Osmotic energy between river water and seawater has attracted interest as a new source of sustainable energy. Nanofluidic membranes in a reverse electrodialysis configuration can capture energy from ...salinity gradients. However, current membrane materials suffer from high resistances, low stabilities, and low charge densities, which limit their further application. Here, we designed a high-performance nanofluidic membrane using carboxylic cellulose nanofibers functionalized with graphene oxide nanolamellas with cement-and-pebble microstructures and stable skeletons for enhanced ion transmembrane transport. By mixing artificial river water and seawater, the composite membrane achieved a high output power density up to 5.26 W m
−2
. Additionally, the membrane had an excellent acid resistance, which enabled long-term use with over 67 W m
−2
of power density. The performance of this composite membrane benefited from the mechanically strong cellulose fibers and the bonding between nanofibers and nanolamellas. In this work, we highlight promising directions in industrial waste treatment using energy extracted from chemical potential gradients.
Highlights
The first construct of a multi-field-coupled synergistic ion transport system (MSITS) in Li
+
extraction is proposed.
Effectively suppress the ion concentration polarization effect of the ...ion-enrichment zone at the membrane interface.
The MSITS equipped with heterogeneous membrane exhibited outstanding separation performance with Li
+
flux of 367.4 mmol m
−2
h
−1
and Li
+
/Co
2+
selectivity of 216,412, outperforming previous reports.
The global carbon neutrality strategy brings a wave of rechargeable lithium‐ion batteries technique development and induces an ever-growing consumption and demand for lithium (Li). Among all the Li exploitation, extracting Li from spent LIBs would be a strategic and perspective approach, especially with the low energy consumption and eco-friendly membrane separation method. However, current membrane separation systems mainly focus on monotonous membrane design and structure optimization, and rarely further consider the coordination of inherent structure and applied external field, resulting in limited ion transport. Here, we propose a heterogeneous nanofluidic membrane as a platform for coupling multi-external fields (i.e., light-induced heat, electrical, and concentration gradient fields) to construct the multi-field-coupled synergistic ion transport system (MSITS) for Li-ion extraction from spent LIBs. The Li flux of the MSITS reaches 367.4 mmol m
−2
h
−1
, even higher than the sum flux of those applied individual fields, reflecting synergistic enhancement for ion transport of the multi-field-coupled effect. Benefiting from the adaptation of membrane structure and multi-external fields, the proposed system exhibits ultrahigh selectivity with a Li
+
/Co
2+
factor of 216,412, outperforming previous reports. MSITS based on nanofluidic membrane proves to be a promising ion transport strategy, as it could accelerate ion transmembrane transport and alleviate the ion concentration polarization effect. This work demonstrated a collaborative system equipped with an optimized membrane for high-efficient Li extraction, providing an expanded strategy to investigate the other membrane-based applications of their common similarities in core concepts.
Membrane‐based osmotic power harvesting is a strategy for sustainable power generation. 2D nanofluids with high ion conductivity and selectivity are emerging candidates for osmotic energy conversion. ...However, the ion diffusion under nanoconfinement is hindered by homogeneous 2D membranes with monotonic charge regulation and severe concentration polarization, which results in an undesirable power conversion performance. Here, an asymmetric nanochannel membrane with a two‐layered structure is reported, in which the angstrom‐scale channels of 2D transition metal carbides/nitrides (MXenes) act as a screening layer for controlling ion transport, and the nanoscale pores of the block copolymer (BCP) are the pH‐responsive arrays with an ordered nanovoid structure. The heterogeneous nanofluidic device exhibits an asymmetric charge distribution and enlarged 1D BCP porosity under acidic and alkaline conditions, respectively; this improves the gradient‐driven ion diffusion, allowing a high‐performance osmotic energy conversion with a power density of up to 6.74 W m−2 by mixing artificial river water and seawater. Experiments and theoretical simulations indicate that the tunable asymmetric heterostructure contributes to impairing the concentration polarization and enhancing the ion flux. This efficient osmotic energy generator can advance the fundamental understanding of the MXene‐based heterogeneous nanofluidic devices as a paradigm for membrane‐based energy conversion technologies.
This work demonstrates the use of asymmetric nanochannel membranes composed of metal carbides/nitride and block copolymer layers for harvesting osmotic energy. This membrane with chemical, geometrical, and electrostatic heterostructures contributes to impairing the concentration polarization. In nanoconfinement, the membrane preserves the surface‐charge‐governed ion transport and exhibits excellent ion selectivity and flow, achieving a high‐performance power density of 6.74 W m−2.
Depression is a global psychological disease that does serious harm to people. Traditional diagnostic method of the doctor-patient communication, is not objective and accurate enough. Thus, a more ...accurate and objective method for depression detection is urgently needed. Resting-state electroencephalography (EEG) can effectively reflect brain function, which have been used to study the difference of the brain between the depression patients and normal controls. In this work, the Resting-state EEG data of 27 depression patients and 28 normal controls was used in this study. We constructed the brain functional network using correlation, and extracted four linear features of EEG (activity, mobility complexity and power spectral density). We utilized a learnable weight matrix in the input layer of graph convolution neural network, creatively took the brain function network as the adjacency matrix input and the linear feature as the node feature input. We proposed our model Graph Input layer attention Convolutional Network (GICN), and it provided a good performance, showing the accuracy of 96.50% for recognition of depression and normal with 10-fold cross-validation, which indicated that our model could be used as an effective auxiliary tool for depression recognition. Besides, our method significantly outperformed other method. Additionally, the learnable weight matrix in the input layer was also used to find some edges and nodes that played an important role in depression recognition. Our findings showed that temporal lobe and parietal-occipital lobe had great effect in depression identification.
•In the step of designing the adjacency matrix of graphs, there may exists some long-distance connections in the brain. Simply defining neighbors by distance may result in the loss of important information. In response to this problem, we use functional connections instead of spatial distance connections for our research.•To obtain the weight of each functionally connected edge of the brain network in depression recognition, we used a weight matrix Wα in the graph input attention layer to dot-multiply each edge in the brain network. After training, the weight value reflects the importance of this edge in the depression classification.•The research results give a new insight into the construction of depression recognition model, and can also provide theoretical basis and technical support for the pervasive application systems.
•Soil properties of mining area had a strong spatial autocorrelation in four seasons.•The chemical and biological properties of soil decreased with the mining subsidence degree.•The activities of ...microorganism in soil were stronger in spring and weaker in winter.
Land subsidence due to underground mining results in soil nutrient loss and reduced soil fertility. Land reclamation, which refers to the improvement of soil nutrients through targeted measures, requires spatial and temporal distribution information on the soil properties. However, this has not yet been studied. Therefore, the spatial autocorrelation of soil chemical and biological properties was examined in the Pingdingshan coal mining area during four seasons in China from 80 collected and analyzed soil samples. The spatial autocorrelation was determined by the global and local Moran’s indices. Spatial clustering and variability were analyzed with ArcGIS 10.2 (Environmental Systems Research Institute, ESRI, USA) and GeoDa 7.0 software (Center for Spatial Data Science in University of Chicago, USA). Soil pH and the soil total carbon (TC) content, soil total nitrogen (TN) content, soil available phosphorus (AP) content, and soil alkali-hydrolyzable nitrogen (AN) content were measured as soil chemical properties. The soil biological properties included the quantities of bacteria, actinomycetes, and fungi. The soil chemical and biological properties showed a strong spatial autocorrelation during the four seasons. “High-high” and “low-low” were the dominant autocorrelation types that were distributed in serious and light subsidence areas. The soil properties decreased as the mining subsidence degree increased. Both the soil TC and soil AP contents were highest in spring, the soil TN content was highest in autumn, and the soil AN content was highest in summer. These results provide a reliable theoretical reference for land reclamation and ecological restoration in mining areas.
Access to uranium resources is critical to the sustainable development of nuclear energy. The ocean contains abundant uranium resources, but the marine biological pollution and the low concentration ...of uranium make it a giant challenge to extract uranium from seawater. On the foundation of selective uranium adsorption using high uranium‐affinity groups, realizing the external‐field improved uranium capture without extra energy consumption is highly attractive. A solar thermal collector with 3D ion‐transport networks based on environmentally friendly biomass adsorption material is reported, which contains antibacterial adsorption ligands and photothermal graphene oxide. The antibacterial ability through an easy one‐step reaction and the fast mass transfer caused by photothermal conversion collaboratively improve the original adsorption capacity of the hydrogel by 46.7%, reaching 9.18 mg g−1 after contact with natural seawater for 14 days. This study provides a universal strategy for the design of physical‐fields‐enhanced hydrogel adsorbents.
A phosphate‐group‐based solar biomass thermal collector with antibacterial ability is designed to extract uranium from seawater effectively. The photothermal conversion of GO and the antibacterial ability of quaternary ammonium functional groups promote the coordination of uranium with binding sites and accelerate ion transport while uranium capture, which can significantly increase the adsorption performance of hydrogel‐based sorbents.
Large quantities of marine ballast water discharged by ocean-going vessels can cause salinity increases in freshwater ports, which in turn negatively affects indigenous plankton in the ports. In this ...study, we investigated the impacts of marine ballast water discharge on the plankton community in a freshwater wharf through field surveys. It was found that salinity stress caused reductions in community indicators such as plankton community composition, abundance and diversity, thus threatening the structure and function of the plankton community in the wharf. In terms of the impact range, the salinity stress had a significant effect on all plankton in the waters near the discharge point and the phytoplankton in the waters 50 m from the discharge point, but had no significant effect on the plankton in the waters further away. Ballast water discharge also caused a significant decrease in the alpha diversity and richness of the plankton community but had no significant effect on the evenness of the plankton community. Moreover, phytoplankton were more tolerant of salinity changes than zooplankton in our study. This study provides an ecological reference for the scientific management of marine ballast water discharge and the risk of exogenous nutrient inputs to freshwater ecosystems.
•Discharges of marine ballast water can be detrimental to indigenous plankton in freshwater ports.•Phytoplankton are more tolerant to salinity changes than zooplankton in this study.•The ballast water discharge led to significant decreases in the α-diversity and abundance of freshwater plankton.
•The EIPATS exhibits controlled and expedited ionic directional pumping transport properties.•The PSR mechanism combining the ion intercalation/deintercalation processes effectively improve the ...extraction efficiency.•The EIPATS contributed Li+/Na+, Li+/K+, and Li+/Mg2+ selectivity up to 242, 870, and 5032 in mixed solution.•The EIPATS displays a high Li-ion flux to 238% of that of no ion-pumping-assisted process.
Enormous demand and limited resources enable Li-ions extraction as emerging research. Herein, we demonstrate how coupled voltage facilitates lithium-selective extraction across a heterogeneous membrane consisting of a glass-type ceramic electrolyte membrane and a stable conductive composite layer. A cell voltage that directs the one-way selective permeation of Li ions is coupled with a pulse voltage that is applied to the conductive layer to accelerate the transmembrane transport of Li ions. This leads to a high Li-ion flux of 124 mmol m−2h−1, which is enhanced to 238% of the flux of no ion-pumping-assisted process. The proposed electrochemical ion-pumping-assisted transfer system (EIPATS) exhibits an excellent ability to extract Li ions from a mixed electrolyte solution, achieving Li+/Na+, Li+/K+, and Li+/Mg2+ selectivity ratios of 242, 870, and 5032, respectively. The proposed EIPATS featuring a heterogeneous membrane anticipates wide potentials in sustainable resource recovery.
The asymmetric ion transport in the nanoconfined space, similar to that of natural ion channels, has attracted broad interest in sensor, energy conversion, and other related fields. Among these ...systems, the surface charge plays an important role in regulating ion transport behaviors. Herein, this surface charge‐regulated asymmetric ion transport behavior is systematically explored in the nanoconfined space and the influence on the performance of nanofluidic energy conversion system. The ion transport behaviors in the nanoconfined space are classified into pure diffusion, electrical double layer, and the polarization controlled state. The asymmetric solution environment or surface charge distribution induces asymmetric ion transport behavior which is largely controlled by the low concentration side. The ion‐selectivity and the energy conversion performance can be effectively enhanced by improving the local apparent surface charge (more active sites and higher charge strength) or introducing a selective layer with dense surface charge on the low concentration side. These material design concepts for asymmetric ion transport are further supported by both simulation and experiment. The results provide a significant comprehension for ion behaviors in nanoconfined space and the development of high‐performance energy storage and conversion systems.
The surface charge plays an important role in regulating nanoconfined ion transport behaviors. The asymmetric surface charge distribution induces asymmetric ion transport behavior, which is largely controlled by the low concentration side. The ion‐selectivity and nanofluidic energy conversion performances can be effectively enhanced by improving the apparent surface charge (more active sites and higher charge strength) on this side.
Crystalline porous covalent frameworks (COFs) have been considered as a platform for uranium extraction from seawater and nuclear waste. However, the role of rigid skeleton and atomically precise ...structures of COFs is often ignored in the design of defined binding configuration. Here, a COF with an optimized relative position of two bidentate ligands realizes full potential in uranium extraction. Compared with the para-chelating groups, the optimized ortho-chelating groups with oriented adjacent phenolic hydroxyl groups on the rigid skeleton endow an additional uranyl binding site, thereby increasing the total number of binding sites up to 150%. Experimental and theoretical results indicate that the uranyl capture is greatly improved via the energetically favored multi-site configuration and the adsorption capacity reaches up to 640 mg g−1, which exceeds that of most reported COF-based adsorbents with chemical coordination mechanism in uranium aqueous solution. This ligand engineering strategy can efficiently advance the fundamental understanding of designing the sorbent systems for extraction and remediation technology.
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•The COFs were used as bio-inspired folded scaffold structure to regulate the configuration of chelating groups.•The COFs with different configurations were synthesized by introducing isomeric building units.•The optimized configuration provides more UO22+ binding sites without redundant chelating groups introduced.•2,3-DhaTat-COF achieved high uranium adsorption capacity of 640 mg∙g−1 and short adsorption equilibrium time.•Selectivity for capturing uranium from nuclear wastewater and seawater.
