Collagen Peptide-based Nanomaterial For Uranyl Ions Separation In Complex Aqueous Matrix:Preparation And Adsorption Study

In this study,collagen polypeptide,the hydrolyzate of tannery waste,was used as material to prepare adsorbents of BSA-BT-NSs,HTO-BSA-NSs,and NCFs-HTO-BT by immobilizing bayberry tannin?BT?and hydrous titanium oxide?HTO?with the principles of protein chemistry,tanning chemistry,analytical chemistry,and chemical engineering.Furthermore,the adsorption performances of above three adsorbents were systemically investigated in wastewater and spiked seawater.Firstly,BSA-BT-NSs was prepared immobilizing BT onto the surface of bovine serum albumin nanospheres?BSA-NSs?shaped by the desolvent method.BSA-BT-NSs possessed remarkable stability under ⁶⁰Co?-ray irradiation at the total doses ranging from 10 kGy to 350kGy,and its UO₂²⁺adsorption capacity decreased by 11.588%.Adsorption results showed that the optimal pH was 5.0,the reaction reached equilibrium within 300 min,the maximum q_e was 341.696 mg g^-1,and distribution coefficient and selectivity ratio for UO₂²⁺were 2290.0mL g^-1 and 96.7%in a multi-coexisting matrix included various mineral ions,respectively.In addition,characterization analysis shown that BT bounded with with BSA by hydrophobic bond,hydrogen bond,and covalent bond,while the ortho-phenolic hydroxyl groups BT and nitrogen-containing and oxygen-containing groups of BSA were main adsorption sites.Secondly,HTO formed by hydrolyzation and polymerization of Ti⁴⁺was immobilized onto BSA-NSs with the functional groups of amino groups and guanidine groups to prepare HTO-BSA-NSs.After 14 days of cultivation in seawater containing Marinobacter sp.,the structure of the nanospheres of HTO-BSA-NSs was complete,and no cell was found in the culture.The adsorption results demonstrated that HTO-BSA-NSs are capable of uranium capture from a complex aqueous matrix with a low uranium concentration with the experimental maximum q_e of 64.535 mg g^-1,the adsorption reaction reached equilibrium within 180 min and the adsorption capacity of HTO-BSA-NSs for UO₂²⁺is up to 0.562 mg g^-1 in seawater containing 100 times its coexisting ions.The dehydrated complexation between HTOs and uranium should be the main adsorption reaction,and amino on BSA can offer lone electron pair to UO₂²⁺.Thirdly,waste collagen fibers were mechanically pulverized to obtain nano-collagen fiber NCFs,then both BT and HTO were immobilized onto it to prepar NCFs-HTO-BT.As the ratio of NCFs:HTO:BT is 10:1:2,the prepared adsorption material was dark orange and possessed a highest uranium adsorption capacity in spiked seawater.NCFs-HTO-BT can capture UO₂²⁺effectively in weakly acidic,neutral and weakly alkaline seawater,and reaction reached equilibrium within 180 min.The experimental q_m is 100.644 mg g^-1.The adsorption capacity of NCFs-HTO-BT for UO₂²⁺is up to 0.558 mg g^-1 in seawater containing 100 times its coexisting ions.In simulated nuclear industry uranium-containing wastewater,the optimal adsorption pH of NCFs-HTO-BT is 5.0;the reaction reached equilibrium within 6 h;the experimental q_m is 393.186 mg g^-1.In the multiple coexisting wastewater system,including UO₂²⁺,Ca²⁺,Mg²⁺,Mn²⁺,Co²⁺,and Sr²⁺,the adsorption performance of NCFs-HTO-BT for uranium by is pH-depanded.Characterization analysis showed that the adsorption of NCFs-HTO-BT on UO₂²⁺was mainly due to the dehydration condensation between UO₂²⁺and HTO,the complexation between the phenolic ortho phenolic hydroxyl groups of BT,and the nitrogen-oxygen function on the polypeptide chain.