余下的部分即为含藻底泥，约占原体积的7％。将含藻底泥放置在8000lux的可见光下照射同时以500rpm转速搅拌，48h后，59.9％的藻细胞被降解，部分微囊藻毒素还存在于藻细胞内。见图4和5。
实施例3
除藻混凝剂由以下重量份的组分组成：200重量份的N-TiO2粉末(粒径100目)以及7.5重量份聚合氯化铝铁。
实验所使用的铜绿微囊藻(Microcystisaeruginosa)采用BG11培养基培养，温度25℃，光照12小时，黑暗12小时，光照强度2000lux，培养至对数生长阶段，用于配制实验用含藻水源。
用去离子水将藻液浓度稀释至1×106cells/mL，配制成实验用水源，处理水样体积为1L，称取N-TiO2粉末200mg、聚合氯化铝铁7.5mg混合加入到每升实验水源中，250rpm快搅拌1min，30rpm慢搅拌30min完成混凝过程。分别在混凝过程以及混凝完成后2h内，取液面下两厘米处的上清液，检测其在680nm波长处的吸光度(OD680)，藻类去除率在混凝完成后10min达到最大值，为98％。见图2和3。
含藻絮体沉降后，弃掉上清液，余下的部分即为含藻底泥，约占原体积的7％。将含藻底泥放置在8000lux的可见光下照射同时以500rpm转速搅拌，12h后，全部藻细胞被降解，48h后微囊藻毒素的降解率为84.2％。见图4和5。
实施例4
除藻混凝剂由以下重量份的组分组成：400重量份的N-TiO2粉末(粒径100目)以及7.5重量份聚合氯化铝铁。
实验所使用的铜绿微囊藻(Microcystisaeruginosa)采用BG11培养基培养，温度25℃，光照12小时，黑暗12小时，光照强度2000lux，培养至对数生长阶段，用于配制实验用含藻水源。
用去离子水将藻液浓度稀释至1×106cells/mL，配制成实验用水源，处理水样体积为1L，称取N-TiO2粉末400mg、聚合氯化铝铁7.5mg混合加入到每升实验水源中，250rpm快搅拌1min，30rpm慢搅拌30min完成混凝过程。分别在混凝过程以及混凝完成后2h内，取液面下两厘米处的上清液，检测其在680nm波长处的吸光度(OD680)，藻类去除率在混凝完成后10min达到最大值，为98％。见图2和3。
含藻絮体沉降后，弃掉上清液，余下的部分即为含藻底泥，约占原体积的7％。将含藻底泥放置在8000lux的可见光下照射同时以500rpm转速搅拌，12h后，全部藻细胞被降解，48h后微囊藻毒素的降解率为87.6％。见图4和5。
实施例1至实施例4中，优选实施例3中的除藻混凝剂。实施例1与实施例2中，底泥中藻类在48h内没有完全降解，未达到处理效果。实施例4中，N-TiO2粉末加入量过大，混凝完成后部分残留于上清液中，影响水质且增加了处理成本。
在面对“如何强化藻类混凝、增强除藻效率、降低常规混凝剂的用量，并且同时有效降解含藻底泥”的技术问题，本发明采用“光催化剂与常规混凝剂相互配合强化藻类混凝并在可见光下降解含藻底泥”的基本思路，并在该思路下对原料以及原料配比含量进行筛选和优 化。对于光催化剂的种类，本发明人经过筛选优化，首选氮掺杂二氧化钛类光催化剂，因为研究发现，相比于其他金属或非金属掺杂的TiO2，TiO2经过氮掺杂之后，二氧化钛材料的电荷平衡受到一定破坏，正是根据此特点，其可作为混凝剂破稳产生的微型絮团的核心，配合聚合氯化铝利于混凝剂的分散和絮团的形成，增强絮凝效果，可以解决短时间矾花上浮的现象；另外，氮掺杂的TiO2在可见光下降解藻类、藻毒素及胞内胞外有机物。而对于混凝剂的筛选，针对藻类的特点，本申请优先选择聚合氯化铝铁，它集铝盐和铁盐各自优点，对铝离子和铁离子的形态都有明显改善，聚合程度大为提高；与氮掺杂的TiO2相互配合，发挥处理含藻水体的最大功效；而对于用量的选择，优选7.5重量份聚合氯化铝铁，当N-TiO2用量一定(处理效果最好、用量最低时)，当大于7.5重量份聚合氯化铝铁时，藻类去除率反而会有所下降；当小于7.5重量份聚合氯化铝铁时，无论N-TiO2的用量为何值，其处理效果无法达到最优，综合考虑，选择7.5重量份聚合氯化铝铁与50～400重量份的N-TiO2粉末。
在研究各种原料以及原料配比量处理含藻水体的效果时，结果发现，不同原料组合对于处理含藻水体的效果具有显著的差异，仅以对比例1～5为例，但所做研究不仅仅限于以下对比例。
对比例1
除藻混凝剂由以下重量份的组分组成：7.5重量份聚合氯化铝铁。
实验所使用的铜绿微囊藻(Microcystisaeruginosa)采用BG11培养基培养，温度25℃，光照12小时，黑暗12小时，光照强度2000lux，培养至对数生长阶段，用于配制实验用含藻水源。
用去离子水将藻液浓度稀释至1×106cells/mL，配制成实验用水源，处理水样体积为1L，称取聚合氯化铝铁7.5mg混合加入到每升实验水源中，250rpm快搅拌1min，30rpm慢搅拌30min完成混凝过程。分别在混凝过程以及混凝完成后2h内，取液面下两厘米处的上清液，检测其在680nm波长处的吸光度(OD680)，藻类去除率见图2、图3，由图2可得，絮凝速度慢、混凝过程中藻类去除率低，仅为5～6％，由图3可得，絮体沉降过程中在30min时，藻类去除率仅为60％左右，在120min藻类去除率才达到最大值，仅为80％。
含藻絮体沉降后，弃掉上清液，余下的部分即为含藻底泥，约占原体积的7％。将含藻底泥放置在8000lux的可见光下照射同时以500rpm转速搅拌，藻细胞降解率见图4，微囊藻毒素变化见图5，叶绿素和微囊藻毒素的含量的变化不大。
单独使用PAFC时，对藻类的去除效果如图1所示，从图1中可得，当PAFC的剂量为7.5mg/L时，藻类去除率仅为60％左右，当PAFC的剂量为15mg/L，藻类去除率达到最大， 为90％。
对比例2
除藻混凝剂由以下重量份的组分组成：200重量份的N-TiO2粉末(粒径100目)以及7.5重量份聚合硅酸铝铁。
实验所使用的铜绿微囊藻(Microcystisaeruginosa)采用BG11培养基培养，温度25℃，光照12小时，黑暗12小时，光照强度2000lux，培养至对数生长阶段，用于配制实验用含藻水源。
用去离子水将藻液浓度稀释至1×106cells/mL，配制成实验用水源，处理水样体积为1L，称取N-TiO2粉末200mg、聚合氯化铝铁7.5mg混合加入到每升实验水源中，250rpm快搅拌1min，30rpm慢搅拌30min完成混凝过程。分别在混凝过程以及混凝完成后2h内，取液面下两厘米处的上清液，检测其在680nm波长处的吸光度(OD680)。絮体沉降过程中，在30min时藻类去除率才能达到80％。
对比例3
除藻混凝剂由以下重量份的组分组成：200重量份的TiO2粉末(粒径100目)以及7.5重量份聚合氯化铝铁。
实验所使用的铜绿微囊藻(Microcystisaeruginosa)采用BG11培养基培养，温度25℃，光照12小时，黑暗12小时，光照强度2000lux，培养至对数生长阶段，用于配制实验用含藻水源。
用去离子水将藻液浓度稀释至1×106cells/mL，配制成实验用水源，处理水样体积为1L，称取N-TiO2粉末200mg、聚合氯化铝铁7.5mg混合加入到每升实验水源中，250rpm快搅拌1min，30rpm慢搅拌30min完成混凝过程。分别在混凝过程以及混凝完成后2h内，取液面下两厘米处的上清液，检测其在680nm波长处的吸光度(OD680)。絮体沉降过程中，在30min时藻类去除率才能达到85％。
含藻絮体沉降后，弃掉上清液，余下的部分即为含藻底泥，约占原体积的7％。将含藻底泥放置在8000lux的可见光下照射同时以500rpm转速搅拌。48h后仅有49％的藻细胞被降解，48h后微囊藻毒素的降解率仅为48.4％。
对比例4
除藻混凝剂由以下重量份的组分组成：200重量份的稀土掺杂TiO2粉末(粒径100目)以及7.5重量份聚合硅酸铝铁。
其中，稀土掺杂TiO2粉末是通过以下方法制备得到的：
取无水乙醇20ml，然后加入钛酸丁酯，搅拌2h后，加入稀土镧硝酸盐溶液水解后，继续 强力搅拌至生成凝胶，取出干燥，在400℃马弗炉中焙烧5h，得到稀土掺杂TiO2粉末。
实验所使用的铜绿微囊藻(Microcystisaeruginosa)采用BG11培养基培养，温度25℃，光照12小时，黑暗12小时，光照强度2000lux，培养至对数生长阶段，用于配制实验用含藻水源。
用去离子水将藻液浓度稀释至1×106cells/mL，配制成实验用水源，处理水样体积为1L，称取N-TiO2粉末200mg、聚合氯化铝铁7.5mg混合加入到每升实验水源中，250rpm快搅拌1min，30rpm慢搅拌30min完成混凝过程。分别在混凝过程以及混凝完成后2h内，取液面下两厘米处的上清液，检测其在680nm波长处的吸光度(OD680)。絮体沉降过程中，在30min时藻类去除率才能达到83％。
含藻絮体沉降后，弃掉上清液，余下的部分即为含藻底泥，约占原体积的7％。将含藻底泥放置在8000lux的可见光下照射同时以500rpm转速搅拌。48h后仅有43％的藻细胞被降解，48h后微囊藻毒素的降解率仅为45.6％。
对比例5
除藻混凝剂由以下重量份的组分组成：200重量份的N-TiO2粉末(粒径100目)以及10重量份聚合氯化铝铁。
实验所使用的铜绿微囊藻(Microcystisaeruginosa)采用BG11培养基培养，温度25℃，光照12小时，黑暗12小时，光照强度2000lux，培养至对数生长阶段，用于配制实验用含藻水源。
用去离子水将藻液浓度稀释至1×106cells/mL，配制成实验用水源，处理水样体积为1L，称取N-TiO2粉末200mg、聚合氯化铝铁7.5mg混合加入到每升实验水源中，250rpm快搅拌1min，30rpm慢搅拌30min完成混凝过程。分别在混凝过程以及混凝完成后2h内，取液面下两厘米处的上清液，检测其在680nm波长处的吸光度(OD680)。絮体沉降过程中，在30min时藻类去除率才能达到90％。
综上，本发明提供的除藻混凝剂采用PAFC与N-TiO2粉末复配，与单独混凝剂或其他混凝剂相比，混凝剂的用量减少了50％，显著降低了水处理成本，并且除藻效率大于96％，效果显著高于对比例1～5，其中N-TiO2粉末对环境影响小，不会对水体造成二次污染。混凝完成后，N-TiO2粉末随含藻絮体沉降至底泥中，对含藻底泥进行可见光照射同时搅拌，在适当的N-TiO2剂量下，可在12h内降解破裂所有藻类，并在48h内对藻类释放的藻毒素降解率达到85％以上，效果显著高于对比例1～5。减少了底泥量，同时提高了排泥水水质，使其能够安全排放或进一步回收利用。另外，本发明的除藻混凝剂中各组分的用量也是非常关键的，发明人在试验过程中，对原料用量进行了调整，结果发现，调整用量后的除藻 混凝剂的藻类去除率和降解含藻底泥的效果显著下降。
上述实施例为本发明较佳的实施方式，但本发明的实施方式并不受上述实施例的限制，其他的任何未背离本发明的精神实质与原理下所作的改变、修饰、替代、组合、简化，均应为等效的置换方式，都包含在本发明的保护范围之内。

Claims (10)

  1. 一种同时处理水体和底泥中藻类的方法，其特征是，包括以下步骤：
    步骤(1)：向含藻水中加入除藻混凝剂进行搅拌完成混凝；
    其中，所述除藻混凝剂，是由如下重量份组分组成：50～400重量份的N-TiO2粉末、7.5重量份聚合氯化铝铁；
    步骤(2)：静置沉淀后，含藻絮体沉降到底部，上清液中藻类被去除；
    步骤(3)：弃掉上清液，保留底部含藻底泥，放置在可见光下照射并搅拌，一定时间后，藻类以及藻毒素被降解。
  2. 如权利要求1所述的方法，其特征是，步骤(1)中，所述除藻混凝剂是由如下重量份组分组成：200～250重量份的N-TiO2粉末、7.5重量份聚合氯化铝铁。
  3. 如权利要求2所述的方法，其特征是，所述除藻混凝剂是由如下重量份组分组成：200重量份的N-TiO2粉末、7.5重量份聚合氯化铝铁。
  4. 如权利要求1所述的方法，其特征是，步骤(1)中，所述N-TiO2粉末是通过以下方法制备得到的：12～18重量份的钛酸丁酯、18～22重量份的无水乙醇、0.05～0.5重量份的尿素与28～35重量份的稀硝酸溶液在80～100℃下加热3～5小时，之后在400℃～500℃下煅烧3～5小时，得到的白色粉末即为N-TiO2。
  5. 如权利要求4所述的方法，其特征是，所述N-TiO2粉末的粒径为50～150目；
    优选的，所述N-TiO2粉末的粒径为100目。
  6. 如权利要求1所述的方法，其特征是，步骤(1)中，所述除藻混凝剂的制备方法包括以下步骤：按照设定重量份称取N-TiO2粉末和聚合氯化铝铁，混合均匀后即得除藻混凝剂。
  7. 如权利要求1所述的方法，其特征是，步骤(1)中，所述含藻水的密度为105～107cells/mL，搅拌的条件为150～250rpm搅拌1～2min，30～60rpm搅拌10～20min。
  8. 如权利要求7所述的方法，其特征是，步骤(1)中，含藻水中含有的聚合氯化铝铁的浓度为7.5mg/L；含藻水中含有的N-TiO2的浓度为50～400mg/L。
  9. 如权利要求1所述的方法，其特征是，步骤(2)中，静置时间为10～60min。
  10. 如权利要求1所述的方法，其特征是，步骤(3)中，弃掉的上清液体积占总体积的93％～97％，光照强度为3000～15000Lux，搅拌速度为200～800rpm。
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