Preparation And Performance Of A Composite Dust Suppressant Using Greening Wastes As Raw Material

The atmospheric dust caused by construction activities is an important source of PM_2.5and PM₁₀in the air,which not only causes environmental pollution,but also seriously affects the health of people.At present,the main measures to deal with construction dust include sprinkling water,green net covering and dust-suppressor spraying.Among them,dust-suppressant spraying has attracted extensive attention in recent years because of its high dust-suppressant efficiency and no residual solid waste.In this study,cellulose was extracted from sycamore branches and used to prepare carboxymethyl cellulose sodium.A composite dust suppressant was prepared by using film-forming polyvinyl alcohol and wettability surfactant as composite additives.Firstly,the sycamore branches before and after the pretreatment with deep-eutectic solvents,the extracted products and the reaction products,were identified and characterized by FTIR and XRD,the apparent morphology was observed,and the optimal pretreatment conditions were initially explored.Then the component content characteristics of the composite dust suppressant were investigated by single factor experiment.In addition based on orthogonal experiment and TOPSIS analysis,the optimal ratio of the dust suppressant was obtained.Nextly,The self-made dust suppressant,three kinds of dust suppressants and pure water were tested and compared on the basic physical and chemical properties and application performance,and the microscopic morphology and structure of the composite dust suppressant and dust were characterized.The main results are as follows:（1）With the weight loss rate of wood powder as the index,the optimal pretreatment solvent of wood powder was choline-ethylene glycol chloride.The optimal reaction time,reaction temperature and mass liquid-solid ratio were 6 h,160℃,and 20:1,respectively.The wood powder was treated with choline chloride and ethylene glycol,then extracted by nitricacid-ethanol method,and finally obtained by alkaline etherification reaction,the extracted products and reaction products,through FTIR and XRD characterization,the results showed that cellulose was successfully extracted,and the product obtained by reaction was CMC.（2）The best surfactant was octyl-decyl glucoside（APG0810）by monomer test.The composite dust suppressant was obtained by mixing the prepared CMC with PVA and APG0810.The results of single factor experiment show that the higher the mass fraction of CMC and PVA,the higher the viscosity of the composite dust inhibitor.The mass fraction of APG0810 had no obvious effect on the viscosity of the composite dust suppressant.The sedimentation time and contact Angle increase with the increase of mass fraction of CMC and PVA.APG0810 is a surfactant.The larger the mass fraction,the smaller the contact Angle and settling time,and the better the wettability of the composite dust suppressant.The higher the mass fraction of the three components,the better the wind erosion resistance of the dust suppressant.The more the content of surfactant,the more the biotoxicity of dust suppressant.（3）Orthogonal experimental results showed that CMC content had a significant effect on the adhesion and wettability of the composite dust suppressant.The content of PVA had a significant effect on adhesion and wind erosion resistance.The content of APG0810 was a significant factor affecting wettability and biotoxicity.The orthogonal experiment and TOPSIS method were used to analyze the comprehensive performance of the composite dust suppressant,the results showed that the mass fractions of CMC,PVA and APG0810 in the optimal formula were 0.20%,2.00%and 0.10%.The viscosity of the dust suppressant prepared with this ratio at 25℃was 41.97 mpa·s,the settling time was 68.62 s,the mass loss rate was 0.57%,and the germination rate of wheat was70%,which showed good comprehensive performance.（4）The self-made dust suppressant has a p H of 7.4,a solid content of 1.09%,and a density of 1.0518 g/cm³.When the spraying volume is 3.45 L/m²,the curing layer thickness is 11.56 mm,which all meet the requirements of the industry standard.Compared with the commercial dust suppressant and pure water,it is found that the self-made dust suppressant has good adhesion,wettability,wind erosion resistance and not obvious biological toxicity.After SEM characterization of the dust before and after spraying,it was found that the scattered fine particles on the surface of the original soil sample were cohesive and agglomerated.After FTIR and XRD characterization,it was found that the soil structure before and after spraying the dust suppressant had almost no obvious change.