Method for generating singlet oxygen by activating peroxydisulfate through hydroxyl-rich metal oxide
Technical Field
The invention relates to a method for generating singlet oxygen by activating peroxydisulfate with hydroxyl-rich metal oxide, belonging to the field of water treatment.
Background
Singlet oxygen (1O2) Is the lowest excited state of diatomic oxygen molecules, also called excited state oxygen molecules, and has different physical and chemical properties from diatomic oxygen molecules. Singlet oxygen is in a quantum state in which all electrons spin in pairs, is paramagnetic, is dynamically unstable at ambient temperature, and decays very slowly. The singlet oxygen has strong oxidability and good reactivity with organic compounds, and can be applied to organic synthesis and medicinesThe method comprises the following fields of synthesis, sterilization, disinfection, cancer treatment, environmental remediation, pollutant treatment and the like. Traces of singlet oxygen are present in the upper atmosphere and in polluted urban atmosphere, which contributes to the formation of nitrogen dioxide, which is harmful to the lungs.
Due to the high forbidden resistance of transition, the light absorption of the diatomic oxygen molecule in the ground state is impossible to directly generate singlet oxygen; singlet oxygen can be obtained by photosensitization methods, microwave discharge methods and chemical methods.
The photosensitization method is that the photosensitizer transits to an excited state under the condition of illumination, and then transfers energy to ground state oxygen molecules to form singlet oxygen. However, the method currently has the following problems: 1. the photosensitizer used generally is a toxic and harmful substance (such as porphyrin photosensitizer with high toxicity), so the application of the method in the fields of biomedicine, water treatment and the like is limited; 2. the photosensitizer used in the method is generally a water-soluble substance, which is not beneficial to subsequent separation; 3. when singlet oxygen is generated, the method is often accompanied with the generation of other active oxygen species (such as superoxide radical, hydroxyl radical and the like), and the singlet oxygen cannot be efficiently and directionally generated.
One commonly used chemical method is to decompose triethylsilyl hydroxide generated in situ from triethylsilane and ozone, further decomposing to obtain singlet oxygen, and the other is to react hydrogen peroxide with sodium hypochlorite in water. The prior common preparation method has the problems of inconvenient transportation of raw materials, high cost, inconvenient use, incapability of on-site preparation and the like.
Aiming at the defects of the existing photosensitization method and chemical method, a method which has low cost, convenient transportation and use, high efficiency, no toxicity and no harm and can generate singlet oxygen is needed to be developed.
Disclosure of Invention
Aiming at the defects of the existing photosensitization method and chemical method, the invention provides a method for generating singlet oxygen by activating peroxydisulfate with hydroxyl-rich metal oxide.
The invention achieves the following aims:
1. can quickly and efficiently generate singlet oxygen, does not generate other active oxygen species when generating the singlet oxygen, and can generate directionally.
2. The used activating agent is non-toxic and harmless, has no secondary pollution in reaction, low cost, convenient transportation and use and convenient subsequent separation.
In order to achieve the above purpose, the invention is realized by the following technical scheme:
a method for activating a hydrogen persulfate salt to generate singlet oxygen by a hydroxyl-rich metal oxide, comprising the steps of:
adding the hydroxyl-rich metal oxide and hydrogen persulfate into a solvent to obtain a mixed solution, and stirring the mixed solution at the temperature of between 10 and 30 ℃ for reaction, wherein the mass concentration of the hydroxyl-rich metal oxide in the mixed solution is as follows: 0.1-2.0 g/L, wherein the concentration of the hydrogen persulfate in the mixed solution is as follows: 0.20 to 5.00 mmol/L.
Preferably, according to the present invention, the hydroxyl-rich metal oxide is magnesium oxide, magnesium hydroxide, calcium hydroxide, aluminum hydroxide or zinc hydroxide.
Most preferably, the hydroxyl-rich metal oxide is magnesium oxide.
According to the invention, the preferred peroxodisulfate is oxone complex salt or sodium peroxodisulfate complex salt.
More preferably, the peroxodisulfate is a oxone complex salt.
According to the invention, the mixed solution preferably contains the following hydroxyl-rich metal oxides in mass concentration: 0.1-1.0 g/L, wherein the concentration of the hydrogen persulfate in the mixed solution is as follows: 0.20 to 4.00 mmol/L.
Further preferably, the mass concentration of the hydroxyl-rich metal oxide in the mixed solution is as follows: 0.4-1.0 g/L, wherein the concentration of the hydrogen persulfate in the mixed solution is as follows: 0.50 to 3.00 mmol/L.
According to the invention, the solvent is preferably water, alcohol-water or ether-water; the alcohol-water is methanol-water, ethanol-water or tert-butanol-water, and the ether-water is diethyl ether-water.
According to the present invention, the concentration of the alcohol or ether in the mixed solution is preferably: 200-5000 mmol/L.
Most preferably, the solvent is water.
In the invention, the reaction temperature is preferably 20-30 ℃.
In the present invention, the pH of the mixed solution is preferably 3.0 to 11.0.
More preferably, the pH of the mixed solution is 3.0 to 9.0.
Preferably, the reaction time is as follows: 0.5-2 h.
The invention preferably adopts a technical scheme that a method for generating singlet oxygen by activating peroxydisulfate with hydroxyl-rich metal oxide comprises the following steps:
adding the hydroxyl-rich metal oxide and the hydrogen persulfate into a water solvent, and stirring at 20-30 ℃ for reaction, wherein the pH of a reaction solution is 3.0-9.0, and the mass concentration of the hydroxyl-rich metal oxide in a mixed solution is as follows: 0.4-1.0 g/L, wherein the concentration of the hydrogen persulfate in the mixed solution is as follows: 0.50 to 3.00 mmol/L.
The principle of the hydroxyl-rich metal oxide activating the peroxydisulfate to generate singlet oxygen is as follows:
the hydroxyl-rich metal oxide is added into water, water molecules and the metal oxide are subjected to matching copolymerization, a large amount of hydroxyl is generated on the surface of the oxide, hydroxyl induces the peroxydisulfate to form a diepoxy intermediate, the diepoxy intermediate can be decomposed automatically to generate singlet oxygen, the generated singlet oxygen degrades pollutants to achieve the purpose of removing pollution, and the released hydroxyl-rich oxide continuously catalyzes the peroxydisulfate to realize the circulating catalysis effect.
The raw materials and equipment used in the invention are all the prior art.
The invention has the following advantages:
1. according to the method, the generation of singlet oxygen is immediately started at the beginning of the reaction, and no other active oxygen species are generated in the whole reaction process, so that the efficient and directional generation of the singlet oxygen is realized;
2. when the singlet oxygen is generated, the method does not need to add any toxic and harmful substance, and the whole reaction process is green and environment-friendly, so the method can be popularized and used in the fields of biomedicine, water purification and the like.
3. The method has the advantages of cheap and easily obtained raw materials, convenient transportation, mild reaction process, high efficiency, no secondary pollution in reaction, low toxicity and wide pH range. The method can play an important role in the field of environmental management.
Drawings
FIG. 1 is a singlet oxygen ESR spectrum measured in application test example 1.
FIG. 2 is a graph showing the effect of singlet oxygen generated by various metal oxides rich in hydroxyl groups on the degradation of bisphenol A in Experimental example 2.
Detailed Description
The present invention is further illustrated by, but is not limited to, the following specific examples.
The raw materials used in the following examples are all commercially available products and were analytically pure.
Example 1:
a method for activating hydrogen persulfate to generate singlet oxygen by using a hydroxyl-rich metal oxide comprises the following steps:
0.5g of magnesium oxide and 0.21g of potassium hydrogen persulfate composite salt are weighed and dispersed in 1L of water to obtain a mixed solution, the mixed solution is stirred and reacted for 1h at the temperature of 25 ℃, sampling and filtering are carried out, a TEMP probe ESR is used for detection, and singlet oxygen is generated in the reaction solution.
Example 2:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: sodium peroxodisulfate is used instead of oxone.
Example 3:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: magnesium hydroxide is used instead of magnesium oxide.
Example 4:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: calcium hydroxide was used instead of magnesium oxide.
Example 5:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: aluminum hydroxide was used instead of magnesium oxide.
Example 6:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: zinc hydroxide was used instead of magnesium oxide.
Example 7:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: ethanol-water was used instead of water.
Example 8:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: methanol-water was used instead of water.
Example 9:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: ether-water was used instead of water.
Example 10:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: tert-butanol-water was used instead of water.
Example 11:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: 0.40g of magnesium oxide and 0.10g of oxone complex salt were weighed out and dispersed in 1L of water.
Example 12:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: 0.60g of magnesium oxide and 0.15g of oxone complex salt were weighed out and dispersed in 1L of water.
Example 13:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: 0.80g of magnesium oxide and 0.26g of oxone complex salt were weighed out and dispersed in 1L of water.
Example 14:
the method for activating a persulfate to produce singlet oxygen with a metal oxide rich in hydroxyl groups as described in example 1, except that: 0.95g of magnesium oxide and 0.35g of oxone complex salt were weighed out and dispersed in 1L of water.
Application test example 1:
the reaction solutions of examples 1, 3, 4, 5 and 6 were filtered, and singlet oxygen in the filtered reaction solutions was detected with a TEMP probe ESR, and the detection results are shown in fig. 1.
Application test example 2:
preparing simulated wastewater of 10mg/L bisphenol A by taking bisphenol A as a model pollutant, respectively weighing 50mg of magnesium oxide, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, zinc hydroxide and 9.22mg of potassium hydrogen persulfate, dispersing in 50mL of the simulated wastewater, sampling 2mL of the wastewater every 10 minutes, filtering, quenching the sample with 0.5mL of ethanol, detecting the concentration of the bisphenol A in the sample by a liquid phase, reacting for 1h, and degrading as shown in figure 2.
An experimental instrument: high Performance Liquid Chromatography (HPLC), model ELITE P1201, instrument equipped with a diode array detector and a C18 reverse phase column (5 μm, 4.6mm 150mm), mobile phase methanol/water (70: 30, v/v), flow rate 1mL/min, column temperature 40 ℃, BPA detection wavelength 278 nm.