Preparation Of Tourmaline-based Composites And Their Applications In Dyes And Ammonia Nitrogen Wastewater

The rapidly growing world population and social economy have created a huge demand for resource supplies,especially fresh water resources.However,there are still a large number of untreated dye industrial wastewater,domestic sewage and agricultural wastewater will be directly discharged into river,causing water pollution.Tourmaline is a kind of environmentally friendly inorganic mineral particle with a large number of hydroxyl groups on the surface.It has permanent spontaneous polarization effect,piezoelectric effect and thermoelectric effect,which can reduce water molecular clusters,regulate the p H value and conductivity of water.Tourmaline has good removal efficiency for dye and ammonia nitrogen wastewater.In this study,based on the excellent properties of tourmaline,it was blended into PVA/PAM hydrogel and PVDF separation membrane respectively.Not only the influence of tourmaline on the structure of hydrogel and separation membrane was studied,but also the adsorption performance of hydrogel and separation membrane on acid fuchsin dye and ammonia nitrogen wastewater was studied.Firstly,tourmaline particles were blended into PVA/PAM hydrogel,and a series of PVA/PAM/TM hydrogels were prepared.The results showed that all the hydrogels had good thermal stability,and the addition of tourmaline particles could significantly improve the hydrophilicity and tensile strength of the hydrogels.At the same time,PVA/PAM/TM hydrogel could regulate p H and conductivity of waterbody.Adsorption experiments showed that the removal efficiency of P-TM_2.0%hydrogel for acid fuchsin dye and ammonia nitrogen wastewater reached 66.90%and 72.91%respectively,indicating that tourmaline was a functional green water purification material.In order to reduce the agglomeration of tourmaline,silane coupling agent KH-550was used to modify tourmaline.Then the modified tourmaline particles were added to the PVDF casting solution by blending,and a series of PVDF/TM_KH-550 composite membranes were prepared by NIPS.The results showed that the agglomeration of tourmaline could be reduced by modification.With the increase of TM_KH-550nanoparticles content,the removal efficiency of acid fuchsin dye and ammonia nitrogen wastewater increased gradually.For PVDF/TM_KH-550 composite membranes,the results showed that the addition of TM_KH-550 nanoparticles improved the hydrophilicity,porosity and pore size of the membrane,increased the permeation flux.At the same time,the addition of TM_KH-550 nanoparticles making the surface of the membrane more electronegative,which was conducive to the removal of anionic dye wastewater.The removal efficiency of the composite membrane on acid fuchsin dye and ammonia nitrogen solutions could reach 85.11%and 75.40%,respectively.The p H and conductivity of deionized water after membrane filtration were tested.At 0.2 MPa,it was found that both p H and conductivity increased.The above results showed that tourmaline can not only activate water bodies but also remove pollutants in water.