Study On Preparation Of Copper Ion Loaded Polyacrylonitrile Fiber And Its Removal Of Phosphate From Water

Eutrophication of water bodies is a topic of global concern,with the limiting factor being total phosphorus.The high levels of phosphorus in water bodies in recent years are mainly derived from anthropogenic factors such as industrial production,agricultural fertilization,livestock farming and residential life.In addition,phosphorus is a non-renewable resource and an essential element for the survival of plants and animals on earth.Therefore,the recycling of excess phosphorus in water bodies can not only alleviate eutrophication in water bodies,but also has important research value in achieving a high degree of resourceful use of phosphorus.Currently,the main methods of phosphorus removal are chemical precipitation,biological methods,membrane separation and adsorption methods.Among them,adsorption has received a lot of attention due to the advantages of simple operating conditions,abundant material sources and low risk of secondary pollution.However,traditional adsorbents are mostly in powder form and it is difficult to recycle,which limits their application development.Therefore,it is of great research significance and practical application if polymer,fiber and other matrix materials are used as adsorbent carriers to prepare solid-loaded adsorbents for the efficient removal of phosphate and recycling of adsorbents.In this study,a new phosphate adsorbent（PAN_AF-Cu）was successfully prepared by amination and coordination reactions using polyacrylonitrile fiber as raw material.The physical and chemical characterization of PAN_AF-Cu was carried out by Scanning Electron Microscopy（SEM）,Elemental Analysis（EA）,X-ray Diffraction（XRD）and Fourier Transform Infrared Spectroscopy（FTIR）,and the experiments on the adsorption performance of PAN_AF-Cu on phosphate in water bodies were carried out.The results showed that the adsorption efficiency of PAN_AF-Cu was good at p H 5-9,and the maximum adsorption capacity of 26.98 mg P g^-1 was reached at neutral.The adsorption process of PAN_AF-Cu on phosphate was closer to chemisorption,and the adsorption equilibrium was basically reached within 30 min.The adsorption of phosphate by PAN_AF-Cu was found to be more in line with the pseudo-secondary kinetic adsorption model,and the maximum theoretical adsorption capacity of phosphorus was 49.02 mg P g^-1.It was also found that under the interference of coexisting anions,the effect on the adsorbent was SO4^2-﹥CO3^2-﹥Cl^-﹥NO3^-.The results of adsorption-desorption cycle experiments showed that the removal rate could still reach more than 90%after 8 adsorption-desorption cycles.In the continuous flow experiment,it was found that the phosphate removal rate of PAN_AF-Cu could be maintained above 99%when the discharge volume was less than 2700 m L.Therefore,PAN_AF-Cu was selected as an adsorbent for the effective removal of phosphorus from water bodies with excellent recyclability and potential use,taking into account the synthesis conditions of the material,adsorption capacity,and economic factors.The adsorbent possesses the characteristics of fast adsorption-desorption rate and stable performance,which are sufficient to show that PAN_AF-Cu has good application prospects in the field of phosphate removal and recovery from water bodies.