Study On Preparation And Properties Of Tangential Flow Chromatography Stationary Phase To Remove Heavy Metals

In this paper,nylon 66?Nylon 66?was used as matrix,?-chloropropyltrichlorosilane?CPTCS?and N,N-carbonyldiimidazole?CDI?were used as coupling agents.Diethylenetriamine?DETA?was bonded to the surface of PA66.Stationary phases PA66-CPTCS-DETA and PA66-CDI-DETA were prepared.In the experiment,the preparation process of PA66-CPTCS-DETA and PA66-CDI-DETA was optimized,and the effects of adsorption time,initial concentration,temperature,pH,and regeneration times on the adsorption performance of the stationary phases were investigated.On the basis of the above,a tangential flow chromatography device was designed and developed for the removal of heavy metals,and the adsorption performance of the tangential flow chromatography device was initially explored.The results of the study are as follows:?1?The process of adsorbing Cu²⁺and Pb²⁺withPA66-CPTCS-DETA reached the equilibrium at 150 min and 200 min,respectively,and the adsorption of Cu²⁺and Pb²⁺reached the highest amount at that time.The process of adsorbing Cu²⁺and Pb²⁺with PA66-CDI-DETA reached the equilibrium at 100min and reached the highest adsorption amount at the same time.?2?At a temperature of 25?,pH=4.0,the initial concentration of 5.0 mmol/L,PA66-CPTCS-DETA fixed relatively higher amount of Cu²⁺than any other ions.At a temperature of35?,pH=2.0,the initial concentration of 4.0 mmol/L,PA66-CPTCS-DETA fixed more Pb²⁺,and at a temperature of 25?,pH=3.0,the initial concentration of 3.0 mmol/L,PA66-CDI-DETA adsorbed more Pb²⁺.Experimental results show that,under the condition of weakly acid,the adsorption process of Cu²⁺using solid phase PA66-CDI-DETA was slightly effected by initial concentration of solvents and temperature,whereas the condition with higher pH facilitated the adsorption of Cu²⁺.?3?The process of PA66-CPTCS-DETA adsorbing Cu²⁺and Pb²⁺conformed to the Langmuir isolation adsorption model,and the adsorption kinetics conformed to the Lagergren quaqsi-first and quasi-second order kinetics models.The process of PA66-CDI-DETA adsorbing Cu²⁺and Pb²⁺conformed to the Langmuir isolation adsorption model,and the adsorption kinetics conformed to the Lagergren quaqsi-first and quasi-second order kinetics models.It suggested that the rates of PA66-CPTCS-DETA and PA66-CDI-DETA adsorbing Cu²⁺and Pb²⁺were influenced by both physical and chemical adsorption mechanisms.?4?By examining the effect of adsorption times on the adsorption of Pb²⁺using PA66-CPTCS-DETA stationary phase,it can be seen that the stationary phase had poor reproducibility,and the amount of adsorption decreased with the number of adsorption times.By examining the effect of adsorption times on the adsorption of Pb²⁺using PA66-CDI-DETA stationary phase,it can be seen that the regeneration performance of the stationary phase was better than the former,and on the premise of ensuring a certain adsorption effect,the number of regeneration is preferably three times.?5?A tangential flow chromatography device was designed and fabricated.Through the preliminary investigation of its adsorption performance,it can be seen that the concentration of Cu²⁺fixed on the stationary phase gradually decreased with the increase of the number of cycles,but the decreasing ranges of Cu²⁺was slightly smaller,and the adsorption amount was slightly lower.This result may be caused by the structure of the apparatus.