Biomass-derived Porous Carbon By Chemical Activation For Adsorption And Releasing Of Cercaricidal Drug

Schistosoma cerariae is the only period for the human infection.To effectively breaking the infection route of Schistosomiasis,we need control the Schistosoma cerariae.The existing cercaricidal drugs have some drawbacks such as the short time of drug effect,so we need to develop the long-acting and sustained-release drug.Biomass carbon materials could be an excellent platform to loading anti-cerariae drug due to friendly environmental and low-cost properties.The carbon materials prepared by directly pyrolysis possessed low specific surface and small pore volume,which result in the low adsorption volume of drug.In this thesis,pyrolysis method of chemical activation was introduced to obtain high specific surface area and different porous type carbon materials.And then,the different biomass carbon materials were used for investigate the adsorption and releasing of cercaricidal drugs.1.Synthesis and characterization of biomass carbon materialsbiomass materials were choose as starting material,the surface morphology,functional groups,surface elements?carbon,oxygen,nitrogen?,and specific surface area of the carbonized materials were characterized to investigate the influence of different synthesis methods.The results showed that the charring yields of the biomass were decreased when activation reagents were add.All carbon materials prepared by method of chemical activation contain hydroxyl,ether,carbonyl and aromatic groups.Carbon materials activated by HNO₃ could have high percentages of surface nitrogen element.Activating with KOH can increase percentages of surface oxygen for bamboo carbon materials,and the percentages of surface oxygen increased with increasing of KOH's ratio.Activating with KOH and HNO₃ decreased the percentages of surface oxygen of poplar carbon.The nitrogen adsorption data indicated that the method of chemical activation increase specific surface area for all kind of carbon materials.Bamboo carbon material by activation of KOH was microporous carbon,which contain high specific surface area.All kind of carbon materials by activation of Na₂CO₃ were mesoporous carbon.The bamboo which was pyrolyzed under 600 ⁰C has the largest specific surface.The poplar and locust pyrolyzed under800 ⁰C has the largest specific surface.2.The adsorption and releasing of cercaricidal drug of carbon materialsThe adsorption and releasing process of cercaricidal drug in different pore structure of carbon materials?Zk1,Yk1,Zn2 and Zh2?were studied.The results showed that increasing the specific surface area of the carbon materials was beneficial to improve the adsorption quantity of drugs.Through the research of adsorption dynamics,the adsorption process of carbon materials to cercaricidal drug was conformed to the secondary reaction kinetics.Through the fitting of adsorption isotherm,it is found that the adsorption of four kinds of carbon materials to drugs was homogeneous.The drug releasing experiments indicating that carbon materials with a high number of microporous had a long drug releasing time,but the drug releasing rate is low.However,the carbon materials with a high number of mesoporous had a short drug releasing time but a high drug releasing rate.The experimental results of killing cerariae suggested that the solution containing cercaricidal drugs released from four carbon materials for 30 minutes was effective to kill the cerariae.3.Floating properties and modification of biomass carbon materialsAiming to match the floating characteristic of Schistosoma cerariae,we investigated the floating properties of the carbon materials of Zk1,Yk1,Zn2 and Zh2.The results showed that the carbon materials synthesized by the activation of KOH and Na₂CO₃ have strong hydrophilic property,but the carbon materials made by the activation of HNO₃ had hydrophobic property.Furthermore,the paraffin wax was used to improve the water contact angle of the carbon materials.The modification results indicated that the floating properties of four kinds of carbon materials with the modification of the paraffin wax was improved.Meanwhile,the carbon material Zn2modified by the paraffin wax solution of 1 mg/mL and the carbon materials Zk1,Zh2 and Yk1 that processed by the paraffin wax solution of 3 mg/mL can float on the water over 30 days.