Higher Water Yield Research Articles

Superstructure-Enabled Anti-Fouling Membrane for Efficient Photothermal Distillation

Photothermal membrane distillation (MD) combining solar harvesting and heat localization is a rapidly emerging technology for water purification and desalination. However, state-of-the-art photothermal MD still suffers from several issues in membrane fouling, material instability, poor long-term performance, and complex synthesis. Herein, we demonstrate a multilevel-roughness membrane by immobilizing a nanoparticle-assembled superstructure on a nanofibrous membrane to obtain omniphobic surface wettability. The nanoparticle-assembled superstructure with abundant nano-/microchannels and low surface energy simultaneously captures solar energy, repels chemical/oil-based contaminants, and facilitates vapor flow. The unique mechanism based on the effects of the multilevel-roughness structure allows effective control of surface wettability, leading to a successful photothermal MD application, highlighted by highly efficient solar-thermal conversion, excellent antifouling behavior, and durability. A high clean water yield of 9.01 kg m–2 h–1 is obtained at a solar intensity of 10 kW m–2, corresponding to a solar-water efficiency of 66.8%. More importantly, when operating in complex feed-water conditions, including oil contaminated and high-saline solution, the speed of clean water generation still presents excellent stability over 48 h of consecutive operation, which significantly outperforms the commercial distillation membranes (typically 1 h). Multiple merits of efficient solar-thermal conversion and long-term stability, supported by techno-economic and scalability analyses, make the composite membrane promising for clean water generation from diverse contaminant mixtures in the solar-driven MD system.

Vertically Aligned Janus MXene-Based Aerogels for Solar Desalination with High Efficiency and Salt Resistance.

Solar desalination is an effective way of converting solar energy to heat for seawater purification. The structure of absorbers and salt resistance are two crucial parameters for water transport and desalination stability. Here, we designed a vertically aligned Janus MXene aerogel (VA-MXA) with hydrophobic upper layer and hydrophilic bottom layer. Compared with irregular porous channels, such regulatable and well-ordered vertical array structure gives competitive advantage in the capillary water transport, light absorption, and vapor escape. MXene, which possesses a theoretical light-to-heat conversion efficiency of 100%, combined with the Janus structure, can efficiently convert light to heat and prevent the photothermal layer from "direct bulk water contact" with the hydrophobic upper layer, thus decreasing heat loss, while the hydrophilic bottom layer submerged in water can quickly pump water upward through the vertically aligned channels with low transport resistance and, meanwhile, enable effective inhibition of salt crystallization due to rapid dissolution with continuously pumping water. With a vertically aligned and Janus structure by flexible design, the Janus VA-MXA exhibited a high conversion efficiency (87%) and stable water yield for 15 days (∼1.46 kg·m-2·h-1) under 1 sun. About 6 L·m-2 of freshwater was output daily from seawater.

Fast microwave-assisted hydrolysis of unsaturated polyester resin into column packing for rapid purifying of dye wastewater

Microwave-assisted selective degradation successfully converts thermosetting unsaturated polyester resins into a low-swelling (below 10 g g−1) gel material (GM) with a high yield (58–65%) in water at 100°C for only 1 h. The obtained GM possesses rough and porous structure while the content of carboxylate group obtained by cleavage of partial ester groups is more than 10%, varying with the concentration of the catalyst. It is suitable for use as packing of adsorption column to rapidly purify sewage. Super high filtering rates of 18582–27002 L h−1 m−3 without external pressure and high removal efficiency of more than 99.8% were achieved, promoting practical application for rapid removal of organic pollutants.

Insights from watershed simulations around the world: Watershed service-based restoration does not significantly enhance streamflow

Increased water yield and baseflow and decreased peak flow are common goals of watershed service programs. However, is the forest management often used in such programs likely to provide these beneficial watershed services? Many watershed service investments such as water funds typically change less than 10% of watershed land cover. We simulate the effects of 10% forest-cover change on water yield, low flow, and high flow in hydrologic models of 29 watersheds around the world. The forest-cover changes considered are: forest restoration from degraded natural lands or agriculture, forest conversion to agriculture, and forest conversion to urban cover. We do not consider grassland restoration by removal of alien tree species from riparian zones, which does increase water yield and low flow. Forest restoration from locally-predominant agricultural land resulted in median loss in annual water yield of 1.4%. Forest restoration reduced low flow and high flow by ∼3%. After forest restoration, low flow increased in ∼25% of cases while high flow and water yield declined in nearly all cases. Development of forest to agriculture or urban cover resulted in a 1–2% median increase in water yield, a 0.25–1% increase in low flow, and a 5–7% increase in high flow. We show that hydrologic responses to forest cover changes are not linearly related to climate, physiography, initial land cover, nor a multitude of watershed characteristics in most cases. These results suggest that enhanced streamflow watershed services anticipated from forest restoration or conservation of 10% or less of a watershed are generally modest.

Solar Energy Conversion: Multifunctional Solar Waterways: Plasma‐Enabled Self‐Cleaning Nanoarchitectures for Energy‐Efficient Desalination (Adv. Energy Mater. 30/2019)

In article number 1901286, Zheng Bo and co-workers produce on-surface waterways by integrating hydrophilic on-surface light-absorbers and hydrophobic internal thermal-insulators into an all-carbon nanoarchitecture with self-cleaning and anti-salt-fouling behavior. The heat conduction loss for solar desalination is thus suppressed, achieving high solar-vapor efficiency, high daily clean water yield, and long-term stability.

Effect of reducibility of transition metal oxides on in-situ oxidative catalytic cracking of tar

To understand the effect of reducibility of transition metal oxides (TMOs) on tar conversion, four TMOs including Fe2O3, MnOx, CuO, and NiO were selected and in-situ oxidative catalytic cracking of coal pyrolysis tar on a two-stage fixed bed reactor at 550 °C was performed. The reducibility of TMOs was measured by H2-temperature programmed reduction (H2-TPR). The effect of reducibility of TMOs on the pyrolysis products distribution and conversion was investigated. The changes of TMOs before and after reaction were also analyzed by several characterizations. The addition of TMOs results in the decrease of tar yield and heavy tar content, and the increase of gas yield. The reduction temperature of TMOs affects the products distribution and heavy tar conversion. Among these four TMOs, Fe2O3 shows the highest reduction temperature (390–700 °C with peak centered on 570 °C) and the largest heavy tar conversion (75.3 wt%). CuO shows the lowest reduction temperature (190–470 °C with peak centered on 326 °C) and heavy tar conversion (45.8 wt%). The main reactions on CuO is complete oxidation with high water yield (12.8 wt%) and CO2 formation (110 mL/g.coaldaf). The coke formed on the used Fe2O3 is amorphous or disordered carbon, and shows the largest yield being 5.5 wt%.

Experimental research on four-stage cross flow humidification dehumidification (HDH) solar desalination system with direct contact dehumidifiers

A novel Four-stage cross flow humidification and dehumidification (HDH) solar desalination system with direct contact dehumidifiers was proposed in this paper. Firstly, the composition and operation principle of the system were introduced. Then, the heat and mass exchange models of main parts in the system were established, and some indexes to evaluate system performance were given. Next, an indoor experiment was set up and tested. Based on the experimental results, this paper analyzed the effects of seawater spraying temperature, spraying quantity and the air volume flow rate on freshwater production rate and the gain output ratio (GOR). Finally, the economic analysis and freshwater yield per unit volume of this system were discussed. The results show that when Ts1 = 83 °C, ms1 = 1.1 t/h and mc1 = 0.94 t/h, the water yields of the HDH system with 560 m2 total heat transfer area are 47 kg/h and 63 kg/h respectively under V·a = 0 m3/h and V·a = 300 m3/h. Compared with conventional systems, the current system has higher water yield per unit volume (34.1 kg/(m3·h)) and lower pure water yield cost (3.86 $/ton) when the investment cost of the whole solar desalination device with 42 m2 solar collectors is about $ 6563.

Cover Feature: Optimization of Aqueous Stability versus π‐Conjugation in Tetracationic Bis(triarylborane) Chromophores: Applications in Live‐Cell Fluorescence Imaging (Chem. Eur. J. 32/2019)

Anthracene as bulky linker: Changing the steric demand of the linker between two dicationic BAr2 groups leads to water-soluble and water-stable quadrupolar tetracationic cell-imaging agents. With anthracene as the linker, stability as well as π-conjugation between the two boron π-acceptors was achieved, resulting in a very high fluorescence quantum yield in water (0.86). Furthermore, its use as a lysosomal imaging agent was demonstrated. More information can be found in the Full Paper by S. Yamaguchi, T. B. Marder et al. on page 7679.

Half‐sandwich ruthenium‐based versatile catalyst for both alcohol oxidation and catalytic hydrogenation of carbonyl compounds in aqueous media

A series of half‐sandwich ruthenium‐based catalysts for both alcohol oxidation and carbonyl compounds hydrogenation have been synthesized through metal‐induced C–H bond activation based on benzothiazole ligands. The neutral ruthenium complexes 1–4 were fully characterized by UV–vis, NMR, IR, and elemental analysis. Molecular structures of complexes 1 and 3 were further confirmed by X‐ray diffraction analysis. All complexes exhibited high activity for the catalytic oxidation of a variety of alcohols with tBuOOH as oxidants to give carbonyl compounds with high yields in water. Moreover, these half‐sandwich complexes also showed high efficiency for the catalytic hydrogenation of carbonyl compounds in a methanol–water mixture. The catalyst could be reused for at least five cycles without any loss of activity. The catalytic system also worked well for various kinds of substrates with either electron‐donating or electron‐withdrawing groups.

PVP-templated highly luminescent copper nanoclusters for sensing trinitrophenol and living cell imaging.

Copper nanoclusters (CuNCs) exhibit susceptibility to oxidation in the subnanometer size range. In this work, a facile and green protocol is reported for the successful synthesis of water soluble CuNCs, with poly(vinylpyrrolidone) as a template and ascorbic acid as a mild reducing agent. The as-prepared CuNCs exhibit a green fluorescence and high quantum yield (QY = 44.67%) in water, which is the highest among the reported water soluble CuNCs. The origin of their highly luminescent nature was also investigated. In addition, the obtained CuNCs show good tolerability to high ionic strength, superior antioxidation properties, good photostability, time-stability, a large Stokes shift and ultralow cytotoxicity, laying the foundation for living cell imaging in THP-1 macrophages. A bright green fluorescence can be observed from the cells, indicating the potential practicality of CuNCs as a fluorescence marker in bioapplications. Interestingly, the as-prepared CuNCs exhibit a good selective fluorescence quenching response towards trinitrophenol over other nitro compounds. Furthermore, CuNCs were employed for sensing trinitrophenol based on the inner filter effect. A good linear relationship was obtained in the low concentration range of trinitrophenol, with a limit of detection of 3.91 × 10-7 M in aqueous medium. This result suggests the potential application of CuNCs as a probe in sensing and monitoring toxic trinitrophenol in the field of environmental security.

Mapping water yield distribution across the South Athabasca Oil Sands (SAOS) area: Baseline surveys applying isotope mass balance of lakes

Study regionSurveys of stable isotopes of water in 121 lakes were conducted between 2007 and 2009 to assist in characterizing baseline hydrology of the South Athabasca Oil Sands area, Alberta, a 35,000 km2 boreal forest region with subdued relief, about 70% wetland cover, and a mosaic of lakes, rivers and buried channel networks. The region, currently under rapid development for in-situ oil sands, was close to baseline conditions at the time of survey. Study focusUsing an isotope mass balance approach, isotope data were applied to estimate water yield to lakes across the region. High-resolution maps were created to illustrate the spatial distribution of water yield and to compare observed patterns to geologic and physiographic features. New hydrological insights for the regionSite-specific differences in water yield were found in relation to geologic and physiographic features. Notably, high water yields were found in lakes underlain by Colorado shale, lower runoff was found in proximity to incised and buried channels. Consistent patterns from year-to-year reveal zones of low runoff which may be more susceptible to development-related impacts including changes in surface/groundwater interaction and pressurization or depressurization of aquifers or formations. The approach may be helpful for informing design of new monitoring programs to ensure runoff variability is considered. Periodic reassessments are recommended to capture potential development and/or climatic change impacts on the water cycle.

Calculation model for water influx and controlled reserves for CBM wells with high water yield

Compared with conventional gas reservoir, percolation mechanism of coalbed methane (CBM) is completely different, it is remarkably affected by adsorption/desorption performance, pressure variation and coalbed characteristics. Then it is difficult to calculate the controlled reserves of CBM wells. Moreover, the connection of edge-bottom water or interbedded water by fractures or faults may largely increase the water yield and drainage period, leading to obvious water invasion in some CBM wells. There are few literature about the predicted production for CBM wells with high water yield. Focusing on the unconventional CBM reservoir, methods of pseudo geological reserves and production index curves are adopted to establish the calculation model of water influx and controlled reserves. It further confirms that the calculation model is successfully applicated on the CBM wells at the middle part of Qinshui Basin in China.

Woody bioenergy crop selection can have large effects on water yield: A southeastern United States case study

Short-rotation woody crops in the southeastern United States will make a significant contribution to the growing renewable energy supply over the 21st century; however, there are few studies that investigate how species selection may affect water yield. Here we assessed the impact of species selection on annual and seasonal water budgets in unvegetated plots and late-rotation 14–15-year-old intensively managed loblolly pine (Pinus taeda L.) and sweetgum (Liquidambar styraciflua L.) stands in South Carolina USA. We found that while annual aboveground net primary productivity and bioenergy produced was similar between species, sweetgum transpiration was 53% higher than loblolly pine annually and 92% greater during the growing season. Canopy interception was 10.5% of annual precipitation and was not significantly different between the two species. Soil evaporation was less than 1.3% of annual precipitation and did not differ between species, but was 26% of precipitation in unvegetated plots. Annual water yield was 69% lower for sweetgum than loblolly pine, with water yield to precipitation ratios of 0.13 and 0.39 for sweetgum and loblolly pine, respectively. If planted at a large scale, the high transpiration and low water yield in sweetgum could result in declines in downstream water availability relative to loblolly pine by the end of the growing season when storage in groundwater, streams, and water supply reservoirs are typically at their lowest. Our results suggest that species selection is of critical importance when establishing forest plantations for woody bioenergy production due to potential impacts on downstream water yield.

Quantifying and mapping of water-related ecosystem services for enhancing the security of the food-water-energy nexus in tropical data–sparse catchment

The food-water-energy nexus concept helps to produce an integrative solutions to secure the water-related ecosystem services sustainably. This study aims to quantify and map water provisioning and soil erosion regulating services from both demand and supply sides in a spatially explicit manner. It considers the Wabe River catchment of the Omo-Gibe Basin in tropical data-sparse region of East Africa as a case study and uses the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) annual and seasonal water yield and sediment delivery models. The water demands and biophysical parameters data were collected from primary and secondary sources and prepared according to the requirement of the models. The models output were validated after conducting sensitivity analysis of the input parameters. The result shows that the rainfall amount of the catchment is highly seasonal, which causes the surface water to vary according to the seasons. The high annual precipitation and low actual evapotranspiration of the catchment resulted high annual water yields. However, the people in the catchment did not satisfied their domestic water demand as result of inaccessibility and poor management of the rain water. The high net supply of water, especially in the rainy season, carries detached top soil via heavy rainfall in the upper catchment areas. Even though the existing land cover and management practices contribute to sediment retention, a large amount of sediment is exported to rivers, which jeopardizes the food and energy security. Thus, the management of water is essential for enhancing the security of the food-water-energy nexus in the catchment. The methods applied in this study can increase spatial understanding of the water-related ecosystem services especially in data–sparse catchments of the tropics, and lead to improvement of water management to enhance the security nexus.

Antibacterial Assessment of Heteroaryl, Vinyl, Benzyl, and Alkyl Tetrazole Compounds

In previous reports, the antibacterial properties of certain tetrazole derivatives have been described. We have previously reported the antibacterial properties of aryl 1Htetrazole compounds. To study the antibacterial activity of 5-substituted heteroaryl, vinyl, benzyl, and alkyl 1H-tetrazole derivatives. The antibacterial properties of heteroaryl, vinyl, benzylic, and aliphatic tetrazole derivatives were investigated against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The activity was assessed by determining the minimum inhibitory concentration of these tetrazole derivatives and comparing them to the known antibiotics amoxicillin, trimethoprim and sulfamethoxazole. The tetrazole compounds were prepared utilizing cerium(III) chloride heptahydrate catalysis at 160 °C for 1-4 h in a microwave reactor using an aqueous solvent mixture. The most active derivatives exhibited minimum inhibitory concentration values between 125-250 µg/mL against Escherichia coli. More importantly, these compounds were considerably more active when used in combination with trimethoprim and a significant synergistic effect was observed (MIC = 0.98-7.81 µg/mL) against E. coli and S. aureus. The tetrazole derivatives were synthesized in high yield and short reaction times in water. Several of the tetrazole compounds showed a significant synergistic antibacterial effect when used with trimethoprim.

Biocatalytic conversion of 5-hydroxymethylfurfural: Synthesis of 2,5-bis(hydroxymethyl)furan and 5-(hydroxymethyl)furfurylamine

Two different green biocatalytic methods were investigated for the transformation of 5-hydroxymethylfurfural (HMF) to valuable disubstituted furan derivatives. 2,5-bis(hydroxymethyl) furan (BHMF) was obtained by biocatalytic reduction using lyophilized plant tissues. 5-(hydroxymethyl)furfurylamine (HMFA) was synthesized by amination transfer reaction catalysed by immobilized transaminase enzymes. By choosing suitable reaction conditions both products were obtained with high yields in water as reaction medium, at room temperature or 50 °C within a reaction time of 48 and 24 h. The studied protocols represent environmentally benign and promising green catalytic processes, generating less waste than other synthetic approaches.

Domestic wastewater treatment by forward osmosis-membrane distillation (FO-MD) integrated system

In this study, real domestic wastewater treatment by forward osmosis-membrane distillation (FO-MD) integrated system was investigated in laboratory scale. The integrated membrane system presented a good separation performance and the removal efficiency of most contaminants in the domestic wastewater was higher than 90%. High molecular weight contaminants were completely removed, while a few low molecular weight contaminants permeated through the membrane. The FO membrane fouling layer mainly consisted of organic substances like polysaccharides and proteins, and was very loose and could be effectively removed by rinsing the membrane surface with tap water. By comparison, the MD membrane fouling was mainly induced by inorganic salts and was not as severe as that of the FO membrane. During 120 h continuous operation, the FO-MD integrated system exhibited satisfying performance stability and maintained a high water yield and high product water quality. The results indicated the potential of the FO-MD integrated system for municipal wastewater treatment in coastal cities, water purification and desalination.

Precursor control over the self-assembly of [2]catenanes via hydrazone condensation in water.

By means of hydrazone condensation, a series of homo-[2]catenanes were self-assembled in high yields in water. The properties of the precursors have a great impact on the self-assembly pathway, as well as the stability and co-conformations of the products.

A Continuous Directional Solvent Extraction Desalination Process Realized with the Aid of Electro-coalescence

The recently demonstrated non-membrane, low-temperature directional solvent extraction (DSE) is promising toreduce desalination cost by eliminating the need of membranes and utilizing low-temperature energy sources fromsolar energy or waste heat. This paper investigates the technical feasibility of a continuous DSE water desalinationprocess using decanoic and octanoic acid as directional solvents (DS). A continuous lab-scale DSE prototype isrealized with the aid of electro-coalescence (EC) with a capacity of producing 28 ml/h of freshwater. A preliminaryeconomic analysis shows that the operational cost of DSE desalination is estimated to be ~$3.03/m3. Our resultsreveal two critical technological aspects that need further research to push DSE closer to deployment. These include(1) identifying more effective DSs with higher water yield; (2) optimizing the EC to improve the separation efficiencyand effectiveness. Both aspects will be critical to increase water production rate and decrease energy cost of DSEdesalination. Our cost analysis indicates that the desalination cost of DSE can reach ~$0.25/m3, if the DSperformance can be improved by four-folds and the EC efficiency is increased to 90%. In summary, the current worklays a framework upon which further research on the continuous DSE desalination process can be based. Once it ismature and widely deployed, DSE is promising to lower the desalination cost by utilizing low-temperature wasteheat, which will contribute significantly to ameliorating the global water scarcity problem.

Rehabilitation of hydrological functioning of paramo ecosystems in Colombia

Paramos are equatorial alpine ecosystems characterized by a high air humidity, frequency of fog and the presence of shrub and herbaceous vegetation adapted to the specific equatorial alpine conditions. Under natural conditions these ecosystems present a high water yield, among other ecosystem services, however, this changes when they are degraded. Despite their importance, they are ecosystems that have been modified by man, most of them even without having been studied. This paper presents the results of a hydrological research carried out in three paramos in Colombia, which evaluates their hydrological functioning and their capacity for recovery once they are altered. Therefore, we studied their climate, hydrology, and soils properties. Results indicate that these ecosystems have different climatic conditions, which determine their water yield and water regulation. Differences in the hydro-physical properties of soils and organic matter content, which determine differences in their capacity to retain water and on the magnitude of the water available for plants. These results indicate that undisturbed paramos or with a low degree of disturbance present high water yield and good water regulation; and intervened paramos can recover the natural conditions of soil properties, and consequently their hydrological functioning, even in a few decades.