Description:
Biochar is used for the removal of antibiotics from sewage, where microplastics are arising contaminants. However, whether adsorption capacity of microplastics for antibiotics and how different particle sizes and types of microplastics affect the adsorption of antibiotics by biochar have not been studied. The adsorption of PVC (10, 100, 500, 2000 μm), PLA (30, 100, 500, 2000 μm) with wheat straw biochar and their combinations on tetracycline and aureomycin were investigated by adsorption isotherm and kinetics experiments. The results illustrated that PLA30+BC had the highest adsorption capacity for tetracycline (25.00mg·g-1), which was greater than that of other particle size microplastics for tetracycline (20.44-24.57 mg·g-1). Furthermore, when PLA and biochar were coexisted, tetracycline adsorption increased by 13.69%, 6.28%, 5.49% and 4.54% for PLA30+BC, PLA100+BC, PLA500+BC, and PLA2000+BC, respectively. This may be due to the adsorption of antibiotics by the pore structure of the small particle size microplastics themselves and the reduction of small molecules of dissolved organic carbon. The results demonstrated that microplastics can adsorb antibiotics; in addition, they improve the adsorbability of biochar for antibiotics. Therefore, when biochar is used to remove antibiotics from effluent, in order to effectively remove antibiotics from effluent using biochar, it is essential to consider the potential interaction between biochar and microplastics