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WO2017201795A1 - 利用有机膜产生羟基自由基及去除水中有机污染物的方法 - Google Patents

利用有机膜产生羟基自由基及去除水中有机污染物的方法 Download PDF

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WO2017201795A1
WO2017201795A1 PCT/CN2016/087168 CN2016087168W WO2017201795A1 WO 2017201795 A1 WO2017201795 A1 WO 2017201795A1 CN 2016087168 W CN2016087168 W CN 2016087168W WO 2017201795 A1 WO2017201795 A1 WO 2017201795A1
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sheet material
hydroxyl radicals
hydroxyl radical
nitrocellulose
water
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French (fr)
Inventor
邰超
张少栋
赵同谦
宋党育
冯磊
毛宇翔
齐永安
张国成
张立军
王娟
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Henan University of Technology
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/30—Treatment of water, waste water, or sewage by irradiation
    • C02F1/32—Treatment of water, waste water, or sewage by irradiation with ultraviolet light
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/08—Polysaccharides
    • B01D71/12—Cellulose derivatives
    • B01D71/20—Esters of inorganic acids, e.g. cellulose nitrate
    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/06—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing polymers
    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/06—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing polymers
    • B01J31/061—Chiral polymers
    • 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
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
    • B01J35/58—Fabrics or filaments
    • B01J35/59—Membranes
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/725—Treatment of water, waste water, or sewage by oxidation by catalytic oxidation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/80—Type of catalytic reaction
    • B01D2255/802—Photocatalytic
    • 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
    • B01J2235/00—Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
    • 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
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/34—Organic compounds containing oxygen
    • 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
    • C02F2101/30—Organic compounds
    • C02F2101/34—Organic compounds containing oxygen
    • C02F2101/345—Phenols
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/44—Time
    • 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
    • C02F2305/02—Specific form of oxidant
    • C02F2305/023—Reactive oxygen species, singlet oxygen, OH radical
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/30—Wastewater or sewage treatment systems using renewable energies
    • Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy

Definitions

  • the application belongs to the field of photochemical technology and sewage treatment, and particularly relates to a method for generating hydroxyl radicals by using an organic film and removing organic pollutants in water.
  • Hydroxyl radical is a kind of active oxygen radical, which has strong oxidizing property and oxidation-reduction potential of 2.80V, which is second only to fluorine atom, and can diffusely control the rate with most inorganic or organic substances.
  • the reaction rate constant is generally greater than 10 8 mol L -1 s -1 .
  • hydroxyl radicals are used in the degradation of organic pollutants and are the most important active intermediates in advanced oxidation process wastewater treatment processes.
  • the chemical catalysis method generally adopts the Fenton reaction, and the hydrogen peroxide catalyzes the decomposition of hydrogen peroxide to generate hydroxyl radicals.
  • the method is simple and easy, and relatively inexpensive, but a large amount of iron-containing sludge is generated when applied on a large scale, which is unchanged for subsequent processing; Ozone and hydrogen peroxide photolyze under the action of ultraviolet light, which can generate hydroxyl radicals, but need to add hydroxyl radical precursor ozone and hydrogen peroxide, and have more side reactions; photocatalytic generation of hydroxyl radicals by using semiconductor titanium dioxide particles as catalyst It is necessary to ensure that the catalyst is in suspension, and photocatalysis also needs to separate the photocatalyst, and the continuous operability is poor, and the dissolved oxygen has a great influence on the photocatalytic generation of hydroxyl radicals by titanium dioxide; the method of electrocatalyzing the generation of hydroxyl radicals to dissolved oxygen in water The catalytic component has higher requirements and the current efficiency is lower; the ray method has the problems of high cost and great harm to the human body.
  • the present invention provides a method of producing a hydroxyl radical using an organic film, characterized in that the method comprises:
  • nitrocellulose sheet material as a photocatalytic material, irradiating the surface of the nitrocellulose sheet material with light having a wavelength of more than 280 nm to cause photochemical crystallization of the nitrocellulose sheet material
  • the reaction produces hydroxyl radicals.
  • the light source used is sunlight or a solar light having a wavelength greater than 280 nm.
  • the nitrocellulose sheet material is a nitrocellulose membrane.
  • the surface of the nitrocellulose sheet material is irradiated for a time of 60 minutes or more.
  • the method further comprises adjusting the rate of production of hydroxyl radicals by adjusting the surface area of the membrane and the intensity of the light.
  • the present invention provides a method for removing organic pollutants in water by using an organic film to generate hydroxyl radicals, characterized in that the method comprises:
  • nitrocellulose sheet material as a photocatalytic material with a wavelength greater than 280 nm Irradiating the surface of the nitrocellulose sheet material to cause photochemical reaction of the surface of the nitrocellulose sheet material to generate hydroxyl radicals;
  • the method is for removing phenol, bisphenol A and thiamphenicol in water.
  • the light source used is sunlight or a solar light having a wavelength greater than 280 nm.
  • the surface of the nitrocellulose sheet material is irradiated for a time of 60 minutes or more.
  • the method further comprises adjusting the rate of production of hydroxyl radicals by adjusting the surface area of the membrane and the intensity of the light.
  • the molecular structure of the nitrocellulose mentioned in the present invention is:
  • the method for generating hydroxyl radicals uses a nitrocellulose membrane as a photocatalytic material, and the nitrocellulose membrane is placed in water or an aqueous solution, and the sun or a solar light having a wavelength greater than 280 nm is used as a light source for illumination.
  • the nitrocellulose membrane is photochemically reacted to produce hydroxyl radicals.
  • the rate of hydroxyl radical generation can be achieved by adjusting the surface area and light intensity of the membrane.
  • the hydroxyl radicals generated can remove phenol, bisphenol A and Typical organic pollutants such as thiamphenicol.
  • Nitrocellulose is inexpensive and widely used in inks, leather, plastic products and other fields. Nitrocellulose is the main material of the microporous membrane, and the film forming process is very mature. The invention is issued It is now possible to produce hydroxyl radicals under the illumination of nitrocellulose, which is used as a photocatalytic material to generate hydroxyl radicals under the irradiation of light with a wavelength greater than 280 nm. It has a good removal effect on organic pollutants and is expected to be applied to water treatment. field.
  • the effect of UVB on the photocatalytic production of hydroxyl radicals on nitrocellulose membranes is extremely advantageous compared to other wavelengths, which is about eight times greater than the UVA effect. Therefore, it is preferred to use light-to-nitrocellulose in the UVB spectral range.
  • the film is irradiated.
  • the wavelength of the illumination source is selected to be 300-320 nm.
  • the nitrocellulose membrane is formed into a wavy shape having a sinusoidal surface. Applicants have found that the nitrocellulose membrane of this structure has a significantly higher light utilization rate than conventional flat nitrocellulose membranes and higher than other shapes of cellulose membranes.
  • the hydroxyl radical is generated on the surface of the nitrocellulose membrane, which is convenient for recycling and reuse, solves the problem that the recovery of the particulate catalyst is difficult, and the method of the invention can stably, continuously and uniformly generate hydroxyl radicals. , the controllable formation of hydroxyl radicals is achieved.
  • the process of the invention does not require the introduction of any hydroxyl radical precursors, avoiding secondary contamination.
  • the nitrocellulose membrane Due to the ultraviolet radiation in the ultraviolet region with a wavelength greater than 280 nm, the nitrocellulose membrane can generate hydroxyl radicals, which can directly use sunlight and reduce the cost of water treatment.
  • nitrocellulose membrane is used to overcome the mutual shading problem of the particulate catalyst, the rate of generation of hydroxyl radicals can be adjusted by adjusting the membrane area.
  • nitrocellulose is inexpensive and easy to be widely applied.
  • Figure 1 shows the ESR qualitative analysis of photocatalytic hydroxyl radical generation on the surface of nitrocellulose membrane. fruit
  • Figure 2 is a time-concentration curve of hydroxyl radicals under different membrane areas
  • Figure 3 is a time-concentration curve of hydrolysis of nitrocellulose membrane to nitrate and nitrite
  • Figure 4 is a comparison of the formation of hydroxyl radicals under illumination by nitrite, aqueous nitrate solution and nitrocellulose membrane;
  • Figure 5 shows the photocatalytic generation of hydroxyl radicals on the surface of nitrocellulose membrane under nitrogen, oxygen and control conditions
  • Figure 6 is a time-concentration curve of hydroxyl radical generation under different repetition times when the nitrocellulose membrane is reused
  • Figure 7 shows the effect of spectral interval (A), light intensity (B), pH (C) and temperature (D) on hydroxyl radical generation.
  • Figure 8 is a graph showing the relationship between the concentration of phenol, bisphenol A and thiamphenicol in the photocatalytic removal of phenol, bisphenol A and thiamphenicol in the nitrocellulose membrane under sunlight;
  • Figure 9 shows the relationship between the concentration of phenol, bisphenol A and thiamphenicol in the photocatalytic removal of phenol, bisphenol A and thiamphenicol in water under sunlight.
  • nitrocellulose membrane was cut into strips of 2 cm in length and 0.1 cm in width, inserted into a quartz sample tube, and inhaled 100 mM dimethyl pyridine N-oxide (DMPO) for in situ electron self-in- Rotational resonance spectrum analysis.
  • DMPO dimethyl pyridine N-oxide
  • the generation of hydroxyl radicals was monitored in real time with 180W solar light. The results are shown in Fig. 1.
  • the background signal is basically a flat line.
  • the characteristic signals of the hydroxyl radical and the DMPO adduct can be observed, and four peaks and peak height ratios appear.
  • the measurement of the hydroxyl radical was carried out by means of electron spin resonance (ESR) after DMPO capture.
  • ESR electron spin resonance
  • the electron spin resonance experimental device consists of ESR (Germany Bruker EMX-plus 10/12) spectrometer and solar light (Megra, USA).
  • the ESR experimental parameters are as follows: microwave frequency 9.8527 GHz; microwave power 20 mW; scanning range 3459-3559G ; scan step size 1G.
  • the amount of hydroxyl radical production is linear with the increase of the area of the nitrocellulose membrane, indicating that the nitrocellulose membrane can quantitatively and stably generate hydroxyl radicals.
  • the inventors conducted the same experiment on cellulose and cellulose acetate membranes. However, the formation of phenol was not observed in cellulose and cellulose acetate membrane under the same light conditions, indicating that the photocatalytic hydroxyl radical production of nitrocellulose membrane is closely related to the nitro group in nitrocellulose membrane.
  • the nitrocellulose membrane is chemically structurally a nitrate of cellulose, which may be hydrolyzed to produce nitrate or nitrite. It is currently not possible to exclude the latter from generating hydroxyl radicals under illumination.
  • a hydrolysis experiment of a nitrocellulose membrane was carried out. A ⁇ 47mm nitrocellulose membrane was placed in pure water and hydrolyzed at 35 ° C. The nitrate and nitrite produced by hydrolysis were determined by ion chromatography and compared with the blank and standard. The results are shown in the figure. 3 is shown.
  • the nitrocellulose membrane can only be slightly hydrolyzed in water; compared with the standard, after 2 hours of hydrolysis, only 0.8 ⁇ M of nitrite and 2.3 ⁇ M of nitrate are formed in the solution.
  • the formation of hydroxyl radicals under illumination of 0.8 ⁇ M nitrite and 2.3 ⁇ M nitrate solution under the same conditions was investigated and compared with the formation of hydroxyl radicals by nitrocellulose membrane. The results are shown in Fig. 4. It can be seen that the formation of hydroxyl radicals in the nitrocellulose membrane is mainly generated on the surface of the membrane, while the nitrate and nitrite produced by hydrolysis in the solution phase have substantially no effect.
  • Example 4 Photocatalytic generation of hydroxyl radicals on the surface of nitrocellulose membrane under nitrogen and oxygen
  • Fig. 7A shows that the effective spectral range of photocatalytic production of hydroxyl radicals by nitrocellulose membranes is UVA and UVB, and the ability of UVB to generate hydroxyl radicals is stronger than that of UVA.
  • the visible region is basically ineffective.
  • the method for measuring a hydroxyl radical is to react with benzene to form phenol to reflect the formation of a hydroxyl radical.
  • Phenol was determined by high performance liquid chromatography (Agilent 1200, USA).
  • the separation column was Zorbax SB-C18 (150 mm ⁇ 4.6 mm, 5 ⁇ m); the detector was a fluorescence detector with excitation and emission wavelengths of 260 and 310 nm, respectively;
  • the phase was 40% aqueous acetonitrile (v/v), the pH was adjusted to about 2 to 3 with hydrochloric acid, and the mobile phase flow rate was 1 ml/min.
  • Example 7 (Nitrogen lamp and sunlight nitrocellulose membrane catalyzed removal of organic pollutants in water)
  • the illumination time of the nitrocellulose membrane is greater than or equal to 60 minutes, and the Applicant has found that if the nitrocellulose membrane is continuously illuminated, the hydroxyl is after 60 minutes.
  • the rate of generation of radicals is about three times that of hydroxyl radicals in 60 minutes, and if the light is continued after the middle stops, the rate of generation of hydroxyl radicals returns to the normal rate.
  • the nitrocellulose membrane and sewage are preheated prior to illumination, and the rate of hydroxyl radical generation at 35 ° C is about twice that of 20 °C.
  • the larger the membrane area the faster the rate of generation of hydroxyl radicals. Therefore, in order to improve the treatment effect of the pollutants, the contact area between the membrane and the sewage should be increased as much as possible.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Inorganic Chemistry (AREA)
  • Catalysts (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Physical Water Treatments (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)

Abstract

一种利用有机膜产生羟基自由基的方法，该方法采用硝酸纤维素片状材料为光催化材料，将其置于水中，以太阳或者波长大于280nm的太阳灯为光源进行光照，使其发生表面光化学反应产生羟基自由基，羟基自由基的产生速率可以通过调节膜表面积和光强来实现。还公开了一种利用有机膜产生羟基自由基去除水中有机污染物的方法，该方法产生的羟基自由基可以很好的去除水中的苯酚、双酚A和甲砜霉素等典型的有机污染物。这种产生羟基自由基的方法简单、经济、高效，且不需要在水溶液中引入任何羟基自由基前驱体，羟基自由基产生在固相膜表面，不会带来二次污染，可应用于废水处理等领域。

Description

利用有机膜产生羟基自由基及去除水中有机污染物的方法
相关申请
本申请主张于2016年5月25日提交的、名称为“利用有机膜产生羟基自由基及去除水中有机污染物的方法”的中国发明专利申请:2016103538072的优先权。
技术领域
本申请属于光化学技术和污水处理领域，具体涉及一种利用有机膜产生羟基自由基及去除水中有机污染物的方法。
背景技术
羟基自由基(·OH)是活性氧自由基的一种，具有极强的氧化性，氧化还原电位2.80V，仅次于氟原子，能够与绝大多数的无机物或者有机物以扩散控制的速率进行反应，反应速率常数一般大于108mol L-1s-1。在环境科学领域，羟基自由基则被用于有机污染物的降解处理，是高级氧化过程废水处理工艺的最重要的活性中间体。
产生羟基自由基的方法较多，大致可以分为化学催化、臭氧/双氧水光解、光催化、电催化以及射线法等。化学催化法一般采用Fenton反应，用铁离子催化双氧水分解产生羟基自由基，该方法简单易行，较为廉价，但较大规模应用时会产生大量的含铁淤泥，为后续处理带来不变；臭氧和双氧水在紫外光的作用下发生光解，可产生羟基自由基，但需要加入羟基自由基前驱体臭氧和双氧水，副反应较多；采用半导体二氧化钛颗粒等作为催化剂光催化产生羟基自由基，需保证催化剂处于悬浮状态，而且光催化同时还需要分离光催化剂，连续操作性差，并且溶解氧对二氧化钛光催化产生羟基自由基具有较大影响；电催化产生羟基自由基的方法对水中的溶解氧以及其催化成分要求较高，并且电流效率较低；射线法则存在成本较高、对人体危害较大的问题。
因此，目前所通常采用的羟基自由基的几种产生方法要么具有较多副反应，要么操作性差效率低下，要么对环境或人体具有较大危害，所以，现有的产生羟基自由基的方法均存在其各自的问题，难以推广应用。
发明内容
鉴于前述提到的现有技术所存在的缺陷，本发明的目的是提供一种新的产生羟基自由基的方法以及利用所产生的羟基自由基进行有机污染物处理的方法。本发明希望该方法具有可调控、成本低、工艺简单、易于操作、不会带来二次污染等优点，可以很好的去除水中的苯酚、双酚A和甲砜霉素等典型的有机污染物。
具体而言，本发明提供了一种利用有机膜产生羟基自由基的方法，其特征是，所述方法包括：
1)、制备硝酸纤维素片状材料；
2)、将所述硝酸纤维素片状材料置于水溶液中；
3)、以所述硝酸纤维素片状材料为光催化材料，通过波长大于280nm的光对所述硝酸纤维素片状材料的表面进行照射，使所述硝酸纤维素片状材料发生膜表面光化学反应产生羟基自由基。
优选地，在对所述硝酸纤维素片状材料进行照射时，所用的光源为太阳光或者波长大于280nm的太阳灯。
优选地，所述硝酸纤维素片状材料为硝酸纤维素膜。
优选地，对所述硝酸纤维素片状材料的表面进行照射的时间大于等于60分钟。
优选地，所述方法还包括通过调节膜表面积和光强来调节羟基自由基的产生速率。
另一方面，本发明提供一种利用有机膜产生羟基自由基去除水中有机污染物的方法，其特征在于，所述方法包括：
1)、制备硝酸纤维素片状材料；
2)、将所述硝酸纤维素片状材料置于含水和有机污染物的液体中；
3)、以所述硝酸纤维素片状材料为光催化材料，通过波长大于280nm 的光对所述硝酸纤维素片状材料的表面进行照射，使所述硝酸纤维素片状材料发生膜表面光化学反应产生羟基自由基；
4)、利用所产生的羟基自由基对液体中的有机污染物进行氧化分解。
优选地，所述方法用于去除水中的苯酚、双酚A和甲砜霉素。
优选地，在对所述硝酸纤维素片状材料进行照射时，所用的光源为太阳光或者波长大于280nm的太阳灯。
优选地，对所述硝酸纤维素片状材料的表面进行照射的时间大于等于60分钟。
优选地，所述方法还包括通过调节膜表面积和光强来调节羟基自由基的产生速率。
本发明中所提到的硝酸纤维素的分子结构式为：
Figure PCTCN2016087168-appb-000001
综上，本发明提供的产生羟基自由基的方法是采用硝酸纤维素膜为光催化材料，将硝酸纤维素膜置于水或水溶液中，以太阳或者波长大于280nm的太阳灯为光源进行光照，使硝酸纤维素膜发生膜表面光化学反应产生羟基自由基，羟基自由基的产生速率可以通过调节膜表面积和光强来实现，产生的羟基自由基可以很好的去除水中的苯酚、双酚A和甲砜霉素等典型的有机污染物。
硝酸纤维素价廉物美，广泛应用于油墨、皮革、塑料制品等领域。硝酸纤维素是微孔滤膜的主要材料，成膜工艺十分成熟。本发明则是发 现了硝酸纤维素光照下可以产生羟基自由基，将之作为光催化材料，在波长大于280nm的光辐射下，产生羟基自由基，对有机污染物具有很好的去除作用，有望应用到水处理领域。
申请人发现，利用UVB对硝酸纤维素膜光催化产生羟基自由基的效果与其他波长相比优势极其明显，约为UVA作用的8倍，因此，优选地，利用UVB光谱区间的光对硝酸纤维素膜进行照射。优选地，照明光源的波长选为300-320nm。
在另一种优选实现方式中，硝酸纤维素膜制成表面呈正弦波形状的波浪状。申请人发现，这种结构的硝酸纤维素膜的光照利用率明显高于普通的平整的硝酸纤维素膜也高于其他形状的纤维素膜。
本发明的有益效果是：
1.在本发明的方法中，羟基自由基产生在硝酸纤维素膜表面，便于回收再利用，解决了颗粒催化剂的回收难的问题，并且本发明的方法可以稳定、连续和匀速产生羟基自由基，实现了羟基自由基的可控生成。
2.本发明的方法不需要引入任何羟基自由基前驱体，避免了二次污染。
3.由于波长大于280nm的紫外区光辐射可使硝酸纤维素膜产生羟基自由基，可以直接利用太阳光，降低了水处理成本。
4.由于采用硝酸纤维素膜，克服了颗粒催化剂的相互遮光问题，可以通过调节膜面积的方法调节羟基自由基的产生速率。
5.与目前所采用的二氧化钛催化剂相比，硝酸纤维素价格低廉，易于大规模推广应用。
附图说明
图1为硝酸纤维素膜表面光催化产生羟基自由基的ESR定性分析结 果；
图2为不同膜面积下羟基自由基的时间-浓度曲线；
图3为硝酸纤维素膜水解生成硝酸根和亚硝酸根的时间-浓度曲线；
图4为亚硝酸根、硝酸根水溶液和硝酸纤维素膜光照下羟基自由基生成的对比结果；
图5为通氮、通氧以及对照实验条件下硝酸纤维素膜表面光催化产生羟基自由基情况；
图6为硝酸纤维素膜重复利用时，不同重复次数情况下羟基自由基产生的时间-浓度曲线；
图7为光谱区间(A)、光强(B)、pH(C)和温度(D)对羟基自由基产生的影响
图8为太阳灯下硝酸纤维素膜光催化去除水中苯酚、双酚A和甲砜霉素时，三者浓度随时间的变化关系；
图9为太阳光下硝酸纤维素膜光催化去除水中苯酚、双酚A和甲砜霉素时，三者浓度随时间的变化关系。
具体实施方式
下述实施例是对于发明内容的进一步说明以作为对本发明技术内容的阐释，但本发明的实质内容并不限于下述实施例所述，本领域的普通技术人员可以且应当知晓任何基于本发明实质精神的简单变化或替换均应属于本发明所要求的保护范围。
实施例1
在本实施例中，进行硝酸纤维素膜表面光催化产生羟基自由基的ESR定性分析。
将硝酸纤维素膜切割为长2cm、宽0.1cm的条状，塞入石英样品管，吸入100mM的甲基吡啶N-氧化物(dimethyl pyridine N-oxide，简称 DMPO)后，进行原位电子自旋共振谱分析检测。在180W太阳灯光照的情况下，实时监测羟基自由基的生成情况。结果如图1所示，在未光照时，背景信号基本为一平线，光照4min、8min和16min时，能够观察到羟基自由基与DMPO加合物的特征信号，出现4个峰，峰高比值为1：2：2：1，超精细分裂常数aH＝aN＝14.9高斯，随光照时间增加，峰高线性增加，确认硝酸纤维素膜表面光催化可以产生羟基自由基，羟基自由基产生量与光照时间呈线性增加关系。
在本实施例中羟基自由基的测定采用DMPO捕获后、通过电子自旋共振(electron spin resonance,ESR)的方法进行测定。电子自旋共振实验装置由ESR(德国Bruker EMX-plus 10/12)波谱仪和太阳灯(美国Megra，180W)组成，ESR实验参数如下：微波频率9.8527GHz；微波功率20mW；扫描范围3459～3559G；扫描步长1G。
实施例2(不同膜面积下羟基自由基的生成情况)
在100mL烧杯中，加入50mL 10mM苯溶液，放入直径为47mm(φ47mm)的整张、二分之一张、四分之一张和八分之一张的硝酸纤维素膜片，并使膜片静止在烧杯底，置于180W太阳灯下照射，硝酸纤维素膜光照形成的羟基自由基与苯反应生成苯酚。每隔20min取样，通过高效液相色谱分析溶液中苯酚浓度的变化情况，反映羟基自由基的生成情况。结果如图2所示，可以看出，羟基自由基的产生量随硝酸纤维素膜面积增加基本呈线性关系，表明硝酸纤维素膜光照可以定量稳定的产生羟基自由基。为了更加明确自由基的产生原因，发明人对纤维素和乙酸纤维素膜进行了同样的实验。而纤维素和乙酸纤维素膜在同样的光照条件下则没有发现苯酚的生成，说明硝酸纤维素膜光催化羟基自由基的产生与硝酸纤维素膜中的硝基具有密切关系。
实施例3(溶液相硝酸根和亚硝酸根光照产生羟基自由基的排除)
硝酸纤维素膜从化学结构上讲是纤维素的硝酸酯，可能发生水解产生硝酸根或亚硝酸根，目前不能排除后两者在光照下也可以产生羟基自由基。为排除上述可能，进行了硝酸纤维素膜的水解实验。将一张φ47mm的硝酸纤维素膜置于纯水中，于35℃下进行水解，采用离子色谱对水解产生的硝酸根和亚硝酸根进行测定，并与空白和标准进行比对，结果如图3所示。可以看出，硝酸纤维素膜在水中只能发生轻微水解；与标准进行比对，经过2小时的水解，溶液中只有0.8μM的亚硝酸根和2.3μM的硝酸根生成。考察了相同条件下0.8μM的亚硝酸根和2.3μM的硝酸根水溶液光照下羟基自由基的生成情况，并与硝酸纤维素膜光照羟基自由基生成进行对比，结果如图4所示。可以看出，硝酸纤维素膜光照羟基自由基的生成主要产生于膜表面，而溶液相中水解产生的硝酸根和亚硝酸根基本不起作用。
实施例4(通氮通氧情况下硝酸纤维素膜表面光催化产生羟基自由基)
用事先通氮、通氧30min的超纯水分别在通氮和通氧的情况下配置10mM苯溶液，分别在100mL烧杯中，加入50mL上述苯溶液，放入φ47mm的硝酸纤维素膜片一张，并使膜片静止在烧杯底，分别在通氮、通氧的条件下置于180W太阳灯下照射，硝酸纤维素膜光照形成的羟基自由基与苯反应生成苯酚。每隔20min取样，通过高效液相色谱分析溶液中苯酚浓度的变化情况，反映羟基自由基的生成情况，并与不通气条件下的羟基自由基生成情况进行比较。结果如图5所示，可以看出，通氮和通氧对硝酸纤维素膜光催化产生羟基自由基没有影响，说明羟基自由基是由硝酸纤维素膜表面直接产生，与溶液中的氧没有关系，硝酸纤维素膜产生羟基自由基不需要任何前驱体。
实施例5(硝酸纤维素膜重复利用情况下产生羟基自由基)
在100mL烧杯中，加入50mL 10mM苯溶液，放入φ47mm的硝酸纤维素膜片一张，并使膜片静止在烧杯底，置于180W太阳灯下照射，硝酸纤维素膜光照形成的羟基自由基与苯反应生成苯酚。每隔20min取样，通过高效液相色谱分析溶液中苯酚浓度的变化情况。每两小时将烧杯中的苯溶液更换为未经光照的新鲜10mM苯溶液，并充分洗涤硝酸纤维素膜和烧杯。重复上次步骤，以考察硝酸纤维素重复光照产生羟基自由基的活性是否下降。结果如图6所示，可以看出即使经过20次的重复使用，硝酸纤维素膜光照产生羟基自由基的活性仍未有明显下降。
实施例6
如图7所示，在灯高度：12cm；温度：35℃；pH 7的条件下，采用不同的滤光膜分别过滤太阳灯光中的UVA(320～400nm)、UVB(280～400nm)，考察了不同光谱区间对羟基自由基生成的影响(图7A)，可以看出，硝酸纤维素膜光催化产生羟基自由基的有效光谱区间为UVA和UVB，UVB产生羟基自由基的能力要强于UVA，而可见光区则基本不起作用。
在光谱为：UVA+UVB+Vis；温度：35℃；pH 7的条件下，通过调节太阳灯的照射高度调节光强，考察了照射高度分别在12、14、16和18cm条件下光强(光通量分别为1730、1450、1113和886μmol m-2s-1)对羟基自由基生成的影响(图7B)，可以看出，硝酸纤维素膜光催化产生羟基自由基随光强的增加而增加。
在光谱为：UVA+UVB+Vis；灯高度：12cm；温度35℃的条件下，用0.1M磷酸和0.1M NaOH调节酸度考察了不同酸度条件下对羟基自由基生成的影响(图7C)，可以看出在pH 4～8的范围内，酸度对硝酸纤维素膜光催化产生羟基自由基影响很小。
在光谱为：UVA+UVB+Vis；灯高度：12cm；pH 7的情况下，考 察了不同温度对羟基自由基生成的影响(图7D)，可以看出，温度越高，越有利于硝酸纤维素膜光催化产生羟基自由基。综上所述，硝酸纤维素膜光催化产生羟基自由基起主要作用的光谱区间是UVB；在pH 4～8的范围内酸度对羟基自由基产生影响较小；温度越高，光强越强，越有利于羟基自由基的产生。
实施例2～6中，羟基自由基的测定方法是利用羟基自由基与苯反应生成苯酚，以反映羟基自由基的生成情况。苯酚采用高效液相色谱(美国安捷伦1200)进行测定，所用分离柱为Zorbax SB-C18(150mm×4.6mm,5μm)；检测器为荧光检测器，激发波长和发射波长分别为260和310nm；流动相为40％乙腈水溶液(v/v)，用盐酸调节pH为2～3左右，流动相流速为1ml/min。
实施例7(太阳灯和太阳光下硝酸纤维素膜催化对水中有机污染物的去除)
在100mL烧杯中，分别加入50mL 50μM的苯酚、双酚A和甲砜霉素水溶液，放入φ47mm的硝酸纤维素膜片一张，并使膜片静止在烧杯底，置于180W太阳灯下照射。每隔20min取样，通过高效液相色谱分析溶液中苯酚、双酚A和甲砜霉素浓度的变化情况；在同样的实验条件下，在太阳光下进行相同的实验，结果分别如图8和图9所示，可以看出，无论是在太阳灯下或者太阳光下，硝酸纤维素膜光照均可很好的去除苯酚、双酚A和甲砜霉素。但在没有光照或者光照下溶液中有羟基自由基清除剂异丙醇(10mM)存在的情况下，均未发现苯酚、双酚A和甲砜霉素有任何的去除。以上结果说明，硝酸纤维素膜光催化去除水中的有机污染物的活性物种为羟基自由基。
在一种优选实现方式中，对硝酸纤维素膜的光照时间大于等于60分钟，申请人发现，若对硝酸纤维素膜进行持续光照，则在60分钟之后羟 基自由基的产生速率约为60分钟内羟基自由基产生速率的3倍，而如果中间停止后再继续光照，则羟基自由基的产生速率又恢复到正常速率。
在另一种优选实现方式中，在进行光照之前，对硝酸纤维素膜和污水进行预热，35℃时羟基自由基的产生速率约为20℃的2倍。
在第三种优选方式中，膜面积越大，羟基自由基产生速率越快，因此要得到提高污染物处理效果，应尽可能的提高膜与污水的接触面积。
虽然上面结合本发明的优选实施例对本发明的原理进行了详细的描述，本领域技术人员应该理解，上述实施例仅仅是对本发明的示意性实现方式的解释，并非对本发明包含范围的限定。实施例中的细节并不构成对本发明范围的限制，在不背离本发明的精神和范围的情况下，任何基于本发明技术方案的等效变换、简单替换等显而易见的改变，均落在本发明保护范围之内。

Claims (10)

  1. 一种利用有机膜产生羟基自由基的方法，其特征是，所述方法包括：
    1)、制备硝酸纤维素片状材料；
    2)、将所述硝酸纤维素片状材料置于水溶液中；
    3)、以所述硝酸纤维素片状材料为光催化材料，通过波长大于280nm的光对所述硝酸纤维素片状材料的表面进行照射，使所述硝酸纤维素片状材料发生膜表面光化学反应产生羟基自由基。
  2. 根据权利要求1所述的利用有机膜产生羟基自由基的方法，其特征在于，在对所述硝酸纤维素片状材料进行照射时，所用的光源为太阳光或者波长大于280nm的太阳灯。
  3. 根据权利要求1所述的利用有机膜产生羟基自由基的方法，其特征在于，所述硝酸纤维素片状材料为硝酸纤维素膜。
  4. 根据权利要求1所述的利用有机膜产生羟基自由基的方法，其特征在于，对所述硝酸纤维素片状材料的表面进行照射的时间大于等于60分钟。
  5. 根据权利要求1所述的利用有机膜产生羟基自由基的方法，其特征在于，所述方法还包括通过调节膜表面积和光强来调节羟基自由基的产生速率。
  6. 一种利用有机膜产生羟基自由基去除水中有机污染物的方法，其特征在于，所述方法包括：
    1)、制备硝酸纤维素片状材料；
    2)、将所述硝酸纤维素片状材料置于含水和有机污染物的液体中；
    3)、以所述硝酸纤维素片状材料为光催化材料，通过波长大于280nm 的光对所述硝酸纤维素片状材料的表面进行照射，使所述硝酸纤维素片状材料发生膜表面光化学反应产生羟基自由基；
    4)、利用所产生的羟基自由基对液体中的有机污染物进行氧化分解。
  7. 根据权利要求6所述的利用有机膜产生羟基自由基去除水中有机污染物的方法，其特征在于，所述方法用于去除水中的苯酚、双酚A和甲砜霉素。
  8. 根据权利要求6所述的利用有机膜产生羟基自由基去除水中有机污染物的方法，其特征在于，在对所述硝酸纤维素片状材料进行照射时，所用的光源为太阳光或者波长大于280nm的太阳灯。
  9. 根据权利要求6所述的利用有机膜产生羟基自由基去除水中有机污染物的方法，其特征在于，对所述硝酸纤维素片状材料的表面进行照射的时间大于等于60分钟。
  10. 根据权利要求6所述的利用有机膜产生羟基自由基去除水中有机污染物的方法，其特征在于，所述方法还包括通过调节膜表面积和光强来调节羟基自由基的产生速率。
PCT/CN2016/087168 2016-05-25 2016-06-25 利用有机膜产生羟基自由基及去除水中有机污染物的方法 Ceased WO2017201795A1 (zh)

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