Introducing solar energy into membrane filtration to decrease energy and chemicals consumption represents a promising direction in membrane fields. In this study, a kind of 0D/2D heterojunction is ...fabricated by depositing biomineralized titanium dioxide (TiO2) nanoparticles with delaminated graphitic carbon nitride (g‐C3N4) nanosheets, and subsequently a kind of 2D heterostructure membrane is fabricated via intercalating g‐C3N4@TiO2 heterojunctions into adjacent graphene oxide (GO) nanosheets by a vacuum‐assisted self‐assembly process. Due to the enlarged interlayer spacing of GO nanosheets, the initial permeation flux of GO/g‐C3N4@TiO2 membrane reaches to 4536 Lm−2 h−1 bar−1, which is more than 40‐fold of GO membranes (101 Lm−2 h−1 bar−1) when utilized for oil/water separation. To solve the sharp permeation flux decline, arising from the adsorption of oil droplets, the a sunlight‐driven self‐cleaning process is followed, maintaining a flux recovery ratio of more than 95% after ten cycles of filtration experiment. The high permeation flux and excellent sunlight‐driven flux recovery of these heterostructure membranes manifest their attractive potential application in water purification.
A 2D heterostructure membrane is fabricated via intercalating a g‐C3N4@TiO2 heterojunction into adjacent graphene oxide (GO) nanosheets by a vacuum‐assisted self‐assembly process. The enlarged interlayer spacing of GO nanosheets endows the 2D heterostructure membrane a with high permeation flux, and the photocatalytic activity of g‐C3N4@TiO2 0D/2D heterojunctions endows the 2D heterostructure membrane with self‐cleaning ability for the separation of oil‐in‐water emulsions.
The in-situ leaching of rare earth minerals results in ecological differences between sunlit and shady slopes, which may be related to differences in the distribution REEs in the associated soil ...matrices. Studies of REEs mine tailings in Southern China indicated higher total concentrations of REEs on sunlit slopes compared to shady ones. Specifically, the exchangeable REEs fraction (F1-REEs) was higher on the shady slopes, whereas the Fe/Mn oxides bound REEs fraction (F3-REEs) was higher on the sunlit slopes. In addition, light REE (LREE) concentrations were lower at lower elevations. With the exception of the Ce fraction which remained stable, this indicated a change in all REEs distributions, moving from F1-REEs towards the residual fraction. Hierarchical cluster and principal component analysis revealed a strong correlation between F3-REEs, organic matter bound REEs (F4-REEs), and LREEs, and a positive association of F3-REEs with sunlight exposure. Partial Least Squares Path Modeling analysis suggested that OM promoted the conversion of LREEs to F3 and F4-REEs in soil driven by sunlight exposure. Additionally, as the Feo/Fed ratio decreased, more LREEs were converted to F3. This study suggests that sunlight and elevation both play a critical role in the geochemical dynamics of REEs in in-situ tailings, advocating for environmental evaluations to be undertaken in order to accurately understand the ecological impacts of rare earth mining.
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•REEs distributed differently on sunlit and shady slopes after in-situ leaching.•The exchangeable REEs was higher on the shady slopes.•Sunlit slopes had higher Fe/Mn oxides bound REEs.•Light REEs and exchangeable REEs decreased with decreasing elevation.•Fe oxides and OM dominated the the mobility of REEs in mine tailings soil.
Nanoscale oxide layer protected semiconductor photoelectrodes show enhanced stability and performance for solar fuels generation, although the mechanism for the performance enhancement remains ...unclear due to a lack of understanding of the microscopic interfacial field and its effects. Here, we directly probe the interfacial fields at p-GaP electrodes protected by n-TiO
and its effect on charge carriers by transient reflectance spectroscopy. Increasing the TiO
layer thickness from 0 to 35 nm increases the field in the GaP depletion region, enhancing the rate and efficiency of interfacial electron transfer from the GaP to TiO
on the ps time scale as well as retarding interfacial recombination on the microsecond time scale. This study demonstrates a general method for providing a microscopic view of the photogenerated charge carrier's pathway and loss mechanisms from the bulk of the electrode to the long-lived separated charge at the interface that ultimately drives the photoelectrochemical reactions.
Inorganic metal halide perovskites, such as CsPbI
, have recently drawn extensive attention due to their excellent optical properties and high photoelectric efficiencies. However, the structural ...instability originating from inherent ionic defects leads to a sharp drop in the photoelectric efficiency, which significantly limits their applications in solar cells. The instability induced by ionic defects remains unresolved due to its complicated reaction process. Herein, to explore the effects of ionic defects on stability, we develop a deep learning potential for a CsPbI
ternary system based upon density functional theory (DFT) calculated data for large-scale molecular dynamics (MD) simulations. By exploring 2.4 million configurations, of which 7,730 structures are used for the training set, the deep learning potential shows an accuracy approaching DFT-level. Furthermore, MD simulations with a 5,000-atom system and a one nanosecond timeframe are performed to explore the effects of bulk and surface defects on the stability of CsPbI
. This deep learning potential based MD simulation provides solid evidence together with the derived radial distribution functions, simulated diffraction of X-rays, instability temperature, molecular trajectory, and coordination number for revealing the instability mechanism of CsPbI
. Among bulk defects, Cs defects have the most significant influence on the stability of CsPbI
with a defect tolerance concentration of 0.32 %, followed by Pb and I defects. With regards to surface defects, Cs defects have the largest impact on the stability of CsPbI
when the defect concentration is less than 15 %, whereas Pb defects act play a dominant role for defect concentrations exceeding 20 %. Most importantly, this machine-learning-based MD simulation strategy provides a new avenue to explore the ionic defect effects on the stability of perovskite-like materials, laying a theoretical foundation for the design of stable perovskite materials.
In this study, six different types of residential areas in Guiyang were selected as the research objects, including high-rise high-density, high-rise low-density, middle-rise high-density, ...middle-rise low-density, low-rise high-density and low-rise low-density. The indices of sunshine compliance rate and the building's sunshine hour ratio were constructed to compare and analyze sunshine environment across those six different residential areas. The factors influencing sunshine environment in different residential areas were studied. The results showed that the average sunshine compliance rates of the six types of residential areas were 36.9%, 61.9%, 20.6%, 69.6%, 26.5% and 45.0%, respectively. The average sunshine compliance rate of low-density residential areas was 2.25 times higher than that of high-density residential areas within the same type, among which the sunshine environment of low-density residential areas was better. The sunshine environment of different types of low-density residential areas was d
Owing to the significant role of sunlight hours in human survival, it is crucial to assess the fairness of sunlight resource allocation among different socioeconomic classes, which is essential for ...the overall harmonious development of a society. This study focused on selected residential communities in Fuzhou, China, and conducted a simulation analysis of sunlight hours using a Solar Grid Model. Additionally, based on the transaction prices of residential properties in the area, this study employs regression analysis to discuss the current supply and demand of sunlight hours for residences with different price ranges. This study found that properties belonging to the lower-spending group may experience excessive sunlight hours during summer. An increase of one hour in sunlight hours on the summer solstice is associated with a decrease of approximately 45,000 RMB in the total property price. In contrast, the higher-spending group is more likely to face insufficient sunlight during winter, and an increase of one hour in sunlight hours on the winter solstice is associated with an approximate 28,000 RMB rise in the total property price. Furthermore, the study found that controlling the size of the property area for medium- to low-priced residential properties within a range of 113 m2 enables better utilization of sunlight resources. In contrast, high-priced residences, if designed with large protrusions, are prone to wasting sunlight resources. This study employed a novel approach to simulate and replicate the current sunlight conditions in urban architectural clusters. For the first time, this study systematically analyzed variations in the demand for sunlight hours across different socioeconomic groups, using property prices as references. Finally, this study summarizes the typical characteristics of sunlight design issues related to residential sample variations and proposes corresponding solutions.
Contaminants of emerging concern (including pharmaceuticals) are not effectively removed by municipal wastewater treatment plants (WWTPs), so particular concern is related to agricultural wastewater ...reuse due to their possible uptake in crops irrigated with WWTPs effluents. Advanced oxidation processes (AOPs) and solar AOPs have been demonstrated to effectively remove pharmaceuticals from different aqueous matrices. In this study, an heterogeneous photocatalytic process using powdered nitrogen-doped TiO2 immobilized on polystyrene spheres (sunlight/N–TiO2) was compared to the benchmark homogenous AOP sunlight/H2O2 in a compound triangular collector reactor, to evaluate the degradation of three pharmaceuticals (carbamazepine (CBZ), diclofenac (DCF), trimethoprim (TMP)) in water. The degradation of the contaminants by sunlight and sunlight-AOPs well fit the pseudo-first order kinetic model (but for TMP under sunlight). High removal efficiency by solar photolysis was observed for DCF (up to 100%, half-life sunlight cumulative energy QS,1/2 = 2 kJ L−1, half-life time t1/2 = 32 min), while CBZ (32%, QS,1/2 = 28 kJ L−1, t1/2 = 385 min) and TMP (5% removal after 300 min) removal was poor. The degradation rate of CBZ, TMP and DCF was found to be slower during sunlight/H2O2 (QS,1/2 = 5 kJ L−1, t1/2 = 77 min; QS,1/2 = 20 kJ L−1, t1/2 = 128 min; QS,1/2 = 4 kJ L−1, t1/2 = 27 min, respectively) compared to sunlight/N–TiO2 (QS,1/2 = 4 kJ L−1, t1/2 = 55 min; QS,1/2 = 3 kJ L−1, t1/2 = 42 min; QS,1/2 = 2 kJ L−1, t1/2 = 25 min, respectively). These results are promising in terms of solar technology upscale because the faster degradation kinetics observed for sunlight/N–TiO2 process would result in smaller treatment volume, thus possibly perspective compensating the cost of the photocatalyst.
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•Comparison between homogeneous and heterogeneous solar driven AOPs.•The degradation of the contaminants well fit pseudo-first order kinetic model.•Diclofenac effectively degraded even by solar photolysis.•Faster degradation of pharmaceuticals by sunlight/N–TiO2 compared to sunlight/H2O2.•Sunlight/N–TiO2 process would result in a smaller treatment volume than sunlight/H2O2.
