CN106032521A

CN106032521A - Method for culturing microalgae and combined method for denitration of industrial exhaust gas

Info

Publication number: CN106032521A
Application number: CN201510113349.0A
Authority: CN
Inventors: 荣峻峰; 朱俊英; 周旭华; 纪洪波
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2015-03-16
Filing date: 2015-03-16
Publication date: 2016-10-19
Anticipated expiration: 2035-03-16
Also published as: CN106032521B

Abstract

The invention relates to a method for culturing microalgae and a combined method for denitration of industrial exhaust gas. The culturing method includes: in a medium for culturing microalgae, providing at least one of nitrogen source, phosphorus source and carbon source in the form of alkali metal nutrient salt; and in a culturing process, regulating the pH value of the algae liquid by using nitric acid and / or nitrous acid. The culturing method of the invention can improve the efficiency of microalgae culturing.

Description

The method of cultivating microalgae and method united with industrial waste gas denitration thereof

Technical field

The present invention relates to a kind of a kind of method and cultivating microalgae and the united method of industrial waste gas denitration of cultivating microalgae.

Background technology

The energy " with " environment " be the major issue that new century human society in sustainable development is faced, on the one hand, support mankind's modern civilization fossil energy be non-renewable, thus countries in the world stepping up develop alternative energy source technology；On the other hand, the mankind are inevitably generated the emission problem of serious waste gas and sewage when processing and use fossil energy, and the living environment of weather and the mankind has been had resulted in serious impact.These problems need the solution made overall plans and coordinate.

Microalgae is " chemical plant lived " that driven by sunlight of ultrahigh in efficiency, by the efficient photosynthesis of microalgae cell, converts light energy into the chemical energy of the organic compound such as fat or starch, and releases O₂.Utilize microalgae to produce bioenergy and can reach " substitute fossil energy and reduce the discharge of industrial waste gas " dual purpose with chemicals simultaneously.

But, during the large-scale cultivation of microalgae, often there is a lot of problem, constrain the development of microalgae bioenergy.Practice have shown that: the offer form in nitrogen source can have a strong impact on the effect cultivating microalgae.If nitrogen source provides with the form of ammonium salt, then must be with relatively low concentration, typically smaller than 3.3mmol/L, otherwise the ammonium salt of high concentration can suppress the growth of microalgae.Can provide nitrogen source with aminoacid for microalgae during microalgae heterotrophism, but aminoacid is expensive, economy is poor.Nitrate is nitrogen source widely used in both culturing microalgae, but finds in practice: the excessive concentration of nitrate can suppress the growth of microalgae.Especially holding concurrently at microalgae luminous energy and support and during chemoheterotrophy, both breeding way are relatively big to the demand in nitrogen source, but add too much nitrate in the medium, can't remarkably promote the growth of microalgae.

Nitrogen oxides (NOx) is one of main atmosphere pollution, not only can produce photochemical fog and acid rain, also result in serious greenhouse effect.The waste gas of industrial discharge is the main source of NOx in air, and therefore the denitration problem of industrial waste gas is increasingly subject to the attention of people.

The method of denitration of industrial waste gas can be divided into dry and wet two kinds.Catalytic reduction method (SCR) and noncatalytic reduction (SNCR) are conventional Dry denitration methods, investment and the operating cost of both approaches are higher, and NOx is reduced into the nitrogen of low value, has been not reaching to the purpose of recycling NOx.Wet denitration is that the NOx in waste gas is absorbed the method being fixed in absorbing liquid, investment and the operating cost of this type of method are low, but need problem of both solution, one is that the NOx in industrial waste gas is mainly NO (typically constituting from more than 90%), and the extremely difficult water that is dissolved in of NO, it is therefore desirable to take steps to solve the solubility of NO；Two is unavoidable generation nitrous acid or nitrite in absorption process, and nitrous acid or nitrite are hypertoxicity materials, it is therefore desirable to take measures to solve to separate or process problem.

At suitable oxidizability (NO₂/ NO mol ratio) under, NOx can be fully absorbed with alkali liquor.CN1768902A discloses " by one or more in hydrogen peroxide, potassium permanganate, sodium chlorite, calcium hypochlorite, chlorine dioxide as oxidant, after being aoxidized by NO, then with alkali liquor absorption ".Research finds, single hydrogenperoxide steam generator oxidation NO effect is unsatisfactory, but uses multiple oxidant to aoxidize NO, necessarily makes liquid absorption element become complicated, it may be difficult to carry out follow-up recycling.

CN 102188891 A discloses a kind of method using concentrated nitric acid, alkali liquor two step to absorb NOx, and the method can aoxidize the NO of 1mol obtain the NO of 3mol by consuming the concentrated nitric acid of 2mol₂, make the oxidizability of NOx improve, then can reach to be completely fixed the effect of NO with alkali liquor.But, if processing the main big capacity industrial waste gas containing NO by the method, not only can consume substantial amounts of nitric acid, and by generating the NOx of nearly 3 times of former content in pilot process, the most also can consume substantial amounts of alkali.It addition, the method can generate substantial amounts of nitrite, how separating, utilize or process these poisonous nitrites becomes a difficult problem.

Existing document shows, in the wet denitration method using hydrogen peroxide/aqueous solution of nitric acid to be absorbing liquid, what effectiveness comparison was good has two kinds, and one is the NOx using the aqueous solution of high concentration nitric acid/low concentration hydrogen peroxide to absorb low degree of oxidation, the method mentioned in such as USP 4341747；Two is to use high-strength hydrogen peroxide/low concentration nitre aqueous acid to absorb the method mentioned in NOx, the such as CN 102407068A of low degree of oxidation.

Existing document shows, low concentration hydrogen peroxide/low concentration nitre aqueous acid is the lowest to the absorbance of low degree of oxidation NOx, therefore be not suitable for processing the main industrial waste gas containing NO, such as " Effect of Temperature on NOx Absorption into Nitric Acid Solutions Containing Hydrogen Peroxide ", Ind.Eng.Chem.Res.1998,37,4418-4423.

A large amount of nitrogen sources consumed are expensive for large-scale cultivation microalgae, if can be combined with industrial waste gas denitration by cultivating microalgae, on the one hand NOx can be utilized to provide nitrogenous fertilizer for micro algae growth, thus reduce the cost of cultivating microalgae；On the other hand can purify again waste gas, the discharge of minimizing NOx, produce more overall situation benefit.Certain references disclose " industrial waste gas is passed directly into both culturing microalgae device and carries out method of denitration ", but all there is following insoluble problem in these methods: 1. utilize microalgae to carry out industrial waste gas denitration and must solve to limit its more business-like problems, such as cultivating microalgae needs illumination and warm weather conditions, and Changes in weather necessarily causes the change of microalgae denitration efficiency, " it is passed directly into industrial waste gas " and will be difficult to mate waste gas discharge operating mode and both culturing microalgae operating mode, two-stage process is caused to interact, it is impossible to meet the reduction of discharging requirement of actual production；2. nitric oxide (NO) is the main component of NOx, and the dissolubility that NO is in water is extremely low, therefore " is passed directly into industrial waste gas " and cannot solve a large amount of NO in NOx water insoluble and be difficult to the problem absorbed.

Generally, photoautotrophic efficiency is less than 30g.m^-2.d^-1, the efficiency of outdoor large-scale culture is generally below 10g.m^-2.d^-1, carry out industrial waste gas denitration with such efficiency and can take substantial amounts of soil, it is therefore necessary to improve the cultivation efficiency of microalgae further.Interpolation organic carbon source carries out Heterotrophic culture or luminous energy is held concurrently and supported the feasible method being to accelerate micro algae growth, but after adding organic carbon source, algae solution is easily polluted by noxious bacteria, causes the growth of antibacterial to be significantly faster than the growth of microalgae, thus causes both culturing microalgae failure.Use the cultivation system closed and carry out strict sterilizing and can realize aseptic condition, but for large-scale farming microalgae, the cost of this method is prohibitively expensive.

Large-scale cultivation microalgae needs substantial amounts of water, if it not being circulated utilization, then can be greatly increased and use water cost.In some cases, it is difficult to breeding water is recycled, such as with slaine as nutrient source time, cyclic culture water can make metal ion accumulate in breeding water body, causes its salinity to be continuously increased, and the generally growth to microalgae of high salinity has obvious inhibitory action.

Summary of the invention

First purpose of the present invention is to improve the cultivation efficiency of microalgae, the cultivation efficiency that particularly raising Heterotrophic culture and luminous energy are held concurrently foster.Sterile working when second object of the present invention is to avoid Heterotrophic culture and luminous energy to hold concurrently foster.Third object of the present invention is organically to be combined with industrial waste gas denitration by both culturing microalgae, and NOx can either be utilized to provide nitrogen source for micro algae growth, is avoided that again that causes because waste gas discharge is different from both culturing microalgae operating mode influences each other.Fourth object of the present invention is, with the aqueous solution of nitric acid/hydrogen peroxide to industrial waste gas denitration, to avoid generating poisonous nitrous acid；Improve the hydrogen peroxide utilization rate of this process simultaneously.

Specifically, the present invention includes herein below.

1. a method for cultivating microalgae, in the culture medium of cultivating microalgae, at least one in nitrogen source, phosphorus source and carbon source provides with the form of alkali metal nutritive salt, it is characterised in that；In breeding process, regulate the pH value of algae solution with nitric acid and/or nitrous acid.

2., according to the method described in 1, it is characterised in that in the culture medium of cultivating microalgae, nitrogen source provides with the form of alkali nitrates and/or alkali metal nitrites salts.

3. according to the method described in 1, it is characterised in that the breeding way of microalgae is that Heterotrophic culture or luminous energy are held concurrently and supported.

4. according to the method described in 3, it is characterised in that the organic carbon source used selected from sugar, organic acid, acylate, alcohol, cellulose hydrolysate and with at least one in glucidtemns；Preferably at least one in glucose, fructose, acetic acid, sodium acetate, lactic acid, ethanol, methanol and cellulose hydrolysate, more preferably glucose.

5. according to the method described in 3, it is characterised in that the concentration of the organic carbon source used controls, in 1g/L algae solution～30g/L algae solution, to be preferably controlled in 2g/L algae solution～10g/L algae solution.

The most in accordance with the method for claim 1, it is characterised in that breeding way is that auto-trophy or luminous energy are held concurrently when supporting, and light intensity is 1000～200000 luxs.

7. according to the method described in 1, it is characterised in that also include isolating microalgae from the algae solution of results, and the foster algae residual liquid obtained after isolating microalgae is cycled to used in the step of cultivating microalgae.

8., according to the method described in 3, it is characterised in that in breeding process, (addition of EM bacterium is 1 × 10 to add EM bacterium in algae solution⁶Individual/L algae solution～9 × 10⁸Individual/L algae solution, preferably 1 × 10⁷Individual/L algae solution～5 × 10⁸Individual/L algae solution).

9. cultivating microalgae and an integrated processes for industrial waste gas denitration, comprises the following steps:

(1) step of cultivating microalgae；In this step, in the culture medium of cultivating microalgae, at least one in nitrogen source, phosphorus source and carbon source provides with the form of alkali metal nutritive salt；

(2) by step that the NOx conversion in industrial waste gas is nitric acid and/or nitrous acid；

(3) with the nitric acid obtained in step (2) and/or nitrous acid, the algae solution pH value of breeding process in regulating step (1).

10., according to the method described in 9, it is characterised in that in the culture medium of step (1), nitrogen source provides with the form of alkali nitrates and/or alkali metal nitrites salts.

11. according to the method described in 9, it is characterised in that the breeding way of step (1) is that Heterotrophic culture or luminous energy are held concurrently and supported.

12. according to the method described in 11, it is characterised in that the organic carbon source used selected from sugar, organic acid, acylate, alcohol, cellulose hydrolysate and with at least one in glucidtemns；Preferably at least one in glucose, fructose, acetic acid, sodium acetate, lactic acid, ethanol, methanol and cellulose hydrolysate, more preferably glucose.

13. according to the method described in 11, it is characterised in that the concentration of the organic carbon source used controls, in 1g/L algae solution～30g/L algae solution, to be preferably controlled in 2g/L algae solution～10g/L algae solution.

14. according to the method described in 9, it is characterised in that the breeding way of step (1) is that auto-trophy or luminous energy are held concurrently when supporting, and light intensity is 1000～200000 luxs.

15. according to the method described in 9, it is characterised in that in the breeding process of step (1), and (addition of EM bacterium is 1 × 10 to add EM bacterium in algae solution⁶Individual/L algae solution～9 × 10⁸Individual/L algae solution, preferably 1 × 10⁷Individual/L algae solution～5 × 10⁸Individual/L algae solution).

16. according to the method described in 9, it is characterised in that in step (2), and using wet denitration is nitric acid by the NOx conversion in industrial waste gas；Absorbing liquid in wet denitration is made up of the nitric acid of 0.5m%～58m%, the hydrogen peroxide of 0.001m%～25m% and excess water.

17. according to the method described in 14, it is characterised in that absorbing liquid is formed by by the nitric acid of 10m%～25m%, the hydrogen peroxide of 0.1m%～1m% and excess water.

The present invention achieves following technique effect.

According to the present invention, during cultivating microalgae, regulate the pH value of algae solution with nitric acid and/or nitrous acid, substantially increase the efficiency of cultivating microalgae.

According to the present invention, both culturing microalgae and industrial waste gas denitration are two relatively independent processes, avoid the influencing each other of causing because waste gas discharge is different from both culturing microalgae operating mode, avoid a large amount of NO water insoluble and be difficult to the problem absorbed, need not extra alkali liquor just can utilize NOx in industrial waste gas to be that microalgae provides nitrogen source, and this makes the method aquaculture cost of the present invention lower.

Present invention, avoiding the accumulation problem of metal ion, make breeding water body be recycled.

According to the present invention, algae solution adds EM bacterium, it is possible to effectively suppress the breeding of noxious bacteria, increase substantially the growth rate of microalgae.This feature makes the present invention when Heterotrophic culture or luminous energy are held concurrently and supported, it is not necessary to carry out disinfection sterilizing, therefore makes the present invention have bigger advantage.

According to the present invention, using low concentration hydrogen peroxide and low concentration nitre aqueous acid to industrial waste gas denitration, the resolution ratio of hydrogen peroxide is lower, effective rate of utilization is the highest.

According to the present invention, while to industrial waste gas denitration, produce dust technology, without poisonous nitrous acid in this dust technology, be more beneficial for being used as the nitrogen source of cultivating microalgae.

Accompanying drawing explanation

Fig. 1 is chlorella growth curve.

Fig. 2 is growth of spirulina platensis curve.

Fig. 3 is embodiment 6～9 and the micro algae growth curve of comparative example 4.

Fig. 4 is the micro algae growth curve of embodiment 10～13.

Detailed description of the invention

The detailed description of the invention of the present invention described further below, it should be noted however that protection scope of the present invention is the most limited to these specific embodiments, but is determined by claims.

Unless otherwise defined, all technology and scientific terminology used by this specification all have the implication that those skilled in the art's routine understands.In case of conflict, it is as the criterion with the definition of this specification.

In the context of the present specification, in addition to the content clearly stated, any matters do not mentioned or item be the most directly suitable for known in the art those and without carrying out any change.And, any embodiment described herein all freely can combine with one or more other embodiments described herein, the technical scheme being consequently formed or technological thought are accordingly to be regarded as the original disclosure of the present invention or a part for original description, and be not considered as the new content the most not disclosing or expecting, unless those skilled in the art think that this combination is the most unreasonable.

All features disclosed in this invention can in any combination, and these combinations should be understood content disclosed in this invention, unless those skilled in the art think that this combination is the most unreasonable.Numerical point disclosed in this specification, not only include specifically disclosed numerical point, also including the end points of each numerical range, the scope of these numerical point institute combination in any is regarded as the scope that the present invention is disclosed or records, no matter the most whether separately disclosing these numerical value pair.

(1) method of cultivating microalgae

A kind of method of cultivating microalgae, in the culture medium of cultivating microalgae, at least one in nitrogen source, phosphorus source and carbon source provides with the form of alkali metal nutritive salt, it is characterised in that；In breeding process, regulate the pH value of algae solution with nitric acid and/or nitrous acid.

According to the present invention, breeding way can be that auto-trophy is (under light illumination, merely with inorganic carbon source such as CO₂Growth), Heterotrophic culture (Heterotrophic culture refer to merely with organic carbon source grow) or luminous energy holds concurrently and supports that (luminous energy is held concurrently to support and referred to, utilizes inorganic carbon source such as CO the most simultaneously₂Grow with organic carbon source).

Micro algae growth needs necessary condition, the most suitable temperature, sufficient illumination (auto-trophy or luminous energy are held concurrently and supported), enough water, CO₂And the nutrient substance such as nitrogenous fertilizer, phosphate fertilizer, dissolved oxygen in regulation and control algae solution, pH value are in the range of suitably etc..Although for different microalgae, these conditions are not quite similar, but these are all known in the art.

It is said that in general, cultivation temperature is 15～40 DEG C, preferably temperature is 25～35 DEG C；Algae solution pH value is 6～11, and preferably algae solution pH value is 7～9.Auto-trophy or luminous energy are held concurrently when supporting, light intensity be 1000～200000 luxs, preferably light intensity be 5000～150000 luxs.

The kind of microalgae is not limited by the present invention.According to the invention it is preferred to cultivate those microalgae being suitable to oil-producing, bioenergy the most both can be obtained, again can be with exhaust gas emission reduction pollutant.

Support can increase part aquaculture cost because using organic carbon source although Heterotrophic culture or luminous energy are held concurrently, but its cultivation efficiency also greatly improves, following process process is made to be simplified, therefore if able to avoid aseptic cultivation, with regard to it can be avoided that consume a large amount of steam system is carried out stringent sterilization process, thus aquaculture cost is greatly reduced.According to the present invention, particularly preferably those can Heterotrophic culture or luminous energy be held concurrently foster microalgae, such as chlorella, scenedesmus, spirulina or single needle algae.Surprisingly, when cultivating these microalgae in the double foster mode of Heterotrophic culture or luminous energy, as long as adding a number of EM bacterium, even if not carrying out disinfection sterilizing, cultivation also can be smoothed out, the growth rate of microalgae greatly speeds up, even if water source contains a large amount of noxious bacteria and/or opens wide cultivation, result is also such；And when being added without EM bacterium, Heterotrophic culture or double the supporting of luminous energy would generally be failed.

Hold concurrently according to the present invention, described Heterotrophic culture or luminous energy in supporting, the most do not carry out disinfecting action, be also added without antibacterial, but add EM bacterium.

Described EM bacterium (Effective Microorganisms) belongs to prior art, it is mainly made up of tens kinds of microorganisms of the thread flora belonging to photosynthetic bacteria group, lactobacillus, yeast flora, Gram positive actinomycetes group, fermentation system, is a kind of commercially available active bacteria formulation.Described EM bacterium both can be prepared according to existing knowledge voluntarily, it is also possible to by commercially available, needs the explanation according to existing knowledge or commercial preparations to ferment before using.

According to the present invention, the consumption of EM bacterium should meet the needs accelerating micro algae growth, can not be very few and inoperative because of consumption, can not consume too much nutrient substance because consumption is excessive with microalgae competition again.The feed postition (such as disposable addition or addition several times) of any EM bacterium and any EM bacterium consumption are all available, as long as the needs accelerating micro algae growth can be met.

According to the present invention, the addition of EM bacterium is preferably 1 × 10⁶Individual/L algae solution～9 × 10⁸Individual/L algae solution；More preferably 1 × 10⁷Individual/L algae solution～5 × 10⁸Individual/L algae solution.

According to the present invention, carrying out Heterotrophic culture or luminous energy is held concurrently when supporting, available organic carbon source includes but not limited at least one in sugar, organic acid, acylate, alcohol, cellulose hydrolysate and glucidtemns；Such as being selected from least one in glucose, fructose, acetic acid, sodium acetate, lactic acid, ethanol, methanol and cellulose hydrolysate, preferably selecting is glucose.

Growth pattern according to micro algae biomass and the Expenditure Levels of culture fluid Middle nutrition material, need to supplement in time not enough nutrient substance.According to the present invention, any mode adding nutrient substance is all available, and such as segmentation is added or added continuously, as long as can the amount of nutrient substance be controlled in the range of suitably.

According to the present invention, carry out Heterotrophic culture or luminous energy is held concurrently when supporting, typically the concentration of organic carbon source is controlled in 1g/L algae solution～30g/L algae solution, be preferably controlled in 2g/L algae solution～10g/L algae solution.Organic carbon source can disposably add, it is also possible to adds several times.

According to the present invention, in described alkali metal nutritive salt, metal ion is sodium and/or potassium.

According to the present invention, described nitrogen source is preferably alkali nitrates and/or alkali metal nitrites salts.

According to the present invention, described phosphorus source is preferably alkali metal phosphate and/or alkali metal hydrogen phosphate.

According to the present invention, a part for described carbon source can be alkali carbonate and/or alkali metal hydrogencarbonate.

According to the present invention, when using auto-trophy, carbon source wholly or largely is with CO₂Form provide.

According to the present invention, described nitrogen source, phosphorus source, the consumption of carbon source are provided by existing known technology, and such as in terms of nitrogen-atoms, the consumption in nitrogen source is 0.1～400mmol/L, preferably 10～300mmol/L, the most preferably 20～200mmol/L.

According to the present invention, also include isolating microalgae from the algae solution of results, and the foster algae residual liquid obtained after isolating microalgae is cycled to used in the step of cultivating microalgae.

(2) cultivating microalgae and the united method of industrial waste gas denitration

A kind of cultivating microalgae and the integrated processes of industrial waste gas denitration, comprise the following steps:

The content of step (1) is identical with the method for aforementioned cultivating microalgae, and the present invention repeats no more.

According to the present invention, the NOx content in industrial waste gas is had no particular limits.It is said that in general, the NOx content in industrial waste gas is at hundreds of ppm (volume) to thousand of ppm, such as between 100ppm to 5000ppm.

According to the present invention, molar fraction >=80% in described industrial waste gas, in terms of the total amount of NOx, shared by NO；Further, molar fraction >=90% in described industrial waste gas, in terms of the total amount of NOx, shared by NO.

According to the present invention, step (2) can use any existing method to be nitric acid and/or nitrous acid by the NOx conversion in industrial waste gas.

Some microalgae can not metabolism NO₂ ^-, when cultivating these microalgae, the method needing to select suitable fixing NOx, so that NOx is largely or entirely converted into NO₃ ^-.According to the present invention, it is known that suitable method is all available, the such as oxidative absorption method with nitric acid/hydrogen peroxide as absorbent.

Can simultaneously metabolism NO according to the invention it is preferred to cultivate those₃ ^-And NO₂ ^-Microalgae, chlorella, single needle algae, scenedesmus or the spirulina that the such as present invention filters out, the most do not exist conversion NO₂ ^-Problem.

According to the present invention, in step (2), it is preferred to use the NOx conversion in industrial waste gas is nitric acid by wet denitration；Absorbing liquid in wet denitration is made up of the nitric acid of 0.5m%～58m%, the hydrogen peroxide of 0.001m%～25m% and excess water.

The present inventor studies discovery, aqueous solution or high-strength hydrogen peroxide/low concentration nitre aqueous acid although with high concentration nitric acid/low concentration hydrogen peroxide, can effectively absorb the NOx of low degree of oxidation, but both approaches all exists hydrogen peroxide and decomposes defect very fast, that loss is bigger.In low concentration hydrogen peroxide/low concentration nitre aqueous acid, the decomposition of hydrogen peroxide is relatively slow, but low concentration hydrogen peroxide/low concentration nitre aqueous acid is the lowest to the absorbing activity of low degree of oxidation NOx.The present inventor has been surprisingly found that through further investigation, although in the starting stage, low concentration hydrogen peroxide/low concentration nitre aqueous acid is the lowest to the absorbing activity of low degree of oxidation NOx, but prolongation over time, the absorbing activity of low degree of oxidation NOx is slowly raised by this aqueous solution, through after a period of time, this aqueous solution enters high-caliber stable phase to the absorbing activity of low degree of oxidation NOx.

According to the present invention, in aforesaid wet denitration, described absorbing liquid is preferably made up of the nitric acid of 10m%～25m%, the hydrogen peroxide of 0.1m%～1m% and excess water；More preferably it is made up of the nitric acid of 10m%～25m%, the hydrogen peroxide of 0.2m%～1m% and excess water.As it was previously stated, the initial denitration activity of the absorbing liquid of this composition is the lowest, it is necessary to through the step of an activation, the requirement to industrial waste gas denitration could be met.This activation step includes: contacted with the gas containing NOx by the solution being made up of with excess water the hydrogen peroxide of the nitric acid of 10m%～25m%, 0.1m%～1m%, when the denitration activity of described solution the most persistently rises, i.e. completes activation step；Molar fraction >=80% in the described gas containing NOx, in terms of the total amount of NOx, shared by NO.The described gas containing NOx for activated absorption liquid, can be described industrial waste gas.

According to the present invention, in aforesaid wet denitration, denitration temperature can be-10 DEG C～40 DEG C, and denitration pressure can be 0.1Mpa～1Mpa；Preferably denitration temperature and pressure is room temperature (10 DEG C～40 DEG C) and normal pressure.

According to the present invention, the way of contact to industrial waste gas in aforementioned wet denitration with active absorption liquid has no particular limits, such as can use one of following (A), (B), (C) or its combine arbitrarily:

(A) industrial waste gas is dispersed in absorbing liquid with bubble shape；

(B) absorbing liquid is dispersed in industrial waste gas with droplet-like；

(C) liquid contacts with industrial waste gas with membranaceous motion.

In the case of You Xuan, use above-mentioned (A) mode.

According to the present invention, in described wet denitration, an absorption tower or the absorption tower of multiple series connection can be used；Preferably employ an absorption tower or the absorption tower of 2～3 series connection.The type on absorption tower is had no particular limits by the present invention, such as can use one of the following or its combine arbitrarily: tray absorption columns, bubble absorbing tower, stirring bubble absorbing tower, by absorbing liquid with droplet-like dispersion spray tower, packed absorber and film-falling absorption tower in the gas phase；Preferably employ bubble absorbing tower or stirring bubble absorbing tower.

In the present invention, described denitration activity refer to process the NOx content of postindustrial waste gas account for process before the molar fraction of NOx content of industrial waste gas.

The present invention is described in detail below by embodiment.

Algae solution optical density value (OD₆₈₀Value) measure: optical density value spectrophotometric determination, compare with distilled water, measure algae solution light absorption value at wavelength 680nm, as the index of microalgae concentration.

The mensuration of solution nitrogen content: use ICS3000 type ion chromatograph (Dionex company of the U.S.) to measure the NO in aqueous solution₃ ^-Content or NO₂ ^-Content, instrument is furnished with EG40 leacheate automatic generator, electric conductivity detector and chameleon chromatographic work station；IonPac AS11-HC type detached dowel (250mm × 4mmi.d.)；IonPac AG11 type guard column (50mm × 4mm i.d.)；Self suppressor of ASRS-ULTRA anion.Leacheate: KOH solution；Flow velocity is 1mL/min；Eluent concentration: 30mmol/L；Sample size is 60 μ L；Column temperature is 30 DEG C；Suppression electric current 100mA；External standard method peak area quantification.

Count of bacteria: carry out count of bacteria according to the following steps

1. sample washing: draw 1ml sample, washs 2-3 time with 1 × PBS；2. initial gross separation: according to algae and the difference of antibacterial centrifugal force, is first centrifuged 2min, initial gross separation algae (, in supernatant, algae is in precipitation for antibacterial) with 1000rpm；If algae content is higher, again repeat；3. collecting supernatant, now the amount of algae in supernatant is negligible, and 8000rpm is centrifuged 5min, abandons supernatant；4. by the 500ul antibacterial resuspended precipitation of rupture of membranes agent, room temperature reaction 15min；5.8000rpm is centrifuged 5min, washs 2 bacterium solution with 1 × PBS；6. add the resuspended thalline of 100ul 1 × PBS, add 5ul PI dye liquor mother solution, room temperature reaction 30min；7. fluorescence microscopy Microscopic observation antibacterial counting, in 4 block plaid, bacterial number is up to 1000, and during more than 1000, dilution bacterium solution certain multiple counts again；8. computing formula:

Bacterial density=count results/4 × extension rate × 4 × 10 in surveyed solution⁴Individual/ml

Main agents consumptive material:

Agents useful for same consumptive material	Manufacturer
		PI Viability Staining Solution	Four positive cypress Cat No.FXP002
Rupture of membranes agent	Sharp that health Cat No.REK3004
		Phosphate buffer (10 × PBS, pH7.4, cell cultivates level, aseptic)	Sharp that health Cat No.REK3013
Cell climbing sheet	NEST

Key instrument:

Instrument	Manufacturer
		Counting chamber	Shanghai precision instrument
Fluorescence microscope	Olympus BX-51

The culture medium of microalgae: medium component is shown in Table 1～table 7.

Table 1 culture medium BG11

Component	Composition, mg/L
		K₂HPO₄·3H₂O	40
NaNO₃	1500
		Na₂CO₃	20

MgSO₄·7H₂O	75
		CaCl₂·2H₂O	36
Citric acid	6
		Ferric ammonium citrate	6
EDETATE SODIUM	1
		Trace element A5 (table 2)	1

Table 2 trace element A5

Component	Composition, mg/L
		H₃BO₃	2860
MnCl₂·4H2O	1810
		ZnSO₄·7H₂O	222
CuSO₄·5H₂O	79
		NaMoO₄·5H₂O	390
Co(NO₃)₂·6H₂O	50

Table 3ZShi culture medium

Component	Composition, g/L
		KH₂PO₄·3H₂O	0.41
NaNO₃	2.5
		NaHCO₃	16.8
NaCl	1.0
		MgSO₄·7H₂O	0.20
K₂SO₄	1.0

CaCl₂·2H₂O	0.04
		FeSO₄·7H₂O	0.01
EDETATE SODIUM	0.08
		Trace element A5 (table 4)	1ml
Trace element A6 (table 5)	1ml

Table 4 trace element A5

Component	Composition, g/L
		H₃BO₃	2.86
MnCl₂·4H₂O	1.8
		ZnSO₄·7H₂O	0.22
CuSO₄·5H2O	0.08
		MoO₃	0.01

Table 5 trace element A6

Component	Composition, mg/L
		NH₄VO₃	22.9
NiSO₃·7H₂O	47.8
		Ti₂(SO₄)₃	40
NaWO₄	17.9
		Co(NO₃)₂·6H₂O	4.4

Table 6 Heterotrophic culture base

Table 7 trace element

Component	Composition, g/L
		H₃BO₃	2.86
MnCl₂·4H₂O	0.11
		ZnSO₄·7H₂O	9.22
CuSO₄·5H₂O	1.00
		(NH₄)₆Mo₇O₂₄·4H₂O	0.10
Co(NO₃)₂·6H₂O	0.90

EM bacterium: probiotic bacteria used in embodiment be Kang Yuan oasis bio tech ltd produce such as gold probiotic bacteria, carry out activation process, PH < 4 by its explanation before using.

Comparative example 1

This comparative example is used for explanation low concentration NH₄HCO₃Cultivate the effect of chlorella.

Use BG11 culture medium (table 1 and 2) to cultivate chlorella (Chinese Academy of Sciences's aquatile institute provides), change the nitrogen source in BG11 culture medium into NH₄HCO₃, nitrogen concentration is 3.3mmol/L, and this nitrogen concentration is far below the nitrogen concentration (17.6mmol/L) in BG11 culture medium.Algae kind initial concentration OD₆₈₀Being 0.5, be passed through compressed air and cultivate, controlling temperature is between 20～30 DEG C.Using natural daylight to cultivate in incubation, daylight intensity reaches as high as 60000lux.Its growth curve is shown in Fig. 1.

Comparative example 2

This comparative example is used for explanation low concentration NaNO₃Cultivate the effect of chlorella.

With the difference is that only of comparative example 1: change the nitrogen source in culture medium into NaNO₃.Detect the OD of algae solution every day₆₈₀Value, its growth curve is shown in Fig. 1.

Comparative example 3

This comparative example is used for illustrating by high concentration NaNO₃Cultivate the effect of chlorella.

It is with the difference of comparative example 1: change the nitrogen source in culture medium into NaNO₃, nitrogen concentration increases to 176mmol/L, and this nitrogen concentration is far above the nitrogen concentration (17.6mmol/L) in BG11 culture medium.Detect the OD of algae solution every day₆₈₀Value, its growth curve is shown in Fig. 1.

Embodiment 1

The present embodiment is for illustrating the present invention effect when autotrophy cultivates chlorella.

The present embodiment the difference is that only with comparative example 1: nitrogen source and concentration thereof still use the formula of BG11 culture medium, and late stage of culture, when pH value is higher than 10, is supplemented nitric acid and adjusted in the range of suitably by pH, detect the OD of algae solution every day₆₈₀Value, its growth curve is shown in Fig. 1.

Embodiment 2

The present embodiment is for illustrating the present invention effect when autotrophy cultivates spirulina.

Use ZShi culture medium (table 3,4 and 5) cultivating spirulina (Chinese Academy of Sciences's aquatile institute provides), algae kind initial concentration OD₆₈₀Being 0.3, be passed through compressed air and cultivate, controlling temperature is between 20～30 DEG C, when pH value is higher than 10.5, supplements nitric acid and is adjusted in the range of suitably by pH.Using natural daylight to cultivate in incubation, daylight intensity reaches as high as 60000lux.Detect the OD of algae solution every day₆₈₀Value, its growth curve is shown in Fig. 2.

Embodiment 3

The present embodiment is for illustrating the present invention effect (not carrying out disinfecting action) when mixotrophic cultivation chlorella.

The present embodiment the difference is that only with same comparative example 1: uses chlorella heterotrophy culture medium (table 6 and 7), within in incubation every three days, add 2g/L glucose and 0.5ml/L fermented-EM bacterium solution, when pH value is higher than 10, supplements nitric acid and pH is adjusted in the range of suitably.Detect the OD of algae solution every day₆₈₀Value, its growth curve is shown in Fig. 1.

Embodiment 4

The present embodiment is for illustrating the present invention effect (not carrying out disinfecting action) when mixotrophic cultivation spirulina.

The present embodiment the difference is that only with embodiment 2: in incubation, within every three days, adds 2g/L glucose and 0.5ml/L fermented-EM bacterium solution, when pH value is higher than 10.5, supplements nitric acid and is adjusted in the range of suitably by pH.Detect the OD of algae solution every day₆₈₀Value, its growth curve is shown in Fig. 2.

Embodiment 5

The present embodiment is for illustrating the present invention effect when aseptic Heterotrophic Mass Cultures of Chlorella.

Chlorella is identical with comparative example 1, uses chlorella heterotrophy culture medium (table 6 and 7) to carry out Heterotrophic culture, algae kind initial concentration OD₆₈₀Being 0.5, be passed through compressed air, cultivate under aseptic, no light condition, controlling temperature is between 20～30 DEG C.When glucose consumption totally time add glucose 10g/L in time；When pH value is higher than 10, supplements nitric acid and pH is adjusted in the range of suitably.Detect the OD of algae solution every day₆₈₀Value, its growth curve is shown in Fig. 1.

From Fig. 1～2, the method using the present invention, the growth efficiency of microalgae can be improved.If adding nitrate in a large number at the cultivation initial stage, then high concentration nitrate can't remarkably promote the growth of microalgae.

Embodiment 6～13 is used for " in the case of a large amount of interpolation organic carbon sources, the impact that EM bacterium is inorganic nitrogen-sourced on microalgae metabolism " are described.

Embodiment 6

Chlorella (from Sinopec microalgae algae kind storehouse, numbering Chlorella sp.RIPP-1) is cultivated initially with BG11 culture medium (adding nutritional labeling by table 1,2, culture fluid does not carry out sterilization treatment)；Work as OD₆₈₀When value is 4, add a Heterotrophic culture base nutritional labeling by table 3 ormal weight.Controlling temperature is between 20～30 DEG C, is passed through compressed air and CO₂Cultivate, when algae solution PH > 10 time be passed through CO₂, when algae solution PH < stops when 7.5 being passed through CO₂.Using natural daylight to cultivate in incubation, daylight intensity reaches as high as 60000 luxs, adds the glucose of 2g/L, and by 2.9 × 10⁷The amount of individual/L algae solution adds EM bacterium, detects the OD of algae solution every day₆₈₀Value；The glucose of 10g/L is again added after cultivating 1 day, and by 3.6 × 10⁷Individual/L algae solution adds EM bacterium；Again adding glucose 10g/L when cultivating to the 5th day, the count of bacteria monitoring algae solution in breeding process is up to 9.7 × 10⁶Individual/mL algae solution, gathers in the crops after cultivating 8 days continuously, stops being passed through CO after last addition glucose₂, terminating algae solution pH value during cultivation is 8.6, is centrifugally separating to obtain algae mud and foster algae residual liquid.Analyze the NO supported in algae residual liquid₃ ^-With NO₂ ^-Total content < 10 μ g/g.The growth curve of microalgae is shown in Fig. 3.

Embodiment 7

The present embodiment differs only in embodiment 6: cultivating microalgae is single needle algae (from Sinopec microalgae algae kind storehouse, numbering Monoraphidium dybowskii.RIPP-50).The count of bacteria monitoring algae solution in breeding process has been up to 4.6 × 10⁷Individual/mL algae solution, at the end of recording cultivation, the pH of algae solution is increased to 8.2 naturally, analyzes the NO supported in algae residual liquid₃ ^-With NO₂ ^-Total content < 200 μ g/g.The growth curve of microalgae is shown in Fig. 3.

Embodiment 8

The present embodiment differs only in following aspect with embodiment 6: primary EM bacterium addition is 7.9 × 10⁷Individual/L algae solution, without secondary EM bacterium；And the glucose amount that second time is added is 30g/L, without third time glucose.The count of bacteria monitoring algae solution in breeding process is up to 2.6 × 10⁷Individual/mL algae solution, at the end of recording cultivation, the pH of algae solution is increased to 8.2 naturally, analyzes the NO supported in algae residual liquid₃ ^-With NO₂ ^-Total content < 10 μ g/g.The growth curve of microalgae is shown in Fig. 3.

Embodiment 9

The present embodiment differs only in embodiment 8: cultivating microalgae is single needle algae (from Sinopec microalgae algae kind storehouse, numbering Monoraphidium dybowskii.RIPP-50).The count of bacteria monitoring algae solution in breeding process has been up to 5.2 × 10⁷Individual/mL algae solution, at the end of recording cultivation, the pH of algae solution is increased to 7.8 naturally, analyzes the NO supported in algae residual liquid₃ ^-With NO₂ ^-Total content < 200 μ g/g.The growth curve of microalgae is shown in Fig. 3.

Comparative example 4

This comparative example differs only in embodiment 6: without EM bacterium.In monitoring incubation, algae solution count of bacteria is up to 13.6 × 10⁸Individual/mL algae solution, at the end of recording cultivation, the pH of algae solution is increased to 7.2 naturally.The growth curve of microalgae is shown in Fig. 3.

As can be seen from Fig. 3, add EM bacterium the growth of microalgae is greatly facilitated and consumes rapidly inorganic nitrogen-sourced.

Embodiment 10

Chlorella is cultivated initially with BG11 culture medium (adding nutritional labeling by table 1,2, culture fluid does not carry out sterilization treatment)；Work as OD₆₈₀When value is 4, add a Heterotrophic culture base nutritional labeling by table 3 ormal weight.Controlling temperature is between 20～30 DEG C, is passed through compressed air and CO₂Cultivate, when algae solution PH > 10 time be passed through CO₂, when algae solution PH < stops when 7.5 being passed through CO₂.Using natural daylight to cultivate in incubation, daylight intensity reaches as high as 60000 luxs, first cultivating 2 days under illumination autotrophic condition after chlorella inoculation, then adds the glucose of 2g/L, and by 1.8 × 10⁸The amount of individual/L algae solution adds EM bacterium, detects the OD of algae solution every day₆₈₀Value；The glucose of 10g/L is again added after cultivating 3 days, and by 1.8 × 10⁸Individual/L algae solution adds EM bacterium；Again adding glucose 10g/L after cultivating 2 days, the count of bacteria monitoring algae solution in breeding process is up to 2.9 × 10⁷Individual/mL algae solution, gathers in the crops after cultivating 14 days continuously, stops being passed through CO after last addition glucose₂, terminating algae solution pH value during cultivation is 9.2, is centrifugally separating to obtain algae mud and foster algae residual liquid.Analyze the NO supported in algae residual liquid₃ ^-With NO₂ ^-Total content < 10 μ g/g.The growth curve of microalgae is shown in Fig. 4.

Embodiment 11

The present embodiment differs only in following aspect with embodiment 10: without secondary EM bacterium；And the glucose amount that second time is added is 30g/L, without third time glucose.The count of bacteria monitoring algae solution in breeding process is up to 2.9 × 10⁷Individual/mL algae solution, at the end of recording cultivation, the pH of algae solution is increased to 9.3 naturally, analyzes the NO supported in algae residual liquid₃ ^-With NO₂ ^-Total content < 10 μ g/g.The growth curve of microalgae is shown in Fig. 4.

Embodiment 12

The present embodiment differs only in embodiment 10: NaNO in BG11 culture medium₃Replace with KNO₃, and KNO₃Addition is 0.5g/L.The count of bacteria monitoring algae solution in breeding process is up to 1.3 × 10⁷Individual/mL algae solution, recording the pH value of algae solution when terminating cultivation is 9.4, analyzes the NO supported in algae residual liquid₃ ^-With NO₂ ^-Total content < 10 μ g/g.The growth curve of microalgae is shown in Fig. 4.

Embodiment 13

The present embodiment differs only in embodiment 11: the NaNO in BG11 culture medium₃Replace with KNO₃, and KNO₃Addition is 0.5g/L.The count of bacteria monitoring algae solution in breeding process is up to 1.7 × 10⁷Individual/mL algae solution, recording the pH value of algae solution when terminating cultivation is 9.3, analyzes and supports algae residual liquid

In NO₃ ^-With NO₂ ^-Total content < 10 μ g/g.The growth curve of microalgae is shown in Fig. 4.

As can be seen from Fig. 4, using potassium nitrate or sodium nitrate as nitrogen source, add EM bacterium and all promote the growth of microalgae.

Embodiment 14

The present embodiment is used for nitric acid or H are described₂O₂The concentration change impact on hydrogen peroxide decomposition rate.

Nitric acid/the H of preparation variable concentrations₂O₂Aqueous solution, measures H after 10 days₂O₂Concentration, calculate variable concentrations nitric acid/H₂O₂H in aqueous solution₂O₂Resolution ratio, result of calculation is shown in Table 8.(measuring concentration of hydrogen peroxide by the method for GB1616-2003)

Table 8

Table 8 is visible, no matter improving concentration of nitric acid, or improves concentration of hydrogen peroxide, and the loss resulting in hydrogen peroxide dramatically increases.

Embodiment 15

The present embodiment is for illustrating the present invention denitration effect to low concentration of NO x.

Simulated exhaust NO, NO₂Preparing with nitrogen, the concentration of NO is 500ppm (volume), NO₂Concentration be 20ppm (volume).Absorbing liquid is made up of the nitric acid of 15m%, the hydrogen peroxide of 0.4m% and excess water.Absorption plant uses glass tower, a diameter of 100mm of glass tower, a height of 700mm；Being provided with sieve plate in the bottom of glass tower, hole diameter of sieve (perforated) plate is 16 μm～30 μm；Tower is built with 3000ml absorbing liquid；The flow velocity of simulated exhaust is 150L/h；Test is carried out under room temperature, normal pressure.Result of the test is shown in Table 9.(measuring by the method for GB/T14642-2009, find in the absorbing liquid after test without nitrite anions)

Table 9

Table 9 is visible, and in the denitration starting stage, the denitration activity of absorbing liquid is the lowest, increases in time, and absorbing liquid denitration activity slowly continues to increase, and after 16 hours, the denitration activity of absorbing liquid enters stable phase, and denitration rate now reaches more than 90%.

Embodiment 16

The present embodiment the difference is that only with embodiment 15: the concentration of hydrogen peroxide is 1m%, and the concentration of nitric acid is 25m%.Result of the test is shown in Table 10.(measuring by the method for GB/T14642-2009, find in the absorbing liquid after test without nitrite anions)

Table 10

Time/h	1	2	4	8	12	16	20
								Outlet NO/ppm	430	400	330	220	100	36	27
Outlet NO₂/ppm	0	0	0	0	0	2	11
								Outlet NOx/ppm	430	400	330	220	100	38	38

Embodiment 17

The present embodiment is used for illustrating, denitration effect to high concentrate NOx when the present invention uses single column.

The present embodiment the difference is that only with embodiment 15: the concentration of hydrogen peroxide is 0.3m%, and the concentration of nitric acid is 15m%；In simulated exhaust, the concentration of NO is 3200ppm (volume), NO₂Concentration be 100ppm (volume).Result of the test is shown in Table 11.(measuring by the method for GB/T14642-2009, find in the absorbing liquid after test without nitrite anions)

Table 11

Time/h	1	2	4	8	12	16	20	24	30	35	40	45
													Outlet NO/ppm	2310	1900	1600	1400	1300	1250	1200	1000	830	750	800	830
Outlet NO₂/ppm	60	50	35	35	30	30	50	120	290	320	290	260
													Outlet NOx/ppm	2370	1950	1635	1435	1330	1280	1250	1120	1110	1070	1090	1090

Embodiment 18

The present embodiment is used for illustrating to use high concentration H₂O₂Time denitration effect.

The present embodiment the difference is that only with embodiment 15: the concentration of hydrogen peroxide is 2.5m%, and the concentration of nitric acid is 15m%.Result of the test is shown in Table 12.

Table 12

Time/h	1	2	4	8	12	16	20
								NO/ppm	59	20	50	30	25	25	35
NO₂/ppm	14	25	15	20	20	15	10
								NOx/ppm	73	45	75	50	45	40	35

Embodiment 19

Denitration effect when this comparative example is for illustrating to use high concentration nitric acid.

This comparative example the difference is that only with embodiment 15: the concentration of hydrogen peroxide is 0.4m%, and the concentration of nitric acid is 35m%.Result of the test is shown in Table 13.Measure by the method for GB/T14642-2009, find in the absorbing liquid after test without nitrite anions.

Table 13

Time/h	1	2	4	8	12	16	20
								NO/ppm	57	6	11	9	9	10	11
NO₂/ppm	30	43	37	32	32	33	32
								NOx/ppm	87	49	48	41	41	43	43

Claims

1. a method for cultivating microalgae, in the culture medium of cultivating microalgae, in nitrogen source, phosphorus source and carbon source At least one provide with the form of alkali metal nutritive salt；It is characterized in that, in breeding process, use nitre Acid and/or the pH value of nitrous acid regulation algae solution.

The most in accordance with the method for claim 1, it is characterised in that the culture medium of described cultivating microalgae In, nitrogen source provides with the form of alkali nitrates and/or alkali metal nitrites salts.

The most in accordance with the method for claim 1, it is characterised in that the breeding way of microalgae is heterotrophism Cultivate or luminous energy is held concurrently and supported.

The most in accordance with the method for claim 3, it is characterised in that the organic carbon source used is selected from Sugar, organic acid, acylate, alcohol, cellulose hydrolysate and with at least one in glucidtemns.

The most in accordance with the method for claim 3, it is characterised in that the organic carbon source used dense Degree controls in 1g/L algae solution～30g/L algae solution.

The most in accordance with the method for claim 1, it is characterised in that breeding way be auto-trophy or Luminous energy is held concurrently when supporting, and light intensity is 1000～200000 luxs.

The most in accordance with the method for claim 1, it is characterised in that also include from the algae solution of results Isolate microalgae, and the foster algae residual liquid obtained after isolating microalgae is cycled to used in the step of cultivating microalgae.

The most in accordance with the method for claim 3, it is characterised in that in breeding process, in algae solution Add EM bacterium.

(1) step of cultivating microalgae；In this step, in the culture medium of cultivating microalgae, nitrogen source, phosphorus source There is provided with the form of alkali metal nutritive salt with at least one in carbon source；

(3) with cultivation in the nitric acid obtained in step (2) and/or nitrous acid, regulating step (1) The algae solution pH value of process.

The most in accordance with the method for claim 9, it is characterised in that the cultivation of described step (1) In base, nitrogen source provides with the form of alkali nitrates and/or alkali metal nitrites salts.

11. in accordance with the method for claim 9, it is characterised in that the breeding way of step (1) Hold concurrently for Heterotrophic culture or luminous energy and support.

12. in accordance with the method for claim 11, it is characterised in that the organic carbon source choosing used From sugar, organic acid, acylate, alcohol, cellulose hydrolysate and with at least in glucidtemns Kind.

13. in accordance with the method for claim 11, it is characterised in that the organic carbon source used Concentration controls in 1g/L algae solution～30g/L algae solution.

14. in accordance with the method for claim 9, it is characterised in that the breeding way of step (1) When holding concurrently foster for auto-trophy or luminous energy, light intensity is 1000～200000 luxs.

15. in accordance with the method for claim 9, it is characterised in that the breeding process of step (1) In, in algae solution, add EM bacterium.

16. in accordance with the method for claim 9, it is characterised in that in step (2), uses wet NOx conversion in industrial waste gas is nitric acid by method denitration；Absorbing liquid in wet denitration by 0.5m%～ The nitric acid of 58m%, the hydrogen peroxide of 0.001m%～25m% and excess water composition.

17. in accordance with the method for claim 14, it is characterised in that absorbing liquid is by by 10m%～25m% Nitric acid, the hydrogen peroxide of 0.1m%～1m% and excess water composition.