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Synergistic effect of adsorption and photocatalysis for the degradation of toluene by TiO2 loaded on ACF modified by Zn(CH3COO)2 Texte intégral
2021
Activated carbon fiber (ACF) was modified by Zn(NO₃)₂, ZnCl₂, and Zn(CH₃COO)₂), respectively, and then, TiO₂ was loaded on the modified ACFs. The adsorption and photocatalysis performance were explored through the removal of toluene, and TiO₂/ACF-Ac modified by Zn(CH₃COO)₂) with the best toluene degradation performance was selected. The characterization results of a scanning electron microscope (SEM), X-ray diffraction spectra (XRD), and Fourier transform infrared spectrometer (FTIR) indicated that the samples were rough, and TiO₂ was mainly loaded on the surface containing large amount of oxygen-containing functional groups in anatase phase. An ultraviolet-visible diffuse reflectance spectrophotometer (UV-vis DRS) revealed that the catalyst enhanced the light response range. The photoelectric chemical experiment results demonstrated that the modified ACFs remarkably improved the charge transmission and the separation efficiency of electrons and holes. The adsorption saturation time reached 40 h and toluene photodegradation rate was 70%. Four toluene degradation intermediate products were determined by GC-MS, and the removal mechanism of toluene by TiO₂/ACF-Ac was discussed.
Afficher plus [+] Moins [-]Association between phthalate exposure and insulin resistance: a systematic review and meta-analysis update Texte intégral
2021
An update on systematic review and meta-analysis was performed to explore effects of phthalate exposure on insulin resistance. A systematic literature search was performed in MEDLINE, Web of Science, and CNKI until March 2021. A conceptual framework was constructed to guide the organization and presentation of results. Besides, beta coefficients with corresponding confidence intervals were extracted from the most adjusted models. Extracted beta coefficients were transformed into correlation, and z Fisher transformation of correlation with the corresponding standard error was included in meta-analysis. Subgroup analyses were performed by age (adult vs. adolescent) and sex (female vs. male) of participants and site of study (America and Europe vs. Asia) to explore potential sources of heterogeneity. Nineteen literatures with 12,533 participants reporting on the association of exposure to specific phthalates and insulin resistance were selected. The majority of included studies revealed positive relationships of insulin resistance with different phthalate metabolites exposure. Meta-analyses were performed on 16 studies. Exposure to MnBP, MBzP, MCPP, MEHP, MEOHP, MEHHP, ∑DEHP, and high-molecular weight phthalate (∑HMWP) was associated with the increase of the homeostasis model assessment of insulin resistance (HOMA-IR) index. The results of sensitivity analyses stratified by age, sex, and site of study remained stable, suggesting the robustness of these meta-analyses. Most of heterogeneity in sensitivity analyses decreased to moderate or low degree. Exposure to MnBP, MBzP, MCPP, MEHP, MEOHP, MEHHP, ∑DEHP, and ∑HMWP was associated with the increased risk of HOMA-IR. Age, sex, and site of study might provide limited source of heterogeneity.
Afficher plus [+] Moins [-]A new route to select the referable values of property indicators for normalization and its application in screening polymeric membrane heavy metal (Co, Ni, and Cr)-ion-selective electrodes with multiple high-response performances Texte intégral
2021
Distance to target normalization may not be suitable to select the referable values, (RC)ᵣₑfₑᵣ, and responsive characteristic (RC) indicators, for the electrode comprehensive quality index (IECQ). (RC)ᵣₑfₑᵣ is selected as an excellent response property value in alliance with corresponding constants (e.g., 1.8 or 2.5) in this method. It is recently found that these constants are not appropriate to normalize indicators for other ion-selective electrodes (ISEs). The present study aimed to report a new and universal route to select good (RC)ᵣₑfₑᵣ values for the normalization without additional constants by only controlling the mean value ([Formula: see text]) being 0.90 < [Formula: see text] < 1.1. The route provided reliable results of both (RC)ᵣₑfₑᵣ for indicator normalization and IECQ values. It has been successfully applied to select the referable values (RC)ᵣₑfₑᵣ of each indicator for the IECQ of three heavy metal (HM) (Co, Ni, and Cr)-ISEs. The second aim of the work is to screen these heavy metal-ion-selective electrodes (HM-ISEs) with highly multiple response properties by using the IECQ. Twenty-four HM-ISEs with the top 3 IECQ values have been recommended. For example, the largest IECQ for three indicators, [Formula: see text], PS, and PRT, which was used as the main indicator (MI), was 1.461 for Co²⁺-ISE, 1.385 for Ni²⁺-ISE, and 1.561 for Cr³⁺-ISE, respectively. The results will be beneficial to meeting the special requirements to monitor/analyze HM ions in different water samples.
Afficher plus [+] Moins [-]COVID-19 and dynamics of environmental awareness, sustainable consumption and social responsibility in Malaysia Texte intégral
2021
Despite a profound evidence of the human unsustainable behaviours’ impact on the environment, stark disparities prevail on this narrative especially in the context of the current epidemiological situation ushered by the COVID-19. The ongoing pandemic is a global public health concern due to its sagacious impacts on environmental sustainability, social responsibility and people’s quality of life. This study primarily focuses on analysing the impact of COVID-19 (COV) on the environmental awareness (EA), sustainable consumption (SC) and social responsibility (SR). Additionally, we aspire to investigate the impact of demographics of generations and religion on the proposed nexus in this study. The data was collected from 700 participants of different age groups and religious backgrounds in Malaysia, and structural equation modelling (SEM) was used to analyse this data and test the hypotheses. The findings indicate that COVID-19 has a significantly positive impact on EA, SC and SR, and the generations and religiosity moderate the relationship between COVID-19 and its impact on sustainable behaviours. This study contributes to analyse the difference in the perception of EA, SC and SR among the people that eventually will stimulate the scientific reasoning among the governments, policymakers and scientists to develop a holistic framework to combat unprecedented event such as COVID-19 and ensure the authentication of sustainable environment and exceptional quality of life. The policymakers in Malaysia may use the findings of this study to inspect the social and environmental aspects of the people during the transformation events.
Afficher plus [+] Moins [-]Multivariate assessment of outflow water quality in highly urbanized creek system: implication of natural and anthropogenic processes Texte intégral
2021
Nutrient source and transport study in tropical creeks adjacent to megacities are sparse on a regional and global scale. High-frequency chemical data collected during 2017–2018 in the Thane creek system, the largest micro-tidal urbanized creek in Asia, were analysed to assess the chemical water quality, with its linkage to different hydrological stages (southwest monsoon, post- and pre-monsoon) and ongoing anthropogenic activities. Cluster analysis indicates typical zonation between creek outflow and nearshore waters with distinctive physicochemical properties. The creek outflow upholds substantial amounts of nutrient and suspended sediment due to turbid water movement from the ephemeral mudflats and anthropogenic dredging. The year-round hyper-turbid condition in the bottom water triggers the addition of disproportionate nutrients (9% dissolved inorganic nitrogen (DIN) and 14% reactive phosphorous (PO₄³⁻) in the outflow region. The DIN and PO₄³⁻ removal up to 10 and 35%, respectively, occurs in the nearshore region; sedimentation, which acts as a sinking interface for nitrogen and phosphorous, also causes shifting in their limiting conditions. The hyper-turbid condition causes removal of dissolved silicate (DSi) by 5% in the entire region. Ammonium (NH₄⁺) is mainly sourced from the sewage in outflow waters and efficiently mineralized. Chemical indexing of water highlights that the bottom water column remained un-supportive to the balanced ecology. The findings of this study have implications for other tropical creek-estuary concerning management strategies against inadequate flushing. The stalled nutrient export affected balance ecology in tropical Thane creek, which need attention in order to accurately understand the impact on adjacent marine environment and to form effective mitigation policies.
Afficher plus [+] Moins [-]Photocatalytic degradation of amoxicillin from aqueous solutions by titanium dioxide nanoparticles loaded on graphene oxide Texte intégral
2021
Balarak, Davoud | Mengelizadeh, Nezamaddin | Rajiv, Periakaruppan | Chandrika, Kethineni
The photocatalytic degradation of amoxicillin (AMX) by titanium dioxide nanoparticles loaded on graphene oxide (GO/TiO₂) was evaluated under UV light. Experimental results showed that key parameters such as initial pH, GO/TiO₂ dosage, UV intensity, and initial AMX concentration had a significant effect on AMX degradation. Compared to the photolysis and adsorption processes, the AMX degradation efficiency was obtained to be more than 99% at conditions including pH of 6, the GO/TiO₂ dosage of 0.4 g/L, the AMX concentration of 50 mg/L, and the intensity of 36 W. Trapping tests showed that all three hydroxyl radical (OH•), superoxide radical (O₂•⁻), and hole (h⁺) were produced in the photocatalytic process; however, h⁺ plays a major role in AMX degradation. Under UV irradiation, GO/TiO₂ showed excellent stability and recyclability for 4 consecutive reaction cycles. The analysis of total organic carbon (TOC) suggested that AMX could be well degraded into CO₂ and H₂O. The formation of NH₄⁺, NO₃⁻, and SO₄²⁻ as a result of AMX degradation confirmed the good mineralization of AMX in the GO/TiO₂/UV process. The toxicity of the inlet and outlet samples of the process has been investigated by cultivation of Escherichia coli and Streptococcus faecalis, and the results showed that the condition is suitable for the growth of organisms. The photocatalytic degradation mechanism was proposed based on trapping and comparative tests. Based on the results, the GO/TiO₂/UV process can be considered as a promising technique for AMX degradation due to photocatalyst stability, high mineralization efficiency, and effluent low toxicity.
Afficher plus [+] Moins [-]Morin protects against acrylamide-induced neurotoxicity in rats: an investigation into different signal pathways Texte intégral
2021
Gur, Cihan | Kandemir, Fatih Mehmet | Darendelioglu, Ekrem | Caglayan, Cuneyt | Kucukler, Sefa | Kandemir, Ozge | Ileriturk, Mustafa
The presented study investigates the effects of morin against toxicity induced by acrylamide (ACR) in the brains of Sprague Dawley rats. In this study, neurotoxicity was induced by orally administering 38.27 mg/kg/b.w ACR to rats through gastric gavage for 10 days. Morin was administered at the same time and at different doses (50 and 100 mg/kg/b.w) with ACR. Biochemical and Western blot analyses showed that ACR increased malondialdehyde (MDA), p38α mitogen-activated protein kinase (p38α MAPK), nuclear factor kappa-B (NF-κB), tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2), p53, caspase-3, bcl-2 associated X protein (Bax), Beclin-1, light chain 3A (LC3A), and light chain 3B (LC3B) levels and decreased those of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH), b-cell lymphoma-2 (Bcl-2), mammalian target of rapamycin (mTOR), phosphoinositide 3-kinase (PI3K), and protein kinase B (Akt) in brain tissue and therefore induced neurotoxicity by causing oxidative stress, inflammation, apoptosis, and autophagy. On the other hand, it was determined that morin positively affected the levels of these markers by displaying antioxidant, anti-inflammatory, anti-apoptotic, and anti-autophagic properties and had a protective effect on ACR-induced neurotoxicity. As a result, morin is an effective substance against brain damage caused by ACR, yet further studies are needed to use it effectively.
Afficher plus [+] Moins [-]Effect of carbon source on nitrous oxide emission characteristics and sludge properties during anoxic/aerobic wastewater treatment process Texte intégral
2021
Yan, Xu | Yang, Jie | Guo, Dongli | Ma, Jiahui | Su, Xianfa | Sun, Jianhui
Carbon sources are an important parameter in wastewater treatment processes and are closely related to treatment efficiency and nitrous oxide (N₂O) emissions. In this study, three parallel sequencing batch reactors (SBRs) were processed with acetic acid, propionic acid, and a 1:1 mixture of both acids (calculated in COD) to study the effect of carbon sources on N₂O generation and sludge properties (including intracellular polymer content, extracellular polymeric substance (EPS) composition, particle size distribution, settleability, and microbial community structure). The results showed that the highest COD, NH₄⁺-N, and TP removal efficiencies (92.2%, 100%, and 82.3%, respectively) were achieved by the reactor with mixed acid as the carbon source, whereas the reactor using acetic acid had the highest TN removal rate (82.6%) and the lowest N₂O–N conversion rate (1.4%, based on TN removal). The reactor with the carbon source of mixed acid produced the highest polyhydroxyalkanoate (PHA) content, which led to an increase in N₂O generation from the aerobic denitrification pathway. The SBR with mixed acid carbon source also had the highest concentration of EPS, which resulted in the largest particle size and the lowest settleability of sludge flocs among the SBRs. Microbial analysis results revealed that the difference in carbon sources resulted in a variation in the microbial community as well as in the relative abundances of functional microbes involved in biological nitrogen removal processes. The mixed acid promoted the development of ammonia-oxidizing bacteria (AOB), which conducted the primary N₂O generation pathway of aerobic denitrification bioreactions. The carbon source of acetic acid promoted the growth of denitrifying bacteria (DNB), which led to the highest TN removal rate. This study provides a comprehensive understanding of the effects of carbon sources on N₂O generation and sludge properties for WWTPs.
Afficher plus [+] Moins [-]Research on the site selection of watershed public facilities as multi-use detention basin: an environmental efficiency perspective Texte intégral
2021
Chang, Hsueh-Sheng | Man, Chun-Yin | Su, Qingmu
With the climate change and the acceleration of urbanization, urban flood disaster is becoming increasingly frequent, leading to more severe impact than in the past. The traditional disaster alleviation strategies have gradually expanded to non-engineering disaster reduction strategies. As urban public property, public facility is more available than private land, making it the preferred strategy of site selection for urban land flood diversion. However, due to the limited government finance, how to select public facilities as the multi-use detention basin to maximize the disaster reduction and external benefits is an issue that needs to be considered before planning and decision-making. This study builds an operable decision model of site selection of urban public facilities as multi-use detention basin from the perspective of environmental efficiency. The decision model analyzes the expected costs and benefits of the multi-use detention basin based on data envelopment analysis (DEA) and cross-efficiency analysis, so as to establish the optimal combination of alternative schemes of site selection. It further compares with the traditional detention basin considering only disaster reduction efficiency to summarize how to improve the strategy of selecting multi-use detention basin site within the watershed in the future. This paper uses the watershed of Dajiaxi as a case study, and finds that (I) there is a certain trade-off relationship between the optimized schemes established from the perspective of environmental efficiency and disaster reduction efficiency evaluation. The scheme with the highest disaster reduction efficiency does not necessarily increase the external benefit significantly; (II) for the inefficient schemes, the difference between the site selection schemes and the ideal efficiency value can be measured through slack variable analysis.
Afficher plus [+] Moins [-]Are the Endogenous Levels of Divalent Heavy Metals Responsible for the Oxidative Stress Response on Freshwater Phytoplankton Communities? Texte intégral
2021
Nájera-Martínez, Minerva | Pérez-Cruz, Anabel | Dzul-Caamal, Ricardo | Vega-López, Armando
Some evidences about the toxicity of heavy metals on phytoplankton communities have been documented; notwithstanding, a little of information about the toxic effects elicited by these toxicants prevails. The study aim was to evaluate the relationships between heavy metals on freshwater phytoplankton communities (FWPC) with biomarkers of the oxidative stress response. Biomarkers of oxidative damage (TBARS, RC=O), antioxidant defenses (SOD, CAT, and GPx), and burdens of Cu, Fe, Mn, Pb, and Zn were measured on FWPC from four artificial lakes and in one natural lake. Relationships with metals and with pH and redox, using principal component analysis (PCA) and redundancy analysis (RDA), were assessed. RDA showed that TBARS and CAT were related to the burden of Fe and with the water levels of Cu in artificial lakes at the beginning of the rainy season. SOD and GPx activities were influenced by loads of Cu, Pb, Mn, and Zn and by the pH and redox from artificial lakes between the months of February and April. By PCA, it was found that oxidation of proteins was similar in the FWPC from ancient lake and semiartificial lake; however, it was not related to the burdens of metals neither to the concentration of heavy metals in the water. On the FWPC from the natural lake, none of the biomarkers under study was related to the burdens or water concentration of heavy metals. Endogenous levels of heavy metals are responsible for the oxidative stress response on the FWPC, particularly, noticeable in the phytoplankton communities from artificial lakes.
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