Fabrication of stable MWCNT bucky paper for solar-driven interfacial evaporation by coupling c-ray irradiation with borate crosslinking

Herein,we report a facile solution process for preparing multi-walled carbon nanotube(MWCNT)bucky paper for solar-driven interfacial water evaporation.This process involves vacuum filtrating a dispersion of MWCNTs that was modified by polyvinyl alcohol(PVA)under c-ray irradiation on a cellulose acetate microporous membrane,followed by borate crosslinking.Fourier transform infrared spectroscopy,Raman spectroscopy,and thermogravimetry confirmed the success of PVA grafting onto MWCNTs and borate crosslinking between modified MWCNT nanoyarns.The as-prepared crosslinked MWCNT bucky papers(BBP membranes)were used as a solar absorber,by placing them on a paper-wrapped floating platform,for interfacial water evaporation under simulated solar irradiation.The BBP membranes showed good water tolerance and mechanical stability,with an evaporation rate of 0.79 kg m^(-2)h^(-1)and an evaporation efficiency of 56%under 1 sun illumination in deionized water.Additionally,the BBP membranes achieved an evaporation rate of 0.76 kg m^(-2)h^(-1)in both NaCl solution(3.5 wt%)and sulfuric acid solution(1 mol L-1),demonstrating their impressive applicability for water reclamation from brine and acidic conditions.An evaporation rate of 0.70 kg m-2 h-1(very close to that from deionized water)was obtained from the solar evaporation of saturated NaCl solution,and the BBP membrane exhibited unexpected stability without the inference of salt accumulation on the membrane surface during long-term continuous solar evaporation.

Harnessing overlapped temperature-salinity gradient in solar-driven interfacial seawater evaporation for efficient steam and electricity generation

Solar-driven interfacial water evaporation(SIWE)offers a superb way to leverage concentrated solar heat to minimize energy dissipation during seawater desalination.It also engenders overlapped temperaturesalinity gradient(TSG)between water-air interface and adjacent seawater,affording opportunities of harnessing electricity.However,the efficiency of conventional SIWE technologies is limited by significant challenges,including salt passivation to hinder evaporation and difficulties in exploiting overlapped TSG simultaneously.Herein,we report self-sustaining hybrid SIWE for not only sustainable seawater desalination but also efficient electricity generation from TSG.It enables spontaneous circulation of salt flux upon seawater evaporation,inducing a self-cleaning evaporative interface without salt passivation for stable steam generation.Meanwhile,this design enables spatial separation and simultaneous utilization of overlapped TSG to enhance electricity generation.These benefits render a remarkable efficiency of90.8%in solar energy utilization,manifesting in co-generation of solar steam at a fast rate of 2.01 kg m^(-2)-h^(-1)and electricity power of 1.91 W m^(-2)with high voltage.Directly interfacing the hybrid SIWE with seawater electrolyzer constructs a system for water-electricity-hydrogen co-generation without external electricity supply.It produces hydrogen at a rapid rate of 1.29 L h^(-1)m^(-2)and freshwater with 22 times lower Na+concentration than the World Health Organization(WHO)threshold.

Nano-enabled solar driven-interfacial evaporation:Advanced design and opportunities

Solar-driven interfacial evaporation(SDIE)is emerging as a promising pathway to solving the worldwide water shortage and water pollution.Nanomaterials(e.g.,plasmonic metals,inorganic/organic semiconductors,and carbon nanomaterials)and related nanochemistry have attracted increasing attention for the solar-to-vapor process in terms of broadband absorption,electronic structure adjustment,and surface/interface chemistry manipulation.Furthermore,the assembly of nanomaterials can contribute to the mass transfer,heat management,and enthalpy regulation of water during solar evaporation.To date,numerous nano-enabled materials and structures have been developed to improve the solar absorption,heat management(i.e.,heat confinement and heat transfer),and water management(i.e.,activation,evaporation,and replenishment).In this review,we focus on a systematical summary about the composition and structure engineering of nanomaterials in SDIE,including size and morphology effects,nanostructure optimizations,and structure-property relationship decoupling.This review also surveys recent advances in nanochemistry(e.g.,preparation chemistry and structural chemistry)deployed to conceptual design of nanomaterials.Finally,the key challenges and future perspectives of nanomaterials for solar evaporation are overviewed.This review aims at providing guidance for the design and construction of nanomaterials for high-efficiency SDIE on the basis of the aspects of materials science and chemical engineering.

Directionally tailoring micro-nano hierarchical tower structured Mn_(0.6)Ni_(1.4)Co_(2)O_(y) toward solar interfacial evaporation

Solar interfacial evaporation has been considered as a promising method to alleviate fresh water re-sources shortage.The shortage of freshwater resources requires advanced materials that can accelerate the evaporation of water by the sun.However,the simple structure of photothermal materials are vitally restricted by finite light absorption.Herein,this work presents a strategy for the synthesis of a spinel-type micro-nano hierarchical tower structure solar absorbent(Mn_(0.6)Ni_(1.4)Co_(2)O_(y))with the low forbidden band(=1.56 eV)and high absorption(97.88%).The products show great potential in solar-thermal energy conversion by creating a trapping effect.The prepared solar absorbent and epoxy resin are evenly mixed and then fully immersed in polyurethane(PU)sponge for water evaporation.The hydrophilic and porous Mn_(0.6)Ni_(1.4)Co_(2)O_(y)@PU sponge can quickly deliver water upwards,suppress the heat loss,and concentrate the absorbed heat on the evaporation of water.The products exhibited an excellent evaporation rate of 2.261 kg m^(-2) h^(-1) and an impressive evaporation efficiency of 156%under a single sun exposure.Besides,the samples also can maintain the stability and recycling performance for a long time.These findings show that Mn_(0.6)Ni_(1.4)Co_(2)O_(y) have great application prospects in the solar interfacial evaporation.

Micro–Nano Water Film Enabled High‑Performance Interfacial Solar Evaporation

Interfacial solar evaporation holds great promise to address the freshwater shortage.However,most interfacial solar evaporators are always filled with water throughout the evaporation process,thus bringing unavoidable heat loss.Herein,we propose a novel interfacial evaporation structure based on the micro–nano water film,which demonstrates significantly improved evaporation performance,as experimentally verified by polypyrrole-and polydopamine-coated polydimethylsiloxane sponge.The 2D evaporator based on the as-prepared sponge realizes an enhanced evaporation rate of 2.18 kg m^(−2)h^(−1)under 1 sun by fine-tuning the interfacial micro–nano water film.Then,a homemade device with an enhanced condensation function is engineered for outdoor clean water production.Throughout a continuous test for 40 days,this device demonstrates a high water production rate(WPR)of 15.9–19.4 kg kW^(−1)h^(−1)m^(−2).Based on the outdoor outcomes,we further establish a multi-objective model to assess the global WPR.It is predicted that a 1 m^(2)device can produce at most 7.8 kg of clean water per day,which could meet the daily drinking water needs of 3 people.Finally,this technology could greatly alleviate the current water and energy crisis through further large-scale applications.

Janus membrane with enhanced interfacial activation for solar evaporation

Low solar spectrum coverage,high evaporation enthalpy,and undesired salt deposition severely limited the solar-driven interfacial evaporation technology for further sewage purification and seawater desalination.To overcome these problems,we designed an amphiphilic Janus-structured polyaniline(PANI)/ZrC/cellulose acetate(CA)(J-PZCA) membrane.Firstly,the interfacial interaction between PANI and ZrC enhances the photoabsorption and photothermal conversion efficiency.Secondly,low thermal conductivity reduces the heat lost at the interface.Most importantly,ZrC could facilitate interfacial activation,which weakens the intermolecular forces of water by affecting the hydrogen bond.Under 1 solar irradiation(1 sun),the composite membrane exhibits a high evaporation rate of 1.31 kg m^(-2)h^(-1) and an excellent efficiency of 79.4%.In addition,the sewage purification and seawater desalination experiments reveal a remarkable purification capability of J-PZCA membrane.Especially for the treatment of high-concentration salt solution,it realizes a long-term stable evaporation performance due to the excellent salt deposition resistance.Therefore,the J-PZCA membrane constructed in this study provides a new perspective for the design of efficient interfacial evaporation devices.

Boosting extraction of Pb in contaminated soil via interfacial solar evaporation of multifunctional sponge

Interfacial solar water evaporation is a reliable way to accelerate water evaporation and contaminant remediation.Embracing the recent advance in photothermal technology,a functional sponge was prepared by coating a sodium alginate(SA)impregnated sponge with a surface layer of reduced graphene oxide(rGO)to act as a photothermal conversion medium and then subsequently evaluated for its ability to enhance Pb extraction from contaminated soil driven by interfacial solar evaporation.The SA loaded sponge had a Pb adsorption capacity of 107.4 mg g^(-1).Coating the top surface of the SA sponge with rGO increased water evaporation performance to 1.81 kg m^(-2)h^(-1)in soil media under one sun illumination and with a wind velocity of 2 m s^(-1).Over 12 continuous days of indoor evaporation testing,the Pb extraction efficiency was increased by 22.0%under 1 sun illumination relative to that observed without illumination.Subsequently,Pb extraction was further improved by 48.9%under outdoor evaporation conditions compared to indoor conditions.Overall,this initial work shows the significant potential of interfacial solar evaporation technologies for Pb contaminated soil remediation,which should also be applicable to a variety of other environmental contaminants.

Interfacial Evaporation of Falling Liquid Films with Wall Heating

The interfacial evaporation of falling water films with wall heating was experimentally studied and analyzed. The results presented in this paper showed that the capillary induced interfacial evaporation played an important role in heat transfer of a falling liquid film. It would be independent of the wall heat flux and somewhat lower than that without wall heating for impure fluids such as water air system. The thermodynamic analysis conducted gave a theoretical basis for the experimental observations. The effective capillary radius was correlated with the mass flow rate. The experimental results and analysis showed that the interfacial evaporation should be taken into account in the study of falling liquid film heat transfer.

The effect of interfacial evaporation on heat and mass transfer of falling liquid film

Analysis of experimental data and estimation of the order of magnitude for interfacial mass diffusion have demonstrated that considerable excess evaporation exists on the free interface of falling liquid film, and that the capillary pressure caused by surface tension is the driving force of this excess interfacial evaporation, which we called the “capillarity-induced interfacial evaporation”. By correlating the experimental data, an empirical expression of the effective capillary radius, r\-e, is obtained with which the evaporative rate formula we derived and reported previously has been modified to improve the prediction of the critical heat flux for film breakdown. Comparisons with the available predicting models show that our modified equation can predict the experimental results with much lower relative deviation.

Biomass-enhanced Janus sponge-like hydrogel with salt resistance and highstrength for efficient solar desalination

Interfacial solar-driven evaporation technology shows great potential in the field of industrial seawater desalination, and the development ofefficient and low-cost evaporation materials is key to achieving large-scale applications. Hydrogels are considered to be promising candidates;however, conventional hydrogel-based interfacial solar evaporators have difficulty in simultaneously meeting multiple requirements, including ahigh evaporation rate, salt resistance, and good mechanical properties. In this study, a Janus sponge-like hydrogel solar evaporator (CPAS) withexcellent comprehensive performance was successfully constructed. The introduction of biomass agar (AG) into the polyvinyl alcohol (PVA)hydrogel backbone reduced the enthalpy of water evaporation, optimized the pore structure, and improved the mechanical properties. Meanwhile, by introducing hydrophobic fumed nano-silica aerogel (SA) and a synergistic foaming-crosslinking process, the hydrogel spontaneouslyformed a Janus structure with a hydrophobic surface and hydrophilic bottom properties. Based on the reduction of the evaporation enthalpy andthe modulation of the pore structure, the CPAS evaporation rate reached 3.56 kg m^(-2) h^(-1) under one sun illumination. Most importantly, owingto the hydrophobic top surface and 3D-interconnected porous channels, the evaporator could work stably in high concentrations of salt-water(25 wt% NaCl), showing strong salt resistance. Efficient water evaporation, excellent salt resistance, scalable preparation processes, and low-costraw materials make CPAS extremely promising for practical applications.

Highly efficient three-dimensional solar evaporator for zero liquid discharge desalination of high-salinity brine

Solar-driven interfacial evaporation is a promising technology for freshwater production from seawater,but salt accumulation on the evaporator surface hinders its performance and sustainability.In this study,we report a simple and green strategy to fabricate a three-dimensional porous graphene spiral roll(3GSR)that enables highly efficient solar evaporation,salt collection,and water production from near-saturated brine with zero liquid discharge(ZLD).The 3GSR design facilitates energy recovery,radial brine transport,and directional salt crystallization,thereby resulting in an ultrahigh evaporation rate of 9.05 kg m^(-2) h^(-1)6 in 25 wt%brine under 1-sun illumina-tion for 48 h continuously.Remarkably,the directional salt crystallization on its outer surface not only enlarges the evaporation area but also achieves an ultrahigh salt collection rate of 2.92 kg m^(-2) h^(-1),thus enabling ZLD desalination.Additionally,3GSR exhibits a record-high water production rate of 3.14 kg m^(-2) h^(-1) in an outdoor test.This innovative solution offers a highly efficient and continuous solar desalination method for water production and ZLD brine treatment,which has great implications for addressing global water scarcity and environmental issues arising from brine disposal.

A Biomass-Based Hydrogel Evaporator Modified Through Dynamic Regulation of Water Molecules:Highly Efficient and Cost-Effective

Solar-driven hydrogel evaporator used for water purification demonstrates great potential in seawater desalination and domestic sewage treatment.However,much uncertainty still exists about the most efficient design to obtain cost-effective drinkable water.In this paper,a natural rich biomass Nicandra physalodes(Linn.)Gaertn.polysaccharide was introduced into the polyvinyl alcohol network to control the water distribution during evaporation and build a low-cost hybrid hydrogel solar evaporator with a total material cost of$7.95 m^(−2).The mixed evaporator works stably in a long-span acid–base range(pH 1–14)and salinity range(0–320 g kg^(−1)).Its daily water purification capacity can reach 24.4 kg m^(−2)with a water purification capacity of 3.51 kg m^(−2)h^(−1)under sunlight.This paper provides a new possibility for a highly efficient and cost-effective water desalination system with guaranteed water quality by focusing on the dynamic regulation of water molecules at the evaporation interface.

Recent strategies for constructing efficient interfacial solar evaporation systems

Interfacial solar evaporation(ISE)is a promising technology to relieve worldwide freshwater shortages owing to its high energy conversion efficiency and environmentally sustainable potential.So far,many innovative materials and evaporators have been proposed and applied in ISE to enable highly controllable and efficient solar-to-thermal energy conversion.With rational design,solar evaporators can achieve excellent energy management for lowering energy loss,harvesting extra energy,and efficiently utilizing energy in the system to improve freshwater production.Beyond that,a strategy of reducing water vaporization enthalpy by introducing molecular engineering for water-state regulation has also been demonstrated as an effective approach to boost ISE.Based on these,this article discusses the energy nexus in two-dimensional(2D)and three-dimensional(3D)evaporators separately and reviews the strategies for design and fabrication of highly efficient ISE systems.The summarized work offers significant perspectives for guiding the future design of ISE systems with efficient energy management,which pave pathways for practical applications.

Self-Healing Hydrophilic Porous Photothermal Membranes for Durable and Highly Efficient Solar-Driven Interfacial Water Evaporation

It is highly desirable to develop a solar-driven interfacial water evaporatorwith a self-healing ability and high-efficiency water evaporation performance for water distillation and desalination;however,this process is considerably challenging.Herein,by exploiting the advantages of a self-healing hydrophilic polymer,a self-healing hydrophilic porous photothermal(SHPP)membrane was fabricated by curing a mixture of the polymer,carbon black,and NaCl,followed by removal of the NaCl from water.Since the SHPP membrane could serve as a photothermal layer and water transportation channel simultaneously,a solar-driven interfacial evaporator could be fabricated readily by assembling the SHPP membrane with polyethylene foam.We have shown that the SHPP membrane-based evaporator exhibited a water evaporation rate of 1.68 kg m^(−2) h^(−1) and an energy efficiency of 97.3%.These values are superior to those obtained using solar-driven interfacial evaporators with self-healing capability.Notably,by hydrogen bonds reformation between the fracture surfaces,the SHPP membrane could regain its structural integrity after breaking,making the SHPPmembrane-based evaporator the first to heal entirely and repeatedly from physical damage to sustain itswater evaporation capacity.Therefore,the potential of using SHPP membranes to develop stable,long-last ing,andhigh-efficiency solar-driven interfacial water evaporators is highlighted.

Polymer Modified Banana Pseudo Stem-based Interfacial Solar-driven Evaporation System

Interfacial solar-driven evaporation technique is an environmental friendly and cost-effective advanced approach for water purification using solar energy.Free energy sources are effectively utilized using the structural design of evaporators and functional materials.In this work,we have fabricated a solar-driven interfacial evaporation device with Banana Pseudo Stem(BPS)and a photothermal layer made up of PVA PDMS Carbon(PPC)is attached to it.High evaporation rate of 2.03 kg m^(−2) h^(−1) is achieved by the system under 1 sun illumination.Heat localization on interfacial surface,reflectance of photothermal layer,presence of micro-fluidic channels in BPS were studied using IR imaging,UV-DRS and SEM characterization techniques,respectively.Effective localization of interfacial temperature around 53℃ and very low reflectance of photothermal layer substantiates high photothermal conversion efficiency of the device.The complete purification of water containing high concentration of Rhodamine-B dye using BPS is a novel and simple approach for water purification.This is an eco-friendly,cost-efficient novel approach in fabrication of interfacial solar-driven evaporation system with high evaporation rate for purification of water containing high concentration of organic dye.

Photothermal properties of Cu@polycarbonate composites with strong localized surface plasmon resonances

Copper is relatively low cost and highly abundant compared with the well-studied noble metals such as gold and silver.However,the poor plasmonic and high susceptibility towards oxidation limit the study of its optical properties and applications as well.Herein,copper nanoparticles@polycarbonate(Cu@PC)composites were prepared by using a facile one-step solvothermal method.The Cu@PC composites have strong localized surface plasmon resonances(LSPR)due to that the PC shell can induce the particles to form many-particles system with different particle numbers,which not only lead to overlap and hybridize of the LSPR modes,but also shift the LSPR away from the interband transitions,and the PC layer also prevents the oxidation of Cu nanoparticles.The photothermal conversion efficiency of Cu@PC composites reaches 41.1%under 808 nm continuous wave(CW)laser irradiation which is higher than previously reported Cu nanomaterials that have been reported.Meanwhile,the composites also have high photothermal stability.Moreover,interfacial evaporator is prepared by assembling the Cu@PC composites on scouring sponge as light absorption layer which has>92.8%absorption in entire solar spectrum range.Its seawater evaporation rate is 3.177 kg·m^(-2)·h^(-1)with a E_(evaporator)/E_(water)of 5.2.The high evaporation rate interfacial evaporator with low cost,simple,and scalable approach shows great application value in the field of photothermal evaporation.

More from less:improving solar steam generation by selectively removing a portion of evaporation surface

Using minimal photothermal material to achieve maximum evaporation rate is extremely important for practical applications of interfacial solar evaporation technology.In this work,we found that with the increase in the size of evaporation surfaces,the evaporation rate decreased.Both experimental and numerical simulation results confirmed that when the evaporation surface size increased,the middle portion of the evaporation surface acted as a‘‘dead evaporation zone”with little contribution to water evaporation.Based on this,the middle portion of the evaporation surface was selectively removed,and counterintuitively,both the evaporation rate and vapor output were increased due to the reconfigured and enhanced convection above the entire evaporation surface.As such,this work developed an important strategy to achieve a higher evaporation rate and increased vapour output while using less material.

Recent innovations in 3D solar evaporators and their functionalities

Interfacial solar evaporation(ISE)has emerged as a promising technology to alleviate global water scarcity via energy-efficient purification of both wastewater and seawater.While ISE was originally identified and developed during studies of simple double-layered two-dimensional(2D)evaporators,observed limitations in evaporation rate and functionality soon led to the development of three-dimensional(3D)evaporators,which is now recognized as one of the most pivotal milestones in the research field.3D evaporators significantly enhance the evaporation rates beyond the theoretical limits of 2D evaporators.Furthermore,3D evaporators could have multifaceted functionalities originating from various functional evaporation surfaces and 3D structures.This review summarizes recent advances in 3D evaporators,focusing on rational design,fabrication and energy nexus of 3D evaporators,and the derivative functions for improving solar evaporation performance and exploring novel applications.Future research prospects are also proposed based on the in-depth understanding of the fundamental aspects of 3D evaporators and the requirements for practical applications.

The coral-inspired steam evaporator for efficient solar desalination via porous and thermal insulation bionic design

The solar-driven interfacial evaporation(SIE)technology shows great prospects in seawater desalination and sewage treatment,but it is unable to obtain highly efficient and high-quality clean nontoxic water at low cost.Here,a novel biodegradable hydrogel-based solar evaporator(BBH-L)with a bionic coral structure taking Chinese ink as the solar absorber was developed.This evaporator consists of chitosan/polyvinyl alcohol hydrogel and a loofah substrate.The average evaporation rate and efficiency of BBH-L reach 4.37 kg/(m^(2)·h)and 98.2%,respectively,under one sun illumination(1 kW/m^(2)),which are attributed to its excellent thermal localization and water transporting abilities.Meanwhile,high salt resistance enables BBH-L to achieve efficient desalination and purification of other unconventional water.Heavy metal ions in seawater can be effectively removed by chelation and forming hydrogen bonds in hydrogels.This study is anticipated to provide new possibilities to enhance evaporation performance and reduce the costs of water treatment systems.

用于高性能太阳能界面蒸发的织物交错复合水凝胶

二维织物材料已广泛应用于太阳能界面蒸发,然而织物基太阳能蒸发器要实现吸光材料与纤维之间的强相互作用,高效的输水能力,优异的脱盐性能和高蒸发率仍然具有挑战性.我们制备了一种织物交错复合水凝胶(FICH)用于高效的太阳能界面蒸发.由于酸化碳纳米管均匀分布在水凝胶中并与大分子链形成氢键,水可以通过超亲水织物连续泵入复合水凝胶中,从而降低水的蒸发焓.薄型FICH蒸发器具有优异的光热转换性能,具有高蒸发速率(2.47 kg m^(2)h^(-1)),强耐盐性,长期蒸发稳定性和耐久性.此外,FICH可以用于腐蚀性溶液和乳液的净化,在太阳能海水淡化中显示出广阔的应用前景.