CN104198466A - A kind of method of measuring Ti content in TiO2 photocatalyst - Google Patents

Abstract

The invention discloses a method for measuring Ti content in a _TiO2 photocatalyst, belonging to the field of chemical testing. The method of the present invention is as follows: add 10~100mg carrier catalyst in the polytetrafluoroethylene microwave digestion tube, add 1~10ml concentration of 98% concentrated sulfuric acid and 1~10ml concentration of 30% hydrogen peroxide, place in microwave digestion tube Heat the digestion reaction in the instrument, control the reaction temperature at 140~200°C and the reaction time at 25~55min; after the reaction is completed, filter the digestion solution and set the volume to 50ml, and measure the Ti content of the supernatant by ICP-OES. The invention provides a quick and easy method for measuring the content of Ti in the TiO ₂ catalyst by acidifying the carrier TiO ₂ catalyst and pretreatment with microwave digestion to finally convert the TiO ₂ into soluble ionic Ti. This method is also suitable for the determination of Ti content in catalysts of other forms, such as TiO ₂ nanosheet colloid, TiO ₂ nanotube, TiO ₂ film, etc., and the determination of Ti content in TiO ₂ catalyst after multiple reactions, and has a wide range of applications.

Description

A kind of method of measuring Ti content in TiO2 photocatalyst

technical field

The invention relates to the field of chemical testing, and relates to a method for measuring Ti content in _TiO2 photocatalysts.

Background technique

In recent years, water pollution and air pollution have become increasingly serious. In order to effectively remove various pollutants such as refractory organic matter, SO ₂ , NO _x , etc., adsorption, chemical oxidation and biological methods have been applied in various fields. As an advanced oxidation technology, TiO ₂ photocatalytic technology has attracted widespread attention. It is low in cost, safe, non-toxic, stable, and can react at room temperature without adding other chemical reagents. It can almost non-selectively oxidize environmental pollutants. , and the final products are CO ₂ , H ₂ O, NO ₃ ^- and SO ₄ ^2- , etc., which will not cause secondary pollution, making it more and more important as an excellent photocatalyst.

The content of TiO ₂ in the catalyst active center is an important index to measure the catalyst activity. In general research, the content of TiO ₂ in catalysts with different forms is usually controlled according to the content of Ti precursors such as titanium alkoxide added in the preparation process to control the content of TiO ₂ in the prepared photocatalyst, but material loss is inevitable during the preparation process , resulting in a deviation in the content calculation.

At present, the determination methods of _TiO2 include colorimetry, titration and inductively coupled plasma emission spectrometry, for example, GB/T3654.8-2008 uses chromotropic acid photometry to determine the titanium content in ferroniobium, GB/T6730.23- In 2006, ferrous ammonium sulfate titration method was used to measure titanium content, but the results of titration and colorimetry are subject to many interference factors and large errors, especially not suitable for the determination of low-content titanium, and the test cycle is long, not suitable for large quantities of samples In the pretreatment process of samples, the method of enhanced acid acidification combined with electric heating plate heating (Ju Lipei et al., 2013) or strong alkali melting-metal reduction method (patent application No. 2012103888190) is usually used, which is time-consuming long.

This test method aims to establish a method for rapid pretreatment of _TiO2 photocatalyst and determination of Ti content. Specifically, the _TiO2 photocatalyst is pretreated by strong acid acidification-microwave digestion method, and all solid _TiO2 is converted into soluble ions The state of Ti can be easily determined by inductively coupled plasma optical emission spectrometer (ICP-OES).

Contents of the invention

Aiming at the difficulty of directly measuring the Ti content in the _TiO2 catalyst, the present invention provides a strong acid dissolution combined with microwave digestion method to pretreat the catalyst, and then use the ICP-OES method to measure the Ti content. This method is simple and easy to implement. Described method realizes by following way:

Add 10~100 mg of TiO ₂ catalyst to the polytetrafluoroethylene microwave digestion tube, add 1~10 ml of concentrated sulfuric acid with a concentration of 98% and 1~10 ml of hydrogen peroxide with a concentration of 30%, and then place it in a microwave digestion apparatus , carry out the digestion reaction under the heating power of 800W (the conditions are: step 1, heating time 5-15 min, target temperature 120-160°C, no hold; step 2, target temperature 170-200°C, holding time 20-40 min), The cooled digestate was filtered and the volume was adjusted to 50 ml, and the titanium element was determined by ICP-OES.

The present invention has the following advantages compared with conventional assay methods:

(1) A strong acid acidification combined with microwave digestion method was proposed to pretreat TiO ₂ photocatalysts, which is simple and rapid;

(2) This method is not only applicable to the determination of _TiO2 content in supported catalysts, but also suitable for the determination of Ti content in other forms such as _TiO2 nanosheet colloid, _TiO2 nanotube, _TiO2 film, etc., and has a wide range of applications;

(3) This method can determine the Ti content in the TiO ₂ catalyst after multiple reactions.

Detailed ways

The reagents used in the examples include:

98% concentrated sulfuric acid, superior grade; 30% hydrogen peroxide, premium grade; Titanium dioxide (100%), analytically pure; pure water; Titanium standard solution, 1000 mg/ml (National Nonferrous Metals and Electronic Materials Analysis and Testing Center); 65% concentrated nitric acid, superior grade.

Example 1:

Embodiment 1 relates to the preparation of Ti standard solution, the drawing of standard working curve and containing carrier catalyst TiO _2The mensuration, specifically as follows:

(1) Prepare the titanium standard solution and draw the standard working curve: dilute the titanium standard solution with 2% nitric acid to constant volume, and prepare titanium ion concentrations of 0.1 mg/ml, 0.5 mg/ml, 1 mg/ml, and 2 mg respectively /ml, 5 mg/ml, 10 mg/ml series of titanium standard working solutions, the linear regression coefficient of the standard working curve R ² =0.9999;

(2) Digestion of supported catalyst samples: Weigh the TiO ₂ photocatalyst with fly ash as the carrier and place it in a polytetrafluoroethylene microwave digestion tube, add 6 ml of 98% concentrated sulfuric acid and 4 ml of 30% For hydrogen peroxide, carry out microwave digestion in a microwave digestion apparatus (conditions: step 1, heat up for 5 minutes, target temperature 140°C; step 2, target temperature 190°C, keep warm for 25 minutes), filter and dilute to 50 ml after the reaction;

(3) Determination: Take the solution after constant volume in the previous step, pass it through a 0.45 mm polyethersulfone filter membrane, use an inductively coupled plasma optical emission spectrometer (ICP-OES) for detection, and calculate through the standard curve obtained in the sample to obtain Titanium content.

Example 2:

(1) Prepare titanium standard solution and draw standard working curve: Dilute the single standard solution of titanium with 2% nitric acid to constant volume, and prepare titanium ion concentrations of 0.1 mg/ml, 0.5 mg/ml, 1 mg/ml, 2 mg/ml, 5 mg/ml, 10 mg/ml series of titanium standard working solutions, the linear regression coefficient of the standard working curve R ² =0.9999;

(2) Digest TiO ₂ nanosheet colloid solution: Take 1 ml of TiO ₂ nanosheet colloid solution with different concentrations in a polytetrafluoroethylene microwave digestion tube, add 5 ml of 98% concentrated sulfuric acid and 3 ml of 30% Hydrogen peroxide, react in a microwave digestion apparatus (conditions: step 1, heat up for 8 minutes, target temperature 150 °C; step 2, target temperature 170 °C, keep warm for 35 min), after cooling, dilute to 50 ml;

(3) Determination: Take the solution after constant volume in the previous step, use the inductively coupled plasma optical emission spectrometer (ICP-OES) to detect, and calculate the content of titanium element in the colloidal solution through the standard curve obtained therein.

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Claims (6)

1. one kind to TiO ₂the assay method of Ti content in photocatalyst, that application strong acid acidifying United microwave resolution method is carried out pre-service to carried catalyst, and then titanium ion concentration is measured, it is characterized in that described method concrete steps are: first in teflon micro-wave digestion pipe, add 10 ~ 100 mg TiO ₂catalyzer, then add the hydrogen peroxide that the concentrated sulphuric acid that 1 ~ 10 ml concentration is 98% and 1 ~ 10 ml concentration are 30%, be then placed in microwave dissolver, (condition is: step 1 under 800W heating power, to clear up reaction, heating-up times 5 ~ 15 min, 140 ~ 160 ℃ of target temperatures, do not keep; Step 2,170 ~ 200 ℃ of target temperatures, insulation 20 ~ 40 min), digestion solution is filtered and is settled to 50 ml after cooling, utilize ICP-OES to carry out the mensuration of titanium elements.

2. a kind of mensuration TiO according to claim 1 ₂the assay method of Ti content in catalyzer, is characterized in that the catalyzer amount of clearing up is 10 ~ 100 mg.

3. a kind of mensuration TiO according to claim 1 ₂the assay method of Ti content in catalyzer, is characterized in that in described acidification that 98% concentrated sulphuric acid addition is 1 ~ 10 ml, and the addition of 30% hydrogen peroxide is 1 ~ 10 ml.

4. a kind of mensuration TiO according to claim 1 ₂the assay method of Ti content in catalyzer, micro-wave digestion temperature of reaction is 140 ~ 200 ℃.

5. a kind of mensuration TiO according to claim 1 ₂the assay method of Ti content in catalyzer, the micro-wave digestion reaction time is 25 ~ 55 min.

6. a kind of mensuration TiO according to claim 1 ₂the assay method of Ti content in catalyzer, constant volume test again after reaction finishes rear digestion solution and need filter.