Method for analyzing organic components on surface of titanium dioxide

Abstract

The invention relates to the technical field of titanium dioxide production, in particular to a titanium dioxide surface organic component analysis method which comprises the following steps: S1, carrying out elemental analysis on titanium dioxide to be detected so as to respectively determine the original mass percent contents of C and SiO2 in the titanium dioxide to be detected; s2, carrying out reflux extraction on the titanium dioxide to be detected by adopting an organic solvent, carrying out elemental analysis on the titanium dioxide subjected to the reflux extraction so as to respectively determine the mass percent contents of C and SiO2 after the reflux extraction, and carrying out GC-MS detection on an organic phase subjected to the reflux extraction; and S3, determining related information of the organic components on the surface of the titanium dioxide to be detected at least based on a comparison result of the original mass percent contents of the C and the SiO2 and the mass percent contents of the C and the SiO2 after the reflux extraction and a GC-MS detection result of the organic phase after the reflux extraction.

Description

Technical Field

[0001] The invention relates to the technical field of titanium dioxide production, and in particular to a method for analyzing organic components on the surface of titanium dioxide. Background Art

[0002] TiO2 is non-toxic, has a high refractive index, efficient photocatalysis and stable chemical properties, and is widely used in the fields of chemical industry, electronics, energy, water treatment, etc. With the increasing maturity of the synthesis method and modification technology of TiO2, it is more practical to explore and study the surface coating components of TiO2 and the characterization of its effects. Titanium dioxide needs to undergo surface modification to have good application performance. The surface treatment of titanium dioxide is generally divided into inorganic surface modification and organic surface modification. There have been many related research reports on the surface coating modification of TiO2 at home and abroad, but most of them are reports related to the discussion of coating process and the characterization of coating effect, and there are few reports related to the research on its surface coating components. At the same time, titanium dioxide of different product qualities depends to a large extent on organic surface modification technology, which is the key to obtaining high-end titanium dioxide. At present, compared with foreign countries, my country's titanium dioxide products are in a situation of being more but not strong, especially organic surface modification technology. It is urgent to break the status quo of TiO2 surface modification technology.

[0003] Patent application CN 117969331 A discloses a simple analysis method for the type of titanium dioxide organosilicon surface treatment agent. The method analyzes the type of organosilicon modifier of the titanium dioxide to be tested by establishing a relationship model between the adsorption stability and temperature resistance of titanium dioxide and the type of organosilicon surface treatment agent. The method is not suitable for titanium dioxide with SiO2 inorganic coating and titanium dioxide treated with other types of organic modifiers, and can only determine whether it is alkyl silicone oil / hydrogen-containing silicone oil / silane. The analysis results are broad and have great limitations.

[0004] In view of this, there is a need in the prior art for an efficient method for analyzing organic components on the surface of titanium dioxide. Summary of the invention

[0005] The purpose of the present invention is to solve the limitations of existing analytical methods, accelerate the development of new titanium dioxide products and improve existing technologies, and provide a method for analyzing organic components on the surface of titanium dioxide.

[0006] Specifically, the method for analyzing the surface organic components of titanium dioxide described in the present invention includes the following steps: S1. performing elemental analysis on the titanium dioxide to be tested to respectively determine the original mass percentage contents of C and SiO2 in the titanium dioxide to be tested; S2. performing reflux extraction on the titanium dioxide to be tested using an organic solvent, performing elemental analysis on the titanium dioxide after reflux extraction to respectively determine the mass percentage contents of C and SiO2 after reflux extraction, and performing GC-MS detection on the organic phase after reflux extraction; and S3. determining the relevant information of the surface organic components of the titanium dioxide to be tested based at least on the comparison results of the original mass percentage contents of C and SiO2 and the mass percentage contents of C and SiO2 after the reflux extraction and the GC-MS detection results of the organic phase after the reflux extraction.

[0007] In an embodiment of the present invention, step S3 specifically includes: S31. Determining the type of modifier used for surface modification of the titanium dioxide to be tested based on a comparison result of the original mass percentage content of SiO2 and the mass percentage content of SiO2 after the reflux extraction.

[0008] In an embodiment of the present invention, step S3 further specifically includes: S32. Determine whether the difference between the original mass percentage content of C and the mass percentage content of C after the reflux extraction is less than a predetermined value; in response to the difference being less than the predetermined value, the method further includes the following steps: S34. Use an acidic or alkaline solution to react with the titanium dioxide to be tested, and then use an organic solvent to extract the reaction mixture multiple times, perform elemental analysis on the titanium dioxide after the multiple extractions to determine the mass percentage content of C after the multiple extractions, and perform GC-MS detection on the organic phase after the multiple extractions; and S35. Determine the modifier used for surface modification of the titanium dioxide to be tested based on the comparison result of the mass percentage content of C after the reflux extraction and the mass percentage content of C after the multiple extractions, based on the GC-MS detection result of the organic phase after the multiple extractions and the type of the modifier.

[0009] In an embodiment of the present invention, step S34 specifically includes: weighing 20-30g of the titanium dioxide to be tested into a round-bottom flask, adding 50-75ml of an acidic or alkaline solution, adding a stirrer, stirring the reaction for 10-14h, vacuum filtering, washing the upper titanium dioxide with an organic solvent, drying the upper titanium dioxide for elemental analysis, extracting the lower liquid with an organic solvent, and concentrating the organic phase under reduced pressure for GC-MS detection.

[0010] In an embodiment of the present invention, in step S34, when extracting the lower layer of liquid, 8-12 ml of organic solvent is added, the organic phase is collected after stratification, and the extraction is repeated 2-3 times, all the organic phases are collected, and GC-MS detection is performed after reduced pressure concentration.

[0011] In an embodiment of the present invention, in step S34, the acidic solution includes one or more of a 2%-10% hydrofluoric acid aqueous solution, a 10%-20% hydrochloric acid aqueous solution, and a 10%-20% sulfuric acid aqueous solution; the alkaline solution includes one or more of a 10%-20% sodium hydroxide aqueous solution, a 10%-20% potassium hydroxide aqueous solution, and a 10%-20% ammonia aqueous solution.

[0012] In an embodiment of the present invention, step S3 specifically includes: S32. Determine whether the difference between the original mass percentage content of C and the mass percentage content of C after the reflux extraction is less than a predetermined value; S36. In response to the difference being greater than the predetermined value, determine the modifier used for surface modification of the titanium dioxide to be tested based on the comparison result of the original mass percentage content of C and the mass percentage content of C after the reflux extraction, based on the GC-MS detection result of the organic phase after the reflux extraction, and the type of modifier.

[0013] In an embodiment of the present invention, step S2 specifically includes: weighing 20-30g of the titanium dioxide to be tested into a round-bottom flask, adding 30-45ml of an organic solvent, adding a stirrer, inserting a reflux condenser, heating to reflux, stirring and reflux for 4-6h, vacuum filtering, washing the upper titanium dioxide with an organic solvent, drying the upper titanium dioxide, performing elemental analysis, and vacuum concentrating the organic solvent in the filtration bottle for GC-MS detection.

[0014] In an embodiment of the present invention, the organic solvent used for reflux extraction in step S2 includes one or more of dichloromethane, ethyl acetate, N,N-dimethylformamide, and tetrahydrofuran.

[0015] In an embodiment of the present invention, in step S2, the organic solvent used for washing is consistent with the organic solvent used for reflux extraction, and 4-6 ml of the organic solvent used for washing is used each time, and washing is performed 2-4 times.

[0016] The method described in the present invention uses a graded experiment for analysis. An organic solvent is used to reflux extract titanium dioxide to obtain an organic modifier physically adsorbed on the titanium dioxide surface; an acidic or alkaline solution is used to react with titanium dioxide to destroy the chemical bond between the surface modifier and TiO2, and then the reaction mixture is extracted multiple times with an organic solvent to obtain an organic modifier chemically bonded on the titanium dioxide surface. The extract is concentrated and sent to gas chromatography-mass spectrometry (GC-MS), and combined with elemental analysis and GC-MS analysis, more comprehensive information such as the type and characteristic functional groups of the organic components on the surface of titanium dioxide is obtained, and the method has wide applicability, simple operation, and accurate results. The surface organic components of unknown organically modified titanium dioxide are analyzed by the above method, and relatively complete information on its organic modifier can be quickly obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0018] Figure 1a A flow chart of a method for analyzing organic components on the surface of titanium dioxide provided by one embodiment of the present invention; Figure 1b A detailed flow chart of step S3 in the method of the present invention; Figure 2 is a chromatogram-mass spectrum of the organic phase after treatment in step (2) in Example 1 of the present invention; Figure 3a-3d is a chromatogram-mass spectrum of the organic phase after treatment in step (3) in Example 1 of the present invention; Figure 4 is a chromatogram-mass spectrum of the organic phase after treatment in step (2) in Example 2 of the present invention; Figure 5a-5c is a chromatogram-mass spectrum of the organic phase after treatment in step (3) in Example 2 of the present invention; and Figure 6a-6d This is the chromatogram-mass spectrum of the organic phase after treatment in step (2) in Example 3 of the present invention. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0020] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0021] According to the survey, the organic modifiers of titanium dioxide are mainly polyols and silicones, among which silicones mainly involve modified silicone oils and silanes, such as alkyl-modified silicone oils / silanes and polyether-modified silicone oils / silanes. Organic modifiers interact with the active sites on the surface of titanium dioxide through physical adsorption or chemical bonding, and are coated on the surface of TiO2 in the form of monomers or oligomers, changing the properties of TiO2 surface polarity and surface activation energy, thereby improving the dispersibility, surface wettability and weather resistance of titanium dioxide. However, since the organic coating layer on the surface of TiO2 mostly exists in the form of polymers, the amount added is small, and the existence form is also complex, it is difficult to analyze by ordinary analytical methods (such as elemental analysis). Therefore, it is of great significance to develop an efficient method for analyzing the organic components on the surface of titanium dioxide, and to develop new products or improve the original technology by studying the components of the surface coating of excellent TiO2 products, which will promote the improvement of product quality of the entire domestic titanium dioxide industry, the study of the surface modification mechanism of powder materials, and break the status quo of TiO2 surface modification technology.

[0022] The method of the present invention conducts two groups of parallel experiments on the titanium dioxide to be tested. One group directly elutes the organic modifier on the surface of titanium dioxide through physical adsorption: the titanium dioxide is refluxed and extracted with an organic solvent, the organic phase is collected, and it is concentrated and sent for detection; the other group strips the organic modifier on the surface of titanium dioxide through chemical bonding: an acidic or alkaline solution is reacted with the titanium dioxide to destroy the chemical bond between the surface modifier and TiO2, and then the reaction mixture is extracted multiple times with an organic solvent, the organic phase is collected, and it is concentrated and sent for detection.

[0023] Specifically, according to the present invention, a method for analyzing organic components on the surface of titanium dioxide is proposed, such as Figure 1a As shown, it includes the following steps: S1 elemental analysis of the titanium dioxide to be tested to determine the original mass percentage content of C and SiO2 in the titanium dioxide to be tested; S2. Reflux extraction of the titanium dioxide to be tested using an organic solvent, elemental analysis of the titanium dioxide after reflux extraction to determine the mass percentage content of C and SiO2 after reflux extraction, and GC-MS detection of the organic phase after reflux extraction; and S3. Determine the relevant information of the surface organic components of the titanium dioxide to be tested based on at least the comparison results of the original mass percentage content of C and SiO2 and the mass percentage content of C and SiO2 after the reflux extraction and the GC-MS test results of the organic phase after the reflux extraction.

[0024] In an embodiment of the present invention, step S1 specifically includes: weighing a predetermined mass (eg, 5 g) of the titanium dioxide to be tested for elemental analysis. The elemental analysis can be performed on carbon (in terms of C) and silicon (in terms of SiO2).

[0025] In an embodiment of the present invention, Figure 1b As shown, step S3 specifically includes: S31. Determine the type of modifier used for surface modification of the titanium dioxide to be tested based on the comparison result of the original mass percentage content of SiO2 and the mass percentage content of SiO2 after the reflux extraction. If the comparison result shows that the mass percentage content changes significantly, it can be judged that the organic modifier is an organic silicon substance; if there is no obvious change, it may be other types (such as polyols). Optionally, in the subsequent process, the elemental analysis results of SiO2 can also be obtained to further verify the above judgment results.

[0026] In an embodiment of the present invention, Figure 1b As shown, step S3 further specifically includes: S32. Determine whether the difference between the original mass percentage content of C and the mass percentage content of C after the reflux extraction is less than a predetermined value; in response to the difference being less than the predetermined value, the method further includes the following steps: S34. Use an acidic or alkaline solution to react with the titanium dioxide to be tested, then use an organic solvent to extract the reaction mixture multiple times, perform elemental analysis on the titanium dioxide after the multiple extractions to determine the mass percentage content of C after the multiple extractions, and perform GC-MS detection on the organic phase after the multiple extractions; and S35. Determine the modifier used for surface modification of the titanium dioxide to be tested based on the comparison result of the mass percentage content of C after the reflux extraction and the mass percentage content of C after the multiple extractions, based on the GC-MS detection result of the organic phase after the multiple extractions and the type of the modifier.

[0027] In an embodiment of the present invention, step S34 specifically includes: weighing 20-30g of the titanium dioxide to be tested into a round-bottom flask, adding 50-75ml of an acidic or alkaline solution, adding a stirrer, stirring the reaction for 10-14h, vacuum filtering, washing the upper titanium dioxide with an organic solvent, drying the upper titanium dioxide for elemental analysis, extracting the lower liquid with an organic solvent, and concentrating the organic phase under reduced pressure for GC-MS detection.

[0028] In an embodiment of the present invention, in step S34, when extracting the lower layer of liquid, 8-12 ml of organic solvent is added, the organic phase is collected after stratification, and the extraction is repeated 2-3 times, all the organic phases are collected, and GC-MS detection is performed after reduced pressure concentration.

[0029] In an embodiment of the present invention, in step S34, the experimental operation is carried out in a fume hood, and the acidic and alkaline solutions are prepared and used immediately; the acidic solution includes one or more of a 2%-10% hydrofluoric acid aqueous solution, a 10%-20% hydrochloric acid aqueous solution, and a 10%-20% sulfuric acid aqueous solution; the alkaline solution includes one or more of a 10%-20% sodium hydroxide aqueous solution, a 10%-20% potassium hydroxide aqueous solution, and a 10%-20% ammonia aqueous solution. When using a hydrofluoric acid aqueous solution, a plastic round-bottom flask can be used.

[0030] In an embodiment of the present invention, in step S34, the organic solvent is a solvent with good solubility in organic matter, including one or more of dichloromethane (DCM), ethyl acetate (EA), N,N-dimethylformamide (DMF), and tetrahydrofuran (THF). Benzene and toluene solvents are not recommended here because they are highly toxic.

[0031] In the embodiment of the present invention, in step S34, when washing the upper layer of titanium dioxide, 5 ml / time, washing 3 times; the drying temperature of titanium dioxide is 120°C, and drying is 30 minutes; element analysis includes carbon (in terms of C) and silicon (in terms of SiO2).

[0032] In an embodiment of the present invention, Figure 1b As shown, step S3 specifically includes: S32. Determine whether the difference between the original mass percentage content of C and the mass percentage content of C after the reflux extraction is less than a predetermined value; S36. In response to the difference being greater than the predetermined value, determine the modifier used for surface modification of the titanium dioxide to be tested based on the comparison result of the original mass percentage content of C and the mass percentage content of C after the reflux extraction, based on the GC-MS detection result of the organic phase after the reflux extraction, and the type of the modifier.

[0033] In an embodiment of the present invention, step S2 specifically includes: weighing 20-30g of the titanium dioxide to be tested into a round-bottom flask, adding 30-45ml of an organic solvent, adding a stirrer, inserting a reflux condenser, heating to reflux, stirring and reflux for 4-6h, vacuum filtering, washing the upper titanium dioxide with an organic solvent, drying the upper titanium dioxide, performing elemental analysis, and vacuum concentrating the organic solvent in the filtration bottle for GC-MS detection.

[0034] In an embodiment of the present invention, the organic solvent used for reflux extraction in step S2 is a solvent with good solubility in organic matter, including one or more of dichloromethane, ethyl acetate, N,N-dimethylformamide, and tetrahydrofuran. Benzene and toluene solvents are not recommended here because they are highly toxic.

[0035] In an embodiment of the present invention, in step S2, the organic solvent used for washing is consistent with the organic solvent used for reflux extraction, and 4-6 ml of the organic solvent used for washing is used each time, and washing is performed 2-4 times.

[0036] In an embodiment of the present invention, in step S2, the heating reflux temperature is 40-100°C; the titanium dioxide drying temperature is 120°C, and the drying time is 30 minutes; and the elemental analysis is performed on carbon (in terms of C) and silicon (in terms of SiO2).

[0037] Based on the above elemental analysis and GC-MS analysis results, more comprehensive information such as the type of organic components on the surface of the titanium dioxide to be tested and characteristic functional groups can be obtained.

[0038] The present invention will be further described and illustrated below in conjunction with the embodiments of the present invention.

[0039] Example 1 The method for analyzing the organic components on the surface of titanium dioxide described in this embodiment comprises the following steps: (1) Weigh 5 g of the titanium dioxide 1 to be tested for elemental analysis including carbon and silicon (sample number 1-1, as shown in Table 1, the percentage content of C is 0.482%, and the percentage content of SiO2 is 1.72%); (2) Weigh 20 g of the titanium dioxide 1 to be tested into a round-bottom flask, add 30 ml of EA, add a stirrer, insert a reflux condenser, heat to 80 ° C and reflux, stir and reflux for 5 hours, filter under reduced pressure, wash the upper titanium dioxide with EA, 5 ml / time, wash 3 times, dry the upper titanium dioxide at 120 ° C for 30 minutes and send it for elemental analysis including carbon and silicon (sample number 1-2, as shown in Table 1, the percentage content of C is 0.475%, and the percentage content of SiO2 is 1.68%, indicating that the organic modifier on the surface of the titanium dioxide 1 to be tested is almost not extracted, and the modifier interacts with TiO2 through chemical bonding. Therefore, the titanium dioxide needs to be treated with HF aqueous solution), concentrate the EA in the filtration bottle under reduced pressure and send it for GC-MS detection (sample number 1-3, as shown in Table 1). Figure 2 As shown in the chromatogram-mass spectrum, except for the obvious solvent peak, the other organic component peaks are messy and the signals are weak); (3) Weigh 20g of the titanium dioxide 1 to be tested into a plastic round-bottom flask, add 50ml of 2% HF aqueous solution, add a stirrer, stir and react for 12h, filter under reduced pressure, wash the upper titanium dioxide with EA, 5ml / time, wash 3 times, dry the upper titanium dioxide at 120℃ for 30 minutes and send it for elemental analysis including carbon and silicon (sample No. 1-4, as shown in Table 1, the percentage content of C is 0.054%, the percentage content of SiO2 is 0.246%, at this time the organic components on the surface of the titanium dioxide are stripped off, and it can be determined that the modifier is organic silicon). After the lower liquid is extracted 3 times with 10ml EA, all the organic phases are collected, the organic phases are concentrated under reduced pressure and sent to GC-MS for detection (sample No. 1-5, because the HF solution can destroy multiple Si-O bonds, the organic components in this sample are fragments of the stripped organic modifier, and the core skeleton information of the organic modifier can be obtained by analysis, such as Figure 3a-3d As shown, there are multiple signal peaks of different intensities in the chromatogram-mass spectrum, which, combined with mass spectrometry analysis, include phenyl fragments, long-chain silane polymer fragments, and silane polymer fragments containing silicon hydrogen); (4) According to the results of elemental analysis and GC-MS analysis, the organic modifier of the titanium dioxide 1 to be tested is an organosilicon type, and the main component is phenyl alkyl modified silane containing active silicon hydrogen functional groups.

[0040] Example 2 The method for analyzing the organic components on the surface of titanium dioxide described in this embodiment comprises the following steps: (1) Weigh 5 g of the titanium dioxide 2 to be tested for elemental analysis including carbon and silicon (sample number 2-1, as shown in Table 1, the percentage content of C is 0.260%, and the percentage content of SiO2 is 0.01%); (2) Weigh 20 g of the titanium dioxide 2 to be tested into a round-bottom flask, add 30 ml of THF, add a stirrer, insert a reflux condenser, heat to 67 ° C and reflux, stir and reflux for 4 hours, filter under reduced pressure, wash the upper titanium dioxide with THF, 6 ml / time, wash twice, dry the upper titanium dioxide at 120 ° C for 30 minutes and send it for elemental analysis including carbon and silicon (sample number 2-2, as shown in Table 1, the percentage content of C is 0.250%, the percentage content of SiO2 is 0%, and the carbon content changes less than 20%. The modifier and TiO2 interact through chemical bonding, so the titanium dioxide needs to be treated with HF aqueous solution), concentrate the THF in the filtration bottle under reduced pressure and send it for GC-MS detection (sample number 2-3, as shown in Table 1). Figure 4 As shown, in the chromatogram-mass spectrum, there are almost no other organic component peaks except the obvious solvent peak); (3) Weigh 20g of the titanium dioxide 2 to be tested into a round-bottom flask, add 50ml of 10% HCl aqueous solution, add a stirrer, stir and react for 14h, filter under reduced pressure, wash the upper titanium dioxide with THF, 5ml / time, wash 3 times, dry the upper titanium dioxide at 120℃ for 30 minutes and send it for elemental analysis including carbon and silicon (sample number 2-4, as shown in Table 1, the percentage content of C is 0.080%, the percentage content of SiO2 is 0.01%, it can be determined that the organic modifier of the titanium dioxide to be tested is not silicone), extract the lower liquid with 10ml THF 3 times, collect all the organic phases, concentrate the organic phase under reduced pressure and send it for GC-MS detection (sample number 2-5, as shown in Table 1 Figure 5a-5c As shown, a main peak can be observed in the chromatogram-mass spectrum, and the matching scores of the mass spectrum corresponding to the main peak and trimethylolpropane are both 97%, so the substance can be determined to be trimethylolpropane); (4) According to the results of elemental analysis and GC-MS analysis, the organic modifier of the titanium dioxide 2 to be tested is a polyol, specifically, trimethylolpropane.

[0041] Example 3 The method for analyzing the organic components on the surface of titanium dioxide described in this embodiment comprises the following steps: (1) Weigh 5 g of the titanium dioxide 3 to be tested for elemental analysis including carbon and silicon (sample number 3-1, as shown in Table 1, the percentage content of C is 0.665%, and the percentage content of SiO2 is 1.56%); (2) Weigh 30g of the titanium dioxide 3 to be tested into a round-bottom flask, add 45ml of DCM, add a stirrer, insert a reflux condenser, heat to 40℃ and reflux, stir and reflux for 4h, filter under reduced pressure, wash the upper titanium dioxide with DCM, 6ml / time, wash 4 times, dry the upper titanium dioxide at 120℃ for 30 minutes and send it for elemental analysis including carbon and silicon (sample number 3-2, as shown in Table 1, the percentage content of C is 0.103%, and the percentage content of SiO2 is 0.38%. Through extraction, the carbon content in the titanium dioxide was reduced by 85%, which determined that the modifier was physically adsorbed on the surface of the titanium dioxide, and there was no need to treat the titanium dioxide with acidic or alkaline aqueous solvents. At the same time, the inorganic coating of the titanium dioxide may contain SiO2), concentrate the DCM in the filtration bottle under reduced pressure and send it for GC-MS detection (sample number 3-3, as shown in Table 1). Figure 6a-6d As shown, obvious main peaks can be observed in the chromatogram-mass spectrum, and the matching scores of the mass spectra corresponding to each main peak and the dimethylsilane polymer are all above 93%). (3) According to the results of elemental analysis and GC-MS analysis, the organic modifier of the titanium dioxide 3 to be tested is dimethyl silicone oil.

[0042] Table 1 Elemental analysis results of the titanium dioxide to be tested

[0043] The amount of organic modifier added to titanium dioxide is generally 0.1-2% of the mass of titanium dioxide. The amount added is small, and the interaction with titanium dioxide is complex and difficult to detect. Therefore, it is necessary to use a variety of detection methods in combination for analysis. The purpose of elemental analysis in the present invention is, on the one hand, to determine whether the organic modifier is an organic silicon substance (if the silicon content of titanium dioxide changes before and after the treatment in step (2), it means that the modifier must be an organic silicon substance. If there is no obvious change, it may be other types); on the other hand, it can evaluate the stripping effect of organic matter on the surface of titanium dioxide, which is evaluated based on the change in carbon content before and after the treatment of titanium dioxide. If the carbon content in titanium dioxide does not change significantly (less than 20%) after step (2), and the liquid phase spectrum in the GC-MS analysis report in step (2) has a small number of peaks and weak peak intensity, it means that the organic modifier on the surface of titanium dioxide mostly interacts with TiO2 in the form of chemical bonding, and extraction alone cannot effectively strip the organic substance. The organic substance can only be stripped by breaking the chemical bonds with an acidic or alkaline solution in step (3). If the carbon content in the titanium dioxide drops sharply (greater than 80%) after step (2), and the number of peaks in the liquid phase spectrum in the GC-MS analysis report is single and the mass spectrometry analysis results are clear, then step (3) is not necessary. This indicates that the organic modifier on the surface of the titanium dioxide reacts with TiO2 in the form of physical adsorption and can be effectively stripped off by extraction.

[0044] GC-MS is a technology that combines a gas chromatograph (GC) with a mass spectrometer (MS) through an appropriate interface and uses powerful computer technology to perform coupled analysis. The working principle is to use GC to separate the various chemical components in the sample mixture, and then use MS to measure the mass-to-charge ratio (m / z) of the charged particles in turn, thereby determining the molecular weight and elemental composition of each chemical component, and clarifying the chemical structure of the molecule, which can be used for qualitative and quantitative analysis. The present invention uses GC-MS analysis to quickly obtain the structural information of the stripped organic matter in a database that stores nearly 300,000 standard mass spectra of compounds.

[0045] The method for analyzing the organic components on the surface of titanium dioxide provided by the present invention can obtain more comprehensive information such as the type and characteristic functional groups of the organic components on the surface of titanium dioxide, and has wide applicability, simple operation, accurate results, and good application prospects.

[0046] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for analyzing organic components on the surface of titanium dioxide, characterized in that: The following steps are involved: S1 elemental analysis of the titanium dioxide to be tested to determine the original mass percentage content of C and SiO2 in the titanium dioxide to be tested; S2. The titanium dioxide to be tested was subjected to reflux extraction using an organic solvent, and elemental analysis was performed on the titanium dioxide after reflux extraction to determine the mass percentage content of C and SiO2 after reflux extraction, respectively, and the organic phase after reflux extraction was subjected to GC-MS detection; as well as S3. Determine the relevant information of the surface organic components of the titanium dioxide to be tested based on at least the comparison results of the original mass percentage content of C and SiO2 and the mass percentage content of C and SiO2 after the reflux extraction and the GC-MS test results of the organic phase after the reflux extraction.

2. The method for analyzing organic components on the surface of titanium dioxide according to claim 1, characterized in that: Step S3 specifically includes: S31. Determining the type of modifier used for surface modification of the titanium dioxide to be tested based on the comparison result of the original mass percentage content of SiO2 and the mass percentage content of SiO2 after the reflux extraction.

3. The method for analyzing organic components on the surface of titanium dioxide according to claim 2, characterized in that: Step S3 further specifically includes: S32. Determine whether the difference between the original mass percentage content of C and the mass percentage content of C after the reflux extraction is less than a predetermined value; In response to the difference being less than the predetermined value, the method further comprises the following steps: S34. A reaction is performed with an acidic or alkaline solution and the titanium dioxide to be tested, and then the reaction mixture is extracted multiple times with an organic solvent, and elemental analysis is performed on the titanium dioxide after multiple extractions to determine the mass percentage content of C after multiple extractions, and the organic phase after multiple extractions is subjected to GC-MS detection; and S35. Determine a modifier for surface modification of the titanium dioxide to be tested based on the comparison result of the mass percentage content of C after the reflux extraction and the mass percentage content of C after the multiple extractions, based on the GC-MS test results of the organic phase after the multiple extractions, and the type of the modifier.

4. The method for analyzing organic components on the surface of titanium dioxide according to claim 3, characterized in that: Step S34 specifically includes: weighing 20-30g of the titanium dioxide to be tested into a round-bottom flask, adding 50-75ml of an acidic or alkaline solution, adding a stirrer, stirring the reaction for 10-14h, vacuum filtering, washing the upper titanium dioxide with an organic solvent, drying the upper titanium dioxide for elemental analysis, extracting the lower liquid with an organic solvent, and concentrating the organic phase under reduced pressure for GC-MS detection.

5. The method for analyzing organic components on the surface of titanium dioxide according to claim 4, characterized in that: In step S34, when extracting the lower layer of liquid, 8-12 ml of organic solvent is added, the organic phase is collected after stratification, and the extraction is repeated 2-3 times, all the organic phases are collected, and GC-MS detection is performed after reduced pressure concentration.

6. The method for analyzing organic components on the surface of titanium dioxide according to claim 4, characterized in that: In step S34, the acidic solution includes one or more of a 2%-10% hydrofluoric acid aqueous solution, a 10%-20% hydrochloric acid aqueous solution, and a 10%-20% sulfuric acid aqueous solution; the alkaline solution includes one or more of a 10%-20% sodium hydroxide aqueous solution, a 10%-20% potassium hydroxide aqueous solution, and a 10%-20% ammonia aqueous solution.

7. The method for analyzing organic components on the surface of titanium dioxide according to claim 2, characterized in that: Step S3 specifically includes: S32. Determine whether the difference between the original mass percentage content of C and the mass percentage content of C after the reflux extraction is less than a predetermined value; S36. In response to the difference being greater than the predetermined value, determining a modifier for surface modification of the titanium dioxide to be tested based on a comparison result of the original mass percentage content of C with the mass percentage content of C after the reflux extraction, based on a GC-MS test result of the organic phase after the reflux extraction, and the type of modifier.

8. The method for analyzing organic components on the surface of titanium dioxide according to claim 1, characterized in that: Step S2 specifically includes: weighing 20-30g of the titanium dioxide to be tested into a round-bottom flask, adding 30-45ml of an organic solvent, adding a stirrer, inserting a reflux condenser, heating to reflux, stirring and reflux for 4-6h, vacuum filtering, washing the upper titanium dioxide with an organic solvent, drying the upper titanium dioxide, performing elemental analysis, and vacuum concentrating the organic solvent in the filtration bottle for GC-MS detection.

9. The method for analyzing organic components on the surface of titanium dioxide according to claim 8, characterized in that: The organic solvent used for reflux extraction in step S2 includes one or more of dichloromethane, ethyl acetate, N,N-dimethylformamide, and tetrahydrofuran.

10. The method for analyzing organic components on the surface of titanium dioxide according to claim 9, characterized in that: In step S2, the organic solvent used for washing is consistent with the organic solvent used for reflux extraction, and 4-6 ml of the organic solvent used for washing is used each time, and washing is performed 2-4 times.

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