Preparation And Application Of Seabuckthorn Branch Powder-based Biocomposites

Seabuckthorns widely grows between 2°-123°longitude and 27°-69°latitude.Seabuckthorn is mostly distributed in the"three north"areas,such as 19 provinces that Shanxi,Shaanxi,Gansu,Qinghai,Xinjiang,Tibet and other,and autonomous regions.China is the largest planting area and most species of Seabuckthorn in the world,accounting for 90%of the world’s Seabuckthorn resources.Compared with the commercial development technology of seabuckthorn fruits,seeds and leaves,almost all the branches of seabuckthorn with huge resources are abandoned in the field or burned as biofuels for daily life.Accordingly,the research and development of functional materials of seabuckthorn branch powder can not only solve the practical problem of utilization of biomass resources of seabuckthorn branch,but also prolong the industrial chain of biomass materials of seabuckthorn economic forest,so it has important social significance and economic value.In this paper,a dye adsorbent with low cost and environmental friendliness was prepared by grafting Seabuckthorn branch powder with dihydrazide adipate,which can effectively solve the shortcomings of poor adsorption ability and low efficiency of original Seabuckthorn branch powder（SBP）.In addition,the intermediate of controlled release material was prepared by combining SBP with titanium ion.The product can be applied to the response of fertilizers and pesticides.Release.The main results are as follows:（1）ADH@SBP material for selective adsorption of alizarin red S was synthesized by free radical grafting with abandoned seabuckthorn branches and adipic acid dihydrazide（ADH）,seabuckthorn branches powder（SBP）as the main body and ADH as modifier.The morphology and structure of modified SBP and SBP were characterized by scanning electron microscopy（SEM）and Fourier transform infrared spectroscopy（FTIR）.The effects of modifier,dosage,p H and temperature on the adsorption rate of alizarin red S by ADH@SBP were investigated by single factor experiments,and the optimal region was determined.The optimum adsorption conditions of ADH@SBP were obtained as follows:p H 2,temperature 50 ℃,concentration of ADH@SBP 2.4 g/L,adsorption time t=600 min,max Qe is 90 mg/g for alizarin red S.The adsorption kinetics and isotherm of ADH@SBP were studied.It was found that the adsorption isotherm of ADH@SBP for alizarin red S was in accordance with Langmuir adsorption isotherm equation.The adsorption kinetics of alizarin red S on SBP surface was dominated by single-layer chemical adsorption.The adsorption kinetics model was in accordance with pseudo-first-order model and intraparticle diffusion model.Chemical adsorption is the main speed control step of adsorption.Compared with the original SBP,the prepared ADH@SBP exhibited good adsorption properties for alizarin red S.（2）IBA-Ti⁴⁺≡SBP was synthesized by loading IBA on SBP surface thought the dynamic chelating bond,SBP as the main body and Ti⁴⁺used as component of the dynamic chelating bond.The formation process of Ti⁴⁺≡SBP complex was characterized by FTIR,SEM and XPS.IBA-Ti⁴⁺≡SBP have comprehensive responses of p H,temperature and ion.The p H response,temperature response and ion response of IBA-Ti⁴⁺≡SBP were systematically analyzed and studied.The results showed that the controlled release with IBA-Ti⁴⁺≡SBP（98.91%and 99.02%）in solution was enhanced under the conditions of p H=10.5 and 50.0 ℃.Compared with Na⁺,the release of IBA-Ti⁴⁺≡SBP in Ca²⁺solution was significantly increased.IBA-Ti⁴⁺≡SBP exhibited excellent comprehensive responsiveness about p H/temperature/ion.At the same time,Higuchi kinetic model can better describe the release process of IBA-Ti⁴⁺≡SBP.（3）The chelating bond-red light response valve was constructed by grafting Ti⁴⁺and PM onto SBP surface,and the red light response PM-Ti⁴⁺@SBP complex was constructed.The formation process of PM-Ti⁴⁺@SBP complex was characterized by FTIR and UV-Vis.It was found that near infrared light（NIR）stimulated the MLCT band of chelating bond-red light response valve,leading to pendimethalin（PM）release.The prepared complexes have high loading efficiency（about 55%）of PM and can effectively protect the thermal degradation of PM.Load PM data can be described by pseudo-second-order model and intragranular diffusion model,which means that Ti⁴⁺ions may provide a more compatible"adsorption site"environment for PM,and SBP can also be used as a medium for loading PM.At the same time,PM-Ti⁴⁺@SBP exhibits well NIR response and controlled release performance.