Co-doped zeolitic imidazolate framework-L for more rapid phosphate removal
In order to reduce the harm of water eutrophication and improve the efficiency of phosphorus removal by adsorption method,this paper studied the effect of cobalt doping on the phosphate adsorption capacity of Zinc-based leaf zeolitic imidazolate framework-L(Zn-ZIF-L).In this paper,intermittent adsorption tests were used to study the influence of various influencing factors on the adsorption.XRD,XPS,FT-IR and other methods were used to study the surface microstructure of the materials to speculate the possible adsorption mechanism.It was found that the adsorption performance of Zn was the best when the initial molar ratio of Zn to Co was 9.5:0.5.After doping,the adsorption capacity increased by 55%within 10min,the maximum adsorption capacity could reach 85.68mg/g,and the adsorption performance was maintained under different temperature,concentration,pH value of 4~8,different anions and humic acid environments.When the initial concentration was 10mg/L,more than 97%of phosphorus could be adsorbed.More than 93%of phosphorus could be retained in 0.1mol/L Cl-or NO3-.Additionally,the chemical bonding between P-OH and Zn-OH/Co-OH,electrostatic interaction,and hydrogen bond interaction played a leading role in phosphate adsorption.Moreover,Co(0.5)-Zn-ZIF-L could keep a high adsorption capacity after four cycles.These findings suggest that Co(0.5)-Zn-ZIF-L can effectively remove phosphate from water.