CN109794291B - Bionic construction method and application of Ti @ BiOI-pDA @ CA self-cleaning film - Google Patents
Bionic construction method and application of Ti @ BiOI-pDA @ CA self-cleaning film Download PDFInfo
- Publication number
- CN109794291B CN109794291B CN201910016781.6A CN201910016781A CN109794291B CN 109794291 B CN109794291 B CN 109794291B CN 201910016781 A CN201910016781 A CN 201910016781A CN 109794291 B CN109794291 B CN 109794291B
- Authority
- CN
- China
- Prior art keywords
- pda
- bioi
- self
- membrane
- construction method
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Catalysts (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention belongs to the technical field of preparation of environment functional materials, and particularly relates to a bionic construction method and application of a Ti @ BiOI-pDA @ CA self-cleaning film. The self-cleaning film Ti @ BiOI-pDA @ CA is prepared by a phase inversion method by using polydopamine modified CA powder (pDA @ CA) as a film matrix and Ti @ BiOI as a photocatalyst, and is used for removing BPA in a solution. The membrane material obtained by the invention improves the compatibility of the Ti @ BiOI photocatalyst and the pDA @ CA membrane, further improves the photocatalytic performance, the anti-pollution performance and the antibacterial capacity of the self-cleaning membrane, and simultaneously effectively slows down the membrane pollution of the composite membrane with the photocatalytic function prepared by coupling the photocatalytic technology and the membrane separation technology, is convenient for continuous operation, is easy to recover, is superior to the powder catalyst, and promotes the practical application of the composite membrane.
Description
Technical Field
The invention belongs to the technical field of preparation of environment functional materials, and particularly relates to a bionic construction method and application of a Ti @ BiOI/pDA @ CA self-cleaning film.
Background
The phenol-containing wastewater is industrial wastewater with wide pollution range, large water quantity and serious harm, mainly comes from petrochemical industry, coal chemical industry, phenol production and phenolic resin production plants, coking plants, pharmaceutical plants and the like, and is one of the harmful wastewater which needs to be mainly treated in China. The discharge of a large amount of phenol-containing waste water aggravates the deterioration of the ecological environment, and hormone functions and physiological systems in human or animals ingested the phenolic compounds in the environment and food are disordered, so that even under the condition of low content of the phenolic compounds, the synthesis, release, effects and the like of hormones in organisms are affected, further the reproduction, development and behavior of the organisms are abnormal, and serious diseases can cause cancer, teratogenesis and mutation, thus threatening the health and survival of human beings. At present, there are various methods for treating the phenol-containing wastewater, and the photocatalytic technology has been recognized as one of the most promising green environmental purification technologies. However, among the known photocatalysts, the most efficient of the photocatalysts are generally nanoparticles, and the separation and recovery of the reaction solution thereof is a major technical obstacle to the promotion of commercial application thereof.
In recent years, the composite membrane with the photocatalytic function, which is prepared by coupling the photocatalytic technology and the membrane separation technology, can efficiently remove pollutants, and is green and environment-friendly. The two technologies are coupled, so that the membrane pollution is effectively slowed down, and the separation membrane serving as a support can effectively solve the problems of low utilization rate and difficulty in recycling of photocatalyst light, thereby further promoting the practical application of the photocatalyst. However, the conventional coupling method of the photocatalytic film has obvious disadvantages, such as poor compatibility of most catalysts with film materials during the co-mixing film preparation process, for example, Cellulose Acetate (CA) film lacks active functional groups on the polymer, and weak chemical interaction (such as hydrogen bond, van der waals and electrostatic interaction) between inorganic phase and polymer matrix may affect the adhesion of the nano-composite, so that the photocatalyst is easy to agglomerate, and the photocatalytic performance is affected.
Disclosure of Invention
The invention aims to prepare a Ti @ BiOI-pDA @ CA self-cleaning film by using cellulose acetate, DA and Ti @ BiOI, and apply the film to the efficient removal of trace pollutants bisphenol A (BPA). This patent is first through Dopamine (DA) modified CA powder, and the pyrocatechol group in DA can be through the metal that combines of chelation, has guaranteed Ti @ BiOI-pDA nano-material's structural stability to Ti @ BiOI nano-material's leaching has been inhibited. Importantly, pDA has good ultraviolet and visible light adsorption capacity and good photoconductivity under the irradiation of visible light, effectively avoids electron hole recombination of a semiconductor catalyst, and improves the photocatalytic activity.
A bionic construction method of a Ti @ BiOI-pDA @ CA self-cleaning film comprises the following steps:
(1) preparation of the composite photocatalyst (Ti @ BiOI):
weighing bismuth nitrate pentahydrate (Bi (NO)3)3·5H2O) is dispersed in ethanol and is subjected to ultrasonic treatment to obtain Bi (NO)3)3·5H2O dispersion liquid;
weighing KI, dissolving in deionized water, and slowly dripping the KI solution into Bi (NO)3)3·5H2Adding the O dispersion liquid into the O dispersion liquid, violently stirring for a period of time, then dropping titanium tetraisopropoxide into the O dispersion liquid, stirring, placing the O dispersion liquid into a reaction kettle for hydrothermal reaction, cooling, washing, centrifugally separating and drying after the reaction is finished to finally obtain the composite photocatalyst, and marking the composite photocatalyst as Ti @ BiOI;
(2) preparation of pDA @ CA composite:
weighing Tris-HCl, dissolving in deionized water, adjusting the pH value of the solution, sequentially adding CA powder, ethanol and dopamine DA into the Tris-HCl solution to obtain polydopamine pDA modified CA powder, and performing vacuum drying to obtain pDA @ CA;
(3) the bionic preparation method of the Ti @ BiOI-pDA @ CA self-cleaning film comprises the following steps:
sequentially adding the Ti @ BiOI catalyst prepared in the step (1) and the pDA @ CA powder prepared in the step (2) into dimethyl sulfoxide (DMSO), mechanically stirring uniformly to obtain a membrane casting solution, and scraping a membrane to obtain a blended membrane Ti @ BiOI-pDA @ CA.
In step (1), Bi (NO)3)3·5H2The molar concentration ratio of O to KI is 1: 1;
in the step (1), the stirring is magnetic stirring for 0.5-1.5 h;
in the step (1), the temperature of the hydrothermal reaction is 170-190 ℃, and the reaction time is 1.0-3.0 h.
In the step (2), the concentration of a Tris-HCl solution is 0.605mg/mL, the pH value is 8.5, the mass ratio of Tris-HCl, CA and DA is 0.605:20:1, the volume ratio of deionized water to ethanol is 30:1, the modification time is 4.0-8.0 h, the vacuum drying temperature is 40-60 ℃, and the drying time is 12-24 h;
in the step (3), the mass ratio of the total mass of the Ti @ BiOI catalyst and the pDA @ CA powder to the DMSO is 13:87, wherein the mass ratio of the Ti @ BiOI catalyst to the pDA @ CA powder is 2:11, and the mechanical stirring time is 6.0-10 hours.
The preparation process of the BiOI is the same as that in the step (1) except that titanium tetraisopropoxide is not dripped;
the preparation method of the BiOI-CA is different from the preparation method, in that titanium tetraisopropoxide is not added in the step (1), and dopamine DA is not added in the step (2);
the preparation method of Ti @ BiOI-CA is different from the preparation method, namely, dopamine DA is not added in the step (2);
the preparation method of BiOI-pDA @ CA is different from the preparation method, in that titanium tetraisopropoxide is not added in the step (1);
in the ethanol described in the above embodiment, CA powder can be sufficiently dispersed in a Tris-HCl solution at pH 8.5.
The Ti @ BiOI-pDA @ CA biomimetic composite catalytic membrane prepared by the invention is used for efficiently removing the pollutant BPA.
The invention has the beneficial effects that:
(1) proper amount of Ti is doped, and a Tidxy bond can be integrated into a local conduction band of the BiOI, so that the recombination of electron hole pairs is effectively inhibited, the photocatalytic performance is effectively improved, and the degradation rate of a target substance is improved.
(2) The DA is used for modifying the CA powder, and the catechol group in the DA can be combined with metal through chelation, so that the structural stability of the Ti @ BiOI-pDA nano material is ensured, and the leaching of the Ti @ BiOI nano material is inhibited. The membrane prepared by the method solves the problem of poor compatibility of the catalyst and the membrane matrix in the traditional blending catalysis membrane. And the pDA has good ultraviolet and visible light adsorption capacity and good photoconductivity under the irradiation of visible light, thereby effectively avoiding the electron hole recombination of a semiconductor catalyst and further improving the photocatalytic activity.
(3) The photocatalysis technology is combined with the membrane separation technology, so that the problem of difficult separation and recovery of the powder catalyst can be solved, and the problem of membrane pollution can be reduced.
Drawings
FIGS. 1(a) and (b) are transmission electron micrographs of the prepared BiOI and Ti @ BiOI, respectively.
FIG. 2 is a photocatalytic BPA removal experiment of various self-cleaning films and the Ti @ BiOI-pDA @ CA self-cleaning film prepared by the invention.
FIG. 3 shows the antibacterial performance test of various self-cleaning films and the Ti @ BiOI-pDA @ CA self-cleaning film prepared by the present invention.
FIG. 4 shows the anti-fouling performance test of various self-cleaning films and the Ti @ BiOI-pDA @ CA self-cleaning film prepared by the invention.
Detailed Description
The invention is further described with reference to the following description and specific examples.
The total mass of the casting solution is 10 g.
Example 1 preparation of Ti @ BiOI-pDA @ CA biomimetic composite catalytic membrane
(1) preparation of pDA @ CA composite material
Firstly, 0.1815g of Tris-HCl was dissolved in 300mL of deionized water, and the pH of the solution was adjusted to 8.5 to prepare a buffer solution; then 6.0g of CA powder, 10mL of absolute ethyl alcohol and 0.3g of DA are placed in the solution, stirred for 6.0h at room temperature, filtered, washed by deionized water, and dried in vacuum at 40 ℃ to constant weight to obtain dopamine modified CA powder.
(2) Preparation of Ti @ BiOI-pDA @ CA biomimetic composite catalytic membrane
Firstly, 200mg of Ti @ BiOI catalyst and 1.1g of pDA @ CA are weighed and dissolved in 8.7g of DMSO, then the mechanical stirring is carried out for 8.0h under the condition of 50 ℃ until the materials are uniformly dissolved to obtain a casting film liquid, the heat preservation and the standing are carried out for 4.0h under the condition of 50 ℃, bubbles generated by stirring are removed, the casting film liquid is flatly paved on a glass plate, a film with the thickness of 2.0mm is scraped out by a glass rod, the film is slowly immersed into deionized water after 30s, the film is taken out after being immersed for 30min, and the Ti @ BiOI-pDA @ CA bionic composite catalytic film is obtained and stored in the deionized water for later use.
(3) BPA removal experiment of Ti @ BiOI-pDA @ CA biomimetic composite catalytic membrane under illumination condition
a. Preparing a bisphenol A (BPA) solution with the concentration of 5.0mg/L, and placing the prepared solution in a dark place;
b. placing a prepared Ti @ BiOI-pDA @ CA bionic composite catalytic membrane in a photocatalytic reactor, adding 50mL of target degradation liquid prepared in the step a, turning on a circulating water source and a light source, and performing a removal experiment under an illumination condition;
c. sucking reaction liquid in a reactor of 3-5ml every 30min, centrifuging and measuring the ultraviolet-visible absorbance;
(4) escherichia coli strain K12 was put into a conical flask prepared with a nutrient broth and cultured with shaking at 37 ℃ for 16 hours. After the completion of the culture, the culture medium was washed with physiological saline under aseptic conditions to remove the nutrient solution, and then diluted to the original concentration. And then, under the aseptic condition, sucking 8mL of sterilized reactor containing 72mL of normal saline, placing the reactor in a xenon lamp catalytic device, and stirring for 10-20 min to uniformly disperse the Escherichia coli thalli in the normal saline.
Accurately weighing 0.2g of the prepared photocatalytic film, putting the photocatalytic film into the beaker, stirring for 10-20 min, reacting for 1h under the dark reaction condition, starting a xenon lamp for illumination, and diluting 10mL of mixed solution at intervals of 1h by 0.1mL6After doubling, 0.1mL of the dilution was pipetted and applied to the petri dish. After the experiment is finished, the culture dish is put in a constant temperature incubator at 37 ℃ for culturing for 16h, then the colony number of the escherichia coli is counted, and the data is recorded (the blank in figure 3 is the number of the escherichia coli without the photocatalytic film added).
(5) Anti-fouling experiment of Ti @ BiOI-pDA @ CA bionic composite catalytic membrane
First, a series of BSA curves with different concentrations are prepared, and the absorbance at 280nm is measured by an ultraviolet-visible spectrophotometer to draw a standard curve. Immersing a piece of membrane in 10mL of 1.0mg/mL BSA solution, standing for adsorption for 24h, measuring the absorbance of the solution, and calculating the adsorption concentration Qe (mg/cm) of BSA according to the formula (1)2)：
Wherein C is0And Ce is the initial and equilibrium concentration of BSA, V (mL) is the volume of BSA solution，S(cm2) Is the adsorption area of the membrane. The average of at least three measurements was determined.
Example 2 with the other conditions maintained, a comparative experiment was set up as follows: in the step (2), 200mg of BiOI catalyst is weighed and added into the membrane casting solution.
Example 3 with the other conditions being maintained, a comparative experiment was set up as follows: in step (2), 1.1g of unmodified CA is weighed and added to the membrane casting solution.
Example 4 with the other conditions ensured, a comparative experiment was set up as follows: 200mg of BiOI catalyst and 1.1g of unmodified CA powder were weighed into the membrane casting solution.
From fig. 1(a), it can be seen that the bisi has a flower-like structure, and from fig. 1(b), it can be seen that Ti is uniformly dispersed on the surface of the flower-like bisi.
FIG. 2 shows the experiment of removing BPA by photocatalysis of various self-cleaning films and the Ti @ BiOI-pDA @ CA self-cleaning film prepared by the invention, and the Ti @ BiOI-pDA @ CA self-cleaning film has excellent photocatalytic activity, and the removal rate of BPA solution of the film reaches 98% after the film is subjected to catalytic reaction for 60 min.
FIG. 3 shows the antibacterial property test of various self-cleaning films and the Ti @ BiOI-pDA @ CA self-cleaning film prepared by the present invention, and it can be seen from FIG. 3 that the Ti @ BiOI-pDA @ CA self-cleaning film has the best antibacterial property.
FIG. 4 is a test of the anti-fouling performance of various self-cleaning films and the Ti @ BiOI-pDA @ CA self-cleaning film prepared by the invention, and it can be seen from FIG. 4 that the absorbance of the prepared film is not obviously changed after the film statically adsorbs BSA24h, which indicates that the anti-fouling performance of the prepared anti-fouling self-cleaning film is good.
Claims (7)
1. A bionic construction method of a Ti @ BiOI-pDA @ CA self-cleaning film is characterized by comprising the following steps:
(1) preparation of the composite photocatalyst (Ti @ BiOI):
weighing bismuth nitrate pentahydrate, dispersing in ethanol, and performing ultrasonic treatment to obtain Bi (NO)3)3·5H2O dispersion liquid; weighing KI, dissolving in deionized water, and slowly dripping the KI solution into Bi (NO)3)3·5H2Adding the O dispersion liquid into the O dispersion liquid, violently stirring for a period of time, then dropping titanium tetraisopropoxide into the O dispersion liquid, stirring, placing the O dispersion liquid into a reaction kettle for hydrothermal reaction, cooling, washing, centrifugally separating and drying after the reaction is finished to finally obtain the composite photocatalyst, and marking the composite photocatalyst as Ti @ BiOI;
(2) preparation of pDA @ CA composite:
weighing Tris-HCl, dissolving in deionized water, adjusting the pH value of the solution, sequentially adding CA powder, ethanol and dopamine into the Tris-HCl solution to obtain polydopamine pDA modified CA powder, and performing vacuum drying to obtain pDA @ CA;
(3) the bionic preparation method of the Ti @ BiOI-pDA @ CA self-cleaning film comprises the following steps:
sequentially adding the Ti @ BiOI catalyst prepared in the step (1) and the pDA @ CA powder prepared in the step (2) into dimethyl sulfoxide (DMSO), mechanically stirring uniformly to obtain a membrane casting solution, and scraping a membrane to obtain a blended membrane Ti @ BiOI-pDA @ CA.
2. The biomimetic construction method of a Ti @ BiOI-pDA @ CA self-cleaning membrane as claimed in claim 1, wherein in step (1), Bi (NO) is used3)3·5H2The molar concentration ratio of O to KI is 1: 1.
3. The biomimetic construction method of the Ti @ BiOI-pDA @ CA self-cleaning film as claimed in claim 1, wherein in the step (1), the stirring is magnetic stirring for 0.5-1.5 h.
4. The biomimetic construction method of the Ti @ BiOI-pDA @ CA self-cleaning film as claimed in claim 1, wherein in the step (1), the temperature of the hydrothermal reaction is 170-190 ℃ and the reaction time is 1.0-3.0 h.
5. The biomimetic construction method of the Ti @ BiOI-pDA @ CA self-cleaning film as claimed in claim 1, wherein in the step (2), the concentration of a Tris-HCl solution is 0.605mg/mL, the pH value is 8.5, the mass ratio of Tris-HCl, CA and DA is 0.605:20:1, the volume ratio of deionized water to ethanol is 30:1, the modification time is 4.0-8.0 h, the vacuum drying temperature is 40-60 ℃, and the drying time is 12-24 h.
6. The biomimetic construction method of a Ti @ BiOI-pDA @ CA self-cleaning film as claimed in claim 1, wherein in step (3), the mass ratio of the total mass of the Ti @ BiOI catalyst and the pDA @ CA powder to the DMSO is 13:87, wherein the mass of the Ti @ BiOI catalyst and the pDA @ CA powder is 2: 11.
7. The biomimetic construction method of the Ti @ BiOI-pDA @ CA self-cleaning film as claimed in claim 1, wherein in the step (3), the mechanical stirring time is 6.0-10 h.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910016781.6A CN109794291B (en) | 2019-01-08 | 2019-01-08 | Bionic construction method and application of Ti @ BiOI-pDA @ CA self-cleaning film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910016781.6A CN109794291B (en) | 2019-01-08 | 2019-01-08 | Bionic construction method and application of Ti @ BiOI-pDA @ CA self-cleaning film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109794291A CN109794291A (en) | 2019-05-24 |
| CN109794291B true CN109794291B (en) | 2021-07-20 |
Family
ID=66558673
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910016781.6A Active CN109794291B (en) | 2019-01-08 | 2019-01-08 | Bionic construction method and application of Ti @ BiOI-pDA @ CA self-cleaning film |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109794291B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112522862B (en) * | 2020-11-13 | 2022-02-01 | 南通大学 | Visible light driven antibacterial nanofiber and preparation method and application thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103566776A (en) * | 2013-11-06 | 2014-02-12 | 复旦大学 | Photocatalytic inorganic nanoparticle/polydopamine/polymer self-cleaning composite film and preparation method thereof |
| CN108283932A (en) * | 2017-12-21 | 2018-07-17 | 江苏大学 | A kind of C3N4@Ag3PO4The preparation and application thereof of/PDA@PVDF bionic composite catalyst films |
-
2019
- 2019-01-08 CN CN201910016781.6A patent/CN109794291B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103566776A (en) * | 2013-11-06 | 2014-02-12 | 复旦大学 | Photocatalytic inorganic nanoparticle/polydopamine/polymer self-cleaning composite film and preparation method thereof |
| CN108283932A (en) * | 2017-12-21 | 2018-07-17 | 江苏大学 | A kind of C3N4@Ag3PO4The preparation and application thereof of/PDA@PVDF bionic composite catalyst films |
Non-Patent Citations (3)
| Title |
|---|
| Bactericidal activity and mechanism of Ti-doped BiOI microspheres under visible light irradiation;Jialiang Liang et al;《Colloids and Surfaces B: Biointerfaces》;20160812;第147卷;第308页左栏第3段至右栏第1段 * |
| Bioinspired synthesis of photocatalytic nanocomposite membranes based on synergy of Au-TiO2 and polyamine for degradation of tetracycline under visible light;Chen Wang, et al;《ACS Applied Materials & Interfaces》;20170628;第9卷;第23687-23697页 * |
| Photocatalytic removal of diclofenac by Ti doped BiOI microspheres under visible light irradiation: Kinetics, mechanism, and pathways;Fuyang Liu,et al;《Journal of Molecular Liquids》;20181126;第275卷;第807-814页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109794291A (en) | 2019-05-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103461382B (en) | Silver-loading modified montmorillonite antibacterial agent, preparation method and application thereof | |
| CN111328918B (en) | Preparation method of attapulgite-based pH response antibacterial material | |
| CN102049204B (en) | Metal ion-carried nerchinskite nano tube/polyether sulfone hybridized antibacterial membrane and preparation method thereof | |
| CN105950602B (en) | A kind of microorganism immobilization method and its immobilization flocculated bacteria particle of preparation | |
| WO2005080489A1 (en) | A solution of metal-polymer chelate(s) and applications thereof | |
| CN115340682B (en) | High-bioactivity lignin and preparation method thereof | |
| CN105688992A (en) | Ag/Fe3O4/nano-cellulose tri-element composite material and preparation method thereof | |
| CN111407722B (en) | Silver nanoparticle composite hydrogel, preparation method and application thereof | |
| CN111514882A (en) | Ag-AgCl/tungsten trioxide/graphite-like phase carbon nitride ternary composite photocatalyst and preparation method and application thereof | |
| CN109794291B (en) | Bionic construction method and application of Ti @ BiOI-pDA @ CA self-cleaning film | |
| CN109014236A (en) | A kind of preparation method and applications of the Nano silver grain based on citrus pectin | |
| CN108085312B (en) | Preparation method of environment-friendly organic wastewater biological purifying agent | |
| CN111944799A (en) | Preparation method and application of immobilized particles embedded with thiobacillus denitrificans | |
| CN111066784A (en) | Ag/AgCl/cellulose composite antibacterial material and preparation method and application thereof | |
| CN108358299A (en) | A kind for the treatment of process of ozone catalytic degradation of dye waste water | |
| CN114831136B (en) | Preparation method of oleophylic silver-loaded carbon microsphere | |
| CN113477262B (en) | Preparation method and application of silver chromate/zinc ferrite fibrous composite photocatalyst | |
| CN114377696B (en) | Biofilm-based BiOCl x Br (1-x) /Au/MnO 2 Composite material, preparation method and application thereof | |
| CN109420497A (en) | A kind of InVO4-AgVO3 hetero-junctions catalyst and its preparation method and application | |
| CN108745415B (en) | Poly-o-phenylenediamine modified AgCl/g-C3N4Composite photocatalyst and preparation and application thereof | |
| CN111974367A (en) | Preparation method of polylysine modified cellulose material for adsorbing copper ions | |
| WO2005080490A1 (en) | A solution of metal-polymer chelate(s) and applications thereof | |
| CN111085165A (en) | Preparation method of surface mineralized diatom biomineralized silicon | |
| CN108275767A (en) | A kind for the treatment of process of ozone catalytic degradation dyeing waste water | |
| CN114766512B (en) | Preparation method of inorganic nano material with high efficiency and lasting disinfection and sterilization |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |