Photothermal Wood-Based Materials For Application In Water Treatment

With the development of industrial manufacturing and increasing demand of multi-activities worldwide,energy dilemma and freshwater shortage gradually turn to the restricted factors affecting sustainable development.For energy utilization,with dwindling of non-renewable fossil energy like coal,petroleum,and natural gas,more attention has been paid to environmental-friendly,efficient,and regenerative energy resources.In addition,multi energy-saving technologies have been widely considered to relieve present situation.For freshwater shortage,decreasing of freshwater reserve in inland area,water environment pollution,and present high demand consumption of seawater desalination to freshwater all deteriorate present situation.Hence,it is vital to achieve efficient seawater desalination and alleviate pollution of water environment.Based on above research background,this research is aimed to utilize wood-based materials with effective energy storage and conversion function.These materials can achieve high-efficiency utilization of clean and renewable solar energy,which promote potential solutions for current energy dilemma.Additionally,efficient utilization of solar energy in seawater desalination and oil-water separation via wood-based materials can be promising in alleviating water dilemma.Thus,this research focuses on functional wood-based materials with photothermal decoration for application in energy conversion and storage,seawater evaporation desalination,solar-assisted oil-water separation.Specific research contents are exhibited as follows:1.Design and fabrication of wood-based photothermal materials for energy conversion and storage.In this research,carbonized wood flour(CWF)functions as supporting matrix for phase change material composites(PCMC)and modified energy conversion components.These composites form multi-functional materials with property of energy conversion and storage through liquid-solid phase change process.Specifically,polyethylene glycol(PEG)is PCMC part due to its favorable phase change abilities and biocompatibility.Graphene is the basis of energy conversion benefiting from its biocompatibility and characteristic π-π conjugated lattice structure,which endow graphene function conducting photothermal conversion.Ferroferric oxide(Fe3O4)is magnetocaloric materials with magnetothermal effect in low-frequency alternating magnetic field.In-suit hydrothermal reduction is applied to fabricate reduced graphene oxide decorated with Fe3O4 nanoparticles(GNS-Fe3O4),which functions as energy conversion components.Complementally,magnetothermal effect can assist photothermal conversion to better energy conversion and storage performance,AS-prepared materials exhibit phase change latent enthalpy over 90 J/g.Favorable reservation of latent enthalpy through 100 thermogenesis cycles can be also be achieved in this research.2.Design and fabrication of functionalized wood-based materials for solar evaporation and seawater desalination.In this research,a strategy of all-wood based resources utilization is proposed.Specifically,lignin derived from delignification wastewater is recycled as carbon resources to fabricate carbon quantum dots(LCQD)via mild hydrothermal decomposition-rearrangement.Then LCQD is decorated onto surfaces of delignified wood(DW)via vacuum-assisted immersion.DW wrapped with LCQD is obtained as LCQD-DW.As-prepared materials possess abundant porous structure,channels with low-tortuosity,and photothermal effect of LCQD.These merits endow LCQD-DW high-efficiency photothermal evaporation and seawater desalination.Notably,this fabrication strategy not only maximums utilization of sustainable wood resources,but also guarantee affinity and stability between components because of their same sources.As-prepared materials can achieve 1.18 kg·m-2 evaporation with 79.5%efficiency under 1 sun illumination(65 min),which provides efficient route to environmental-friendly seawater desalination.3.Design and fabrication of functionalized wood-based materials for solar-assisted oil-water separation.In this research,Balsa wood is selectively treated through chemical removal of lignin and hemicellulose.Resulted cellulose framework can function as wood sponge(WS)with anisotropic compressibility.Surfaces of WS are modified with graphene oxide through vacuum immersion,in-suit thermal reduction and hydrophobic coating decoration.As-prepared materials can function on oil-water separation and photothermal induced high-viscous crude-oil adsorption.As-prepared materials can efficiently collect high-viscous crude-oil benefiting from its photothermal effects,which is achieved through in-situ solar induced photothermal thermogenesis and subsequent lower viscosity of crude oil.This material can also treat common heavy and light oil pollutants through passive adsorption and active pumping-assisted collection.As-prepared materials can rapidly increase temperature of crude oil over 60℃ and lower its viscosity,which can achieve efficient collection within 300 s.After 10 cycles of adsorption-compression,materials can still induce crude-oil adsorption efficiently.This research focuses on wood-based materials with multi functions to alleviate various application demands.Strategies employed in this research fully utilize fundamental structure and components of wood-based materials,which maximums utilization of particular property of wood-based materials.Results of this research provide potential alleviates for present energy dilemma and freshwater shortage situation.