Performance comparison of two biochar filters in removing microplastics from artificial stormwater – impact of plastic type and size
Year: 2024
Type: dissertation
Abstract: This thesis studied the effectiveness of biochar as a filtration material for removing microplastics from artificial stormwater as a solution to address the global environmental threat caused by microplastic pollution.More specifically, the study focused on comparing the filtering performance of two different biochar materials, a higher temperature processed spruce biochar and a lower temperature processed birch biochar.Additionally, the effect of particle size and polymer type was studied by comparing the retention efficiencies of two different microplastic size fractions (500 μm-300 μm and 212 μm-106 μm) and three different polymer types, linear lowdensity polyethylene (LLDPE), polypropylene (PP) and tyre wear particles (TWP).The surface morphology of the biochar was examined with a scanning electron microscope (SEM) and counting the microplastic particles in the post-filtration suspension was done using an optical stereo microscope.Visual identification of the samples was made possible by selecting suitable size fractions and distinctively coloured plastic materials.The controlled laboratory filtrations performed in the study provided a controlled environment to minimise the influence of external factors and contamination and enabled the specific comparison of individual factors.Comparison of the measured microplastic particle amounts and a combination of statistical tests was used in the research to establish that biochar is significantly effective at reducing microplastic concentrations, larger microplastic particles were consistently filtered more effectively than smaller ones, and that significant differences were observed in the filtration efficiency among different types of microplastics.While the comparison of the two biochar types showed no statistically significant difference in their filtering performance, sorption capacity calculations estimated that the high temperature spruce filter was 10% more effective than the low temperature birch filter.The results of this study show the potential of biochar as a sustainable and effective solution for microplastic removal from stormwater-like medium, while underscoring the need to further study the properties of biochar and microplastic that impacts the filtration efficiency to optimise biochar's application in real-world scenarios. POLYPROPYLENE (PP)Bottle caps, potato chip bags, microwave dish trays, yogurt containers, single-use face masks, pill containers, tote bags, sports clothes POLYVINYL CHLORIDE (PVC) Drainage pipes, window frames, cable insulation, roofing and flooring materials, raincoats, rubber boots.
Author: Leinonen, Matti
Institution: University of Eastern Finland
Language: English
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7215339632