Study On The Applications And Mechanism Of Osmotic Energy Conversion Based On The Nuclear Track Membranes

The osmotic energy between sea water and river water is considered to be a potential clean energy resource.The combination of nuclear technology and other disciplines have greatly promoted the application of nanopores in osmotic energy conversion.The nanopores prepared by ion track etching method have received great attention in the study of the osmotic energy conversion and the ion transport mechanism through the nanopores.The research topics of this dissertation are in the cross fields of nuclear technology,nanotechnology and energy technology.In this dissertation,through experiment and numerical simulation,the optimization and applications of osmotic energy conversion in the nanoporous systems are studied.We have found that the osmotic energy conversion power density of the nanofluidic system has an anomalous dependence on the channel length.The electric power generated by the nanopores first increases and then decreases as the channel length decreases,showing an abnormal Ohm-length dependence.Therefore,in order to obtain higher output power,the optimum nanopores length should be in the equilibrium region between the long nanopore resistance control region and the short nanopore ion concentration polarization control region.In addition,by studying the osmotic energy conversion phenomenon of nanoporous membranes,it is found that with the increasing of pore density,the porous nanofluidic systems can shift significantly away from the linear growth of single pore at high pore density.The increasing of power density is not a simple linear integration of single nanopore.When the pore density is high,the interaction between nanopores induces severe ion concentration polarization and becomes non-negligible,which makes the osmotic energy conversion of porous systems deviate from the liear growth of single pore.Furthermore,we proposed a general simulation method for osmotic energy conversion in porous systems.The simulated results are in good agreement with the experimental datas.It can be used to study the ion transport properties through the nanopores and provide guidance for the design of high performance nanofluidic osmotic energy conversion devices.Finally,this dissertation studies the osmotic energy conversion of ultra-thin porous membrane.The results show that the ion selectivity of the ultra-thin porous membrane is mainly affected by the surface charge on the outer membranes surface,and the length of the charged area on the outer membranes surface dominants the ion selectivity and energy conversion of the nanopores.Especially in the ultra-thin porous system with high pore density,influenced by the adjacent pores,due to the lack of an effective charged area on the outer membranes surface,the power generated by the nanopore from the ultra-thin porous system is reduced by orders of magnitude compared with single pore system.With the pore density further increasing,the overall power density of the ultra-thin porous system has instead decreased.Therefore,the highest possible pore density cannot achieve higher output power.To achieve a high output power density,we should choose a proper pore density.