细化搜索
结果 71-80 的 640
Response Surface Methodology for Adsorption of Humic Acid by Polyetheretherketone/ Polyvinylalcohol Nanocomposite Modified with Zinc Oxide Nanoparticles from Industrial Wastewater
2023
Pournamdari, Elham
The applicability of Polyetheretherketone/Polyvinylalcohol Nanocomposite Modified with Zinc Oxide Nanoparticles synthesized for eliminating humic acid rapidly from industrial wastewater. Identical techniques, including BET, FTIR, XRD, and SEM have been utilized to characterize this novel material. Also, the impacts of variables including initial humic acids (HAs) concentration (X1), pH (X2), adsorbent dosage (X3), and sonication time (X4) came under scrutiny using central composite design (CCD) under response surface methodology (RSM). The values of 10 mgL-1, 6.0, 0.025 g, and 5.0 min were investigated through batch experiments, considered as the ideal values for humic acids (HAs) concentration, pH, adsorbent dosage, and contact time, respectively. Adsorption equilibrium and kinetic data were fitted with the Langmuir monolayer isotherm model and pseudo-second-order kinetics (R2: 0.999) with maximum adsorption capacity (102.0 mgg-1), respectively. The overall results confirmed that Polyetheretherketone/Polyvinylalcohol Nanocomposite Modified with Zinc Oxide Nanoparticles could be a promising adsorbent material for humic acids (HAs) removal from industrial wastewater.
显示更多 [+] 显示较少 [-]Effect of Polychlorinated Biphenyls on Biochemical Parameters of the Black Sea Bivalve Mollusk Mytilus galloprovincialis Lam.
2023
Skuratovskaya, Ekaterina | Serbin, Artem
Polychlorinated biphenyls (PCBs) are known amongst the most dangerous toxicants entering the coastal marine waters from various polluting sources. Even the smallest PCBs doses are capable to change physiological and biochemical processes exerting toxic, mutagenic and carcinogenic effects. So, the aim of this study was to analyze the impact of PCBs at 1, 100, 1000 µg/L on oxidative stress parameters (level of oxidized proteins (neutral aldehydes and ketones, basic aldehydes and ketones) and lipid peroxidation), antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT)) and cholinesterase (ChE) activity in the hepatopancreas of mussel Mytilus galloprovincialis during 5 days’ of the toxicological experiment. Level of all forms of the oxidized proteins was found significantly increased at 100 µg/L and 1000 µg/L (+50-78% and +150-282%, respectively) compared to the control (p<0.05). Level of lipid peroxidation was considerably higher at 1, 100, 1000 µg/L (+59%, +134%, +269%, respectively) compared to the control (p<0.05). SOD activity significantly raised at 1, 100, 1000 µg/L (+63%, +200%, +118%, respectively) compared to the control (p<0.05), while CAT activity reduced at 1000 µg/L compared to the control, 1 µg/L and 100 µg/L (-29%, -66%, -40%, respectively) (p<0.05). ChE activity was found lower at 1, 100, 1000 µg/L (-60%, -93%, -30%, respectively) compared to the control (p<0.05). Possible mechanisms of M. galloprovincialis biochemical response to PCBs are discussed. Studied biochemical parameters can be suitable biomarkers for evaluating the toxicity of PCBs and M. galloprovincialis can be used as a bioindicator in the monitoring of marine ecosystems contaminated with these pollutants.
显示更多 [+] 显示较少 [-]Recovery of the fixing solution waste and silver, as well as the direct synthesis of silver nanoparticles from the solution waste
2023
Azordeh, Soheila | Asadi, Mehdi
Radiology and photography films are mainly made of silver halides, which are very sensitive to light. The developer-fixing solution reduces silver salt crystals and turns them into black metallic silver on film and a stable and clear image appears on the film. After several uses of the fixing solution, its efficiency is reduced due to the decrease in the concentration of sodium thiosulfate and finally, it cannot be used since there is not enough awareness regarding its harm, so it enters the environment through wastewater. In this study, the recovery of fixing solution waste has been investigated. The recovery of the solution waste, silver extraction, and direct synthesis of nanoparticles have been performed by chemical reduction method from the waste. The obtained samples were analyzed and studied by EDX, XRD, and SEM techniques. The results showed that the fixing solution waste and silver metal were recovered properly with a purity of 99.81%. Also, AgNPs were synthesized by chemical reduction. Recovery of the fixing solution waste -for the first time- and metallic silver, as well as the synthesis of AgNPs by chemical reduction method, is an economical method and free of any contamination.
显示更多 [+] 显示较少 [-]Using of a Moran’s I and Hot Spot Analysis to Identify of Thoron in Najaf City using GIS Software
2023
Hussein, Ali | Dosh, Rukia | Abojassim, Ali
AGIS method based on spatial autocorrelation analysis used to identification and ranking of thoron (220Rn)concentration. Spatial radiation patterns are analyzed using Moran's I statistic. Getis-Ord Gi* is utilized to locate clusters of high and low measurements and create a map of thoron hot spots. One hundred schools in the center of Najaf City were examined for thoron using CR-39 detectors (produced from Track Analysis Systems Ltd., UK) for this research. Average thoron levels were 2.99 Bq/m3, with a range of 9.00 Bq/m3 to 0.22 Bq/m3. The radiation levels found in this investigation were significantly lower than the UNSCEAR 2000 safety standards of 40 Bq/m3. Moran's, I have used it to analyze the clustering of districts across a research region and to measure the spatial distribution of data. Getis-Ord Gi* statistics were used to identify cold and hot spots within the research area. Thoron concentrations were shown to have insignificant spatially random distribution patterns, as demonstrated by Global Moran's I. (Moran’s I =0.28, p-value=0.24).
显示更多 [+] 显示较少 [-]Increasing the Accuracy in Forecasting the Surface Drifter Trajectory by Using Data Assimilation
2023
Abbasi, Mahmud Reza
Predicting the path of pollution in the marine area is one of the most important concerns for those involved in environmental studies. In this paper, we have discussed the capabilities of using the data assimilation method in the FVCOM numerical model in forecasting the movement path of a surface drifter in the Strait of Hormuz. Initially, the FVCOM model was implemented for particle tracking by using environmental data in the Strait of Hormuz. Then tidal gages data of the Strait of Hormuz were assimilated in the numerical model using the nudging method. The results of the two runs were compared with field measurements data using statistical parameters such as bias and correlation coefficient. Statistical analysis and visual comparisons depicted the ability of data assimilation in optimizing the model water level outputs and reducing the differences between drifter location and model results and also the rate of the distance between them.
显示更多 [+] 显示较少 [-]Environmental Geochemistry of some Heavy Metals and the Radioactivity in Urban Subsurface Soils, Southeast-Baghdad
2023
Saleem Al-Ankaz, Zinah | Issa Muslim, Ruaa | Salman. Amana, Maitham
A geochemical evaluation was performed to determine the occurrences of many heavy metals as well as their natural activities, in the southeast-Baghdad. For this purpose, seventeen subsurface soil samples from the cited location were collected at a depth of 50-100 cm. Samples collection included many types of land uses such as open space, roadside, green land, industrial and commercial samples. The samples were characterized systematically using XRF and gamma-ray spectrometry with NaI (Tl) scintillation detector. The total average concentrations of heavy metals Ag, Sn, Sb, I, Hf, W, Th and U in the soil were 1.94, 3.13, 3.01, 2.82, 1.70, 72,5.66 and 0.85 ppm respectively. Heavy metals Sn, I and W appeared with high concentrations among the others as shown in total average, compared with the standard. The enrichment with Sn elements strictly appeared in green and commercial lands with an average 3.63 ppm, whereas I and W concentrated in industrial land 3.0 and 0.95 ppm respectively, indicating anthropogenic rather than autogenic. It was asserted that the observed elements can be used as pollution indicators to discover the state of the contamination. The EF values of the soils in some sites displayed enrichment with Sb and moderate with Ag reflected mild enrichment (EF > 2), confirming their level of pollution by the hazardous heavy metals. The contents of 238U, 232Th and 40K in the samples varied from 34.64-48.54, 47.22-67.73, and 323.27-585.11 Bq/kg, respectively. The mean activities of 238U, 232Th and 40K in the dry weight samples were correspondingly 41.25, 56.89, and 424.12 Bq/kg, which were higher than the global averages of 35, 30 and 400 Bq/kg, respectively. The radium equivalent levels in all samples were much lower than the global average (370 Bq/kg). In addition, all external and internal hazard indices were within the recommended limit. The average dose rate and gamma index levels were greater than the global average value.
显示更多 [+] 显示较少 [-]Effective Removal of Indigo Carmine in Aqueous Solutions using a Low-Cost Adsorbent Developed from Corn Husk Waste: Synthesis, Batch, and Optimization Studies
2023
Handayani, Tuti | Emriadi, Emriadi | Deswati, Deswati | Ramadhani, Putri | Zein, Rahmiana
Acid-activated corn husk waste (CHW) was used to investigate the adsorption mechanism of Indigo Carmine (IC) dye from an aqueous solution. The effect of different operating parameters such as pH (1-7), initial IC dye concentration (40-400 mg/L), contact time (5-75 min), and heating temperature (25–200 °C) was measured on the removal of IC dye by the CHW. The maximum uptake of IC dye was observed at an initial pH of 2. The maximum capacity of 13.57 mg/g and the maximum dye removal of 89.01 % in wastewater. The adsorbents were characterized using Fourier Transforms Infrared Spectrophotometry (FTIR), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray Fluorescence (XRF), and Thermogravimetry Analysis. The characterization process reveals the differences in adsorbent characteristics before and after the adsorption processes. The Langmuir showed the best fitting (R2 = 0.977) and described multilayer adsorption on diverse surfaces. The pseudo-second-order kinetic model best correlated with the experimental data (R2 = 0.981). Thermodynamics revealed that adsorption was favorable spontaneous and exotherm. The study's results indicated that using CHW as a low-cost adsorbent to treat IC dye was efficient and beneficial to the environment.
显示更多 [+] 显示较少 [-]Effect of Water Soluble Organic Carbon (WSOC) and Polycyclic Aromatic Hydrocarbons (PAHs) emitted by BioChar from the Rubber Sheets Processing Sewage Sludge Combustion
2023
Lakachaiworakun, Putipong | Dangwilailux, Panya | Eakvanich, Visit | Kalasee, Wachara
The total particle mass concentration, size distribution, pH form, polycyclic aromatic hydrocarbons (PAHs) value, the concentration of total Benzo[a]pyrene Toxic Equivalence (BaPTE) and water-soluble organic carbon (WSOC) of smoke particles from the rubber sheets processing sewage sludge biochar burning were studied. In this work, the temperature was measured at 500 mm above the fire base by using K-type thermocouples and a continuously data logger. The result showed that the measured temperature value increased when decreasing the biochar moisture content. The highest average total smoke particle mass concentration values at the initial burning time was found to be 17.53 to 35.27 mg/m3 and then it was persistently reduced until the 60th minute, when the burning was stopped. The pH of biochar's smoke particles was higher than it was before combustion. The total smoke particle mass concentration, the mass median aerodynamic diameter (MMAD) and PAHs values decreased with increasing burning period and decreased the biochar moisture content. The largest BaPTE emission was observed at the highest moisture content, which was within the range of the greatest particle mass (less than 0.43 micron) in an initial combustion period. This value was about 60% that of a given the total value of BaPTE concentration. Meanwhile, the amount of PAHs, the BaPTE concentration and WSOC were depended on the smoke particle number, moisture content and combustion period.
显示更多 [+] 显示较少 [-]Integrated Environmental Assessment of Unsustainable Exploitation and Pollution of Shared Water Resources in Transboundary Basins of Semi-arid and Arid Regions. Case Study: Tigris-Euphrates River Basin
2023
Zebardast, Lobat | Balist, Jahanbakhsh | Karimi, Hazhir
River basins perform the crucial role of providing water resources, especially in arid regions. Due to the nature of interconnection, human interventions and natural events will cause cumulative impacts on the downstream parts of river basins. The aim of this research is to identify and evaluate the impacts of interventions and changes occurring in the upstream of the Tigris-Euphrates River Basin on the downstream parts and provide strategies to reduce and control those effects. To achieve this purpose, multi-scaled investigation of the changes and dynamics of the land cover was performed and the causes and consequences of these changes were investigated using the Driving force-Pressure-Sate-Impact-Response (DPSIR) framework. The results displayed an increase in the area of artificial lakes and agricultural lands and a decline in the area of rangelands and natural wetlands, especially in the downstream of the basin. The state of the ecosystem was under the influence of Driving forces such as population and industrial growth and political competitions of the littoral states, which led to pressure on the limited water resources and development of water management and control projects. The overall trends of changes in the state of the environment had created impacts on the ecosystem and communities that required urgent responses from the riparian countries. Finally, to foster water cooperation instead of non-constructive completions in this region, a framework was developed with an emphasis on creating a union of riparian countries and using their scientific potentials to provide effective and impartial solutions.
显示更多 [+] 显示较少 [-]Effect of Copper on Cadmium-Resistant Plants of Agrostis stolonifera
2023
Aleksandrovich Gladkov, Evgeny | Nikolaevna Gladkova, Olga
Environmental pollution with heavy metals has a negative impact on lawn grasses. Heavy metals are one of the priority pollutants of anthropogenic ecosystems. Earlier, plants Agrostis stolonifera, resistant to cadmium, were obtained using biotechnological method. Plants that are resistant to one heavy metal may be cross-resistant to another. The assessment of the resistance of plants obtained by biotechnological methods to other heavy metals is of practical value. The object of our study was to lawn grass - Agrostis stolonifera L. The aim of this work was to assess the tolerance of the next generation descendants of the regenerant Agrostis stolonifera, resistant to cadmium, to one of the most phytotoxic heavy metals - copper. Cadmium -tolerant plants were more resistant to copper. The tolerance of cadmium – resistant plants to copper is associated with nonspecific mechanisms. However, the increase in plant resistance was not very significant. Therefore, it is more expedient to obtain plants that are resistant to copper.
显示更多 [+] 显示较少 [-]