阅读说明：本技术 一种蜂窝状纳米氮化碳的制备方法及蜂窝状纳米氮化碳的应用 (Preparation method of cellular nano carbon nitride and application of cellular nano carbon nitride ) 是由 汪斌 洪亮 翁居轼 姚鹏飞 贡洁 陈舟 蔡亚 于 2020-07-21 设计创作，主要内容包括：本发明涉及一种蜂窝状纳米氮化碳的制备方法及蜂窝状纳米氮化碳的应用,包括如下步骤：将尿素置于加盖坩埚中在马弗炉中程序升温进行第一次煅烧,冷却后研磨,再次置于加盖坩埚中在马弗炉中程序升温进行第二次煅烧,冷却后即得蜂窝状的纳米氮化碳；所述第一次煅烧的程序升温速率为10℃/min～20℃/min；所述第一次煅烧的温度为500℃～600℃、保温时间为1h～6h；所述第二次煅烧的程序升温速率为10℃/min～15℃/min；所述第二次煅烧的温度为490℃～560℃、保温时间为1h～10h。本发明方法制得的蜂窝状纳米氮化碳具有较大的比表面积和孔容,对铅离子具有较高的吸附量和去除率。(The invention relates to a preparation method of honeycomb-shaped nanometer carbon nitride and application of the honeycomb-shaped nanometer carbon nitride, which comprises the following steps: placing urea in a covered crucible, carrying out programmed heating in a muffle furnace for primary calcination, grinding after cooling, placing the urea in the covered crucible again, carrying out programmed heating in the muffle furnace for secondary calcination, and obtaining the honeycomb-shaped nano carbon nitride after cooling; the programmed heating rate of the first calcination is 10-20 ℃/min; the temperature of the first calcination is 500-600 ℃, and the heat preservation time is 1-6 h; the temperature programming rate of the second calcination is 10-15 ℃/min; the temperature of the second calcination is 490-560 ℃, and the heat preservation time is 1-10 h. The honeycomb-shaped nanometer carbon nitride prepared by the method has larger specific surface area and pore volume, and has higher adsorption capacity and removal rate for lead ions.)

1. A preparation method of honeycomb-shaped nanometer carbon nitride is characterized by comprising the following steps:

placing urea in a covered crucible, carrying out programmed heating in a muffle furnace for primary calcination, grinding after cooling, placing the urea in the covered crucible again, carrying out programmed heating in the muffle furnace for secondary calcination, and obtaining the honeycomb-shaped nano carbon nitride after cooling;

the programmed heating rate of the first calcination is 10-20 ℃/min; the temperature of the first calcination is 500-600 ℃, and the heat preservation time is 1-6 h;

the temperature programming rate of the second calcination is 10-15 ℃/min; the temperature of the second calcination is 490-560 ℃, and the heat preservation time is 1-10 h.

2. The method for preparing honeycomb nano carbon nitride according to claim 1, wherein the temperature programming rate of the first calcination is 10 ℃/min; the temperature of the first calcination is 550 ℃, and the heat preservation time is 3 h.

3. The method for preparing honeycomb nano carbon nitride according to claim 1, wherein the temperature programming rate of the second calcination is 10 ℃/min; the temperature of the second calcination is 520 ℃, and the heat preservation time is 4 h.

4. The honeycomb-shaped nano carbon nitride prepared by the preparation method according to any one of claims 1 to 3 is applied to adsorption of lead ions in water environment.

5. The application according to claim 4, characterized in that the conditions of the application are: the temperature is 30 ℃, the pH value of the water environment containing lead ions is adjusted to be 3, and 0.4g/L of the honeycomb-shaped nano carbon nitride is added to adsorb the lead ions in the water environment for 1.5 h.

Technical Field

The invention relates to the technical field of nano materials, in particular to a preparation method of honeycomb-shaped nano carbon nitride and application of the honeycomb-shaped nano carbon nitride.

Background

Heavy metal pollution can cause plant withering, air pollution and death of organisms in water, and if the heavy metal pollution enters a human body, the heavy metal pollution can cause damage to the human body and can cause death in serious cases. Heavy metal pollution in wastewater is widely concerned by scholars at home and abroad due to the characteristics of bioaccumulation, high toxicity, easy carcinogenesis and the like. Heavy metal ions such as copper, lead, chromium and the like are typical heavy metal pollutants in wastewater. At present, several technologies are used for treating heavy metals in wastewater, such as neutralization method, ion exchange method, sulfuration method, etc., however, the above methods all have disadvantages, such as the ion exchange method has a great limitation in its application due to its expensive resin cost and regeneration cost; the membrane separation method has high treatment efficiency, but has high cost and complex operation; the chemical precipitation method is accompanied with the generation of a large amount of sludge in the treatment process. The adsorption method can be used for treating various kinds of wastewater containing heavy metals, and particularly has higher treatment efficiency for low-concentration wastewater containing heavy metals.

The graphite phase carbon nitride material has good chemical stability, good biocompatibility and high hardness, and the material has the characteristics of small average pore diameter, more concentrated pore channel structure, high porosity and narrow pore diameter distribution, has the characteristics of short distance, namely disordered atomic level, and long distance, namely ordered mesoscopic level in the structure, and shows good potential in the aspect of adsorbing heavy metal ions in water. However, the common graphite phase carbon nitride is limited by the specific surface area and the pore volume, so that the carbon nitride has a small adsorption amount when being used as a heavy metal ion adsorbent, and too small pore volume can only contain less metal ions, thereby greatly limiting the adsorption capacity of the carbon nitride. So that the modification treatment is particularly important.

Disclosure of Invention

In order to solve the problem of small lead ion adsorption capacity caused by the technical problem of small specific surface area and pore volume of common graphite-phase carbon nitride in the prior art, a preparation method of honeycomb-shaped nano carbon nitride and application of the honeycomb-shaped nano carbon nitride are provided. The structure of the nano carbon nitride prepared by the method is honeycomb-shaped, and has larger specific surface area and pore volume, and the honeycomb-shaped nano carbon nitride has higher adsorption capacity and removal rate to lead ions in water environment.

The invention provides a preparation method of honeycomb-shaped nanometer carbon nitride, which comprises the following steps: and (3) placing the urea in a covered crucible, carrying out programmed heating in a muffle furnace for primary calcination, grinding after cooling, placing in the covered crucible again, carrying out programmed heating in the muffle furnace for secondary calcination, and cooling to obtain the honeycomb-shaped nano carbon nitride. The use of a covered crucible during the calcination process is to make the N element released by the urea under high temperature conditions remain in the product to obtain carbon nitride; the second calcination after grinding is performed in order to uniformly heat the product during the second calcination.

Further, the temperature programming rate of the first calcination is 10-20 ℃/min; the temperature of the first calcination is 500-600 ℃, and the heat preservation time is 1-6 h.

Preferably, the temperature programming rate of the first calcination is 10 ℃/min; the temperature of the first calcination is 550 ℃, and the heat preservation time is 3 h.

Further, the temperature programming rate of the second calcination is 10-15 ℃/min; the temperature of the second calcination is 490-560 ℃, and the heat preservation time is 1-10 h.

Preferably, the temperature programming rate of the second calcination is 10 ℃/min; the temperature of the second calcination is 520 ℃, and the heat preservation time is 4 h.

The invention also provides a method for preparing the honeycomb-shaped nano carbon nitride by using the method.

Further, the conditions of the application are: the temperature is 30 ℃, the pH value of the water environment containing lead ions is adjusted to be 3, and 0.4g/L of the honeycomb-shaped nano carbon nitride is added to adsorb the lead ions in the water environment for 1.5 h.

The beneficial technical effects are as follows:

the invention prepares the cellular nano carbon nitride by secondary calcination, the prepared cellular nano carbon nitride has larger specific surface area and pore volume, the adsorption capacity to lead ions is improved, and the cellular nano carbon nitride prepared by the method has obvious adsorption effect to the lead ions. The invention directly uses cheap urea as raw material, the source of the needed raw material is rich, the preparation process is simple and convenient to operate, the cost is low, and no secondary pollution is caused.

Drawings

Fig. 1 is a scanning electron microscope image of the honeycomb-shaped nano carbon nitride prepared in example 1 of the present invention.

FIG. 2 is a scanning electron microscope photograph of graphite-phase carbon nitride obtained after the first calcination in example 1 of the present invention.

FIG. 3 is the present inventionIllustrating the BET data of the first calcined product graphitic carbon nitride and the second calcined product cellular carbon nitride in comparison of example 1, wherein (a) is a BJH pore size distribution plot, and (b) is N₂Adsorption-desorption isotherm diagram.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention and the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Unless specifically stated otherwise, the numerical values set forth in these examples do not limit the scope of the invention. Techniques, methods known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that the words "first", "second", etc. are used to define the order of calcination, and are only used for convenience of distinguishing the order of the calcination process, and the words have no special meaning unless otherwise stated, and therefore, should not be construed as limiting the scope of the present invention.