Studies On The Preparation And Properties Of Sodium Alginate-based Composite Modified By Phosphonic Acid

Sodium alginate,which is one of the most abundant biosynthesized natural materials and rich in carboxylic acid anions and hydroxyl groups,have a wide range of uses with excellent performence of biocompatibility,biodegradability,non-toxicity,low-cost and strong chelating ability.In this paper,we used sodium alginate SA as the matrix to synthesize two different composite materials.On the one hand,the F/A balls with a particle size of about 1.5mm could be get via the method of cross-link and solidity to composite the iron ion;on the other hand,the P/A particles were prepared by the method of low temperature esterification to composite the modified para-aramid.At last,these two different forms of composite materials,EDTMPA-F/A and EDTMPA-P/A were obtained by high temperature esterification with EDTMPA.In particular,EDTMPA-F/A was synthesized by using phosphonic acid to modify SA-based composite material,which had a bifunctional group and dual-performance in controlling water pollution and catalytic synthesis of biodiesel and other applications of practical significance.These two materials were characterized by FTIR,thermogravimetric and scanning electron microscopy,and the catalytic performance and adsorption of Pb(?)were investigated.1.Firstly,the experimental results of F/A and EDTMPA-F/A showed that EDTMPA-F/A was more excellent in catalytic performance.Then a study on the single factor condition for catalytic experiments of EDTMPA-F/A was followed,and got three conclusions.The best MR value was 8:1,and the amount of EDTMPA-F/A was9wt% and the temperature is 90 oC.With the three conclusions as the catalytic conditions,the optimal MR value was 6.634:1,and the amount of EDTMPA-F/A was10.76552wt% and the temperature was 81.2713 oC,which was optimized by RSM experiment.According to the conditions of repeating tests three times,the experimental value was about 89%.And after EDTMPA-F/A used three times,the efficiency remained at 44% or more.The catalytic process of EDTMPA-F/A conformed to the reversible homogeneous secondary reaction.And the kinetic equation was r=2.17 × 10-2exp(-10.25/RT)[CA][CB]-2.71 × 10-3exp(-4.15/RT)[CC][CD].Secondly the results of the static adsorption experiments between F/A and EDTMPA-F/A showed that these two materials have adsorption effect on a variety ofcommon metal ions,and the adsorption effect of EDTMPA-F/A on Pb(?)was especially significant.Then a study on the condition of the adsorption of EDTMPA-F/A was followed,and we got a conclusion showing that the adsorption efficiency of EDTMPA-F/A on Pb(?)was the highest when the optimum pH was 3.5and the dosage of EDTMPA-F/A was 0.0150 g.By fitting with the classical adsorption model,the adsorption process of EDTMPA-F/A was influenced by the diffusion rate of the boundary layer and the diffusion process.The whole process was endothermic and the confusion on the interface was increasing.2.The studies on the adsorption process of EDTMPA-P/A began with the static adsorption experiments between P/A and EDTMPA-P/A,and the result presented that these two materials had significant adsorption properties to Pb(?)and EDTMPA-P/A is superior to P/A.Then a study on the condition of the adsorption of EDTMPA-P/A was followed,and we got a conclusion showing that the adsorption efficiency of EDTMPA-P/A on Pb(?)was the highest when the optimum pH was 4 and the dosage of EDTMPA-P/A was 0.0150 g.The adsorption kinetic curve of EDTMPA-P/A reached equilibrium in 2h,which was influenced by chelating coordination in chemical adsorption and the diffusion of liquid film.The whole process was endothermic and the confusion on the interface was increasing.At the same time,the adsorption of EDTMPA-P/A on Pb(?)was significant in binary ion system.The elution rate of EDTMPA-P/A by using HNO3 solution with pH=1 was higher,and the elution rate was still above 70% after recycling two times.The optimum conditions were that the pH value was 3.21 and the dosage of EDTMPA-P/A was 20.1876 mg and the initial Pb(?)concentration was 1.642mmol/L.These were obtained by optimizing the experimental factors which came from a new ternary quadratic regression model constructed by response surface analysis.According to the conditions of repeating tests three times,the experimental value was about 191.63mg/g and had good stability.