Functionalization And Performance Of Nonwoven Fabrics Based On Mussel Biomimetic Coupling Of Thiol-en

Environmental pollution has always been an issue of public concern,especially water pollution.Heavy metals in polluted water are often absorbed by plants and enter the food chain,resulting in adverse consequences for human beings and animals.How to solve the heavy metal pollution is still an important problem to be solved in our country at the present stage.In this paper,in view of the problems existing in the adsorption and separation of heavy metal ions by functionalized polypropylene non-woven fabric,the rapid bionic modification technology of mussel was deepened,and the molecular brush functionalization method of polypropylene surface with bionic coupling mercaptan-alkene click reaction was developed to increase the density of functional groups on the surface of materials,so as to provide new materials and methods for the adsorption and removal of heavy metals.Catechol modified non-woven fabric PP/CAT was prepared by rapid mussel biomimetic method,and sulfhydryl group was introduced into the functional layer to obtain PP-SH.Two kinds of polyacrylic acid molecular brush functionalized polypropylene nonwovens PP-g-AA and PP/CAT/AA were prepared by the combination of fast mussel bionics and mercaptan-alkene free radical click reaction by"graft from"and"graft to"methods,respectively.The adsorption materials of the prepared non-woven fabrics were characterized by SEM,FTIR and XPS.The adsorption properties under different experimental conditions are discussed,and the results are as follows:（1）the biomimetic coating of mussel was rapidly prepared by using catechol as biomimetic precursor of catechol combined with ammonium persulfate and ethylenediamine.By adjusting the ratio of ethylenediamine to ethylene dithiol,sulfhydryl group（PP-SH）was introduced into the surface of polypropylene non-woven fabric,and then polyacrylic acid molecular brush（PP-g-AA）was prepared by mercaptan-alkene click reaction.The results show that sulfhydryl can be introduced by reduction,and the highest sulfhydryl content can reach 7.32mmol/g when the ratio of ethylenediamine to ethylene dithiol is 1:1.Adsorption experiments show that PP-SH and PP-g-AA have strong adsorption capacity for Pb²⁺,Cu²⁺and Cd²⁺.The theoretical maximum adsorption capacity of PP-SH for Pb²⁺,Cu²⁺and Cd²⁺is 90.224,80.88 and 87.775 mg/g respectively,while the theoretical maximum adsorption capacity of PP-g-AA for Pb²⁺,Cu²⁺and Cd²⁺is 99.201,95.884 and 100.153mg/g,respectively.The two kinds of non-woven fabrics showed excellent regeneration properties.（2）In order to solve the problem of poor alkali resistance of mussel biomimetic modified nonwovens,PP/CAT was obtained by glutaraldehyde cross-linking on the basis of rapid bionic mussel.However,the surface group of PP/CAT is single and the number is small,so it is proposed to use the free radical click of mercaptan alkene to introduce the molecular chain into the surface of PP/CAT by macromolecular grafting（graft to）method to obtain PP/CAT/AA non-woven fabric.Through the stability test,it is proved that the PP/PCA non-woven fabric crosslinked by glutaraldehyde has good resistance to alcohol solution,strong alkaline solution and various organic solvents.When the ratio of ethylene dimercaptan to acrylic acid is 1:5,the highest grafting rate can reach 38.98%.The adsorption experiments show that the adsorption performance of PP/CAT/AA for heavy metals is more than 2 times higher than that of PP/CAT.According to the Langmuir model,the maximum theoretical adsorption capacities of PP/CAT to Pb²⁺,Cu²⁺and Cd²⁺were 58.414,58.703 and 48.848 mg/g,respectively,while those of PP/CAT/AA were 125.383,124.45 and 120.18 mg/g,respectively.