Study On The Adsorption Behavior Of Graded Structure Wood To Radionuclides

With the modern energy crisis continues to intensify,most of countries are forced to accelerate the development of clean new energy technology.As a highly efficient and clean energy source,nuclear energy is receiving more and more attention.However,a very important challenge restricting the development of nuclear energy is how to efficiently and quickly remove radionuclides.Compared with other treatment methods,the adsorption method is not only simple and efficient,but also has wide adaptability,so it is used on a large scale in real applications.In recent years,some nanomaterials and porous materials have been widely concerned by scholars because of their high specific surface area.However,nanoparticles and other particulate materials readily aggregate or settle to the bottom,and are difficult to collect during adsorption,which are limited its widely used.Since natural wood itself has the characteristics of natural hydrophilicity and abundant surface functional groups,in addition,porous wood has a graded pore structure such as macropores,mesopores,small pores,and nanopores,which allows more selective treatment of functionalized wood,functionalized wood is regarded as an ideal water treatment material.This paper aims to design a composite material with good adsorption capacity for uranium and iodine in radionuclides by functional treatment of low-cost biologically derived materials,and to explore the mechanism.The main research contents are as follows:（1）A facile strategy is used to prepares Fe@FeO core-shell NP-embedded porous wood（Fe@FeO-wood）.Fe@FeO was made by NaBH₄ reduction FeCl₃ solution into the wood matrix.The surface of wood contains a large number of hydroxyl functional groups,which can form Fe-O bonds with iron nanoparticles,so that the Fe nanoparticles are evenly distributed on the surface of the pores.This method solves the problem that iron nanoparticles with good adsorption prospects for uranium readily aggregate and are difficult to collect.The adsorption capacity can reach 353 mg/g in the simulated wastewater（100ppm）.In addition,due to the low cost and pollution-free of wood,the scalability of composite materials is possible.（2）As a MOFs material with stable structure,ZIF-8 has a good ability to capture iodine vapor due to its high specific surface area and porous features.The natural tunnel in wood provides a natural space for the passage of iodine vapor.ZIF-8 can be loaded in the wood tunnel（ZIF-8@wood）.This method can make ZIF-8 and iodine vapor contact fully,and it can increase the adsorption capacity and speed up the kinetic time.The adsorption capacity of ZIF-8@wood can reach 1.09g/g under the same experimental conditions,which is 27%higher than that of ZIF-8,and the kinetic time is shortened by 25%.Due to the non-polluting nature of the composite material,the adsorbed iodine can be decomposed at high temperature and reused.（3）Taking advantage of the high selectivity of the amidoxime group（AO）to uranium,an Amidoximated wooden solar evaporator（Ag-C-AO-wood）was designed to remove uranium from wastewater.The surface temperature rises rapidly,which speeds up the flow rate of liquid molecules in the wood tunnel and the adsorption kinetic time under light conditions.The adsorption kinetic time of Ag-C-AO-wood is 4.6 hours,which is 7 times faster than the equilibrium time of AO-wood.It has approached or even exceeded the adsorption time of some traditional carbon materials under stirring.This method is expected to replace the traditional stirring method.In addition,it has potential engineering application value.Ag-C-AO-wood can not only remove up to 80%of uranium,but also has 27%adsorption capacity for iodine ions.It is believed that functionalized wood-based materials will exert the greatest potential value in water treatment and other fields in the future.