Research Article
Spatial Distribution of Air Quality in Narayanganj District Town, Bangladesh
Issue:
Volume 14, Issue 2, April 2025
Pages:
21-35
Received:
30 September 2024
Accepted:
30 December 2024
Published:
7 March 2025
DOI:
10.11648/j.ajep.20251402.11
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Abstract: Globally air pollution is a major concern as it poses serious health risks, damages the environment, contributes to climate change, and incurs substantial economic costs. The objective of this study is to monitor the Particulate Matters (PM1, PM2.5, and PM10) and Carbon Monoxide (CO) concentration based on different land use in Narayanganj District town. This study was conducted in seven land uses, 60 locations of Narayanganj District, a district of Dhaka Division; by using portable Air Quality Monitor, Indoor Outdoor Formaldehyde (HCHO) Detector (Model: DM106) and CO Meter (Model: AS8700A). Descriptive statistics and whisker box plots were also employed to analyze and visualize the variations in pollutant concentrations across different locations. Additionally, a dendrogram plot was created to classify and interpret data clusters, providing a deeper understanding of the spatial distribution of pollutants. Results indicated that the average concentration of PM2.5 of different land-use were found 3.37 times higher than the Bangladesh National Ambient Air Quality Standard (NAAQS) level. NAAQS set for PM2.5, and PM10 at 65 and 150 µg/m3, respectively by Department of Environment (DoE). Consequently, the most polluted location was found in Industrial location with PM1, PM2.5 and PM10 concentration of 230, 389 and 496 µg/m3, respectively. Also, the concentration of CO was 1.3 to 2.3 times higher than NAAQS level which is 9 ppm (8-hour) set By Department of Environment (DoE). Besides, the study estimated that the average PM2.5/PM10 ratio was 77.32%, while the PM1/PM2.5 ratio was 60.85%, which indicated significant presence of finer particles in the air. Therefore, the study underscores the urgent need for enhanced air quality policies and public awareness in Narayanganj District due to critically high levels of air pollution.
Abstract: Globally air pollution is a major concern as it poses serious health risks, damages the environment, contributes to climate change, and incurs substantial economic costs. The objective of this study is to monitor the Particulate Matters (PM1, PM2.5, and PM10) and Carbon Monoxide (CO) concentration based on different land use in Narayanganj District...
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Research Article
Density-Based Multi-Stage Flotation Sorting of Microplastics in Beach Sand
Md Ariful Islam,
Shamim AL Mamun
,
Hiroshi Asakura*
Issue:
Volume 14, Issue 2, April 2025
Pages:
36-49
Received:
6 March 2025
Accepted:
27 March 2025
Published:
17 April 2025
DOI:
10.11648/j.ajep.20251402.12
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Abstract: Microplastics (MPs) are ubiquitous in the environment and pose an increasing concern for the world’s terrestrial and marine ecosystems due to their persistence and potential toxicity. Density sorting of MPs in beach sand, combined with heat treatment to remove impurities such as wood fragments, enhances the analysis of MP contamination. While density sorting does not identify the composition of MPs, it provides insight into their sources and potential for re-drift into the ocean. In this study, we evaluated the accuracy of a multi-stage Flotation sorting technique in separating MPs based on their density in beach sand. A major challenge in density sorting is interference from impurities such as wood fragments. To address this, heat treatment is performed to remove wood fragments. We also evaluated the effects of heat treatment on the density and weight of MPs. The findings indicate that most MPs experienced a density change and a weight loss of less than 4% and 1%, respectively, suggesting the minimal effects of the heat treatment. However, certain types of MPs, such as those containing voids (e.g., PVC-NS), showed significant density changes, which impacted their sorting behavior, resulting in some misclassification during the flotation sorting. Unless the heat treatment caused a density change, the multi-stage Flotation sorting method, including water and saturated calcium chloride (SCC) solutions, achieved high recovery rates (90%-110%) for light MPs, heavy MPs, and wood and sand mixtures. In other words, light and heavy MPs and the wood and sand mixture were separated without misjudgment and loss. Overall, this study confirms the feasibility and efficiency of multi-stage flotation sorting for MP analysis in beach sand and highlights the need to carefully consider heat treatment effects in future environmental studies on MPs.
Abstract: Microplastics (MPs) are ubiquitous in the environment and pose an increasing concern for the world’s terrestrial and marine ecosystems due to their persistence and potential toxicity. Density sorting of MPs in beach sand, combined with heat treatment to remove impurities such as wood fragments, enhances the analysis of MP contamination. While densi...
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Research Article
Corn Cob-Derived Activated Carbons for Gold Mine Wastewater Treatment in East Cameroon
Issue:
Volume 14, Issue 2, April 2025
Pages:
50-67
Received:
24 February 2025
Accepted:
13 March 2025
Published:
17 April 2025
DOI:
10.11648/j.ajep.20251402.13
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Abstract: In East Cameroon, the discharge of untreated effluents, from gold recovery and concentration, into nature poses serious environmental problems. The main aim of this study was to investigate the efficiency of three corn cob-derived activated carbons for gold mine wastewater treatment of East Cameroon. Wastewater samples were collected in three mining sites (Kambele 1, Kambele 2 and Dem) for laboratory analysis. The three activated carbons were produced by chemical and thermal activation with three different chemical reagents (ZnCl2, NaOH, and KH2PO4, respectively) meanwhile Al2(SO4)3 served as the control. The main results revealed that wastewater from Kambele 2 area was the most contaminated with highest proportion of Fe (3.52 mg/l), Hg (62.7 mg/l), Cd (533.95 mg/l), NO3- (103.33 mg/l), SO42- (640 mg/l), HCO3- (152.5 mg/l), Ca2+(447.12 mg/l), Na+ (26.8 mg/l), Mg2+ (32 mg/l), K+ (51.05 mg/l). And with low proportion of Ni (0.21 mg/l), Pb (0.41 mg/l), PO4 (0 mg/l), and Mn (5.66 mg/l), as compared to wastewater from the other sites. Wastewater samples from this site were used to test the efficient of ACs. The wastewater was greatly improved with ACZnCl2 and ACNaOH, but ACNaOH performed better than the control and other activated carbons for cationic extraction, and was the only AC to adsorb almost 100 % of Hg in wastewater. The ACZnCl2 (0.5 mm particle size) was the most efficient in the extraction of major anions: NO3- (96.60 %), SO42- (81.25 %), HCO3- (76 %), compared to the Ca(OH)2 and Al2(SO4)3 (control) and ACNaOH. Generally, the ACZnCl2 (0.5 mm particle size) was more efficient compared to ACKH2PO4 and ACNaOH in adsorption of Fe (94.05 %), Mn (88.51 %), and Ni (99.99 %). The Al2(SO4)3 was the only one that reduced the concentration of Pb (24.39 %) and was good for extraction of NO3- (96.6 %), Fe (92.6 %), Mn (88.51 %), and Ni (99.99 %). From ACZnCl2, the smaller the particle size of cob-derived AC, the better the extraction of heavy metals and anions and the poorer the extraction of cations (Ca2+, Na+, Mg2+, K+). The economic analysis of the different methods enabled to note an additional profit rate of 60 to 160% with the use of the ACs compared to Al2(SO4)3. Thus, ACZnCl2 and ACNaOH can either be used alone or combined with Al2(SO4)3 for best performance to reduce cost and optimize contaminant removal.
Abstract: In East Cameroon, the discharge of untreated effluents, from gold recovery and concentration, into nature poses serious environmental problems. The main aim of this study was to investigate the efficiency of three corn cob-derived activated carbons for gold mine wastewater treatment of East Cameroon. Wastewater samples were collected in three minin...
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