With the development of the industry,water pollution and shortage have become serious global problems.Owing to the abundance of seawater storage on earth,efficient solar-driven evaporation is a promising approach to r...With the development of the industry,water pollution and shortage have become serious global problems.Owing to the abundance of seawater storage on earth,efficient solar-driven evaporation is a promising approach to relieve the freshwater shortage.The solar-driven evaporation has attracted tremendous attention due to its potential application in the seawater desalination and wastewater treatment fields.Also,the solar-driven evaporation efficiency can be enhanced by designing both solar absorbers and structures.Up to now,many strategies have been explored to achieve high solar-driven evaporation efficiency,mainly including the selection of photothermal conversion materials and structure optimization.In this review,the solar absorbers,structural designs,and energy management are proposed as the keys for high performance solar-driven evaporation systems.We report four kinds of solar absorbers based on different photothermal conversion mechanisms,substrate structure designs,and energy management methods for the purpose to achieve high conversion efficiency.And we also systematically investigate the available salt-rejections strategies for seawater desalination.This review aims to summarize the current development of efficient solar-driven evaporation systems and provide insights into the photothermal conversion materials,structural designs,and energy management.Finally,we propose the perspectives of the salt-rejection technologies for seawater desalination.展开更多
Solar steam generation(SSG)is widely regarded as one of the most sustainable technologies for seawater desalination.However,salt fouling severely compromises the evaporation performance and lifetime of evaporators,lim...Solar steam generation(SSG)is widely regarded as one of the most sustainable technologies for seawater desalination.However,salt fouling severely compromises the evaporation performance and lifetime of evaporators,limiting their practical applications.Herein,we propose a hierarchical salt-rejection(HSR)strategy to prevent salt precipitation during long-term evaporation while maintaining a rapid evaporation rate,even in high-salinity brine.The salt diffusion process is segmented into three steps—insulation,branching diffusion,and arterial transport—that significantly enhance the salt-resistance properties of the evaporator.Moreover,the HSR strategy overcomes the tradeoff between salt resistance and evaporation rate.Consequently,a high evaporation rate of 2.84 kg m^(-2) h^(-1),stable evaporation for 7 days cyclic tests in 20 wt%NaCl solution,and continuous operation for 170 h in natural seawater under 1 sun illumination were achieved.Compared with control evaporators,the HSR evaporator exhibited a>54%enhancement in total water evaporation mass during 24 h continuous evaporation in 20 wt%salt water.Furthermore,a water collection device equipped with the HSR evaporator realized a high water purification rate(1.1 kg m^(-2) h^(-1)),highlighting its potential for agricultural applications.展开更多
Membrane distillation （MD） is a thermal, vapor-driven transportation process through micro porous hydrophobic membranes that is increasingly being applied to seawater and brine desalination processes. Two types of h...Membrane distillation （MD） is a thermal, vapor-driven transportation process through micro porous hydrophobic membranes that is increasingly being applied to seawater and brine desalination processes. Two types of hydrophobic microporous polyethersulfone fiat sheet membranes, namely, annealed polyethersulfone and a polyethersulfone/tetraethoxysilane （PES/TEOS） blend were prepared by a phase inversion process. The membranes were characterized and their performances were investigated using the vacuum membrane distillation of an aqueous NaCI solution. The performances of the prepared membranes were also compared with two commercially available hydrophobic membranes, polyte- trafluorethylene and polyvinylidene fluoride. The influence of operational parameters such as feed temperature （25-65 ℃）, permeate vacuum pressure （200 800 mbar）, feed flow rate （8-22 mL/s） and feed salt concentration （3000 to 35000 mg/L） on the MD permeation flux were investigated for the four membranes. The hydrophobic PES/TEOS membrane had the highest salt rejection （99.7%） and permeate flux （86 kg/（m^2 -h）） at 65 ℃, with a feed of 7000 ppm and a pressure of 200 mbar.展开更多
基金This work was financially supported by MOE Tier 1(A-0009304-01-00)of Singapore.
文摘With the development of the industry,water pollution and shortage have become serious global problems.Owing to the abundance of seawater storage on earth,efficient solar-driven evaporation is a promising approach to relieve the freshwater shortage.The solar-driven evaporation has attracted tremendous attention due to its potential application in the seawater desalination and wastewater treatment fields.Also,the solar-driven evaporation efficiency can be enhanced by designing both solar absorbers and structures.Up to now,many strategies have been explored to achieve high solar-driven evaporation efficiency,mainly including the selection of photothermal conversion materials and structure optimization.In this review,the solar absorbers,structural designs,and energy management are proposed as the keys for high performance solar-driven evaporation systems.We report four kinds of solar absorbers based on different photothermal conversion mechanisms,substrate structure designs,and energy management methods for the purpose to achieve high conversion efficiency.And we also systematically investigate the available salt-rejections strategies for seawater desalination.This review aims to summarize the current development of efficient solar-driven evaporation systems and provide insights into the photothermal conversion materials,structural designs,and energy management.Finally,we propose the perspectives of the salt-rejection technologies for seawater desalination.
基金support provided by the Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park Project(HZQB-KCZYB-2020030)the Research Grants Council of Hong Kong(Project No:AoE/M-402/20.)+1 种基金the Open Project of Yunnan Precious Metals Laboratory Co.,Ltd(YPML-2023050248)the Hong Kong Innovation and Technology Commission via the Hong Kong Branch of National Precious Metals Material Engineering Research Center.
文摘Solar steam generation(SSG)is widely regarded as one of the most sustainable technologies for seawater desalination.However,salt fouling severely compromises the evaporation performance and lifetime of evaporators,limiting their practical applications.Herein,we propose a hierarchical salt-rejection(HSR)strategy to prevent salt precipitation during long-term evaporation while maintaining a rapid evaporation rate,even in high-salinity brine.The salt diffusion process is segmented into three steps—insulation,branching diffusion,and arterial transport—that significantly enhance the salt-resistance properties of the evaporator.Moreover,the HSR strategy overcomes the tradeoff between salt resistance and evaporation rate.Consequently,a high evaporation rate of 2.84 kg m^(-2) h^(-1),stable evaporation for 7 days cyclic tests in 20 wt%NaCl solution,and continuous operation for 170 h in natural seawater under 1 sun illumination were achieved.Compared with control evaporators,the HSR evaporator exhibited a>54%enhancement in total water evaporation mass during 24 h continuous evaporation in 20 wt%salt water.Furthermore,a water collection device equipped with the HSR evaporator realized a high water purification rate(1.1 kg m^(-2) h^(-1)),highlighting its potential for agricultural applications.
文摘Membrane distillation （MD） is a thermal, vapor-driven transportation process through micro porous hydrophobic membranes that is increasingly being applied to seawater and brine desalination processes. Two types of hydrophobic microporous polyethersulfone fiat sheet membranes, namely, annealed polyethersulfone and a polyethersulfone/tetraethoxysilane （PES/TEOS） blend were prepared by a phase inversion process. The membranes were characterized and their performances were investigated using the vacuum membrane distillation of an aqueous NaCI solution. The performances of the prepared membranes were also compared with two commercially available hydrophobic membranes, polyte- trafluorethylene and polyvinylidene fluoride. The influence of operational parameters such as feed temperature （25-65 ℃）, permeate vacuum pressure （200 800 mbar）, feed flow rate （8-22 mL/s） and feed salt concentration （3000 to 35000 mg/L） on the MD permeation flux were investigated for the four membranes. The hydrophobic PES/TEOS membrane had the highest salt rejection （99.7%） and permeate flux （86 kg/（m^2 -h）） at 65 ℃, with a feed of 7000 ppm and a pressure of 200 mbar.
