Experimental Study On Preparation And Heavy Mental Adsorption Capability Of Modified Membrane

The adsorption of Cu²⁺?Cd²⁺and Pb²⁺ from aqueous solution was studied by modified Nylon66 membrane which was modified with Diethylenetriamine?DETA?by using two kinds of activators N,N'-carbonyldiimidazole?CDI?and using instrumental characterization analysis its structure.In the static adsorption performance test,the effects of pH,adsorption time,initial solution ion concentration and temperature on the adsorption capacity of two modified nylon film materials were investigated.The adsorption kinetics,isothermal adsorption experiment,adsorption selection Sex test and reproducibility of repeatability,etc.,in order to modify the nylon membrane material in the treatment of heavy metal wastewater to provide technical support,the main results are as follows:?1?Through the study of the factors influencing the adsorption capacity of modified nylon membrane,the optimal pH value of adsorption of Cu²⁺ and Cd²⁺ solution was 4.6,the adsorption time was 120 min and 90 min,the conditions of adsorbing Pb²⁺ is under the value of pH 4.6,the conditions of adsorbing Cu²⁺,Cd²⁺and Pb²⁺ from aqueous solution are that under the temperature 45 ?,adsorption time is 90 min,the modified membrane quantity is 120 mg,the initial concentration of water sample is 2.5 mmol /L.Under this situation,the adsorption of CDI-DETA-PA66 was 51.9553 mg/g,12.9253 mg/g,49.9011 mg/g for Cu²⁺,Cd²⁺and Pb²⁺,respectively,but the conditions of adsorbing Cd²⁺ of GA-DETA-PA66 is under the value of pH 5.8,adsorption time is120 min.Under the same situation,the adsorption of GA-DETA-PA66 was 35.7830 mg/g,13.2155 mg/g,16.2862 mg/g,they are higher than the adsorption capacity of the unactivated nylon membrane,while common one was 2.0274 mg/g?1.6450 mg/g and 2.7935 mg/g.?2?The kinetics curves of Cu²⁺,Cd²⁺ and Pb²⁺ adsorbed on the modified nylon membrane were fitted by Lagrone quasi-first order kinetic model and quasi-second order kinetic model.The results showed that the process of adsorption of Cu²⁺,Cd²⁺ and Pb²⁺ can be better described by quasi-second order kinetic model,indicating that the reaction is chemically adsorbed.?3?The adsorption isotherms of Cu²⁺,Cd²⁺ and Pb²⁺ were fitted by Langmuir adsorption isotherm equation and Freundlich adsorption isotherm equation.The results showed that the adsorption effect of modified nylon membrane on Cu²⁺,Cd²⁺ and Pb²⁺ was more affected by Freundlich adsorption isotherm equation and it is suitable for 1 <n <10,indicating that the modified nylon membrane is easy to adsorb heavy metal ions,and the adsorption sites of the modified nylon membrane may be unevenly distributed.?4?The modified nylon membrane has the selective adsorption capacity for Cu²⁺,Cd²⁺ and Pb²⁺ solutions,they can be used to selectively separate Cu2 + and Cd²⁺ binary mixed solution and Pb²⁺ and Cd²⁺ binary mixed solution,and the adsorption capacity of Cu²⁺ and Pb²⁺ is larger than that of Cd²⁺.The modified nylon membrane modified nylon membrane can be used to selectively separate Cu²⁺ and Cd²⁺ binary solution and Pb²⁺ and Cd²⁺ binary mixed solution,which has certain reference value for the removal of heavy metals.?5?After modification,the pore size,flexibility and mechanical strength of nylon membrane did not change greatly.With the addition of 1 mol/L ethylenediaminetetraacetic acid disodium solution as the eluent,the adsorption capacity of Cu²⁺ modified by nylon membrane after repeated regeneration is almost unchanged,so it has good reusability and reproducibility,especially The modified nylon membrane adsorbed Cu²⁺ film showed light blue and its hydrated ion color consistent,so the film also has the ability to quickly detect heavy metal Cu²⁺.