An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
carbon dioxide; carbon radioisotopes, etc ; altitude; crops; fossil fuels; rural areas; China; India; Show all 8 Subjects
Abstract:
... Examining the contribution of fossil fuel CO₂ to the total CO₂ changes in the atmosphere is of primary concern due to its alarming levels of fossil fuel emissions over the globe, specifically developing countries. Atmospheric radiocarbon represents an important observational constraint and utilized to trace fossil fuel derived CO₂ (CO₂ff) in the atmosphere. For the first time, we have presented a ...
carbon; carbon dioxide, etc ; adsorbents; adsorption; carbonization; heat; nitrogen content; polyacrylonitrile; porosity; temperature; China; Show all 11 Subjects
Abstract:
... In this report, nitrogen-doped porous carbons were synthesized from polyacrylonitrile fiber by a facile two-step synthesis process i.e. carbonization followed by KOH activation. Activation temperature and KOH/carbon ratio are two parameters to tune the porosity and surface chemical properties of sorbents. The as-obtained sorbents were carefully characterized. Special attention was paid concerning ...
carbon dioxide, etc ; adsorption; greenhouses; ion exchange; light; photocatalysis; photocatalysts; China; Show all 8 Subjects
Abstract:
... Photocatalytic CO₂ reduction is an appealing strategy for mitigating the environmental effects of greenhouse gases while simultaneously producing valuable carbon-neutral fuels. Numerous attempts have been made to produce effective and efficient photocatalysts for CO₂ reduction. In contrast, the selection of competitive catalysts continues to be a substantial hindrance and a considerable difficulty ...
carbon, etc ; aerosols; air quality; biomass; emissions factor; humans; China; India; Laos; Myanmar; Show all 10 Subjects
Abstract:
... Black carbon (BC) has importance regarding aerosol composition, radiative balance, and human exposure. This study adopted a backward-trajectory approach to quantify the origins of BC from anthropogenic emissions (BCAn) and open biomass burning (BCBB) transported to Xishuangbanna in 2017. Haze months, between haze and clean months, and clean months in Xishuangbanna were defined according to daily P ...
carbon dioxide, etc ; fungi; microbial biomass; toluene; volatile organic compounds; wheat straw; China; Show all 7 Subjects
Abstract:
... As a common practice in agricultural system, straw return has been reported to release a large number of trace gases and attracted much attention. However, the role of straw return in toluene emission remains poorly understood. In this study we measured the emissions of toluene as well as other 50 volatile organic compounds (VOCs) from wheat straw return for 66 days under flooded and non-flooded c ...
carbon, etc ; Pseudomonas; bacteria; caffeine; decaffeination; filtration; manganese dioxide; manganese monoxide; quartz; sand; synergism; China; Show all 12 Subjects
Abstract:
... Bioaugmented sand filtration has attracted considerable attention because it can effectively remove contaminants in drinking water without additional chemical reagent addition. In this study, a synthesized chemical manganese dioxide (MnO₂)-coated quartz sand (MnQS) and biogenic manganese oxide (BioMnOₓ) composite system was proposed to simultaneously remove typical pharmaceutical contaminants and ...
... Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivates (O-PAHs) are identified in soils and groundwater of industrialized sites and contribute to the risk for Humans and the Environment. Nevertheless, data are scarce in literature concerning their retention and transfer in soils and no soil - water partition coefficients are available for these compounds. Sorption of two PAHs, fluo ...
carbon dioxide, etc ; COVID-19 infection; greenhouse gases; river deltas; temporal variation; terrestrial ecosystems; China; Yangtze River; Show all 8 Subjects
Abstract:
... The temporal variation of greenhouse gas concentrations in China during the COVID-19 lockdown in China is analyzed in this work using high resolution measurements of near surface △CO₂, △CH₄ and △CO concentrations above the background conditions at Lin'an station (LAN), a regional background station in the Yangtze River Delta region. During the pre-lockdown observational period (IOP-1), both △CO₂ a ...
... High phosphorus steel slag and carbonized rice husk are two common wastes characterized by high generation and low secondary use values. Through the reduction of high phosphorus steel slag by biomass, both wastes were fully utilized, thus reducing the negative impact on the environment. In this study, variables such as temperature, time, and amount of reactants were changed to determine the optima ...
... Photooxidative removal of pharmaceuticals and organic dyes is an effective way to eliminate growing micropollutants. However, photooxidation often results in byproducts as secondary hazardous substances such as phytotoxins. Herein, we found that photooxidation of common antibiotic tetracycline hydrochloride (TCH) over a metal-free 8-hydroxyquinoline (8-HQ) functionalized carbon nitride (CN) photoc ...
organic carbon, etc ; aerosols; autumn; basins; biomass; cities; coal; combustion; nitrates; particulate emissions; pollution; risk; steel; sulfates; water content; winter; China; Show all 17 Subjects
Abstract:
... Nowadays, the fine particle pollution is still severe in some megacities of China, especially in the Sichuan Basin, southwestern China. In order to understand the causes, sources, and impacts of fine particles, we collected PM₂.₅ samples and analyzed their chemical composition in typical months from July 2018 to May 2019 at an urban and a suburban (background) site of Chengdu, a megacity in this r ...
carbon nitride, etc ; coordination polymers; detection limit; fluorescence; graphene; heavy metals; human health; mercury; quantum dots; semiconductors; spectroscopy; surface area; toxicity; China; Show all 14 Subjects
Abstract:
... The presence of toxic mercury (II) in water is an ever-growing problem on earth that has various harmful effect on human health and aquatic living organisms. Therefore, detection of mercury (II) in water is very much crucial and several researches are going on in this topic. Metal-organic frameworks (MOFs) are considered as an effective device for sensing of toxic heavy metal ions in water. The tu ...
carbon, etc ; Thauera; anaerobic ammonium oxidation; biodegradability; denitrification; long term experiments; microbial communities; models; nitrogen; nitrous oxide production; particulate organic matter; China; Show all 12 Subjects
Abstract:
... In this study, the effects of soluble readily biodegradable COD (sCOD) and particulate slowly biodegradable COD (pCOD) on anammox process were investigated. The results of the long-term experiment indicated that a low sCOD/N ratio of 0.5 could accelerate the anammox and denitrification activity, to reach as high as 84.9%±2.8% TN removal efficiency. Partial denitrification-anammox (PDN/anammox) and ...
carbon, etc ; Monte Carlo method; X-ray diffraction; X-ray photoelectron spectroscopy; adsorption; chlorobenzene; desorption; hydrochars; micropores; models; surface area; tobacco; China; Show all 13 Subjects
Abstract:
... In this work, hydrothermal technique combined with KOH activation were employed to develop a series of porous carbons (NPCK-x) using tobacco stem as a low-cost carbon source and (NH₄)₂C₂O₄ as a novel nitrogen-doping agent. Physicochemical properties of NPCK-x were characterized by Brunauer-Emmett-Teller, field emission scanning electron microscopy, X-ray diffraction, Raman microscope, elemental an ...
total organic carbon, etc ; chlorophyll; lakes; macrophytes; microcystins; nitrates; nitrogen; orthophosphates; phosphorus; phytoplankton; pollution; public health; risk; risk assessment; sediments; total nitrogen; total phosphorus; water management; China; Show all 19 Subjects
Abstract:
... Understanding the history of microcystins (MCs) pollution in large lakes can help inform future lake management. We collected sediment cores from Lake Taihu to: investigate the long-term record of MCs (MC-LR, MC-YR, and MC-RR), explore the main environmental drivers of MCs, and assess their public health and ecological risks. Results showed that MCs content in all cores increased over time. The co ...
carbon, etc ; aerogels; cathodes; cyanides; dielectric spectroscopy; electric current; electric potential difference; electron paramagnetic resonance spectroscopy; hydroxyl radicals; industry; nanorods; oxidation; photocatalysis; singlet oxygen; sulfates; titanium dioxide; wastewater; China; Show all 18 Subjects
Abstract:
... Cyanide (CN⁻) is extensively used in the process of plating devices and for surface treatment in the electroplating industry and is extremely hazardous to humans and the environment. Peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) hold considerable promise for CN⁻ removal. However, the activity of sulfate radical and hydroxyl radical generated in the PMS activation process is low ...
carbon dioxide, etc ; Solanum lycopersicum var. lycopersicum; acoustics; cohesion; data collection; drought; energy; greenhouses; humidity; irrigation; liquids; mathematical models; soil; technology; temperature; tomatoes; transpiration; water conservation; water flow; water requirement; water stress; Show all 21 Subjects
Abstract:
... Precision irrigation is an important component of the water-saving approaches in agriculture and is one of the methods for increasing water-saving efficiency. Detecting water stress in crops accurately is the basis of precision irrigation techniques. In this study, the crop water stress monitoring system was developed to detect the acoustic emission (AE) of plants, associating the three factors of ...
... The cryptomelane-type manganese oxide (OMS-2)-supported Co (xCo/OMS-2; x = 5, 10, and 15 wt.%) catalysts were prepared via a pre-incorporation route. The as-prepared materials were used as catalysts for catalytic oxidation of toluene (2000 ppmV). Physical and chemical properties of the catalysts were measured using the X-ray diffraction (XRD), Fourier transform infrared spectroscopic (FT-IR), scan ...
carbon; carbon fibers; carbon nanofibers, etc ; absorption; carbon nanotubes; energy; nanocomposites; polymers; Show all 8 Subjects
Abstract:
... This paper presents an experimental investigation of the hierarchical strengthening of composite T-shaped bonded joints using dual-length-scale reinforcements: carbon nanomaterials and carbon z-pins. The nanomaterials were carbon nanotubes (CNTs), carbon nanofibres (CNFs) and graphene nanoplatelets (GNPs), which were ∼ 10 nm – 200 μm in length whereas the z-pins were 510 μm (diameter) and 5 mm (le ...
carbon dioxide; carbon sequestration; carbon sinks, etc ; climate; longevity; soil organic carbon; Show all 6 Subjects
Abstract:
... Reversibility of soil carbon sinks is a major obstacle in assigning soil carbon sequestration as negative emission technology and it is still unclear how a non-permanent CO₂ removal shall be accounted for. In this study, we combine various scenarios of reversible and non-reversible soil carbon sinks with atmospheric CO₂ impulse response functions and calculations of the resulting radiative forcing ...