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Resultados 3061-3070 de 6,535
Characterization and Mechanisms of a New Carbonaceous Adsorbent Based on Black Liquor Loaded with Iron Oxide for Removal of Tripolyphosphate Ions
2020
Sari, Ajeng Arum | Akhmad, Rifahny Intan Satria | Asmara, Adelia Anju | Arutanti, Osi | Hadibarata, Tony | Andreas, | Yasin, Hasbi | Saefumillah, Asep | Yuniarto, Adhi
The impregnation process has successfully prepared a novel composite of iron oxide/carbon from black liquor (CA-BL/Fe) as an adsorbent for the removal of tripolyphosphate ions. Black liquor is a secondary product of the bioethanol pre-treatment process. X-ray diffraction results showed that the main iron oxide species present in the CA-BL/Fe was goethite (α-FeOOH). Interestingly, the specific surface area of CA-BL/Fe was 504 m²/g higher than that of commercial activated carbon of 356 m²/g. The adsorption performance showed that tripolyphosphate ion removal efficiency increased by increasing the adsorbent dosage, pH, and contact time. At the same time, it decreased with an increase in the initial concentration of tripolyphosphate. By controlling the environment pH value, the optimum removal efficiency of tripolyphosphate ions with CA-BL/Fe was 96.87%, with the adsorption capacity of 1.5922 mg/g for 1 h measurement. In this study, the dominant mechanisms of tripolyphosphate adsorption are electrostatic attraction and ion exchange. The result of this study is expected to be the basis for further promising adsorbent material for tripolyphosphate ion.
Mostrar más [+] Menos [-]Degradation of recalcitrant organic matter in SAARB leachate by a combined process of coagulation and catalytic ozonation
2020
Xiang, Yan | Chen, Yaping | Luo, Siqiang | Zou, Junliang | Zhang, Aiping
A combined coagulation and γ-Al₂O₃ catalytic ozonation process was used to treat semi-aerobic aged refuse biofilter (SAARB) effluent from treating mature landfill leachate. First, the coagulant providing the best pretreatment performance was selected. Then, the coagulated SAARB leachate was further treated in an optimized γ-Al₂O₃-catalyzed ozonation process. Characteristics of the γ-Al₂O₃-catalyzed ozonation process were determined, and a reaction mechanism was proposed. FeCl₃ provided the best treatment efficiency (chemical oxygen demand (COD) removal of 65.8%, absorbance at 254 nm (UV₂₅₄) removal of 68.55%, and color number (CN) removal of 79.4%). Under optimized O₃ dosage (18.92 mg/min) and γ-Al₂O₃ dosage (10 g/L), efficiencies of removing COD, UV₂₅₄, and CN were 54.3%, 82.9%, and 95.9%, respectively, at 30 min. In addition, spectral analysis indicated that fulvic-like substances in ultraviolet and visible regions were effectively degraded in the γ-Al₂O₃-O₃ process and some smaller organic products were produced. Characterization of γ-Al₂O₃ showed that γ-Al₂O₃ was relative stable; its morphology and constituent elements did not change much after reaction. In addition, ozonation capacity was enhanced by heterogeneous catalytic effects of γ-Al₂O₃. The combined coagulation and γ-Al₂O₃ catalytic ozonation process was proven to be an efficient treatment method for removing bio-refractory organic matter contained in SAARB leachate.
Mostrar más [+] Menos [-]Pyrolysis characteristics of cathode from spent lithium-ion batteries using advanced TG-FTIR-GC/MS analysis
2020
Yu, Shaoqi | Xiong, Jingjing | Wu, Daidai | Lü, Xiaoshu | Yao, Zhitong | Xu, Shaodan | Tang, Junhong
Thermal treatment offers an alternative method for the separation of Al foil and cathode materials during spent lithium-ion batteries (LIBs) recycling. In this work, the pyrolysis behavior of cathode from spent LIBs was investigated using advanced thermogravimetric Fourier transformed infrared spectroscopy coupled with gas chromatography-mass spectrometer (TG-FTIR-GC/MS) method. The fate of fluorine present in spent batteries was probed as well. TG analysis showed that the cathode decomposition displayed a three-stage process. The temperatures of maximum mass loss rate were located at 470 °C and 599 °C, respectively. FTIR analysis revealed that the release of CO₂ increased as the temperature rose from 195 to 928 °C. However, the evolution of H₂O showed a decreasing trend when the temperature increased to above 599 °C. The release of fluoride derivatives also exhibited a decreasing trend, and they were not detected after temperatures increasing to above 470 °C. GC-MS analysis indicated that the release of H₂O and CO displayed a similar trend, with larger releasing intensity at the first two stages. The evolution of 1,4-difluorobenzene and 1,3,5-trifluorobenzene also displayed a similar trend—larger releasing intensity at the first two stages. However, the release of CO₂ showed a different trend, with the largest release intensity at the third stage, as did the release of 1,2,4-trifluorobenzene, with the release mainly focused at the temperature of 300–400 °C. The release intensities of 1,2,4-trifluorobenzene and 1,3,5-trifluorobenzene were comparable, although smaller than that of 1,4-difluorobenzene. This study will offer practical support for the large-scale recycling of spent LIBs.
Mostrar más [+] Menos [-]Carbon dioxide emissions from transport and anemia influence on under-five mortality in Benin
2020
Sokadjo, Yves Morel | Atchadé, Mintodê Nicodème | Kossou, Hortense Désirée
This work is the first study about the joint effect (influence) of carbon dioxide emissions (CO₂) from transport and anemia influence on under-five mortality in the Republic of Benin. We focused on that interaction effect and provide scientific pieces of evidence through multiple linear and multinomial regression models. Therefore, the World Bank yearly data about Benin has been used. Time series analysis and co-integration checking were done to deepen the study. The interaction of anemia and CO₂ emissions from transport influences positively under-five mortality (U5M) rate (p = 0.00). Findings reveal that when CO₂ emissions from transport and anemia increase of 1 unit in a given year, Benin is likely to have 10 deaths over 1000 live births higher on the under-five mortality rate the following year.
Mostrar más [+] Menos [-]Is there a waste Kuznets curve for OECD? Some evidence from panel analysis
2020
Yılmaz, Fırat
We empirically investigated the existence of a Kuznets curve for OECD area in terms of municipal solid waste generation by utilizing a panel data covering the 2002–2017 period. Results from GMM and between estimators conclude that an inverted U-shaped Kuznets relationship holds for OECD countries, but only in relative terms. Results show that consumption expenditure is one of the main drivers of waste generation. Country-based estimations of random coefficient approach state that 8 out of 16 high-income countries and only 2 out of low-income countries have achieved decoupling the waste generation from consumption expenditures. Some policy implications are recommended.
Mostrar más [+] Menos [-]Influence of different preparation methods on the activity of Ce and Mo co-doped ZSM-5 catalysts for the selective catalytic reduction of NOx by NH3
2020
Li, Zhifang | Yang, Jian | Zhou, Yadong | Cui, Jinxing | Ma, Yuanyuan | Geng, Cui | Kang Yan, | Liu, Jiayin | Yang, Changlong
The Ce-doped different MoO₃ [conventional molybdenum oxide (con-MoO₃) or nano molybdenum oxide (nano-MoO₃) and synthetic molybdenum oxide (syn-MoO₃)] modification of ZSM-5 catalyst synthesized by different preparation methods (the combination of grinding and ion-exchange method and the combination of impregnation and ion-exchange method) was studied on selective catalytic reduction (SCR) of NOₓ with NH₃. The results demonstrated that the SCR performance of the prepared Ce-doped syn-MoO₃ modification of ZSM-5 catalyst [Ce(0.9%)-syn-MoO₃(6%)/ZSM-5] by the combination of impregnation and ion-exchange method was better than Ce-doped con-MoO₃ modification of ZSM-5 [Ce(0.9%)-con-MoO₃(6%)/ZSM-5] and Ce-doped nano-MoO₃ modification of ZSM-5 [Ce(0.9%)-nano-MoO₃(6%)/ZSM-5] via the combination of grinding and ion-exchange method, especially when the temperature window is 200–350 °C. That is because it is easy to form Mo-O-Al by the smaller sized MoO₃ more easily interacting well with Brønsted acid under calcining temperature, which results in the decrease of Brønsted acid sites in the catalyst. Combing with the binding energy of Mo for all the catalysts, the combination of Mo and Al (Mo-O-Al) altered the chemical environment around the Mo species. Furthermore, Ce(0.9%)-syn-MoO₃(6%)/ZSM-5 exhibited excellent sulfur resistance.
Mostrar más [+] Menos [-]Efficacy of Andrographis paniculata supplements induce a non-specific immune system against the pathogenicity of Aeromonas hydrophila infection in Indian major carp (Labeo rohita)
2020
Palanikani, Radhakrishnan | Chanthini, Kanagaraj Muthu-Pandian | Soranam, Ramaiah | Thanigaivel, Annamalai | Karthi, Sengodan | Senthil-Nathan, Sengottayan | Murugesan, Arunachalam Ganesan
Aeromonas hydrophila, an opportunistic fish pathogen, which causes several major diseases including skin ulcer and haemorrhagic septicemia, contributes considerably to the lethality in aquaculture. Chemical and antibiotic treatment employed against A. hydrophila for disease management are expensive and consequently prompted the advent of drug resistance among the pathogens. To overcome these draw backs, alternative aquatic disease control methods using conventional plant-based medicines are focussed. Our present study aimed to augment the fish non-specific immune system with the implementation of methanolic crude extracts of Andrographis paniculata to Labeo rohita, for evaluating their efficacy against A. hydrophila. Histology of major organs of A. hydrophila-infected fish such as the gills and liver displayed severe tissue damage. A. paniculata extracts exhibited the strong antibacterial activity against A. hydrophila even at lower concentrations (50 μl). The extracts also altered the haematological profile of treated infected fishes by increasing the levels of haemoglobin and total erythrocyte-leucocyte counts, along with the phagocytic index. The extracts also had a significant impact on modifying the anatomy and swimming pattern of infected fish, post treatment with the extracts. Also, A. paniculata treated infected fishes in all the plant extract administration methods, viz. injection, oral feeding and diffusion, and reduced the cumulative mortality rate to less than 30%. Even lower concentrations of A. paniculata extracts (50 μl) resulted in maximum relative percentage survival of treated fishes. Therefore, our findings suggest that A. paniculata was effective against A. hydrophila infection in aquaculture, thereby maintaining a healthy status of these fishes in aquaculture.
Mostrar más [+] Menos [-]Applying modified biochar with nZVI/nFe3O4 to immobilize Pb in contaminated soil
2020
Li, Peirou | Yu, Jiang | Huangfu, Zhuoxi | Chang, Jiahua | Zhong, Chengwei | Ding, Ping
Lead (Pb) pollution in soil has become one of the most serious environmental problems, and it is more urgent in areas where acid rain is prevalent. Curing agents to solidify heavy metals in soil are efficiently applied to remediate Pb-contaminated soil. In this study, we prepared biochar, biochar loaded with nano-zero-valent iron (BC-nZVI), and biochar loaded with nano-ferroferric oxide (BC-nFe₃O₄), and investigated the Pb-immobilizing efficiency in contaminated soil in the condition of acid rain by them. The results showed that 8 g/kg is the best added dosage of curing agents for immobilizing Pb, which of the immobilizing efficiency of Pb were 19% (biochar), 42% (BC-nZVI), and 23% (BC-nFe₃O₄), respectively. Besides, the curing agents had positive effects on immobilizing Pb under acid rain condition, which could significantly reduce the content of acid extractable Pb, especially BC-nZVI (1.5%). And the immobilization efficiency of modified biochar was better than biochar, especially BC-nZVI (66%). BC-nZVI showed a more ideal effect on decreasing the leaching amount of Pb in the condition of acid rain. The results highlighted that biochar-loaded nano-iron-based materials, especially BC-nZVI, was promising and environmentally friendly materials for remediating Pb-contaminated soils, which provided scientific reference and theoretical basis for the treatment of Pb-contaminated soils around industrial sites particularly in acid rain area.
Mostrar más [+] Menos [-]Mathematical modeling for green supply chain considering product recovery capacity and uncertainty for demand
2020
Mehrbakhsh, Sanaz | Ghezavati, Vahidreza
Competition in today’s market is the most important concern of companies and producers in free markets. Buyers are also looking for higher quality and lower prices. Manufacturers should, therefore, reduce production costs and increase budgets for research and product development. On the other hand, the limitation of mineral resources in each country and in the world in general is a very important factor for increasing the price of raw materials which increases the cost of production of a product. In this study, a green aspect of decision-making, concurrent modeling for inventory-routing, and application of maximum entropy (ME) method for overcoming uncertainties of demands are applied to optimize the usage of raw materials and returning of defective products to the production cycle in a closed-looped supply chain under multi-period planning horizon. Also, dynamic modeling is used to balance the inventory level in all stages of the network that leads to optimum usage of the raw materials. For this purpose, the first objective function reduces production, transportation-routing, and inventory costs, and the second objective reduces greenhouse gas emissions through all levels of the network. Finally, this model is solved by using the exact solution method with the help of Gams software as well as the non-dominated sorting genetic algorithm II (NSGAII) and multi-objective particle swarm optimization (MOPSO) algorithm. Sensitivity analysis has been performed on failure rates, greenhouse gas emissions during recycling and production, and the optimistic-pessimistic coefficient of the ME solution method. Solution methods have been compared using several criteria, and the NSGAII method has finally obtained the best result. The results show that the manager should pay more costs in order to prevent backorder demands. Also, collecting the more defective products leads to increasing production amount since the collective products can return to the production line. Finally, it is required for the managers to control products’ failure rate to optimize capacity usage in the model.
Mostrar más [+] Menos [-]Effect of temperature on microcystin-LR removal and lysis activity on Microcystis aeruginosa (cyanobacteria) by an indigenous bacterium belonging to the genus Achromobacter
2020
Crettaz-Minaglia, Melina | Fallico, Maximiliano | Aranda, Oswaldo | Juárez, Iván | Pezzoni, Magdalena | Costa, Cristina | Andrinolo, Dario | Giannuzzi, Leda
Microcystis is a frequent cyanobacterium bloom-forming with cosmopolitan distribution which can produce a hepatotoxin group called microcystins (MCs). These MCs are resistant to the traditional processes employed in the water treatment plants and they are often detected after conventional treatments. Because of this, the bio-removal studies have obtained a great interest in the last decades. In this work, a bacterial strain namely LG1 with the ability to remove microcystin-LR (MC-LR) under laboratory conditions was isolated from Rio de la Plata River and it was identified as Achromobacter spp. This ubiquitous bacterium was able to remove 79.5% MC-LR in 7 days with average removal time of 3.33 ± 0.08, 3.06 ± 0.05, and 2.77 ± 0.05 days at 28, 32, and 36 ± 1 °C, being higher at high temperature (36 °C) with an activation energy = 16.79 ± 1.99 kJ mol⁻¹. LG1 grew better at higher temperature (from 28 to 36 ± 1 °C) increasing the specific growth rate (μ) and reducing 2-fold the lag phase duration (LPD) without significant differences (p > 0.05) between maximum population density (MPD). In addition, LG1 showed a lysis activity on two M. aeruginosa native strains in 7 days measured as chlorophyll a (Chl-a) concentration. The lysis activity increased around 2-fold when increasing the temperature from 28 to 36 ± 1 °C. This is the first report of an indigenous bacterium belonging to the genus Achromobacter spp. isolated from the Rio de la Plata River with the capacity to remove MC-LR and lysis activity on M. aeruginosa.
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