CN110467276B

CN110467276B - Preparation and application of sulfur autotrophic and heterotrophic denitrification and denitrification biological filler

Info

Publication number: CN110467276B
Application number: CN201910869557.1A
Authority: CN
Inventors: 刘波; 程绍举; 侯玉倩; 张陈永; 王梦良; 杜凌峰
Original assignee: Nanjing University
Current assignee: Nanjing University
Priority date: 2019-09-16
Filing date: 2019-09-16
Publication date: 2021-09-28
Anticipated expiration: 2039-09-16
Also published as: CN110467276A

Abstract

The invention discloses a preparation and application of sulfur autotrophic and heterotrophic denitrification biological filler, which increases the quantity of micropores and silicon hydroxyl on the surface of ceramsite by alkali etching, and then utilizes high-activity disulfide dichloride to carry out activation treatment on the surface of alkali modified ceramsite, wherein the disulfide dichloride can be chemically bonded with hydroxyl functional groups on the surface of the ceramsite, so that sulfur is loaded on the surface of the ceramsite to form Si-O-S and generate crosslinking, and a stable network structure is formed. The sulfur autotrophic and heterotrophic denitrification biological filler provided by the invention can realize the coupling of sulfur autotrophic and heterotrophic denitrification, is beneficial to the attached growth of microorganisms, reduces the addition of carbon sources, improves the population enrichment, further improves the denitrification efficiency and stabilizes the effluent quality.

Description

Preparation and application of sulfur autotrophic and heterotrophic denitrification and denitrification biological filler

Technical Field

The invention belongs to the technical field of advanced treatment and recycling of wastewater, and particularly relates to preparation and application of a sulfur autotrophic and heterotrophic denitrification and denitrification biological filler

Background

The nitrogen pollution in the water body is one of the main problems threatening the quality of the water body in China at present, and the high content of nitrogen causes eutrophication of the water body and the degradation of the water environment quality to threaten the health of people. Biological denitrification is widely applied to deep denitrification due to the characteristics of high efficiency and low cost, and the secondary effluent deep denitrification process of a sewage plant mainly comprises a biological filter, an activated sludge process, an advanced oxidation process, an artificial wetland and the like. The denitrification biological filter has the advantages of small occupied area, high denitrification efficiency, strong adsorption filtration, easy management and operation, low investment cost and the like, and has good application prospect in the field of advanced denitrification of effluent of sewage plants.

The existing denitrification technology is divided into heterotrophic denitrification and autotrophic denitrification, wherein the former uses added organic matters (methanol, ethanol, acetic acid and the like) as denitrification matrixes to solve the problem of poor nutrition of underground water, is a widely researched technology in the field of drinking water denitrification, and has the problems of high treatment capacity of a unit volume reactor, high cost and secondary pollution of residual organic matrixes; the latter is prepared from inorganic carbon such as carbonate and bicarbonate as carbon source, and mainly from inorganic substances (such as H)₂，S^2-，Fe，Fe²⁺Etc.) complete the metabolism of the microorganism as an electron donor for nitrate reduction, reducing nitrate to nitrogen. For example, chinese patent application No. CN201710966083.3 discloses a method for enhancing nitrogen removal by adding organic matters in cooperation with sulfur autotrophic denitrification, comprising the following steps: in the reaction process of the sulfur particles and the calcium carbonate particles, organic matters are added into the water inlet of the reactor, so that sulfur autotrophic denitrifying bacteria and sulfur heterotrophic denitrifying bacteria exist in the reactor at the same time. Specifically, in the reactor, the volume ratio of the sulfur particles to the calcium carbonate particles is 1:0.7, the particle size of the calcium carbonate particles is 1 mm-5 mm, and the particle size of the sulfur particles is 1 mm-8 mm. The added organic matter is sodium acetate, and the sodium acetate is added according to the proportion of C/N which is 2.5. The invention has the following beneficial effects: in the invention, by adding a small amount of organic matters into the inlet water of the reactor, the removal amount of nitrate and nitrogen is increased, and the denitrification effect is obviously enhanced. Although no carbon source needs to be added, certain alkalinity needs to be added, and the required water conservancy retention time is longer to obtain a better treatment effect.

In order to solve the above problems, in recent years, a new trend of using autotrophic denitrification and heterotrophic denitrification technologies in biological denitrification has been developed, for example, chinese patent application No. CN201710966083.3 discloses a sulfur autotrophic denitrification sulfur removal reactor, which uses sulfur particles and calcium carbonate particles as denitrification filter fillers, and adds an external carbon source to intake water to realize the coupling of autotrophic denitrification and heterotrophic denitrification, but the two fillers have a small amount of microorganisms contained in the intake water, and have different densities and particle sizes, and the two fillers are easy to delaminate during backwashing, thereby affecting the nitrogen removal efficiency.

Also, for example, chinese patent application No. CN201710414282.3 discloses a mixed nutrient denitrification filler and a method for preparing and using the same) in which activated carbon, sulfur and a solid carbon source are used as raw materials to prepare a denitrification biological filler, the activated carbon is not favorable for biofilm formation of microorganisms, the amount of microorganisms contained in the system is small, sulfur in the sulfur easily flows out, which causes pollution to a water body, and the microorganisms have low utilization rate of solid carbon sources such as polybutylene succinate, polyhexamethylene lactone, and methyl cellulose, which limits the denitrification rate.

For the denitrification biofilter, the core for the function is the selection of the filler. The filler is generally divided into an organic filler and an inorganic filler, the organic filler comprises polypropylene, polylactic acid and the like, the defects are that the production cost is overhigh, and the biofilm formation difficulty is high, for example, Chinese patent application with application number CN201710980165.3 discloses a water treatment filler capable of synchronously removing ammonia nitrogen and total nitrogen from wastewater. Compared with other inorganic fillers, the ceramsite has the advantages of strong biological adhesiveness, good film forming performance, high mechanical strength, developed macroporous structure, rough surface and the like, and microorganisms are easy to adhere and grow on the surface of the ceramsite, so that good environmental conditions are provided for the growth of denitrifying bacteria.

Ceramsite is used as the filler of the denitrification filter, and the heterotrophic denitrification technology is mostly used for removing nitrogen in water. Heterotrophic denitrification is fast in biofilm formation and denitrification rate, an external carbon source is generally needed, the COD of the effluent water is likely to increase, and the total nitrogen of the effluent water can generally reach the first-level A discharge standard but is difficult to reduce to a lower level. The Chinese patent application with the application number of CN201811017455.9 discloses a method for preparing ceramsite by utilizing solid waste, which combines urban dewatered sludge with other wastes to prepare ceramsite, has lower cost, lower porosity and smaller biological load, and is difficult to achieve high denitrification efficiency when used for a denitrification filter.

The traditional ceramsite is mainly prepared from clay, shale, fly ash, coal mine stripping, loess, sludge and the like serving as main raw materials. After the waste materials and the slag of chemical enterprises adopt the traditional ceramsite preparation process, the produced ceramsite has unsatisfactory use effect, for example, the ceramsite which is manufactured by taking fly ash or coal mine stripping materials as basic raw materials in the prior art has poor ceramsite strength, so that the practicability is not strong. And the ceramsite is simply used as the biological filler, so that the water treatment effect is extremely limited.

Therefore, a new high-efficiency denitrification biological filler is urgently needed to be developed, and has extremely important significance in the application of the high-efficiency denitrification biological filler to wastewater treatment.

Disclosure of Invention

1. Problems to be solved

The invention aims to provide a high-efficiency denitrification biological filler, which can realize the coupling of sulfur autotrophy and heterotrophic denitrification in the denitrification treatment of wastewater;

meanwhile, the invention provides a preparation method of the high-efficiency denitrification biological filler;

meanwhile, the biological filler is applied to wastewater denitrification treatment, so that the treatment efficiency is ensured, and the problems of long biological film forming time, difficulty in further improvement of treatment efficiency, uneven biological film distribution, secondary effluent pollution, high effluent sulfate radical, filler layering and the like in the conventional denitrification, sulfur autotrophic and heterotrophic coupling denitrification water treatment technology are solved.

2. Technical scheme

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a sulfur autotrophic and heterotrophic denitrification biological filler is characterized in that: the biological filler is sulfur modified ceramsite with sulfur loaded on the surface, and the sulfur is combined with Si and O elements on the surface of the ceramsite through valence bonds to form Si-O-S.

Preferably, Si-O-S crosslinking on the surface of the biological filler forms a grid structure on the surface of the ceramsite.

The preparation method of the sulfur autotrophic and heterotrophic denitrification biological filler comprises the following steps:

(1) alkali modification: soaking the primary ceramsite by using potassium hydroxide, and washing with water after soaking to obtain alkali modified ceramsite;

(2) and (3) sulfur loading: dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dropwise adding disulfide dichloride, heating and stirring, obtaining the sulfur autotrophic and heterotrophic denitrification and denitrification biological filler after the reaction is finished, and continuously introducing nitrogen in the reaction process.

Adding disulfide dichloride to react with silicon hydroxyl on the surface of the modified ceramsite, isolating oxygen and continuously introducing nitrogen in the reaction process, simultaneously manufacturing a certain pressure environment by isolating oxygen, and performing cross-linking reaction on single and double sulfur bonds on the surface of the ceramsite by hot pressing to prepare the sulfur autotrophic and heterotrophic denitrification biological filler with a grid structure.

Preferably, the mass ratio of the disulfide dichloride to the primary ceramsite in the step (2) is 1 (5-6) based on the amount of the primary ceramsite used in the step (1).

Preferably, in the step (2), the dropping speed of the disulfide dichloride is 0.6-0.8 mL/min, and the speed of introducing nitrogen is 8-12L/min.

Preferably, in the step (2), the heating temperature is 50-60 ℃, the stirring time is 10 hours, and the stirring speed is 100-150 r/min. It should be noted here that the heating temperature, the stirring time, and the stirring speed in this step are key for determining whether the sulfur loading and the sulfur loading effect can be achieved, and because the ceramsite particles are large, the surface of the ceramsite contains a plurality of silicon hydroxyl groups after being subjected to alkali modification, and the space positions of the silicon hydroxyl groups are different, the heating temperature, the stirring time, and the stirring speed in this step cannot be changed at will, otherwise, the sulfur loading failure is caused, or the sulfur loading cannot form a sulfur-loaded network structure on the surface of the ceramsite in time.

Preferably, the preparation method of the sulfur autotrophic and heterotrophic denitrification biological filler comprises the following specific steps:

(1) firing:

mixing and grinding the ceramsite raw material and a binder to prepare raw material powder, and drying and cooling the raw material powder;

preparing the raw material powder into raw material balls with the diameter of 2-3 mm by a disc type ball making machine, and drying and cooling;

preheating the raw material balls in a muffle furnace at 300-400 ℃ for 20-30 min;

roasting the preheated raw material balls in a muffle furnace at 900-1000 ℃ for 15-20 min to obtain primary ceramsite;

it should be noted that the temperature and time of the first stage of calcination are extremely important for the firing molding rate of the ceramsite, the formation of the surface voids of the ceramsite and the uniformity of the voids, and the preheating can remove some surface water and part of bound water, so that the voids of the ceramsite raw material are more uniform, and the molding rate of the later stage firing is improved;

wherein the mass ratio of the ceramsite raw material to the binder is (20-25): 1; the ceramsite raw material is a substance containing silicon dioxide, including biological dewatered sludge, clay, fly ash or garbage residues; the binder is bentonite, and the bentonite is one or more of calcium bentonite, sodium bentonite or organic bentonite. The bentonite is selected as the binder, so that the strength of the ceramsite can be improved.

(2) Alkali modification:

putting the ceramsite in the last step into 2% -3% of potassium hydroxide (relative molecular weight is 40) solution for reaction for 24 hours, and after soaking, carrying out water-based treatment on the ceramsite until the pH value of a washing solution is 6.9-7.1 to obtain alkali-modified ceramsite;

(3) and (3) sulfur loading:

placing petroleum ether in a reaction kettle, dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dropping a disulfide dichloride reagent, stirring for 10 hours at the temperature of 50-60 ℃, wherein the stirring speed is 100-150 r/min, continuously introducing nitrogen in the reaction process, isolating air, and obtaining the ceramsite loaded with sulfur after the reaction is finished;

it should be noted that the heating temperature, the stirring time and the stirring speed in this step are critical in determining whether the sulfur loading and the sulfur loading effect can be achieved, and because the ceramsite particles are large, the surface of the ceramsite contains a plurality of silicon hydroxyl groups after being subjected to alkali modification, and the space positions of the silicon hydroxyl groups are different, the heating temperature, the stirring time and the stirring speed in this step cannot be changed at will, otherwise, the sulfur loading failure is caused, or a sulfur-loaded network structure cannot be formed on the surface of the ceramsite even if the sulfur loading is achieved.

(4) Cleaning:

and (3) washing the ceramsite loaded with the sulfur by using a cleaning agent for 1-2 times, then washing the ceramsite by using absolute ethyl alcohol for 5-6 times, and then drying the ceramsite in a vacuum drying oven for 8 hours to obtain the sulfur autotrophic and heterotrophic denitrification biological filler, namely the sulfur modified ceramsite.

The cleaning agent is a water-based cleaning agent, the water-based cleaning agent is one of sodium alkyl benzene sulfonate and fatty alcohol sodium sulfate, and the purpose is to clean the residual disulfur dichloride on the surface of the sulfur-loaded ceramsite;

it should be noted here that, if ethanol is directly used for cleaning, some chlorine disulfide remains on the surface of the sulfur-loaded ceramsite, and thorough cleaning cannot be achieved, and even if ethanol with different gradient concentrations is used for multiple times of cleaning, chlorine disulfide remains.

The biological filler for denitrification is applied to sewage treatment as the biological filler for high-efficiency sulfur autotrophic and heterotrophic denitrification.

3. Advantageous effects

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention provides a sulfur autotrophic and heterotrophic denitrification and denitrification biological filler, which is a sulfur modified ceramsite sequentially subjected to alkali modification and sulfur loading treatment; firstly, carrying out alkali modification treatment on the ceramsite to generate a large amount of silicon hydroxyl on the surface of the ceramsite, so that sulfur loading is facilitated; the sulfur is stably loaded on the surface of the ceramsite to form a stable net structure, can be used as a biological filler for high-efficiency sulfur autotrophic and heterotrophic denitrification for application in wastewater treatment, and can realize the coupling of sulfur autotrophic and heterotrophic denitrification; compared with sulfur and pyrite, the sulfur is not easy to dissolve out, can be slowly utilized by sulfur autotrophic denitrifying bacteria, and cannot influence the effluent quality; the method is beneficial to the attached growth of microorganisms, reduces the addition of carbon sources, improves the population abundance, further improves the denitrification efficiency and stabilizes the effluent quality; meanwhile, autotrophic and heterotrophic denitrifying bacteria are uniformly distributed on the surface of the ceramsite, so that the problem of layering after backwashing is solved, and the denitrification and operation effects are stable.

(2) The preparation method of the sulfur autotrophic and heterotrophic denitrification and denitrification biological filler provided by the invention has the advantages that the potassium hydroxide is adopted to modify the primary ceramsite, and the potassium hydroxide can react with the aluminum oxide and the silicon dioxide in the ceramsite to generate soluble silicate (aluminate), so that more micropores are formed on the surface of the ceramsite by etching, the specific surface area of the ceramsite is increased, and meanwhile, a large amount of silicon hydroxyl groups are generated on the surface of the ceramsite, thereby facilitating the loading of sulfur; the method is characterized in that disulfur dichloride is used as a sulfur source, the surface of alkali modified ceramsite is activated under reasonable experimental conditions and parameter control, the disulfur dichloride can be chemically bonded with hydroxyl functional groups on the surface of the ceramsite, sulfur is loaded on the surface of the ceramsite, sulfur atoms firstly form Si-O-S covalent bonds on the surface of the ceramsite, and then single sulfur bonds and disulfide bonds on the surface of the ceramsite are crosslinked, so that a large number of sulfur atoms are fixed on the surface of the ceramsite to form a stable network structure.

(3) The preparation method of the sulfur autotrophic and heterotrophic denitrification biological filler provided by the invention takes the substances containing a large amount of silicon dioxide, such as biological dewatered sludge, clay, fly ash or garbage residues, and the like as the raw materials of the ceramsite, has wide sources and low price, and has a certain waste recycling effect;

the bentonite is used as a binder in the firing process of the ceramsite, and two-stage temperature programming treatment (constant temperature heat preservation treatment of the raw material balls at 300-400 ℃ for 20-30 min, and then constant temperature heat preservation treatment at 900-1000 ℃ for 15-20 min) is adopted in the firing process, so that the mechanical strength of the primary ceramsite can be improved under the synergistic effect of the bentonite and the raw material balls, and the primary ceramsite is stable in structure and not easy to crack in subsequent treatment.

(4) The sulfur autotrophic and heterotrophic denitrification biological filler provided by the invention is used for water treatment, more micropores are formed on the surface of the ceramsite etched by alkali, and the surface area is larger, so that denitrifying bacteria are easier to attach and grow, the film formation time is shortened, and the denitrification effect is improved.

Drawings

FIG. 1 is a schematic diagram showing the total nitrogen removal rate of effluent after wastewater treatment using the four materials described in example 15 and comparative example 3 as biological fillers, respectively;

FIG. 2 is a schematic diagram of the preparation of sulfur autotrophic and heterotrophic denitrification biological filler.

Detailed Description

The primary ceramsite is ceramsite subjected to alkali modification and sulfur loading treatment;

the ceramsite raw material is a substance containing silicon dioxide, including biological dewatered sludge, clay, fly ash or garbage residues;

the 'binder' is bentonite, and the bentonite is one or more of calcium bentonite, sodium bentonite or organic bentonite;

the invention is further described with reference to specific examples.

Example 1

As shown in FIG. 2, the embodiment provides a sulfur autotrophic and heterotrophic denitrification biological filler, which is a sulfur-modified ceramsite loaded with sulfur on the surface, wherein the sulfur is combined with Si and O elements on the surface of the ceramsite to form Si-O-S, and the Si-O-S are crosslinked with each other to form a grid structure. The preparation method of the sulfur-modified sulfur autotrophic and heterotrophic denitrification denitrogenation biological filler in the embodiment is as follows:

(1) alkali modification:

soaking the primary ceramsite by using a potassium hydroxide solution, and washing with water after soaking to obtain alkali modified ceramsite;

(2) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride, heating and stirring, obtaining sulfur-loaded sulfur modified ceramsite after the reaction is finished, and continuously introducing nitrogen in the reaction process.

Example 2

The embodiment provides a sulfur autotrophic and heterotrophic denitrification and denitrification biological filler, which is a sulfur-modified ceramsite sequentially subjected to alkali modification and sulfur loading treatment.

The preparation method of the sulfur autotrophic and heterotrophic denitrification denitrogenation biological filler in the embodiment is as follows:

(1) firing:

adding a binder calcium-based bentonite into the dewatered sludge and clay of the ceramsite raw material to prepare raw material powder, preparing the raw material powder into raw material balls, and roasting the raw material balls at high temperature to obtain primary ceramsite; the mass ratio of the ceramsite raw material to the binder is 20: 1.

(2) alkali modification:

soaking the primary ceramsite by using a potassium hydroxide solution with the mass concentration of 2%, and washing with water after soaking to obtain alkali modified ceramsite;

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride at a dropping rate of 0.6-0.8 mL/min, heating and stirring, obtaining the ceramsite loaded with sulfur after the reaction is finished, and continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction rate is 8-12L/min; the mass ratio of the disulfide dichloride to the primary ceramsite is 1: 5;

(4) cleaning:

and (3) washing the ceramsite loaded with the sulfur by using a cleaning agent sodium alkyl benzene sulfonate, washing the ceramsite by using absolute ethyl alcohol, and then drying the ceramsite in vacuum to obtain the sulfur modified ceramsite.

Example 3

The embodiment provides a biological filler, which is a sulfur-modified ceramsite sequentially subjected to alkali modification and sulfur loading treatment.

(1) firing:

adding a binder sodium bentonite into ceramsite raw material fly ash and garbage residues to prepare raw material powder, preparing the raw material powder into raw material balls, and roasting the raw material balls at high temperature to obtain primary ceramsite; the mass ratio of the ceramsite raw material to the binder is 25: 1.

(2) alkali modification:

soaking the primary ceramsite by using a potassium hydroxide solution with the mass concentration of 3%, and washing with water after soaking to obtain alkali modified ceramsite;

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride at a dropping rate of 0.6-0.8 mL/min, heating and stirring, obtaining the ceramsite loaded with sulfur after the reaction is finished, and continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction rate is 8-12L/min; the mass ratio of the disulfide dichloride to the primary ceramsite is 1: 6;

(4) cleaning:

and (3) washing the ceramsite loaded with the sulfur by using a detergent, namely fatty alcohol sodium sulfate, washing the ceramsite with absolute ethyl alcohol, and then drying the ceramsite in vacuum to obtain the sulfur modified ceramsite.

Example 4

(1) firing:

adding organic bentonite as a binder into ceramsite raw material clay, fly ash and garbage residues to prepare raw material powder, preparing the raw material powder into raw material balls, and roasting the raw material balls at high temperature to obtain primary ceramsite; the mass ratio of the ceramsite raw material to the binder is 23: 1.

(2) alkali modification:

soaking the primary ceramsite by using a potassium hydroxide solution with the mass concentration of 2.5%, and washing with water after soaking to obtain alkali modified ceramsite;

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride at a dropping rate of 0.6-0.8 mL/min, heating and stirring, obtaining the ceramsite loaded with sulfur after the reaction is finished, and continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction rate is 8-12L/min; the mass ratio of the disulfide dichloride to the primary ceramsite is 1: 5.5;

(4) cleaning:

and (3) washing the ceramsite loaded with the sulfur by using a cleaning agent, then washing the ceramsite by using absolute ethyl alcohol, and then drying the ceramsite in vacuum to obtain the sulfur modified ceramsite.

Example 5

(1) firing:

mixing ceramsite raw materials and calcium bentonite according to the proportion of 24: 1, mixing and grinding the raw materials to prepare raw material powder, drying and cooling;

preheating the raw material balls in a muffle furnace at 300 ℃ for 20 min;

roasting the preheated raw material balls in a muffle furnace at 900 ℃ for 15min to obtain primary ceramsite;

(2) alkali modification: placing the primary ceramsite into a potassium hydroxide solution with the mass concentration of 2% to be soaked for 24 hours, washing the primary ceramsite with distilled water after soaking is completed until the pH value of the washing solution is 6.9-7.1, drying and cooling the primary ceramsite to obtain alkali modified ceramsite;

(3) and (3) sulfur loading: dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride, wherein the mass ratio of the use mass of the disulfide dichloride to the primary ceramsite is 1: 5, dropwise adding at a speed of 0.6-0.8 mL/min, stirring at 50 ℃ for 10 hours at a stirring speed of 100r/min, obtaining the sulfur-loaded ceramsite after the reaction is finished, continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction speed is 8-12L/min, and obtaining the sulfur-loaded ceramsite after the reaction is finished;

(4) cleaning:

and (3) washing the ceramsite loaded with the sulfur with sodium alkyl benzene sulfonate for 2 times, then washing with absolute ethyl alcohol for 5 times, and then drying in a vacuum drying oven for 8 hours to obtain the sulfur modified ceramsite.

The ceramsite prepared in the embodiment has high molding rate, the formation rate of the gaps on the surface of the ceramsite is high, and the gaps of the ceramsite raw material are more uniform.

Example 6

(1) firing:

preheating the raw material balls in a muffle furnace at 400 ℃ for 15 min;

(2) alkali modification:

placing the primary ceramsite into a potassium hydroxide solution with the mass concentration of 2% to be soaked for 24 hours, washing the primary ceramsite with distilled water after soaking is completed until the pH value of the washing solution is 6.9-7.1, drying and cooling the primary ceramsite to obtain alkali modified ceramsite;

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride, wherein the mass ratio of the disulfide dichloride to the primary ceramsite is 1: 5; after the reaction is finished, dropwise adding the mixture at the speed of 0.6-0.8 mL/min, stirring at 50 ℃ for 10 hours at the stirring speed of 100r/min to obtain the sulfur-loaded ceramsite, continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction speed is 8-12L/min to obtain the sulfur-loaded ceramsite;

(4) cleaning:

Example 7

(1) firing:

preheating the raw material balls in a muffle furnace at 350 ℃ for 30 min;

(2) alkali modification:

(3) and (3) sulfur loading:

sulfur loading, namely dispersing alkali modified ceramsite in a petroleum ether solvent, and slowly adding disulfide dichloride, wherein the mass ratio of the use mass of the disulfide dichloride to the primary ceramsite is 1: 5, dropwise adding at a speed of 0.6-0.8 mL/min, stirring at 50 ℃ for 10 hours at a stirring speed of 100r/min, obtaining the sulfur-loaded ceramsite after the reaction is finished, continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction speed is 8-12L/min, and obtaining the sulfur-loaded ceramsite after the reaction is finished;

(4) cleaning:

Example 8

(1) firing:

preheating the raw material balls in a muffle furnace at 350 ℃ for 30 min;

roasting the preheated raw material balls in a muffle furnace at 1000 ℃ for 20min to obtain primary ceramsite;

(2) alkali modification:

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride, wherein the mass ratio of the use mass of the disulfide dichloride to the primary ceramsite is 1: 5, dropwise adding at a speed of 0.6-0.8 mL/min, stirring at 50 ℃ for 10 hours at a stirring speed of 100r/min, obtaining the sulfur-loaded ceramsite after the reaction is finished, continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction speed is 8-12L/min, and obtaining the sulfur-loaded ceramsite after the reaction is finished;

(4) cleaning:

The ceramsite prepared in the embodiment has high molding rate, the formation rate of the surface gaps of the ceramsite is high, and the gaps of the ceramsite raw material are more uniform.

Comparative example 1

Compared with example 5, the comparative example differs only in that:

(1) the firing steps are different:

respectively treating the raw material balls in muffle furnaces at 100 ℃, 150 ℃, 200 ℃, 250 ℃, 500 ℃, 600 ℃ and 700 ℃, and preheating for 20 min;

roasting the preheated raw material balls in a muffle furnace at 900 ℃ for 15min to obtain primary ceramsite; however, the primary ceramsite obtained by the above-mentioned batch processing is doped with a certain amount of ceramsite fragments, and the amount of the complete ceramsite is very small.

Example 9

(1) firing:

mixing ceramsite raw materials and calcium bentonite according to the weight ratio of 25: 1, mixing and grinding the raw materials to prepare raw material powder, drying and cooling;

preheating the raw material balls in a muffle furnace at 350 ℃ for 25 min;

(2) alkali modification:

placing the primary ceramsite into a potassium hydroxide solution with the mass concentration of 3% to be soaked for 24 hours, washing the primary ceramsite with distilled water after soaking is completed until the pH value of the washing solution is 6.9-7.1, drying the primary ceramsite for 2 hours at 105 ℃, and cooling the primary ceramsite to room temperature to obtain alkali modified ceramsite;

(3) and (3) sulfur loading:

(4) cleaning:

and (3) washing the ceramsite loaded with the sulfur with sodium alkyl benzene sulfonate for 2 times, then washing with absolute ethyl alcohol for 6 times, and then drying in a vacuum drying oven for 8 hours to obtain the sulfur modified ceramsite.

The sulfur-modified ceramsite prepared in the example is successfully loaded with sulfur on the surface, and a sulfur-loaded network structure is formed on the surface of the ceramsite.

Example 10

(1) firing:

preheating the raw material balls in a muffle furnace at 350 ℃ for 25 min;

(2) alkali modification:

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride, wherein the mass ratio of the use mass of the disulfide dichloride to the primary ceramsite is 1: 5, dropwise adding at a speed of 0.6-0.8 mL/min, stirring at 60 ℃ for 10 hours at a stirring speed of 100r/min, obtaining the sulfur-loaded ceramsite after the reaction is finished, continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction speed is 8-12L/min, and obtaining the sulfur-loaded ceramsite after the reaction is finished;

(4) cleaning:

Example 11

(1) firing:

preheating the raw material balls in a muffle furnace at 350 ℃ for 25 min;

(2) alkali modification:

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride, wherein the mass ratio of the use mass of the disulfide dichloride to the primary ceramsite is 1: 5, dropwise adding at a speed of 0.6-0.8 mL/min, stirring at 55 ℃ for 10 hours at a stirring speed of 100r/min, obtaining the sulfur-loaded ceramsite after the reaction is finished, continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction speed is 8-12L/min, and obtaining the sulfur-loaded ceramsite after the reaction is finished;

(4) cleaning:

Example 12

(1) firing:

preheating the raw material balls in a muffle furnace at 350 ℃ for 25 min;

(2) alkali modification:

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride, wherein the mass ratio of the use mass of the disulfide dichloride to the primary ceramsite is 1: 5, dropwise adding at a speed of 0.6-0.8 mL/min, stirring at 50 ℃ for 10 hours at a stirring speed of 150r/min, obtaining the sulfur-loaded ceramsite after the reaction is finished, continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction speed is 8-12L/min, and obtaining the sulfur-loaded ceramsite after the reaction is finished;

(4) cleaning of

Example 13

(1) firing:

preheating the raw material balls in a muffle furnace at 350 ℃ for 25 min;

(2) alkali modification:

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride, wherein the mass ratio of the use mass of the disulfide dichloride to the primary ceramsite is 1: 5, dropwise adding at a speed of 0.6-0.8 mL/min, stirring at 50 ℃ for 10h at a stirring speed of 125r/min, obtaining the sulfur-loaded ceramsite after the reaction is finished, continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction speed is 8-12L/min, and obtaining the sulfur-loaded ceramsite after the reaction is finished;

(4) cleaning:

Example 14

(1) firing:

preheating the raw material balls in a muffle furnace at 350 ℃ for 25 min;

(2) alkali modification:

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly adding disulfide dichloride, wherein the mass ratio of the use mass of the disulfide dichloride to the primary ceramsite is 1: 5, dropwise adding at a speed of 0.6-0.8 mL/min, stirring at 50 ℃ for 15h at a stirring speed of 100r/min, obtaining the sulfur-loaded ceramsite after the reaction is finished, continuously introducing nitrogen during the reaction process, wherein the nitrogen introduction speed is 8-12L/min, and obtaining the sulfur-loaded ceramsite after the reaction is finished;

(4) cleaning:

Comparative example 2

This comparative example provides a biological filler which is comparable to and differs from example 9 only in that

(3) The sulfur loading steps are different, and specifically comprise the following steps:

the first method comprises the following steps: dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dripping a disulfide dichloride reagent, stirring for 10 hours at the temperature of 30 ℃, wherein the stirring speed is 100r/min, continuously introducing nitrogen in the reaction process, and obtaining ceramsite 1 after the reaction is finished;

and the second method comprises the following steps: dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dripping a disulfide dichloride reagent, stirring for 10 hours at 40 ℃, wherein the stirring speed is 100r/min, continuously introducing nitrogen in the reaction process, and obtaining ceramsite 2 after the reaction is finished;

and the third is that: dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dripping a disulfide dichloride reagent, stirring for 10 hours at 70 ℃, wherein the stirring speed is 100r/min, continuously introducing nitrogen in the reaction process, and obtaining ceramsite 3 after the reaction is finished;

and fourthly: dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dripping a disulfide dichloride reagent, stirring for 10 hours at the temperature of 80 ℃, wherein the stirring speed is 100r/min, continuously introducing nitrogen in the reaction process, and obtaining ceramsite 4 after the reaction is finished;

and a fifth mode: dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dripping a disulfide dichloride reagent, stirring for 10 hours at 50 ℃, wherein the stirring speed is 50r/min, continuously introducing nitrogen in the reaction process, and obtaining ceramsite 5 after the reaction is finished;

and a sixth mode: dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dripping a disulfide dichloride reagent, stirring for 10 hours at 50 ℃, wherein the stirring speed is 80r/min, continuously introducing nitrogen in the reaction process, and obtaining ceramsite 6 after the reaction is finished;

seventh, the method comprises: dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dripping a disulfide dichloride reagent, stirring for 10 hours at 50 ℃, wherein the stirring speed is 300r/min, continuously introducing nitrogen in the reaction process, and obtaining ceramsite 7 after the reaction is finished;

the detection shows that no sulfur is successfully loaded on the surfaces of the ceramsite 1-7, or the loaded sulfur is less, or a net-shaped structure is not formed.

Example 15

In the embodiment, 3 sulfur autotrophic and heterotrophic denitrification and denitrification biological fillers are prepared, and 3 biological fillers are utilized for water treatment; the reactor is made of organic glass, the total height is 65cm, the inner diameter is 5cm, the filling height of the biological filler is 50cm, and the effective volume is 800 mL;

when the reactor runs, the water flow is in an upward flow mode, the membrane hanging method is adopted for membrane hanging starting, manual water distribution is adopted for water inlet, the total nitrogen is about 30mg/L, sodium acetate is added as a supplementary carbon source (C/N is 3:1), the reactor runs at the temperature of 25 ℃, the hydraulic retention time is 2h, DO is 0.5mg/L, the reactor runs stably for 30d, and the average nitrogen removal rate and the effluent sulfate radical content are calculated.

The first method comprises the following steps: sulfur autotrophic and heterotrophic denitrification biological filler-primary ceramsite 1

Firing:

(1) mixing 50 parts by weight of clay and 2 parts by weight of calcium bentonite, grinding to obtain raw material powder, drying at 105 ℃, and cooling to room temperature.

(2) And (3) preparing the raw material powder into raw material balls with the diameter of 2-3 mm by a disc type ball making machine, and drying and cooling for 2 hours.

(3) The green pellets were preheated in a muffle furnace at 350 ℃ for 25 min.

(4) And roasting the preheated raw material balls in a muffle furnace at 1000 ℃ for 20min to obtain primary ceramsite 1.

And the second method comprises the following steps: sulfur autotrophic and heterotrophic denitrification biological filler-sulfur modified ceramsite 1

The firing method is the same as the preparation method of the primary ceramsite 1;

alkali modification and sulfur loading:

(1) putting the first filler into a 3% potassium hydroxide solution for reaction for 24 hours,

(2) and (3) repeatedly washing the ceramsite treated by the potassium hydroxide solution with distilled water to ensure that the pH value of the solution is 6.9-7.1, drying the solution at 105 ℃ for 2 hours, and cooling the solution to room temperature to obtain the alkali modified ceramsite 1.

(3) Dispersing the alkali modified ceramsite 1 in a petroleum ether solvent, and slowly dripping a disulfide dichloride reagent, wherein the mass ratio of the use mass of disulfide dichloride to the mass of primary ceramsite is 1: and 5, controlling the dropping rate to be 0.6-0.8 mL/min, stirring, heating and reacting for 10h, wherein the heating temperature is 50 ℃, continuously introducing nitrogen in the reaction process to protect the reaction, and the nitrogen introducing rate is 8-12L/min, and obtaining a reaction product after the reaction is finished.

(4) And washing the reaction product for 2 times by using a sodium alkyl benzene sulfonate cleaning agent, and then washing the reaction product for 6 times by using absolute ethyl alcohol.

(5) And drying the washed reaction product in a vacuum drying oven for 8 hours to obtain the sulfur modified ceramsite 1.

And the third is that: sulfur autotrophic and heterotrophic denitrification biological filler-sulfur modified ceramsite 2

Firing:

(1) mixing and grinding 30 parts by weight of clay, 30 parts by weight of fly ash and 2 parts by weight of sodium bentonite to prepare raw material powder, drying at 105 ℃, and cooling to room temperature.

(3) The green pellets were preheated in a muffle furnace at 400 ℃ for 30 min.

(4) And roasting the preheated raw material balls in a muffle furnace at 1000 ℃ for 25min to obtain the ceramsite 2.

(5) Putting the ceramsite 2 into a 3 percent potassium hydroxide solution for reaction for 24 hours,

(6) and (3) repeatedly washing the ceramsite 2 treated by the potassium hydroxide solution with distilled water to ensure that the pH value of the solution is 6.9-7.1, drying for 2h at 105 ℃, and cooling to room temperature to obtain the alkali modified ceramsite 2.

(7) Dispersing the alkali modified ceramsite 2 into a petroleum ether solvent, and slowly dripping a disulfide dichloride reagent, wherein the mass ratio of the use mass of disulfide dichloride to the mass of primary ceramsite is 1: and 5, controlling the dropping rate to be 0.6-0.8 mL/min, stirring, heating and reacting for 10 hours, wherein the heating temperature is 60 ℃, continuously introducing nitrogen in the reaction process to protect the reaction, and the nitrogen introducing rate is 8-12L/min.

(8) And washing the reaction product for 2 times by using a sodium alkyl benzene sulfonate cleaning agent, and then washing the reaction product for 6 times by using absolute ethyl alcohol.

(9) And drying the washed reaction product in a vacuum drying oven for 8 hours to obtain the sulfur modified ceramsite 2.

The primary ceramsite 1 is filled into a denitrification reactor, the reactor is named as R1, after the stable operation is carried out for 30 days, the average nitrogen removal rate of effluent is 55%, and the sulfate radical of the effluent is about 39 mg/L.

The sulfur modified ceramsite 1 is filled into a denitrification reactor, the reactor is named as R3, after the reactor is stably operated for 30 days, the average nitrogen removal rate of effluent is 81.33%, and the sulfate radical of the effluent is about 92 mg/L.

The sulfur modified ceramsite 2 is filled into a denitrification reactor, the reactor is named as R4, after the reactor is stably operated for 30 days, the average nitrogen removal rate of effluent is 79.32%, and the sulfate radical of the effluent is about 87 mg/L.

Comparative example 3

The present example provides a new biological filler: a mixture of sulphur particles and primary ceramsite 1;

the reactor and the reactor were operated in the same manner as in example 15;

the sulfur is sulfur particles with the particle size of 2-3 mm, the sulfur and the ceramsite 1 are mixed according to the volume ratio of 1:1, the mixture is filled into a denitrification reactor, the reactor is named as R2, the filling mode and the operation conditions of the reactor are the same as those of the comparative example 1, after the stable operation is carried out for 30 days, the average nitrogen removal rate of effluent is 65.88%, and the sulfate radical of the effluent is about 237 mg/L.

As shown in figure 1, by integrating R1, R2, R3 and R4, the removal efficiency of the sulfur-modified ceramsite 1 and the sulfur-modified ceramsite 2 to total nitrogen is 20-30% higher than that of the primary ceramsite 1 and the primary ceramsite 1 plus sulfur, and the effluent sulfate is 80-90 mg/L lower than that of a ceramsite plus sulfur reactor, and meets the requirement of sulfate effluent standard (SO 42-250 mg/L) in the Drinking Water Standard (GB 5749-2006).

Claims

1. A sulfur autotrophic and heterotrophic denitrification biological filler is characterized in that: the biological filler is sulfur modified ceramsite with sulfur loaded on the surface, the sulfur is combined with Si and O elements on the surface of the ceramsite through valence bonds to form Si-O-S, the Si-O-S is crosslinked, and a grid structure is formed on the surface of the ceramsite;

the preparation of the biological filler comprises the following steps:

(1) alkali modification: soaking the primary ceramsite by using a potassium hydroxide solution, and washing with water after soaking to obtain alkali modified ceramsite;

(2) and (3) sulfur loading: dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dropwise adding disulfide dichloride, heating and stirring, obtaining sulfur modified ceramsite after the reaction is finished, and continuously introducing nitrogen in the reaction process;

wherein in the step (2), the heating temperature is 50-60 ℃;

the stirring time is 10 hours, and the stirring speed is 100-150 r/min.

2. The sulfur autotrophic and heterotrophic denitrification denitrogenation biological filler according to claim 1, wherein: and (3) taking the using amount of the primary ceramsite as a reference, wherein the mass ratio of the disulfide dichloride to the primary ceramsite in the step (2) is 1 (5-6).

3. The sulfur autotrophic and heterotrophic denitrification denitrogenation biological filler according to claim 1, wherein: in the step (2), the dropping speed of the disulfide dichloride is 0.6-0.8 mL/min, and the introducing speed of nitrogen is 8-12L/min.

4. The sulfur autotrophic and heterotrophic denitrification and denitrification biological filler according to any one of claims 1-3, wherein: the method comprises the following specific steps:

(1) firing:

adding a binder into the ceramsite raw material to prepare raw material powder, and preparing the raw material powder into raw material balls;

(2) alkali modification:

soaking the primary ceramsite in a potassium hydroxide solution with the mass concentration of 2-3%, and after soaking, carrying out water-based treatment on the ceramsite until the pH value of a washing solution is 6.9-7.1;

(3) and (3) sulfur loading:

dispersing the alkali modified ceramsite in a petroleum ether solvent, slowly dripping a disulfide dichloride reagent, stirring at the temperature of 50-60 ℃ for 10 hours at the stirring speed of 100-150 r/min, continuously introducing nitrogen in the reaction process, and obtaining the ceramsite loaded with sulfur after the reaction is finished;

(4) cleaning:

and (3) washing the ceramsite loaded with the sulfur by using a cleaning agent for 1-2 times, then washing the ceramsite by using absolute ethyl alcohol for 5-6 times, and then drying the ceramsite in a vacuum drying oven for 8 hours to obtain the sulfur modified ceramsite.

5. The sulfur autotrophic and heterotrophic denitrification and denitrification biological filler according to any one of claims 1-3, wherein: the biological filler is used as a biological filler for high-efficiency sulfur autotrophic denitrification and denitrification for sewage treatment.