Catalytic activity of spinel ferrite in breaking down toxic dye materials are promising due to their uniqueness. In this study, aluminum-doped copper zinc ferrite, Cu0.4Zn0.6-xAlxFe2O4 (x = 0.0, 0.2, 0.4, 0.6), a catalyst for toxic dye degradation is synthesized through chemical co-precipitation route. The formation of the spinel ferrite catalyst is initially confirmed by Fourier transform infrared spectra, which shows the frequency of metal-oxygen bond vibration at 539 and 427 cm−1 attributed to the tetrahedral and octahedral sites respectively. Higher intensity sharp peak of X-ray diffraction for (311) plane is the evidence for the phase purity and the formation of spinel ferrite. The crystallite size is found to decrease with the increase of Al3+ ion. The surface structure of the obtained particles is investigated using a scanning electron microscope. Analyses of the material's magnetic characteristics using a vibrating sample magnetometer (VSM) revealed that it is, in fact, a soft magnet, as evidenced by the loop of its hysteresis, which is narrow. The catalytic degradation of methylene blue dye under the mechanism of the photo-Fenton process is studied with the obtained spinel ferrites and the result is found to be as high as 96.5%. The process follows pseudo-second order kinetics and the Langmuir isotherm. 相似文献
Environmental and Ecological Statistics - Optimizing sustainable renewable energy portfolios is one of the most complicated decision making problems in energy policy planning. This process involves... 相似文献
The toxicity of the water-soluble fraction (WSF) of four fuels (leaded gasoline, unleaded gasoline, diesel, Jet A-1) to Metamysidopsis insularis, an indigenous tropical mysid species was determined. Approximately 10 000 barrels (bbl) of fuel are consumed daily in Trinidad and Tobago, and about 50 000 bbl are exported. Accidental discharges at points of transfer as well as from inadequate storage facilities, can pose a significant contamination risk to the environment. Organisms were assayed with the WSF under both UV and fluorescent lights. The WSF was prepared using different fuel/seawater (v/v) mixtures. It was found that organisms exposed to diesel, Jet A-1 and unleaded gasoline showed similar toxicological responses under both light regimes, and were more toxic than the leaded gasoline. The results also showed that none of these fuels show photo-induced toxicity. The WSF of the 0.1% mixtures of unleaded gasoline, diesel and Jet A-1 were acutely toxic to M. insularis. However, for the leaded gasoline, only the 0.5% mixture was acutely toxic. The high toxicity of these fuels may be due to the presence of light, more soluble fractions. It is therefore likely that these fuels will have significant impacts in our local environment, if any spills occur. 相似文献
Transhumant pastoralism is one of the dominant livestock production systems in West Africa, and it is characterized by seasonal and cyclical movement of varying degrees between complementary ecological areas. The common pattern of transhumance is moving herds from areas with pasture and water scarcity such as the Sahelian zone to areas where the forage and water are found, often in the sub-humid zone. Whereas the transhumant herds from the Sahel are mainly Zebu breeds, endemic ruminant livestock (ERL) are the dominant breeds in sub-humid zone of West Africa because of their tolerance to tsetse-borne trypanosomosis disease. These livestock fulfill different functions in the livelihood of rural communities in the region. To identify potential areas of interventions for sustainable natural resource management to improve ERL productivity, a desk study that included spatial mapping was performed to review and document the existing knowledge on transhumance in West Africa. Additionally, group discussions were held to analyze the (actual or potential) effects of transhumant herds on natural resource management and ERL in the sub-humid zone. This study covered sub-humid zone in The Gambia, Guinea, Mali and Senegal. The key question we addressed in this study was as follows: What are the key trends and changes in transhumant pastoralism and how do these impact sustainable management of natural resources including endemic livestock? The results of the desk study and group discussions showed that there have been more southerly movements by transhumant pastoralists into the sub-humid zone over the past three decades and this has contributed to growing competition for grazing resources. The presence of transhumant herds in the sub-humid zone has a potential impact on management and conservation of ERL through crossbreeding with transhumant Zebu breeds from the Sahel but only study sites in Mali showed a high risk. 相似文献
According to observed twentieth century temperature trends and twenty-first century climate model projections, the region that encompasses the eastern Mediterranean and the Middle East (EMME) is identified as a climate change hot spot. We extend previous studies by a comprehensive climatology of heat waves in the EMME based on regional climate model simulations for the recent past and the end of the twenty-first century. A percentile-based definition of heat waves is used to account for local climatic conditions. Spatial patterns of several heat wave properties are assessed and associated with atmospheric circulation regimes over specific locations. To cover a range of possible future climates, we use three SRES emission scenarios. According to our results, all indices that characterize heat wave severity will strongly increase compared with the control period of 1961–1990. The northern part of the EMME could be exposed to increased heat wave amplitudes by 6–10 °C, and the southern part may experience 2–3 months more combined hot days and tropical nights. Heat wave peak temperatures will be higher due to the overall mean warming as well as stronger summer anticyclonic conditions. The projected changes will affect human health and the environment in multiple ways and call for impact studies to support the development of adaptation strategies. 相似文献
Environmental Science and Pollution Research - Cardiovascular diseases are key complications primarily associated with hyperthyroidism disorders. The present study sought to ameliorate... 相似文献
Environmental Science and Pollution Research - Groundwater resources are the main supply of freshwater for human activities. Nevertheless, during the last 50 years, groundwater has become very... 相似文献
Climate change adaptation in the low laying developing countries is becoming crucial at the present time. However, the local knowledge regarding climate change adaptation is not well focused. This study evaluates climate related perception and identifying various adaptation strategies in the low lying areas of North-Eastern Bangladesh. Six focus group discussions and 120 households?? survey were carried out to identify the major climate events in our study areas which were temperature change, drought, heavy rainfall and cyclone and storm surges. Furthermore, main livelihood problems arising from these events were lack of fish availability, scarcity of water in drought seasons and frequent flood in the rainy seasons. Results also revealed that a little portion (10%) of the respondents had well knowledge about the present climate change. However, seasonal livelihood and hazard calendar demonstrated that local people were increasingly changing their livelihood status with changing climatic hazards. At that situation local people tried to adapt themselves with the changing climate through changing their own behavior and introducing some adaptation strategies. We recognized total 16 adaptive measures in the study areas within which crop diversification, floating garden, duck rearing, cage aquaculture, wave protection walls, re-digging of canal and construction of embankments were popular. The present study revealed that local experiences in the face of climate change adaptation have merits which need special consideration. Continuous research and more incentives required for proper documentation and relegate the local adaptation knowledge in the tropic. 相似文献
This study has applied the concept of the hybrid PAC-UF process in the treatment of the final effluent of the palm oil industry for reuse as feedwater for low-pressure boilers. In a bench-scale set-up, a low-cost empty fruit bunch-based powdered activated carbon (PAC) was employed for upstream adsorption of biotreated palm oil mill effluent (BPOME) with the process conditions: 60 g/L dose of PAC, 68 min of mixing time and 200 rpm of mixing speed, to reduce the feedwater strength, alleviate probable fouling of the membranes and thus improve the process flux (productivity). Three polyethersulfone ultrafiltration membranes of molecular weight cut-off (MWCO) of 1, 5 and 10 kDa were investigated in a cross-flow filtration mode, and under constant transmembrane pressures of 40, 80, and 120 kPa. The permeate qualities of the hybrid processes were evaluated, and it was found that the integrated process with the 1 kDa MWCO UF membrane yielded the best water quality that falls within the US EPA reuse standard for boiler-feed and cooling water. It was also observed that the permeate quality is fit for extended reuse as process water in the cement, petroleum and coal industries. In addition, the hybrid system’s operation consumed 37.13 Wh m−3 of energy at the highest applied pressure of 120 kPa, which is far lesser than the typical energy requirement range (0.8–1.0 kWh m−3) for such wastewater reclamation.