Environmental Nanotechnology, Monitoring and Management最新文献

The green chemistry approach was unitized for the development of fluorescent nanomaterial. The objective of this study is to develop plant-based fluorescence nanomaterials via environment-friendly and biocompatible approach. Here, water-soluble yellow emissive gold nanoclusters were synthesized by using extract of Senna auriculata leaves and 1.25 mM of HAuCl₄·xH₂O via microwave-assisted method. Senna auriculata-AuNCs (S. auriculata-AuNCs) exhibit excellent solubility, good quantum yield (QY), stability, and biocompatibility. The ultra-small (<5 nm) size of S. auriculata-AuNCs displayed yellow emission and were characterized by using fluorescence, UV–visible, FT-IR, HR-TEM, zeta potential, DLS, XPS, and XRD techniques. S. auriculata-AuNCs display an intense emission of 620 nm when excited at 500 nm. The as-synthesized S. auriculata-AuNCs act as an effective sensor for sensing glyphosate pesticide via the “turn-off” mechanism. Moreover, S. auriculata-AuNCs showed a good performance in detecting glyphosate with a wider linear range from 0.05 to 100 µM, offering the detection limit of 32.0 nM for glyphosate. Additionally, S. auriculata-AuNCs are also able to visualize Saccharomyces cerevisiae cells, and successfully applied in assaying glyphosate pesticide in apple, rice, river, and canal water samples.

One of the most common endocrine-disrupting compounds (EDCs) in the environment is bisphenol A (BPA). BPA-based products are becoming more prevalent worldwide. The contamination of BPA can exist in food, drinks, soil, dust, air, soil, and wastewater. BPA can enter the body through various including the respiratory, digestive, and dermal tract routes. Exposure to BPA has been linked to chronic diseases, including obesity, diabetes, and cardiovascular and liver diseases. Although maximum concentrations of BPA in drinking water varied across regions between 0.014 μg/L, 6.4 μg/L, and 1.9 μg/L and 5.1 μg/L in groundwater and surface water, respectively, due to the efficiency of the treatment plants helped in reducing BPA levels in drinking water. However, Adsorption is considered a significant technique for BPA removal due to its considerable influence on toxicity, bioavailability, and transport of heavy metals. The adsorption technique achieves 99 % removal efficiency for BPA. Meanwhile, green nanoparticle characteristics offer the best possibility to eliminate persistent contaminants, including BPA, via an adsorption mechanism due to their excellent adsorptive capabilities. Plants, bacteria, algae, and fungi can all be used for the green synthesis of NPs. Plant extracts offer a cheap and environmentally friendly solution to synthesizing without using intermediates. A comprehensive review of bisphenol A sources, occurrence, effects, and treatment methodologies is presented in this review article. In addition, the utilization of nanoparticles for BPA elimination is also discussed. The literature indicates that synthesizing green nanoparticles is a simple yet highly efficient technique to enhance nanoparticle properties for BPA removal, which can reach up to 96 % efficiency. Applying green nanoparticles in water treatment to remove BPA reduces energy consumption, eliminates chemical use, and generates environmentally friendly products.

The presence of microorganisms and inorganic pollutants in water bodies results in adverse effects on nature as well as human health. In this study, clay-based adsorbents were used for the removal of phosphates and Escherichia coli bacteria. Two samples, Na-Zr-50-2.5 and Na-Zr-50-5, were prepared using 2.5 and 5 mmol of zirconium per gram of clay. The former material has shown better Langmuir phosphate adsorption capacity (∼11.5 mg P/g) at pH 4. Chitosan modification was applied to Na-Zr-50-2.5 to improve its performance at higher pH. Post modification, the maximum adsorption attained at pH 4 was 14.5 mg P/g, and it improved from 8.3 to 11.8 mg P/g at pH 7. The possible major governing mechanism responsible for the adsorption of phosphates was the formation of inner-sphere complexes. Application of Na-Zr-50-2.5 was also explored for removing E. coli cells from aqueous saline solution. The E. coli removal efficiency of this sample was found to be 62.64 %. This study reveals that modified clays effectively reduce the phosphate and E. coli levels in aqueous solution and can be proved as environment-friendly, low-budget adsorbent materials in wastewater treatment.

Zinc oxide (ZnO) has long been considered a great potential candidate in a variety of applications in photocatalysis. However, zinc oxide poses various drawbacks such as fast recombination of photogenerated charges and inability to catalyze under visible light excitation, which hinders further applications, therefore, modifications are highly required to tackle such. This review aims to shed light onto the basic and the influences of the modification routes namely on the photocatalytic activity of the treated zinc oxide materials. The methods of elemental doping and heterojunction construction are covered, including type, methodology, and comparative effects. Moreover, the current advances in the photo-activity of ZnO and its derivatives are also reported to provide an overview of the potential applications of zinc oxide-based materials. Aspects discussed including hydrogen production, organic photocatalysis, and energy generation. In addition, the review also briefly discusses the mechanism behind such aspects. Recently published results are provided and compared to reveal the applicability of ZnO on a real-life scale as the photocatalyst. In the end, future perspectives are provided for the aid in future study of photocatalysis as well as its potent application.

A quantification of phthalate acid esters (PAEs) concentrations was performed on sediment and fish samples collected from industrial, urban, and rural regions along the Persian Gulf coastline from November 2020 to March 2021. The results indicated that the mean concentrations of ƩPAEs in sediment samples from urban, industrial, and rural regions were 1486, 855, and 257 ng/g, respectively. In fish samples, the corresponding values were 392, 284, and 62.4 ng/g. The mean concentrations of ƩPAEs in sediment/fish samples from urban and industrial areas were significantly higher (P < 0.05) than in rural areas. DEHP had the highest level and detection frequency (DF = 100 %) of the PAEs congeners studied. The DEHP concentrations in sediment samples from the Urban, Industrial, and Rural regions were 283 ± 37.5, 219 ± 15.7, and 44.9 ± 19.5 ng/g, respectively, while in fish samples, they were 904 ± 272, 564 ± 60.5, and 146 ± 43.5 ng/g, respectively. The results of the ecotoxicological effects assessment also revealed that the Persian Gulf coasts are significantly contaminated with PAEs, which may have substantial effects on the aquatic ecosystem of the region (including the composition of aquaculture communities, enzymatic processes, and marine culture microorganisms). As a result, there is an urgent need for decision-makers and policymakers to enact laws that prohibit the discharge of PAEs-containing waste into the Persian Gulf coasts to protect the marine ecosystem.

The deteriorating water quality and increasing pollution of Lake Victoria, Africa’s most important and world’s second-largest freshwater lake, is threatening the critical resource within East Africa, which has profound ecological and socio-economic significance. This comprehensive review investigates the environmental dynamics of the lake, exploring temporal trends in water quality, heavy metals, microplastics, and emerging organic pollutants in Kenyan, Tanzanian, and Ugandan waters. Assessing the period from January 2000 to December 2022, the analysis integrates research findings from Lake Victoria and its basin. A complex interaction between natural processes and human activity causes fluctuations in the water quality of Lake Victoria. The study reveals substantial variations in key parameters, reflecting the impacts of industrial discharges, agricultural practices, urbanization, and wastewater inputs. Noteworthy among these variations are heavy metal concentrations, with lead consistently surpassing the acceptable levels in Kenyan and Ugandan waters. Zinc concentrations showed varying patterns, and chromium levels in sediments raise concerns by surpassing EPA guidelines in specific locations. The investigation of organic pollutants identified over 170 contaminants, highlighting the dominance of dichlorodiphenyltrichloroethane (DDT) and its derivatives. Microplastics, recognized in the guts of vital fish species and surface water, merge as a growing concern, posing risks to the aquatic ecosystem. This review illuminates the nature of pollutants in Lake Victoria and identifies knowledge gaps in research attention, especially in the northwestern, western, and southwestern lake basins, and the islands of Lake Victoria, overlooked for more than two decades. Scrutinizing existing research, it serves as a compass, pointing towards areas necessitating further investigation and thereby charting future directions in the research community.

Surface sediments form an integral component of freshwater ecosystems and they are a major sink-and-source for toxic pollutants, providing a reliable indication of a water body’s integrity. Distinct freshwater sediment investigations have informed the conclusions made about the ecological and pollution status of aquatic systems worldwide, but a widespread evaluation of the global status of freshwater sediments is lacking. From our perspective, an extensive environmental analysis of the available published data can address this need and improve our wholesome understanding of toxic metal impacts on global freshwater systems. Thus, surface sediment metal data collected from 149 freshwater sites in 32 countries were systematically analyzed using standard environmental indices (e.g. geoaccumulation index, modified hazard quotient, enrichment factor, etc.) and multivariate statistical methods (MSA). Average concentrations of all the metals except cobalt and zinc exceeded the recommended limits. Arsenic, cadmium, and mercury registered the highest frequency of severe pollution impacts on 29 – 69 % of the sites. 4 to 31 % of the studied sites recorded considerable to severe aquatic biota risk majorly from arsenic, cadmium, chromium, and nickel while 65 % of the sites recorded severe ecological risk (CSI > 5, RI ∼ 600). A high linear correlation with low ordination stress (R² = 0.93, Stress = 0.023) from non-metric multidimensional scaling agreed with the Pearson correlation analysis results, while principal component analysis revealed four major components that explained 89 % of the data variance. Source enrichment investigation indicates that pollution is a result of geogenic and anthropogenic contributions. The common anthropogenic sources among study sites include industrial and municipal wastewater and sewage, agriculture, surface runoff, fossil fuel emissions, and mining activities. The study can serve as a reference for future pollution studies, create extensive awareness of the dire ecological status of freshwater systems, and ultimately elicit site-specific remediation and mitigation action plans from policymakers.

Sewage treatment plants (STP) were known to play an essential role in removing organic matter from domestic wastewater, aligning with Sustainable Development Goal (SDG) 6 regarding clean water and sanitation. Despite their importance, STP performance could decline, leading to failure in fulfilling the established standards. This study addresses the decline in treated domestic wastewater quality observed in a bottled water factory in North Sumatra, Indonesia, where the system experienced setbacks leading to poor COD degradation performance, and the pH parameter declined to a low of 4.78 at the outlet tank. Not only does this study aim to fix the quality decline that occurred, but it also describes the application of the DMAIC framework in addressing this matter, which makes this study distinct from the others. Utilizing a root cause analysis within the DMAIC framework, we identified unhealthy activated sludge conditions as the primary cause. Corrective actions, including re-seeding and aeration adjustments, were conducted to enhance and stabilize the pH and COD parameters. Additionally, the disinfection process in the effluent tank was found to be essential for maintaining compliance with quality standards. This research contributes to a better understanding of STP management and the benefits of DMAIC implementation in addressing the problem while underscoring the importance of STP management in achieving SDG 6.

Vegetable oil refinery wastewater (VORW) is a significant source of refractory pollutants necessitating efficient treatment prior to discharge. This study investigates the treatment of VORW via coagulation-flocculation using ferric chloride (FeCl₃) as a coagulant and chitosan as a natural flocculant. Central Composite Design (CCD) is employed to optimize the treatment process and assess the interplay of experimental factors. The study evaluates turbidity, COD, and polyphenols as responses, with pH, FeCl₃ concentration, chitosan dosage, and agitation time as independent factors.

The results showed that the optimal conditions identified include pH 6, FeCl3 dosage of 1.6 g/L, chitosan dosage of 13.4 mg/L, and agitation time of 26 min, resulting in 100 % turbidity removal, 86 % COD reduction, and 90 % polyphenol removal. The analysis of variance indicated that the established models were significant and that they are characterized by a good fit (R² in the order of 0.95, 0.96, and 0.96 for turbidity, COD, and polyphenols, respectively).

These findings highlight the efficacy and sustainability of the coagulation-flocculation process with chitosan, offering a practical, rapid, and cost-effective solution for VORW treatment and environmental preservation.

Monitoring the nutrient levels of the dam water on the Bui hydropower project (Ghana) is vital for understanding its ecological health. The purpose of this study is to evaluate current (2021) nutrient levels and examine the irrigational water quality. The novelty of this research lies in the combination of nutrient analysis and irrigational water quality index (IWQI) as tool to understand the ecological health of the dam water. Bui dam water is slightly acidic (pH of 6.6) which partly influences nutrient bioavailability in the dam water. The composition of water in terms of ion dominance follow the order of ${Ca}^{2+}>{Na}^{+}>{Mg}^{2+}>K^{+}$ and that of anions followed the order of ${HCO}_3^{-}>{Cl}^{-}>{SO}_4^{2-}>{NO}_3^{-}$, with signatures of Ca²⁺- Mg²⁺- HCO₃^– water type. Pearson’s correlation plot shows pH, TDS, and EC influences sulphate distribution in the dam. EC mean level of 78.06 µS/cm is below acceptable ranges (150 and 500 µS/cm) known to sustain freshwater fish species (e.g., Alestidae, Anabantidae and Bagridae family) present in the Bui dam. Historical nitrate, phosphate and sulphate measured ${2.01mgL}^{-1}$, ${0.16mgL}^{-1}$ and ${20.96mgL}^{-1}$ as against ${0.79mgL}^{-1}$, ${0.60mgL}^{-1}$ and ${2.22mgL}^{-1}$ caused by the impoundment. The nutrient decrease shows improved