阅读说明：本技术 一种活化过硫酸盐的氮掺杂石墨烯负载氮化碳复合材料的制备方法及其应用 (Preparation method and application of persulfate-activated nitrogen-doped graphene loaded carbon nitride composite material ) 是由 刘辉 孙萍 翟志才 方应森 于 2020-03-05 设计创作，主要内容包括：本发明提供一种活化过硫酸盐的氮掺杂石墨烯负载氮化碳复合材料的制备方法及其应用,其制备方法,包括以下步骤：S1、原料,选取商用石墨烯、三聚氰胺、尿素；S2、混合,将商用石墨烯、三聚氰胺、尿素均匀混合；S3、煅烧,将S2步骤混合均匀的商用石墨烯、三聚氰胺、尿素在氮气氛围下置于管式炉中,温度控制在500-600℃进行煅烧,且升温速率控制在3-8℃/min,恒温220-250min,在氮气氛围下冷却至室温,便得到了活化过硫酸盐的氮掺杂石墨烯负载氮化碳复合材料g-C<Sub>3</Sub>N<Sub>4</Sub>/rGO-N,该g-C<Sub>3</Sub>N<Sub>4</Sub>/rGO-N对内分泌干扰物BPA、抗生素CIP等新型污染物及常规染料AO7和OG的去除具有高效作用,并且新型氧化系统催化剂和氧化剂的投加量较少,成本比较低。(The invention provides a nitrogen-doped graphene loaded carbon nitride composite material for activating persulfateThe preparation method of the material and the application thereof comprises the following steps: s1, selecting commercial graphene, melamine and urea as raw materials; s2, mixing, namely uniformly mixing the commercial graphene, the melamine and the urea; s3, calcining, namely placing the commercial graphene, melamine and urea which are uniformly mixed in the step S2 in a tube furnace under the nitrogen atmosphere, calcining at the temperature of 500-600 ℃, controlling the heating rate at 3-8 ℃/min, keeping the temperature at 220-250min, and cooling to room temperature under the nitrogen atmosphere to obtain the nitrogen-doped graphene loaded carbon nitride composite material g-C for activating persulfate 3 N 4 /rGO-N, the g-C 3 N 4 the/rGO-N has high-efficiency effect on removing novel pollutants such as endocrine disruptors BPA, antibiotics CIP and the like and conventional dyes AO7 and OG, and the novel oxidation system has less catalyst and oxidant dosage and lower cost.)

1. A preparation method of a nitrogen-doped graphene loaded carbon nitride composite material with persulfate activated is characterized by comprising the following steps:

s1, selecting commercial graphene, melamine and urea as raw materials;

s2, mixing, namely uniformly mixing the commercial graphene, the melamine and the urea;

and S3, calcining, namely placing the commercial graphene, melamine and urea which are uniformly mixed in the step S2 in a tube furnace under the nitrogen atmosphere, calcining at the temperature of 500-600 ℃, keeping the temperature rise rate at 3-8 ℃/min, keeping the temperature at 220-250min, and cooling to room temperature under the nitrogen atmosphere to obtain the nitrogen-doped graphene loaded carbon nitride composite material for activating persulfate.

2. The preparation method of the persulfate-activated nitrogen-doped graphene-supported carbon nitride composite material according to claim 1, wherein the mass ratio of the commercial graphene, the melamine and the urea in the step S1 is (1: 1: 1).

3. The method for preparing the persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material according to claim 2, wherein the commercial graphene is prepared by a reduction-oxidation method, SSA>400m²/g。

4. The preparation method of the persulfate-activated nitrogen-doped graphene-supported carbon nitride composite material according to claim 3, wherein the temperature in the S3 step is controlled at 500 ℃, 550 ℃ and 600 ℃.

5. The preparation method of the persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material according to claim 4, wherein in the step S3, the temperature rise rate is controlled at 5 ℃/min, and the temperature is kept constant for 240 min.

6. Use of persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material in removal of pollutants in water, characterized in that the nitrogen-doped graphene-loaded carbon nitride composite material is prepared by the method for preparing persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material according to any one of claims 1 to 5.

7. Use of persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material in removal of one or more combined pollutants of endocrine disruptors BPA, antibiotics CIP, dyes AO7 and dyes OG in water, characterized in that the nitrogen-doped graphene-loaded carbon nitride composite material is prepared by the persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material preparation method according to any one of claims 1 to 5.

8. The application method of the persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material in removing pollutants in water is characterized by comprising the following steps of taking a certain amount of the nitrogen-doped graphene-loaded carbon nitride composite material prepared by the persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material preparation method according to any one of claims 1 to 6 as a catalyst, adding the catalyst into the sewage to be treated, adding PMS (poly-ammonium-sulfonate) serving as an oxidant, and stirring or oscillating or standing at normal temperature.

9. The application method of the persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material in removing pollutants in water according to claim 8, wherein the sewage to be treated contains AO7 and/or OG, and the mass ratio of the nitrogen-doped graphene-loaded carbon nitride composite material to PMS is 20: 307.

10. the application method of the persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material in removing pollutants in water according to claim 8, wherein the sewage to be treated is a sewage containing endocrine disruptors BPA and/or antibiotics CIP, and the mass ratio of the nitrogen-doped graphene-loaded carbon nitride composite material to PMS is 30: 307.

Technical Field

The invention relates to a preparation method of a nitrogen-doped graphene loaded carbon nitride composite material and an application of the nitrogen-doped graphene loaded carbon nitride composite material in a persulfate-based advanced oxidation water treatment technology, and belongs to the technical field of water pollution control.

Background

Advanced oxidation technologies such as fenton, fenton-like, and photocatalytic technologies have been an effective method for degrading organic pollutants over the last several decades. Compared to these AOPs based on hydroxyl radicals (. OH), the activated Persulfate (PS) technology has been developed in recent years as a sulfate radical (SO)₄ ^·-) Novel AOPs that degrade contaminants for the main active species. It has a higher redox potential, it enables the rapid decomposition of most organic pollutants that are difficult to biodegrade, and the ultimate mineralization of CO₂、H₂O and inorganic salts, and therefore, the activated persulfate technology has become a focus of research in the field of pollution control in recent years. However, at room temperature, PS is very stable and thus has low activity, and O-O bonds should be cleaved to generate highly active species (e.g., SO)₄ ^·-OH or¹O₂Etc.) require energy or chemical activators to the persulfate anion. Common energy sources mainly comprise ultraviolet light, heating, wave radiation, ultrasound, ionizing radiation and the like, and chemical activators mainly comprise transition metal ions, metal oxides, alkali and the like, but the activation modes have the defects of metal ion flow, high energy consumption and the like. Therefore, the development of new metal loss rate is low or even no metal loss is causedAnd catalysts that do not consume other energy sources are the focus of current research.

In recent years, metal-free catalysts have received much attention. Carbon nanomaterials, such as Carbon Nanotubes (CNTs), graphene, have the characteristics of surface chemical inertness, good electrical conductivity, large specific surface area and pore volume, and the like, and have been shown to have a better catalytic effect in various degradation processes. The introduction of carbon nanomaterials into environmental catalysis, as a metal-free heterogeneous catalyst, for the removal of organic contaminants from water would be very promising. Doping carbon nanomaterials with heteroatoms such as nitrogen, sulfur, phosphorus, boron and the like is an effective means for enhancing the catalytic activity of the carbon nanomaterials, and has become a hot spot of research in recent years.

In recent years, a new type of visible light responsive semiconductor photocatalyst graphite phase carbon nitride (g-C)₃N₄) Arouse more and more attention of scholars. g-C in comparison with other semiconductor catalysts₃N₄The preparation method is nontoxic and cheap, can be directly synthesized by thermal shrinkage of nitrogen-rich precursors such as melamine, dicyandiamide and the like, and is easy to obtain. However, the method takes a long time to treat the organic wastewater independently, needs to consume other additional energy sources, and has no ideal effect on the degradation of the organic matters. To solve this problem, researchers have mixed g-C with other oxidants₃N₄The combination enhances the degradation efficiency of the organic matters. For example, there is a large amount of g-C₃N₄Reports of synergistic persulfate degradation of pollutants under visible light, but most of the reports are g-C₃N₄As a research of the photocatalyst, when the photocatalyst is coupled with persulfate, an additional light source is also needed. There have also been some studies of persulfate activators, but these catalysts are mostly metals with g-C₃N₄Of a non-metallic g-C₃N₄Composite materials are less studied.

In view of g-C₃N₄With higher N content and rich graphite nitrogen, we tried to get g-C₃N₄Loaded on a graphene material to prepare a non-metal catalyst capable of efficiently catalytically decomposing PMS degradation pollutants under the condition of no illumination. The research result can provide a new idea and reference for the application of the simple and cheap carbon nitride-loaded catalyst in catalyzing persulfate to degrade pollutants in environmental remediation.

Disclosure of Invention

Technical problem to be solved

The problem to be solved by the invention is to mix g-C₃N₄The non-metal catalyst which can efficiently catalyze and decompose PMS degradation pollutants under the condition of no illumination is prepared by being loaded on a graphene material, and the rGO, melamine and urea are synchronously pyrolyzed and thermally condensed by adopting a one-step method to obtain a novel PMS catalyst g-C₃N₄/rGO-N。

(II) technical scheme

One purpose of the invention is to provide a preparation method of a nitrogen-doped graphene loaded carbon nitride composite material for activating persulfate, which comprises the following steps:

s1, selecting commercial graphene, melamine and urea as raw materials;

s2, mixing, namely uniformly mixing the commercial graphene, the melamine and the urea;

and S3, calcining, namely placing the commercial graphene, melamine and urea which are uniformly mixed in the step S2 in a tube furnace under the nitrogen atmosphere, calcining at the temperature of 500-600 ℃, keeping the temperature rise rate at 3-8 ℃/min, keeping the temperature at 220-250min, and cooling to room temperature under the nitrogen atmosphere to obtain the nitrogen-doped graphene loaded carbon nitride composite material for activating persulfate.

In one aspect, the mass ratio of the commercial graphene, melamine and urea in step S1 is (1: 1: 1)

In one aspect, the commercial graphene is prepared for a reduction oxidation process with SSA >400m 2/g.

In one aspect, the temperature in step S3 is controlled at 500 deg.C, 550 deg.C, 600 deg.C.

In one aspect, the temperature rise rate in step S3 is controlled at 5 deg.C/min, and the temperature is kept constant for 240 min.

Another object of the present invention is to provide a nitrogen-doped graphene-supported carbon nitride composite material for activating persulfate, and an application thereof in removing pollutants in water.

In one aspect, the persulfate-activated nitrogen-doped graphene-loaded carbon nitride composite material is applied to removal of one or more combined pollutants of endocrine disruptors BPA, antibiotics CIP, dyes AO7 and dyes OG in water.

The invention also aims to provide an application method of the nitrogen-doped graphene-loaded carbon nitride composite material for activating persulfate in removing pollutants in water, which comprises the following steps of taking a certain amount of the nitrogen-doped graphene-loaded carbon nitride composite material as a catalyst, adding the catalyst into sewage to be treated, adding PMS (polyethylene glycol styrene) serving as an oxidant, and stirring or oscillating or standing for 30min at normal temperature.

Wherein the sewage to be treated contains dye AO7 and/or dye OG, and the mass ratio of the nitrogen-doped graphene loaded carbon nitride composite material to PMS is 20: 307. and the sewage to be treated contains endocrine disruptors BPA and/or antibiotics CIP, and the mass ratio of the nitrogen-doped graphene loaded carbon nitride composite material to PMS is 30: 307.

(III) advantageous effects

Firstly, compared with other catalysts, the catalyst prepared by the preparation method of the nitrogen-doped graphene loaded carbon nitride composite material for activating persulfate provided by the invention is nontoxic and cheap, can be directly synthesized by thermally shrinking nitrogen-rich precursors such as melamine and dicyandiamide, and is easy to obtain;

secondly, the raw material for preparing the nitrogen-doped graphene-loaded carbon nitride composite material for activating persulfate provided by the invention adopts graphene, has the characteristics of surface chemical inertness, good conductivity, large specific surface area, pore volume and the like, and has a good catalytic effect in various degradation processes, so that the carbon nanomaterial is introduced into environment catalysis to be used as a metal-free heterogeneous catalyst, organic pollutants in water can be effectively removed, and meanwhile, the carbon nanomaterial is environment-friendly and has no secondary pollution such as metal leaching;

finally, the catalyst prepared by the preparation method of the nitrogen-doped graphene loaded carbon nitride composite material for activating persulfate provided by the invention has an efficient effect on removing novel pollutants such as endocrine disruptors BPA, antibiotics CIP and the like and conventional dyes AO7 and OG, and the novel oxidation system has less catalyst and oxidant addition amount and lower cost.

Drawings

Fig. 1 is an XRD diffraction spectrum of the prepared nitrogen-doped graphene-supported carbon nitride composite material.

Fig. 2 is a raman spectrum of the prepared nitrogen-doped graphene-supported carbon nitride composite material.

Fig. 3 is SEM and TEM images of the prepared nitrogen-doped graphene-supported carbon nitride composite material.

Fig. 4 is a BET diagram of the prepared nitrogen-doped graphene-supported carbon nitride composite material.

Fig. 5 is an XPS diagram of the prepared nitrogen-doped graphene-supported carbon nitride composite material.

Fig. 6 is a graph of the removal effect of the prepared nitrogen-doped graphene-loaded carbon nitride composite material on the dye AO 7.

Fig. 7 is a graph showing the effect of the prepared nitrogen-doped graphene loaded carbon nitride composite material on OG, CIP and BPA removal.

Detailed Description

The following examples are given to further illustrate the embodiments of the present invention. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The preparation method of the nitrogen-doped graphene loaded carbon nitride composite material for activating persulfate comprises the following steps: s1, selecting commercial graphene, melamine and urea as raw materials; s2, mixing, namely uniformly mixing the commercial graphene, the melamine and the urea; s3, calcining, namely placing the commercial graphene, melamine and urea which are uniformly mixed in the step S2 in a tube furnace under the nitrogen atmosphere, calcining at the temperature of 500-600 ℃, controlling the heating rate at 3-8 ℃/min, keeping the temperature at 220-250min, and cooling to room temperature under the nitrogen atmosphere to obtain the nitrogen-doped graphene loaded carbon nitride composite material g-C for activating persulfate₃N₄/rGO-N. Wherein g-C₃N₄the/rGO-N is non-toxic,The preparation method is cheap, can be directly synthesized by thermally shrinking nitrogen-rich precursors such as melamine, dicyandiamide and the like, and is easy to obtain.

In step S1, the mass ratio of the commercial graphene, melamine, and urea is (1: 1: 1).

Whereas commercial graphene is prepared by a reduction-oxidation method, SSA>400m²(ii) in terms of/g. The temperature in the step S3 is controlled to 500 deg.C, 550 deg.C, 600 deg.C, preferably 550 deg.C. In the step S3, the temperature rising rate is controlled at 5 ℃/min, and the temperature is kept for 240 min.