Preparation Of Magnetic Bioflocculants And Its Adsorption Efficiency For Microplastics

At present,marine water pollution is becoming more and more serious with the development and utilization of marine resources by humans.Among them,microplastics have become a global pollution that seriously affects human health and the ecological environment.Therefore,the removal of microplastics has become a current hot issue.In this study,a high-efficiency and easy-to-separate magnetic bioflocculants was used to adsorb and remove the microplastics in the water.Two different types of microbial flocculants were cross-linked with magnetic Fe3O4 particles,and the materials produced under different proportions were analyzed by morphological characteristics observation,scanning electron microscopy,EDS,FTIR and other characterization methods,and the optimal microbial flocculant and The ratio of magnetic Fe3O4 particles shows that when the ratio of magnetic Fe3O4 particles and J1 bioflocculants is 1:1,and the ratio of magnetic Fe3O4 particles and F2 bioflocculants is 2:1,the bioflocculants successfully cross-linked,The corresponding magnetic bioflocculants was obtained for use in subsequent experiments.Analyze the influence of various factors on the removal efficiency of microplastics.For J1 magnetic bioflocculants,when the dosage of magnetic bioflocculants is 1.0 g / L,the p H is 7.0 and the concentration of microplastic particles concentration is 1.5 particles / ml.The overall adsorption effect is the best,and its removal rate can reach 90%.At the same time,the size of the microplastic particle size and its adsorption capacity have little effect.For the F2 magnetic bioflocculants,when the dosage of the magnetic bioflocculants is 1.5 g / L,the p H is 7.0,the microplastic particle concentration is 1 particles / ml,and the microplastic particle size is 40 mesh.Its overall adsorption effect is the best,and its removal rate can reach 100%.For two different magnetic bioflocculants,J1 magnetic bioflocculants Langmuir model R2=0.8957,Freundlich model R2=0.915,F2 magnetic bioflocculants Langmuir model R2=0.995,Freundlich model R2=0.9949,two The fitting of the three models is relatively good,indicating that the whole adsorption process is more complicated and involves multiple steps of reaction.Kinetic analysis found that for J1 magnetic bioflocculants,the overall trend is consistent with pseudo-first-order reaction kinetics,but not quasi-second-order reaction kinetics,which also illustrates the adsorption of microplastics on J1 magnetic bioflocculants.The main speed limit step is physical adsorption(electrostatic adsorption).For the F2 magnetic bioflocculants,the adsorption process conforms to the pseudo-second-order reaction kinetics but not the pseudo-first-order reaction kinetics,indicating that the speed-limiting step of the F2 magnetic bioflocculants in the process of adsorbing microplastics is mainly by chemical adsorption To control completion.