Preparation Of Sodium Alginate Based Composite Gel Materials And Their Antibacterial And Heavy Metal Ion Adsorption Properties

Sodium alginate is often used as a medical dressing and adsorbent material because of its massive carboxyl group and its ability to form hydrogels through calcium crosslinking.However,the poor physical properties of sodium alginate hydrogel restrict its application.In this paper,an antibacterial hydrogel membrane and heavy metal ion adsorption gel microspheres are constructed using sodium alginate as a matrix.The combination with other materials not only improves its physical properties,but also has a good performance in the field of medical dressings and heavy metal adsorption.In the second chapter,a near infrared response hydrogel membrane(STF hydrogel membrane)with photothermal sterilization was prepared by tannic acid iron and sodium alginate,and the optimum concentration of tannic acid was 40%.Through the characterization of FTIR,SEM and mechanical properties test,it is found that the STF hydrogel film has excellent mechanical properties,and the mechanical properties of SA hydrogel membrane are improved,and it is very easy to process.More importantly,the STF hydrogel film prepared has good photothermal effect,and the temperature rises sharply to 54 degrees after low intensity near infrared(0.3 W/cm~2)light irradiating 5 min.In vitro antibacterial experiments showed that the STF hydrogel membrane could effectively kill nearly 90%of the bacteria after 5 min near infrared irradiation.In vivo antibacterial experiments,STF hydrogel membrane can effectively treat wound infection and promote wound healing.In addition,the STF hydrogel membrane prepared has high biocompatibility.In the third chapter,a gel ball(ST gel ball)with good adsorption properties for chromium ions was constructed by tannic acid and sodium alginate.The optimum mass ratio of SA and TA was 1:1.The characterization of FTIR and SEM showed that the surface groups of ST gel balls adsorbed chromium ions.Single factor static adsorption experiments were carried out to study the adsorption of chromium on ST gel balls at p H 3.Fitting the experimental results with the kinetic equation,it is found that the adsorption reaction of ST gel balls to chromium ions is more consistent with the quasi two stage kinetic equation,indicating that the adsorption of chromium ions by ST gel balls is chemisorption.Fitting the experimental results with the adsorption isotherm model,it is found that the adsorption reaction of ST gel balls to chromium ions is more consistent with the Langmuir isotherm model,indicating that the adsorption of chromium ions on ST gel balls is monolayer,and the maximum adsorption capacity is 135.3 mg/g by fitting results.Besides,after the 5 adsorption desorption cycle experiments,the removal rate of chromium ions by ST gel balls is still over 90%.In the fourth chapter,a gel ball(STR gel ball)with good adsorption properties for iron ions was prepared by using rice bran hemicellulose,tannic acid and sodium alginate.The optimum mass ratio of SA and RBH was 5:1.The characterization of FTIR and SEM indicates that the surface groups of STR gel balls adsorb with iron ions.Single factor static adsorption experiments were carried out to study the adsorption of iron ions on STR gel balls at p H 4.Fitting the experimental results with the kinetic equation,it is found that the adsorption reaction of STR gel spheres to iron ions is more consistent with the quasi two stage kinetic equation,indicating that the adsorption of STR gel balls on iron ions is chemisorption.Fitting the experimental results with the adsorption isotherm model,it is found that the adsorption of STR gel balls on iron ions is more consistent with the Langmuir isotherm model,indicating that the adsorption of iron ions on STR gel balls is monolayer,and the maximum adsorption capacity is 119.0 mg/g by fitting results.Besides,after 5 adsorption desorption cycles,the removal rate of iron ions by STR gel ball is still over 80%.