Study On Removal Of Dyes And Antibiotics Molecules From Water Pollution By Charged Boron Nitride Membranes

The problem of water pollution is getting worse.All kinds of organic pollutants,such as printing and dyeing wastewater and antibiotic sewage,continue to harm the natural environment and public health.In the face of various contaminants in the water environment,seeking efficient environmental protection and targeted means is necessary.Membrane separation technology is an effective means of high efficiency and energy saving and is widely used in actual water treatment.The membrane material is the core technology of membrane treatment technology.As a new kind of membrane materials,two-dimensional material exhibit high solute repulsion and solvent transport properties in membrane structure,which make membrane separation technology show broad prospects.As a promising two-dimensional material,boron nitride nanosheets show great potential in gas separation,proton exchange,electrodialysis,water filtration,etc.The ammonia-functionalized BN-based membranes exhibit ultrafast molecular transport in molecular separation,nanochannels limit effective molecular sieve separation in aqueous solution and organic solvent.Therefore,it is necessary to construct nanofiltration membranes with stable screening performance in various solvents.In this study,by controlling the surface charge of the BN membrane,the transport of molecules through the BN membrane is controlled.The electrostatic interaction between the surface of the highly charged BN membrane and charged pollutant molecules makes the membrane have excellent mass transport and solvent penetration.This simple and scalable surface charge control method provides a new idea for water purification.The main experimental results obtained in the experiment are as follows.（1）The bulk phase boron nitride was stripped into hydroxy-functional boron nitride nanosheets by ball milling with glucose as the ball milling agent.A stable and dispersive BN solution was prepared by dialysis and centrifugation.Positively charged PBN membranes and negatively charged SBN membranes were prepared by mixing polyelectrolyte and dispersion solutions in different proportions.（2）The prepared PBN and SBN membranes are used for separation test and stability test of dye molecules and antibiotic molecules in aqueous and organic systems.Based on size screening and electrostatic action,separation tests were carried out on the charged BN membrane.Positive and negative charged dyes and antibiotics were selected for the separation test.The results showed that the removal rate of positive charged dyes and doxycycline,an acidic antibiotic,reached 100%in the water system with PBN₁ membrane.The removal rate of SBN₁ membrane to negative charge dye reached 100%,and the removal rate of alkaline antibiotic nystatin reached 96%.In the nanofiltration of organic solvents（methanol,ethanol,isopropyl alcohol,acetonitrile,dimethyl sulfoxide）,PBN₂ and SBN₂membranes also showed excellent performance,and the permeability of acid fuchsin in acetonitrile was 809 L/m² h bar and 97.71%.The permeability of DMSO to AB was 290L/m² h bar and 94.94%.The data show that the charged BN membrane has high separation performance and stability in water and organic solvents,and has certain application potential in the removal of pollutants in the membrane,and also provides a new idea for the preparation of the charged membrane and water treatment.