CN110734127A - A carbon composite nano-zero-valent metal porous functional material, its preparation method and application - Google Patents

Abstract

The invention provides a carbon composite nanometer zero-valent metal porous functional material, a preparation method and application thereof. The preparation method of carbon composite nano-zero-valent metal porous functional material includes the following steps: using meteorite powder as raw material to obtain nano-zero-valent metal composite material through reduction and calcination; mixing zeolite, cement, quicklime, aluminum powder, gypsum and surfactant The ingredients are poured, foamed, cut, and cured by autoclave to obtain a composite porous material; the surface of the composite porous material is evenly coated with the nano-zero-valent metal composite material, and after curing in bulk water, it is naturally cured to obtain a composite porous material. Carbon composite nano-zero-valent metal porous functional materials. The material prepared by the invention has multi-level pores, high porosity and large specific surface area, provides space for microorganisms to enter the carbon composite nanometer zero-valent metal porous functional material for attachment and growth, and can be used as artificial wetland matrix or sponge city. Matrix treatment of wastewater, high pollutant removal rate.

Description

A carbon composite nano-zero-valent metal porous functional material, its preparation method and application

technical field

The invention relates to the technical field of composite materials, in particular to a carbon composite nano-zero-valent metal porous functional material, a preparation method and application thereof.

Background technique

Industrial wastewater such as heavy metals is extremely serious to environmental pollution and its harm to human beings. Compared with traditional wastewater treatment technology, constructed wetland systems have been widely used in industrial wastewater treatment due to the advantages of less investment and low operating costs. The constructed wetland system mainly uses the interaction between the filler matrix, aquatic plants and microorganisms in the wetland to purify the sewage through a series of physical, chemical and biological methods. The filler in the system plays an important role in the wetland sewage treatment process. The main site of sewage treatment, which removes pollutants through interception, filtration, adsorption and precipitation.

At present, the filler matrix of constructed wetlands is mainly composed of soil, fine sand, coarse sand, gravel, broken tiles or ash, steel slag and other materials through simple accumulation, but the fillers prepared by this method generally have insufficient mechanical strength and are easy to block. , nitrogen and phosphorus adsorption capacity is low and other shortcomings, and its limited porosity, specific surface area and other properties seriously restrict the purification efficiency of constructed wetlands for sewage.

In addition, with the acceleration of urbanization, problems such as urban waterlogging, water shortage and runoff pollution have become more prominent. According to the EPA, stormwater runoff has been listed as the third largest source of water pollution. Since the release of the "Technical Guidelines for Sponge City Construction" in October 2014, urban runoff reduction and collection, rainwater purification and rational utilization have become the focus of urban construction in my country in the new era and one of the focuses of water environment research. The essence of sponge city construction is to realize the natural accumulation, natural infiltration and natural purification of rainwater through the combination of artificial facilities and natural channels, and to "release" rainwater when water is scarce, forming a good natural cycle and promoting the utilization of rainwater resources and ecological Environmental protection. The occurrence of urban rainwater runoff is random and intermittent, and the pollution sources are widely distributed, not concentrated, and the concentration of pollutants varies greatly. How to effectively collect, purify and store urban runoff rainwater is one of the keys to solving the problem. It is an effective way to solve the problem by making full use of the urban non-hardened underlying surface and maintaining its original life and ecological functions. In recent years, research on reducing surface water pollution and urban rainfall runoff pollution using the principle of soil infiltration has received extensive attention. In the 1970s, foreign countries have begun to use various types of green space to save surface runoff and reduce runoff pollution. Among them, optimizing the filling matrix of the underlying surface of the non-hardened area is an effective way to improve the rainwater treatment performance of the system. At present, the research on the urban underlying surface is only Staying in the traditional sand-soil matrix ratio optimization and layered filling, the space for improving the speed of rainwater infiltration is limited and the reduction of pollutants is difficult to meet the reuse standards.

SUMMARY OF THE INVENTION

The problems solved by the invention are that the existing constructed wetland fillers and sponge city substrates are easy to block, have low adsorption capacity and poor pollutant removal effect.

In order to solve at least one aspect of the above problems, the present invention provides a preparation method of a carbon composite nano-zero-valent metal porous functional material, comprising the following steps:

Step S1, using meteorite powder and biomass powder as raw materials, through reduction and calcination to obtain nano-zero-valent metal composite material;

In step S2, zeolite, cement, quicklime, aluminum powder, gypsum and surfactant are mixed and batched, and the composite porous material is prepared by pouring, foaming, cutting, and autoclave curing;

In step S3, the nano-zero-valent metal composite material is uniformly spread on the surface of the composite porous material, and after being cured by scattered water, the carbon-composite nano-zero-valent metal porous functional material is prepared by natural curing.

Optionally, the nano-zero-valent metal composite material in step S1 is obtained by calcining the meteorite powder and biomass powder in a hydrogen or carbon monoxide atmosphere.

Optionally, in step S1, the calcination is carried out in a hydrogen or carbon monoxide atmosphere, the calcination temperature is 400-900°C, and the calcination time is 2h-5h.

Optionally, the particle sizes of the meteorite powder and the biomass powder in step S1 are both less than 0.0374 mm.

Optionally, the mass ratio of the meteorite powder to the biomass powder is 1-3:1.

Optionally, the conditions of the autoclaved curing in step S2 are 1Mpa-2Mpa, the steam curing is 5h to 8h, and the steam curing temperature is 180°C±5°C.

Optionally, in step S2, the mass percentages of the zeolite, the cement, the quicklime, the aluminum powder, and the gypsum are respectively 50-65%, 20-40%, 3-11%, 0.5-2% %, 1-5%.

Optionally, described in step S3, in the surface of the composite porous material evenly spread the nano zero-valent metal composite material, the weight ratio of the nano zero-valent composite material to the composite porous material is 1-5: 90-100.

The present invention also provides a carbon composite nano-zero-valent metal porous functional material prepared by the preparation method of the carbon composite nano-zero-valent metal porous functional material according to any one of the above.

Optionally, the carbon composite nano-zero-valent metal porous functional material has multi-level pores, including micropores of 1 nm-2 nm, mesopores of 10 nm-50 nm, and macropores of 50 nm-1000 μm.

Optionally, the porosity of the carbon composite nano-zero-valent metal porous functional material is 90%-99%.

Optionally, the specific surface area of the carbon composite nano-zero-valent metal porous functional material is 70-250 m ² /g.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The carbon composite nano-zero-valent metal porous functional material prepared by the present invention has multi-level pores, including micropores, mesopores and macropores, and also has higher porosity and larger specific surface area, and is a microbial It provides space for the growth of the carbon composite nano-zero-valent metal porous functional material inside the attachment.

(2) The carbon composite nano-zero-valent metal porous functional material prepared by the present invention contains nano-zero-valent metal composite material, and the carbon composite nano-zero-valent metal porous functional material can form a multi-metal system. Therefore, compared with the traditional artificial wetland filler, the present invention has strong adsorption capacity and good pollutant removal effect.

(3) In the present invention, biomass is added when preparing the carbon composite nano-zero-valent metal porous functional material, because the biomass will form a pore structure during the calcination process, which increases the specific surface area and porosity of the carbon composite nano-zero-valent metal porous functional material, and further improve its adsorption performance.

(4) The carbon composite nano-zero-valent metal porous functional material prepared by the present invention also includes a zeolite component, and the zeolite has the effect of removing nitrogen, ion exchange and adsorption, and also includes calcium hydroxide, which can fix the phosphate in the wastewater , and generate hydroxyapatite on the surface of the carbon composite nano-zero-valent metal porous functional material to achieve simultaneous recovery of phosphorus and removal of nitrogen.

(5) The preparation process of the present invention is simple, the recycling of waste is realized, resources are saved, and the preparation method is simple and the production cost is low.

The present invention also provides an application of the above-mentioned carbon composite nano-zero-valent metal porous functional material in constructed wetlands.

Using the carbon composite nano-zero-valent metal porous functional material prepared by the invention as a constructed wetland substrate to treat wastewater has high pollutant removal rate and simple treatment process.

Description of drawings

Fig. 1 is the SEM image of the outer surface of carbon composite nano-zero-valent metal porous functional material in the embodiment of the present invention;

FIG. 2 is a SEM image of the inner surface of the carbon composite nano-zero-valent metal porous functional material in the embodiment of the present invention.

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The invention provides a preparation method of a carbon composite nano-zero-valent metal porous functional material, comprising the following steps:

Step S1, using meteorite powder and biomass powder as raw materials, through reduction and calcination to obtain nano-zero-valent metal composite material;

In step S2, zeolite, cement, quicklime, aluminum powder, gypsum and surfactant are mixed and batched, and the composite porous material is prepared by pouring, foaming, cutting, and autoclave curing;

In step S3, the surface of the composite porous material is evenly spread, and the nano-zero-valent metal composite material is cured by scattered water and then naturally cured to obtain a carbon composite nano-zero-valent metal porous functional material.

In the present invention, the meteorite powder and the biomass powder are respectively obtained by pre-processing the meteorite and the biomass, and the meteorite powder and the biomass powder are obtained according to the mass ratio of 1:1-3: 1. After uniform mixing, it is calcined in a reducing atmosphere, and then naturally cooled to room temperature in an oxygen-free atmosphere to obtain a nano-zero-valent metal composite material with high activity. The reducing atmosphere includes hydrogen or carbon monoxide; the calcination temperature of reduction calcination is 400-900° C., and the calcination time is 2-5h.

The present invention generates nano-zero-valent metal composite carbon material by adding biomass to the meteorite powder after calcination, because the biomass will form a pore structure during the calcination process, increase the specific surface area and porosity, and further improve its adsorption performance.

Wherein, the biomass powder is obtained by grinding any material from leaves, corn cob, rice husk, cut tobacco, sawdust, straw, lotus leaf, walnut shell, waste peach core shell or paper mill waste pulp fiber. Sieve to obtain biomass powder with particle size less than 0.0374mm.

The meteorite pretreatment process is as follows: at room temperature, the meteorite is crushed to a particle size of less than 0.0374mm. Under the crushed particle size, the meteorite has a larger specific surface area, and the dangling bonds on the meteorite surface increase accordingly. With the increase of active sites, the catalytic capacity is also improved accordingly. Then, the meteorite with a particle size of less than 0.0374mm is fully mixed and dispersed with alcohol, and then dried to obtain a meteorite powder. The above pretreatment of meteorite can improve the dispersion performance of each active component of meteorite and improve the catalytic activity.

Meteorites are small pieces of solid debris, which originate from asteroids or comets, originate in outer space, and have an impact on the surface of the earth and on life. Known as meteors before they hit the surface, meteorites range in size from small to extremely large. When a meteoroid enters Earth's atmosphere, it heats up and emits light due to friction, pressure, and the chemistry of gases in the atmosphere, thus forming meteors, including fireballs, also known as shooting stars. Fireballs are both alien celestial bodies that collide with Earth and unusually bright meteors, and meteors like fireballs end up affecting Earth's surface anyway. More generally speaking, any meteorite on the surface of the earth is a natural object from outer space. Meteorites have also been found on the Moon and Mars. Meteorites that are observed to pass through the atmosphere or hit the earth are called fall meteorites, and other meteorites are called discovery meteorites. As of February 2010, only about 1,086 specimens of falling meteorites were collected, but there were 38,660 confirmed meteorites found. Meteorites are usually divided into three categories: stony meteorites are mainly rocks, and their composition is mostly silicate minerals; iron meteorites, most of which are composed of iron and nickel; stony-iron meteorites are composed of both a large number of rocks and metals. The modern classification of meteorites is based on their structure, chemical isotopes and mineralogy, with meteorites smaller than 2 mm being classified as micrometeorites. Meteorites in the present invention mainly include ferrugites, cones, stony-iron meteorites or nickel-iron meteorites.

The main components of meteorites are iron, nickel, manganese, arsenic, molybdenum, zirconium, niobium, ruthenium, rhodium, silver, cadmium, indium, cobalt, palladium, tin, antimony and other transition metals. Because meteorites contain a large amount of transition metals, transition metal oxides have the following properties: the d electron layer of metal cations in transition metal oxides is easy to lose electrons or take electrons, and has strong redox properties; transition metal oxides have semiconductor properties. Properties; the inner valence orbital and the extrinsic orbital of metal ions in transition metal oxides can be split; both transition metal oxides and transition metals can be used as redox catalysts, while the former has strong heat resistance and toxicity resistance, and It has photosensitivity, heat sensitivity, impurity sensitivity, and is more conducive to the modulation of catalyst performance, so it is more widely used; transition metals such as Fe and Co can form a strong synergistic effect with Ni metal, and can also significantly improve the catalytic activity of Ni-based catalysts.

The nano-zero-valent metal composite material prepared by using meteorites as raw materials in the present invention mainly includes nano-zero-valent iron, nano-zero-valent nickel, nano-zero-valent copper and nano-rare metals. In the prior art, in the catalytic reaction, a passivation layer, such as iron hydroxide precipitation, is formed on the surface of the zero-valent iron particles, thereby reducing the activity of the nano-iron. The nano-zero-valent metal composite material prepared by the invention contains metals with high reduction potential (such as palladium, copper and nickel), and is a multi-component composite material. In the catalytic reaction, due to the different potential differences of various metals on the surface of the multi-metal particles of the nano-zero-valent metal composite, a galvanic cell is formed between the various metals, which increases the activity of metallic iron in the nano-zero-valent metal composite. , so as to provide more electrons to participate in the catalytic reaction and improve the catalytic degradation efficiency. Therefore, on the one hand, the multi-component composite material can enhance the activity of the metal of the nano-zero-valent metal composite material, and on the other hand, the metals in the nano-zero-valent metal composite material can play a synergistic effect, improving the nano-zero-valent metal composite material. The speed and selectivity with which metals participate in reduction reactions. Therefore, the nano-zero-valent metal composite material prepared in step S1 of the present invention can form a multi-metal system and improve the rate of catalytic reaction.

The present invention uses natural zeolite powder as the framework of the porous functional material, high-strength Portland cement as the binder, aluminum powder as the foaming agent, quicklime to provide alkalinity, gypsum coagulant, washing powder or saponin powder as the surface Active agent, the mass percentages of the zeolite, the cement, the quicklime, the aluminum powder, and the gypsum are 50-65%, 20-40%, 3-11%, 0.5-2%, 1- 5%, through batching, mixing, casting, foaming, dicing, and autoclaving to obtain a composite porous material. The zeolite is natural clinoptilolite, the cement is preferably Portland cement, the content of aluminum powder is 90-99%, the particle size of quicklime is less than 0.037mm, the content of quicklime is 90-99%, and the content of gypsum is 90-99%. After mixing the above-mentioned raw materials in proportion, add water, stir and mix to obtain a mixed slurry, put the mixed slurry into a mold, and place the mold in an incubator for gas generation to obtain a block, wherein the temperature in the incubator is temperature: 60±2℃, gas generation time: 3.0-3.5h, take out the mold from the incubator, and take out the block from the mold, cut the block into cubes with a size of 10±5mm with a brick cutter, and The cubes are placed in an autoclave at 180±5° C. and autoclaved for 5-8 hours to prepare a composite porous material, and the composite porous material has a rich open pore structure.

During the preparation of the composite porous material, the aluminum powder can generate hydrogen in an alkaline solution, and at the same time generate a porous structured material, while the active component quicklime provides alkalinity on the one hand, and provides an alkaline environment for the aluminum powder to produce hydrogen and create pores. On the other hand, its main component, calcium oxide, reacts with water to release a lot of heat, which increases the temperature of the billet. In order to prevent the heat generated by the reaction between calcium oxide and water from oxidizing the nano-zero-valent metal composite material prepared in step S1, in step S3 of the present invention, after cooling the composite porous material, the surface of the prepared composite porous material is evenly coated with nanometer The zero-valent metal composite material is cured to obtain a carbon composite nano-zero-valent metal porous functional material. Wherein, the weight ratio of the nano-zero-valent composite material to the composite porous material is 1-5:90-100, so that the nano-zero-valent metal composite material falls into the internal pores of the open pores of the composite porous material, and then moves toward the composite porous material. The surface of the porous material is evenly sprayed with water, and the composite porous material is naturally cured for 5 to 30 days to obtain a carbon composite nano-zero-valent metal porous functional material.

The carbon composite nanometer zero-valent metal porous functional material prepared by the invention has multi-level pores, including micropores of 1nm-2nm, mesopores of 10nm-50nm and macropores of 50nm-1000μm. At the same time, it also has a high porosity and a large specific surface area, in which the porosity is 90-99% and the specific surface area is 70-250 m ² /g, which is the internal adhesion and growth of microorganisms entering the carbon composite nano zero-valent metal porous functional material. Provide space.

The nano-zero-valent metal porous functional material prepared by the invention not only has the properties of nano-zero-valent metal composite material, but also includes zeolite components, zeolite has the effect of removing nitrogen, ion exchange and adsorption, and also includes calcium hydroxide , which can fix phosphate in wastewater, and generate hydroxyapatite on the surface of carbon composite nano-zero-valent metal porous functional material to achieve simultaneous recovery of phosphorus and removal of nitrogen. In addition, the preparation process of the invention is simple, the recycling of waste is realized, and the production cost is low. Compared with the traditional filler, the present invention has strong adsorption capacity and good pollutant removal effect.

In some of the embodiments, the present invention uses the prepared carbon composite nano-zero-valent metal porous functional material as a constructed wetland matrix or sponge city matrix for water treatment. In this embodiment, the carbon composite nano-zero-valent metal porous functional material is used as a constructed wetland A matrix is used as an example to describe in detail.

Plants (such as aquatic plants or marsh plants, etc.), microorganisms (bacteria, fungi, etc.) and the carbon composite nano-zero-valent metal porous functional material together constitute an interdependent system. Among them, the microorganisms in the constructed wetland system are the main force to degrade the pollutants in the water body. The aerobic microorganisms decompose most of the organic matter in the wastewater into carbon dioxide and water through respiration, and the anaerobic bacteria decompose the organic matter into carbon dioxide and methane. Nitrifying bacteria nitrify ammonium salts, and denitrifying bacteria reduce nitrate nitrogen to nitrogen gas. Through this series of actions, the main organic pollutants in the sewage can be degraded and assimilated to become part of the microbial cells, and the rest will be returned to nature as environmentally harmless inorganic substances. In addition, there are some protozoa and metazoans in the constructed wetland ecosystem. Insects and birds in the constructed wetland system can also participate in swallowing the organic particles deposited in the wetland system, and then assimilate the organic particles as nutrients. , so as to remove the particulate matter in the sewage to some extent.

The carbon composite nano-zero-valent metal porous functional material prepared by the present invention has a high open porosity, so that various microorganisms can be attached to the outer surface and the interior of the carbon composite nano-zero-valent metal porous functional material, and microorganisms can be located in all kinds of microorganisms. The carbon composite nanometer zero-valent metal porous functional material forms a redox zone on the outer surface and inside, and has the functions of oxidizing ammonia nitrogen and denitrifying nitrogen at the same time.

The carbon composite nano-zero-valent metal porous functional material prepared by the invention can be used as an excellent microbial carrier material with biological activity, providing a place for microbial reproduction and growth. At the same time, the carbon composite nano-zero-valent metal porous functional material, as a filler, also has the function of simultaneous denitrification and phosphorus removal in the constructed wetland, and can selectively adsorb ammonia nitrogen in water.

In the constructed wetland system, the plant rhizomes bring oxygen into the carbon composite nano-zero-valent metal porous functional materials dispersed around it, but the environment far from the plant roots is still in an anaerobic state, which forms an environmental change Therefore, the ability of constructed wetlands to remove complex pollutants (refractory organic matter) and nitrogen and phosphorus can be improved. The removal of most organic pollutants and nitrogen and phosphorus compounds in sewage can rely on microorganisms in the mechanism, but some pollutants such as heavy metals, sulfur, phosphorus, etc. can be absorbed by the carbon composite nano-zero-valent metal porous functional materials and plants. reduce its concentration. The carbon composite nano-zero-valent metal porous functional material can, on the one hand, remove ammonia nitrogen in wastewater by ion exchange and adsorption; In order to realize the regeneration of the zeolite in the carbon composite nano-zero-valent metal porous functional material, the iron-oxidizing bacteria and the anaerobic ammonia-oxidizing bacteria that depend on nitrate are loaded. In the constructed wetland system, the ammonia nitrogen adsorbed by the carbon composite nano-zero-valent metal porous functional material is converted into nitrate by aerobic ammonia oxidizing bacteria, and then washed into the sewage by the constructed wetland system. The conversion of nitrifying bacteria into nitrogen is not only beneficial to the removal of total nitrogen, but also the denitrification process consumes the chemical oxygen demand (COD) in the sewage, reducing the COD load of the sewage treatment system. Using a small amount of organic matter in the gap of carbon composite nano-zero-valent metal porous functional materials as a carbon source, while degrading nitrate, relying on nitrate-type iron oxidizing bacteria, it can oxidize ferrous minerals to form ferric hydroxide, while iron The hydroxide has a good adsorption effect on phosphate and can be used to remove phosphate. The adsorption of phosphorus by carbon composite nano-zero-valent metal porous functional materials and the chemical reaction of phosphate ions, the removal mechanism is that Al ³⁺ , Ca ²⁺ , Fe ³⁺ plasma in the matrix can react with PO ₄ ^3- and precipitate by adsorption reaction Removal of PO ₄ ^3- , in which PO ₄ ^3- interacts with Ca ²⁺ under alkaline conditions, and reacts with Al ³⁺ and Fe ³⁺ under neutral or acidic environmental conditions. It is adsorbed on the surface of Al ³⁺ and Fe ³⁺ due to site exchange. In addition, the anaerobic condition formed by the structure of the carbon composite nano-zero-valent metal porous functional material itself makes the denitrification reaction proceed thoroughly, and further improves the removal effect of nitrate nitrogen.

The carbon composite nano-zero-valent metal porous functional material described in the present invention not only has the function of adsorbing ammonia nitrogen in water, but also is an efficient microbial carrier material, which can efficiently remove nitrogen and phosphorus in wastewater, and also has the ability to adsorb various organic pollutants in water. effect. Among them, the nano-iron in the nano-zero-valent metal composite material can be coupled with anaerobic bacteria (such as ammonia oxidizing bacteria), and this component is first reduced to nitrite, and then further reduced to ammonia nitrogen. Anammox bacteria can utilize the system The two substances generated successively undergo biological conversion to achieve biological denitrification. In addition, this component can be coupled with the denitrifying bacteria system to reduce the reaction time and speed up the denitrification reaction rate. And carbon composite nano-zero-valent metal porous functional materials include composite porous materials with porous structure and nano-zero-valent metal composite materials with high activity, and the nano-zero-valent metal composite materials can form a multi-metal system. It can play a synergistic role and improve the catalytic degradation efficiency; in addition, the oxidation of nano-zero-valent Ni to Ni ²⁺ can not only accelerate the electron transfer rate of nano-iron, improve the chemical reaction rate, but also promote the ^degradation of anaerobic microorganisms. grow. The carbon composite nano-zero-valent metal porous functional material can be applied to a constructed wetland matrix, as a carrier material for microorganisms, has the function of simultaneous denitrification and phosphorus removal, and is especially suitable for the treatment of eutrophic wastewater.

Example 1

The preparation method of carbon composite nano-zero-valent metal porous functional material in this embodiment includes the following steps:

The meteorite and straw were crushed and sieved to less than 0.0374mm, the meteorite powder and the leaf powder were mixed according to a mass ratio of 3:1 to obtain a mixed powder, and the mixed powder was calcined in a hydrogen atmosphere, and the calcination temperature was 600 ° C , the time is 3h, the nano zero-valent metal composite material is prepared;

At the same time, the natural zeolite powder, high-strength Portland cement, quicklime, aluminum powder, and gypsum are mixed according to the mass percentage of 50-65%, 20-40%, 3-11%, 0.5-2%, 1-5% respectively. , mixing, casting, foaming, and autoclaving at a high temperature of 180 ° C for 6 hours to obtain a composite porous material;

Finally, the surface of the composite porous material was evenly sprinkled with the nano-zero-valent metal composite material, the weight ratio of the nano-zero-valent composite material and the composite porous material was 5:90, and the carbon composite nano-zero-valent metal porous function was obtained by watering and curing for 10 days. Material.

The performance test of the carbon composite nano zero-valent metal porous functional material prepared in this example is carried out. The results are shown in Table 1. It can be seen from Table 1 that the pores of the carbon composite nano zero-valent metal porous functional material prepared in this example are The rate is 64%-98%, the specific surface area is 123-250m ² /g, and the compressive strength is 79-94N.

Table 1:

SEM tests were performed on the inner and outer surfaces of the carbon composite nano-zero-valent metal porous functional material prepared in this example, respectively, and the results are shown in Figures 1-2. It can be seen that the carbon composite nano-zero-valent metal porous functional material has rough inner and outer surfaces, rich pore structure and high hydrophilicity, which is very suitable for the reproduction and growth of microorganisms.

The carbon composite nano-zero-valent metal porous functional material has an average mesopore diameter of 10-50 nm and a specific surface area of 120-200 m ² /g measured by nitrogen adsorption and desorption curve. The carbon composite nano-zero-valent metal porous functional material The larger specific surface area is conducive to ion exchange adsorption, so that the load of microorganisms is higher, thereby improving the pollutant removal effect.

Embodiment 2

The preparation method of carbon composite nano-zero-valent metal porous functional material in this embodiment includes the following steps:

The meteorite and sawdust were crushed and sieved to less than 0.0374mm, the meteorite powder and the leaf powder were mixed according to a mass ratio of 2:1 to obtain a mixed powder, and the mixed powder was calcined in a hydrogen atmosphere, and the calcination temperature was 900 ° C , the time is 2h, and the nano-zero-valent metal composite material is prepared;

At the same time, the natural zeolite powder, high-strength Portland cement, quicklime, aluminum powder, gypsum, and surfactant are mixed according to the mass percentages of 50-65%, 20-40%, 3-11%, 0.5-2%, 1- 5% batching, mixing, casting, foaming, and autoclaving at a high temperature of 180 ° C for 8 hours to obtain a composite porous material;

Finally, the surface of the composite porous material was evenly sprinkled with the nano-zero-valent metal composite material, the weight ratio of the nano-zero-valent composite material and the composite porous material was 3:100, and the carbon composite nano-zero-valent metal porous function was obtained by watering and curing for 15 days. Material.

The performance test of the carbon composite nano-zero-valent metal porous functional material prepared in this example is carried out. The results are shown in Table 2. It can be seen from Table 2 that the pores of the carbon composite nano-zero-valent metal porous functional material prepared in this example The rate is 58%-85%, the specific surface area is 70-188m ² /g, and the compressive strength is 66-87N.

Table 2:

Embodiment 3

The preparation method of carbon composite nano-zero-valent metal porous functional material in this embodiment includes the following steps:

The meteorite and the leaves are crushed and sieved to less than 0.0374mm, the meteorite powder and the leaf powder are mixed according to a mass ratio of 1:1 to obtain a mixed powder, and the mixed powder is calcined in a carbon monoxide atmosphere, and the calcination temperature is 400 ° C , the time is 5h, and the nano-zero-valent metal composite material is prepared;

At the same time, the natural zeolite powder, high-strength Portland cement, quicklime, aluminum powder, gypsum, and surfactant are mixed according to the mass percentages of 50-65%, 20-40%, 3-11%, 0.5-2%, 1- 5% batching, mixing, casting, foaming, and autoclaving at a high temperature of 180 ° C for 4 hours to obtain a composite porous material;

Finally, the surface of the composite porous material was evenly sprinkled with the nano-zero-valent metal composite material, the weight ratio of the nano-zero-valent composite material and the composite porous material was 1:95, and the carbon composite nano-zero-valent metal porous function was obtained by watering and curing for 5 days. Material.

The performance test of the carbon composite nano zero-valent metal porous functional material prepared in this example is carried out. The results are shown in Table 3. It can be seen from Table 3 that the pores of the carbon composite nano zero-valent metal porous functional material prepared in this example are The rate is 43%-88%, the specific surface area is 100-248m ² /g, and the compressive strength is 76-97N.

table 3:

Embodiment 4

In this example, the carbon composite nano-zero-valent metal porous functional material prepared in Example 1 and the commercially available constructed wetland matrix were respectively loaded into two constructed wetland systems under the same conditions for pilot-scale operation and comparative test. removal of contaminants. Among them, the influent ammonia nitrogen concentration of the constructed wetland system is 10-300mg/L, the total nitrogen concentration is 10-350mg/L, the COD concentration is 10-200mg/L, and the P concentration is 0.1-5mg/L.

According to the results of the pilot test, the carbon composite nano-zero-valent metal porous functional material-constructed wetland system composed of the carbon composite nano-zero-valent metal porous functional material can achieve a removal rate of more than 97% of ammonia nitrogen and total nitrogen in about one year of operation. The removal rate is over 86%, the COD removal rate is over 94%, and the P removal rate is over 97%. The commercial constructed wetland matrix-constructed wetland system composed of commercially available constructed wetland substrates has a removal rate of 60% for ammonia nitrogen, 36% for total nitrogen, and 64% for COD in about a year. The removal rate was 47%.

The carbon composite nano-zero-valent metal porous functional material prepared by the present invention, as a constructed wetland substrate, has a higher pollutant removal rate than the commercially available constructed wetland substrate, which is mainly due to the carbon composite nano-zero-valent metal The porous functional material has a rough surface and a large porosity, which provides favorable conditions for the reproduction and growth of microorganisms, and is an excellent microbial carrier material; and carbon composite nano-zero-valent metal porous functional materials include porous composite porous materials and active materials. High nano-zero-valent metal composite material, the nano-zero-valent metal composite material can form a multi-metal system, and in the catalytic reaction, each metal can play a synergistic role to improve the catalytic degradation efficiency; and the carbon composite nano-zero The nano-zero-valent Ni in the valence metal porous functional material can be oxidized to Ni ²⁺ , and Ni ²⁺ can also promote the growth of anaerobic microorganisms. In addition, the carbon composite nano-zero-valent metal porous functional material has a large specific surface area, and itself can effectively adsorb, filter, and intercept pollutants.

Embodiment 5

In this example, the carbon composite nano-zero-valent metal porous functional material prepared in Example 1 is used as the matrix of sponge city to treat wastewater, and a pilot-scale operation test is carried out. Removal of nitrogen, phosphorus and other pollutants in wastewater by valence metal porous functional materials. Among them, the influent ammonia nitrogen concentration is 1-100mg/L, the total nitrogen concentration is 1-150mg/L, the COD concentration is 1-100mg/L, and the P concentration is 0.1-10mg/L.

According to the results of the pilot test, the carbon composite nano-zero-valent metal porous functional material-sponge city system composed of the carbon composite nano-zero-valent metal porous functional material can achieve 100% removal rate of ammonia nitrogen and remove total nitrogen after running for about one year. The removal rate reaches 100%, the COD removal rate reaches 100%, and the P removal rate reaches 100%. The commercial sponge city matrix-sponge city system composed of commercially available sponge city matrix has a removal rate of ammonia nitrogen of 40%, total nitrogen removal rate of 34%, and COD removal rate of 50% within a year of operation. The removal rate was 33%.

The test results are: the carbon composite nano-zero-valent metal porous functional material composed of carbon composite nano-zero-valent metal porous functional material-sponge city system has the best effect, with a water holding capacity of 50-60% and an average penetration rate of 5 mm·d ^-1 . Theoretically, in heavy rainstorm weather, it can bear the maximum rainwater infiltration in an area 1-45 times its own area. The concentration of ammonia nitrogen in the effluent is less than 0.1mg·L ^-1 , the concentration of total nitrogen is less than 0.5mg·L ^-1 , and the concentration of total phosphorus is less than 0.05mg· L ^-1 , COD concentration is less than 5mg·L ^-1 , which are all in line with the "Water Quality Index for Urban Wastewater Recycling and Utilization of Urban Miscellaneous Water" (GB/T 18920-2002). Factory Pollutant Discharge Standard (GB 18918-2002), Grade A Standard and "Technical Specifications for Rainwater Control and Utilization Engineering for Buildings and Residential Areas" (GB 50400-2016), except for the water standard for ornamental waterscapes.

The above descriptions are only preferred embodiments of the present invention, which are merely illustrative rather than limiting for the present invention. Those skilled in the art understand that many changes, modifications and even equivalents can be made within the spirit and scope defined by the claims of the present invention, but all fall within the protection scope of the present invention.

Claims (13)

1. The preparation method of the 1, carbon composite nano zero-valent metal porous functional material is characterized by comprising the following steps:

   step S1, the meteorite powder and the biomass powder are used as raw materials to prepare the nano zero-valent metal composite material through reduction and calcination;

   step S2, mixing and proportioning zeolite, cement, quicklime, aluminum powder, gypsum and a surfactant, and preparing the composite porous material through pouring, foaming, cutting and autoclaving maintenance;

   and step S3, uniformly spreading the nano zero-valent metal composite material on the surface of the composite porous material, and naturally curing the composite porous material after water dispersion and curing to obtain the carbon composite nano zero-valent metal porous functional material.
2. 2. The method of claim 1, wherein the nano zero valent metal composite material is obtained by calcining the meteorite powder and the biomass powder in hydrogen or carbon oxide atmosphere in step S1.
3. 3. The preparation method of the carbon composite nano zero-valent metal porous functional material according to claim 2, characterized in that the calcination is carried out in hydrogen or carbon oxide atmosphere, the calcination temperature is 400-900 ℃, and the calcination time is 2-5 h.
4. 4. The method for preparing the carbon composite nano zero-valent metal porous functional material according to claim 1, wherein the particle sizes of the merle powder and the biomass powder in the step S1 are both less than 0.0374 mm.
5. 5. The method for preparing the carbon composite nano zero-valent metal porous functional material according to claim 1, wherein the mass ratio of the meteorite powder to the biomass powder is 1:1-3: 1.
6. 6. The method for preparing the carbon composite nano zero-valent metal porous functional material according to claim 1, wherein the steam curing in the step S2 is performed under the conditions of 1MPa-2MPa for 5-8h at 180 ℃ +/-5 ℃.
7. 7. The method for preparing the carbon composite nano zero-valent metal porous functional material according to claim 1, wherein the mass percentages of the zeolite, the cement, the quicklime, the aluminum powder and the gypsum in the step S2 are respectively 50-65%, 20-40%, 3-11%, 0.5-2% and 1-5%.
8. 8. The method for preparing a carbon composite nano zero-valent metal porous functional material according to claim 1, wherein in the step S3, the nano zero-valent metal composite is uniformly sprinkled on the surface of the composite porous material, and the weight ratio of the nano zero-valent composite to the composite porous material is 1-5: 90-100.
9. 9, carbon composite nano zero-valent metal porous functional materials prepared by the method for preparing the carbon composite nano zero-valent metal porous functional materials as claimed in any of claims 1-8.
10. 10. The carbon composite nano zero-valent metal porous functional material according to claim 9, wherein the carbon composite nano zero-valent metal porous functional material has multi-level pores including micropores of 1nm to 2nm, mesopores of 10nm to 50nm, and macropores of 50nm to 1000 μm.
11. 11. The carbon composite nano zero-valent metal porous functional material according to claim 9, wherein the porosity of the carbon composite nano zero-valent metal porous functional material is 90-99%.
12. 12. The carbon composite nano zero-valent metal porous functional material according to claim 9, wherein the specific surface area of the carbon composite nano zero-valent metal porous functional material is 70-250m²/g。
13. 13, applications of the carbon composite nanometer zero-valent metal porous functional material as claimed in claim 9 in artificial wetland.

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