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A comparative life cycle assessment (LCA) of concrete and steel-prefabricated prefinished volumetric construction structures in Malaysia Texto completo
2020
Balasbaneh, Ali Tighnavard | Ramli, Mohd Zamri
In recent years, off-site volumetric construction has been promoted as a viable strategy for improving the sustainability of the construction industry. Most prefabricated prefinished volumetric construction (PPVC) structures are composed of either steel or concrete; thus, it is imperative to carry out life cycle assessments (LCAs) for both types of structures. PPVC is a method by which free-standing volumetric modules—complete with finishes for walls, floors, and ceilings—are prefabricated and then transferred and erected on-site. Although many studies have examined these structures, few have combined economic and environmental life cycle analyses, particularly for prefinished volumetric construction buildings. The purpose of this study is to utilize LCA and life cycle cost (LCC) methods to compare the environmental impacts and costs of steel and concrete PPVCs “from cradle to grave.” The results show that steel necessitates higher electricity usage than concrete in all environmental categories, while concrete has a higher emission rate. Steel outperforms concrete by approximately 37% in non-renewable energy measures, 38% in respiratory inorganics, 43% in land occupation, and 40% in mineral extraction. Concrete, on the other hand, performs 54% better on average in terms of measures adopted for greenhouse gas (GHG) emissions. Steel incurs a higher cost in the construction stage but is ultimately the more economical choice, costing 4% less than concrete PPVC owing to the recovery, recycling, and reuse of materials. In general, steel PPVC exhibits better performance, both in terms of cost and environmental factors (excluding GHG emissions). This study endeavors to improve the implementation and general understanding of PPVC.
Mostrar más [+] Menos [-]The quantification of bisphenols and their analogues in wastewaters and surface water by an improved solid-phase extraction gas chromatography/mass spectrometry method Texto completo
2020
Caban, Magda | Stepnowski, Piotr
The study focused on the application of GC in the quantitative analysis of bisphenols and their analogues (12 analytes), and the improvement of solid-phase extraction for the whole water analysis of complex water samples. The role of silylation in the qualitative and quantitative analysis of bisphenols was investigated. Partial degradation occurred for selected targets during hot injection with the presence of a silylation agent. A PSA (primary and secondary amines) sorbent placed on the top of the solid-phase extraction (SPE) column sorbent was found to be a matrix component trap, mostly for humic acids. The whole water analysis was performed by washing the filters with methanol and recycling the extract to the sample. The validation of SPE-GC/MS(SIM) gave limits of detection of 1–50 ng/L for ten target bisphenols with a method recovery of between 87 and 133%. The application of the method was tested by the analysis of wastewater sampled from three wastewater treatment plants located in Poland, and municipal surface waters. The only analytes found were BPA and BPS, within the range of 16–1465 ng/L and < MDL-1249 ng/L in wastewater, and 170–3113 ng/L and < MDL-1584 ng/L in surface water, respectively.
Mostrar más [+] Menos [-]Life cycle assessment of most widely adopted solar photovoltaic energy technologies by mid-point and end-point indicators of ReCiPe method Texto completo
2020
Rashedi, A. | Khanam, Taslima
The present article focuses on a cradle-to-grave life cycle assessment (LCA) of the most widely adopted solar photovoltaic power generation technologies, viz., mono-crystalline silicon (mono-Si), multi-crystalline silicon (multi-Si), amorphous silicon (a-Si) and cadmium telluride (CdTe) energy technologies, based on ReCiPe life cycle impact assessment method. LCA is the most powerful environmental impact assessment tool from a product perspective and ReCiPe is one of the most advanced LCA methodologies with the broadest set of mid-point impact categories. More importantly, ReCiPe combines the strengths of both mid-point-based life cycle impact assessment approach of CML-IA, and end-point-based approach of Eco-indicator 99 methods. Accordingly, the LCA results of all four solar PV technologies have been evaluated and compared based on 18 mid-point impact indicators (viz., climate change, ozone depletion, terrestrial acidification, freshwater eutrophication, marine eutrophication, human toxicity, photochemical oxidant formation, particulate matter formation, terrestrial ecotoxicity, freshwater ecotoxicity, marine ecotoxicity, ionising radiation, agricultural land occupation, urban land occupation, natural land transformation, water depletion, metal depletion and fossil depletion), 3 end-point/damage indicators (viz., human health, ecosystems and cost increases in resource extraction) and a unified single score. The overall study has been conducted based on hierarchist perspective and according to the relevant ISO standards. Final results show that the CdTe thin-film solar plant carries the least environmental life cycle impact within the four PV technologies, sequentially followed by multi-Si, a-Si and mono-Si technology.
Mostrar más [+] Menos [-]Three-dimensional cubic ordered mesoporous carbon with chitosan for capacitive deionization disinfection of water Texto completo
2020
Cao, Cuihui | Wu, Xiaofeng | Zheng, Yuming | Chen, Yunfa
Three-dimensional cubic ordered mesoporous carbon with chitosan (Ia3d-CS), which was synthesized via exothermic reaction between liquid potassium and carbon monoxide gas, was coated on the active carbon (AC) electrode as a capacitive deionization (CDI) disinfection electrode. The results showed that Ia3d-CS-2 as CDI electrode exhibited the quick ion diffusion and strong charge transfer performance, due to the three-dimensional pore structure and specific surface area. The electrode of Ia3d-CS-2 displayed a specific capacity of 191.22 F/g at a scan rate of 100 mV·s⁻¹ in 0.5 M NaCl aqueous solution. In a CDI recycling system, Ia3d-CS-x electrode showed good cyclic stability, and the electrosorption capacity of Ia3d-CS-2 electrode can achieve 1.31 mg/g at 1.2 V in 100 mg/l NaCl aqueous solutions. Subsequently, Ia3d-CS-2 electrode had an excellent disinfection efficiency of killing about 99.99% Escherichia coli within 30 min during the CDI process at applied 1.2 V. Considering those excellent properties of the fabricated Ia3d-CS-x electrode, which should be a better candidate for high-performance deionization application.
Mostrar más [+] Menos [-]Metallurgical processes unveil the unexplored “sleeping mines” e- waste: a review Texto completo
2020
Thakur, Pooja | Kumar, Sudhir
The aim of this review paper is to critically analyze the existing studies on waste electric and electronic equipment (WEEE), which is one of the most increasing solid waste streams. This complex solid waste stream has pushed many scientific communities to develop novel technologies with minimum ecological disturbance. Noteworthy amount of valuable metals makes e-waste to a core of “urban mining”; therefore, it warrants special attention. Present study is focused on all the basic conceptual knowledge of WEEE ranging from compositional analysis, global statistics of e-waste generation, and metallurgical processes applied for metals extraction from e-waste. This review critically analyses the existing studies to emphasize on the heterogeneity nature of e-waste, which has not been focused much in any of the existing review articles. Comprehensive analysis of conventional approaches such as pyrometallurgy and hydrometallurgy reveals that high costs and secondary pollution possibilities limit the industrial feasibilities of these processes. Therefore biohydrometallurgy, a green technology, has been attracting researchers to focus on this novel technique to implement it for metal extraction from WEEE.
Mostrar más [+] Menos [-]Solubility and reactivity of surfactant-enhanced alkaline hydrolysis of organophosphorus pesticide DNAPL Texto completo
2020
Muff, Jens | MacKinnon, Leah | Durant, Neal D. | Bennedsen, Lars Frausing | Rügge, Kirsten | Bondgaard, Morten | Pennell, Kurt D.
The study presented in this paper evaluated the effectiveness of surfactants in enhancing mass removal of organophosphorus pesticides (OPPs) from soil under highly alkaline conditions and potential for enhancing in situ alkaline hydrolysis for treatment of OPPs, particularly parathion (EP3) and methyl parathion (MP3). In control and surfactant experiments, hydrolysis products EP2 acid, MP2 acid, and PNP were formed in non-stoichiometric amounts indicating instability of these compounds. MP3 and malathion were found to have faster hydrolysis rates than EP3 under the conditions studied. All surfactants evaluated increased solubility of OPPs under alkaline conditions with four nonionic alcohol ethoxylate products providing the greater affect over the polyglucosides, sulfonate, and propionate surfactants evaluated. The alcohol ethoxylates were shown to provide substantial mass removal of OPPs from soil. Hydrolysis rates were typically slower in the presence of surfactant, despite the relatively higher aqueous concentrations of OPPs; this was likely due to micellar solubilization of the OPPs which were therefore less accessible for hydrolysis. The results of this study support the use of surfactants for contaminant mass removal from soil, particularly under alkaline conditions, and may have implications for use of some surfactants in combination with other technologies for treatment of OPPs.
Mostrar más [+] Menos [-]An improved gray Bernoulli model for estimating the relationship between economic growth and pollution emissions Texto completo
2020
Li, Qin | Wang, Zheng-Xin | Zhang, Xiang-Yu
The environmental Kuznets curve (EKC) hypothesis is used to describe the relationship between economic development and environmental pollution. In this paper, an EKC-estimating method based on an improved nonlinear gray Bernoulli model (NGBM) is proposed from the perspective of gray system modeling. First, a non-equigap NGBM is established taking the GDP per capita and pollutant emission as the input and output of the gray system, respectively. Then, a particle swarm optimization algorithm is used to find the parameters in the nonlinear model. Finally, the EKC is validated by applying it to the per capita emission of wastewater, SO₂, CO₂, and soot in China. The results show that the new method proposed in this paper optimizes the exponent of the NGBM which allows it to describe the trends in the different morphological data very well, resulting in a higher fitting accuracy. China’s per capita emission of wastewater, SO₂, CO₂, and soot show trends corresponding to monotonically increasing, inverted U-shaped, S-shaped, and N-shaped changes, respectively.
Mostrar más [+] Menos [-]Oxidative stress and mitochondrial dysfunction in organophosphate pesticide-induced neurotoxicity and its amelioration: a review Texto completo
2020
Farkhondeh, Tahereh | Mehrpour, Omid | Forouzanfar, Fatemeh | Roshanravan, Babak | Samarghandian, Saeed
Organophosphorus pesticides (OPs) are widely used for controlling pests worldwide. The inhibitory effects of these pesticides on acetylcholinesterase lead to neurotoxic damages. The oxidative stress is responsible for several neurological diseases, including Parkinson’s disease, seizure, depression, and Alzheimer’s disease. Strong evidence suggests that dysfunction of mitochondria and oxidative stress are involved in neurological diseases. OPs can disturb the function of mitochondria by inducing oxidative stress. In the present study, we tried to highlight the role of dysfunction of mitochondria and the induction of oxidative stress in the neurotoxicity induced by OPs. Additionally, the amelioration of OP-induced oxidative damage and mitochondrial dysfunctional through the chemical and natural antioxidants have been discussed.
Mostrar más [+] Menos [-]Effect of plant hedgerows on agricultural non-point source pollution: a meta-analysis Texto completo
2020
Zheng, Yonglin | Wang, Haiyan | Qin, Qianqian | Wang, Yige
Eutrophication has been a critical environmental issue due to soil nitrogen (N) and phosphorus (P) loss in runoff from agricultural lands. Plant hedgerow is an important measure to prevent soil erosion and reduce agricultural non-point source pollution (NPSP). In the present study, we searched 3683 research papers on plant hedgerows published from 1980 to March 2020. After screening, we used 53 effective papers on plant hedgerows for the meta-analysis by using Stata 15.1. The results showed that plant hedgerows significantly increased soil organic matter (SOM) (standardized mean difference (SMD) = 1.46; 95% confidence interval (CI) = 1.12–1.80 > 0), total N (TN) (SMD = 1.33; 95% CI 0.98–1.68 > 0), total P (SMD = 0.73; 95% CI 0.26–1.20 > 0), alkali N (SMD = 0.86; 95% CI 0.52–1.21 > 0), available P (SMD = 1.28; 95% CI 0.75–1.81 > 0) and readily available potassium (K) (SMD = 1.20; 95% CI 0.75–1.65 > 0) concentrations but exhibited no significant effects on soil total K concentration (SMD = 0.17; 95% CI − 0.13–0.47 < 0). Plant hedgerows showed a greater effect on SOM increase than soil N, P, and K, and soil TN increase than the available state, but the opposite trend was observed for P and K. This meta-analysis can clarify the influence of plant hedgerows on soil nutrients and provide ideas for the prevention and control of agricultural NPSP.
Mostrar más [+] Menos [-]Novel reduced graphene oxide/ZnBi2O4 hybrid photocatalyst for visible light degradation of 2,4-dichlorophenoxyacetic acid Texto completo
2020
Tho, Nguyen Thi Mai | Khanh, Dang Nguyen Nha | Thang, Nguyen Quoc | Lee, Yong-Ill | Phuong, Nguyen Thi Kim
A new highly efficient rGO/ZnBi₂O₄ hybrid catalyst has been successfully synthesized through oxidation-reduction and co-precipitation methods, followed by heating at 450 °C. The obtained rGO/ZnBi₂O₄ catalyst was characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The catalytic activity of rGO/ZnBi₂O₄ under visible light irradiation was tested using 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution. The rGO/ZnBi₂O₄ hybrid catalyst containing 2% rGO (2.0rGO/ZnBi₂O₄) showed the best catalytic performance. More than 90% of 2,4-D in a 30 mg/L solution was degraded after 120 min of visible light irradiation using 2.0rGO/ZnBi₂O₄ at 1.0 g/L concentration. Moreover, the 2.0rGO/ZnBi₂O₄ catalyst showed excellent stability over four consecutive cycles, with no significant changes in the photocatalytic degradation rate. This study demonstrated that rGO/ZnBi₂O₄ may be a promising, low-cost, and green photocatalyst for environmental remediation applications.
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