Preparation Of Polymer Microspheres And Study On The Effectiveness And Mechanism Of Fog Suppression

Acid mist is an urgent need to address important issues in the field of environmental protection.It was generated in electrowinning,electroplating,pickling and rust removal processes.As part of these processes,large volumes of oxygen and hydrogen gases in the form of micro-bubbles are generated at the electrodes because of displacement or electrochemical reaction.The burst of these bubbles at the free surface of the acid solution ejects fine acid-containing droplets into the air and froming acid mist.The acid mist poses a serious health hazard to the workers but also accelerates the corrosions of the factory equipments and aggravate air pollution.So how to suppress acid mist became an environmental protection.The main strategies to suppress acid mist included ball covering,bubble covering and adding surfactants.In this thesis,the crosslinking and non-crosslinking polystyrene microspheres were prepared as a new type of acid mist inhibitor suppressant,They have the characteristics of being resistance to strong acid,low density,no penetration and long floating time;in addition,the gap between the microspheres can be adjusted,the bubbles(d=20-400?m)and acid mist droplets(d=10-200?m)can be suppressed by one or several layers of microspheres.In the meanwhile,the microspheres layers do not affect the discharge of hydrogen and oxygen,at the same time.The performance of the polystyrene microspheres as acid mist suppressants was evaluated by using a self-made acid mist generated simulation device and acid mist testing device.Polystyrene microspheres with adjustable particle size and density were prepared as a function of stirring speed,the amount of dispersant,oil/water ratio,dispersant added time,the dosage of initiator and the dosage of porogen.Their particle size distribution,average particle size,density and micro structure were characterized.The main research results are as follows:1?By controlling the stirring speed,the amount of dispersant,oil/water ratio,we can prepare non-crosslinked and solid polystyrene microspheres of particle size between 200 and 2500?m.By controlling the addition time of the dispersant,non-crosslinked and solid polystyrene microspheres with a wide particle size distribution which was 200 and 4000?m can be prepared.2?The dosage of porogen have deep effects on the particle size and density of the crosslinked polystyrene microspheres of under certain stiring speed and concentration of dispersant.The crosslinked polystyrene microspheres with a low density of 0.89-1.04 g/cm3 and particle size of 200 to 2500?m were prepared.3.The acid mist suppression performance of polystyrene microspheres is closely related to the thickness of the microsphere layer and the ratio of their particle size.When the thickness of the layer is thicker and denser,acid mist suppression effect is better.The larger the particle size,the better the gas discharged;small bubbles or small acid droplets escaped from the gaps of microspheres,acid mist suppression effect is poor.The smaller the particle size,the narrower the gap between microspheres;bubbles are easy to aggregate and form large bubbles which is negative for gas discharging.By adjusting the thickness of microsphere layer,the ratio of particle size and their density,an optimum acid mist suppression effect can be achieved.