Preparation Of PP-g-(AA-AM) Chelating Fiber And Its Adsorption Behavior For Lead Ion In Water And Regeneration

Melt-blown polypropylene(PP)fibers,which own large specific surface areas,high mechanical strength,and good corrosion resistance,have great application potential in the field of adsorption and separation.However,the nonpolarity of PP molecular chains,which leads to poor hydrophilicity and nonselectivity adsorption ability,makes the PP fibers unable to meet the application requirements for metal ions adsorption and separation in water.The graft of polarized and reactive functional groups on PP fibers can effectively improve their molecular polarity and hydrophilicity,and give PP fibers other new functions as well.In this paper,the PP were prepared by melt-blown method,then the resultant fibers were grafted with acrylic acid(AA)and acrylic amide(AM)via suspension-grafting method,and the effects of different factors on the grafting rate were examined.The modified PP fibers were applied in the adsorption of lead ions in water,and the influence of adsorption time,pH and initial concentration of lead ions on adsorption amount of chelating fiber materials in water were studied.Langmuir equation was used to describe the isothermal adsorption behavior.The adsorption of lead ions with chelating fibers was carried out in circulating cooling water system,and the efects of different flow rates,time and pH on the adsorption and regeneration of materials were analyzed.The main content of this paper is as follows:Firstly,PP was modified by suspension-grafting method with AA and AM.The main effects of the grafting rate were investigated.The effect of grafting rate on melt flow rate of the polymer was studied and the morphology and hydrophilicity of the modified fibers,which denoted as PP-g-(AA-AM),were analyzed.Secondly,the chelating adsorption capability of fibers was investigated.The effects of the initial concentration of lead ions,time,and pH on the adsorption of lead ions were studied in detail.The adsorption behavior of lead ion by PP-g-(AA-AM)was linear fitted using the isotherm equation and the mechanism of adsorption was discussed.Meanwhile,the chelating fiber’s selective adsorption ability of target Pb2+in solution that contain Na+,Mg2+,Al3+ and Ca2+as competing ions was studied.Finally,the adsorption of lead ions with PP-g-(AA-AM)was carried out in circulating water system.The effects of flow rate,time,and pH on the adsorption of lead ion were examined,and adsorption process was linear fitted by kinetic equation.At last,the effects of different desorption agents on the regeneration of the chelating fibers and the adsorption ability of the fibers after regeneration were studied.