Preparation And Properties Of Waterborne Polymeric Dust Suppressant

The contribution of road dust to ambient suspended particulates content is as high as20%.Long-term exposure to this environment can lead to cardiovascular and respiratory system damage.Compared with watering dust suppression,waterborne polymer can improve the capture efficiency of droplets on particles by wetting.The cohesion and particle size can be increased through coagulation and adhesion process among dust,and therefore the dust concentration will be reduced.In this paper,the VAc copolymer emulsion was prepared as the dust suppressor.The wettability and stabilization of emulsion to simulated PM₁₀0 suspended particulates were discussed,and the aggregation and inhibition effect of the copolymer on particulates were analysed through the stabilization of the emulsion to road floating dust.Vinyl acetate（VAc）,butyl acrylate（BA）,acrylic acid（AA）,and hydroxyethyl acrylate（HEA）copolymer emulsion was prepared through semi-continuous feeding process.The influences of emulsifier,AA,HEA and feeding method on latex diameter and emulsion wettability were discussed.It indicated that ionic and non-ionic emulsifier might obtain a positive synergic wettability,and the latex size decreased with the increasing of emulsifier concentration.When AA dosage was 5.0wt%,the average latex size increased to 231 nm.The wettability of emulsion to simulated dust increased along with the increasing acrylic acid dosage and the neutralization degree.When 3.0wt%AA was feeded to polymerization and the neutralization degree was 90%,the contact angle of emulsion on the dust decreased to 37.2°,and the adhesion force was 5.91 nN.The particle size of latex was basically unchanged 0.2wt%¹.5wt%HEA was feeded to polymerization.When HEA was evenly feeded to polymerization with other monomers,it would obtain the ionicity-nonionicity balance on emulsion particle surface,and therefore,the wettability to simulated dust was improved.Based on consolidation morphology,pore structure,and compressive strength of simulated dust,the influence of the emulsion on the interparticle adhesion was investigated.When the concentration of emulsion was 3.0wt%,the adsorption of the polymer on the simulated dust reached to 62.82%.In the same condition,the Shore D hardness of consolidated dust was up to 44.The SEM results showed that the interface between the particles was clear and the dust was packed loosely as a result of water’s poor wettability.On the contrary,the wettability of the emulsion to the dust was improved,in which morphology particle-to-particle stacked densely and blurred interface between aggregates were observed.Simulated dust with water had high porosities,and the cumulative pore volume was 0.0352 cm³/g.As a result,the compressive strength was only 0.63 MPa.While the pore volume decreased to 0.0123 cm³/g of the dust in consolidation,and the compressive strength was 3.52 MPa.The stabilization results of the copolymer emulsion to road floating dust showed that the compressive strength of floating dust was 8.27 MPa for curring 28 days,in which morphology particle-to-particle stacked densely was observed.Wind tunnel test showed the mass loss of road dust was only 1.92wt%,under eight wind conditions.While the blank dust particles were loosely distributed with more pores.The compressive strength was only1.04 MPa,and the wind erosion loss reached to 51.9wt%in the same condition.According to the urban dust suppression test results,the polymeric dust suppressant reduced the PM_2.5concentration by 22.0%,and the PM₁₀0 decreased 27.7%.