Three-dimensional artificial transpiration for efficient solar waste-water treatment

Abstract

Solar steam generation is emerging as promising solar-energy conversion technology for potential applications in desalination, sterilization and chemical purification. Despite the recent use of photon management and thermal insulation, achieving optimum solar steam efficiency requires simultaneous minimization of radiation, convection and conduction losses without compromising light absorption. Inspired by the natural transpiration process in plants, here we report a 3D artificial transpiration device with all three components of heat loss and angular dependence of light absorption minimized, which enables over 85% solar steam efficiency under one sun without external optical or thermal management. It is also demonstrated that this artificial transpiration device can provide a complementary path for waste-water treatment with a minimal carbon footprint, recycling valuable heavy metals and producing purified water directly from waste water contaminated with heavy metal ions.

Fast‐Growing Field of Interfacial Solar Steam Generation: Evolutional Materials, Engineered Architectures, and Synergistic Applications

“…d) 3D artificial transpiration equipment (right) and traditional 2D planar transpiration equipment (left). Reproduced with permission . Copyright 2017, Oxford University Press.…”

Novel Receiver-Enhanced Solar Vapor Generation: Review and Perspectives

“…Efficient utilization of solar energy to generate the clean water from seawater and even industrial wastewater has great potential to solve the shortage of fresh water resources [115,116]. Solar desalination has become one research hotspot of solar steam generation from seawater.…”

“…When subjected to steam generation experiments, the membrane has achieved average water evaporation rates of 1.62 and 6.25 kg m −2 h −1 under 1 and 4 kW m −2 irradiance with a solar thermal conversion efficiency of up to 86.5% and 94.2%, respectively. Inspired by this transpiration process and 3D morphology of plants, Xiuqiang et al, demonstrated a 3D artificial transpiration/desalination device, composed of a 3D hollow cone absorber fabricated with graphite oxide connected with a 1D water path [115]. Reprinted with permission from [117].…”

Synthesis and Photo‐Thermal Conversion Properties of Hierarchical Titanium Nitride Nanotube Mesh for Solar Water Evaporation

“…As a transition from nanofluids to solid PTC materials, Wang et al utilized a self‐assembly process to create a free‐floating film of gold nanoparticles at the air–water interface that could pump the liquid to the open surface during liquid evaporation through capillary flow. Whereafter, Au‐dominated plasmonic metal and carbon solid PTC materials were widely researched for solar water evaporation . Most of them are double layer structured (DLS) composite materials consisting of a PTC layer and a functional layer with the properties of porosity, adiabaticity, and free‐floating to allow heat localization and continuous water supplement.…”

“…In order to simplify the structure and composition of PTC materials, Ito et al developed a multifunctional 3D porous graphene material that solved the problem of 2D flat feature and hydrophobic nature of graphene as the sole component for vapor generation. Li et al combined a 3D cone absorber of graphene oxide (GO) with a 1D water path to enhance the evaporation area and rate. Hu et al used GO‐based aerogels for efficient solar steam generation.…”