Preparation And Performance Research Of Wood-based Solar Interface Evaporation Materials

With economic development and population increase,freshwater resources are becoming increasingly scarce.In recent years,the use of solar interface evaporation technology to treat saltwater and wastewater to obtain freshwater has attracted wide attention from researchers.Compared with traditional freshwater production methods,solar interface evaporation technology has the characteristics of environmental friendliness,low cost,and adjustable scale.As a common natural material,wood has the advantages of environmental friendliness,renewable,high mechanical strength,high hydrophilicity,low density,low thermal conductivity,and low cost.It has great application potential in the field of solar interface water evaporation.Therefore,this thesis uses wood as the substrate of the evaporator to carry out the following researches:（1）Using wood as a substrate,the polypyrrole nanotube-wood composite（PPy＿NT-wood）was successfully prepared through that polypyrrole nanotubes were grown in situ on the surface of the wood by the self-degradable template method.PPy＿NT-wood exhibited excellent light absorption capacity（～99%）across the full solar spectrum range of 300 to 2500 nm.It showed a high evaporation rate of 1.03kg·m^-2·h^-1 and an evaporation efficiency of 66.2%under 1 sun.With the good hydrophilicity and bimodal porous structure of composite,PPy＿NT-wood showed excellent salt rejection ability.Meanwhile,the concentration of the main ions in the water,which was collected after the South China Sea seawater was desalinated by this composite,was significantly reduced.PPy＿NT-wood also showed excellent purification ability in treating Yellow River water,heavy metal wastewater,wastewater with different p H,and dyeing wastewater.Therefore,PPy＿NT-wood had broad application prospects in the field of solar interface evaporation and provided a guidance for the application of polypyrrole and even conjugated polymers with different morphologies in this field.（2）In the actual application process,the solar interface evaporation material may be fouled by the oil-based pollutants in the oily wastewater,resulting in a significant drop in its evaporation performance.At present,wood-based solar interface evaporation materials were rarely optimized and designed for oily wastewater.In order to improve the ability of wood-based materials to treat oily wastewater,we developed an anti-oil-fouling wood-derived aerogel as solar interface evaporation material by partially removing lignin and hemicellulose in wood and using carbon nanotubes as photothermal materials.This material,which used the micropores on the wood pipe as the water transmission channel,presented superhydrophilicity and underwater superoleophobicity.The evaporation rate of 1.17 kg·m^-2·h^-1 was achieved in the oil-in-water emulsion under 1 sun,which was only 3.3%lower than that in pure water.After the emulsion was purified,the value of TOC in the water was dropped from 6309 ppm to 38 ppm,and the removal efficiency was as high as 99.4%.This anti-oil-fouling material also exhibited good cycle performance in the oil-in-water emulsion.In addition,the material had good effects in seawater desalination,treatment of heavy metal wastewater,and dyeing wastewater.The preparation method of the anti-oil-fouling wood-derived aerogel solar interface evaporation material was simple,mature,and easy to scale up,this work opened up a new avenue for the wood-based solar interface evaporation material to treat oily wastewater.（3）Because the preparation of wood-based solar interface evaporation materials needed high-temperature conditions or chemical reagents,there were safety risks and environmental risks.In order to pursue a wood-based solar interface evaporation material with a safer and greener preparation process,we chose natural melanin nanoparticles in cuttlefish juice as the photothermal material,and then an all-natural and all-biomass cuttlefish juice-wood composite was constructed successfully through anchoring natural melanin nanoparticles on the wood by a simple“vacuum impregnation and drying”process.The cuttlefish juice-wood composite exhibited a high absorbance of 98.28%in the wavelength range of 300-1000 nm.Under 1,2,3,and 5 sun,the composite exhibited evaporation rates of 0.88,1.81,2.72,and 4.59kg·m^-2·h^-1,corresponding to evaporation efficiency of 56.2,58.92,59.91,and 60.78%,respectively.Meanwhile,it could be also used for seawater desalination,heavy metal wastewater treatment,and dyeing wastewater treatment,which showed good treatment effects.Cuttlefish juice-wood composite had the advantages of environmental friendliness,low process complexity and low preparation temperature,which provided a new idea for the development of safe and environmentally-friendly solar interface evaporation materials.