Showing papers on "Water environment published in 2015"

Metal–organic frameworks with inherent recognition sites for selective phosphate sensing through their coordination-induced fluorescence enhancement effect

Abstract: Luminescent metal–organic frameworks (LMOFs) have attracted significant attention as a unique class of sensing materials. In this work, the intrinsically fluorescent amino derivative of UiO-66 (UiO-66-NH2) was successfully exploited as a fluorescent probe for the sensitive and selective detection of phosphate anions in an aqueous medium. The inorganic Zr–O clusters and organic BDC-NH2 linkers in the elaborated UiO-66-NH2 MOFs were individually designed as phosphate recognition sites and signal reporters. The intrinsic fluorescence of BDC-NH2 was tuned from high to weak emission by ligand-to-metal charge transfer (LMCT) upon its integration into the framework of UiO-66-NH2 MOFs and this weakened fluorescence could be proportionally recovered in correlation with the applied phosphate level through a newly developed competitive coordination effect. The specificity for phosphate recognition of the employed sensory platform was scarcely affected by other possible interfering species. The efficacy of this strategy was demonstrated by a linear phosphate detection range of 5–150 μM and a limit of detection of 1.25 μM, which was far below the detection requirement of phosphate discharge criteria in the water environment. The possible sensing mechanisms for anionic phosphate detection using the currently established fluorescent probe, including host–guest interaction and structure–property correlation, were systematically investigated using XPS, FT-IR, XRD, TEM and N2 sorption techniques.

Climate change and water in the UK - past changes and future prospects

Abstract: Climate change is expected to modify rainfall, temperature and catchment hydrological responses across the world, and adapting to these water-related changes is a pressing challenge. This paper reviews the impact of anthropogenic climate change on water in the UK and looks at projections of future change. The natural variability of the UK climate makes change hard to detect; only historical increases in air temperature can be attributed to anthropogenic climate forcing, but over the last 50 years more winter rainfall has been falling in intense events. Future changes in rainfall and evapotranspiration could lead to changed flow regimes and impacts on water quality, aquatic ecosystems and water availability. Summer flows may decrease on average, but floods may become larger and more frequent. River and lake water quality may decline as a result of higher water temperatures, lower river flows and increased algal blooms in summer, and because of higher flows in the winter. In communicating this important work, researchers should pay particular attention to explaining confidence and uncertainty clearly. Much of the relevant research is either global or highly localized: decision-makers would benefit from more studies that address water and climate change at a spatial and temporal scale appropriate for the decisions they make.

Cultivation of seaweed Gracilaria in Chinese coastal waters and its contribution to environmental improvements

Abstract: Over the past decade, the large-scale cultivation of seaweed Gracilaria has expanded rapidly in the Chinese coastal waters. The production of Gracilaria increased from 50,536 tons (t, dry weight) in 2003 to 114,722 t in 2010. The production of the seaweed ranks third only to kelps Saccharina (formerly referred to as Laminaria) and Undaria in China. Nan'ao located in Shantou City, Guangdong Province has been successfully developed as one of the major cultivation bases of Gracilaria lemaneiformis at an industrial scale in South China since 2000, and the farmed area increased by 11,538-fold from 0.13 ha in 2000 to 1500 ha in 2011. From lab-scale study to field industrial practice, it has been documented that Gracilaria cultivation is beneficial in environmental improvements such as mitigating eutrophication, controlling harmful algal blooms, maintaining healthy mariculture systems, and sequestrating CO2. Gracilaria may significantly remediate contaminants in mariculture ecosystems and improve the water environment, and its cultivation provides a new approach to coastal environmental improvement in China and the world.

Adsorptive Removal of Pb(II) Ions from Aqueous Samples with Amino-Functionalization of Metal–Organic Frameworks MIL-101(Cr)

Abstract: Metal organic frameworks (MOFs) have been regarded as robust adsorbents for the adsorptive removal of organic pollutants because of their unique characteristics. However, the application of MOFs in the removal of metals from water is still rare. In this paper, amino-functionalization of Cr-based MOFs MIL-101 are modified through coordination bonding of unsaturated Cr metal centers with the -NH2 group in ethylenediamine (ED), and we demonstrate their excellent performance for the removal of Pb(II) ions from water. The Fourier transform infrared verifies that the ethylenediamine was grafted successfully on MIL-101. Furthermore, the results of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy show that the structure of ED-MIL-101 with an appropriate amount of ED almost does not collapse and retains the original performance of MIL-101. The adsorption capacity of ED-MIL-101, which is more than five times that of MIL-101, is 81.09 mg.g(-1) for Pb(II) ions from aqueous samples. The selectivity coefficients of ED-MIL-101 for Pb(II)/Cu(II), Pb(II)/Zn(II), Pb(II)/Co(II), and Pb(II)/Ni(II) are 6.92, 24.02, 15.69, and 14.53, respectively. The adsorption kinetics of Pb(II) ions shows that the process fits well with a pseudo-second-order model, and the adsorption equilibrium time is only about 30 min. Moreover, the practical application of ED-MIL-101 achieves almost 97.22% removal efficiency for Pb(II) ions. These results indicate that ED-MIL-101 has great potential in selectively removing Pb(II) ions from water environment.

Cyber-physical systems for water sustainability: challenges and opportunities

Abstract: Water plays a vital role in the proper functioning of the Earth’s ecosystems, and practically all human activities, such as agriculture, manufacturing, transportation, and energy production The proliferation of industrial and agricultural activities in modern society, however, poses threats to water resources in the form of chemical, biological, and thermal pollution On the other hand, tremendous advancements in science and technology offer valuable tools to address water sustainability challenges Key technologies, including sensing technology, wireless communications and networking, hydrodynamic modeling, data analysis, and control, enable intelligently wireless networked water cyber-physical systems (CPS) with embedded sensors, processors, and actuators that can sense and interact with the water environment This article provides an overview of water CPS for sustainability from four critical aspects: sensing and instrumentation; communications and networking; computing; and control The article also explores opportunities and design challenges of relevant techniques

Microbial indicators, pathogens and methods for their monitoring in water environment.

Abstract: Water is critical for life, but many people do not have access to clean and safe drinking water and die because of waterborne diseases. The analysis of drinking water for the presence of indicator microorganisms is key to determining microbiological quality and public health safety. However, drinking water-related illness outbreaks are still occurring worldwide. Moreover, different indicator microorganisms are being used in different countries as a tool for the microbiological examination of drinking water. Therefore, it becomes very important to understand the potentials and limitations of indicator microorganisms before implementing the guidelines and regulations designed by various regulatory agencies. This review provides updated information on traditional and alternative indicator microorganisms with merits and demerits in view of their role in managing the waterborne health risks as well as conventional and molecular methods proposed for monitoring of indicator and pathogenic microorganisms in the water environment. Further, the World Health Organization (WHO) water safety plan is emphasized in order to develop the better approaches designed to meet the requirements of safe drinking water supply for all mankind, which is one of the major challenges of the 21st century.

Tunable Nanochannels along Graphene Oxide/Polymer Core–Shell Nanosheets to Enhance Proton Conductivity

Abstract: Simultaneous manipulation of topological and chemical structures to induce ionic nanochannel formation within solid electrolytes is a crucial but challenging task for the rational design of high-performance electrochemical devices including proton exchange membrane fuel cell. Herein, a novel generic approach is presented for the construction of tunable ion-conducting nanochannels via direct assembly of graphene oxide (GO)/poly(phosphonic acid) core–shell nanosheets prepared by surface-initiated precipitation polymerization. Using this simple and rapid approach to engineer GO/polymer nanosheets at the molecular-level, ordered and continuous nanochannels with interconnected hydrogen-bonded networks having a favorable water environment can be created. The resulting membranes exhibit proton conductivities up to 32 mS cm−1 at 51% relative humidity, surpassing state-of-the-art Nafion membrane and all previously reported GO-based materials.

Particle size distribution and characteristics of heavy metals in road-deposited sediments from Beijing Olympic Park.

Abstract: Due to rapid urbanization and industrialization, heavy metals in road-deposited sediments (RDSs) of parks are emitted into the terrestrial, atmospheric, and water environment, and have a severe impact on residents' and tourists' health. To identify the distribution and characteristic of heavy metals in RDS and to assess the road environmental quality in Chinese parks, samples were collected from Beijing Olympic Park in the present study. The results indicated that particles with small grain size ( Pb>Cu>Zn. This study analyzed the mobility of heavy metals in sediments using partial sequential extraction with the Tessier procedure. The results revealed that the apparent mobility and potential metal bioavailability of heavy metals in the sediments, based on the exchangeable and carbonate fractions, decreased in the order: Cd>Zn≈Pb>Cu.

Bioinspired transparent underwater superoleophobic and anti-oil surfaces

Abstract: Reported here is a bioinspired fabrication of transparent underwater superoleophobic and anti-oil surfaces using a femtosecond laser treatment. Rough nanoscale structures were readily created on silica glass surfaces by femtosecond laser-induced ablation. Underwater superoleophobicity and ultralow oil-adhesion were obtained by the rough nanostructures with a wide variation of processing parameters, and the as-prepared surfaces exhibited a high transparency in water. This phenomenon is attributed to the presence of the water environment because scattering and refraction are effectively weakened. As a maskless and cost-effective method, the femtosecond laser processing of transparent materials (glass) may provide a new method to create biomimetic transparent underwater surfaces, allowing for the development of novel underwater anti-oil optical devices.

Nature of Absorption Bands in Oxygen-Functionalized Graphitic Carbon Dots

Abstract: Carbon dots (CDs) belong to a class of materials considered technologically important for their tunable absorption and emission properties and a huge application potential in cell labeling, theranostics, and optoelectronic technologies including LED diodes. Although improvement of their properties relies on a fundamental understanding of the underlying photophysical processes, this is currently far from complete. Here, we analyze the absorption spectra of nontrivial multilayer graphitic oxygen-functionalized CD models. The results suggested that the experimentally observed broad bands around 300 nm originated from n → π* and π → π* charge transfer transitions, whereas the effects of structural/energetic disorder, water environment, deprotonation, and excitonic coupling only weakly contributed to the spectra when compared to their monolayer counterparts. Owing to their weak interlayer interactions and thermal accessibility of low-energy conformations, the graphitic CDs are prone to structural disorder and ...

Improved capabilities of the Chinese high-resolution remote sensing satellite GF-1 for monitoring suspended particulate matter (SPM) in inland waters: Radiometric and spatial considerations

Abstract: Dominated by high dynamic and small-scale variability, remote sensing of inland or coastal waters is frequently impended by insufficient spatial resolutions from conventional ocean color sensors With the urgent need and the rapid progress in high-resolution earth observation systems (HR), it is critical to assess the capabilities of HR in inland water monitoring In this study, the radiometric and spatial performance of the Chinese high-resolution GF-1 Wide Field Imager (WFI) data for water quality monitoring were evaluated in term of the signal-to-noise ratio (SNR), sensitivity to suspended particulate matter (SPM) variations and spatial depiction ability The SNR was statistically estimated from variable moving window method, and the radiometric sensitivity was simulated using the Moderate Resolution Atmospheric Transmission (MODTRAN) under varied surface and atmospheric conditions Results indicated that both the SNR and the radiometric sensitivity of the GF-1 WFI were enhanced by 3–5 times than its predecessor (Chinese HJ-1 CCD) or Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and were comparable to Landsat 8 Operational Land Imager (OLI) and Moderate Resolution Imaging Spectroradiometer (MODIS) medium-resolution bands (250 and 500 m), which have been extensively applied in inland water environment monitoring Cross comparisons demonstrated high consistency of the spatial distribution and concentration of SPM maps between GF-1 WFI and Landsat 8 OLI Furthermore, more than 75% of the spatial variations in high turbid waters were resolved from GF-1 WFI data, whereas the ability dropped to 40% when the spatial resolution was degraded to 250 m (MODIS-like sensors) Overall, GF-1 WFI is extraordinarily promising with an enhanced SNR, an increased spectral sensitivity to SPM variations and an advanced spatial resolution With the ongoing plans of the successive GF series (2–7), the findings would serve as a reference for forthcoming applications, and are critical for future satellite missions

Prevalence of Antibiotic Resistance Genes of Wastewater and Surface Water in Livestock Farms of Jiangsu Province, China

Abstract: The overuse of antibiotics in livestock farms is general, leading to a wide distribution of antibiotic resistance genes (ARGs) in aquatic environment adjacent to livestock farms. However, researches of the distribution and types of ARGs in aquatic environment of China are still in the initial stage. In this study, wastewater and surface water samples were collected from 12 livestock farms (four pig farms, four cattle farms, and four chicken farms) in Jiangsu Province of China. The prevalence, abundance, and distribution of 22 ARGs were investigated, which were categorized into six groups, including nine tetracyclin resistance genes, three sulfonamides resistance genes, three quinolone resistance genes, two macrolide resistance genes, three aminoglycoside resistance genes, and two multidrug resistance genes, employing quantitative real-time PCR (qPCR). The results suggested that all of the 22 ARGs were detected in samples. Sul1, sul2, and tetM were the most abundant with the average concentration of 3.84 × 101 copies/16S recombinant RNA (rRNA) gene copies, 1.62 × 101 copies/16S rRNA gene copies, 2.33 × 101 copies/16S rRNA gene copies, respectively. Principle component analysis revealed that the comprehensive pollution of ARGs in northern Jiangsu was more serious. ARGs in wastewater were more abundant when compared to that in surface water. A preliminary study regarding the fate of ARGs after an aerobiotic process showed that tetA, tetC, sul1, sul2, oqxB, and qnrS were significantly increased. And, among the tetracycline resistance genes, the efflux pump genes were enriched while the ribosomal protection protein encoding genes were decreased in the aerobiotic process. The prevalance of ARGs in water environment is of concern; more surveillance is required to determine the pollution level and pattern of antibiotic resistance genes.

The ecotoxicity of graphene family materials: current status, knowledge gaps and future needs

Abstract: Recently, graphene family materials (GFMs) have been introduced among all fields of science and still get numerous attention. Also, the applicability of these materials in many areas makes them very attractive. GFMs have attracted both academic and industrial interest as they can produce a dramatic improvement in materials properties at very low filler content. The aim of this review is to identify, summarize, and present the first available information on the influence of GFMs on soil and water environment as well as identify the knowledge gaps and indicate the directions for the next generation of the original scientific investigations. The paper also presents our first preliminary impact assessment and potential pathways of GFMs distribution in the environment. We used as an example the reduced graphene oxide/Al2O3 nanocomposite (RGO/Al2O3) that has been previously designed and synthesized by us. Authors believe that further work should focus on improvement of characterization methodology applicable for ecotoxicity analyses and possible interactions between GFMs and different living ecosystems. Consequently, the potential impact of graphene and its derivatives on environmental health is a matter of academic interest. However, potential hazards sufficient for risk assessment and concerned with GFMs usage in consumer products first need to be investigated and identified. Further research should focus on gathering knowledge on GFMs properties for life cycle analyses, which still poses a great challenge for scientists.

The implications of climate change for the water environment in England

Abstract: This paper reviews the implications of climate change for the water environment and its management in England. There is a large literature, but most studies have looked at flow volumes or nutrients and none have considered explicitly the implications of climate change for the delivery of water management objectives. Studies have been undertaken in a small number of locations. Studies have used observations from the past to infer future changes, and have used numerical simulation models with climate change scenarios. The literature indicates that climate change poses risks to the delivery of water management objectives, but that these risks depend on local catchment and water body conditions. Climate change affects the status of water bodies, and it affects the effectiveness of measures to manage the water environment and meet policy objectives. The future impact of climate change on the water environment and its management is uncertain. Impacts are dependent on changes in the duration of dry spells and frequency of ‘flushing’ events, which are highly uncertain and not included in current climate scenarios. There is a good qualitative understanding of ways in which systems may change, but interactions between components of the water environment are poorly understood. Predictive models are only available for some components, and model parametric and structural uncertainty has not been evaluated. The impacts of climate change depend on other pressures on the water environment in a catchment, and also on the management interventions that are undertaken to achieve water management objectives. The paper has also developed a series of consistent conceptual models describing the implications of climate change for pressures on the water environment, based around the source-pathway-receptor concept. They provide a framework for a systematic assessment across catchments and pressures of the implications of climate change for the water environment and its management.

Nitrogen fixation in Sphagnum mosses is affected by moss species and water table level

Abstract: Nitrogen (N2) fixation by moss-associated bacteria is an important N source in boreal peatlands and forests. Here we studied whether moss species, water table fluctuations, methane (CH4) availability and diazotroph community structure would affect the rate of Sphagnum-associated N2 fixation. Diazotrophy and methanotrophy were studied in parallel in a double labeling (15 N2 and 13CH4) experiment in forest and fen habitats. The role of N2-fixing methanotrophs was further characterized by the phylogenetic analysis of nifH genes encoding for dinitrogenase reductase. N2 fixation rates were dependent on the moss species in a habitat level, but independent of the diazotroph community structure. Only 6 % of the nifH sequences were taxonomically assigned to cyanobacteria, while the majority (82 %) of genes were assigned to Alphaproteobacteria clustering with the nifH sequences of the order Rhizobiales, but without close matches to sequences of cultivated species. In the originally submerged fen mosses, water increased both N2 fixation and CH4 oxidation rates. However, such effect was not seen in forest mosses grown above the water table level. CH4 addition did not enhance N2 fixation. N2 fixation associated to Sphagnum mosses was controlled by the moss species and the water environment. Although most of the observed nifH sequences were related to the order Rhizobiales, methanotrophs were not responsible for the N2 fixation.

Water ecological carrying capacity of urban lakes in the context of rapid urbanization: A case study of East Lake in Wuhan

Abstract: With the excessive development of social economy, water scarcity and water environment deterioration become a common phenomenon in metropolis. As a crucial component of urban water environment system, urban lake is mainly influenced by social economic system and tourism system. In this paper, a framework for quantitatively evaluating development sustainability of urban lake was established by a multi-objective model that represented water ecological carrying capacity (WECC). And nine key indicators including population, irrigation area, tourist quantity, the average number of hotel daily reception, TP, TN, COD Mn, BOD 5 were chosen from urban social-economy system and natural resilience aspects, with their index weight was determined by using the Structure Entropy Weight method. Then, we took Wuhan East Lake, the largest urban lake in China as a case study, and selected five time sections including 2002, 2004, 2007, 2009 and 2012 to synthetically evaluate and comparatively analyze the dynamic change of WECC. The results showed that: firstly, the water ecological carrying capacity values of the East Lake in five time sections were 1.17, 1.07, 1.64, 1.53 and 2.01 respectively, which all exceeded 1 and increased fluctuation. The rapid growth of population and GDP lead to sharply increasing demand for water quantity. However, a large amount of the domestic sewage and industrial waste led by economic development increases pressure on ecological environment of urban lakes. Secondly, the carrying capacity of the East Lake for tourist activities was still low. The value in 2012 was only 0.22, keeping at a slowly increasing phase, which indicates that the East Lake has large opportunity and space for developing the water resource carrying capacity and could make further efforts to attract tourists. Moreover, the WECC of the East Lake was mainly affected by rapid social and economic development and water environment damage caused by organic pollutants. From the view of urban water sustainable management, we must deeply recognize the reality that water shortages and the limited carrying capacity, and dynamic assessment of WECC provides an early warning approach and control direction of water environment. For the East Lake, it is the primary target to mitigate the carrying capacity of social-economy, especially for prevention of lake area encroachment shrinking and domestic wastewater discharge.

Assessment of water environmental carrying capacity for sustainable development using a coupled system dynamics approach applied to the Tieling of the Liao River Basin, China

Abstract: Water environmental issues result from problems between the socio-economic system and the water environmental system. The concept of water environmental carrying capacity (WECC) can be used to describe water environmental system’s capacity which supports socio-economic development, and examine the trade-off between the driver/pressure (socio-economic) and the support (environmental) components of the societal-environmental interactive system. At the same time, an objective assessment of WECC may provide feasible integrated solutions for resolving water-related environmental problems. Hence, the quantitative assessment of WECC should be based on best available scientific knowledge coupled with appropriate simulation of complex interactions between the society and the environment. For this reason, this paper develops a WECC assessment method (WECC-SDM) which is based on a system dynamics framework. WECC-SDM can dynamically compute the WECC under different societal and environmental scenarios through coevolution and systematic simulations of the society–economy–water environment interactions. The WECC-SDM-based WECC assessment is, in fact, an interactive yet adaptive process of diagnosis–adjustment–improvement, which may provide helpful information for the sustainable development of river basins. The application of WECC-SDM shows that WECC in Tieling (in Northwest China) was severely overloaded in 2012 due to heavy ammonia nitrogen pollution in the dry season, which matches actual observations. The model was subsequently used to predict the situation of Tieling for the next 20 years. However, if positive actions in line with positive socio-economic development are taken to prevent and control pollution, it is possible for Tieling to revert back to a positive WECC situation in 2028, and support a population of 3.17 million and a GDP of 314.8 billion Yuan. As shown by the case study of Tieling, WECC-SDM can make a reasonable assessment of the current situation and simulate the trends of different scenarios, and is thus a practical WECC assessment tool.

Nitrate Accumulation and Leaching in Surface and Ground Water Based on Simulated Rainfall Experiments

Abstract: To evaluate the process of nitrate accumulation and leaching in surface and ground water, we conducted simulated rainfall experiments. The experiments were performed in areas of 5.3 m2 with bare slopes of 3° that were treated with two nitrogen fertilizer inputs, high (22.5 g/m2 NH4NO3) and control (no fertilizer), and subjected to 2 hours of rainfall, with. From the 1st to the 7th experiments, the same content of fertilizer mixed with soil was uniformly applied to the soil surface at 10 minutes before rainfall, and no fertilizer was applied for the 8th through 12th experiments. Initially, the time-series nitrate concentration in the surface flow quickly increased, and then it rapidly decreased and gradually stabilized at a low level during the fertilizer experiments. The nitrogen loss in the surface flow primarily occurred during the first 18.6 minutes of rainfall. For the continuous fertilizer experiments, the mean nitrate concentrations in the groundwater flow remained at less than 10 mg/L before the 5th experiment, and after the 7th experiment, these nitrate concentrations were greater than 10 mg/L throughout the process. The time-series process of the changing concentration in the groundwater flow exhibited the same parabolic trend for each fertilizer experiment. However, the time at which the nitrate concentration began to change lagged behind the start time of groundwater flow by approximately 0.94 hours on average. The experiments were also performed with no fertilizer. In these experiments, the mean nitrate concentration of groundwater initially increased continuously, and then, the process exhibited the same parabolic trend as the results of the fertilization experiments. The nitrate concentration decreased in the subsequent experiments. Eight days after the 12 rainfall experiments, 50.53% of the total nitrate applied remained in the experimental soil. Nitrate residues mainly existed at the surface and in the bottom soil layers, which represents a potentially more dangerous pollution scenario for surface and ground water. The surface and subsurface flow would enter into and contaminate water bodies, thus threatening the water environment.

CO2 Capture and Conversion on Rutile TiO2(110) in the Water Environment: Insight by First-Principles Calculations

Abstract: The conversion of CO2 by the virtue of sunlight has the great potential to produce useful fuels or valuable chemicals while decreasing CO2 emission from the traditional fossil fuels. Here, we use the first-principles calculations combined with the periodic continuum solvation model (PCSM) to explore the adsorption and reactivity of CO2 on rutile TiO2(110) in the water environment. The results exhibit that both adsorption structures and reactivity of CO2 are greatly affected by water coadsorption on rutile TiO2(110). In particular, the solvation effect can change the most stable adsorption configuration of CO2 and H2O on rutile TiO2(110). In addition, the detailed conversion mechanism of CO2 reduction is further explored in the water environment. The results reveal that the solvation effect cannot only greatly decrease the energy barrier of CO2 reduction but also affect the selectivity of the reaction processes. These results presented here show the importance of the aqueous solution, which should be helpful to understand the detailed reaction processes of photocatalysts.