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Результаты 311-320 из 62,084
Nanocomposites for Packaging Applications: Synthesis, Characterization, Thermal and Microbial Degradation of Its Residues for Plant Growth
2022
Abbasi, Zahra | Motamedi, Hossein | Zirrahi, Zinat | Taghavi, Mehdi | Farrokhnia, Abdolhadi | Aghaie, Ermia | Behnamian, Yashar
Environmental pollution, caused by traditional plastic packaging, has recently become more severe due to non-biodegradable nature of petroleum-based plastics. The present research studies the preparation of polyvinyl alcohol (PVOH)/Starch (ST)/Humic Acid (HA) contained sodium montmorillonite clay (MMT) as a plastic packaging method. It also investigates biodegradability of films in terms of microbial and thermal degradation and their residual effect on plant growth. For doing so, the research utilizes Broido Technique to obtain the activation energy of the films’ thermal degradation. The influence of HA/MMT ratio on the surface morphology and physical characteristics has also been assessed, using the Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscope (SEM), and thermogravimetric analysis (TA). After 12 days of microbial degradation, the total remaining solids are 32.12 wt% (PVOH/ST/HA (3%)/MMT (1%)); 48.17 wt% (PVOH/ST/HA (3%)/MMT (3%)), and 58.82 wt% (PVOH/ST/HA (1%)/MMT (3%)). The research shows that the highest activation energy for PVOH/ST/HA (3%)/MMT (3%) is 75 kJ/mol.
Показать больше [+] Меньше [-]Spatio-Temporal Variation of an Aquifer Salinity in a Semi-Arid Area, Case Study of Sarvestan Plain, Iran
2022
Rasti, Moslem | Nasrabadi, Touraj | Ardestani, Mojtaba
The aim of this study is to determine the amount of quantitative and qualitative changes in groundwater in the Sarvestan plain in south of Fars province, which is one of the critical plains in Iran in terms of water resources. In this research, zoning maps of electrical conductivity of water in GIS were prepared and various hydrochemical diagrams were illustrated. Different quality parameters of water resources were compared according to the statistical data collected and the experiments performed at the beginning of the 8-year period of the research. Chemical analysis of water samples shows that the groundwater type of most of the studied wells at the beginning of the period (2013) has changed from Ca-Cl and Mg-Cl types to Na-Cl type at end of the time period (2020). Determining the trend of chemical changes shows that the diversity of water samples in terms of anions and cations in water with increasing salinity at the end of the period is less than the variety of samples at the beginning of the period. According to the results of chemical experiments, evaporation, crystallization, and weathering of rocks are the factors that control the composition of groundwater in the study area. This study shows increasing the salinity of groundwater in addition to decreasing precipitation and high water use for agricultural application, due to the type of geological formations, especially the presence of salt domes at groundwater inlets to the plain on the east side of the study area.
Показать больше [+] Меньше [-]Biosorption of Chromium by Fungal Strains Isolated from Industrial Effluent Contaminated Area
2022
Narolkar, Swati | Mishra, Arvnabh
The ability of fungi to act as bio-sorbent had been extensively evaluated and has shown excellent metal sequestering ability for heavy metals such as cadmium, copper, zinc, lead, iron, nickel, radium, thorium, and uranium from aqueous solution. In the present study, tolerance, removal efficiency and adsorption capacity of hexavalent chromium using isolated fungal strains were analysed. Total nine fungal isolates were obtained from organic pollutants and metals contaminated Gujarat Industrial Development Cooperation sites. Filamentous fungi isolated belonged to Aspergillus spp., Rhizopus spp., Trichoderma spp., and Penicillium spp. Chromium sorption experiments using isolated fungal strains were carried out to check adsorption capacity and adsorption intensity. At higher chromium concentration, removal efficiency and adsorption capacity were observed in the order of Aspergills candidus > Aspergillus ochraceus > Aspergillus flavus > Rhizopus spp. > Trichoderma spp. A. candidus showed higher adsorption capacity, 5.49mg/g with 98.75% chromium removal efficiency at 150ppm of hexavalent chromium. The observed RL value for Langmuir isotherm for all the three concentrations was less than 1, depicting favourable sorption and in Freundlich isotherm, the value of 1/n exceeds more than 1 showing co-operative or similar type of adsorption.
Показать больше [+] Меньше [-]Annual Effective Dose Assessment of Radon in Drinking Water from Abandoned Tin and Cassiterite Mining Site in Oyun, Kwara State, Nigeria
2022
Orosun, Muyiwa Michael | Ajibola, Taiye Benjamin | Ehinlafa, Olusegun Emmanuel | Issah, Ahmad Kolawole | Salawu, Banji Naheem | Ishaya, Sunday Danladi | Ochommadu, Kelechi Kingsley | Adewuyi, Abayomi Daniel
Mining activities are generally known to enhance the concentration of primordial radionuclides in the environment thereby contributing immensely to human exposure to ionizing radiation of terrestrial origin. Thus, the abandoned Tin and Cassiterite mining site in Oyun, Kwara State, Nigeria, is believed to cause radiological implications on local residents. Assessment of radon concentration in surface water from the study area was carried out using RAD7-Active Electronic detector big bottle system. In order to ascertain the risk or hazard incurable in consuming such water, 12 samples were analysed and used in the estimation of annual effective dose of radon. The measured maximum and minimum radon concentrations were found to be 44.95 and 21.03 Bq/L with average of 35.86 Bq/L. These values are quite greater than the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) recommended limits of 11.1.Bq/L. The estimated total effective dose (AEDEtotal) was found to be within the range of 206.52 and 441.41 μSvy-1, and an average of 352.20 μSvy-1 for Adults, 283.30 and 605.47 μSvy-1, and average of 483.10 μSvy-1 for Children, and finally, 321.70 and 687.47 μSvy-1 with average of 548.64 μSvy-1 for Infants, respectively. These values were higher than the recommended limit of 100 µSvy-1 and 200 µSvy-1 for adult and children respectively. Furthermore, worries should be noted about the probabilistic cumulative effect on the consumers of such water if the ingestion is for an extended period of time.
Показать больше [+] Меньше [-]Atmospheric Aerosol Loading and Properties over India: A review
2022
Mor, Vikram | Dhankhar, Rajesh
Atmospheric aerosols are very crucial from air pollution and health perspective as well as for regional and global climate. This paper attempts to summarize the aerosol loading and their properties such as Aerosol Optical Depth (AOD), Single Scattering Albedo (SSA), Angstrom exponent, and Radiative forcing, over India. All the above mentioned parameters have shown significant variability with change in the site and season. From various studies it was observed that AOD is relatively higher over Northern part of India as compared to Southern and Eastern part. Generally, lower values of SSA were observed over all sites during winter and post-monsoon seasons which indicates the dominance of absorbing type aerosol during these seasons. Also the ARF within atmosphere showed comparatively higher values during November-December and lower value during August and September all over the India. The current state of knowledge about aerosol sources, interactions and their effects on environment is limited because of its complexity. Therefore, more focused research in needed to understand the aerosol’s role in climatic phenomenon.
Показать больше [+] Меньше [-]Environmental Performance of Alternative Schiff Bases Synthesis Routes: A Proposal for CO2 Storages
2022
Yaseen, Anahed A. | Yousif, Emad | Al‐Tikrity, Emaad T. B. | Kadhom, Mohammed | Yusop, Muhammad R. | Ahmed, Dina S.
The increased consumption of fossil fuels provokes high levels of carbon dioxide (CO2) emissions, which give rise to serious environmental issues. Accordingly, designing and utilizing new classes of materials, such as Schiff bases, to capture CO2 gained significant attention from researchers worldwide. In the present work, two Schiff bases were synthesized and examined as storage materials for carbon dioxide gas. The prepared compounds were obtained by reacting trimethoprim with two aldehydes severally (benzaldehyde and parabromobenzaldehyde) in boiling methanol. The surface morphology of the compounds was investigated via field emission scanning electron microscopy (FESEM). The Brunauer-Emmett-Teller (BET) test showed that Schiff bases 1 and 2 have surface areas of 17.993 and 2.732 m2/g, pore volumes of 0.008 and 0.005 cm3/g, and pore diameters of 17.02 and 74.89 nm, respectively. Reasonable uptake values of CO2 (31.36 cm3/g, 6.2 wt%) and (25.30 cm3/g, 5.0 wt%) were achieved by the prepared Schiff bases 1 and 2, respectively, at 313 K temperature and 40 bars pressure.
Показать больше [+] Меньше [-]Efficacy of Natural Coagulants in Treating Sugar Industry Effluents
2022
Garika, Nihanth Soury | Dwarapureddi, Bhavya Kavitha | Karnena, Manoj Kumar | Dash, Swathi | Raj, Aman | Saritha, Vara
Industrial sector is understood to be one of the major offenders in polluting environment particularlywater among others. Sugar industry is one among the agro-based industry releasing high organicpollutants rich in BOD. Though conventional treatment methods have been employed in treating sugarindustry effluents at varied degrees, they come with their own setbacks. In this direction naturalcoagulants are explored and evaluated for their potential and efficiency towards treating sugar industryeffluents. The process of coagulation and flocculation removes impurities precisely colloidalimpurities through the phenomenon of destabilization, bridging and sweep coagulation. In order tohave an effective treatment factors governing coagulation are to be optimized to determine the dose,pH, mixing time etc. The prime objective of the present study is to characterize the sugar industryeffluents, test the efficiency of both chemical and natural coagulants to treat these effluents and bringout a comparison and potential of natural coagulants with that of chemical coagulants. Jar testapparatus was employed all coagulation studies and the results were promising with reduction inparameters like colour (99.28%), electrical conductivity (60.39%), turbidity (97.67%), chloride(69.23%) and total dissolved solids (60.42%) highest by ferric chloride followed by the naturalcoagulants. The findings of the study suggest that the lowest dose of 0.25g/l was optimum to removethe physico-chemical parameters both by chemical and natural coagulants and since natural coagulantswere equally competent with chemical coagulants these can be substituted towards achieving greentreatment options.
Показать больше [+] Меньше [-]High Content of Sulfur in Liquid Stream Removal via new Carbonous Nano Adsorbent: Equilibrium, Kinetic study
2022
Meshkat, Seyyed Salar | Hosseini Dastgerdi, Zeinab | Abkhiz, Vahid | Hagh Shenas, Asieh
This research evaluates dibenzothiophene (DBT) adsorptive removal from the liquid stream on the graphitic carbon nitride (GCN) as a synthesized adsorbent at 25 0C with 3 g for 600 min. The morphological properties of GCN have been investigated by Brunauer–Emmett–Teller (BET), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD). The study of the characteristic properties of nano adsorbent proves the suitability of the synthesized GCN in mercaptan adsorption process with the obtained data showing a good agreement with Freundlich model. The equilibrium capacity of DBT adsorption has been calculated at about 39.1 mg/g. This has also been 25.8 mg/g for TBM (tertiary butyl mercaptan). The adsorption capacity has increased by adding to the adsorbent dosage. Thermodynamic studies expose the negative values for ΔS0 (-8.99 kJ/mol. K), ΔH0 (-21.05 kJ/mol), and ΔG0 (8.91 kJ/mol), which demonstrate that DBT adsorption has been a natural exothermic process. In addition, this experiment verifies that the substitution of N into the carbon structure improves the DBT removal efficiency in comparison with pristine CNT as an adsorbent. The removal efficiency of DBT onto GCN has been approximately 80%, i.e. 20% higher than that of pure CNT. Results show that the adsorption capacity of DBT as a cyclic source of mercaptan has been higher than Tertiary butyl mercaptan (TBM) as a liner one. The DBT adsorption mechanism is done by π–π electron interactions between the aromatic structures of DBT, lone-pair electrons of the S atoms, and the pyridinic GCN planes band.
Показать больше [+] Меньше [-]Constructed Wetlands: A sustainable way of Treating Wastewater in Cold Climate - A review
2022
Singh, Adarsh | Katoch, Surjit | Bajpai, Mukul | Rawat, Akash
The use of constructed wetland (CW) is a natural way of treating wastewater sustainably and economically. However, the implementation of these systems in freezing conditions is still a matter of research and development. The treatment capacity of CWs relies largely on the biological and biochemical processes which further depends on physical conditions such as temperature, solar radiations, etc. Application of wetland systems for treating wastewater faces many challenges in regions with cold climates, resolving which this review has been made. This paper presents a thorough understanding of the components of CWs and their role in contaminant removal. A comprehensive review of the different types of CWs has been done describing the treatment efficiency achieved by its implementation in the cold climate. Furthermore, various technologies which can be clubbed with CWs have also been listed along with the treatment efficiencies obtained. Literature survey indicates that the extent of removing organics (COD and BOD5) and total phosphorous (TP) are not likely to be affected, but total nitrogen (TN) removal appears to slow down at low temperatures. Despite several advantages of CW technology, further research is required to select suitable macrophytes and optimum design parameters to compensate for frigid conditions.
Показать больше [+] Меньше [-]Air Pollution Tolerance Index (APTI) and Expected performance index (EPI) of Selected Plants at RGSC, (BHU), Mirzapur, India
2022
M D, Anil | Pandey, Kumar | Krishna, Vijai | Kumar, Manish
This study carries the evaluation of tolerance of sixteen plants against pollution. These plants have been selected and assessed for several phyto-socio-economic (tree height, canopy, type of tree, laminar structure, hardiness and economic value) and biochemical qualities (pH, Relative water content (R), Ascorbic acid (AA), Chlorophyll a (Chl a), (Chl b), Carotenoids (Car) and total Chlorophyll (TC)) and tested for Air pollution tolerance index (APTI) and Expected performance Index (EPI) and then EPI score used as grades of plants (Not Recommended, Very poor, Poor, Moderate, Good, Very good, Excellent and Best Plus Plant). Statistical analysis tool like correlation matrix among plant parameters and ANNOA test has been applied to understand the relationship among plant parameters and plant species. The best EPI score means best suited plant for the area for plantation and green belt development while plant with lower EPI may be used as bioindicators for the pollution because they are very sensitive for the air pollution.
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