A method for preparing photocatalyst using discarded cigarette butts, photocatalyst and application thereof

Abstract

The present invention provides a method for preparing a photocatalyst using waste cigarette butts, a photocatalyst and an application thereof, wherein the method comprises the following steps: collecting used waste cigarette filters containing cigarette tar, pre-treating the waste cigarette filters; carbonizing the waste cigarette filters; and after the waste cigarette filters are carbonized, in situ growing zinc indium sulfur / carbon nitride on the carbonized waste cigarette filters by a hydrothermal method and a thermal polycondensation method to form a zinc indium sulfur / carbon nitride photocatalyst. The present invention improves the hydrogen production efficiency of the photocatalyst to a great extent by carbonizing the waste cigarette filters and in situ growing a heterojunction photocatalytic material on the carbonized waste cigarette filters, thereby achieving not only waste recycling to improve the environment but also clean energy.

Description

Technical Field

[0001] The invention relates to the technical field of photocatalysts, and in particular to a method for preparing a photocatalyst by utilizing discarded cigarette butts, a photocatalyst and an application thereof. Background Art

[0002] Since Fujishima Akira reported the semiconductor-based photocatalytic decomposition hydrogen production system in 1972, photocatalysis has become an ideal method to solve the problems of energy consumption and environmental pollution. Hydrogen is the fuel with the highest energy-to-mass ratio among the currently known fuels, and its combustion products do not cause any pollution. It is the fuel with the greatest potential for future human social and economic development. At the same time, compared with electrical energy, hydrogen energy solves the problem of energy storage. We know that although electricity generated in solar or wind power generation can be directly supplied, when the electricity output is too large, it will cause waste, and hydrogen energy is an ideal energy storage fuel.

[0003] At the same time, in addition to developing clean energy, solving environmental problems also requires solving the pollutants generated in daily life. Although tobacco is harmful to health, it has an astonishing sales volume in most parts of the world, and the proportion of the global population with smoking habits cannot be ignored. Therefore, the solid waste of cigarettes (mainly discarded cigarette filters) generated every day poses a major challenge to the environment. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a photocatalyst using discarded cigarette butts, a photocatalyst and its application in view of the shortcomings of the prior art such as energy consumption and environmental pollution.

[0005] The technical solutions adopted by the present invention to solve the technical problems include the following:

[0006] A method for preparing a photocatalyst using discarded cigarette butts comprises the following steps:

[0007] Collecting used and discarded cigarette filter tips containing tobacco tar, and pre-treating the discarded cigarette filter tips;

[0008] Carbonizing the discarded cigarette filter;

[0009] After the waste cigarette filter tip is carbonized, a hydrothermal method and a thermal polycondensation method are used to in-situ grow zinc indium sulfur / carbon nitride on the carbonized waste cigarette filter tip to form a zinc indium sulfur / carbon nitride photocatalyst.

[0010] Optionally, the specific process of sequentially in-situ growing zinc indium sulfur / carbon nitride on the carbonized waste cigarette filter by a hydrothermal method and a thermal polycondensation method includes:

[0011] In-situ growth of zinc, indium and sulfur on carbonized cigarette tips: The carbonized cigarette filter tip is placed in a mixed solution of zinc nitrate hexahydrate and indium chloride tetrahydrate, stirred for a period of time, and then added with citric acid aqueous solution, and then transferred into an oven, kept warm for a period of time, and then transferred to a vacuum drying oven for drying;

[0012] In-situ growth of carbonitride: The sample on which zinc, indium and sulfur have been in-situ grown is placed in a cyanamide aqueous solution and kept warm in a vacuum drying oven until the water is completely evaporated. The sample is then placed in a tubular furnace and heated and kept warm for a period of time to obtain the final product.

[0013] Optionally, the specific process of in-situ growth of zinc indium sulfur / carbon nitride includes:

[0014] In-situ growth of zinc, indium and sulfur on carbonized cigarette tips: The carbonized cigarette filter tip was placed in a mixed solution of 1 mmol zinc nitrate hexahydrate and indium chloride tetrahydrate, stirred at 50 degrees Celsius for 60 minutes, and then 6 mmol citric acid aqueous solution was added, and then transferred into an oven and kept at 160 degrees Celsius for 12 hours, and then transferred to a vacuum drying oven and dried at 60 degrees Celsius;

[0015] In situ growth of carbonitride: The sample on which zinc, indium and sulfur had been in situ grown was placed in a 10 mmol aqueous solution of cyanamide and kept warm at 80 degrees Celsius in a vacuum drying oven until the water was completely evaporated. The sample was then placed in a tubular furnace and heated to 550 degrees Celsius at a heating rate of 3 degrees Celsius per minute and kept warm for 4 hours to obtain the final product.

[0016] Optionally, the pretreatment includes peeling off the cigarette paper wrapped around the cigarette holder, and then drying to remove moisture.

[0017] Optionally, the carbonized waste cigarette filters are pulverized before the in-situ growth of zinc indium sulphide / carbon nitride on the carbonized waste cigarette filters.

[0018] Optionally, the fibers of the carbonized discarded cigarette filter are in the shape of a spiral ladder, and the spiral ladder morphology provides abundant loading sites and an ultra-large specific surface area for the zinc indium sulfur / carbon nitride photocatalyst.

[0019] Optionally, the process for carbonizing the discarded cigarette filter tips includes: peeling off the cigarette paper portion outside the used discarded cigarette butt filter tip, and cleaning the residual tobacco on the cigarette tip, and then performing high-temperature annealing under inert gas conditions, the annealing temperature is higher than 700 degrees Celsius, the heating rate is less than 5 degrees Celsius per minute, and the highest temperature is kept for a period of time.

[0020] Optionally, the insulation time is 1 to 4 hours.

[0021] The embodiment of the present invention also provides a photocatalyst prepared by using the method for preparing a photocatalyst.

[0022] An application of the photocatalyst includes placing the photocatalyst in a neutral or acidic aqueous solution and performing a photocatalytic hydrogen evolution reaction using natural sunlight or simulated sunlight.

[0023] The present invention has significant technical effects due to the adoption of the above technical solution:

[0024] The present invention relates to a novel photocatalyst and its application that takes into account both daily waste recycling and clean energy production. Waste cigarette filters contain tobacco tar, and the tobacco tar attached to the acetate fibers in the waste cigarette filters during the process of filtering smoke is conducive to the formation of an ideal nano-morphology during the carbonization process. The fibers prepared by carbonizing waste cigarette filters are used to improve the photocatalytic hydrogen evolution efficiency of heterojunction photocatalysts, which can achieve effective charge separation and high photocatalytic hydrogen production activity.

[0025] And because the fibers of the carbonized discarded cigarette filters are in the shape of a spiral ladder, the spiral ladder morphology provides abundant loading sites and an ultra-large specific surface area for the zinc indium sulfur / carbon nitride photocatalyst. The results of X-ray photoelectron spectroscopy show that a strong internal electric field is formed between the fibers and zinc indium sulfur / carbon nitride, allowing sufficient driving force to extract photogenerated electrons from the heterojunction photocatalyst. Compared with the control group, gas chromatography monitored an increase of about 37% in H2 release (322.41 μmol·g-1·h-1). The present invention proposes an attempt to promote photocatalytic hydrogen production using discarded cigarette filters, while achieving waste recycling and clean energy generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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 described below are only some embodiments of the present invention. For ordinary technicians in this field, all other embodiments obtained without creative work are within the scope of protection of the present invention.

[0027] Figure 1 This is a schematic diagram of the preparation process of zinc indium sulfur / carbon nitride photocatalyst using carbonized discarded cigarette filters according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of a scanning electron microscope photograph of a zinc indium sulfur / carbon nitride photocatalyst prepared from carbonized discarded cigarette filters according to an embodiment of the present invention.

[0029] Figure 3 Schematic diagram of fluorescence lifetime spectrum curves of the zinc indium sulfur / carbon nitride photocatalyst (Fiber-ZIS / CN) prepared from carbonized discarded cigarette filters according to an embodiment of the present invention and the zinc indium sulfur / carbon nitride photocatalyst prepared by conventional process.

[0030] Figure 4 Schematic diagram of the photocatalytic hydrogen production efficiency of zinc indium sulfur / carbon nitride photocatalyst (Fiber-ZIS / CN) prepared from carbonized waste cigarette filters in an embodiment of the present invention and a series of control groups (a); schematic diagram of the photocatalytic hydrogen production stability of Fiber-ZIS / CN (b). DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with embodiments. The following embodiments are for explanation of the present invention but the present invention is not limited to the following embodiments.

[0032] Example:

[0033] Please refer to Figure 1 The present invention is a schematic diagram of the preparation process of zinc indium sulfur / carbon nitride photocatalyst using carbonized waste cigarette filter tips. The present invention provides a method for preparing a novel nanomaterial using carbonized waste cigarette filter tips, comprising the following steps:

[0034] Step S100, collecting used and discarded cigarette filter tips containing tar, and pre-treating the discarded cigarette filter tips;

[0035] Step S200, carbonizing the discarded cigarette filter;

[0036] Step S300: After the waste cigarette filter tip is carbonized, zinc indium sulfide / carbon nitride is in situ grown on the carbonized waste cigarette filter tip using a hydrothermal method and a thermal polycondensation method to form a zinc indium sulfide / carbon nitride photocatalyst.

[0037] Specifically, step S100 is performed to collect used discarded cigarette filters containing tar and pre-treat the discarded cigarette filters.

[0038] The raw materials used in the present invention are easily available, which can not only recycle waste to improve the environment but also generate clean energy.

[0039] The discarded cigarette filter tip is used by smokers and is used as the sample preparation of the present invention. Unused brand new cigarettes cannot achieve the photocatalytic hydrogen production effect described in the present invention, because the acetate fiber in the discarded cigarette tip is attached with tobacco tar during the process of filtering smoke, and tobacco tar is conducive to the formation of an ideal nano-morphology in the subsequent carbonization process.

[0040] After collecting enough used discarded cigarette filter tips, the discarded cigarette filter tips are pre-processed, specifically including: peeling off the cigarette paper wrapped outside the discarded cigarette filter tips, and then drying to remove moisture.

[0041] Execute step S200 to carbonize the discarded cigarette filter.

[0042] The dried waste cigarette filter tips are carbonized, and the carbonization process is specifically as follows: peeling off the cigarette paper portion outside the used waste cigarette butt filter tip, and cleaning the residual tobacco on the cigarette tip, and then performing high-temperature annealing in the presence of some inert gases including nitrogen, argon, etc., the annealing temperature is higher than 700 degrees Celsius, the heating rate is less than 5 degrees Celsius per minute, and the temperature is kept at the highest temperature for 1 to 4 hours. The holding time of this process will affect the specific surface area of ​​the final product, and then the annealed carbonized waste cigarette filter tips are crushed to form black powder.

[0043] Step S300 is performed. After the waste cigarette filter tip is carbonized, zinc indium sulfur / carbon nitride is in situ grown on the carbonized waste cigarette filter tip using a hydrothermal method and a thermal polycondensation method to form a zinc indium sulfur / carbon nitride photocatalyst.

[0044] In the embodiment of the present invention, the specific processes of in-situ growth of zinc indium sulfur / carbon nitride on carbonized discarded cigarette filter tips by hydrothermal method and thermal polycondensation method respectively include: in-situ growth of zinc indium sulfur on carbonized cigarette tips: the carbonized cigarette filter tip is placed in a mixed solution of 1mmol zinc nitrate hexahydrate and indium chloride tetrahydrate, stirred at 50 degrees Celsius for 60 minutes, and then 6mmol citric acid aqueous solution is added, and then transferred into an oven and kept warm at 160 degrees Celsius for 12 hours, and then transferred to a vacuum drying oven and dried at 60 degrees Celsius; in-situ growth of carbonized nitrogen: the sample on which zinc indium sulfur has been in-situ grown is placed in a 10mmol monocyanamide aqueous solution and kept warm at 80 degrees Celsius in a vacuum drying oven until the water is completely evaporated, and then the sample is placed in a tubular furnace and heated to 550 degrees Celsius at a heating rate of 3 degrees Celsius per minute and kept warm for 4 hours to obtain the final product.

[0045] The carbonized waste cigarette filter tip does not have a photocatalytic function, but mainly supports and optimizes the photocatalytic material grown on the carbonized waste cigarette filter tip. In this embodiment, the fibers of the carbonized waste cigarette filter tip are in a spiral ladder shape, and the spiral ladder shape provides abundant loading sites and a large specific surface area for the zinc indium sulfur / carbon nitride photocatalyst.

[0046] In this embodiment, the specific method of in-situ growing zinc indium sulfur / carbon nitride on the carbonized waste cigarette filter by hydrothermal method and thermal polycondensation method to form zinc indium sulfur / carbon nitride photocatalyst includes:

[0047] Please refer to Figure 2 This is a scanning electron microscope photo of the zinc indium sulfur / carbon nitride photocatalyst prepared by carbonizing discarded cigarette filters. Figure 2 It can be seen that the carbonized discarded cigarette butts present a spiral structure with fibers entangled together at the microscopic level ( Figure 2 ac). At higher magnification, it can be seen that there are a lot of wrinkles on the surface of these spiral fibers ( Figure 2 d), which reflects that the carbonized waste cigarette butts have a large specific surface area. Thanks to this, using carbonized waste cigarette butts as a high specific surface area carrier to load photocatalysts can effectively improve their reaction efficiency. At the same time, the high conductivity of carbon fibers prepared from waste cigarette filters can also improve the photocatalytic hydrogen evolution efficiency of heterojunction photocatalysts, forming a strong internal electric field between the fibers and zinc indium sulfur / carbon nitride, allowing sufficient driving force to extract photogenerated electrons from the heterojunction photocatalyst.

[0048] Please refer to Figure 3 This is a fluorescence lifetime spectrum of zinc indium sulfur / carbon nitride photocatalyst (Fiber-ZIS / CN) prepared from carbonized waste cigarette filters and zinc indium sulfur / carbon nitride (ZIS / CN) photocatalyst in the prior art. In the figure, the lifetime of zinc indium sulfur / carbon nitride photocatalyst (Fiber-ZIS / CN) prepared from carbonized waste cigarette filters is obviously higher than that of zinc indium sulfur / carbon nitride (ZIS / CN) photocatalyst in the prior art, especially in the range of 1 to 4 nanoseconds.

[0049] The embodiment of the present invention also provides a zinc indium sulfur / carbon nitride photocatalyst prepared by a method for preparing a photocatalyst using discarded cigarette butts.

[0050] The embodiment of the present invention also provides an application of using the above zinc indium sulfur / carbon nitride photocatalyst to produce hydrogen, specifically comprising: placing the photocatalyst in a neutral or acidic aqueous solution, and using natural sunlight or simulated sunlight to perform a photocatalytic hydrogen evolution reaction.

[0051] Some control group experiments were also conducted in the examples of the present invention to prove that the present invention is indeed of great help in the field of clean energy. Figure 4(a) is a graph of hydrogen production efficiency of zinc indium sulfur / carbon nitride photocatalyst (Fiber-ZIS / CN) supported by carbonized waste cigarette filters and some control groups. The photocatalysts used in the present invention are mainly zinc indium sulfur / carbon nitride (ZIS / CN), zinc indium sulfur / carbon nitride photocatalyst (Fiber-ZIS / CN) supported by carbonized waste cigarette filters, carbon nitride (CN), zinc indium sulfur (ZIS), and zinc indium sulfur (Fiber-ZIS) supported by carbonized waste cigarette filters. It can be seen from the figure that the hydrogen production efficiency of zinc indium sulfur / carbon nitride photocatalyst (Fiber-ZIS / CN) supported by carbonized waste cigarette filters is the highest. Except that the hydrogen production effect of carbon nitride (CN) is not obvious, the hydrogen production efficiency of the other three photocatalysts is similar, and compared with the control group, gas chromatography monitored that H2 release (322.41μmol·g-1·h-1) increased by about 37%. This work proposes an attempt to promote photocatalytic hydrogen production using waste cigarette filters.

[0052] refer to Figure 4 (b) is a graph of the stability of photocatalytic hydrogen production by Fiber-ZIS / CN. It can be seen from the figure that with the increase of the cycle, the photocatalytic hydrogen production ability of Fiber-ZIS / CN is relatively stable and can be roughly maintained at the same level. Therefore, the use of zinc indium sulfur / carbon nitride photocatalyst (Fiber-ZIS / CN) to produce hydrogen in the present invention is of great help in increasing the output of hydrogen energy storage.

[0053] In addition, it should be noted that the above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any equivalent or simple changes made according to the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a photocatalyst using discarded cigarette butts, characterized in that: The steps include: Collecting used and discarded cigarette filter tips containing tobacco tar, and pre-treating the discarded cigarette filter tips; Carbonizing the discarded cigarette filter; After the waste cigarette filter tip is carbonized, a hydrothermal method and a thermal polycondensation method are used to sequentially in-situ grow zinc indium sulfur / carbon nitride on the carbonized waste cigarette filter tip to form a zinc indium sulfur / carbon nitride photocatalyst. The specific process includes: In-situ growth of zinc, indium and sulfur on carbonized cigarette tips: The carbonized cigarette filter tip is placed in a mixed solution of zinc nitrate hexahydrate and indium chloride tetrahydrate, stirred for a period of time, and then added with citric acid aqueous solution, and then transferred into an oven, kept warm for a period of time, and then transferred to a vacuum drying oven for drying; In-situ growth of carbonized nitrogen: the sample on which zinc, indium and sulfur have been in-situ grown is placed in a cyanamide aqueous solution and kept warm in a vacuum drying oven until the water is completely evaporated, and then the sample is placed in a tube furnace and heated and kept warm for a period of time to obtain the final product; The zinc indium sulfur / carbon nitride is loaded on the fiber of the carbonized discarded cigarette filter, and an internal electric field is formed between the fiber of the carbonized discarded cigarette filter and the zinc indium sulfur / carbon nitride.

2. The method for preparing a photocatalyst using discarded cigarette butts according to claim 1, characterized in that: The specific process of in-situ growth of zinc indium sulfur / carbon nitride specifically includes: In-situ growth of zinc, indium and sulfur on carbonized cigarette tips: The carbonized cigarette filter tip was placed in a mixed solution of 1 mmol zinc nitrate hexahydrate and indium chloride tetrahydrate, stirred at 50 degrees Celsius for 60 minutes, and then 6 mmol citric acid aqueous solution was added, and then transferred into an oven and kept at 160 degrees Celsius for 12 hours, and then transferred to a vacuum drying oven and dried at 60 degrees Celsius; In situ growth of carbonitride: The sample on which zinc, indium and sulfur had been in situ grown was placed in a 10 mmol aqueous solution of cyanamide and kept warm at 80 degrees Celsius in a vacuum drying oven until the water was completely evaporated. The sample was then placed in a tubular furnace and heated to 550 degrees Celsius at a heating rate of 3 degrees Celsius per minute and kept warm for 4 hours to obtain the final product.

3. The method for preparing a photocatalyst using discarded cigarette butts according to claim 1, characterized in that: The pretreatment includes stripping off the cigarette paper wrapped around the cigarette filter, and then drying to remove moisture.

4. The method for preparing a photocatalyst using discarded cigarette butts according to claim 1, characterized in that: Prior to in-situ growth of zinc indium sulfide / carbon nitride on the carbonized waste cigarette filters, the carbonized waste cigarette filters are pulverized.

5. The method for preparing a photocatalyst using discarded cigarette butts according to claim 1, characterized in that: The fibers of the carbonized discarded cigarette filter are in a spiral ladder shape, and the spiral ladder shape provides abundant loading sites and an ultra-large specific surface area for the zinc indium sulfur / carbon nitride photocatalyst.

6. The method for preparing a photocatalyst using discarded cigarette butts according to claim 1, characterized in that: The process for carbonizing the discarded cigarette filter includes: high-temperature annealing under inert gas conditions, the annealing temperature is higher than 700 degrees Celsius, the heating rate is less than 5 degrees Celsius per minute, and the temperature is kept at the highest temperature for a period of time.

7. The method for preparing a photocatalyst using discarded cigarette butts according to claim 6, characterized in that: The insulation time is 1 to 4 hours.

8. A photocatalyst prepared by the method for preparing a photocatalyst using discarded cigarette butts as claimed in claim 1.

9. An application of the photocatalyst according to claim 8, characterized in that: The method comprises placing the photocatalyst in a neutral or acidic aqueous solution and using natural sunlight or simulated sunlight to perform a photocatalytic hydrogen evolution reaction.

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