Study On The Preparation And Humic Acid Adsorption Behavior Of PEI Modified Graphite/Bamboo Powder Based Magnetic Materials

Water pollution of the world is a major problem in the field of water resources protection.It will not only aggravate the shortage of water resources,but also cause devastating damage to the ecological environment.Humic acid（HA）as one of the main organic pollutants,which is widely existed in natural lakes and livers.And it has seriously affected the safety of drinking water.If these pollutants are not treated in a timely and effective manner,they will directly threaten human survival.How to better treat sewage is a problem that needs to be solved urgently.The topic of this thesis is to study the preparation of new modified magnetic nanocomposites and explore its adsorption and removal of natural organic pollutants HA in water.The specific results are as follows:1.Fe₃O₄ and graphite/bamboo powder were combined by hydrothermal method,and then the obtained materials were chemically modified with polyethyleneimine（PEI）.The results show that Fe₃O₄ can be well combined with two different substrates.At the same time,by adjusting the concentration of PEI in the impregnation solution,it was found that when the concentration of PEI was 5.0wt%,the impregnation reached saturation,and the adsorption capacity did not change much with increasing the concentration.2.The results show that Fe₃O₄ has a good dispersion on the surface of the substrate,and its agglomeration rate is greatly reduced.The content of N on the surface of PEI was improved before and after modification.The VSM results show that the two materials have good saturation magnetization,which is conducive to the separation and recovery of adsorbents.3.The adsorbents were tested in different initial concentrations,different contact time,various pH environments and cationic concentrations.The results showed that:the graphite modified material followed Freundlich adsorption isotherm model,while the bamboo powder modified material followed Langmuir adsorption isotherm model.Both of the materials conformed to the pseudo-second-order adsorption kinetic model.The adsorption capacity of the two adsorbents decreased with the increase of pH.At the same time,the increase of cationic concentration in the solution can promote the adsorption.4.After five cycles of regeneration,the adsorption capacity of the material is still more than 80%of its initial adsorption capacity.The adsorption mechanisms have been deeply explored and the results show that electrostatic interactions play an important role in the whole adsorption process.