Application of Ordered Biochar Functional Materials in Biomedicine and Environment

Author:Li Zuo

Supervisor:wang xiao lei

Database:Doctor

Degree Year:2019

Download:49

Pages:100

Size:6057K

Keyword:

Biomass is pyrolyzed by various thermochemical processes with little or no oxygen.A carbon-rich biochar obtained from crop residue,etc.,has been recognized as a multifunctional material for energy production and environmental restoration.In the past few decades,the applications of biochar materials in bioenergy included:bioenergy production,soil fertility enhancement,carbon sequestration,environmental remediation,etc.Based on the predecessors,this paper developed the application of sugarcane biochar and borate bioglass in bone repair,the utilization of wheat straw biochar and 3D printing technology in water purification,and the exploration of cattail stalk biochar and nano-zinc oxide materials in tooth whitening,which layed a theoretical and technical foundation for the development of biochar resource utilization.The specific work including:Firstly,inspired by the bone-like structure of sugarcane biochar,a sugarcane biochar-derived bone-like borate glass scaffold was prepared by in-situ borate glass modification.The composition of the borate glass obtained by the sol-gel method was30-5B(Si/B ratio),and both the element distribution and multilayer structure of the 3D borate glass scaffold were matched with natural bone.It is important to develop a 3D bioscaffold that matches the bone in both elemental and structural aspects.Subsequent animal implantation experiments investigated the effect of the internal structure of the borate glass scaffold on the bone repair.Experimental results showed the microstructure orientation of the implant had a significant influence on the effect(speed and accuracy)of bone repair.Then the related underlying mechanisms was preliminarily discussed.Secondly,wheat straw is an inexpensive and abundant agricultural waste.Filter core of zinc oxide-covered wheat straw biochar was prepared by in-situ surface nano-modification method.At the same time,3D printing technology was used to design and manufacture a finger-sized water purification unit to load wheat straw biochar.Each water purification unit weighs only 4 grams and is convenient to carry.Filter cores of zinc oxide-covered wheat straw biochar could reduce three main water pollutants:bacteria,organic dyes and heavy metal ions.In addition,it is worth noting that wheat straw is a flexible material that has excellent electrical conductivity after carbonization.And the flexibility and conductivity of the straw could further adjust the performance of water purification.Corresponding cell and animal experiments confirmed the biosafety of the purified water.Thirdly,compared with the traditional clinical tooth whitening agent(peroxide),zinc oxide-modified porous cattail straw biochar was developed as a new tooth whitening and antibacterial material,which not only had similar whitening effect,but also significantly reduced the damage to the enamel structure.The specific surface area of zinc oxide-modified porous cattail straw biochar was as high as 541.831 m~2/g,so the exogenous pigment and bacterial toxins close to the surface of teeth could be effectively adsorpted.In addition,it had excellent antibacterial ability.The experiments systematically evaluated the toxicity of the prepared material to human oral fibroblasts,and tested its biosafety by oral gavage in male mice.