Interfacial Heating Research Articles

Activated carbon aerogel evaporator for simultaneous salt-rejection and inhibition of phenol from entering condensed freshwater during solar-driven seawater desalination

A novel solar-driven seawater desalination process based on air–water interfacial heating is considered as one of the effective methods for supplying freshwater on islands with shortage of electricity supply. However, salt accumulation and volatile pollutants entering into condensed freshwater are two main drawbacks that limit the application of this new process. In this work, an activated carbon (AC) aerogel with both salt-rejection property and inhibition of volatile pollutants from entering freshwater was prepared using powdered AC as a photothermal and adsorbent material and polyvinyl alcohol as a skeleton. The water evaporation rate of the AC aerogel with its external exposure heights of 0, 5, 10, 15, 20 and 25 mm were 1.25, 1.46, 1.63, 1.64, 1.68 and 1.54 kg·m−2·h−1 under 1 kW·m−2 irradiance, respectively, which are 4.13, 4.82, 5.38, 5.42, 5.55 and 5.09 times higher than that without AC aerogel. The salt-rejection property was achieved by rapid exchange of the concentrated brine with the beneath feed water though the AC aerogel. Meanwhile, the distillation rate of volatile pollutant phenol was reduced from 84.84 % to 0 % through AC adsorption, thereby purifying the condensed freshwater. Finally, an out-door seawater desalination experiment was conducted by packing 25 AC aerogels using real seawater as feed water, and the freshwater quality fitted with the standards for drinking water quality in WHO, US EPA and China.

Superhydrophobic pancake-like graphene oxide for zero liquid discharge solar desalination of real brines

Solar interfacial desalination offers a promising solution to meet the demand for portable water, especially in arid regions. Although various materials have demonstrated high solar-to-steam conversion efficiencies in concentrated solutions, most studies have utilized simulated solutions rather than real seawater. Herein, we developed a pancake-like graphene oxide photothermal membrane with superhydrophobic properties optimized for interfacial heating to desalinate real seawater and brine. Under 1 sun, the membrane efficiently achieves a sustained high evaporation rate of 1.23 kg.m−2.h−1 with a photothermal conversion efficiency of 80 %, while remarkably facilitating salt harvesting. Notably, the membrane maintained stable performance and exhibited no salt accumulation on its surface when tested outdoors with real seawater, demonstrating its practical scalability. The membrane exhibited long-term stability in desalination processes, with full performance restoration through an energy-free cleaning method. These results highlight a potential pathway toward zero-liquid discharge desalination.

Localized heating coupling with radical oxidation eliminating antibiotic resistance genes (ARGs) in interfacial photothermal Fenton-like disinfection process

Conventional oxidative disinfection processes are inefficient in eliminating intracellular antibiotic resistance genes (iARGs) due to the barrier of the cell membrane and the competitive reaction of cellular constituents within antibiotic-resistant bacteria (ARB), resulting in the widespread prevalence of ARGs in recycled water. This study presented the first application of localized heating coupling with advanced oxidation to destroy the resistant Escherichia coli cells and improved subsequent iARGs (blaTEM-1) degradation in a novel photothermal Fenton-like disinfection process. The Fe-Mn@CNT microfiltration membrane, comprising carbon nanotubes wrapped with Fe and Mn nanoparticles (Fe-Mn@CNT), was employed as a nanomaterial for photothermal conversion and H2O2 activation. The highly efficient absorption of full-spectrum photons by CNTs enabled the Fe-Mn@CNT membrane to concentrate light to generate localized intense heat, resulting in the destruction of ARB nearby, and the subsequent release of iARGs. Interfacial heat favored Fe-Mn-induced H2O2 activation, leading to the production of more ·OH, which in turn promoted the oxidation for ARG degradation and ARB cell damage. The results of the acetylcysteine quenching experiments indicated that interfacial heating and radical oxidation-induced accumulation of intracellular reactive oxygen species contributed to the elimination of about 1-log iARGs through direct attack. The integrity of the cell membrane, the morphology of ARB and the variation of i/e ARG copy numbers were observed to reveal that the introduction of interfacial heating aggravated the cell lysis and accelerated the iARGs release, resulting in the inactivation of 7.27-log ARB and the elimination of 4.64-log iARGs and 2.23-log eARGs. Localized heating coupling with ·OH oxidation achieved a 143 % increase in iARGs removal compared to the conventional Fenton-like oxidation. The interfacial photothermal Fenton-like disinfection process exhibited remarkable material stability, robust disinfection performance, and effective suppression of horizontal gene transfer, underscoring its immense potential to mitigate the risk of ARG dissemination in reclaimed water systems.

Ultrasonic micro-injection moulding: characterisation of interfacial friction by varying feedstock shape and high-speed thermal imaging for microneedle feature replication

This study explores the interfacial friction in ultrasonic micro-injection moulding by using different polymer feedstock shapes, characterisation of micromoulding melts through thermal imaging and assessing microneedle feature replication. Industry standard polypropylene pellets and discs with different thicknesses were used for varying the amount of interfacial friction during sonication. High-speed thermal imaging and tooling containing sapphire windows were used to visualise the melt characteristics. Moulded products were characterised using laser-scanning confocal microscopy to quantify microneedle replication. The study demonstrates that (i) the interfacial area for the different feedstock shapes affects the heating in ultrasonic micro-injection moulding significantly, (ii) disc-shaped feedstocks result in initially higher flow front velocities and exhibit dominance of viscoelastic heating over interfacial friction and (iii) industrial pellet feedstocks provide a good combination interfacial friction and viscoelastic heating and more viscosity reduction in overall leading to better microreplication efficiency. The results presented could have a significant impact on the process development of ultrasonic micro-injection moulding where process repeatability can be improved by controlling the interfacial friction. The research provides an essential contribution to the development of this process, where interfacial frictional heating can be tailored specifically for miniature functional components, offering improved precision and reduced energy use when compared with conventional methods.

Effect of tubular-typed charcoal height variations on efficiency in passive interfacial solar desalination

Passive solar desalination is a process of reducing the salt content of salt water to produce fresh water by utilizing solar heat. In recent years, interfacial heating has been proposed as an alternative to evaporation by creating localized heat on the water surface. Charcoal is an absorbent, heat storage, and wettability material, so the evaporation process not only occurs on the surface of seawater but also on the surface of the charcoal, which results from this wettability. The height of the charcoal indicates the distance the steam travels to reach the glass surface for the condensation process, thereby speeding up evaporation. The experiment was carried out in 4 single-slope-type basins using tubes filled with charcoal as high as 30, 40, and 50 mm for 8 hours in the sun. The results showed that adding heat-absorbing material to the basin was able to accelerate seawater to reach its boiling point so that it could evaporate. The temperature and humidity in each basin also have a similar changing trend where temperature is strongly influenced by solar radiation. The use of charcoal can also increase the rate of convection and evaporation heat transfer in the basin, as well as the maximum efficiency in basin 4 with an efficiency value of 56.40%, basin 2 at 53.17%, basin 3 at 51.62%, and basin 1 44.17%. Efficiency is obtained from the desalination efficiency equation, namely the ratio of the latent heat of vaporization to the solar energy entering the system

Experimental investigation on the transient vascular thermal response to laser irradiation by a high-speed infrared thermal camera

Based on the photothermal effect, laser can be used to treat vascular diseases (VD) in clinic of dermatology and ophthalmology. Transient vascular thermal response to laser irradiation during millisecond laser pulse is the key phenomenon in treatment process, which has not been carefully investigated before. In this study, target blood vessels in dorsal skin chamber (DSC) animal model were irradiated by a pulsed 532 nm diode laser and a 1064 nm Nd:YAG laser. The directed thermal responses (temperature variation) were recorded by a high-speed infrared thermal camera with a repetition rate of 1000 Hz. The temperature variation during and after single pulse irradiation and multipulse irradiation were investigated. The variation of blood absorption coefficient was explored based on the temperature increment in each laser pulse. The thermal properties of dorsal skin, especially the thermal diffusivity, were evaluated based on the temperature decay after each laser pulse. The interfacial heat transfer between the blood and the surroundings was also calculated based on the thermal images and compared to the correlation proposed before. The results show that the blood absorption to laser will increase by a maximum of 1.9 immediately after blood temperature exceeds threshold value, e.g., 68oC in both single pulse (pulse duration >100 ms) and multi-pulse laser irradiation. The tissue optical properties (thermal diffusivity) keep almost constant after millisecond laser heating. Also, a general correlation for interfacial heating transfer between blood and surroundings was developed, in which the influences of vessel shape and laser wavelength are incorporated. The interfacial heat transfer between blood and surrounding can be accurately quantified.

Twisted integration of high-efficiency photothermal/water-transported yarns for boosting solar-powered fabric evaporator

Positioned as high-efficiency low-cost desalination technology, solar interfacial vapor generation still remains challenging in precisely managing interfacial photothermal behaviors. Here, an integral solar-heating yarn twisted by both carbon nanotube (CNT) fibers and cotton yarns processed via carbon black slurry is developed for architecting high-efficiency fabric evaporators, where modified CNT and cotton serve as the solar-heating unit and water-supply unit, respectively. The unique structure of hybrid yarns features pronounced gradient photothermal difference of 5 °C between CNT and cotton regions in dry state, and meanwhile enables robust Marangoni vapor flows and weak hydration state. As a result, the crafted fabric evaporator has a superior evaporation rate of 2.83 kg m−2 h−1, which is the highest value reported among 2D fabric evaporators. This work introduces an innovative strategy for high-efficiency interfacial solar heating, significantly boosting evaporation performance of flexible and portable evaporators.

Bioinspired magnetically generated bilayer aerogel with vertically aligned pores: Efficient solar evaporation and water purification for crop production

Facing the challenge of freshwater scarcity, solar evaporation technology with interfacial heating is considered to be a technology that uses solar energy to sustainably obtain fresh water through evaporation and condensation processes. However, the construction of a solar-driven evaporation system capable of consistently, efficiently, and steadily producing pure water under sunlight is pivotal yet challenging. In this work, inspired by mushrooms, a magnetic-generated double‑layered solar evaporator is designed for efficient water evaporation. With the thermal management of the aerogel and the vertical arrangement of the water channels, this evaporator overcomes the trade-off between water delivery and heat management that has long plagued traditional evaporators. In addition, the presence of cold evaporation breaks the long-existing photothermal efficiency of traditional solar evaporation cannot exceed the limit of 100 %. With this structure, an evaporation rate of 1.966 kg m−2 h−1 and a solar-to-vapor energy efficiency of 120.6 % are achieved under irradiation of 1 sun. The mung beans are irrigated with pure water obtained by evaporation to germination. The work provides a new direction for manufacturing evaporators and key insights into addressing water scarcity and the use of water.

Generation of H2O2 and halogenated by-products at the evaporator surface during seawater desalination based on air-water interfacial solar heating

Seawater desalination based on air-water interfacial solar heating has attracted significant attention in recent years. However, the “high temperature, high salinity, sunlight irradiation and enrichment of photosensitive substances” environment formed at the evaporator surface unavoidably enhances the photochemical reaction, which in the next step may lead to the production of active species and by-products. In this work, H2O2, as an important reactive oxygen species and a transit substance for reactive oxygen species such as ·OH, 1O2, and ·O2−, was monitored during solar evaporation. The average H2O2 concentration at the evaporator surface was 2.24 mg·L−1 with a maximum concentration of 5.0 mg·L−1, which is significantly higher than the average H2O2 concentration in the ocean. The effects of the nitrate ions, halogen ions, iron ions, dissolved organic matter, and solar intensity on the generation of H2O2 concentrations were explored. Finally, halogenated by-products were detected at the evaporator surface when phenol, a model pollutant, was present in the feedwater. This work fills the knowledge gap in understanding the generation of H2O2 and the formation of halogenated by-products at the evaporator surface during solar evaporation.

An efficient photothermal conversion material based on D‐A type luminophore for solar‐driven desalination

AbstractSolar‐driven interfacial evaporation is a promising technology for desalination. The photothermal conversion materials are at the core and play a key role in this field. Design of photothermal conversion materials based on organic dyes for desalination is still a challenge due to lack of efficient guiding strategy. Herein, a new D (donor)‐A (acceptor) type conjugated tetraphenylpyrazine (TPP) luminophore (namely TPP‐2IND) was prepared as a photothermal conversion molecule. It exhibited a broad absorption spectrum and strong π–π stacking in the solid state, resulting in efficient sunlight harvesting and boosting nonradiative decay. TPP‐2IND powder exhibited high photothermal efficiency upon 660 nm laser irradiation (0.9 W cm−2), and the surface temperature can reach to 200°C. Then, an interfacial heating system based on TPP‐2IND is established successfully. The water evaporation rate and the solar‐driven water evaporation efficiency were evaluated up to 1.04 kg m−2 h−1 and 65.8% under 1 sunlight, respectively. Thus, this novel solar‐driven heating system shows high potential for desalination and stimulates the development of advanced photothermal conversion materials.

Au-loaded ZIF-8 derived porous carbon with improved photothermal catalysis ability from interfacial heating instead of hot-electrons

Photothermal catalysis has attracted increasing attention due to the efficient utilization of sustainable solar energy and high catalytic activity. However, its practical application is still limited due to the complex synthesis and low surface area of photothermal materials, as well as the challenges of distinguishing the effects of hot electrons and localized heating. To solve these issues, ZIF-8 derived porous carbon (ZPC) nanocrystals were constructed as high surface area photothermal materials and then decorated with Au nanoparticles as the catalytic components. Au/ZPC nanocomposites are prepared by the assembly of ZIF-8, the pyrolysis and in-situ Au reduction process. They are composed of rhombic dodecahedron-shaped ZPC with an average diameter of ∼120 nm, where Au nanoparticles (2–8 nm) are dispersed well on the surface or within the pore structure of ZPC. Besides, Au/ZPC exhibits a wide range of light absorption between 200 and 1100 nm and high photothermal efficiency of 45 %. With 4-nitrophenol (4-NP) reduction reaction as a model system, Au/ZPC catalyst exhibits a 2-fold increase in the rate of 4-NP reduction when exposed to an 808 nm laser irradiation, in comparison to thermocatalysis at the same temperature. Furthermore, the activation energy for the reduction of 4-NP via photothermal catalysis was much lower than that of thermocatalysis (74.16 vs. 104.26 kJ mol−1). By excluding hot electrons effects by transient absorption (TA) spectra, we can establish that the increase of photothermal catalysis rate should result from the localized heating which can decrease the energy barriers for the reduction of 4-NP. Additionally, Au/ZPC displays high stability and maintains remarkable activity even after five cycles. This study may provide some new perspectives for the design and development of efficient photothermal catalysts.

Solar-driven surface-heating membrane distillation using Ti3C2Tx MXene-coated spacers

The emergence of two-dimensional (2D) MXenes as efficient light-to-heat conversion materials offers significant potential for solar-based desalination, particularly in photothermal interfacial evaporation, enabling cost-effective solar-powered membrane distillation (MD). This study investigates solar-powered MD afforded by a photothermally functionalized spacer, which is built by spray-coating Ti3C2Tx MXene sheets on metallic spacers. 2D Ti3C2Tx MXene gives an ultrahigh photothermal conversion efficiency; thereby, by Ti3C2Tx MXene-coated metallic spacer, this rationally designed spacer allows for a localized photothermal conversion and interfacial feed heating effect on the membrane surface, especially for MD operation. As a feed spacer and a photothermal element, Ti3C2Tx MXene-coated metallic spacer exhibited stable enhanced water flux of up to 0.36 kg·m−2h−1 under one sun illumination for a feed salinity of 35 g·L−1, corresponding energy conversion efficiency of 28.3 %. Overall, the developed photothermal Ti3C2Tx MXene-coated spacers displayed great potential in enhancing the performance, scalability, and feasibility of solar-driven MD process, paving the way for further development of photothermal elements that can be implemented in solar MD applications.

Scalable Carbon Black‐Enabled Membranes for Sustainable Solar Membrane Desalination

AbstractSolar energy is used worldwide for generating electricity or desalting seawater. Photothermal membrane distillation (PMD), an emerging thermal‐driven process for seawater desalination, combines interfacial heating with membrane distillation (MD) technology to address the energy consumption issues of conventional MD. However, it is still a great challenge to develop a cost‐effective and scalable membrane, which hampers the practical use of PMD. Herein, a dual‐layer carbon black (CB)/PVDF membrane is prepared via direct electrospraying on a commercial PVDF membrane. With the introduction of a functional layer, a photothermal effect is imparted to the bare membrane, thus significantly increasing the water production rate and solar utilization efficiency (SUE) during exposure to artificial sunlight (≈57% enhancement and 72% SUE under 1 sun). In addition to the outstanding photothermal properties, this functional layer also served as a passivation coating to synergistically reduce the crystallization rate and physical binding of inorganic salts on the modified membrane without adding hazardous chemicals or using laborious steps. This multifunctional coated membrane and fast‐growing solar desalination technology provides a promising solution to the water crisis, especially in off‐grid areas where energy and resources are both relatively insufficient.

Solventless autothermic production of energy-intensive furanic biofuels expedited by photothermal effect

Driving C-C coupling reactions to produce biofuels is usually energy-consuming and requires well-tailored catalysts. Herein, a novel photothermal catalytic strategy was developed to be highly efficient for cascade hydroxyalkylation-alkylation (HAA) of various biomass-derived aldehydes/ketones with 2-methylfuran or acetalization of different bioalcohols with furfural to exclusively afford furanic biofuel molecules (up to 94.8 % yield). The developed bio-based SO3H-functionalized graphene-like catalyst (GLB-SO3H-700) could complete the HAA and acetalization reactions in 10 min under solvent-free and room-temperature conditions. Infrared thermal imaging revealed that the local photothermal effect of interfacial solar heating could in-situ remove water co-product, thereby improving the reaction selectivity and rate as evidenced by kinetic study. Moreover, the GLB-SO3H-700 catalyst exhibited good stability and recyclability. The developed SO3H-functionalized graphene-like photothermal materials hold great potential for catalytic upgrading of biomass into high-quality biofuels under mild conditions.

An improved micromechanical model for the thermal conductivity of multi-scale fiber reinforced ultra-high performance concrete under high temperatures

An improved micromechanical model to estimate the thermal conductivity of multi-scale fiber reinforced ultra-high performance concrete (MSFUHPC) subjected to elevated temperatures is formulated in this study. This model considers the contributions of microstructure, multiscale fibers, water/cement ratio, thermal dehydration of hydrates, thermal cracking, interfacial thermal resistance, heating rate and temperature dependent thermal conductivity of each phase. To verify the proposed model, comparisons with experimental data on MSFUHPC specimens are carried out. Accordingly, factors affecting the thermal conductivity of MSFUHPC are discussed through the proposed model. Results suggest that blending multi-scale fibers and increasing the sand content can significantly enhance the thermal conductivity of MSFUHPC. While adding cenosphere particles can reduce the thermal conductivity. Overall, the thermal conductivity of MSFUHPC exhibits a decreasing trend with temperature. Meanwhile, thermal cracking occurs beyond 400 °C can remarkably decrease the thermal conductivity of MSFUHPC. A higher interfacial thermal resistance between sands and the matrix can result in a lower thermal conductivity. It is also found that thermal conductivity mainly depends on the maximum temperature experienced rather than the heating rate.

High Freshwater Flux Solar Desalination via a 3D Plasmonic Evaporator with an Efficient Heat-Mass Evaporation Interface.

Passive solar desalination with interfacial heating is a promising technique to utilize solar energy to convert seawater into fresh water through evaporation and condensation. However, the current freshwater flux of solar desalination is much below industrial requirements (> 20 Lm-2 h-1 ). Herein, it is demonstrated that a 3D plasmonic evaporator with an efficient heat-mass evaporation interface (HM-EI) achieves a freshwater flux of 29.1 Lm-2 h-1 for 3.5 wt.% NaCl, which surpasses the previous solar evaporators and approaches the level of reverse osmosis (the highest installed capacity in industrial seawater desalination technology). The realization of high freshwater flux solar desalination comes from the efficient HM-EI comprising a grid-like plasmonic macrostructure for enhanced energy utilization in heat properties and a large-pore microstructure for accelerated ion transport in mass properties. This work provides a new direction for designing next-generation solar evaporators with high freshwater flux for industrial requirements.

Customized Microenvironments Spontaneously Facilitate Coupled Engineering of Real-Life Large-Scale Clean Water Capture and Pollution Remediation.

Harnessing abundant renewable resources and pollutants on a large scale to address environmental challenges, while providing sustainable freshwater, is a significant endeavour. This study presents the design of fully functional solar vaporization devices (SVD) based on organic-inorganic hybrid nanocomposites (CCMs-x). These devices exhibit efficient photothermal properties that facilitate multitargeted interfacial reactions, enabling simultaneous catalysis of sewage and desalination. The localized interfacial heating generated by the photothermal effect of CCMs-x triggers surface-dominated catalysis and steam generation. The CCMs-x SVD achieves a solar water-vapor generation rate of 1.41kg m-2 h-1 (90.8%), and it achieves over 95% removal of pollutants within 60min under one-sun for practical application. The exceptional photothermal conversion rate of wastewater for environmental remediation and water capture is attributed to customized microenvironments within the system. The integrated parallel reaction system in SVD ensures it is a real-life application in multiple scenarios such as municipal/medical wastewater and brine containing high concentrations. Additionally, the SVD exhibits long-term durability, antifouling functionality toward complex ionic contaminants. This study not only demonstrates a one-stone-two-birds strategy for large-scale direct production of potable water from polluted seawater, but also opens up exciting possibilities for parallel production of energy and water resources.

Fatigue life and failure mechanism of nylon 66 cord/rubber composites under wide temperature range

This work simulates the real harsh service conditions of Fiber-reinforced polymer composites (FRPC), and the dynamic adhesion and failure mechanism of nylon 66 (PA66)-reinforced natural rubber (NR) composites under large deformation and wide temperature range are deeply studied by comprehensive analysis of the interfacial adhesion evolution, microstructure and failure damage location of the composites, interfacial heating rate, and modulus ratio of PA66/NR. The failure mechanism of PA66/NR composites is interfacial debonding at −20 °C, 25 °C and 80 °C, whereas that at 120 °C is matrix cracks. Interestingly, at −20 °C, the crack expansion at the interface is slow, and the samples show two-stage damage during fatigue, resulting in the highest fatigue life. At 80 °C, the interface heating rate and modulus ratio of the PA66/NR composites is the lowest, and thus the fatigue life is higher than that at 25 °C and 120 °C. Keywords: fiber reinforced polymer composites, fatigue life, failure mechanism.

Multi-Functional Janus Hollow Solar Evaporator Based on Copper Foam for Non-Contact High-Efficiency Solar Interfacial Distillation.

As a sustainable, clean, and friendly technology with a minimal carbon footprint when treating seawater or wastewater, interfacial solar vapor generation (ISVG) technology is a great alternative to traditional desalination and water purification methods (e.g., reverse osmosis and ultrafiltration). So far, it presents tremendous potential for applications in realizing desalination of seawater or brine, wastewater treatment, and so forth. However, the precipitated salt particles during conventional ISVG inevitably block the evaporator surface, resulting in the degradation of photothermal conversion and decrease of evaporation rate. Herein, a multi-functional non-contact Janus hollow evaporator based on copper foam was prepared, which was assembled by a hydrophobic light-to-heat conversion layer and a hydrophilic interfacial water evaporation layer as two separate parts. Accordingly, the precipitated salt in the ISVG system does not block the photothermal interface, increasing the stability of solar capture and reusability of the evaporator. Notably, the hollow structure of the evaporator has a local interfacial heating effect, endowing the evaporation system with a high seawater evaporation rate of 2.249 kg m-2 h-1. The evaporator is capable of stable operation for 10 h under 1 sun illumination even when evaporating concentrated brine (15 wt %). Moreover, the evaporation rate of water under one sun irradiation reached 2.284 kg m-2 h-1 and the solar-to-vapor efficiency reached 96.6%. Not only that, the evaporator was able to successfully purify wastewater containing dyes and heavy metal ions. The multi-functional Janus hollow interfacial solar evaporator will provide inspiration for upcoming research on the production of safety water.

The construction of composite hydrogel evaporator with interfacial heating performance and its application in water treatment

To meet the needs of sewage cleaning and clean drinking water, a multifunctional photothermal device is designed in this paper, which mainly includes the non-infiltrating layer of copper stearate, bismuth tungstate and copper oxide composite hydrogel. By improving the synthesis process, sheet-like copper stearate and flower-like bismuth tungstate were prepared, realizing the load of canvas, felt and fabric, with the contact angles reaching 158º, 162º and 161º, respectively. The nonwetting layer has the performance of not only selective oil removal, but also mechanical stability. Through traditional non-infiltrating materials, dyes cannot be degraded, while with the introduction of bismuth tungstate, superhydrophobic materials are given photodegradation properties, thus solving the recovery problem of powder photocatalysts. The photodegradation stability was demonstrated via multiple photodegradation processes by calculating the reaction kinetic coefficient, with a degradation efficiency of greater than 90%. The position of valence (1.9 eV) and conduction (-0.735 eV) band of bismuth tungstate was calculated based on Mott-Schottky curve, DRS and VB-XPS. With the construction of copper oxide composite hydrogel, the mechanical stability was improved and an efficiency of 1.76 kg•m−2•h−1 was obtained. The composite hydrogel device can also be used to treat the aqueous solutions containing metal ions and dyes, which operates stably in aqueous solutions containing 3.5% NaCl without salt crystallization, thus proving the application value of the photothermal device.