خيارات البحث
النتائج 61 - 70 من 6,560
Effective Factors in Municipal Solid Waste Minimization and Recovery by Making Use of Citizens' Participation; Case Study of a District in Tehran City النص الكامل
2020
Koushki, B. | Nasrabadi, T. | Amiri, M. J.
The purpose of this research is to quantify the potential of waste recycling in the form of participatory scenarios for separation from the source and to study the factors of minimization (reduction) of waste production in a district of Tehran. Amount of waste minimization was determined with considering a couple of citizens' participation scenarios. Source separation of valuable wastes including paper and cardboard, plastic, plastic bags, aluminum cans, bread, PET, waste metal and glass were considered in this procedure. Among 250 tons of generated dry waste within the district, 150 tons (60%) goes directly to landfill instead of getting recycled. Considering the successful experiences regarding the use of reverse vending machine (RVM) in recycling of beverage containers, this research takes RVM as a reasonable method to promote the recycling activities by citizens. In the 10% scenario, the participation for the separation of the total amount of daily materials is about 4,300 USD per day and in the 25% scenario, 10,800 USD of added value have been calculated. Also, for the participation of 10 and 25 percent during a month, 15 and 30 waste disposal services to the disposal and processing complex could get less.
اظهر المزيد [+] اقل [-]Diversity of Lichen Flora in Mt. Kitanglad Range Natural Park, Kaatuan, Lantapan, Bukidnon النص الكامل
2020
Cababan, M.L. | Memoracion, M. M. | Naive, M. A.
This study was conducted to identify and classify the lichens; determine the diversity index and richness of lichens. A total of 36 species belonging to six genera under three families was identified. Lichen species were mostly found at moderate high altitudinal range with an elevation of 1,131 meters above sea level and open areas where they received adequate sunlight with high moisture and humidity contents. Diversity, composition and altitudinal distribution of lichens was evaluated in Mt. Kitanglad Range, Kaatauan, Lantapan, Bukidnon, Philippines a wet forest type forest. The maximum species richness was reported on Usnea rubicunda Stirt. The abiotic factors were shown to be essential in adapting the relative abundance of lichens for it is capable to survive in the range of light levels, it appears that drier and lighter conditions competitively favored. Additionally, lichen diversity is dependent on the climatic and environmental conditions which makes them as an excellent biological indicators of ecosystem changes in the forests of Mindanao Island, Philippines.
اظهر المزيد [+] اقل [-]Modeling and Optimization of Arsenic (III) Removal from Aqueous Solutions by GFO Using Response Surface Methodology النص الكامل
2020
Tabatabaei, F. S. | Izanloo, H. | Heidari, H. | Vaezi, N. | Zamanzadeh, M. | Nadali, A. | Aali, R. | Asadi-Ghalhari, M.
Arsenic is a highly toxic element for human beings, which is generally found in groundwater. Dissolved Arsenic in water can be seen as As+3 and As+5 states. The adsorption process is one of the available methods to remove Arsenic from aqueous solutions. Thus, this papers aims at removing Arsenic (III) from aqueous solutions through adsorption on iron oxide granules. The relation among four independent variables, namely the initial concentration of Arsenic (III), pH, adsorbent dose, and contact time have been investigated through Response Surface Methodology. Design-Expert software and Central Composite Design method have been used to design and analyze the experiments and results. Also, SEM and FTIR analysis have been conducted to characterize the absorbent morphology. The optimum initial concentration of Arsenic (III), pH, contact time, and adsorbent dosage are 30ppm, 5, 49.99min, and 8g/l, respectively. Under these optimum conditions, the Arsenic (III) removal efficiency is 67%. The predicted 2FI model shows the highest Arsenic removal coefficient (R2=0.887).
اظهر المزيد [+] اقل [-]Levels of Fine Particulate Matter Bound Trace Metals in Air of Glass Industrial Area; Firozabad النص الكامل
2020
Rajouriya, K. | Rohra, H. | Taneja, A.
The present study deals with sequential extraction of fine particulate matter (PM2.5) bound trace metals in an industrial area of Firozabad, India. During the study period, daily PM2.5 concentration ranged between 73.49 μg/m3 and 113.26 μg/m3 with poor air quality index of 196.37. In the present study, Ca recorded the highest while Co had the lowest concentration among all analysed metals. Mn, Ni, Pb, Co, and Cu had high bioavailability (34.80%-65.80%) than other elements. Cd, Pb, and Cu were found to be highly enriched (EF> 289-6516) by varied anthropogenic activities. Hazard Quotient (HQ) for Ni, Mn, and Cr and Excess Lifetime Cancer Risk (ELCR) of Cr(VI) and Ni exceeded the respective safer limit (HQ>1 and ELCR≥ 10-6), thus implying serious risk to the receptors. All the metals had the highest concentration in less mobile and residual fraction except for Ni and Co, which inferred greater risk due to their high toxicity. Overall, the results present exposure and risk assessment of metal associated particles; that provides in-depth knowledge of the risk factors through inhalation exposure pathway of particles associated with industrial environment.
اظهر المزيد [+] اقل [-]Qualitative Analysis of Plastic Debris on Beaches of Brunei Darussalam النص الكامل
2020
Qaisrani, Z. | Shams, S. | Guo, Z. R. | Mamun, A. A.
Plastic debris is one of the major environmental concerns for the coastal area of Brunei Darussalam. It reduces the aesthetic appeals of the beaches in the country. The current study investigates marine debris on six different beaches of Brunei Darussalam along the South China Sea. Plastic was found the most abundant among whole debris by number (90.02%) and by weight (39.12%). It was classified by size (micro (<5 mm), meso (5-20 mm), macro (21-100), and mega (>100 mm)), colour (transparent, coloured, white and black). Fourier Transform Infrared Spectroscopy (FT-IR) was used to investigate the types of plastics and additives present in it. Statistical analysis using Minitab 17 and Kruskal-Wallis test was performed for comparison of data at different study sites. All major types of plastics were found in different forms with varying quantities from which toxic chemicals may leach out during degradation. The highest abundance by the number of plastic debris was found on Muara beach with a mean value 74.428 n/m2 ± 34.33 n/m2, while the lowest abundance was found on Lumut beach 53 n/m2 ± 20.9 n/m2. The study shows beaches used for recreational facilities are likely to have more debris as compared to other beaches.
اظهر المزيد [+] اقل [-]Response surface method Optimization of the Dyes Degradation using Zero-Valent Iron based Bimetallic Nanoparticle on the Bentonite Clay Surface النص الكامل
2020
Sabouri, M. R. | Sohrabi, M. R. | Zeraatkar Moghaddam, A.
Immobilizing of zero-valent iron in mono- and bi-metallic systems on the bentonite clay surface as new nanocatalyst were synthesized and used to degrade model acidic dyes from aqueous media. The Fourier-transform infrared spectroscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller analysis were used to characterize the synthesized nanocomposites, which demonstrated successful loading of nanoscale Fe-Cu bi-metallic onto bentonite support. Different variables controlling the congo red, methyl orange and methyl red dyes degradation using zero-valent iron based bimetallic nanoparticle on the bentonite clay surface as new nanocatalyst were concurrently optimized through an experimental design. Basic evaluations proved the nanocatalyst quantity, medium pH, initial dye concentration, and contact time as the most important variables influencing the degradation phenomenon and hence a response surface methodology based on the central composite design was conducted to determine the relations between the variables and the degradation efficiencies. The statistical factors (e.g. R2 and F-value) of the derived models were considered. Using response surface plots obtained through the models, the effects of the variables on the degradation efficiencies for each dye were assessed. Also, the Nelder-Mead non-linear optimizations were performed and the optimal degradation efficiencies at a 95% confidence level were determined which were found to comply with the respective experimental response values.
اظهر المزيد [+] اقل [-]Assessment of Accumulation and Potential Health Risk of Cr, Mn, Fe, Cu, and Zn in Fish from North-Eastern Mediterranean Sea النص الكامل
2020
Can, M. F. | Yılmaz, A. B. | Yanar, A. | Kılıç, E.
Heavy metal accumulation in aquatic organisms has been an important issue due to environmental pollution resulting from anthropogenic activities. In this study, Cr, Mn, Fe, Cu, and Zn in the selected fish species (Mullus barbatus, Solea solea, and Siganus rivulatus) from three consecutive bays (İskenderun, Mersin, and Antalya from North-Eastern Mediterranean Sea) were considered to provide some information on heavy metal accumulation level and assessment of their health risk on both general and fishermen populations. There were some significant differences inter- and intra- species/ tissues/bays. The stability in heavy metal accumulation in fish tissues varied and the most stable tissue for Cr, Cu, Fe, Mn and Zn were determined as skin, muscle, liver, liver and, muscle, respectively. In general, the lowest heavy metal values were observed in the fish muscle. The Target Hazard Quotients (THQ) and Total Target Hazard Quotients (TTHQ) values based on muscle were not exceeded 1.00. Therefore, these results suggest that both general and fishermen populations are not subjected to the significant potential health risk from those bays.
اظهر المزيد [+] اقل [-]Dissipation of butachlor by a new strain of Pseudomonas sp. isolated from paddy soils النص الكامل
2020
Pourbabaei, A. A. | Khoshhal Nakhjiri, E. | Torabi, E. | Farahbakhsh, M.
Butachlor (BUT) is a chloroacetanilide herbicide widely applied to rice paddies to control annual grass and broad-leaf weeds. A BUT-degrading bacterial strain (PK) was isolated from paddy soils. Biochemical and 16S rRNA sequencing characteristics confirmed the strain as Pseudomonas aeruginosa (99% resemblance). The isolate dissipated BUT (100 μg/mL) in an M9 liquid medium with a rate of 0.5 ± 0.03 day-1 and DT50 and DT90 of 1.38 ± 0.10 days and 4.58 ± 0.32 days, respectively. Soil dissipation of BUT was investigated under flooded conditions. In sterile soils, the isolate increased the dissipation of BUT (200 μg/g) (DT50 = 12.38 ± 1.83 days, DT90 = 41.12 ± 6.09 days, k = 0.06 ± 0.01 day-1) compared to sterile non-inoculated samples (DT50 = 26.87 ± 2.82 days, DT90 = 89.25 ± 9.36 days, k = 0.03 ± 0.00 day-1). In non-inoculated non-sterile soil experiments, the dissipation of BUT was faster (DT50 = 15.17 ± 2.11 days, DT90 = 50.38 ± 7.02 days, k = 0.05 ± 0.00 day-1) compared to non-inoculated sterile ones, and inoculating the isolate accelerated the removal of BUT in non-sterile soils significantly (DT50 = 8.03 ± 1.20 days, DT90 = 26.68 ± 3.97 days, k = 0.09 ± 0.01 day-1). BUT inhibited soil respiration (SR) initially for 5 days, followed by an increase until day 20. The increase in SR was more pronounced in the co-presence of BUT and the isolate. The results of this research suggest P. aeruginosa PK as a suitable candidate for BUT bioremediation.
اظهر المزيد [+] اقل [-]A Regression-Based Analysis to Assess the Impact of Fluoride Reach River Water on the Groundwater Aquifer Adjacent to the River: A Case Study in Bharalu River Basin of Guwahati, India النص الكامل
2020
Das, M. | Bhattacharjya, R. K.
Fluoride is one of the parameters which is non-degradable and naturally occurring inorganic anion found in many natural streams, lakes, and groundwater. Serious problems are faced in several parts of India due to the high consumption of fluoride through drinking water. These may cause dental and skeletal fluorosis to humans. This study aims to examine the level of fluoride in both Bharalu river water and groundwater within Guwahati city, Assam, India, and also to analyze the impact of fluoride reach river water on the groundwater aquifer adjacent to the river. From the investigation, it has been observed that the concentration of fluoride varies from 0.02 to 3.73 mg/l in river water and 0.04 to 4.7 mg/l in the case of groundwater. The statistical analysis shows that there is a strong correlation between the fluoride concentration of river water and groundwater. This indicates that the groundwater might have contaminated by the polluted river water.
اظهر المزيد [+] اقل [-]Synthesis and Characterization of Zero Valent Iron Nanoparticles for Textile Wastewater Treatment النص الكامل
2020
Nigam Ahuja, N. | Ansari, A.A. | Rajput, R. | Singh, P.
Textile manufacturing industry produces a huge amount of pollutants from its textile dyeing units. To combat the problem of water pollution, various processes are being already adopted by textile industries to treat wastewater before its discharge into the nearby environment. However, the inadequate traditional treatments are leading towards the development of different technologies with major concern on material’s high efficacy. One of the newest advancement in this area is nanotechnology. The zero valent iron nanoparticles (nZVI) are gaining extreme importance, due to its potential capabilities of reducing chemical substances, dye colour and other constituents from the waste effluent. In the present article, synthesis of nZVI particles was carried out by borohydride chemical reduction method using ferrous heptahydrate sulphate salt. Its characterization such as surface morphology and structure was analyzed by using X-Ray diffraction (XRD), Scanning Electron Microscope (SEM) and Brunauer- Emmett-Teller method (BET). Further, the stability of nanoparticles was also investigated via chemical and thermal processes at different pH ranges and temperatures. The results revealed that the synthesized nanoparticles were as per the available literature in terms of size, surface morphology, structure & stability. Hence, ready for the batch experimental studies on laboratory scale.
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