CN110918099A - Method for treating wastewater containing hexavalent chromium by photocatalytic reduction of nickel oxide-nickel cobaltate-black titanium dioxide composite - Google Patents
Method for treating wastewater containing hexavalent chromium by photocatalytic reduction of nickel oxide-nickel cobaltate-black titanium dioxide composite Download PDFInfo
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- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims abstract description 294
- 239000004408 titanium dioxide Substances 0.000 title claims abstract description 182
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 title claims abstract description 139
- WZOZCAZYAWIWQO-UHFFFAOYSA-N [Ni].[Ni]=O Chemical compound [Ni].[Ni]=O WZOZCAZYAWIWQO-UHFFFAOYSA-N 0.000 title claims abstract description 126
- 239000002351 wastewater Substances 0.000 title claims abstract description 102
- 230000001699 photocatalysis Effects 0.000 title claims abstract description 76
- 239000002131 composite material Substances 0.000 title claims abstract description 42
- 238000000034 method Methods 0.000 title claims abstract description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 68
- 239000008367 deionised water Substances 0.000 claims abstract description 64
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 64
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims abstract description 47
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims abstract description 47
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims abstract description 30
- 239000000725 suspension Substances 0.000 claims abstract description 30
- QGUAJWGNOXCYJF-UHFFFAOYSA-N cobalt dinitrate hexahydrate Chemical compound O.O.O.O.O.O.[Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O QGUAJWGNOXCYJF-UHFFFAOYSA-N 0.000 claims abstract description 19
- AOPCKOPZYFFEDA-UHFFFAOYSA-N nickel(2+);dinitrate;hexahydrate Chemical compound O.O.O.O.O.O.[Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O AOPCKOPZYFFEDA-UHFFFAOYSA-N 0.000 claims abstract description 18
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000004202 carbamide Substances 0.000 claims abstract description 15
- 239000000843 powder Substances 0.000 claims abstract description 15
- 239000007795 chemical reaction product Substances 0.000 claims description 75
- 238000003756 stirring Methods 0.000 claims description 69
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 52
- 239000011259 mixed solution Substances 0.000 claims description 52
- 229910052724 xenon Inorganic materials 0.000 claims description 43
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 claims description 43
- 239000000243 solution Substances 0.000 claims description 40
- 239000011265 semifinished product Substances 0.000 claims description 39
- 238000001035 drying Methods 0.000 claims description 38
- 229910000033 sodium borohydride Inorganic materials 0.000 claims description 29
- 239000012279 sodium borohydride Substances 0.000 claims description 29
- 238000007146 photocatalysis Methods 0.000 claims description 28
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 26
- 239000011521 glass Substances 0.000 claims description 26
- 239000000047 product Substances 0.000 claims description 26
- 239000007788 liquid Substances 0.000 claims description 25
- 238000001354 calcination Methods 0.000 claims description 16
- 239000012298 atmosphere Substances 0.000 claims description 13
- 238000001914 filtration Methods 0.000 claims description 13
- 239000012535 impurity Substances 0.000 claims description 13
- 229910001410 inorganic ion Inorganic materials 0.000 claims description 13
- 238000002798 spectrophotometry method Methods 0.000 claims description 13
- 238000007789 sealing Methods 0.000 claims description 12
- 238000005406 washing Methods 0.000 claims description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 8
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 2
- 238000005119 centrifugation Methods 0.000 claims description 2
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 239000011651 chromium Substances 0.000 claims description 2
- 239000007864 aqueous solution Substances 0.000 claims 1
- OQUOOEBLAKQCOP-UHFFFAOYSA-N nitric acid;hexahydrate Chemical compound O.O.O.O.O.O.O[N+]([O-])=O OQUOOEBLAKQCOP-UHFFFAOYSA-N 0.000 claims 1
- 239000012299 nitrogen atmosphere Substances 0.000 claims 1
- 239000000203 mixture Substances 0.000 abstract description 15
- 230000007613 environmental effect Effects 0.000 abstract description 4
- UMTMDKJVZSXFNJ-UHFFFAOYSA-N nickel;trihydrate Chemical compound O.O.O.[Ni] UMTMDKJVZSXFNJ-UHFFFAOYSA-N 0.000 abstract description 3
- KSPIHGBHKVISFI-UHFFFAOYSA-N Diphenylcarbazide Chemical compound C=1C=CC=CC=1NNC(=O)NNC1=CC=CC=C1 KSPIHGBHKVISFI-UHFFFAOYSA-N 0.000 abstract description 2
- 239000012456 homogeneous solution Substances 0.000 abstract 1
- -1 titanium dioxide compound Chemical class 0.000 description 85
- 238000004140 cleaning Methods 0.000 description 37
- 238000006722 reduction reaction Methods 0.000 description 18
- 238000006243 chemical reaction Methods 0.000 description 13
- 238000010438 heat treatment Methods 0.000 description 12
- 230000001678 irradiating effect Effects 0.000 description 12
- 238000005303 weighing Methods 0.000 description 12
- 238000000227 grinding Methods 0.000 description 11
- 238000001000 micrograph Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 208000005623 Carcinogenesis Diseases 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- 241000282414 Homo sapiens Species 0.000 description 1
- 241001465754 Metazoa Species 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000036952 cancer formation Effects 0.000 description 1
- 231100000504 carcinogenesis Toxicity 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 238000003760 magnetic stirring Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000011941 photocatalyst Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
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- 231100000419 toxicity Toxicity 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000000844 transformation Methods 0.000 description 1
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- 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
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
- B01J35/39—Photocatalytic properties
-
- 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
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
- B01J23/74—Iron group metals
- B01J23/755—Nickel
-
- 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
-
- 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
- C02F1/70—Treatment of water, waste water, or sewage by reduction
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
- C02F2101/22—Chromium or chromium compounds, e.g. chromates
-
- 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
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- Engineering & Computer Science (AREA)
- Hydrology & Water Resources (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Materials Engineering (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Health & Medical Sciences (AREA)
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- Treatment Of Water By Oxidation Or Reduction (AREA)
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Abstract
本发明涉及一种氧化镍‑钴酸镍‑黑二氧化钛复合物光催化还原处理含六价铬废水的方法，先制备黑色二氧化钛，取六水合硝酸钴、六水合硝酸镍、黑二氧化钛，将其溶解在适量去离子水，磁力搅拌形成均匀的溶液，向其中添加适量聚乙烯吡咯烷酮（PVP，K30），然后将悬浮液搅拌磁力搅拌器至少1小时。将尿素分散到悬浮液中，将粉末研碎于管式炉中500度空气中煅烧两小时得到氧化镍‑钴酸镍‑黑二氧化钛复合物。将氧化镍‑钴酸镍‑黑二氧化钛复合物加入含六价铬废水中。以一定的时间间隔取出混合物，并立即过滤，通过紫外可见分光光度计根据1,5‑二苯卡巴肼法在540nm处进行测定处理后的六价铬浓度并计算去除率。该发明具有去除率高、处理成本低且环境友好等优点。
The invention relates to a method for treating wastewater containing hexavalent chromium by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite. First, black titanium dioxide is prepared, cobalt nitrate hexahydrate, nickel nitrate hexahydrate and black titanium dioxide are taken and dissolved. In an appropriate amount of deionized water, magnetically stirred to form a homogeneous solution, to which an appropriate amount of polyvinylpyrrolidone (PVP, K30) was added, and then the suspension was stirred with a magnetic stirrer for at least 1 hour. The urea was dispersed in the suspension, the powder was pulverized and calcined in a tube furnace at 500 degrees for two hours to obtain a nickel oxide-nickel cobaltate-black titanium dioxide composite. The nickel oxide-nickel cobaltate-black titanium dioxide composite was added to the wastewater containing hexavalent chromium. The mixture was taken out at certain time intervals and filtered immediately, and the concentration of hexavalent chromium after treatment was measured at 540 nm by the UV-Vis spectrophotometer according to the 1,5-diphenylcarbazide method and the removal rate was calculated. The invention has the advantages of high removal rate, low treatment cost and environmental friendliness.
Description
Technical Field
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, belonging to the technical field of sewage treatment.
Background
In recent years, with the increasing awareness of the public on environmental protection, various new water treatment technologies have been developed. The photocatalytic technology is considered to be one of new water treatment technologies with great development potential. Due to the characteristics of direct utilization of sunlight, environmental friendliness and the like, the solar cell has been receiving more and more attention. The explosive development of the metallurgical and mining industries causes the increasing amount of waste water containing heavy metal hexavalent chromium discharged into the environment, and poses a great threat to the environment. The hexavalent chromium-containing wastewater is difficult to biodegrade after being discharged into a water body, and can cause potential harm and even carcinogenesis to aquatic animals, plants and human beings. And the hexavalent chromium can be reduced by photocatalysis to effectively reduce the toxicity of the chromium.
Compared with other semiconductor photocatalytic materials, titanium dioxide which has biochemical inertia, strong oxidation capability, no toxicity and is not easily influenced by light and chemical corrosion is always the most widely researched photocatalyst. However, the photocatalytic efficiency of titanium dioxide is limited by the rate of rapid recombination of photo-generated electrons and holes. Moreover, anatase titanium dioxide having a large band gap (-3.2 eV) can only be excited by ultraviolet light, which significantly limits the solar energy utilization. Therefore, narrowing the band gap of anatase titanium dioxide to extend the photoresponse to the visible region is critical to improve solar driven photocatalytic processes. We have therefore made black titanium dioxide. Nickel cobaltate is a common metal oxide, and has been proved by a plurality of literatures to have stronger catalytic activity; in order to effectively improve the specific surface area of the material, the nickel cobaltate and the black titanium dioxide are compounded, and the catalyst has higher catalytic activity on oxygen reduction reaction.
Disclosure of Invention
The invention aims to overcome the problems in the prior art and provide a treatment method of hexavalent chromium-containing wastewater, in particular to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, wherein the composite has excellent visible light photocatalytic performance.
The invention aims to realize the method for treating the hexavalent chromium-containing wastewater by the photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which is characterized by comprising the following steps of:
⑴ grinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) uniformly (mass ratio is 2-3) in N2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeatedly washing with hydrochloric acid and deionized water, centrifugally collecting, and drying a full-black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑻ adding 5-10 mg of nickel oxide-nickel cobaltate-black titanium dioxide compound finished product into 30mL of hexavalent chromium-containing wastewater to obtain hexavalent chromium-containing wastewater containing the nickel oxide-nickel cobaltate-black titanium dioxide compound, wherein the initial concentration C of hexavalent chromium in the hexavalent chromium-containing wastewater is03-10 mg/L, and the pH value is 4.01-6.93;
⑼ adding the hexavalent chromium-containing wastewater containing the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑻ into a glass container, and sealing;
⑽, putting the glass container in step ⑼ into a dark box of a photocatalytic reactor, stirring for 30-60 minutes, and controlling the temperature to be 25 ℃;
⑾, after the stirring is finished, turning on a xenon lamp, irradiating the hexavalent chromium-containing wastewater containing the nickel oxide-nickel cobaltate-black titanium dioxide compound for 120 minutes under the xenon lamp, wherein the power of the xenon lamp is 400W, extracting 5mL of hexavalent chromium-containing wastewater in the photocatalysis process at certain time intervals, and filtering;
⑿ taking 2mL of clear liquid, and measuring the concentration C of the treated hexavalent chromium by using an ultraviolet spectrophotometrye；
The removal rate after photocatalysis was calculated as (C/C)0)*100％。(C＝C0-Ce)；
C0The initial concentration of hexavalent chromium in the hexavalent chromium-containing wastewater is expressed in unit mg/L; ceThe unit of the concentration of hexavalent chromium in the treated wastewater containing hexavalent chromium is mg/L; c is the concentration of the degraded hexavalent chromium and has the unit of mg/L.
In step ⑴, the mass ratio of P25 to NaBH4 is 2, and P25 and NaBH4 are in N2The calcination temperature in the atmosphere was 350 ℃.
In steps ⑵ and ⑶, the stirring frequency of cobalt nitrate hexahydrate, nickel nitrate hexahydrate and black titanium dioxide is not lower than 200 revolutions per minute, wherein the cobalt nitrate hexahydrate is 2.5mmol, the nickel nitrate hexahydrate is 7.5mmol, and the black titanium dioxide is 2.5 mmol.
In step ⑶, 0.8g of polyvinylpyrrolidone (PVP, K30) was added.
In step ⑺, the calcination temperature was 500 ℃.
Compared with the prior art, the invention has the following beneficial effects:
① the mass ratio must be controlled within a suitable range to obtain black titanium dioxide in step ⑴.
② the black titanium dioxide is added into the nickel oxide-nickel cobaltate synthesis system to improve the structure of the black titanium dioxide, and promote the black titanium dioxide compound to have larger specific surface area and wider visible light utilization area.
③ the weight ratio of the black titanium dioxide to the nickel cobaltate in the nickel oxide-nickel cobaltate-black titanium dioxide compound prepared by the invention is about (0.2-2): 1, the compound has excellent performance of reducing hexavalent chromium in water by photocatalysis, the cost is low, the compound has high photocatalysis removal rate when used for reducing wastewater containing hexavalent chromium, and has high potential industrial application value, when the hexavalent chromium-containing wastewater with initial concentration of 3-7 mg/L and pH value of 4-6 is put into 30mL wastewater according to 3-10 mg of the nickel oxide-nickel cobaltate-black titanium dioxide compound, the removal rate can reach more than 70% after the xenon lamp irradiates for 30-120 minutes.
④ for waste water containing hexavalent chromium with initial concentration of 3mg/L and pH value of 5.01, 6mg of nickel oxide-nickel cobaltate-black titanium dioxide compound is put into 30mL of waste water, and hexavalent chromium can be reduced basically by xenon lamp irradiation for more than 120 minutes, for waste water containing hexavalent chromium with initial concentration of 7mg/L and pH value of 5.01, 6mg of nickel oxide-nickel cobaltate-black titanium dioxide compound is put into 30mL of waste water, and hexavalent chromium is reduced by more than 70% after xenon lamp irradiation for 120 minutes.
In summary, the invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite. The method comprises the following steps: preparing black titanium dioxide nanoparticles by a simple NaBH 4-assisted method, preparing black titanium dioxide, dissolving a certain amount of cobalt nitrate hexahydrate, nickel nitrate hexahydrate and black titanium dioxide in a proper amount of deionized water, carrying out magnetic stirring to form a uniform solution, adding a proper amount of polyvinylpyrrolidone (PVP, K30) while stirring, and then stirring the suspension for at least 1 hour by a magnetic stirrer. And then dispersing a certain amount of urea into the suspension, reacting in a high-pressure reaction kettle for several hours, cooling, centrifuging to obtain a precipitate, cleaning for several times, drying in an oven for overnight, grinding the powder in a tube furnace, and calcining in 500-DEG air for two hours to obtain the nickel oxide-nickel cobaltate-black titanium dioxide compound. Adding a certain amount of nickel oxide-nickel cobaltate-black titanium dioxide compound into hexavalent chromium wastewater with the initial concentration of 3-10 mg/L, and shaking the mixture in a constant-temperature oscillator under the condition of certain pH and temperature under the illumination condition. Subsequently, the mixture was taken out at regular intervals and immediately filtered, and the concentration of hexavalent chromium after the treatment was measured at 540nm by an ultraviolet-visible spectrophotometer according to the 1, 5-diphenylcarbazide method and the removal rate was calculated. The nickel oxide-nickel cobaltate-black titanium dioxide compound is used for treating hexavalent chromium-containing wastewater through photocatalytic reduction, and has the advantages of high removal rate, low treatment cost, environmental friendliness and the like.
Drawings
FIG. 1 is a scanning electron microscope image of a nickel oxide-nickel cobaltate-black titanium dioxide composite of example 1 of the present invention.
FIG. 2 is a scanning electron microscope image of the nickel oxide-nickel cobaltate-black titanium dioxide composite of example 5.
FIG. 3 is a scanning electron microscope image of the nickel oxide-nickel cobaltate-black titanium dioxide composite of example 8.
FIG. 4 is a scanning electron microscope image of the nickel oxide-nickel cobaltate-black titanium dioxide composite of example 10.
FIG. 5 is a graph showing the effect of different qualities of nickel oxide-nickel cobaltate-black titanium dioxide composite in photocatalytic hexavalent chromium in accordance with the present invention.
FIG. 6 is a graph showing the effect of the nickel oxide-nickel cobaltate-black titanium dioxide composite of the present invention in photocatalytic hexavalent chromium as a function of the pH of the solution.
Detailed Description
Example 1
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ grinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) uniformly (mass ratio is 2-3) in N2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeatedly washing with hydrochloric acid and deionized water, centrifugally collecting, and drying a full-black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
the hexavalent chromium-containing wastewater is photocatalytic by adopting the nickel oxide-nickel cobaltate-black titanium dioxide compound of the invention according to the following steps of ⑴Adding 6mg of nickel oxide-nickel cobaltate-black titanium dioxide compound finished product into 30mL of hexavalent chromium-containing wastewater, wherein the initial concentration C of hexavalent chromium in the hexavalent chromium-containing wastewater03mg/L, pH value of 4.32, ⑵ adding hexavalent chromium-containing wastewater of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑴ into a glass container, sealing, ⑶ placing the glass container in the step ⑵ into a dark box of a photocatalytic reactor, stirring for 30 minutes, controlling the temperature to be 25 ℃, after the stirring of ⑷ is finished, turning on a xenon lamp, irradiating the solid-liquid mixture in the step ⑶ for 30 to 120 minutes under the xenon lamp, controlling the power of the xenon lamp to be 400W, after the completion of ⑸ photocatalysis, extracting 5mL of hexavalent chromium-containing wastewater in the step ⑷, filtering, taking 2mL of clear liquid from ⑹, and measuring the concentration C of the treated hexavalent chromium by an ultraviolet spectrophotometry methode0.0mg/L, ⑺ calculating the removal rate after photocatalysis is 1- (C)e/C0)*100％＝100％。
Example 2
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ grinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) uniformly (mass ratio is 2-3) in N2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeatedly washing with hydrochloric acid and deionized water, centrifugally collecting, and drying a full-black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain the finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound.
⑴ adding 6mg of finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound into 30mL of waste water containing hexavalent chromium, wherein the initial concentration C of hexavalent chromium in the waste water containing hexavalent chromium is03mg/L, pH value of 5.01, ⑵ adding the hexavalent chromium-containing wastewater of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑴ into a glass container, sealing, ⑶ placing the glass container of the step ⑵ into a dark box of a photocatalytic reactor, stirring for 30 minutes, controlling the temperature to be 25 ℃, after the stirring of ⑷ is finished, turning on a xenon lamp, irradiating the solid-liquid mixture of the step ⑶ for 30 to 120 minutes under the xenon lamp, controlling the power of the xenon lamp to be 400W, after the photocatalysis of ⑸ is finished, extracting 5mL of the hexavalent chromium-containing wastewater of the step ⑷, filtering, taking 2mL of clear liquid of ⑹, and measuring the concentration C of the treated hexavalent chromium by an ultraviolet spectrophotometry methode0.0mg/L, ⑺ calculating the removal rate after photocatalysis is 1- (C)e/C0)*100％＝100％。
Example 3
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ uniformityGrinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) (the mass ratio is 2-3) in N2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeatedly washing with hydrochloric acid and deionized water, centrifugally collecting, and drying a full-black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
the hexavalent chromium-containing wastewater is photocatalytic by adopting the nickel oxide-nickel cobaltate-black titanium dioxide compound of the invention according to the following steps that ⑴ mg of the finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound is added into 30mL of hexavalent chromium-containing wastewaterIn the hexavalent chromium wastewater, the initial concentration C of hexavalent chromium in the hexavalent chromium wastewater03mg/L, pH 6.44, ⑵ adding the hexavalent chromium-containing wastewater of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑴ into a glass container, sealing, ⑶ placing the glass container of the step ⑵ into a dark box of a photocatalytic reactor, stirring for 30 minutes, controlling the temperature to be 25 ℃, after the stirring of ⑷ is finished, turning on a xenon lamp, irradiating the solid-liquid mixture of the step ⑶ for 30 to 120 minutes under the xenon lamp, wherein the power of the xenon lamp is 400W, after the end of ⑸ photocatalysis, extracting 5mL of the hexavalent chromium-containing wastewater of the step ⑷, filtering, taking 2mL of clear liquid of ⑹, and measuring the concentration C of the treated hexavalent chromium by an ultraviolet spectrophotometry methode0.063mg/L, ⑺ calculating the removal rate after photocatalysis is 1- (C)e/C0)*100％＝97.9％。
Example 4
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ grinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) uniformly (mass ratio is 2-3) in N2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeatedly washing with hydrochloric acid and deionized water, centrifugally collecting, and drying a full-black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑴ adding 6mg of finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound into 30mL of waste water containing hexavalent chromium, wherein the initial concentration C of hexavalent chromium in the waste water containing hexavalent chromium is03mg/L, pH 7.13, ⑵ adding the hexavalent chromium-containing wastewater of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑴ into a glass container, sealing, ⑶ placing the glass container of the step ⑵ into a dark box of a photocatalytic reactor, stirring for 30 minutes, controlling the temperature to be 25 ℃, after the stirring of ⑷ is finished, turning on a xenon lamp, irradiating the solid-liquid mixture of the step ⑶ for 30 to 120 minutes under the xenon lamp, controlling the power of the xenon lamp to be 400W, after the completion of ⑸ photocatalysis, extracting 5mL of the hexavalent chromium-containing wastewater of the step ⑷, filtering, taking 2mL of clear liquid of ⑹, and measuring the concentration C of the treated hexavalent chromium by an ultraviolet spectrophotometry methodeIs 0.227mg/L, and ⑺ is used to calculate the removal rate after photocatalysis is 1- (C)e/C0)*100％＝92.4％。
Example 5
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ commercial titanium dioxide (P25) and sodium borohydride (NaBH4) (mass ratio 2 to E ℃)3) In N at2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeatedly washing with hydrochloric acid and deionized water, centrifugally collecting, and drying a full-black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑴ mg of finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound is added into 30mL of waste water containing hexavalent chromium, and the hexavalent chromium of the waste water containing hexavalent chromium is initially concentratedDegree C03mg/L, pH value of 5.01, ⑵ adding the hexavalent chromium-containing wastewater of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑴ into a glass container, sealing, ⑶ placing the glass container of the step ⑵ into a dark box of a photocatalytic reactor, stirring for 30 minutes, controlling the temperature to be 25 ℃, after the stirring of ⑷ is finished, turning on a xenon lamp, irradiating the solid-liquid mixture of the step ⑶ for 30 to 120 minutes under the xenon lamp, controlling the power of the xenon lamp to be 400W, after the photocatalysis of ⑸ is finished, extracting 5mL of the hexavalent chromium-containing wastewater of the step ⑷, filtering, taking 2mL of clear liquid of ⑹, and measuring the concentration C of the treated hexavalent chromium by an ultraviolet spectrophotometry methode0.908mg/L, ⑺ calculating the removal rate after photocatalysis is 1- (C)e/C0)*100％＝69.7％。
Example 6
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ grinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) uniformly (mass ratio is 2-3) in N2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeatedly washing with hydrochloric acid and deionized water, centrifugally collecting, and drying a full-black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑴ adding 5mg of finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound into 30mL of waste water containing hexavalent chromium, wherein the initial concentration C of hexavalent chromium in the waste water containing hexavalent chromium is03mg/L, pH value of 5.01, ⑵ adding the hexavalent chromium-containing wastewater of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑴ into a glass container, sealing, ⑶ placing the glass container of the step ⑵ into a dark box of a photocatalytic reactor, stirring for 30 minutes, controlling the temperature to be 25 ℃, after the stirring of ⑷ is finished, turning on a xenon lamp, irradiating the solid-liquid mixture of the step ⑶ for 30 to 120 minutes under the xenon lamp, controlling the power of the xenon lamp to be 400W, after the photocatalysis of ⑸ is finished, extracting 5mL of the hexavalent chromium-containing wastewater of the step ⑷, filtering, taking 2mL of clear liquid of ⑹, and measuring the concentration C of the treated hexavalent chromium by an ultraviolet spectrophotometry methode0.155mg/L, ⑺ calculating the removal rate after photocatalysis is 1- (C)e/C0)*100％＝94.8％。
Example 7
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ grinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) uniformly (mass ratio is 2-3) in N2Heating the mixture for 2 hours at 300-400 ℃ in the atmosphereThe obtained all-black sample is 0.1mol L-1Repeatedly washing with hydrochloric acid and deionized water, centrifugally collecting, and drying a full-black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑴ mg of finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound is added into 30mL of waste water containing hexavalent chromium, and the initial concentration C of hexavalent chromium in the waste water containing hexavalent chromium is03mg/L, pH 5.01, ⑵ extracting ⑴Adding hexavalent chromium-containing wastewater of a nickel oxide-nickel cobaltate-black titanium dioxide compound into a glass container, sealing, ⑶ putting the glass container in the step ⑵ into a dark box of a photocatalytic reactor, stirring for 30 minutes, controlling the temperature to be 25 ℃, turning on a xenon lamp after ⑷ stirring is finished, irradiating the solid-liquid mixture in the step ⑶ for 30-120 minutes under the xenon lamp, controlling the power of the xenon lamp to be 400W, extracting 5mL of hexavalent chromium-containing wastewater in the step ⑷ after ⑸ photocatalysis is finished, filtering, taking 2mL of clear liquid, and measuring the concentration C of hexavalent chromium after treatment by using an ultraviolet spectrophotometry, wherein the concentration C of hexavalent chromium is measured by using ⑹e0.0mg/L, ⑺ calculating the removal rate after photocatalysis is 1- (C)e/C0)*100％＝100％。
Example 8
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ grinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) uniformly (mass ratio is 2-3) in N2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeatedly washing with hydrochloric acid and deionized water, centrifugally collecting, and drying a full-black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑴ mg of the finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound is added into 30mL of hexavalent chromium-containing wastewater, and the initial concentration C of hexavalent chromium in the hexavalent chromium-containing wastewater is03mg/L, pH value of 5.01, ⑵ adding the hexavalent chromium-containing wastewater of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑴ into a glass container, sealing, ⑶ placing the glass container of the step ⑵ into a dark box of a photocatalytic reactor, stirring for 30 minutes, controlling the temperature to be 25 ℃, after the stirring of ⑷ is finished, turning on a xenon lamp, irradiating the solid-liquid mixture of the step ⑶ for 30 to 120 minutes under the xenon lamp, controlling the power of the xenon lamp to be 400W, after the photocatalysis of ⑸ is finished, extracting 5mL of the hexavalent chromium-containing wastewater of the step ⑷, filtering, taking 2mL of clear liquid of ⑹, and measuring the concentration C of the treated hexavalent chromium by an ultraviolet spectrophotometry methode0.0mg/L, ⑺ calculating the removal rate after photocatalysis is 1- (C)e/C0)*100％＝100％。
Example 9
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ grinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) uniformly (mass ratio is 2-3) in N2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeated washing with hydrochloric acid and deionized waterWashing, centrifugally collecting, and drying the completely black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑴ adding 6mg of finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound into 30mL of waste water containing hexavalent chromium, wherein the initial concentration C of hexavalent chromium in the waste water containing hexavalent chromium is0⑵ adding the hexavalent chromium-containing wastewater of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑴ into the wastewater with the pH value of 5.01Sealing the glass container in ⑶, placing the glass container in ⑵ into a dark box of a photocatalytic reactor, stirring for 30 minutes, controlling the temperature to be 25 ℃, turning on a xenon lamp after ⑷ stirring is finished, irradiating the solid-liquid mixture in ⑶ for 30-120 minutes under the xenon lamp, wherein the power of the xenon lamp is 400W, extracting 5mL of hexavalent chromium-containing wastewater in ⑷ after ⑸ photocatalysis is finished, filtering, taking ⑹ 2mL of clear liquid, and measuring the concentration C of treated hexavalent chromium by an ultraviolet spectrophotometry methode0.568mg/L, ⑺ calculated the removal rate after photocatalysis is 1- (C)e/C0)*100％＝88.64％。
Example 10
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ grinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) uniformly (mass ratio is 2-3) in N2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeatedly washing with hydrochloric acid and deionized water, centrifugally collecting, and drying a full-black sample in a vacuum oven at 70 ℃ for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑴ adding 5mg of finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound into 30mL of waste water containing hexavalent chromium, wherein the initial concentration C of hexavalent chromium in the waste water containing hexavalent chromium is07mg/L, pH value of 5.01, ⑵ adding the hexavalent chromium-containing wastewater of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑴ into a glass container, sealing, ⑶ placing the glass container of the step ⑵ into a dark box of a photocatalytic reactor, stirring for 30 minutes, controlling the temperature to be 25 ℃, after the stirring of ⑷ is finished, turning on a xenon lamp, irradiating the solid-liquid mixture of the step ⑶ under the xenon lamp for 30-120 minutes, controlling the power of the xenon lamp to be 400W, after the photocatalysis of ⑸ is finished, extracting 5mL of the hexavalent chromium-containing wastewater of the step ⑷, filtering, taking 2mL of clear liquid of ⑹, and measuring the concentration C of the treated hexavalent chromium by an ultraviolet spectrophotometry methodeIs 1.886mg/L, and ⑺ calculates the removal rate after photocatalysis is 1- (C)e/C0)*100％＝73.1％。
Example 11
The invention relates to a method for treating hexavalent chromium-containing wastewater by photocatalytic reduction of a nickel oxide-nickel cobaltate-black titanium dioxide composite, which comprises the following steps:
⑴ grinding commercial titanium dioxide (P25) and sodium borohydride (NaBH4) uniformly (mass ratio is 2-3) in N2Heating at 300-400 ℃ for 2 hours in atmosphere, and using 0.1mol L of all-black sample-1Repeated washes with hydrochloric acid and deionized water and collection by centrifugation, then all black samples were taken at 70 deg.CDrying in a vacuum oven for 12 hours to obtain black titanium dioxide powder;
⑵ weighing 2-3 mmol of cobalt nitrate hexahydrate, 7-8 mmol of nickel nitrate hexahydrate and 2-3 mmol of black titanium dioxide, adding the three into 70 ml of deionized water solution, and placing the deionized water solution on a magnetic stirrer to stir for 30min until the solution is uniform to obtain a first mixed solution;
⑶ adding 0.5-1 g of polyvinylpyrrolidone (PVP, K30) into the first mixed solution obtained in the step ⑵, and continuously stirring for at least 1 hour to obtain a suspension;
⑷ adding 0.02mol of urea into the suspension obtained in the step ⑶, and continuously stirring for 30min to obtain a second mixed solution;
⑸ transferring the second mixed solution obtained in step ⑷ into a 100 ml high-pressure reaction kettle, and reacting for 7 hours at 180 ℃ to obtain a reaction product;
⑹, after centrifugally separating the reaction product obtained in the step ⑸ to remove moisture, firstly cleaning the reaction product with ethanol to remove unreacted polyvinylpyrrolidone, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, placing the cleaned reaction product in a drying oven, and drying the reaction product for 10 to 20 hours at 50 to 70 ℃ to obtain a semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑺, placing the semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in the step ⑹ into a tubular furnace, calcining for 2 hours at 400-500 ℃, and cleaning the calcined semi-finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound again by using ethanol and deionized water in sequence to remove impurities on the surface to obtain a finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound;
⑴ adding 5mg of finished product of the nickel oxide-nickel cobaltate-black titanium dioxide compound into 30mL of waste water containing hexavalent chromium, wherein the initial concentration C of hexavalent chromium in the waste water containing hexavalent chromium is010mg/L, pH 5.01, ⑵ adding the waste water containing hexavalent chromium of the nickel oxide-nickel cobaltate-black titanium dioxide compound obtained in step ⑴ into a glass container, sealing, ⑶ placing the glass container in step ⑵Stirring for 30 minutes in a dark box of a photocatalytic reactor, controlling the temperature to be 25 ℃, turning on a xenon lamp after the stirring of ⑷ is finished, irradiating the solid-liquid mixture obtained in the step ⑶ for 30 to 120 minutes under the xenon lamp, wherein the power of the xenon lamp is 400W, extracting 5mL of hexavalent chromium-containing wastewater obtained in the step ⑷ after the photocatalysis of ⑸ is finished, filtering, taking 2mL of clear liquid from ⑹, and measuring the concentration C of treated hexavalent chromium by an ultraviolet spectrophotometry methode6.985mg/L, ⑺ calculated the removal rate after photocatalysis 1- (C)e/C0)*100％＝30.2％。
The data for examples 1 to 11 are summarized in the table below, and the data for examples 2, 5, 6, 7, 8 are plotted in FIG. 5 and the data for examples 1 to 4 are plotted in FIG. 6.
From the summary table and fig. 6, it can be seen that, when 6mg of nickel oxide-nickel cobaltate-black titanium dioxide composite is added into 30mL of wastewater for hexavalent chromium-containing wastewater with an initial concentration of 3mg/L and a pH value of 4.32-7.13, the removal rate of the hexavalent chromium-containing wastewater exceeds 90% after xenon lamp irradiation for 120 minutes.
As can be seen from the summary table and fig. 6, the removal rate is gradually increased by increasing the dosage of the nickel oxide-nickel cobaltate-black titanium dioxide compound within a certain range under the same pH value; as can be seen from the summary table and FIG. 6, under the condition that the nickel oxide-nickel cobaltate-black titanium dioxide composite is the same, when the pH value is between 4.32 and 5.01, the removal rate is highest.
It is not stated that the percentages are by weight. The photocatalytic reactor can be a sh-yz-B type photocatalytic reactor of Shanghai Bilang laboratory instruments Co.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention. In addition to the above examples, the present invention may have other embodiments, for example, the mass and volume of each component may be scaled up several times. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention. Technical features of the present invention which are not described may be implemented by or using the prior art, and will not be described herein.
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| WO2021224576A1 (en) * | 2020-05-07 | 2021-11-11 | Centre National De La Recherche Scientifique | Method for preparing a supported metal catalyst, catalyst obtained according to this method and uses |
| CN114632536A (en) * | 2022-04-01 | 2022-06-17 | 吉林化工学院 | NiCo with photocatalytic properties2O4/NiO/g-C3N4Nanotube preparation method and application |
| CN115155597A (en) * | 2022-08-12 | 2022-10-11 | 洛阳理工学院 | Preparation method of recyclable nickel cobaltate/titania@AC@CFs photoelectric catalytic materials |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021224576A1 (en) * | 2020-05-07 | 2021-11-11 | Centre National De La Recherche Scientifique | Method for preparing a supported metal catalyst, catalyst obtained according to this method and uses |
| FR3109900A1 (en) * | 2020-05-07 | 2021-11-12 | Centre National De La Recherche Scientifique | Process for preparing a supported metal catalyst, catalyst obtained by this process and uses |
| CN114632536A (en) * | 2022-04-01 | 2022-06-17 | 吉林化工学院 | NiCo with photocatalytic properties2O4/NiO/g-C3N4Nanotube preparation method and application |
| CN114632536B (en) * | 2022-04-01 | 2023-10-20 | 吉林化工学院 | NiCo with photocatalytic properties 2 O 4 /NiO/g-C 3 N 4 Nanotube preparation method and application |
| CN115155597A (en) * | 2022-08-12 | 2022-10-11 | 洛阳理工学院 | Preparation method of recyclable nickel cobaltate/titania@AC@CFs photoelectric catalytic materials |
| CN115155597B (en) * | 2022-08-12 | 2023-07-18 | 洛阳理工学院 | Preparation method of recyclable nickel cobaltate/titanium dioxide@AC@CFs photocatalytic material |
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