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Результаты 4031-4040 из 4,924
Enhanced adsorption of Cd (II) from aqueous solution by a shrimp bran modified Typha orientalis biochar
2019
Yin, Wenjun | Zhao, Congcong | Xu, Jingtao
The biochar which was characterized with well-developed facial structure and O-/N-containing functional groups could effectively remove Cd (II) from water. In this paper, Typha orientalis–based biochar (BCS) with well-developed N containing functional groups was modified with shrimp bran which was rich in crude protein for the first time. There are more well-developed O-/N-containing functional groups in the structure of BCS than that of pure Typha orientalis–based biochar without any modification (BC), and this conclusion was depended on their comparisons of Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), elemental analysis (EA), Boehm titration, Fourier transform infrared (FTIR), and other characterization techniques. Moreover, according to the experiment, the phenomenon that the adsorption capacity of Cd(II) on these two adsorbents (BCs) decreased with the increase of solution ionic strength could be carried out. The Cd(II) adsorption studies combined with X-ray photoelectron spectroscopy (XPS) analysis revealed that the adsorption mechanism was mainly attributed to physical microporous filtration and chemical interaction between Cd(II) and the surface functional groups (surface complexation, ion exchange, and electrostatic attraction).
Показать больше [+] Меньше [-]Effects of fiscal decentralisation on the environment: new evidence from China
2019
Liu, Liangliang | Li, Linmu
The aim of this paper is to explore the environmental effects of fiscal decentralisation from theoretical and empirical perspectives. We first analyse the dynamic relationship between fiscal decentralisation and the environment using an endogenous growth model. Our findings demonstrate that fiscal decentralisation and environmental pollution display an inverted U-shaped relationship. We then use provincial panel data from 1998 to 2015 in the empirical investigation of CO₂ emissions in China. Our findings show that empirical results verify the correctness of the theoretical results. The results obtained are robust using different methods. The findings of this work may help China’s central government and local governments in addressing the problem of CO₂ emissions by using a reasonable degree of fiscal decentralisation.
Показать больше [+] Меньше [-]Uptake and distribution of phenanthrene and pyrene in roots and shoots of maize (Zea mays L.)
2019
Houshani, Mahdieh | Salehi-Lisar, Seyed Yahya | Motafakkerazad, Ruhollah | Movafeghi, Ali
Polycyclic aromatic hydrocarbons as byproducts of carbon-based fuel combustion are an important group of pollutants with wide distribution in the environment. Polycyclic aromatic hydrocarbons are known as toxic compounds for almost all organisms. Different plant species can uptake polycyclic aromatic hydrocarbons by roots and translocate them to various aerial parts. The aim of this study is to investigate the uptake, translocation, and accumulation of pyrene and phenanthrene in maize under controlled conditions. Seeds were cultivated in perlite containing 25, 50, 75, and 100 ppm of phenanthrene and pyrene, and their concentrations in the roots and shoots of the plants were measured using high-performance liquid chromatography technique after 7, 14, and 21 days. The results revealed that phenanthrene naturally existed in maize and its concentration showed a time-dependent decrease in shoots and roots. In contrast, the concentration of pyrene was increased in the roots and reduced in the shoots. Although pyrene had higher uptake than phenanthrene in roots of maize, the translocation factor value for pyrene was lower than for phenanthrene. According to these findings, phenanthrene could be metabolized in maize in the shoot and root tissues, but pyrene had more tendency to be accumulated in roots.
Показать больше [+] Меньше [-]Does information and communication technologies improve environmental quality in the era of globalization? An empirical analysis
2019
Haseeb, Abdul | Xia, Enjun | Saud, Shah | Ashfaq, Ahmad | Khurshid, Hamid
This study intends to examine the impact of ICTs (i.e., internet usage and mobile cellular subscriptions), globalization, electricity consumption, financial development, and economic growth on environmental quality by using 1994–2014 panel data of BRICS economies. This study employed a second-generation panel unit root test accounting for the presence of cross-sectional dependence and indicated that carbon dioxide emissions, electricity consumption, financial development, internet usage, mobile usage, globalization, and economic growth have integration of order one. The results from Westerlund panel co-integration test confirms that the variables are co-integrated and revealed that ICT-finance-globalization-electricity-GDP-CO₂ nexus has long-run equilibrium relationship. The results from dynamic seemingly unrelated regression (DSUR) indicate that internet usage and mobile cellular subscriptions (ICTs) have significant, adverse impact on carbon dioxide emissions. To put it simply, ICT positively contributes towards environmental quality. Similarly, economic growth also has an adverse effect on carbon dioxide emissions. On the other hand, electricity consumption, globalization, and financial development have a significant positive effect on carbon emissions. In addition, Granger causality test results show the presence of a bidirectional causal relationship between internet usage and environmental quality, financial development and electricity consumption, ICT and financial development, mobile cellular subscription and globalization, economic growth and environmental quality, and internet usage and economic growth. A unidirectional causal link is detected running from mobile cellular subscriptions towards environmental quality, ICT towards electricity consumption, financial development towards environmental quality, globalization towards environmental quality, and globalization towards economic growth. Moreover, time series analysis has also been done in this study to analyze the findings for each of BRICS countries which are directed towards important policy implications. For instance, ICT policy can play an integral part in improving environmental quality policy.
Показать больше [+] Меньше [-]Relationship between arsenic accumulation in tissues and hematological parameters in mullet caught in Faro Lake: a preliminary study
2019
Fazio, Francesco | Saoca, Concetta | Ferrantelli, Vincenzo | Cammilleri, Gaetano | Capillo, Gioele | Piccione, Giuseppe
The authors investigated the arsenic (As) accumulation in different tissues (muscle, gill, liver, stomach, and intestine) and the possible correlation between tissue concentration and hematological parameters in mullet (Mugil cephalus Linnaeus, 1758) caught in Faro Lake (Messina, Sicily, Italy). On all fish, hematological analyses of blood samples, measurement of biometric indices, and the removal of the muscles, gills, liver, stomach, and intestine for the determination of arsenic concentration were performed. A hemogram was performed to find effects of arsenic concentration in tissues on hematological variables. One-way analysis of variance showed significant differences of arsenic concentration in different tissues, with higher values in the gill. The correlation between hematological parameters and tissue arsenic concentration showed a statistical significance for red blood cell (RBC), hemoglobin concentration (Hb), and hematocrit (Hct) with the liver As concentration. Biometric indices (weight, length, and fork length) showed a significant correlation with As concentration of the muscle and liver also. Our results indicate the role of some hematological parameters as biomarkers useful to monitoring anthropogenic load of arsenic in water and sediment, because variations of these parameters represent one of the effects that arsenic exposure can have on fish.
Показать больше [+] Меньше [-]The economic and environmental benefits analysis for food waste anaerobic treatment: a case study in Beijing
2019
Guo, Xiaopeng | Yang, Xiaoyu
The disposal of food waste has attracted worldwide attention. Each year, the amount of wasted food accounts for an estimated one third of annual food production globally. This large amount of food waste has caused serious land, water, and air pollution. In the past, most research on food waste was focused solely on food waste disposal processing. Only a few studies analysed the flow of materials in food waste treatment processes. Therefore, this paper focused on the process of food waste anaerobic treatment in Beijing and investigated the treatment. According to a life cycle theory, the food waste treatment process is divided into three processes: “collection and transportation, disposal, and resource utilization.” This paper analysed the input and output of food waste treatment in different processes and evaluated the economic and environmental costs and benefits of food waste treatment. The study found that 200 t of food waste anaerobic treatment can obtain benefits 66,888 Chinese yuan, generate electricity energy 43,350 kW⋅h, and reduce carbon dioxide emissions 16,087 kg. Generally, the economic and environmental benefits of the food waste anaerobic treatment project are considerable. However, the economic benefits are mainly from government subsidies. There are many impurities in food waste, which indicates some problems in food waste treatment. Thus, the proposals to strengthen waste classification, optimize the layout of garbage collection and transportation, and accelerate the development of waste treatment plants have been put forward.
Показать больше [+] Меньше [-]Effect of irrigation with detergent-containing water on foxtail millet shoot biomass and ion accumulation
2019
Heidari, Hassan | Yosefi, Maliheh | Sasani, Shahryar | Nosratti, Iraj
Water shortage leads farmers to use sewages for irrigation. Sewages contain a large amount of laundry detergent. In this study the impact of irrigation by contaminated water on shoot biomass and seed germination of foxtail millet (Setaria italica) was investigated. The research was conducted as laboratory and pot experiments. Iso-potentials (− 0.042, − 0.077, and − 0.415 MPa) of polyethylene glycol (PEG, water deficit treatment) and laundry detergent (contamination treatment) made the laboratory experiment treatments. The pot experiment included contamination factor (0, 0.1, 1, and 10 g L⁻¹ of laundry detergent) and deficit irrigation factor (irrigation interval of 1, 2, and 3 days). Results of this study showed that at the iso-potential, laundry detergent had more negative effect on seed germination traits when compared with PEG. There was no germination at − 0.415 MPa of laundry detergent. Both drought and contamination reduced dry forage yield, plant height, leaf number, leaf area, leaf dry and fresh weight, stem dry, and fresh weight. Detergent concentration of 10 g L⁻¹ with irrigation interval of 3 days had a forage yield reduction of 63% compared to control (laundry detergent concentration of 0 g L⁻¹ with irrigation interval of 1 day). Detergent concentration of 10 g L⁻¹ with irrigation interval of 1 day had a sodium increase of 1847% compared to control. Based on the results of this study, it is recommended not to irrigate foxtail millet farm by contaminated water with laundry detergent higher than 1 g L⁻¹.
Показать больше [+] Меньше [-]Robust trace analysis of polar (C2-C8) perfluorinated carboxylic acids by liquid chromatography-tandem mass spectrometry: method development and application to surface water, groundwater and drinking water
2019
Janda, Joachim | Nödler, Karsten | Brauch, Heinz-Jurgen | Zwiener, Christian | Lange, F. T.
A simple and robust analytical method for the determination of perfluorinated carboxylic acids (PFCAs) with C₂ to C₈ chains, based on solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), was developed, validated and applied to tap water, groundwater and surface water. Two stationary phases for LC (Obelisc N and Kinetex C₁₈) and two materials with weak anion-exchange properties for SPE (Strata X-AW and Oasis WAX) were evaluated. Robust separation and retention was achieved with the reversed phase column and an acidic eluent. Quantitative extraction recoveries were generally achieved for PFCAs with C > 3, but extraction efficiencies were different for the two shortest chained analytes: 36 to 114% of perfluoropropanoate (PFPrA) and 14 to 99% of trifluoroacetate (TFA) were recovered with Strata X-AW, while 93 to 103% of PFPrA and 40 to 103% of TFA were recovered with Oasis WAX. The sample pH was identified as a key parameter in the extraction process. One-step elution-filtration was introduced in the workflow, in order to remove sorbent particles and minimise sample preparation steps. Validation resulted in limits of quantification for all PFCAs between 0.6 and 26 ng/L. Precision was between 0.7 and 15% and mean recoveries ranged from 83 to 107%. In groundwater samples from sites impacted by per- and polyfluoroalkyl substances (PFASs), PFCA concentrations ranged from 0.056 to 2.2 μg/L. TFA and perfluorooctanoate were the predominant analytes. TFA, however, revealed a more ubiquitous occurrence and was found in concentrations between 0.045 and 17 μg/L in drinking water, groundwater and surface water, which were not impacted by PFASs.
Показать больше [+] Меньше [-]Evaluation of the antifungal activity of individual and combined monoterpenes against Rhizopus stolonifer and Absidia coerulea
2019
Zhou, Lijun | Zhang, Zhilin | Wei, Mi | Xie, Yongjian | He, Shan | Shi, Hongan | Lin, Zhufeng
The development of natural plant extracts and essential oils will help to decrease the negative effects of synthetic chemicals. In the present study, the antifungal activity of individual and combined monoterpenes against Rhizopus stolonifer and Absidia coerulea was evaluated. The results from antifungal tests showed that eugenol, carvacrol, and isoeugenol, among all the tested compounds, exhibited strong antifungal activity against the two tested fungi. Furthermore, carvacrol exhibited the most toxic effects against R. stolonifer and A. coerulea, and the IC₅₀ values of carvacrol for the two fungi were 44.94 μg/ml and 50.83 μg/ml, respectively. The compounds (±)-menthol, b-citronellol, geraniol, 3,7-dimethyl-1-octanol, citral, and cuminaldehyde had only strong antifungal activity against R. stolonifer. In addition, the value of the synergistic co-efficient (SR) of a combination of isoeugenol and eugenol (1:1) showed an additive effect against R. stolonifer. The combination of isoeugenol and cuminaldehyde (1:1) showed an antagonistic effect against A. coerulea. Our results indicated that carvacrol and isoeugenol had potential antifungal effects against the two tested fungi and could be utilized in novel biological fungicide development.
Показать больше [+] Меньше [-]Interactive effect of potassium and flyash: a soil conditioner on metal accumulation, physiological and biochemical traits of mustard (Brassica juncea L.)
2019
Ashfaque, Farha | Inam, Akhtar
At present plants continuously bare to various environmental stresses due to the rapid climate change that adversely affects the growth and nutrient status of the soil and plant. Application of flyash (FA) in combination with potassium (K) fertilizer amendment improves soil physico-chemical characteristics, growth and yield of plants. Mustard grown in combination with FA (0, 20, 40 or 60 t ha⁻¹) and K (0, 30 or 60 kg ha⁻¹) treated soil was used to evaluate the effect on heavy metals (Cd, Cr and Pb) concentration and antioxidant system. The experiment was conducted in a net house of the Department of Botany, Aligarh Muslim University, Aligarh. Sampling was done at 70 DAS. The results showed that concentration of metals was found maximum in roots than the leaf and seeds. FA₆₀ accompanied by K₃₀ and K₆₀ cause oxidative stress through lipid peroxidation and showed reduced levels of photosynthesis and enzymatic activity. Proline and ascorbate content increases with increasing flyash doses to combat stress. However, flyash at the rate of 40 t ha⁻¹ together with K₆₀ followed by K₃₀ significantly boosted crop growth by enhancing antioxidant activity which plays a critical role in ameliorating the oxidative stress. Graphical abstract
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