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Removal of antibiotics from aqueous solutions by nanoparticles: a systematic review and meta-analysis Texte intégral
2019
Malakootian, Mohammad | Yaseri, Mehdi | Faraji, Maryam
Antibiotics, as one of the emerging pollutants, are non-biodegradable compounds and long-term exposure to them may affect endocrine, hormonal, and genetic systems of human beings, representing a potential risk for both the environment and human health. The presence of antibiotics in surface waters and drinking water causes a global health concern. Many researches have stated that conventional methods used for wastewater treatment cannot fully remove antibiotic residues, and they may be detected in receiving waters. It is reported that nanoparticles could remove these compounds even at low concentration and under varied conditions of pH. The current study aimed to review the most relevant publications reporting the use of different nanoparticles to remove antibiotics from aqueous solutions. Moreover, meta-analysis was conducted on the results of some articles. Results of meta-analysis proved that different nanoparticles could remove antibiotics with an acceptable efficiency of 61%. Finally, this review revealed that nanoparticles are promising and efficient materials for degradation and removal of antibiotics from water and wastewater solutions. Furthermore, future perspectives of the new generation nanostructure adsorbents were discussed in this study.
Afficher plus [+] Moins [-]Characterizations and mechanisms for synthesis of chitosan-coated Na–X zeolite from fly ash and As(V) adsorption study Texte intégral
2019
Han, Caiyun | Yang, Ting | Liu, Hang | Yang, Liu | Luo, Yongming
Solid waste fly ash with low aluminum of Yunnan Province in China was used as pristine material to prepared chitosan-coated Na–X zeolite, and the obtained composite material was employed as As(V) adsorbent. Then, the prepared materials were characterized by XRD, FT-IR, and XPS. And the results suggested that the low aluminum fly ash was successfully convert into Na–X zeolite, and the mineralization between Si–OH of the obtained Na–X zeolite and C–OH of chitosan was the dominated mechanism for coated chitosan over the surface of Na–X zeolite. From the batch experiments of As(V) removal, it has been found that the coated chitosan could significantly improve As(V) performance of Na–X zeolite. The optimal working pH for removal As(V) by chitosan-coated Na–X zeolite was attained at pH 2.1 ± 0.1, and the maximum adsorption capacity was 63.23 mg/g. And the adsorption data at different interval time was excellent fitted by pseudo-second-order kinetic model. From the analyze of XPS, the results suggested that As(V) uptake over adsorbent by the bond of As–N and As–O and the surface hydroxyl group of Al–OH and –NH₂ were involved in uptake As(V) from acid wastewater.
Afficher plus [+] Moins [-]Efficient removal of dyes from dyeing wastewater by powder activated charcoal/titanate nanotube nanocomposites: adsorption and photoregeneration Texte intégral
2019
Lin, Yingchao | Ma, Jun | Liu, Wen | Li, Zeyu | He, Kai
Effective removal of dyes has been widely investigated by the adsorption of powder activated carbon and photodegradation by titanate nanotubes (TNTs). In this study, a facile one-step alkaline-hydrothermal method was applied to synthesize powder activated charcoal–supported TNTs (TNTs@PAC). Adsorption of three representative dyes, i.e., cationic methylene blue (MB), cationic rhodamine B (RhB), and anionic methyl orange (MO), onto TNTs@PAC was evaluated by the adsorption kinetic experiments and adsorption isotherms. The first 30 min is the main time phase of adsorption, and MB, RhB, and MO obtained the experimental equilibrium uptake of 173.30, 115.06, and 106.85 mg/g, respectively, indicating their final removal efficiencies of 100%, 69.36%, and 64.11%, respectively. The increase of pH value reduced adsorption capacity of MO (from 149.35 mg/g at pH of 2 to 96.99 mg/g at pH of 10), but facilitated MB adsorption, which was attributed to the charge distribution on the surface of TNTs@PAC and the charge of dyes at different pH. Furthermore, good capacity recoveries of MB by TNTs@PAC (> 99%) were observed after UV irradiation treatment, indicating the used TNTs@PAC can be easily recycled for the adsorption of MB by UV irradiation. Overall, TNTs@PAC is an effective process for remediation of dye-contaminated water because of its adsorption performance for all selected dyes and good regeneration capacity for MB.
Afficher plus [+] Moins [-]Constructing magnetic Pt-loaded BiFeO3 nanocomposite for boosted visible light photocatalytic and antibacterial activities Texte intégral
2019
Jaffari, Zeeshan Haider | Lam, Sze Mun | Sin, Jin Chung | R̲ahmān, Eṃ. Ē.
Visible light–responsive Pt-loaded coral-like BiFeO₃ (Pt-BFO) nanocomposite at different Pt loadings was synthesized via a two-step hydrothermal synthesis method. The as-synthesized photocatalyst was characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence (PL) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and magnetic hysteresis loop (M-H loop) analyses. The FESEM images revealed that Pt nanoparticles were evenly distributed on the coral-like BFO. The UV–vis DRS results indicated that the addition of Pt dopant modified the optical properties of the BFO. The as-synthesized Pt-BFO nanocomposite was effectively applied for the photodegradation of malachite green (MG) dye under visible light irradiation. Specifically, 0.5 wt% Pt-BFO nanocomposite presented boosted photocatalytic performance than those of the pure BFO and commercial TiO₂. Such a remarkably improved photoactivity could be mainly attributed to the formation of good interface between Pt and BFO, which not only boosted the separation efficiency of charge carriers but also possessed great redox ability for significant photocatalytic reaction. Moreover, the strong magnetic property of the Pt-BFO nanocomposite was helpful in the particle separation along with its great recyclability. The radical scavenger test indicated that hole (h⁺), hydroxyl (·OH) radical, and hydrogen peroxide (H₂O₂) were the main oxidative species for the Pt-BFO photodegradation of MG. Finally, the Pt-BFO nanocomposite was revealed high antibacterial activity towards Bacillus cereus (B. cereus) and Escherichia coli (E. coli) microorganisms, highlighting its potential photocatalytic and antibacterial properties at different industrial and biomedical applications.
Afficher plus [+] Moins [-]The asymmetric effect of air quality on cross-industries’ stock returns: evidence from China Texte intégral
2019
Su, Chi-Wei | Wang, Kai-Hua | Tao, Ran | Lobonţ, Oana-Ramona
This paper offers a perspective for the link between air quality and stock returns in China through quantile Granger causality test. Compared to previous studies, the study makes the following innovations. Given the Chinese government plays an important role in economic development, its industrial policies are regarded as a new indispensable supplement of analysis framework apart from investor mood. Next, due to different reflections from cross-industries for different AQ levels, the industry heterogeneity is further considered. Also, nine industries are chosen as a sample, including environmental protection, wind power equipment, steel, photovoltaic equipment, thermal power, tourism, coal, medical service, and medical equipment. Besides, the quantile Granger causality test is robust to misspecification errors when detecting the potential dependence structure between the variables of air quality and stock returns. The empirical results show that the causal link exists in all industries, except medical service. Meanwhile, this impact presents asymmetrical features that when air quality is unhealthy, it has an influence on stock returns of the remaining eight industries. It can be explained by increasing cortisol level, more stringent environmental protection, and industrial policies. These conclusions have essential implications for market participants due to the fact that air quality generates various influences on the stock market. That is why a sustainable environmental design, strict regulatory framework, and special monitoring activities should be highly regarded in China.
Afficher plus [+] Moins [-]Eichhornia crassipes biodiesel as a renewable green fuel for diesel engine applications: performance, combustion, and emission characteristics Texte intégral
2019
Venu, Harish | Venkataraman, Dhinakaran | Purushothaman, Prince | Vallapudi, Dhana Raju
This work examines the feasibility of fuelling biodiesel derived from Eichhornia crassipes in a compression ignition engine. This work also proposes water hyacinth biodiesel (WHB) as a potential alternative energy source since the above species is available extensively in freshwater, marine, and aquatic ecosystems throughout the world. WHB was blended with petroleum diesel fuel at various volume proportions of 10%, 20%, 30%, 40%, and 100% and their properties were analyzed as per ASTM standards for its application as biofuel. The prepared test fuels were analyzed experimentally in a single-cylinder diesel engine at constant speed (1500 rev/min) for its performance, combustion, and emission characteristics. Test results projected that the characteristics of 20% WHB + 80% diesel fuel blend were in par with neat diesel fuel in terms of thermal efficiency, HC, CO, and smoke emissions. However, WHB blends resulted in slightly higher levels of CO₂ and NOx emissions. At full load, the attained cylinder pressure and heat release rate of WHB were comparatively lower than diesel fuel. Ignition delay is lowest for B100 blend and therefore the diffusion burning phase of biodiesel phase is found to be dominant in comparison with diesel fuel. For biodiesel blends, the combustion starts earlier due to higher cetane number, lessened delay period, and lowered calorific value followed by lowered HRR. Graphical abstract
Afficher plus [+] Moins [-]Correction to: Monte Carlo fingerprinting of the terrestrial sources of different particle size fractions of coastal sediment deposits using geochemical tracers: some lessons for the user community Texte intégral
2019
Gholami, Hamid | Jafari Takhti Najad, Ebrahim | Collins, Adrian L. | Fathabadi, Aboalhasan
The original publication of this paper contains a mistake. The correct University name of the 3rd affiliation is shown in this paper.
Afficher plus [+] Moins [-]A two decades study on ozone variability and trend over the main urban areas of the São Paulo state, Brazil Texte intégral
2019
Schuch, Daniel | de Freitas, Edmilson Dias | Espinosa, Sergio Ibarra | Martins, Leila Droprinchinski | Carvalho, Vanessa Silveira Barreto | Ramin, Bruna Ferreira | Silva, Jayne Sousa | Martins, Jorge Alberto | de Fatima Andrade, Maria
In this paper, we analyze the variability of the ozone concentration over São Paulo Macrometropolis, as well the factors, which determined the tendency observed in the last two decades. Time series of hourly ozone concentrations measured at 16 automated stations from an air quality network from 1996 to 2017 were analyzed. The temporal variability of ozone concentrations exhibits well-defined daily and seasonal patterns. Ozone presents a significant positive correlation between the number of cases (thresholds of 100–160 μg m⁻³) and the fuel sales of gasohol and diesel. The ozone concentrations do not exhibit significant long-term trends, but some sites present positive trends that occurs in sites in the proximity of busy roads and negative trends that occurs in sites located in residential areas or next to trees. The effect of atmospheric process of transport and ozone formation was analyzed using a quantile regression model (QRM). This statistical model can deal with the nonlinearities that appear in the relationship of ozone and other variables and is applicable to time series with non-normal distribution. The resulting model explains 0.76% of the ozone concentration variability (with global coefficient of determination R¹ = 0.76) providing a better representation than an ordinary least square regression model (with coefficient of determination R² = 0.52); the effect of radiation and temperature are the most critical in determining the highest ozone quantiles.
Afficher plus [+] Moins [-]A study of the predictive factors of mortality in acute poisoning with aluminum phosphide with special reference to echocardiography and SOFA score Texte intégral
2019
Sheta, Abeer A. | El-Banna, Asmaa S. | Elmeguid, Rania Abd | Mohamed, Hany E. | Gad, Nehad H.
Aluminum phosphide (AlP) is considered now one of the most common causes of poisoning among agricultural pesticides. Poisoning with AlP is extremely toxic to humans with high mortality rate. The aim of this work was to evaluate the prognostic factors and outcome of acute aluminum phosphide poisoning in Alexandria Main University Hospital during a period of 6 months from 1 November 2017 until the end of April 2018, highlighting the role of SOFA score and echocardiography in predicting the mortality. The prospective study was conducted on all patients admitted with acute AlP poisoning to Alexandria Main University Hospital for those 6 months. Patients’ data were collected in a special sheet and included biosocial data, medical history, poisoning history, complete medical examination, investigations, duration of hospital stay, and the outcome. All patients were assessed according to SOFA score on admission. Thirty patients were admitted during the period of the current study. Females outnumbered males in all age groups with a sex ratio of 2.75:1. The mean age of patients was 22.77 ± 12.79 years. 96.6% of patients came from rural areas. 93.3% of the cases were exposed to poisoning at home, where suicidal poisoning accounted for (86.7%) of cases. 43.3% of patients died (n = 13), and the median value of SOFA score among non-survivors was 10, versus 1 among survivors. The median value of ejection fraction among non-survivors (25%) was half its value in survivors (50%). Although there were many predictors of severity of AlP poisoning, SOFA score was the most predictive factor of mortality detected by multivariate analysis.
Afficher plus [+] Moins [-]Investigating the urbanization process and its impact on vegetation change and urban heat island in Wuhan, China Texte intégral
2019
Gui, Xuan | Wang, Lunche | Yao, Rui | Yu, Deqing | Li, Chang’an
Rapid urbanization significantly changes vegetation coverage and heat distribution, which threatens the sustainable development and the quality of life. As the largest developing city in Central China, Wuhan was chosen as the experimental region. This study investigated the urbanization process of Wuhan from 1989 to 2917 based on Landsat data. Combined with MODIS EVI (Enhanced Vegetation Index) and LST (Land Surface Temperature) data, vegetation disturbance and surface urban heat island (SUHI) caused by urbanization were discussed for 2001–2017. Furthermore, correlation between ∆EVI (urban EVI minus rural EVI) and ∆LST (urban LST minus rural LST) was also conducted. The results were as follows: (1) Wuhan experienced a strong urbanization over the past 29 years, with an increasing urban expansion rate and the altered dominant urban expansion pattern (edge expansion and infilling). After the enhanced vegetation functions and urban increased structures, the urbanization finally caused the fragmented patches and irregular urban shapes. (2) Urbanization had a positive effect on LST but a negative effect on EVI. From 2001 to 2017, the highest increasing rate of ∆LST for the old urban area (OUA) and urbanized area (UA) was both observed in summer daytime (OUA, 0.106 °C/a; UA, 0.207 °C/a). The decreasing rate of ∆EVI reached the highest value in summer (OUA, 0.00697/a; UA, 0.00298/a). (3) There was a strong negative correlation (except spring and winter for OUA) between ∆EVI and ∆LST in daytime, which proved that the activity of vegetation in daytime could relieve LST to a certain extent. This study clarifies the dynamic urbanization process of Wuhan and discusses its impacts on vegetation change and SUHI. Efficiently investigating urbanization process and quantifying its impacts on urban environment are critical for regional ecological conservation.
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