Reactive oxygen species (ROS) play an essential role in regulating various physiological functions of living organisms. The intrinsic biochemical properties of ROS, which underlie the mechanisms ...necessary for the growth, fitness, or aging of living organisms, have been driving researchers to take full advantage of these active chemical species for contributing to medical advances. Thanks to the remarkable advances in nanotechnology, great varieties of nanomaterials with unique ROS-regulating properties have been explored to guide the temporospatial dynamic behaviors of ROS in biological milieu, which contributes to the emergence of a new-generation therapeutic methodology, i.e., nanomaterial-guided in vivo ROS evolution for therapy. The interdependent relationship between ROS and their corresponding chemistry, biology, and nanotherapy leads us to propose the concept of “ROS science”, which is believed to be an emerging scientific discipline that studies the chemical mechanisms, biological effects, and nanotherapeutic applications of ROS. In this review, state-of-art studies concerning recent progresses on ROS-based nanotherapies have been summarized in detail, with an emphasis on underlying material chemistry of nanomaterials by which ROS are generated or scavenged for improved therapeutic outcomes. Furthermore, key scientific issues in the evolution of ROS-based cross-disciplinary fields have also been discussed, aiming to unlock the innate powers of ROS for optimized therapeutic efficacies. We expect that our demonstration on this evolving field will be beneficial to the further development of ROS-based fundamental researches and clinical applications.
Gold mining not only introduces mercury (Hg) contamination to soils but also facilitates the mobilization of other toxic substances, including arsenic (As). This study assessed the total content, ...chemical species, and bioavailable fraction of As in surface soils impacted by mining residues during frequent flooding. Analysis of 207 soil samples across the floodplain region of La Mojana, Colombia, screened to 2 mm with polyethylene mesh, revealed significant correlations (p < 0.05) between inorganic As, the residual phase, sulphur (S), iron (Fe), manganese (Mn), and aluminum (Al), indicating associations with sulfides and oxyhydroxides of Fe and Mn. The origin of toxicity was linked to suspended materials transported by rivers during flooding in areas with intense mining activity. Sites with better oxidizing conditions exhibited a higher presence of phases associated with amorphous and crystalline oxides in non-flooded areas. Although the bioavailable fraction was minimal in flooded sites, reducing conditions facilitated As mobility, resulting in higher concentrations in deeper soil layers, particularly as As(III). The contamination factor (CF) ranged from 1.3 to 11.1, and the geochemical index (Igeo) ranged from −0.2 to 2.9, indicating a moderate to high As contamination level in soils. This poses potential health risks, considering the agricultural use of these soils.
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•Arsenic speciation and distribution in 207 polluted floodplain soils is assessed.•Floodplain soils are impacted by agricultural, livestock, and mining activities.•Toxicity is linked to suspended materials transported by rivers during flooding.•Arsenic levels rise in soils flooded for 6 months, decreasing with prolonged flooding.•Reducing conditions promote As(III) formation, increasing levels at deeper soil layers.
Adsorption is essential for many processes on surfaces; therefore, an accurate prediction of adsorption properties is demanded from both fundamental and technological points of view. Particularly, ...identifying the intrinsic determinants of adsorption energy has been a long-term goal in surface science. Herein, we propose a predictive model for quantitative determination of the adsorption energies of small molecules on metallic materials and oxides, by using a linear combination of the valence and electronegativity of surface atoms and the coordination of active sites, with the corresponding prefactors determined by the valence of adsorbates. This model quantifies the effect of the intrinsic properties of adsorbates and substrates on adsorbate-substrate bonding, derives naturally the well-known adsorption-energy scaling relations, and accounts for the efficiency and limitation of engineering the adsorption energy and reaction energy. All involved parameters are predictable and thus allow the rapid rational design of materials with optimal adsorption properties.
China is one of the regions with highest PM2.5 concentration in the world. In this study, we review the spatio-temporal distribution of PM2.5 mass concentration and components in China and the effect ...of control measures on PM2.5 concentrations. Annual averaged PM2.5 concentrations in Central-Eastern China reached over 100μgm−3, in some regions even over 150μgm−3. In 2013, only 4.1% of the cities attained the annual average standard of 35μgm−3. Aitken mode particles tend to dominate the total particle number concentration. Depending on the location and time of the year, new particle formation (NPF) has been observed to take place between about 10 and 60% of the days. In most locations, NPF was less frequent at high PM mass loadings. The secondary inorganic particles (i.e., sulfate, nitrate and ammonium) ranked the highest fraction among the PM2.5 species, followed by organic matters (OM), crustal species and element carbon (EC), which accounted for 6–50%, 15–51%, 5–41% and 2–12% of PM2.5, respectively. In response to serious particulate matter pollution, China has taken aggressive steps to improve air quality in the last decade. As a result, the national emissions of primary PM2.5, sulfur dioxide (SO2), and nitrogen oxides (NOX) have been decreasing since 2005, 2006, and 2011, respectively. The emission control policies implemented in the last decade could result in noticeable reduction in PM2.5 concentrations, contributing to the decreasing PM2.5 trends observed in Beijing, Shanghai, and Guangzhou. However, the control policies issued before 2010 are insufficient to improve PM2.5 air quality notably in future. An optimal mix of energy-saving and end-of-pipe control measures should be implemented, more ambitious control policies for NMVOC and NH3 should be enforced, and special control measures in winter should be applied. 40–70% emissions should be cut off to attain PM2.5 standard.
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•In 2013, only 4.1% of the Chinese cities attained the annual average PM2.5 standard.•Secondary inorganic aerosol ranked the highest fraction among PM2.5 species.•National emissions of primary PM2.5 and SO2 have been decreasing since 2005/2006, so as NOX since 2011.•Emission controls make important contributions to decreasing trends in PM2.5 concentrations in megacities.•40–70% emission reduction in the future is needed to attain the PM2.5 standard.
The rapid expansion of biomass power generation has resulted in a large amount of ash, which need to be treated urgently. The trace elements in ash also have environmental risks during treatment. ...Therefore, the essential characteristics and potential environmental risks of biomass ash generated by direct combustion of agricultural straw were studied. The leaching characteristics of elements, including major elements (Mg, K, Ca) and trace elements (V, Cr, Mn, Co, Ni, Cu, Zn, Cd, As, Pb and Ba), in fly ash and slag produced by biomass power plant were analyzed through the static leaching experiments of simulating the possible pH value of natural water in the laboratory. The results show that the trace elements are enriched in fly ash and slag, which may be related to the volatility of elements during combustion. And during the leaching test, the leaching concentration of major and trace elements in fly ash is higher than that in slag. Sequential chemical extraction is used to reveal the occurrence forms of trace elements in biomass ash. Except for residue, Mn, Co, Zn, Cd, and Pb in fly ash mainly exist in carbonate bound, V and As are Fe–Mn oxides bound, and Cr, Ni, Cu, and Ba are mainly organic matter bound. In the slag, Cd is mainly carbonate bound, Cu is mainly organic matter bound, while other elements are mainly Fe–Mn oxides bound. The Risk Assessment Code values calculated based on the existing forms of elements show that As and Cd in slag and Mn, Co, Pb and Cd in fly ash need special attention during utilization. The research results can provide reference for the management and utilization of biomass ash.
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•The toxic leaching concentration of biomass ash is lower than the standard limit.•The major elements and trace elements in biomass ash show different leaching laws.•There are different occurrence forms of elements in biomass ash.•Mn, Co, Cd, Pb in fly ash and As, Cd in slag have potential environmental risks.
The removal of heavy metals from sewage sludge (SS) is attracting increasing attention because the presence of toxic heavy metals in SS restricts its reuse or disposal, especially on land. This ...review presents an overview of research on the origin and chemical speciation of heavy metals in SS and describes methods for their removal. SS primarily absorbs heavy metals from wastewater via passive sorption and active uptake of biomass, resulting in the different chemical speciation. The advantages and disadvantages of the current methods for the removal of heavy metals from SS are analysed. The current methods focus on the removal efficiencies of heavy metals, which are high enough to meet the standard of land application, but the treatment cost, the change and retention of nutrients, and the effects on SS properties resulting from heavy metal removal are usually ignored. In this review, the main knowledge gaps are identified and proposals for future research are made. These should comprise determining the underlying mechanisms of current removal methods, optimising and integrating the removal methods, and establishing systematic evaluation standards for these methods. This review will help researchers develop new environmentally and economically friendly methods for the removal of heavy metals from SS.
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•The origin and chemical speciation of heavy metals in sludge are analysed.•Achievements of current methods for heavy metals removal are overviewed.•Main knowledge gaps of current methods for heavy metals removal are identified.•Future research on removing heavy metals from sewage sludge is proposed.
The main knowledge gaps of the current methods for removing heavy metals from SS are identified and proposals for future research are made.
The removal of heavy metals from water is crucial for human health and the environment, and finding an appropriate adsorption material to achieve this goal is extremely desirable. In this study we ...reported zeolite as the adsorption material to remove the Pb2+ and Ni2+ from the aqueous solution and elucidated the chemical speciation using batch technique. The adsorption of these metals by zeolite was investigated in relation to pH, ionic strength, contact time, co-existing ions, and the temperature. Zeolite exhibited better adsorption capacities than several other adsorption materials, due to its larger specific surface area. The adsorption of Pb2+ and Ni2+ is influenced by ionic strength at pH < 7.0 and pH < 8 and is independent of the ionic strength at pH > 7.0 and pH > 8, respectively. The chemical speciation of Pb2+ and Ni2+ is regulated by outer- and inner-sphere surface complexation, respectively at low and high pH values,. The maximum adsorption capacity of Pb2+ and Ni2+ predicted from the Langmuir model was found to be 45.00 and 28.57 mg g–1 respectively at 303 K. The thermodynamic studies revealed the spontaneous and endothermic nature of adsorption process whereby zeolite displayed an efficient adsorption for both metals with increasing temperature. The findings are very useful in evaluating zeolite interactions in aqueous solutions with the chemical speciation of Pb2+ and Ni2+. From above findings, the zeolite can be recommended as an appropriate adsorbent to adsorb metal ions from aqueous solution.
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•Vanadium history and industrial applications.•Recent research on metal vanadium complexes with amino acids.•Vanadium complexes with amino acids and their properties.•Vanadium complexes are promising ...candidates as metallopharmaceuticals.
In the last 30 years, since the discovery that vanadium is a cofactor found in certain enzymes of tunicates and possibly in mammals, different vanadium-based drugs have been developed targeting to treat different pathologies. So far, the in vitro studies of the insulin mimetic, antitumor and antiparasitic activity of certain compounds of vanadium have resulted in a great boom of its inorganic and bioinorganic chemistry. Chemical speciation studies of vanadium with amino acids under controlled conditions or, even in blood plasma, are essential for the understanding of the biotransformation of e.g. vanadium antidiabetic complexes at the physiological level, providing clues of their mechanism of action. The present article carries out a bibliographical research emphaticizing the chemical speciation of the vanadium with different amino acids and reviewing also some other important aspects such as its chemistry and therapeutical applications of several vanadium complexes.
Complex concentrated solutions of multiple principal elements are being widely investigated as high- or medium-entropy alloys (HEAs or MEAs)
, often assuming that these materials have the high ...configurational entropy of an ideal solution. However, enthalpic interactions among constituent elements are also expected at normal temperatures, resulting in various degrees of local chemical order
. Of the local chemical orders that can develop, chemical short-range order (CSRO) is arguably the most difficult to decipher and firm evidence of CSRO in these materials has been missing thus far
. Here we discover that, using an appropriate zone axis, micro/nanobeam diffraction, together with atomic-resolution imaging and chemical mapping via transmission electron microscopy, can explicitly reveal CSRO in a face-centred-cubic VCoNi concentrated solution. Our complementary suite of tools provides concrete information about the degree/extent of CSRO, atomic packing configuration and preferential occupancy of neighbouring lattice planes/sites by chemical species. Modelling of the CSRO order parameters and pair correlations over the nearest atomic shells indicates that the CSRO originates from the nearest-neighbour preference towards unlike (V-Co and V-Ni) pairs and avoidance of V-V pairs. Our findings offer a way of identifying CSRO in concentrated solution alloys. We also use atomic strain mapping to demonstrate the dislocation interactions enhanced by the CSROs, clarifying the effects of these CSROs on plasticity mechanisms and mechanical properties upon deformation.
Microplastics change the physical, chemical, and biological processes in soil, and these changes further affect the transformations of heavy metal speciation in soil. Whether this influence mechanism ...differs between heavy metals is unknown on the soil aggregates level. In this study, 5 months incubation experiments and soil fractionation were conducted to evaluate the effect of microplastic addition on the chemical speciation of seven heavy metals (Zn, Cu, Ni, Cd, Cr, As, and Pb) in the three soil aggregate fractions. The results show that 28% concentration of polyethylene microplastics with size 100 μm reduces and increases the heavy metal content in the bioavailable and organic-bound fractions, respectively, indicating that microplastics promote the transformation from bioavailable to organic-bound species. The transformation in the larger-sized aggregate fractions is more dramatic than that of smaller-sized aggregate fractions within the incubation period. This indicates that the extent of the response of the different heavy metals to microplastics is significantly different in the three aggregate-size fractions. Soil physicochemical factors affected different heavy metals in different pathways, and microplastics have different adsorption or complexation effects on different heavy metals. These processes result in heterogeneous responses of different heavy metals to microplastic addition. In addition, the microplastics have different extents of influence on the different chemical speciation of the heavy metals, having the greatest influence on the exchangeable and carbonate-bound of Cu and Zn, FeMn oxide-bound of As, and organic-bound of Cr, Ni, Cd, and Pb. This phenomenon is relatively consistent among the three aggregate-size fractions. Our findings provide more accurate management information for soil environmental quality management with different heavy metal pollution and different soil types.
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•Microplastics stimulated heavy metal (HM) transformation from bioavailable to organic bound.•The stimulation degree was different across HMs and soil aggregate fractions.•Microplastics affected HM speciation through direct adsorption and changing soil properties.•pH and DOC were significant factors affecting HM speciation in the presence of microplastics.
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