Simulation Experiment of Microplastics Removal in Waste Plastic Regeneration Effluent

Abstract

Microplastics are emerging pollutants that can be founded in different environments.Microplastics mainly come from waste plastic products,they have a wide range of pollution and potential environmental pollution problems.The concentration of microplastics in wastewater from waste plastic recycling enterprises is much higher than that of other types of sewage.Hence,it is of great environmental significance to treat microplastics in the wastewater of waste plastics recycling enterprises.By simulating the production of wastewater from waste plastics recycling enterprises and flocculation precipitation,this study explored the influence of several factors that affect the removal rate of microplastics in wastewater including flocculant dosage,pH value,hydraulic stirring single factor and orthogonal experiment.The results showed that:(1)When the dosage of PAC was 10 mL,PAM was 7 mL and pH was 9,the stirring was divided into two stages,the first stage was stirred at 100 r /min for 40 s and the second stage was stirred at 200 r min for 40 s,the total removal of microplastics could reach the highest value of 91%.(2)The main factors affecting the removal efficiency of microplastics was the dosage of PAC and pH.(3)The removal of microplastics was related to their density.ABS with a high density had the highest removal rate,while PE with the lowest density had the lowest removal rate.(4)The removal rate of microplastics varied greatly with their particle size,and the removal efficiency was highest in the range of 0.1-0.25 mm with small particle size.The study shows that by controlling the dosage of polyaluminium chloride and polyacrylamide,pH and stirring speed,the microplastics in wastewater can be effectively removed by flocculation and precipitation,so as to purify the wastewater containing microplastics.