CN111646536A

CN111646536A - Method for directly and photoelectrically degrading basic dye based on FTO conductive glass

Info

Publication number: CN111646536A
Application number: CN202010560056.8A
Authority: CN
Inventors: 陈毅挺; 黄露; 李艳霞; 邱桢丽
Original assignee: Minjiang University
Current assignee: Minjiang University
Priority date: 2020-06-18
Filing date: 2020-06-18
Publication date: 2020-09-11

Abstract

The invention belongs to the technical field of dye wastewater treatment, and particularly relates to a method for directly and photoelectrically degrading a basic dye based on FTO conductive glass. The invention takes FTO conductive glass as an anode, a graphite electrode as a cathode, and electrolyzes alkaline dye simulated dye wastewater, and researches the influence of the factors on the degradation and decoloration of the alkaline dye simulated dye wastewater by determining the maximum absorption wavelength of the alkaline dye and a standard curve of the alkaline dye solution and respectively controlling the factors such as the pH value of the simulated alkaline dye wastewater, the adding amount of a conductive medium NaCl, the adding amount of photocatalyst nano TiO2, the initial concentration of the alkaline dye wastewater, the magnitude of applied voltage and the like in the experimental process, so as to determine the optimal value of each factor. And simultaneously, the decoloring effect and the degradation mechanism of the decoloration are observed by means of ultraviolet and visible spectrums, fluorescence spectrums, infrared spectrums and the like.

Description

Method for directly and photoelectrically degrading basic dye based on FTO conductive glass

Technical Field

The invention belongs to the technical field of dye wastewater treatment, and particularly relates to a method for directly and photoelectrically degrading a basic dye based on FTO conductive glass.

Background

In recent decades, the dye production and printing and dyeing industry has been rapidly developed, but the annual total discharge amount of dye wastewater is getting bigger and bigger, and the dyes are developed towards the directions of oxidation resistance, antibiotic resistance, degradation resistance and the like, and the varieties are also in endlessly. The waste water contains various complex compounds such as dye, dyeing assistant, stabilizer and the like, and some harmful substances even cause cancer, mutation and distortion. Dye wastewater is a difficult-to-treat industrial wastewater due to the characteristics of high biological toxicity, high COD, deep chromaticity, stable structure, difficult biochemical degradation and the like. The traditional water treatment adopts the processes of adsorption, flocculation, air flotation, reverse osmosis, biochemistry and the like which are only used for transferring or separating and enriching pollutants, and has the possibility of bringing secondary pollution, so the traditional method is usually 'treating the symptoms and not the root causes'. With the development of wastewater treatment technology, a single treatment mode cannot deal with a large amount of production wastewater, and various combinations of traditional treatment methods can achieve better treatment effect and economic benefit.

Currently in TiO form₂Although many research reports exist on the photocatalytic technology used as a catalyst, few photocatalytic technologies can be practically applied because the photo-generated electrons and holes are easily recombined, which reduces the quantum yield and the photocatalytic efficiency. The electrochemical degradation method can provide hydroxyl radicals, and an electric field can effectively separate photo-generated electrons from holes. Therefore, if the two are combined, a good synergistic effect can be generated, and the degradation of the refractory organic wastewater containing the basic dye wastewater can be realized quickly and efficiently without secondary pollution, so that the method is a wastewater treatment method with a great development prospect.

Basic dyes, also known as cationic dyes. The basic black is azo and methine dye containing nitrogen heterocycle, is black when dissolved in water and ethanol, is used for dyeing fabrics such as silk, hemp, acrylic fiber, leather and the like, and has high blackness and good color fastness. Basic scarlet, named basic scarlet and cationic red GTL, and can be used for dyeing and printing cotton, acrylon, silk, leather, paper, feather, wheat straw, bamboo, wood, cane, etc

The invention combines the photocatalysis technology and the electrochemical oxidation technology, utilizes the synergistic effect between the photocatalysis technology and the electrochemical oxidation technology, develops the treatment idea of cationic dye wastewater such as basic dye and the like, and provides reference for the treatment of the basic dye wastewater.

Disclosure of Invention

The invention aims to provide a method for directly and photoelectrically degrading basic dye based on FTO conductive glass. The method takes FTO conductive glass as an anode and a graphite electrode as a cathode, degrades basic dye simulated dye wastewater, inspects the influence of various influencing factors on the decoloration rate of the basic dye, determines the optimal decoloration process conditions and carries out preliminary research on the photoelectric degradation mechanism of the basic dye.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for directly and photoelectrically degrading basic dye based on FTO conductive glass specifically comprises the following steps:

(1) fixing a graphite electrode and FTO conductive glass on two sides of a plastic square electrolytic tank by using transparent adhesive tapes respectively, taking the FTO conductive glass as an anode and the graphite electrode as a cathode, and preparing simulated alkaline dye wastewater by using a buffer solution;

(2) adding electrolyte NaCl and photocatalyst nano TiO into waste water₂The square electrolytic cell is placed on a magnetic heating stirrer in a darkroom of the ultraviolet curing device, the positive and negative electrodes of a digital voltage-stabilizing and current-stabilizing power supply are respectively connected with an FTO conductive glass electrode and a graphite electrode, the power supply is started to adjust the voltage, and meanwhile, the power supply of the ultraviolet curing device is started to carry out a wastewater photoelectric degradation experiment.

The invention respectively controls the pH value of the simulated basic dye wastewater, the adding amount of a conductive medium NaCl and the photocatalyst nano TiO₂Addition amount of basic dyeThe method comprises the following steps of (1) researching the influence of factors such as initial concentration of wastewater, applied voltage and the like on degradation and decoloration of basic dye wastewater, and determining the optimal value of each factor. And simultaneously, the decoloring effect and the degradation mechanism of the decoloration are observed by means of ultraviolet and visible spectrums, fluorescence spectrums, infrared spectrums and the like.

Further, when the basic dye is basic scarlet, the pH value is 7 in the environment, the adding amount of NaCl is 1g/L, and the catalyst TiO₂The adding amount is 0.1g/L, the applied voltage is 8V, the photoelectric decolorization is carried out on the basic scarlet with the initial concentration of 10mg/L for 60min, and the decolorization rate can reach 97.70%. Hydroxyl radicals estimated to be generated by photoelectricity synergy play a main role in the wastewater decolorization process.

Further, when the basic dye is basic black, TiO₂When the dosage is 0.1g/L, NaCl and the concentration is 0.5g/L, an external voltage of 12V is applied to the solution of the alkaline black (the initial concentration is 15mg/L, the pH is 9), the solution is degraded for 60min under ultraviolet light, and the decolorization rate reaches 95.04%.

The invention has the following remarkable advantages:

compared with photocatalysis and electrochemical degradation, under the same condition, the time required by the photoelectrocatalysis to reach the maximum decolorization rate is shorter than that of the photocatalysis and electrochemical degradation, and the decolorization effect of the photoelectrocatalysis is more than the simple superposition of the decolorization effects of the photocatalysis and the electrochemical degradation. Taking alkaline black as an example, as shown in fig. 1, the maximum decolorization value can be reached by photoelectrocatalysis within about 20min, the maximum decolorization value can be reached by photoelectrocatalysis and electrochemical degradation within about 40min and 60min respectively, and even after 60min, the decolorization rate of photoelectrocatalysis is still larger than the sum of the decolorization rates of photocatalysis and electrochemical degradation, so that the visible light catalysis and the electrochemical degradation play a synergistic role, and the decolorization rate of the alkaline black is improved. Meanwhile, in the use of the photocatalyst, the method does not need to carry out modification and other treatments on the photocatalyst, thereby greatly simplifying the steps of the experiment. But using FTO glass as anode directly, and BDD, Ti/PbO₂、Ti-RuO₂-IrO₂Compared with the electrode, the decoloration rate of the alkaline black can reach more than 90 percent, but the time for reaching the maximum decoloration rate is respectively 20min, 35 min, 30 min and 50min, so that the FTO glass is used as the anode for the alkaline blackThe time for decoloring is short, and the FTO glass can be directly obtained from commercial channels, so that the FTO glass is convenient and easy to obtain.

The research organically combines electrocatalytic oxidation and photocatalytic oxidation, discusses the optimal process conditions of photoelectrocatalysis, and conjectures the degradation mechanism. The method has important scientific significance and practical significance for efficiently and economically treating dye wastewater, saving energy, reducing emission, protecting ecological environment and human health.

Drawings

FIG. 1 influence of different degradation modes on the degradation of alkaline black;

FIG. 2 is a graph of UV-Vis spectra before and after degradation of basic black;

FIG. 3 TiO₂Influence of concentration on the alkali black decolorization rate;

FIG. 4 effect of initial pH on alkali black decolorization rate;

FIG. 5 the effect of applied voltage on the alkali black bleaching rate;

FIG. 6 the effect of NaCl usage on the alkali black decolorization rate;

FIG. 7 effect of degradation time on alkali black decolorization rate;

FIG. 8 effect of initial dye concentration on basic black decolorization ratio;

FIG. 9 Effect of pH on basic scarlet decolorization rate;

FIG. 10 Effect of NaCl concentration on basic Red discoloration rate;

FIG. 11 TiO₂Influence of concentration on the decolorization rate of basic scarlet;

FIG. 12 is a graph showing the relationship between the initial concentration of basic bright red pigment and the decolorization ratio;

FIG. 13 shows the relationship between the applied voltage and the decolorization ratio of the waste water of the basic scarlet dye.

Detailed Description

For further disclosure, but not limitation, the present invention is described in further detail below with reference to examples.

Example 1

A method for directly photodegrading alkaline black based on FTO conductive glass comprises the following specific steps:

(1) in plastic square electrolytic tankFixing graphite electrode and FTO conductive glass with transparent adhesive tape at both sides, respectively, using FTO conductive glass as anode, graphite electrode as cathode, and Na₂HPO₄-NaH₂PO₄Preparing 100mL of simulated basic dye wastewater by using a buffer solution;

(2) adding electrolyte NaCl and photocatalyst nano TiO into waste water₂Putting a square electrolytic tank on a magnetic heating stirrer in a darkroom of an ultraviolet curing device, respectively connecting the positive and negative electrodes of a digital voltage-stabilizing and current-stabilizing power supply with an FTO conductive glass electrode and a graphite electrode, starting the power supply to adjust the voltage, simultaneously starting the power supply of the ultraviolet curing device, pulling a baffle plate open after the illumination intensity is stable, and carrying out a wastewater degradation experiment.

Sampling and centrifuging at regular intervals, taking distilled water as reference, measuring the absorbance under the maximum absorption wavelength by using a 721 type visible spectrophotometer, and calculating the decolorization rate by the following formula:

wherein R represents the decolorization ratio, A₀And A represents the absorbance of the solution before and after degradation, respectively.

1.1 determination of the monitoring wavelength

A40 mg/L alkaline black solution is prepared, and the ultraviolet-visible spectrum before and after degradation is scanned within a wavelength interval of 200 to 800nm, and the result is shown in figure 2. As can be seen from FIG. 2, the absorption is strongest at 580nm, and the absorbance of the wavelength after degradation is substantially close to 0, so 580nm is selected as the wavelength monitored in the degradation and decolorization process.

1.2 TiO₂Influence of dosage

The pH value of the phosphate buffer solution is adjusted to 10 by concentrated NaOH, the adjusted 85mL of phosphate buffer solution and 5mL of mother liquor are stirred uniformly, and sampling is carried out to measure the initial absorbance. Adding 0.1g/L NaCl, TiO₂The concentrations are 0.05, 0.10, 0.20 and 0.30g/L respectively. Applying voltage 2V, degrading under ultraviolet light for 80min, sampling every 5min before 20min, and sampling every 20min after 20 min. 8mL of the sample is taken each time, the sample is centrifuged at 3200r/min, the supernatant is taken to measure the absorbance, and the decolorization rate is calculated. ResultsSee fig. 3.

As can be seen from FIG. 3, TiO was added with the catalyst 20min before the start of the reaction₂The decolorization rate is obviously increased by increasing the concentration. In TiO₂The dosage is 0.1g/L, and the maximum decolorization rate is 90.4% under the condition of degradation for 80 min. But increase TiO in one taste₂The amount used did not give a better decolorization effect because of the catalyst TiO₂The higher the concentration, the more easily the solution is turbid, and the transmittance of ultraviolet light is affected. Therefore, 0.1g/L of TiO is selected as the best TiO₂And (4) using the amount.

1.3 Effect of initial pH of solution

The pH of the phosphate buffer is adjusted by concentrated NaOH, and the pH is respectively 6, 7, 8, 9 and 10. The adjusted 85mL phosphate buffer and 5mL mother liquor were stirred well and sampled to determine the initial absorbance. Adding 0.1g/L NaCl and 0.1g/L TiO₂Applying voltage 2V, degrading under ultraviolet light for 80min, sampling every 5min before 20min, and sampling every 20min after 20 min. 8mL of the sample is taken each time, the sample is centrifuged at 3200r/min, the supernatant is taken to measure the absorbance, and the decolorization rate is calculated. The results are shown in FIG. 4.

As can be seen from FIG. 4, the decolorization rate of the alkaline black dye wastewater is the greatest when the pH value is 9 and 10 when the photoelectric degradation is carried out for 40 min. This is due to the fact that OH readily passes through OH in aqueous samples in the high pH region^-Direct migration to TiO₂The surface promotes the generation of cavities, so that the corresponding decolorization rate is high. The optimum pH value of 9 was selected in consideration of the fact that too high a pH of the solution would cause a failure in the post-treatment of wastewater.

1.4 influence of applied Voltage

The pH value of the phosphate buffer solution is adjusted to 9 by concentrated NaOH, the adjusted 85mL of phosphate buffer solution and 5mL of mother liquor are stirred uniformly, and sampling is carried out to measure the initial absorbance. Adding 0.1g/L NaCl and 0.1g/L TiO₂And degrading for 1h under ultraviolet light at different voltages, sampling every 5min for the first 20min, and sampling every 20min after 20 min. 8mL of the sample is taken each time, the sample is centrifuged at 3200r/min, the supernatant is taken to measure the absorbance, and the decolorization rate is calculated. The results are shown in FIG. 5.

As can be seen from FIG. 5, the bleaching ratio of the dye did not increase greatly with increasing voltage, but the time to reach the maximum bleaching ratio was greatly shortened, and 12V was selected as the optimum voltage.

1.5 Effect of the amount of NaCl electrolyte added

The pH value of the phosphate buffer solution is adjusted to 9 by concentrated NaOH, the adjusted 85mL of phosphate buffer solution and 5mL of mother liquor are stirred uniformly, and sampling is carried out to measure the initial absorbance. NaCl dosage is 0.1, 0.3, 0.5, 1.0g/L, adding 0.1g/L TiO₂Applying 12V voltage, degrading for 1h under ultraviolet light, sampling every 5min for the first 20min, and sampling every 20min after 20 min. 8mL of the sample is taken each time, the sample is centrifuged at 3200r/min, the supernatant is taken to measure the absorbance, and the decolorization rate is calculated. The results are shown in FIG. 6.

As can be seen from FIG. 6, when the NaCl concentration in the solution is increased from 0.1g/L to 0.5g/L, the decolorization rate of the solution is sequentially increased, but after the NaCl concentration is greater than 0.5g/L, the decolorization rate of the basic black is not obviously changed, because electrolyte ions and dyes compete for adsorption on the surface of the catalyst in the solution, the catalytic activity of the catalyst is reduced. Therefore, 0.5g/L is selected as the optimum electrolyte concentration.

1.6 Effect of degradation time

The pH value of the phosphate buffer solution is adjusted to 9 by concentrated NaOH, the adjusted 85mL of phosphate buffer solution and 5mL of mother liquor are stirred uniformly, and sampling is carried out to measure the initial absorbance. Adding 0.5g/L NaCl, 0.1g/L LTiO₂Applying 12V voltage, degrading for 2h under ultraviolet light, sampling every 5min for the first 20min, and sampling every 20min after 20 min. 8mL of the sample is taken each time, the sample is centrifuged at 3200r/min, the supernatant is taken to measure the absorbance, and the decolorization rate is calculated. The results are shown in FIG. 7.

As can be seen from figure 7, the change of the decoloring rate tends to be smooth along with the prolonging of the decoloring time, the decoloring rate of the dye wastewater is not obviously increased after 1h, and 20min is selected as the optimal decoloring time from the viewpoint of energy conservation.

1.7 Effect of initial concentration of dye

Adjusting the pH value of the phosphate buffer solution to 9 by using concentrated NaOH, uniformly stirring the adjusted 85mL of phosphate buffer solution and 5mL of mother liquor, sampling and measuring initial absorbance, wherein the initial concentrations of the dyes are respectively 15, 30, 40, 50 and 60 mg/L. Adding 0.5g/L NaCl and 0.1g/L TiO₂Applying 12V voltage, degrading for 1h under ultraviolet light, sampling every 5min for the first 20min, and sampling every 20min after 20 min. Each time takingAnd (4) centrifuging 8mL samples at 3200r/min, taking supernate, measuring absorbance, and calculating the decolorization rate. The results are shown in FIG. 8.

As can be seen from fig. 8, as the initial concentration of the dye increased, the decolorization rate gradually decreased, but the maximum decolorization rate reached was substantially uniform. This is because, at the start of the reaction, the high concentration solution seriously hinders the excitation of valence band electrons by ultraviolet light, and the yield of holes and photo-generated electrons is lowered, which is disadvantageous for the formation of active materials such as. OH, while in the low concentration solution, the alkaline black molecules are separated from each other by a large distance and are dispersed, and there is sufficient space for the reaction to be carried out in contact with the catalyst; the more dye molecules can increase the unit mass load of the catalyst, the dye molecules adsorbed on the surface of the catalyst reach saturation at a certain value, the degradation rate cannot be increased by continuously increasing the concentration, and finally the decolorization rate of the dye is reduced. Therefore, 40mg/L was selected as the optimal dye degradation concentration.

Thus, the initial concentration of alkaline black was 40mg/L, and the NaCl concentration was 0.5g/L, TiO₂The concentration is 0.1g/L, the pH value of the solution is 9, and after 12V of external voltage is applied for 20min under the irradiation of an ultraviolet lamp, the decolorization rate can reach 95.04%.

The results of ultraviolet, fluorescence and infrared analysis experiments show that dye wastewater is degraded by the photoelectric system, and dye molecules can be removed fundamentally. It is preliminarily presumed that the reason for the basic black discoloration is mainly that the photoelectric degradation destroys the unsaturated group of the dye and the heterocyclic conjugated coloring system, and some color-promoting groups such as-N ═ N-, -OCH₃、-NR₂Etc. are oxidized and degraded to generate small molecular compounds and CO₂、H₂O, and the like.

Example 2

A method for directly photodegrading basic scarlet based on FTO conductive glass comprises the following specific steps:

(1) fixing graphite electrode and FTO conductive glass on two sides of plastic square electrolytic tank with transparent adhesive tape, respectively, using FTO conductive glass as anode, graphite electrode as cathode, and Na₂HPO₄-NaH₂PO₄Preparing 100mL of simulated basic dye wastewater by using a buffer solution;

(2) adding electrolyte N into waste wateraCl, and photocatalyst nano TiO₂The square electrolytic cell is placed on a magnetic heating stirrer in a darkroom of the ultraviolet curing device, the positive and negative electrodes of a digital voltage-stabilizing and current-stabilizing power supply are respectively connected with an FTO conductive glass electrode and a graphite electrode, the power supply is started to adjust the voltage, and meanwhile, the power supply of the ultraviolet curing device is started to carry out photoelectric degradation on the wastewater.

2.1 acidity of the Environment

When the initial concentration of the dye was 10mg/L, the NaCl addition was 1g/L, the TiO2 addition was 0.1g/L, the applied voltage was 8V, and the illumination time was 60min, the pH values were 6, 7, 8, 9, 10, and 11, respectively, and the absorbance was measured under otherwise identical conditions, respectively, with the results shown in FIG. 9.

As can be seen from fig. 9, when pH is 7, i.e., neutral, the decolorization rate of the dye wastewater is highest, and in the first 10min, the decolorization rate of the environmental acidity at

pH

11 and 10 is greater than that at pH 7, and after 10min, the environmental acidity at pH 7 rises straight, exceeding 10 and 11, while the decolorization rates of 10 and 11 tend to decrease, so it is determined that the pH of the solution during the treatment process is controlled to be 7.

2.2 concentration of electrolyte NaCl

At pH 7, TiO₂The addition of 0.1g/L, the applied voltage of 8V, the initial concentration of the dye of 10mg/L, and the illumination time of 60min, the electrolyte NaCl addition was controlled to be 0.1, 0.3, 0.5, 0.7, 1.0, 1.2, and 1.5g/L, samples were taken every 5min and centrifuged, and the absorbance was measured to obtain the corresponding decolorization rate, and the experimental results are shown in FIG. 10.

Increasing NaCl increases the conductivity of the solution and increases Cl in the solution^-The decolorization of the dye is accelerated by the active chlorine generated by electrolysis and the hydroxyl radical, so that the optimal NaCl concentration of 1.2g/L is selected.

2.3 TiO₂Catalyst and process for preparing same

Keeping other conditions unchanged, respectively preparing TiO at pH 7, NaCl addition 1.2g/L, voltage 8V, dye initial concentration 10mg/L and illumination time 60min₂The solutions with concentrations of 0.01, 0.03, 0.05, 0.07, 0.10, 0.12, 0.15g/L were sampled every 5min to determine the decolorization ratio, and the experimental results are shown in FIG. 11.

As can be seen from FIG. 11, when titanium dioxide was added in an amount ofThe maximum degradation rate and the fastest degradation speed are achieved when the concentration is 0.10g/L, so that the TiO₂The addition amount is comprehensively selected to be 0.1 g/L.

2.4 initial concentration of dye

TiO at pH 7 and NaCl concentration 1g/L₂The addition amount is 0.1g/L, the voltage is applied to 8V, the initial concentration of the prepared dye is 7, 10, 13, 15 and 20mg/L, the dye is respectively subjected to photoelectric decolorization and degradation, samples are taken after every 5min and centrifuged, and the decolorization rate is respectively measured, and the result is shown in figure 12.

As can be seen from the figure, the decolorization rate of the initial concentration of the dye is 10, 7, 13, 15 and 20mg/L from small to large, and obviously, the decolorization rate is the maximum when the initial concentration of the dye is 10mg/L and the time spent when the decolorization rate reaches a flat state is the minimum, so the optimal initial concentration of the dye is 10 mg/L.

2.5 degradation Voltage

At pH 7, NaCl was added in an amount of 1.2g/L, TiO₂When the amount of the dye was 0.1g/L and the initial concentration of the dye was 10mg/L, the applied voltage was controlled to 6, 7, 8, 9 and 10V, and the samples were centrifuged at 5min intervals to measure the absorbance, and the results are shown in FIG. 13.

It can be seen from fig. 13 that, starting from 6V, the decoloring rate increases with increasing voltage, and when the voltage is 8V, the decoloring rate is the highest, the time taken for the degradation to be gradual is the least, and the decoloring rate is the fastest, but starting from 8V, the decoloring rate decreases with increasing voltage. This may be because the number of photo-generated electrons is constant when the intensity of light is fixed, and therefore when the applied voltage reaches a constant value, the photo-generated carriers are sufficiently separated to form a saturated photocurrent. At the moment, the voltage is increased, so that the degradation rate cannot be improved, but the side reaction of anodic oxygen evolution and cathodic hydrogen evolution is aggravated, a large number of bubbles are generated, and the reaction rate of photoelectric degradation is influenced, so that the optimal degradation applied voltage is 8V.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.

Claims

1. A method for directly and photoelectrically degrading basic dye based on FTO conductive glass is characterized by comprising the following steps: the method specifically comprises the following steps:

(1) fixing a graphite electrode and FTO conductive glass on two sides of a plastic square electrolytic cell by using transparent adhesive tapes respectively, taking the FTO conductive glass as an anode and the graphite electrode as a cathode, and preparing 100mL of simulated alkaline dye wastewater by using a buffer solution;

(2) adding electrolyte NaCl and photocatalyst nano TiO into waste water₂The square electrolytic cell is placed on a magnetic heating stirrer in a darkroom of the ultraviolet curing device, the positive electrode and the negative electrode of a digital voltage-stabilizing and current-stabilizing power supply are respectively connected with an FTO conductive glass electrode and a graphite electrode, the power supply is started to adjust the voltage, and meanwhile, the power supply of the ultraviolet curing device is started to carry out a photoelectric degradation experiment.

2. An FTO conductive glass-based method for direct photoelectric degradation of basic dyes according to claim 1, wherein: the basic dye comprises basic scarlet or basic black.

3. An FTO conductive glass-based method for direct photoelectric degradation of basic dyes according to claim 1, wherein: when the basic dye is basic scarlet, the pH value is 7 in the environment, the adding amount of NaCl is 1g/L, and the catalyst TiO₂The adding amount is 0.1g/L, the applied voltage is 8V, the photoelectric decolorization is carried out on the basic scarlet with the initial concentration of 10mg/L for 60min, and the decolorization rate can reach 97.70%.

4. An FTO conductive glass-based method for direct photoelectric degradation of basic dyes according to claim 1, wherein: when the basic dye is basic black, TiO₂When the dosage is 0.1g/L, NaCl and the concentration is 0.5g/L, an external voltage of 12V is applied to the alkaline black solution with the initial concentration of 15mg/L and the pH value of 9, the degradation time is 1h under the ultraviolet light, and the decolorization rate reaches 95.04%.