Study On Preparation And Application Of A Novel Biological Dust Suppressant

With the rapid development of my country’s economy and the significant improvement of people’s living standards,people are paying more attention to environmental quality.In recent years,air pollution in northern cities in my country has been particularly severe,mainly reflected in the increase in smog and dust days.The dust particles are the main component of smog.So far,the main method of suppressing dust is spraying chemical dust suppressants,but chemical dust suppressants have secondary pollution,corrosion,and damage to soil and plants.γ-PGA is a polymer biomaterial that can be produced by microbial fermentation and has moisture retention,viscosity,film-forming properties,degradability and environmental compatibility.It has the characteristics of being a dust suppressant and is expected to be used as a new type of safety Environmentally friendly biological dust suppressant,applied to urban public spaces with dense crowds and public facilities.Therefore,the research of γ-PGA as a dust suppressant will provide new ideas for the development of eco-friendly dust suppressants.In this study,a high-yield γ-PGA strain was selected from the biogas slurry.The fermentation conditions were optimized through single factor test and response surface method,and the fermentation product γ-PGA was used as a new type of biological dust suppressant.Under simulated conditions,γ-PGA was sprayed on the road dust.After spraying,the moisturizing performance,permeability,evaporation resistance,wind resistance index,consolidation ability and dust suppression rate of the dust were studied,and γ-PGA was used as an environmentally friendly dust suppression Agents provide a theoretical basis.The main conclusions are as follows:1.A γ-PGA high-yielding strain LW-1 was screened out,and it was determined to be Bacillus siamese through routine identification and molecular biological identification;basic fermentation experiments revealed that it was a glutamateindependent strain,but added glutamine Acid will greatly increase the yield of γ-PGA;the crude γ-PGA extract is prepared by shaking flask fermentation and organic solventprecipitation,and the content of γ-PGA in the crude extract is 63.28%.2.Optimize the fermentation conditions for y-polyglutamic acid production by Bacillus siamese LW-1 through single factor experiment and response surface methodology:the optimal fermentation medium components are sodium glutamate 86.71g/L and sodium citrate 17.94 g/L,MgSO4·7H2O 2.11g/L,glycerol 25 g/L,KH2PO4 1.4 g/L,(NH4)2SO4 14 g/L,MnSO4 0.075g/L,CaCl2 0.1 g/L,FeCl3·6H2O 0.04 g/L 0.04g/L;The most suitable culture conditions are temperature 37℃,initial pH 7.5,inoculation amount 2%,filling volume 60mL/250mL,shaker rotation speed is 210r/min,the yield reaches the maximum at 63h of fermentation,the yield of γ-PGA is 45.24g/L,compared with 23.26g/L before optimization,the yield increased by 1.94 times.3.The physical and chemical properties of the produced γ-PGA:The crude γ-PGA extract is weakly acidic in the aqueous solution and is not very corrosive to the pavement;γ-PGA has a certain stability to high temperatures and starts to decompose at 300℃.4.Research on the application performance of the produced γ-PGA as a dust suppressant:a.Water retention.The higher the content of γ-PGA,the better the moisture retention.At 25℃,after 8 hours,the water content of 0.1%γ-PGA It is 46.52%;however,as the temperature increases,the moisture retention performance ofγ-PGA becomes worse,and the effective duration of dust suppression becomes shorter;γ-PGA can significantly slow down the evaporation of water in dust.b.Permeability,the permeability of 0.01%～0.3%γ-PGA is not much different from that of water,and the permeability becomes worse when it is greater than 0.5%.c.Evaporation resistance.The higher the concentration of γ-PGA,the stronger the ability to resist evaporation;with the increase of temperature,the evaporation resistance of γ-PGA becomes worse.d.Wind resistance index,the concentration of γ-PGA to reach the optimal wind resistance index 63.83 is 0.3%,and the wind resistance index is 60.12 at a concentration of 0.1%.e.Consolidation ability.With the increase of concentration,the stronger the consolidation ability of γ-PGA on sandy soil.f.Dust suppression rate.The dust suppression rate increases with the increase of γ-PGA concentration and decreases with time;the dust suppression rate of γ-PGA in the concentration range of 0.1%to 1%remains basically stable after the 12th day.In summary,tThe yield of γ-PGA of Bacillus siamese LW-1 under the optimized fermentation conditions was 45.24 g/L.The higher the concentration of γ-PGA,the better its moisture retention,anti-evaporation,consolidation ability and dust suppression effect;combined with experimental data,use cost,spraying convenience,spraying device factors,when γ-PGA is applied to urban roads For road dust suppression,it is recommended to choose γ-PGA with a concentration of 0.1%;when it is applied to consolidated sand soil,γ-PGA with a concentration greater than 0.5%can be selected.