Environmental Nanotechnology, Monitoring and Management最新文献

In the pursuit of efficient and cost-effective textile wastewater treatment, this study compares the performance of titanium and aluminium electrodes in electrocoagulation (EC). Titanium electrodes, renowned for their high corrosion resistance, demonstrated superior colour removal efficiency (CRE) at 98.5 % under optimised conditions 10-minute reaction time and 18 Am⁻² current density. Conversely, aluminium electrodes, while effective, required extended reaction times and higher current densities, achieving a CRE of 97.8 %. The cost analysis favoured titanium electrodes at 2.86 ₹/m3, compared to 51.13 ₹/m3 for aluminium. For safe reuse, treated effluent subjected to activated carbon (AC) filtration, showcasing remarkable dye and metal ion removal efficiencies. The AC filtration proved exceptionally effective, as evident in the ICP-OES results. Post-EC, titanium concentration exceeded limits but was efficiently reduced to 0.001 mg/L after AC treatment, while aluminium concentration decreased significantly. Chemical oxygen demand (COD) and biological oxygen demand (BOD) removal efficiencies were compared, with titanium electrodes achieving 100 % COD and 62 % BOD removal and aluminium electrodes at 94 % COD and 47 % BOD removal. Comprehensive analytical techniques, including XPS, SEM, EDAX, FTIR, mass spectroscopy, HPLC, and ICP-OES, enhance our understanding of EC and AC mechanisms. The combined EC and AC process not only enhanced water quality but also proved environmentally sustainable, providing an eco-friendly solution for small-scale textile industries in need of efficient effluent treatment.

Globally acephate (an organophosphate pesticide) contaminates water bodies, and detriment to the biota is cancer-causing and neurotoxic which needs to be safely removed. This study presents the synthesis and characterization of magnetic montmorillonite (Fe₃O₄-MMT) as an adsorbent for the adsorption of acephate. The features and characteristics of the nanocomposite were traced by XRD, SEM-EDX, gas sorption analysis, FTIR, and XRF. RSM techniques were used to identify the optimal process variables that result in the highest removal. The numerical optimization of optimum variables corresponds to an initial acephate concentration of 2 mg/L, pH 6 and material adsorbent dose of 0.5 g/L. The uptake of acephate achieved 83.18 % under optimum environs. Dual factors i.e., concentration and dosage remarked as vital parameters that affected the response from ANOVA. Results revealed that equilibrium adsorption data were best fitted with Langmuir and kinetic data were well described by pseudo-first order kinetic model. Thermodynamic parameters such as enthalpy, entropy and Gibb’s energy were evaluated and the effect of temperature on acephate adsorption was studied. Greater acephate adsorption onto on Fe₃O₄ serves as an excellent material for pesticide mitigation.

Industrial discharge of organic pollutants poses a severe threat to human health and aquatic life. Elimination of these pollutants from drinking and wastewater is imperative for a sustainable environment. To address this issue, pure and Ce³⁺-doped TiO₂ nanoparticles are designed with stable tetragonal (anatase) lattices by a low-temperature sol–gel process. The spectroscopic and structural analyses reveal the formation of TiO₂ and Ce-TiO₂ nanocrystals with controlled crystallite size (3–6 nm), high surface areas, and varying surface chemistry. The effect of calcination (thermal (Δ) treatment at 450 °C) on the structure and photocatalytic performance of ΔTiO₂ and ΔCe-TiO₂ nanoparticles is also investigated. Simultaneous photocatalysis experiments over a 90-min exposure to natural sunlight show 240 % and 191 % improved elimination of methylene blue (MB), an organic pollutant, by Ce-TiO₂ and ΔCe-TiO₂ nanoparticles compared to their pure TiO₂ analogs. Also, Ce-TiO₂ and ΔCe-TiO₂ nanoparticles exhibit 326 % and 229 % faster kinetics for the photocatalytic elimination of MB primarily due to the surface-confinement of Ce³⁺ in Ce-TiO₂ nanocrystals, where Ce³⁺ ions play a dual role as reducing agent for adsorbed oxygen species and electron trap sites via Ce³⁺/Ce⁴⁺ interconversion. The mechanism of photocatalytic redox reactions is discussed. The study elaborates on the role of Ce-TiO₂ nanoparticles as an effective photocatalyst for the elimination of organic pollutants in wastewater.

This study aims to demonstrate a cost-effective, efficient, and chemical-free solution for rapid wastewater treatment processes. The Nile's and drainage water, were used to isolate and identify 146 presumptive Escherichia coli strains. It was found that 73.9 % of these strains were verified using 16S‐rDNA. Coliphages, specifically three new phages (MCn10/MCn11/MCn12), were found in all sampled sites, with the highest levels at drain outfalls. The Siphovirus MCn10, Myoirus MCn11, and Podovirus MCn12 as recognized using morphological and molecular analysis have exhibited different burst sizes, with 95, 100, and 70 plaque-forming units (pfu) per infected cell with latent periods 35, 40, and 60 min, respectively. These phages show a remarkable ability to inhibit the growth of seven diverse bacterial strains under neutral conditions, highlighting their polyvalence. The removal efficiency (%) of Escherichia coli colonies reached 95.2 %, while for Citrobacter freundii it was 91 %, Proteus vulgaris 73.3 %, Salmonella sp. 98 %, Pseudomonas aeruginosa 50 %, Pseudomonas fluorescens 80 % and Enterococcus faecalis 96.1 %. Significant improvements were observed in the physicochemical parameters of treated wastewater with polyvalent phage mix. The treatment process demonstrated an average increase rate of (69.1 %) in dissolved oxygen (DO), while the average reduction rate in total dissolved solids (TDS) (59.46 %), turbidity (57.15 %), chemical oxygen demand (COD) (58.75 %), ammonia (NH₃) (70.4 %), electrical conductivity (EC) (60.91 %), nitrate (NO₃^–) (60.1 %), and biochemical oxygen demand (BOD) (65.45 %) compared to untreated wastewater. The quality of the treated wastewater gradually increased and reached its peak after 12 h, indicating a nearly 100 % improvement after beginning inoculation with the phage mix. This investigation presents a novel candidate for polyvalent phages that can be safely produced with non-pathogenic production hosts. This technology is an innovative development in wastewater reuse management and reduces the risk of unexpected pathogen leakage which may offer significant economic gains.

Zinc oxide (ZnO) and copper-doped zinc oxide (ZnO:Cu) nanopowders were synthesized via solvothermal methods using methanol and hexamethylenetetramine (HMTA). Undoped ZnO nanopowders underwent calcination in O₂-rich and H₂-rich atmospheres at 600 °C. Samples were studied by scanning electron microscopy, Brunauer–Emmett–Teller (BET) surface area analysis, X-ray diffraction (XRD), and Raman, photoluminescence (PL) and UV–vis absorbance spectroscopies. The doping and calcinations led to a reduction of the optical bandgap of the nanopowders, while their structure remained hexagonal wurtzite with some changes in lattice parameters and average nanoparticle sizes. The Cu²⁺ doping led to a BET surface area and violet PL component increase. Samples were also examined for environmental related applications, namely as photocatalyzers for dye degradation and as ethanol optical sensors. For photocatalytic activity in methylene blue degradation under UV, H₂-rich calcined powders excelled, with a rate constant of −0.076 min⁻¹, surpassing −0.057 min⁻¹ (ZnO:Cu), −0.056 min⁻¹ (O₂-rich calcination), and −0.041 min⁻¹ (as-grown ZnO). We propose that this improvement can be attributed to the formation of ZnO/Zn interfaces stemming from the reduction of surface interstitial zinc by H₂ during calcination, in addition to the observed reduction of the ZnO bandgap. The doped nanopowders PL also showed excellent response when exposed to ethanol vapor.

Industrial activities have surged in recent years, resulting in severe environmental and human health consequences. Coal mining, in particular, has emerged as a major contributor to environmental degradation, notably through water pollution. Acid Mine Drainage (AMD) refers to the contaminated water generated by mining operations, characterized by low pH levels and high concentrations of heavy metals. Given the substantial impact of AMD on the environment, the development of effective treatment methods is imperative. This review aims to provide a comprehensive and in-depth understanding of AMD treatment, with a specific emphasis on hybrid technologies. To the best of our knowledge, this review represents the first systematic attempt to explore the application of hybrid technologies for AMD treatment. The mapping and PRISMA 2020 methodology were employed to ensure a thorough and comprehensive analysis of the available literature. This paper extensively examines the physicochemical characteristics of AMD, elucidating both individual treatment methods and the emerging field of hybrid treatment approaches. Furthermore, meticulous performance evaluations of each method are conducted, shedding light on the existing challenges and future research prospects in this domain. By addressing the current gaps in our understanding of hybrid technologies for AMD treatment, this paper makes a significant contribution to the existing body of knowledge. The findings presented here offer valuable insights into the development of efficient and sustainable treatment strategies for AMD. Ultimately, this review serves as a valuable resource for researchers, practitioners, and policymakers seeking to mitigate the adverse effects of AMD and promote environmental stewardship in mining operations.

The adsorption of cationic dyes is more significant in the binary system compared to the simple system, making it a crucial element in the study of complex matrices. Experimental and theoretical investigations were conducted on the adsorption of two cationic dyes, Malachite Green (MG) and Safranin (SAF), on activated carbon derived from walnut shells (AC-Ws) in both simple and binary systems. The impact of pH and the volume of adsorbent in the two systems were exclusively examined. The electrophilic potency of the dyes influenced elimination efficiency. According to the theoretical analysis, MG proves to be more electrophilic than SAF, and therefore displays greater interaction with surface sites in both simple and binary systems, resulting in removal rates of 93.12% and 78.41%, correspondingly. Best removal results were achieved at pH 7 for both systems. The Langmuir model is the most fitting method to explain the removal of dyes, both in simple and binary systems. According to the results of the kinetic study, the phenomenon obeys the pseudo-second order. The theoretical and experimental studies are in alignment, and it can be deduced that the decrease in the elimination efficiency of SAF in the binary system is due to the decreased acceptance of electrons when SAF is present.

Due to industrial, commercial, and human activities, water pollution or contamination has become a stern environmental threat affecting all the living species. Consequently, efficient water pollution treatment technologies have been focused due to increasing global demands of clean water. Among various purification methodologies, competent adsorption processes via adsorbent materials have gained research interest. Graphene quantum dots are tiny spherical carbon nanoparticles having enormous technical potential owing to unique fluorescence, quantum, and electronic features. Characters of quantum dots have been further enhanced thru modification and nanocomposite formation. Accordingly, design, microstructure, robustness, and essential structural and physical features of graphene quantum dots derived nanomaterials have been foreseen in literature. This up-to-date overview highpoints the fabrication methodologies, attained features, and technical adsorption potential of graphene quantum dot, modified graphene quantum dot and resulting nanocomposites. Due to high surface area and specific physical/applied properties, graphene quantum dots have revealed fine potential towards the adsorption of hazardous water pollutants including dyes, toxic metal ions, and noxious heavy metal ions. Henceforth, graphene quantum dot derived nanocomposite adsorbents having high adsorption rate, capacities, and efficiencies have brought about numerous revolts in the fields of adsorption towards water treatment. Future research efforts on quantum dots adsorbents may resolve the challenges of efficient water treatment for industrial applications.

Mangrove forests are unique and invaluable ecosystems due to their role in biodiversity, coastal protection, and carbon sequestration. This study examined spatial variability of selected physicochemical parameters of mangrove soil and species distribution at the Negombo lagoon. Eighteen sampling sites were selected based on judgmental sampling techniques. A 10 m x 10 m area was selected within the 1 km x 1 km grid to get the replicate soil samples from 0 − 15, 15–30 and 30–45 cm depths from the surface. Further, a vegetation survey was conducted to identify mangrove species in the same 10 m x 10 m area. Soil temperature, pH, salinity, and soil organic matter (OM) were analyzed using standard laboratory methods. Results show that temperature varied spatially from 25.2 °C to 30.0 °C, with the highest temperature recorded in the topsoil layer. Soil pH and salinity spatially varied from 5.39 to 8.31 and 0.56 % to 8.83 %, respectively. Soil organic matter spatially varied from 2.56 % to 15.7 % and increased with the increasing depth. Soils with high salinity tend to reduce OM by accelerating the mineralization of OM. Correlation analysis showed a positive relationship between salinity and OM (r = 0.57; P < 0.05). Rhizophora apiculata, Rhizophora mucronate and Avicennia marina were associated more in soils with high salinity (3.72 % − 7.15 %) and neutral to weakly alkaline pH. Bruguiera gymnorrhiza was more prevalent in soils with higher salinity (7.69 % − 8.83 %) and lower pH, while Lumnitzera racemosa was found in acidic to slightly alkaline pH but with low salinity (1.35 % − 1.92 %) soils. Sonneratia caseolaris was recorded in soils with the lowest salinity (0.83 % − 1.04 %). The findings offer valuable insights for decision-making processes for conserving and restoring mangrove forests, providing effective and sustainable environmental management strategies.

Microorganisms have historically coexisted with humans, animals, and the environment in a natural way. Like any other living being, microorganisms are subjected to environmental pressures that can eventually extinguish or strengthen their existence. In recent years, the emergence of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG) has raised an alert about their influence on human and animal health. In addition to ARBs found in nosocomial environments, recent studies point to the environment as an auxiliary hotspot for the spread of antimicrobial resistance. In this sense, this review covers research that investigated ARB and ARG in E. coli and Salmonella, occurrence and potential environmental reservoirs for the spread of antimicrobial resistance, as well as a discussion on how bacterial resistance affects public health, the detection and treatment methods currently employed to reduce or remove this pollutant from water treatment plants (WTP) and sewage treatment plants (WWTP). The results indicated that the great increase in bacterial resistance may be linked, among other reasons, to repetitive contact with residual concentrations of antibiotics present in the environment, causing the bacteria to suffer from selective pressure and if resistant to one or more antibiotics. Thus, public health is compromised, since commonly used antibiotics are often ineffective in treating disease-resistant pathogenic bacteria. From this perspective, studies have shown the importance of consistent detection methods, which allow the tracking and analysis of sources of antimicrobial resistance on a global scale, in addition to the need to improve advanced treatment to reduce the ARG and ARB of WTPs and WWTPs. The first two sections of this review article present an overview of the problems related to the occurrence and dissemination of antimicrobial resistance (AMR) in bacteria, with a focus on E. coli and Salmonella, identified by the WHO as bacteria of global priority for surveillance. The third section addresses environmental and public health issues related to AMR. Section 4 addresses analytical methods for detecting antibiotic-resistant bacteria (E. coli and Salmonella) in the most diverse types of samples. In the subsequent chapter, the application of technologies for the removal/reduction of ARB and ARG as environmental contaminants in water and wastewater is discussed. Finally, future perspectives and gaps to be faced by this field of research are presented. A critical analysis of the authors is presented in each section.