CN108147496B - Method for degrading water pollutants by using nano photocatalyst flocs - Google Patents
Method for degrading water pollutants by using nano photocatalyst flocs Download PDFInfo
- Publication number
- CN108147496B CN108147496B CN201711396046.XA CN201711396046A CN108147496B CN 108147496 B CN108147496 B CN 108147496B CN 201711396046 A CN201711396046 A CN 201711396046A CN 108147496 B CN108147496 B CN 108147496B
- Authority
- CN
- China
- Prior art keywords
- nano
- flocs
- photocatalyst
- coagulation
- nano photocatalyst
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000011941 photocatalyst Substances 0.000 title claims abstract description 46
- 238000000034 method Methods 0.000 title claims abstract description 36
- 230000000593 degrading effect Effects 0.000 title claims abstract description 13
- 239000003403 water pollutant Substances 0.000 title claims abstract description 13
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 67
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 31
- 238000005345 coagulation Methods 0.000 claims abstract description 29
- 230000015271 coagulation Effects 0.000 claims abstract description 28
- 238000003756 stirring Methods 0.000 claims abstract description 24
- 239000004408 titanium dioxide Substances 0.000 claims abstract description 18
- 239000002351 wastewater Substances 0.000 claims abstract description 12
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims abstract description 9
- 239000000701 coagulant Substances 0.000 claims abstract description 9
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims abstract description 9
- 230000008569 process Effects 0.000 claims abstract description 7
- 238000013033 photocatalytic degradation reaction Methods 0.000 claims abstract description 6
- 239000003344 environmental pollutant Substances 0.000 claims abstract description 5
- 231100000719 pollutant Toxicity 0.000 claims abstract description 5
- 239000006185 dispersion Substances 0.000 claims abstract description 3
- 230000001678 irradiating effect Effects 0.000 claims abstract description 3
- 239000000203 mixture Substances 0.000 claims abstract description 3
- 239000000843 powder Substances 0.000 claims description 26
- 230000015556 catabolic process Effects 0.000 claims description 16
- 238000006731 degradation reaction Methods 0.000 claims description 16
- 239000006228 supernatant Substances 0.000 claims description 14
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 9
- 229910017604 nitric acid Inorganic materials 0.000 claims description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 8
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 8
- FPCJKVGGYOAWIZ-UHFFFAOYSA-N butan-1-ol;titanium Chemical compound [Ti].CCCCO.CCCCO.CCCCO.CCCCO FPCJKVGGYOAWIZ-UHFFFAOYSA-N 0.000 claims description 8
- 239000004202 carbamide Substances 0.000 claims description 8
- 238000001354 calcination Methods 0.000 claims description 4
- 238000005119 centrifugation Methods 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 4
- 238000002360 preparation method Methods 0.000 claims description 4
- 238000005286 illumination Methods 0.000 claims description 3
- 239000010842 industrial wastewater Substances 0.000 claims description 2
- 230000007935 neutral effect Effects 0.000 claims description 2
- 239000010865 sewage Substances 0.000 claims description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 abstract description 14
- 239000000463 material Substances 0.000 abstract description 13
- 230000000694 effects Effects 0.000 abstract description 7
- 238000000926 separation method Methods 0.000 abstract description 4
- 238000004065 wastewater treatment Methods 0.000 abstract description 3
- STZCRXQWRGQSJD-UHFFFAOYSA-M sodium;4-[[4-(dimethylamino)phenyl]diazenyl]benzenesulfonate Chemical compound [Na+].C1=CC(N(C)C)=CC=C1N=NC1=CC=C(S([O-])(=O)=O)C=C1 STZCRXQWRGQSJD-UHFFFAOYSA-M 0.000 description 16
- 230000001699 photocatalysis Effects 0.000 description 13
- STZCRXQWRGQSJD-GEEYTBSJSA-M methyl orange Chemical compound [Na+].C1=CC(N(C)C)=CC=C1\N=N\C1=CC=C(S([O-])(=O)=O)C=C1 STZCRXQWRGQSJD-GEEYTBSJSA-M 0.000 description 6
- 229940012189 methyl orange Drugs 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 239000002086 nanomaterial Substances 0.000 description 5
- 229940037003 alum Drugs 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000002835 absorbance Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000002105 nanoparticle Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005189 flocculation Methods 0.000 description 1
- 230000016615 flocculation Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 238000000703 high-speed centrifugation Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 230000004298 light response Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 239000011943 nanocatalyst Substances 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical compound [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- 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
- C02F1/30—Treatment of water, waste water, or sewage by irradiation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/24—Nitrogen compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/28—Regeneration or reactivation
-
- B01J35/39—
-
- B01J35/40—
-
- B01J35/50—
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2305/00—Use of specific compounds during water treatment
- C02F2305/10—Photocatalysts
Abstract
The invention discloses a method for degrading water pollutants by using nano photocatalyst flocs, which comprises the following steps: 1) adding the nano photocatalyst into water for uniform dispersion, then adding a coagulant into the water, stirring the mixture to finish coagulation, and forming nano photocatalyst flocs in the coagulation process; the nano photocatalyst is nano nitrogen-doped titanium dioxide (N-TiO)2) The coagulant is polyaluminum ferric chloride (PAFC); 2) after the coagulation is finished, separating out the generated floc to obtain nano photocatalyst floc; 3) adding the nano photocatalyst flocs obtained in the step 2) into the wastewater to be treated, and irradiating the wastewater under visible light to complete the photocatalytic degradation of pollutants in the wastewater. The nano-photocatalyst material is made into flocs, and the nano-photocatalyst can be separated from the water body by adopting a simple centrifugal separation step. The prepared flocs can be uniformly dispersed in a water body to be treated, and the efficiency and the treatment effect of wastewater treatment are improved by matching with visible light.
Description
Technical Field
The invention relates to the field of water treatment, in particular to a method for degrading water pollutants by using nano photocatalyst flocs.
Background
In recent years, research on the degradation of water pollutants by using nano photocatalytic materials has been widely reported. The method has good effect, the byproduct generation amount is small, and the secondary pollution of the water body is not easy to cause, so the method is considered as the future development direction of pollutant degradation. However, because the nano-material has a small size, the nano-material can be quickly and uniformly dispersed after being added into a water body, and the existing separation method can not realize the separation of the nano-material from the water body at low cost, and can not recycle the nano-material, so that the treatment cost is greatly increased, and the large-scale application of the nano-photocatalyst in the aspect of degrading water body pollutants is limited. And the water body dispersed with the nano material is easily absorbed by human body through biological chain after being discharged into the environment. The nanometer material has small particles, so the nanometer material can easily enter the position where the large particles are difficult to reach in a human body, and potential safety hazards are caused to the health of the human body.
In the prior art, in order to avoid that the nano photocatalytic material is difficult to separate from the water body, the nano photocatalytic material is used after being loaded, for example, nano titanium dioxide is loaded on a stainless steel net, and then the water body after coagulation and precipitation flows through the stainless steel net for photocatalytic degradation. But the method has low efficiency and poor treatment effect for treating the wastewater.
Therefore, how to improve the easy recovery of the nano photocatalytic material with low cost, reduce the residue of the nano photocatalytic material in the water body and effectively improve the wastewater treatment efficiency is an urgent problem to be solved.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention aims to provide a method for degrading water pollutants by using nano photocatalyst flocs.
In order to solve the technical problems, the technical scheme of the invention is as follows:
a method for degrading water pollutants by using nano photocatalyst flocs comprises the following steps:
1) adding the nano photocatalyst into water for uniform dispersion, then adding a coagulant into the water, stirring the mixture to finish coagulation, and forming nano photocatalyst flocs in the coagulation process; the nano photocatalyst is nano nitrogen-doped titanium dioxide (N-TiO)2) The coagulant is polyaluminum ferric chloride (PAFC);
2) after the coagulation is finished, separating out the generated floc to obtain nano photocatalyst floc;
3) adding the nano photocatalyst flocs obtained in the step 2) into the wastewater to be treated, and irradiating the wastewater under visible light to complete the photocatalytic degradation of pollutants in the wastewater.
The nano-photocatalyst material is made into flocs, and the nano-photocatalyst can be separated from the water body by adopting a simple centrifugal separation step. And the prepared flocs can be uniformly dispersed in a water body to be treated and can be matched with visible light, so that the wastewater treatment efficiency and treatment effect are improved.
Preferably, in the step 1), the mass ratio of the nano nitrogen-doped titanium dioxide to the polyaluminium ferric chloride is 20-100:1-5, and preferably 20-30: 1.
When the proportion is adopted, the nano nitrogen-doped titanium dioxide can be more thoroughly coagulated, and the waste of the nano nitrogen-doped titanium dioxide is avoided.
Preferably, in the step 2), after coagulation is completed, the reaction system is kept stand, when the flocs are completely settled to the bottom, the supernatant is discarded, and the rest part is centrifuged to obtain the nano photocatalyst flocs.
Further preferably, in the step 2), the standing time is 5-60 min.
Further preferably, in the step 2), the rotation speed during centrifugation is 2000-.
Preferably, in the step 3), the intensity of the visible light illumination is 3000-.
Preferably, in the step 1), the stirring speed of the nano photocatalyst uniformly dispersed in water is 150-250rpm, and the stirring time is 1-2 min; the stirring speed during coagulation is 30-60rpm, and the stirring time is 10-20 min.
Preferably, the preparation method of the nano nitrogen-doped titanium dioxide comprises the following steps: 12-18 parts of butyl titanate, 18-22 parts of absolute ethyl alcohol, 0.05-0.5 part of urea and 28-35 parts of dilute nitric acid solution by weight are mixed, heated for 3-5 hours at 80-100 ℃, and then calcined for 3-5 hours at 400-500 ℃ to obtain white powder, namely the nano nitrogen-doped titanium dioxide.
Further preferably, the preparation method of the nano nitrogen-doped titanium dioxide comprises the following steps:
1) mixing butyl titanate and absolute ethyl alcohol to obtain a solution A, and dissolving urea in a dilute nitric acid solution to obtain a solution B;
2) and slowly adding the solution A into the solution B under the stirring condition, adjusting the pH value of the solution to be neutral, heating for reaction, and then calcining to obtain the nano nitrogen-doped titanium dioxide.
Still more preferably, the concentration of the dilute nitric acid is 1 mol/L.
More preferably, the weight ratio of the butyl titanate, the absolute ethyl alcohol, the urea and the dilute nitric acid is 15:20:0.05-0.5: 30.
The method for degrading the water pollutants by using the nano photocatalyst flocs comprises the step of recycling the nano photocatalyst flocs, and particularly, the nano photocatalyst flocs can be separated from the wastewater after the degradation is finished and can be reused.
The method for degrading water pollutants by using the nano photocatalyst flocs is applied to degrading organic wastewater such as domestic sewage, industrial wastewater and the like.
The invention has the beneficial effects that:
the nano-level photocatalytic material is made into flocs which can be completely recovered under the common centrifugal condition. The adopted coagulation mode has low cost, small influence on the environment and strong practical applicability. If the nano-sized photocatalyst is directly centrifuged, the material cannot be recovered even under high speed centrifugation conditions (rotation speed greater than 10000 rpm). Besides, the photocatalytic material floc still maintains a good photocatalytic effect, the methyl orange solution can be completely decolorized, the photocatalytic effect is only slightly reduced after recovery, the recycling effect is good, and the cost of the process is greatly reduced.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
FIG. 1 shows different doses of PAFC versus different doses of N-TiO2The coagulation effect of (2) is compared with that of (3).
FIG. 2 shows the dosage of nano N-TiO2And (3) comparing the degradation efficiency of the flocs on the methyl orange solution.
FIG. 3 shows a view of nano-sized N-TiO2Comparative figure for floc recycling.
Detailed Description
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, 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.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and/or combinations thereof, unless the context clearly indicates otherwise.
The materials, reagents and the like used in the present invention are commercially available unless otherwise specified.
In the invention, nano N-TiO2The calculation formula of the coagulation efficiency and the methyl orange degradation efficiency is as follows:
nano N-TiO2Coagulation efficiency (%) (concentration of suspended solid particles in the solution before coagulation-concentration of suspended solid particles in the supernatant after coagulation) × 100%/concentration of suspended solid particles in the solution before coagulation;
methyl orange degradation efficiency (%) (absorbance of 0h methyl orange solution at maximum absorption wavelength-absorbance of methyl orange solution at maximum absorption wavelength at time point measured) × 100%/absorbance of 0h methyl orange solution at maximum absorption wavelength;
as described in the background art, the recoverability of the nano-catalyst has certain defects, and in order to solve the technical problems, the invention provides a method for degrading water pollutants by using nano-photocatalyst flocs, which comprises the following steps:
step (1): adding the nano photocatalyst powder into a water body, adding a coagulant after the nano photocatalyst powder is uniformly dispersed, stirring to finish coagulation, and forming nano photocatalyst flocs in the coagulation process;
wherein the photocatalyst is nano nitrogen-doped titanium dioxide (N-TiO)2) Powder, wherein the coagulant is polyaluminum ferric chloride (PAFC);
wherein the N-TiO is2The powder is prepared by the following method: 12-18 parts by weight of butyl titanate, 18-22 parts by weight of absolute ethyl alcohol, 0.05-0.5 part by weight of urea and 28-35 parts by weight of dilute nitric acid solution are heated at 80-100 ℃ for 3-5 hours, and then at 400-500 DEG CCalcining for 3-5 hours to obtain white powder which is N-TiO2。
Step (2): after coagulation is finished, the system is kept stand, supernatant is discarded when flocs are completely settled to the bottom, and the residual floc solution is centrifuged and separated to obtain nano photocatalyst flocs;
and (3): adding the photocatalytic floc into a methyl orange solution, placing the system under visible light for irradiation, and decoloring the methyl orange after a certain time;
and (4): and (3) centrifuging the decolorized methyl orange solution, completely separating the nano photocatalytic floc, and continuously adding the recovered floc into the untreated methyl orange solution for photocatalytic degradation.
In the step (1), in the preferred technical scheme of the invention, the nano N-TiO is adopted2200 to 1000 parts of powder and 10 to 50 parts of polyaluminum ferric chloride.
In the most preferred technical scheme of the invention, the nano N-TiO2500 parts of powder and 20 parts of polyaluminum ferric chloride.
Wherein the N-TiO is2The powder is prepared by the following method: heating 12-18 parts by weight of butyl titanate, 18-22 parts by weight of absolute ethyl alcohol, 0.05-0.5 part by weight of urea and 28-35 parts by weight of dilute nitric acid solution at 80-100 ℃ for 3-5 hours, and calcining at 400-500 ℃ for 3-5 hours to obtain white powder, namely N-TiO2。
In the preferred technical scheme of the invention, from the viewpoint of improving the effect of photocatalytic degradation, the N-TiO2The powder is prepared by the following method:
adding 15 parts by weight of butyl titanate into 20 parts by weight of absolute ethyl alcohol, and stirring to obtain a solution A;
adding 0.05-0.5 part by weight of urea into 30 parts by weight of dilute nitric acid solution, and mixing to form a solution B;
slowly adding the solution A into the solution B under the stirring condition, adjusting the pH to 7 by using a sodium hydroxide solution, and heating for 3 hours at 80 ℃;
then the system is separatedDiscarding the supernatant, washing the precipitate for 3 times, calcining at 400-500 ℃ for 3 hours to obtain white powder, namely N-TiO2。
Wherein in the step (1), the stirring condition is 150-250rpm for 1-2min, and 30-60rpm for 10-20 min.
Mixing PAFC with N-TiO2The method is characterized in that the method is put into water and quickly stirred to quickly disperse the fine alum flocs to form fine alum flocs, the water body becomes more turbid at the moment, water flow can generate violent turbulence, the flocculation stage is a process that the alum flocs grow and become coarse, proper turbulence degree and enough retention time (10-20 min) are required, and a large amount of alum flocs can be observed to gather and slowly sink depending on gravity at the later stage.
In the step (2), the standing time is 5-60 min. A large amount of coarse alumen ustum is deposited in the settling stage, the upper layer water is clear water, the rest alumen ustum with small particle size and small density gradually decreases while continuously colliding with each other to be larger until the later stage of N-TiO2The flocs are completely settled.
In the step (2), the centrifugal speed is 2000-5000rpm, and the centrifugal time is 5-10 min.
In the step (3), the illumination intensity is 3000-15000Lux, and the stirring speed is 200-1000 rpm.
TiO2The semiconductor is the most widely used photocatalyst due to its advantages of non-toxicity, low cost, stable performance and corrosion resistance. However, titanium dioxide photocatalysts also have some limitations in terms of their photocatalytic efficiency: the forbidden band width is 3.2eV, the light absorption waveband is narrow (mainly in an ultraviolet region), and the sunlight utilization efficiency is low; high recombination rate of semiconductor carriers, low quantum efficiency, and the like. But not the introduction of the metal element N, can enlarge TiO2The light response range, thereby improving the photocatalytic activity in the visible light region. Thus, N-TiO2Can efficiently reduce the water pollutants under visible light.
In the step (4), the nano N-TiO can be completely recovered by each centrifugation2A floc.
1-5 g of nano N-TiO when the initial methyl orange concentration is 0.01-0.05 mM2Adding the flocculate obtained after powder coagulation into 100mLMethyl orange solution. Within 20 hours, the degradation rate of the methyl orange can reach 100 percent
In order to make the technical solutions of the present invention more clearly understood by those skilled in the art, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.
Example 1
200mg of nano N-TiO2The powder was added to 1L of water and different doses of PAFC were added, with rapid stirring at 250rpm for 1min and slow stirring at 40rpm for 20 min. Standing for 20min after coagulation, and determining N-TiO by detecting turbidity change of supernatant (2 cm below liquid level)2Whether the powder is completely coagulated. When the added PAFC is 20mg/L, the N-TiO2The powder was completely coagulated, see fig. 1.
Example 2
500mg of nano N-TiO2The powder was added to 1L of water and different doses of PAFC were added, with rapid stirring at 250rpm for 1min and slow stirring at 40rpm for 20 min. Standing for 20min after coagulation, and determining N-TiO by detecting turbidity change of supernatant (2 cm below liquid level)2Whether the powder is completely coagulated. When the added PAFC is 20mg/L, the N-TiO2The powder was completely coagulated, see fig. 1.
Example 3
1000mg of nano N-TiO2The powder was added to 1L of water and different doses of PAFC were added, with rapid stirring at 250rpm for 1min and slow stirring at 40rpm for 20 min. Standing for 20min after coagulation, and determining N-TiO by detecting turbidity change of supernatant (2 cm below liquid level)2Whether the powder is completely coagulated. When the PAFC added is 50mg/L, the N-TiO2The powder was completely coagulated, see fig. 1.
In conclusion, according to the principle of coagulant saving, 500mg of nano N-TiO is selected2The powder was added to 1L of water and 20mg/L of PAFC was added as optimum coagulation conditions.
Example 4
Removing supernatant from the coagulated system, centrifuging the rest part (4000rpm, 5min), removing supernatant, and collecting the rest part as nanometer N-TiO2A floc.
Collecting 1g of nano N-TiO2The coagulated flocs were added to 100mL of 0.01mM methyl orange solution, stirred at 1000rpm, and given 20000lux of visible light intensity, and after 20 hours, the degradation rate of the methyl orange solution was 69%, as shown in FIG. 2.
Example 5
Removing supernatant from the coagulated system, centrifuging the rest part (4000rpm, 5min), removing supernatant, and collecting the rest part as nanometer N-TiO2A floc.
Collecting 3g of nano N-TiO2The coagulated flocs were added to 100mL of 0.01mM methyl orange solution, stirred at 1000rpm, and given 20000lux of visible light intensity, and after 20 hours, the degradation rate of the methyl orange solution was 86.5%, as shown in FIG. 2.
Example 6
Removing supernatant from the coagulated system, centrifuging the rest part (4000rpm, 5min), removing supernatant, and collecting the rest part as nanometer N-TiO2A floc.
5g of nano N-TiO was collected2The coagulated flocs were added to 100mL of 0.01mM methyl orange solution, stirred at 1000rpm, and given 20000lux of visible light intensity, and after 20 hours, the degradation rate of the methyl orange solution was 100%, as shown in FIG. 2.
In conclusion, 5g of nano N-TiO is selected to improve the degradation efficiency of methyl orange2The flocculated powder was added to a solution of 100mL, 0.01mM methyl orange for optimal degradation.
Example 7
When the grain size is 5g of nano N-TiO2After the floc after the powder coagulation is degraded, centrifuging the system (4000rpm, 5min), discarding the upper liquid, and taking the rest part as the recovered nano N-TiO2A floc.
5g of recovered nano N-TiO2The coagulated flocs were added to 100mL of 0.01mM methyl orange solution again, stirred at 1000rpm, and given 20000lux of visible light intensity, and after 20 hours, the degradation rate of the methyl orange solution was 95.5%, as shown in FIG. 3.
Repeating the above steps againUsing nano N-TiO2The degradation rate of the flocs used for the third time is 91%.
In conclusion, the nano N-TiO2The floc can be recycled for a plurality of times, and the degradation efficiency is only slightly reduced. Therefore, the operation cost of the process can be greatly reduced.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (11)
1. A method for degrading water pollutants by using nano photocatalyst flocs is characterized by comprising the following steps: the method comprises the following steps:
1) adding the nano photocatalyst into water for uniform dispersion, then adding a coagulant into the water, stirring the mixture to finish coagulation, and forming nano photocatalyst flocs in the coagulation process; the nano photocatalyst is nano nitrogen-doped titanium dioxide, and the coagulant is polyaluminium ferric chloride;
2) after the coagulation is finished, separating out the generated floc to obtain nano photocatalyst floc;
3) adding the nano photocatalyst flocs obtained in the step 2) into the wastewater to be treated, and irradiating the wastewater under visible light to complete the photocatalytic degradation of pollutants in the wastewater.
2. The method of claim 1, wherein: in the step 1), the mass ratio of the nano nitrogen-doped titanium dioxide to the polyaluminum ferric chloride is 20-100: 1-5.
3. The method of claim 2, wherein: in the step 1), the mass ratio of the nano nitrogen-doped titanium dioxide to the polyaluminum ferric chloride is 20-30: 1.
4. The method of claim 1, wherein: in the step 2), after coagulation is completed, standing the reaction system, discarding supernatant when the flocs are completely settled to the bottom, and centrifuging the rest to obtain the nano photocatalyst flocs.
5. The method of claim 4, wherein: in the step 2), the standing time is 5-60 min.
6. The method of claim 4, wherein: in the step 2), the rotation speed during centrifugation is 2000-5000rpm, and the centrifugation time is 5-10 min.
7. The method of claim 1, wherein: in the step 3), the intensity of visible light illumination is 3000-15000 Lux.
8. The method of claim 1, wherein: in the step 1), the stirring speed of the nano photocatalyst is 150-250rpm when the nano photocatalyst is uniformly dispersed in water, and the stirring time is 1-2 min; the stirring speed during coagulation is 30-60rpm, and the stirring time is 10-20 min.
9. The method of claim 1, wherein: the preparation method of the nano nitrogen-doped titanium dioxide comprises the following steps: 12-18 parts of butyl titanate, 18-22 parts of absolute ethyl alcohol, 0.05-0.5 part of urea and 28-35 parts of dilute nitric acid solution by weight are mixed, heated for 3-5 hours at 80-100 ℃, and then calcined for 3-5 hours at 400-500 ℃ to obtain white powder, namely the nano nitrogen-doped titanium dioxide.
10. The method of claim 9, wherein: the preparation method of the nano nitrogen-doped titanium dioxide comprises the following steps:
1) mixing butyl titanate and absolute ethyl alcohol to obtain a solution A, and dissolving urea in a dilute nitric acid solution to obtain a solution B;
2) and slowly adding the solution A into the solution B under the stirring condition, adjusting the pH value of the solution to be neutral, heating for reaction, and then calcining to obtain the nano nitrogen-doped titanium dioxide.
11. Use of the method for degrading water pollutants by using nano photocatalyst flocs as claimed in any one of claims 1 to 10 in the degradation of domestic sewage or industrial wastewater.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711396046.XA CN108147496B (en) | 2017-12-21 | 2017-12-21 | Method for degrading water pollutants by using nano photocatalyst flocs |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711396046.XA CN108147496B (en) | 2017-12-21 | 2017-12-21 | Method for degrading water pollutants by using nano photocatalyst flocs |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108147496A CN108147496A (en) | 2018-06-12 |
| CN108147496B true CN108147496B (en) | 2020-06-05 |
Family
ID=62464863
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711396046.XA Active CN108147496B (en) | 2017-12-21 | 2017-12-21 | Method for degrading water pollutants by using nano photocatalyst flocs |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108147496B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112174279B (en) * | 2020-11-13 | 2022-08-02 | 陕西科技大学 | Polymeric aluminosilicate inorganic flocculant and preparation method and application thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101928049A (en) * | 2010-08-24 | 2010-12-29 | 华南理工大学 | Method for performing photocatalytic treatment on organic pollutant effluents by nanometer titania colloid |
| CN104117360A (en) * | 2014-07-10 | 2014-10-29 | 青岛润国生态科技发展有限公司 | Preparation method of flocculation-photocatalysis composite powder |
| CN104492469A (en) * | 2014-12-04 | 2015-04-08 | 常州大学 | Preparation method of iron-nitrogen doped titanium dioxide composite photo-catalyst |
| CN107140719A (en) * | 2017-05-18 | 2017-09-08 | 山东大学 | Strengthen algae coagulation using nitrogen-doped titanium dioxide while the method for the bed mud containing algae of degrading under visible light |
| CN107235531A (en) * | 2017-06-27 | 2017-10-10 | 福建省农业科学院农业工程技术研究所 | A kind of modifying titanium dioxide chelates the purifying agent for polluted water of poly aluminium iron silicate |
-
2017
- 2017-12-21 CN CN201711396046.XA patent/CN108147496B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101928049A (en) * | 2010-08-24 | 2010-12-29 | 华南理工大学 | Method for performing photocatalytic treatment on organic pollutant effluents by nanometer titania colloid |
| CN104117360A (en) * | 2014-07-10 | 2014-10-29 | 青岛润国生态科技发展有限公司 | Preparation method of flocculation-photocatalysis composite powder |
| CN104492469A (en) * | 2014-12-04 | 2015-04-08 | 常州大学 | Preparation method of iron-nitrogen doped titanium dioxide composite photo-catalyst |
| CN107140719A (en) * | 2017-05-18 | 2017-09-08 | 山东大学 | Strengthen algae coagulation using nitrogen-doped titanium dioxide while the method for the bed mud containing algae of degrading under visible light |
| CN107235531A (en) * | 2017-06-27 | 2017-10-10 | 福建省农业科学院农业工程技术研究所 | A kind of modifying titanium dioxide chelates the purifying agent for polluted water of poly aluminium iron silicate |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108147496A (en) | 2018-06-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU2017414238B2 (en) | Method for enhancing algae coagulation using nitrogen-doped titanium dioxide and degrading algae-containing sediment in visible light simultaneously | |
| AU2017414754B2 (en) | Algae-removing coagulant for enhancing algae coagulation and degrading algae-containing sediment in visible light simultaneously, preparation method therefor and application thereof | |
| CN105967294A (en) | Defluorination flocculation reaction method for fluorine-containing wastewater | |
| CN110040878A (en) | A kind of fluoride waste deep treatment method | |
| CN105084589A (en) | Treatment method and system for wet magnesium desulphurization wastewater | |
| US8083950B2 (en) | Methods for recovering organic-inorganic element-doped metal oxides from hydrolysable metal compounds associated with contaminated water treatment | |
| Jin et al. | Using photocatalyst powder to enhance the coagulation and sedimentation of cyanobacterial cells and enable the sludge to be self-purified under visible light | |
| CN108147496B (en) | Method for degrading water pollutants by using nano photocatalyst flocs | |
| CN1275881C (en) | Method for photo-oxidative flocculating treatment of organic pollutant waster water | |
| JP4272122B2 (en) | Coagulated water treatment method and apparatus | |
| JP2005199248A (en) | Raw water treatment process | |
| CN107935269B (en) | Water treatment process capable of recycling coagulant and photocatalytic material and realizing zero discharge of muddy water | |
| JP2004267855A (en) | Water treatment apparatus utilizing photocatalyst | |
| CN103464132A (en) | Multiplex photo-catalyst based on flocculation sludge water treatment and preparing method of multiplex photo-catalyst | |
| CN209583860U (en) | A kind of hybrid apparatus for treating carbonized waste water | |
| CN209024323U (en) | A kind of power plant's lime stone-gypsum wet desulfurization wastewater treatment system | |
| JP2010058048A (en) | Method for treating fluorine-containing wastewater using titanium oxide and metatitanic acid | |
| CN111995016A (en) | Coagulant for removing humic acid and preparation method and application thereof | |
| Wern et al. | Coagulation performance of titanium tetrachloride for Alor Pongsu wastewater treatment | |
| JP2000301161A (en) | Flocculation treatment of water and utilization of flocculated sludge | |
| CN217202400U (en) | Concentrated decrement system of strong brine | |
| Van Suc | Photocatalytic degradation of 1: 2 metal complex dye Acid blue 193 under solar light condition using ZnO nanoneedles and ZnO/bentonite nanocomposite synthesized via microwave irradiation | |
| CN109231388B (en) | Preparation method of nano flocculant with recyclable floc, product and application thereof | |
| Atikah et al. | The potential use of titanium tetracloride (TiCl4) as an alternative for coagulant in textile wastewater treatment | |
| Zhang et al. | TiO 2 base coagulant and its application |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |