Preparation and characterization of <Emphasis Type="Italic">β</Emphasis>-FeOOH-coated sand and its adsorption of Cr(VI) from aqueous solutions

Batch adsorption experiments were conducted to explore the adsorption of Cr(VI) in aqueous solutions by β-FeOOH-coated sand. We investigated the key factors which affected the adsorption process such as adsorbent dosage, initial pH, initial Cr(VI) ion concentration, contact time and temperature. The uptake of Cr(VI) was very rapid and 44.3%, 51.6%, 58.9% of the adsorption happened during the first 180 minutes at 293K, 303K and 313K, respectively. The pseudo-second-order rate equation successfully described the adsorption kinetics. To study the adsorption isotherm, two equilibrium models, the Langmuir and Freundlich isotherms, were adopted. At 293K, 303K and 313K, the adsorption capacities obtained from the Langmuir isotherm were 0.060, 0.070 and 0.076 mg Cr(VI) per gram of the adsorbent, respectively. Thermodynamic parameters such as the change of energy, enthalpy and entropy were calculated using the equilibrium constants. The negative value of ΔG ⁰ and the positive value of ΔH ⁰ showed that the adsorption of Cr(VI) in aqueous solutions by β-FeOOH-coated sand was spontaneous, endothermic and occurred by physisorption.     

Biosorption of Cr(VI) from wastewater using Sorghastrum Nutans L. Nash

Sorghastrum Nutans L. Nash is used as an adsorbent for the removal of Cr(VI) from wastewater. Adsorption coupled reduction i.e. indirect reduction is the mechanism of Cr(VI) removal by the biomaterial. The adsorbent surface became highly positively charged at lower pH, adsorption rate of Cr(VI) is faster and reduction reaction also accelerates at lower pH since the binding of negatively charged Cr(VI) ion species to the cationic groups is enhanced and protons take part in this reaction. The adsorbent is characterised by using XRD, FTIR, SEM and EDAX analysis. OH bending, CN stretching/bending and NH stretching play a major role in Chromium adsorption. Experimental values follow pseudo-second order reaction and Langmuir adsorption isotherm. Surface diffusion is the rate controlling mechanism for the process. The maximum percentage of Cr(VI) removal obtained is 75.5% with 7?g/L dosage at pH 1.3 and adsorbate concentration was 100?mg/L. From the normal probability, residual, contour, 3D surface, main effect and interaction plot along with t-test, ANOVA, and F-test, it is observed that pH has the most significant effect on the percentage removal followed by adsorbent dosage and time. The adsorbate concentration has the least effects and interaction effects are found to be significant.     

Mechanochemical synthesis of oxygenated alkynyl carbon materials with excellent Hg(Ⅱ) adsorption performance from CaC2 and carbonates

Adsorptive removal of heavy metal ions from wastewater is very important, and the key is the development of efficient sorbents. In this work,oxygenated alkynyl carbon materials(OACMs) were synthesized via mechanochemical reaction of CaC₂ and a carbonate(CaCO₃, Na₂CO₃, or NaHCO₃) at ambient temperature. The resultant OACMs are micro mesoporous carbon nanomaterials with high specific area(>648 m²g^-1),highly crosslinked...     

Printed in great Britain Cr(VI) and other metallic mutagens in fly ash and welding fumes†

Particulate samples taken from both the indoor (working) and outdoor (community) environments contain a wide range of metallic trace elements most of which are mutagenic in at least one of the short term tests for genotoxicity currently in use. Because of the demonstrated presence of a short lived biologically active species (Cr(VI)), and the uncertainty with which the results of the screening of metallic compounds in short term tests can be interpreted in terms of human risk, great care must be taken to assure the appropriate collection, storage, and chemical and biological assay of such material. The sensitivity of the results for fly ash and welding fumes to variations in these protocols is demonstrated and discussed.     

Effect of Ca(II), Fe(II), and Fe(III) on Cu(II) adsorption by a polyvinylidene fluoride-based chelating membrane from Cu(II)–EDTA complex solution

A polyvinylidene fluoride-based membrane bearing the diethylenetriaminepentaacetic acid chelating group was employed to recover Cu(II) from the Cu(II)-ethylenediaminetetraacetic acid complex aqueous solution. Effects of Ca(II), Fe(II), and Fe(III) on Cu(II) uptake were investigated by static batch adsorption tests and dynamic adsorption filtration. Isotherms, kinetics, and breakthrough curves of Cu(II) uptakes in the presence of the three cations at concentrations of 1 mmol L^?1 were elucidated. The three cations showed a positive effect on the Cu(II) uptake; the stimulative roles were in the order of Fe(III) > Fe(II) > Ca(II). They did not alter the adsorption behavior of the membrane; adsorption isotherms and kinetics could be described by Langmuir and Lagergren second-order models, and Cu(II) adsorption was a spontaneous and exothermic process. The presence of Ca(II), Fe(II), and Fe(III) increased the sorption capacity of the membrane stack by 1.3, 1.9, and 3 times. Breakthrough time and the exhaustion time of membrane stacks were also extended.     

The international register of potentially toxic chemicals (IRPTC) its databank and network partners∗

The IRPTC was established by UNEP in 1976, upon the recommendation of the United Nations Conference on the Human Environment held in Stockholm in 1972.

It consists of a central unit and a network for information exchange. The main objective of IRPTC is to provide information adequate for the assessment of the hazards to health and the environment posed by chemicals. It is designed primarily to assist authorities responsible for protection of human health and the environment; however, its services are available to everyone.     

Synthesis and antifungal property of N,N′-bis(trans-cinnamaldehyde)-1,2-diiminoethane and its derivatives

N,N′-bis(trans-cinnamaldehyde)-1,2-diiminoethane and its derivatives were designed and synthesized. Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (¹H-NMR) techniques were applied to characterize chemical structures, and the filter paper disk method was used to test for antifungal effect of the products against Aspergillus niger, Paecilomyces variotii, and Paecilomyces lilacinus. Chemical structure charaterization showed that the products are target compounds. Antimicrobial experiment results indicated that N,N′-bis(trans-cinnamaldehyde)-1,2-diiminoethane displayed reliable antifungal effects against three fungi, and its antifungal effect is close to that of cinnamaldehyde. N,N′-bis(p-methoxy cinnamaldehyde)-1,2-diiminoethane and N,N′-bis(p-chlorocinnamaldehyde)-1,2-diiminoethane also showed antifungal effects at a low concentration. Of the two, N,N′-bis(p-methoxy cinnamaldehyde)-1,2-diiminoethane appeared to be more suitable as it was more effective at higher concentrations against Paecilomyces.     

A revised calculation of the econometric factors α- and β for the Extended Exergy Accounting method

Extended Exergy Accounting (“EEA”) is a method to compute the space- and time integral of the primary exergy required to produce a good or a service: the extended exergy of a commodity measures its “embodied exergy”, including externalities (Labour, Capital and Environmental Costa). A crucial point of the method is the calculation of two econometric coefficients, commonly referred to as “α” and “β”,used to calculate the extended exergy equivalents of Labour and Capital respectively. In previous applications of the EEA method, these coefficients have been assigned approximate values estimated on the basis of global system considerations. In this paper, a novel procedure is described that leads to the calculation of “exact” values of both econometric coefficients, based on detailed exergy- and monetary balances of the Society to which the EEA is applied. It is shown that both α and β depend in a non-trivial way from the consumption patterns, the technological level and the life- and socio-economic standards of each Country. It is also shown that the values are substantially different for developed (OECD) and underdeveloped Countries, and representative samples of values are calculated and critically analysed. On the basis of these new model coefficients, the specific exergy equivalents of Labour (ee_L) and of Capital (ee_K) are calculated, and shown to differ from the values used in previous EEA calculations.     

Hydrochemical and radiometric evaluation of fresh and thermal waters from Araxá city (Minas Gerais,Brazil)

Environmental Geochemistry and Health - This paper reports the hydrochemistry and activity concentration of the natural radionuclides 238U, 234U, and 210Po for three compartments of the...     

Growth pattern andβ-dimethylsulphoniopropionate (DMSP) content of green macroalgae at different irradiances

Growth rates and intracellular-dimethylsulphoniopropionate (DMSP) concentrations of five green algal species collected from different geographic regions in 1986 and 1989 were determined under four photon flux rates. InUlothrix implexa, U. subflaccida andAcrosiphonia arcta from Antarctica, growth was light-saturated at lower irradiances than in temperateUlva rigida from Southern Chile andBlidingia minima from Germany. The DMSP content ofUlothrix implexa, A. arcta andUlva rigida was directly correlated with the light factor: with increasing irradiance, algal DMSP level increased. In contrast, inUlothrix subflaccida andB. minima DMSP concentrations gradually decreased up to a photon flux rate of 30µmol m^–2 s^–1, then increased markedly under the highest photon flux rate tested. In non-growing, dark-incubatedA. arcta DMSP content was reduced by 35%, while the DMSP pool of all other species remained unchanged, at the level of pre-culture conditions. Under full darkness all plants exhibited a significantly higher DMSP concentration compared with algae grown at low photon flux rates of 2 to 30µmol m^–2 s^–1. These data show a correlation between growth pattern and DMSP biosynthesis, and may point to a species-specific minimum amount of light energy necessary for DMSP accumulation.Contribution no. 302 of the Alfred Wegener Institute of Polar and Marine Research     

以NH2-MIL-53(Al)为前驱体制备多孔掺碳Al2O3吸附剂及其对水中Cr(Ⅵ)的吸附性能

铬是污染性金属元素,铬含量是水质污染控制的一项重要指标,其中Cr(Ⅵ)的毒性最大,且易被人体吸收.本研究以水中的Cr(Ⅵ)吸附传质分离为目标,利用以铝为金属源水热法合成的铝基MOFs为前驱体,600℃煅烧后制备了多孔掺碳Al₂O₃吸附材料,利用现代分析技术对其进行微观结构表征,探究了其吸附作用能力与机制.研究结果表明,XRD、SEM、BET等表征手段证明了NH₂-MIL-53(Al)与多孔掺碳Al₂O₃结构的成功合成.前驱体NH₂-MIL-53(Al)和煅烧后的衍生物多孔掺碳Al₂O₃,在形貌上相似,且多孔掺碳Al₂O₃材料(180.24 m²·g^-1)的比表面积要大于NH₂-MIL-53(Al)(116.73 m²·g^-1).多孔掺碳Al₂     

Spatial segregation of calving and nursing Risso’s dolphins (Grampus griseus) in the Azores,and its conservation implications

Calving can be a critical period for cetaceans. Areas providing security for vulnerable calves, and high food availability for lactating females can be critical habitats requiring specific conservation measures. Here, we test the hypothesis that calving and nursing habitat could be defined for Risso’s dolphins (Grampus griseus). We investigated the spatial and temporal preferences of this species around Pico Island, Azores, using data gathered from land-based surveys and dedicated at-sea observations between 2004 and 2007. We divided observed pods into three groups: (1) those with newborn and young calves, (2) those with older calves or juveniles and (3) those consisting only of adults or sub-adults. We analysed eco-geographical variables and incorporated them into a presence-only spatial distribution model to evaluate differences in habitat suitability among the groups. We identified 694 pods of Risso’s dolphins overall. On the 267 pods observed in the first and second groups, 136 calves or juveniles were identified, of which 22 were newborns. The peak of the calving season was between June and August. The pods with newborn calves were larger and closer to shore, whereas the other groups were more widely dispersed offshore. Our results support the definition of critical habitat areas for this species, but we suggest widening the geographical coverage for better mapping around the island and throughout the archipelago generally. Conservation measures can, nevertheless, be implemented immediately, in order to reduce human impacts on a vulnerable component of the Risso’s dolphin population     

The concentration of Cu and Pb in the funnel spider Eratigena atrica (C. L. Koch 1843) (Araneae: Agelenidae) and its web

Studies on the heavy metal concentrations on spider webs in relation to the pathways of pollution penetration (external and internal) have yet to be performed. This work assesses the concentration levels of two heavy metals: essential copper (Cu) and toxic lead (Pb) in spider webs and spiders (females, males and juveniles). Spiders divided into three treatment groups were exposed to the heavy metals in their diet as prey (fruit flies and mealworms larvae) were artificially contaminated with Cu and Pb. In general, we found higher rates of Cu compared to Pb concentrations in spiders and their webs. A positive correlation between levels of Cu and Pb in webs and spiders was found. Males had higher concentrations of both metals Cu and Pb in their bodies and webs compared to females. In an additional experiment, washed webs had significantly less metals than unwashed suggesting the dominance of external pollution in the contamination pathway.     

Purification and characterization of an endo-1, 4-β-D glucanase from the cellulolytic system of the wood-boring marine mollusk<Emphasis Type="Italic"> Lyrodus pedicellatus</Emphasis> (Bivalvia: Teredinidae)

The soluble fraction of crude tissue homogenates prepared from intact specimens of the shipworm Lyrodus pedicellatus Quatrefages was observed to increase the reducing sugar content of solutions of carboxymethylcellulose (CMC). The predominant CMCase activity detected in these lysates by zymography corresponds to a polypeptide of approximately 40 kDa. This protein, designated Lp-egl-1, was purified and characterized. Experiments described in this study were performed in 1997 using L. pedicellatus from a culture maintained at the Woods Hole Oceanographic Institution. Purified Lp-egl-1 increases reducing sugar content of solutions of CMC and suspensions of phosphoric acid–swollen cellulose, decreases viscosity of CMC solutions, and cleaves the oligosaccharides cellopentaose and cellotetraose internally to release cellotriose and cellobiose. It has no detectable activity against microcrystalline cellulose, cellotriose, cellobiose, or p-nitrophenyl -D-glucopyranoside and does not release glucose from any tested substrate. These results are consistent with the conclusion that Lp-egl-1 is an endo-1, 4--D glucanase (E.C. 3.2.1.4). The K _m value of Lp-egl-1 for CMC is 20 mg ml^–1. The enzymatic activity is inhibited by cellobiose and cellotriose, but not by glucose. Lp-egl-1 differs in molecular mass as well as kinetic and immunological properties from a previously described endoglucanase secreted by a cultivable endosymbiont of shipworms, Teredinibacter turnerae Distel et al., 2002. It has not been determined whether Lp-egl-1 is a product of the L. pedicellatus nuclear genome or of an associated symbiotic microbe.Communicated by J.P. Grassle, New Brunswick     

Research progress of nitrous oxide reductase gene (nosZII) and its relationship with the environment北大核心CSCD

The greenhouse effect has become increasingly serious globally. Nitrous oxide (N2O) is both the major ozone depleting substance and a potent greenhouse gas having a global warming potential 298 times that of CO2, and the N2O concentration is still increasing at an annual rate of about 0.8 × 10-9. Nitrous oxide reductase (N2OR) can reduce N2O to N2, and until recently, the nosZ gene was the only gene known to be able to encode N2OR. Besides the well-known nosZI, a new lineage of the N2O-reductase (nosZ clade II), which is abundant and widespread in soils, has been identified. In this paper, the main characters of nosZII-containing microbial communities and the related working mechanisms are summarized. In addition to the main differences between nosZI and nosZII, the important environmental factors that regulate the composition, abundance, and expression of nosZII-containing communities are also discussed in this paper. Studies have shown that nosZII communities are distributed among a diverse range of bacterial and archaeal phyla, such as Epsilon-proteobacteria, Bacteroidetes, and Aquificae. Interestingly, most of the nosZII microbes lack a nitrite reductase encoding gene (nirS or nirK) and are therefore unable to denitrify, indicating the importance of these communities as N2O sinks. Soil properties such as texture, pH, C/ N ratio, temperature, and lake physical gradient could regulate nosZII microbe abundance and diversity, and the pH and C/ N ratio may be the most important influencing factors. Studies on the ecological function of nosZII microbes have advanced considerably with the development of molecular biology technology. However, further studies on the community structure of nosZII microbes, the influencing factors of nosZII microbe abundance and diversity, and characteristics of nosZII strains with strong N2O reducing ability are needed. We hope to provide a theoretical basis that can be used to facilitate N2O reduction and relieve the greenhouse gas problem. © 2018 Science Press. All rights reserved.     

Removal of selenite using ‘waste’ Fe(III)/Cr(III) hydroxide: Adsorption kinetics and isotherms

Removal of selenite [Se (IV)] from aqueous solution on to industrial solid ‘waste’ Fe(III)/Cr(III) hydroxide as adsorbent was investigated in the present article. Maximum adsorption was found to be at pH 4.0. Pretreated Fe(III)/Cr(III) hydroxide was found to be more efficient for the removal of selenite compared to untreated adsorbent. Langmuir and Freundlich isotherms have been studied. The Langmuir adsorption capacity (Q ₀) of the pretreated and untreated adsorbents was found to be 15.63 and 6.04?mg?g^?1, respectively. The adsorption process fit into the second-order kinetics. Thermodynamic parameters show that the adsorption process is spontaneous and endothermic in the temperature range 32 to 60°C. Coexisting anions vanadate and phosphate significantly affect the adsorption of selenite for both the pretreated and untreated adsorbents. Molybdate, thiocyanate, sulphate, nitrate and chloride do not significantly affect the removal of selenite for pretreated adsorbent.     

Soxhlet extraction parameters’ influence on the recovery of polychlorinated dibenzo‐p‐dioxins and dibenzofurans (PCDD/F) from a sediment,and artifact formation of PCDD

Soxhlet extraction of polychlorinated dibenzo‐p‐dioxins/dibenzofurans (PCDD/F) from sediment was studied using a designed experimental set‐up. Three variables were studied: three solvent combinations n‐hexane/methanol, dichloromethane/acetone and toluene/methanol; two extraction times, 8 and 16 h, and addition of bulk substances (sodium carbonate). The extraction efficiency was almost identical in all extractions, with the exception of extraction where toluene/ methanol was combined with sodium carbonate. In these samples a major effect was observed, due to formation of Hx‐, Hp‐ and OCDD isomers. Composition of formed PCDD was similar to PCDD isomers found in pentachlorophenol products.     

The effects of developmental lead (Pb) exposure on the expression of the CTGF and TGF-β1 in hippocampus of pups

Pregnant mice were exposed to control (0%), low (0.1%), moderate (0.5%), and high (1%) lead (Pb) acetate in deionized drinking water from the first day of gestation to postnatal day (PND) 21. Pb concentration was determined in blood and the hippocampus at the 7th, 14th, or 21st day of neonatal mice pups. The expression of connective tissue growth factor (CTGF) and TGF-β1 mRNA and protein was also measured in the hippocampus using RT-PCR and immunohistochemistry assays. The expression of CTGF and TGF-β1 mRNA was up-regulated in hippocampus in Pb-exposed groups. These results were further confirmed by immunohistochemistry staining. Data suggest that CTGF and TGF-β1 genes are differentially regulated and are affected by Pb.