خيارات البحث
النتائج 71 - 80 من 616
Natural Biodegradation Rates of Single-Use Blended Bioplastic Packaging Nylon Entrenched In Freshwater and Marine Water Environments of the Tropics النص الكامل
2023
Dada, Omotola | Bada, Adeola | Okorodo, Emmanuel
The biodegradation rates of single-use blended bioplastic packaging nylon, nylon 6, and cellulose polymer were assessed in aquatic environments in an attempt to identify real biodegradable bioplastics (RBB). The natural biodegradation rates of the test samples in freshwater and marine water were assessed by respirometric method following the procedure of the American Standard Testing and Materials. The experimental design was arranged thrice in a completely randomized design of 2x4x3. The physicochemical parameters were obtained using the standard methods while the rates of biodegradation were obtained by titration method. Data obtained were analyzed using descriptive statistical method. At the end of 120 days, there were steady increase in the rates of biodegradation of cellulose and bioplastic samples across the fourth month in both freshwater and marine water. However, the rate of biodegradation in marine water were higher than in freshwater following the trend cellulose in marine (342 %) > cellulose in freshwater (259%) > bioplastics packaging nylon in marine (193%) > bioplastics packaging nylon in freshwater (175%). For nylon 6, the rate (-14) of retardation in the biodegradation process in Nylon 6 soaked in marine water is greater than that of Nylon 6 soaked in freshwater (-13). Consequently, nylon 6 was recalcitrant to biodegradation both in freshwater and marine water. The study concluded that the blended bioplastic packaging nylon is a real biodegradable bioplastic and could be suggested as a feasible and environmentally-friendly option to replace traditional plastics in the society.
اظهر المزيد [+] اقل [-]Study of Contaminants in Iranian Drinking Water and their Health Outcomes: A Review النص الكامل
2023
Fadaei, Abdolmajid
Contamination of ground and surface water resources with Nitrate (NO3), Fluoride (F), Trihalomethanes (THMs), radon, and heavy metals is the most important global concern due to its possible health risks to people. This study reviews the drinking water contaminants and their health outcomes examined in Iran. A review search was conducted using Scopus, Web of Knowledge, PubMed, and Embase databases for associated released articles from 2014 to 2023, resulting in 86 articles relevant to the objective of this study. According to the results of this review, different emerging contaminants were found in potable water, including THMs, NO3, F, radon and heavy elements (i.e., As, Pb, Ni, Cd, Zn, Cu, and Cr). Health outcomes of exposure to radon, F, NO3, THMs, and heavy metals in potable water have been expressed in various epidemiological research studies. More than 65% of the studies reported hazard index (HI) or hazard quotient (HQ) of heavy elements to be greater than one in potable water in Iran for infants, children, teenagers, and adults. Children and infants are at higher health risk than adults in these areas. The level of Arsenic, Cadmium, Lead, Nickel, Zinc, and Chromium, in 26, 26, 17.39, 13.04, 8.69, and 4.3% of the papers was more than the allowable limits, respectively. Various groups of emerging pollutants have been found in potable water in Iran, while epidemiological research studies on their health outcomes are still insufficient.
اظهر المزيد [+] اقل [-]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 النص الكامل
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.
اظهر المزيد [+] اقل [-]Assessment of Non-Ionizing Radiation Emissions from Cell Phone Towers النص الكامل
2023
Alkhalidi, Murtadha | Al-Shakban, Mundher | Kalifa, Ahmed | A. Abdul Ridha, Hamzah
People’s growing anxiety, and fear of the issue of a large number of mobile phone towers, as well as the lack of studies dealing with this issue at the level of the country in general, and the governorate in particular. All these reasons led to the issue of non-ionizing rays given off by mobile telephone masts on the table of worries about how this radioactivity will affect people's health. Non-ionized radiation emissions were measured by taking 280 readings for the three frequency packets 900, 1800, and 1840 MHz, which are sequential-Global System Mobile (GSM), of 20 cell phone towers in the Al-Amara, the city center of Misan prefecture. Four readings were collected for each frequency, with the highest value for overlap between electromagnetic field and frequency being chosen. A selective Radiation Meter (SRM-3006) was the device used in this study. It was found that the amount of non-ionizing radiation emitted by the towers taken in the study, and for the frequencies (900, 1800, and 1840 MHz) was, in a successive manner (309 × 10-8, 7 ×10-8, and 1109×10-7 MHz). Thus, the measured values of radiation were less than the surveyed limit (4×10-1 μW/cm2) provided for by the law of Iraq’s Determinants for Non-ionized Radiation Emissions (IDNREs).
اظهر المزيد [+] اقل [-]Fuzzy Inference of Air Quality – A case study of Vadodara City النص الكامل
2023
Seema, Nihalani
Abstract: Air Quality Index (AQI) is derived from a series of observations of different air pollutants for reporting air quality. The severity of air pollution and its impacts on the general public are typically reported using the air quality index. Different methods have been developed by various regulatory agencies and scientists, to calculate the AQI using aggregation methods involving critical pollutants. This paper presents a comparison between conventional AQI and Fuzzy AQI. 20 sampling locations were chosen for Vadodara city in order to investigate the effects of urban air pollution, and ambient air quality was measured twice a week from October 2017 to February 2018. The Central Pollution Control Board (CPCB) method formulas were used to calculate the traditional Air Quality Index using the measured values of Coarse particulate matter (PM10), Sulphur dioxide (SO2), and Oxides of nitrogen (NOX). Additionally, the membership functions were provided as input to the Mamdani fuzzy inference system (FIS) for the fuzzy logic system, and the fuzzy air quality index (FAQI) was calculated. The computed conventional AQI values were compared with FAQI values. A close co-relation was observed between conventional AQI and fuzzy AQI values. The application of the fuzzy inference system demonstrates its capability to manage difficult issues including data ambiguity. The findings clearly show that the FIS is capable of resolving inherent discrepancies and interpreting complex conditions.
اظهر المزيد [+] اقل [-]Performance Evaluation of Different Soil Media by Batch-Operated Pilot-Scale Horizontal Subsurface Flow Constructed Wetlands for Wastewater Treatment النص الكامل
2023
Kumar Swarnakar, Arvind | Bajpai, Samir | Ahmad, Ishtiyaq
Constructed wetland systems (CWs) are low-cost natural treatment systems for various types of influents. Although mainly the natural wetlands are soil-based, the constructed wetlands have been traditionally built using aggregate media. The performance of four types of available soils in Chhattisgarh was studied as the filter media in the horizontal subsurface flow-constructed wetland (HSFCW). Fourteen pilot-scale CW units with different soil types (entisol, vertisol, alfisol, inceptisol, and stone aggregate) and plant types (Canna indica and Typha latifolia) were used to treat domestic wastewater (WW). One set of each soil base reactor was planted with Canna indica and Typha latifolia, and one was kept blank (unplanted). All soils and plants are easily available.The reactors received primary wastewater in batch loads with WW loading for six hours to maintain aerobic conditions. The residence time of WW was 48 hours, and the applied hydraulic loading rate (HLR) was based on soil and aggregate. According to the findings, the planted HSFCW was more effective than the unplanted system. The results show that the wetland constructed on the treatment efficiency of the soil base has excellent potential to treat WW, with both plants.
اظهر المزيد [+] اقل [-]Forecasting and Seasonal Investigation of PM10 Concentration Trend: a Time Series and Trend Analysis Study in Tehran النص الكامل
2023
Pardakhti, Alireza | Baheeraei, Hosein | Dehhaghi, Sam
In this study, a multitude of statistical tools were used to examine PM10 concentration trends and their seasonal behavior from 2015 to 2021 in Tehran. The results of the integrated analysis have led to a better understanding of current PM10 trends which may be useful for future management policies. The Kruskal – Wallis test indicated the significant impact of atmospheric phenomena on the seasonal fluctuations of PM10. The seasonal decomposition of PM10 time series was conducted for better analysis of trends and seasonal oscillations. The seasonal Mann-Kendall test illustrated the significant possibility of a monotonic seasonal trend of PM10 (p = 0.026) while showing its negative slope simultaneously (Sen = -1.496). The forecasting procedure of PM10 until 2024 comprised 15 time series models which were validated by means of 8 statistical criteria. The model validation results indicated that ARIMA (0,1,2) was the most satisfactory case for predicting the future trend of PM10. This model estimated the concentration of PM10 to reach approximately 79.04 (µg/m3) by the end of 2023 with a 95% confidence interval of 51.38 – 107.42 (µg/m3). Overall, it was concluded that the use of the aforementioned analytical tools may help decision-makers gain a better insight into future forecasts of ambient airborne particulate matter.
اظهر المزيد [+] اقل [-]Status, Health Effects and Remediation Techniques of E-waste – A Review النص الكامل
2023
Guin, Shailu | Deswal, Surinder
The annual global generation of e-waste is estimated to be 59.08 million tonnes (7.37 kg per capita), out of which the major chunk is being processed in informal sector using primitive and hazardous methods in developing countries due to cheap labour, less stringent laws and regulatory policies. Despite the fact the annual global value of e-waste industry being about USD 62.5 billion that provides employment to millions in developing countries, the unstructured/informal operations in e-waste sector had and have been causing hazardous health issues in human and environment along with unlawful activities. Many studies have been reported on wide array of interrelated aspects and issues of e-waste, but only few studies have reviewed potential remediation techniques that can take care of the increasing e-waste and its sustainable management. Therefore, disposal and remediation techniques for polluted sites have been the key concerns in the field of environmentally sustainable management (ESM) of e-waste. The present review revealed that of all the classic and hybrid remediation techniques, the biological remediation techniques being eco-friendly and cost effective needs to be explored for metal removing from contaminated environment. The review also concludes the imminent necessity of ESM by framing and implementing regulations and laws essentially incorporating Extended Producer Responsibility (EPR) in developing countries. The review of Indian scenario suggests the scope of startups for the sustainable recycling of e-waste to achieve healthy environment, employment and economic opportunities.
اظهر المزيد [+] اقل [-]Treatment of Fish Processing Wastewater by Alum and PAM: A Comparative Study on Turbidity, COD, BOD, and Rheological Properties النص الكامل
2023
AL Riyami, Hanan Ahmed Said | Al Dawery, Salam Kadhim | Reddy, Sreedhar | Ahmed, Anwar
This research article compares the efficacy of using alum and poly aluminum chloride (PAM) for the treatment of fish processing wastewater. This study aims to determine the effectiveness of each treatment method in reducing turbidity, COD), BOD, and altering the rheological properties of the wastewater. Batch mode coagulation and flocculation experiments were conducted using lab scale jar test apparatus. The findings indicate that both alum and PAM can significantly reduce turbidity and COD. The highest turbidity removal efficiency of 93% was achieved with alum at a dose of 200 mg/L, while PAM achieved a maximum turbidity removal efficiency of 86% at a dose of 100 mg/L. Alum and PAM achieved the highest BOD5 and COD removal efficiencies at a dosage of 200 mg/L and pH 7.0. However, the removal efficiencies varied at different pH values and dosages. Alum and PAM have significant effect on the rheological properties of fish processing wastewater. The viscosity of settled residual sludge after chemical coagulation is more compared to untreated fish processing wastewater due to aggregation of suspended particles to form larger flocs. This would improve the settling properties of the coagulated sludge. The study concludes that both alum and PAM can be viable options for treating fish processing wastewater, with Alum showing a slight edge over PAM in certain aspects.
اظهر المزيد [+] اقل [-]Catalytic Conversion of Carbon Dioxide by Metal-Organic Frameworks: an Effective Approach for CO2 Utilization النص الكامل
2023
Tayebi, Leila | Rahimi, Rahmatollah | Akbarzadeh, Ali Reza
Due to the increase in carbon dioxide emission, there is a need for achieving efficient ways to reduce CO2 harmful effects. There are several strategies to mitigate atmospheric CO2 concentration. The catalytic cycloaddition of carbon dioxide with epoxides to provide cyclic carbonates employing metal-organic frameworks is a promising method for this purpose. Herein the application of two porous porphyrinic MOFs (Co-PMOF and Cu-PMOF) as catalysts in CO2 conversion was investigated. These MOFs demonstrated good crystallinity and porosity, providing them with two promising platforms to study CO2 conversion reactions. These heterogeneous porphyrin-based MOFs are catalytically efficient towards the chemical conversion of CO2 under moderate conditions because these MOF matrices contain a high density of active Lewis acidic and basic sites for activating CO2 and epoxide compounds. These MOFs exhibited high catalytic efficiency for the chemical fixation of CO2 at ambient temperature and solvent-free conditions. The reactions formed the proportionate cyclic carbonates in good yields. These products are valuable compounds in a variety of chemical fields.
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