Preparation And Performance Study Of Tourmaline Functional Composite Membrane

Water is the most important resource for organisms on the earth,and it is also the most important component of living entities.Although 70% of the earth is covered by water,the available fresh water resources are very limited.The increasing shortage of fresh water resources not only seriously affects human life,but also has a very negative impact on the ecological environment.Water pollution is one of the important reasons for the shortage of global water resources.Water pollution is caused by hundreds of inorganic and organic pollutants in water,some of which are highly persistent,toxic and carcinogenic.The increasingly serious water pollution not only reduces the use function of water body,further aggravates the shortage of water resource,but also seriously threatens the safety of drinking water and human health.Therefore,how to effectively purify polluted water has become an important problem to be solved urgently.In recent years,membrane separation technology has become an important method in wastewater treatment,with its advantages of low energy consumption,high separation efficiency and no secondary pollution.Aiming at the problem that the separation membrane is easily polluted during the membrane separation process.In this study,we adopted the environment-friendly inorganic mineral,tourmaline,as the modified material on account of the tourmaline with the characteristics of activating water and regulating the p H and conductivity of solutions.Through different methods,tourmaline was introduced into the membrane to explore its influence on the structure and performance of the membrane and its effect on water.Firstly,the tourmaline particles were blended into a PVC casting membrane solution,and hybrid membranes with different amounts of tourmaline were prepared by a phase inversion method.The results showed that the addition of tourmaline particles improved the hydrophilicity,porosity and pore size of the membrane,increased the permeation flux.At the same time,the roughness of the membrane surface decreased,the surface electronegativity was lower,and the anti-fouling performance of the membrane was improved.Using BSA as the pollution model,the anti-fouling performance of the membranes were tested.The hybrid membranes had higher fouling recovery rate and lower total fouling index.In addition,the p H value and conductivity of the filtered water were measured,the p H value and conductivity were increased,indicating that tourmaline had a certain effect on water.Although the blending method is simple,some tourmaline particles will be embedded.In order to make tourmaline contact with water better,different content of tourmaline particles were fixed on the surface of PVDF commercial membrane by vacuum-assisted filtration,and PVDF/PVA/Tourmaline composite membranes were prepared.The test results showed that the anti-fouling performance of the composite membranes have been greatly improved,and the effect of tourmaline on water is more obvious.When humic acid(HA)as the pollution model,the composite membrane with tourmaline content of 0.5 wt% has the highest rejection rate of HA was 91.2 %.After 90 min of HA dynamic filtration,the composite membrane flux recovery rate was 87.6 %,which was 26.2 % higher than that of pure PVDF membrane.The p H and conductivity of the filtered water were characterized.The p H increased from 5.58 to 7.20,and the electrical conductivity increased from 2.03 ?s/cm to 8.45 ?s/cm.The p H and electrical conductivity improved significantly.