Contamination Of Water Systems Research Articles

D-limonene-based polymeric adsorbent for effective Pb(II) ion removal: A comprehensive study on sorption behaviour and environmental applicability

In response to the pressing global health concern posed by lead contamination in water systems, we introduce a novel green synthesis polymer, LIM-co-DVB-co-VIM, derived from D-Limonene, a natural terpene. This polymer offers high surface area and tenability making it a promising solution for Pb(II) ion removal. Our study involves a thorough characterization of the adsorbent and optimization of operational parameters for selective Pb(II) ion removal. Adsorption follows Langmuir isotherm and pseudo-second-order kinetics, with an adsorption capacity of 31.8 mg g⁻¹ and rapid removal efficiency. Thermodynamic analysis reveals the exothermic and spontaneous nature of the adsorption process. Selectivity studies confirm the polymer's ability to selectively adsorb Pb(II) ions. Desorption experiments with 0.1 M HCl achieve a quantitative recovery of 95.7%, demonstrating efficient regeneration. Application to real water samples validates the method's effectiveness, highlighting the importance of environmentally friendly solutions in addressing water contamination challenges.

Ru@Co3O4@g-C3N4 as a novel adsorbent for enhanced copper and cadmium abolition

Elimination of heavy metals from contaminated water systems is of prime distress due to their capacity to prompt toxic impact on the flora and fauna. The usage of innovative nano-engineered materials predominantly opens up smart prospects for the treatment of persistent heavy metal adulterated water resources. This study presents an ultrasonic-assisted sol-gel production of Ru@Co3O4@g-C3N4 nanostructure that was utilized to remove Cu+2 and Cd+2 ions from aqueous solutions. The X-ray diffraction investigation revealed the development of RuO2, Co2O3 and g-C3N4 phases, and the relevant elemental composition was verified by the photoelectron spectroscopy and EDX. The dispersion of the metal oxides within the nitride sheets was evidenced by scanning and transmission electron microscopy. The initial metal ions concentration, pH, and contact time effects were investigated through batch experiments. The adsorption isotherm models matched the Langmuir isotherm well, whereas the kinetics model data perfectly fitted the pseudo-second-order model. The maximum adsorption capacities of Cu+2 and Cd+2 ions on the nanocomposite Ru@Co3O4@g-C3N4 were 696.9 and 564.5 mg/g, respectively. A mechanism based on a viable covalent type of bonding developed by the delocalized -conjugated electrons of the triazine ring and functional groups were efficiently involved in the metal ions anchoring and ultimate elimination. Thus, the suitability of the Ru@Co3O4@g-C3N4 nanocomposite for eradicating heavy metals, including Cu+2 and Cd+2, was established.

Sustainable approaches for removing toxic heavy metal from contaminated water: A comprehensive review of bioremediation and biosorption techniques

In this comprehensive study, highlights emerging environmentally friendly methods to eliminating hazardous heavy metals from contaminated water, with an emphasis on bioremediation and biosorption. Breakthroughs, such as the combination of biological remediation and nanotechnology to improve the elimination of metals effectiveness and the use of genetically modified microbes for targeted pollutant breakdown. Developing biosorption materials made from agricultural waste and biochar, this indicates interesting areas for future research and emphasizes the necessity of sustainable practices in tackling heavy metal contamination in water systems. There seems to be a surge in enthusiasm for the utilization of biological remediation and biosorption methods as sustainable and viable options for eliminating heavy metals from contaminated water in the past couple of decades. The present review intends to offer an in-depth review of the latest understanding and advances in the discipline of biological remediation methods like bioaccumulation, biofiltration, bio-slurping, and bio-venting. Biosorption is specifically explained and includes waste biomass as biosorbent with the removal mechanisms and the hindrances caused in the process are detailed. Advances in biosorption like microbes as biosorbents and the mechanism involved in it. Additionally, novel enhancement techniques like immobilization, genetic modification, and ultrasound-assisted treatment in microbial sorbent are clarified. However, the review extended with analyzing the future advances in the overall biological methods and consequences of heavy metal pollution.

Emerging nitrogen-fixing cyanobacteria for sustainable cotton cultivation

Amid growing environmental concerns and the imperative for sustainable agricultural practices, this study examines the potential of nitrogen-fixing cyanobacteria as biofertilizers, particularly in cotton cultivation. The reliance on synthetic nitrogen fertilizers (SNFs), prevalent in modern agriculture, poses significant environmental challenges, including greenhouse gas emissions and water system contamination. This research aims to shift this paradigm by exploring the capacity of cyanobacteria as a natural and sustainable alternative. Utilizing advanced metabarcoding methods to analyze the 16S rRNA gene, we conducted a comprehensive assessment of soil bacterial communities within cotton fields. This study focused on evaluating the diversity, structure, taxonomic composition, and potential functional characteristics of these communities. Emphasis was placed on the isolation of native N2-fixing cyanobacteria strains rom cotton soils, and their subsequent effects on cotton growth. Results from our study demonstrate significant plant growth-promoting (PGP) activities, measured as N2 fixation, production of Phytohormones, Fe solubilization and biofertilization potential of five isolated cyanobacterial strains, underscoring their efficacy in cotton. These findings suggest a viable pathway for replacing chemical-synthetic nitrogen fertilizers with natural, organic alternatives. The reintegration of these beneficial species into agricultural ecosystems can enhance crop growth while fostering a balanced microbial environment, thus contributing to the broader goals of global sustainable agriculture.

Synthesis and characterization of nanocomposite based polymeric membrane (PES/PVP/GO-TiO2) and performance evaluation for the removal of various antibiotics (amoxicillin, azithromycin & ciprofloxacin) from aqueous solution

The escalating global concern regarding antibiotic pollution necessitates the development of advanced water treatment strategies. This study presents an innovative approach through the fabrication and evaluation of a Polyethersulfone (PES) membrane adorned with GO-TiO2 nanocomposites. The objective is to enhance the removal efficiency of various antibiotics, addressing the challenge of emerging organic compounds (EOCs) in water systems. The nanocomposite membranes, synthesized via the phase inversion method, incorporate hydrophilic agents, specifically GO-TiO2 nanocomposites and Polyvinylpyrrolidone (PVP). The resultant membranes underwent comprehensive characterization employing AFM, EDS, tensile strength testing, water contact angle measurements, and FESEM to elucidate their properties. Analysis revealed a substantial improvement in the hydrophilicity of the modified membranes attributed to the presence of hydroxyl groups within the GO-TiO2 structure. AFM images demonstrated an augmentation in surface roughness with increasing nanocomposite content. FESEM images unveiled structural modifications, leading to enhanced porosity and augmented water flux. The pure water flux elevated from 0.980 L/m2.h−1 for unmodified membranes to approximately 6.85 L/m2.h−1 for membranes modified with 2 wt% nanocomposites. Membrane performance analysis indicated a direct correlation between nanocomposite content and antibiotic removal efficiency, ranging from 66.52% to 89.81% with 4 wt% nanocomposite content. Furthermore, the nanocomposite-modified membrane exhibited heightened resistance to fouling. The efficacy of the membrane extended to displaying potent antibacterial properties against microbial strains, including S. aureus, E. coli, and Candida. This study underscores the immense potential of GO-TiO2 decorated PES membranes as a sustainable and efficient solution for mitigating antibiotic contamination in water systems. The utilization of nanocomposite membranes emerges as a promising technique to combat the presence of EOC pollutants, particularly antibiotics, in water bodies, thus addressing a critical environmental concern.

Adsorption capacity of pollutants from water by graphene and graphene-based materials: a bibliographic review

The increase in the contamination of water systems by endocrine disruptive chemicals is of great concern once they pose risk to human and animal lives. The need for materials to adsorb these pollutants are of great concern. Graphene, a newly discovered material from the carbonaceous group, has been demonstrating interesting applications in contaminants removal from water. Therefore, this study aimed to review manuscripts regarding the adsorption capacity of herbicides and pesticides, bisphenol A, and carbamazepine from water using graphene or graphene-based materials as an adsorbent. Research of manuscripts was performed in Science Direct, Wiley Online Library, and Periódicos Capes database regarding the application of this nanomaterial in the removal of these pollutants from water. This review demonstrated that graphene itself or hybrid with other materials is very efficient in removing these contaminants, with high-efficiency rates. However, new studies can be performed to improve graphene applications and effectiveness.

A comprehensive study on the co-removal of Cr (VI) and ciprofloxacin via microbial-photocatalytic coupling: Mechanistic insights and performance evaluation

The increasing contamination of water systems by antibiotics and heavy metals has become a growing concern. The intimately coupled photocatalysis and biodegradation (ICPB) approach offers a promising strategy for the effective removal of mixed pollutants. Despite some prior research on ICPB applications, the mechanism by which ICPB eliminates mixed pollutants remains unclear. In our current study, the ICPB approach achieved approximately 1.53 times the degradation rate of ciprofloxacin (CIP) and roughly 1.82 times the reduction rate of Cr (VI) compared to photocatalysis. Remarkably, after 30 days, the ICPB achieved a 96.1% CIP removal rate, and a 97.8% reduction in Cr (VI). Our investigation utilized three-dimensional fluorescence analysis and photo-electrochemical characterization to unveil the synergistic effects of photocatalysis and biodegradation in removal of CIP and Cr (VI). Incorporation of B–Bi3O4Cl (B-BOC) photocatalyst facilitated electron-hole separation, leading to production of ·O2−, ·OH, and h+ species which interacted with CIP, while electrons reduced Cr (VI). Subsequently, the photocatalytic products were biodegraded by a protective biofilm. Furthermore, we observed that CIP, acting as an electron donor, promoted the reduction of Cr (VI). The microbial communities revealed that the number of bacteria favoring pollutant removal increased during ICPB operation, leading to a significant enhancement in performance.

Preferential separation of a radioactive TcO4- surrogate from a mixture of oxoanions by a cationic MOF.

Preferential trapping of a selected metal-oxoanion from a mixture of other metal-oxoanionic toxic pollutants in water has been demonstrated by implementing energy-efficient adsorption followed by the ion-exchange method, utilizing a hydrolytically stable cationic metal-organic framework (MOF). The cationic MOF exhibits ultrafast and selective extraction efficiency towards ReO4- (a surrogate anion of radioactive TcO4-) over other metal-oxoanions in contaminated water systems.

Molecular level investigation of interactions between pharmaceuticals and β-cyclodextrin (β-CD) functionalized adsorption sites for removal of pharmaceutical contaminants from water

This study describes a novel application of the use of molecular modeling tools for investigating the adsorption of organic micropollutants (OMPs) from water by nanocomposites. The partitioning of pharmaceuticals onto β-Cyclodextrin (β-CD) functionalized adsorbents was investigated at the molecular level to explore the atomistic interactions of pharmaceutical contaminants in water systems with β-CD and to provide insight into possible approaches for removal of pharmaceuticals from water. Molecular electrostatic surface potential mapping of β-CD derivatives was employed to examine the impact of substitution degree of β-CD and type of grafting agent on host-guest complexation. The stability of the complexes of selected pharmaceuticals and β-CD derivatives were assessed via molecular dynamics simulations to evaluate competitive adsorption between organic micropollutants (OMPs) and between OMPs and fulvic acid, a representative natural organic material (NOM) component found in water systems. Molecular electrostatic surface potential maps showed that grafting agents with aromatic and amine functional groups were found to provide attractive interactions for negatively charged OMPs. In addition, optimization of substitution degree of β-CD is necessary to enhance adsorption of target OMPs. Furthermore, it was found that aromatic ring bearing grafting agents can provide additional electrostatic attractions by π-π interactions with the aromatic ring of the OMPs. The impact of common water quality characteristics on adsorption was assessed and it was revealed that the effect of pH and calcium on adsorption depends on the ionizable functional groups present on the grafting agent. Molecular dynamics simulations showed that adsorption of target OMPs does not solely depend on hydrophobicity but is affected by electrostatic interactions. The simulations revealed that fulvic acid which is commonly present in environmental waters can be a competitor with ibuprofen for the β-CD cavity. Ultimately, this study showed that molecular level simulation can be effectively employed to investigate adsorption of OMPs by β-CD functionalized adsorbents and could be employed to enhance their design and subsequent environmental applications.

Recent Advances in Metal-Organic Framework (MOF)-Based Photocatalysts: Design Strategies and Applications in Heavy Metal Control.

The heavy metal contamination of water systems has become a major environmental concern worldwide. Photocatalysis using metal-organic frameworks (MOFs) has emerged as a promising approach for heavy metal remediation, owing to the ability of MOFs to fully degrade contaminants through redox reactions that are driven by photogenerated charge carriers. This review provides a comprehensive analysis of recent developments in MOF-based photocatalysts for removing and decontaminating heavy metals from water. The tunable nature of MOFs allows the rational design of composition and features to enhance light harvesting, charge separation, pollutant absorptivity, and photocatalytic activities. Key strategies employed include metal coordination tuning, organic ligand functionalization, heteroatom doping, plasmonic nanoparticle incorporation, defect engineering, and morphology control. The mechanisms involved in the interactions between MOF photocatalysts and heavy metal contaminants are discussed, including light absorption, charge carrier separation, metal ion adsorption, and photocatalytic redox reactions. The review highlights diverse applications of MOF photocatalysts in treating heavy metals such as lead, mercury, chromium, cadmium, silver, arsenic, nickel, etc. in water remediation. Kinetic modeling provides vital insights into the complex interplay between coupled processes such as adsorption and photocatalytic degradation that influence treatment efficiency. Life cycle assessment (LCA) is also crucial for evaluating the sustainability of MOF-based technologies. By elucidating the latest advances, current challenges, and future opportunities, this review provides insights into the potential of MOF-based photocatalysts as a sustainable technology for addressing the critical issue of heavy metal pollution in water systems. Ongoing efforts are needed to address the issues of stability, recyclability, scalable synthesis, and practical reactor engineering.

Legionellosis in Poland in 2018-2021.

The aim of this study is to compare the epidemiological situation of legionellosis in Poland in 2018-2021 to prior years, taking into account the impact of the COVID-19 pandemic in 2020-2021. The assessment is based on national surveillance data published in the annual bulletin "Infectious Diseases and Poisons in Poland" from 2013 to 2021, as well as data from Legionnaires' disease case reports collected and sent to the Department of Epidemiology of Infectious Diseases and Surveillance NIPH NIH - NRI by sanitary and epidemiological stations or submitted to EpiBase. In Poland, both Legionnaires' disease (an acute infection that progresses to pneumonia) and Pontiac fever (a mild, flu-like sickness) are reported. In 2018-2021, a total of 255 cases of legionellosis were registered, including 236 cases of Legionnaires' disease and 19 cases of Pontiac fever. Each year, there was an increase in the number of notifications compared to the annual median number of cases from 2013-2017. The annual incidence rate in 2019 (0.23 per 100,000 population) was the highest since the start of legionellosis case registration in Poland. It declined again during the years of the COVID-19 pandemic. The notifications occurred throughout the country, but the highest notification rate was observed in the western belt of voivodeships. Pomorskie reported the highest incidence, accounting for more than 20% of all registered cases. The median incidence of Legionnaires' disease in men (0.23 per 100,000) was more than twice that of women (0.10), with the highest incidence (0.58) recorded in men 65 years of age or older. All indigenous cases of Legionnaires' disease were sporadic; all but three patients were hospitalized. State Sanitary Inspection reported 26 fatal cases of Legionnaires' disease (mortality = 11%). Twenty-four cases were linked to contaminated water systems in health-care settings, and 21 cases were likely associated with travel abroad. Although the number of notifications has increased in recent years, Legionnaires' disease is still an infrequently diagnosed respiratory infection in Poland, and the reported incidence remains one of the lowest in the entire EU. The most affected demographic group is men aged 65 and older. Improving the early diagnosis of Legionnaires' disease in healthcare settings remains a priority.

Sources of antimony contamination and its migration into water systems of Xikuangshan, China: Evidence from hydrogeochemical and stable isotope (H, O, S, and Sr) signatures

The Xikuangshan (XKS) mine was selected for a comprehensive Sb-related hydrogeochemical study because of its significant Sb contamination in water systems. Hydrochemical data, specifically multi-isotope (H, O, S, and Sr) data, were conducted to elucidate the primary sources and migration processes of Sb responsible for water system contamination. At the XKS Sb mine, water is near-neutral to alkaline and is characterized by high concentrations of SO42− and Sb. Sb occurs as Sb(OH)6− (the dominant species) in these oxidized waters. The hydrochemistry is mainly controlled by carbonate dissolution and silicate weathering. δ2HH2O and δ18OH2O values indicate that the infiltration recharge of mine water and mining activities regulate the migration of Sb in groundwater. δ34SSO4 and δ18OSO4 values indicate that dissolved SO42− and Sb primarily come from stibnite oxidation, bacterial SO42− reduction has either not occurred or is extremely weak, and the reductive dissolution of Fe (III) hydroxides does not significantly affect Sb migration in water. The 87Sr/86Sr ratios further indicate that the discharge of solid mine wastes leaching and smelting water is a crucial source of Sb contamination in groundwater. In addition, the relationship between δ34SSO4 and δ87Sr values suggests the complexity of the contamination source and migration of Sb in water. Finally, a robust conceptual hydrogeochemical model was developed using isotopic tools in combination with detailed hydrogeological and hydrochemistry characterization to describe the contamination source and migration of Sb in water systems at the XKS Sb mine.

Biofilms Controlling in Industrial Cooling Water Systems: A Mini-Review of Strategies and Best Practices.

Biofilm formation and growth is a significant concern for water treatment professionals, as it can lead to the contamination of water systems and pose a threat to public health. Biofilms are complex communities of microorganisms that adhere to surfaces and are embedded in an extracellular matrix of polysaccharides and proteins. They are notoriously difficult to control, as they provide a protective environment for bacteria, viruses, and other harmful organisms to grow and proliferate. This review article highlights some of the factors that favor biofilm growth, as well as various strategies for controlling biofilm in water systems. Adopting the best available technologies, such as wellhead protection programs, proper industrial cooling water system maintenance, and filtration and disinfection, can prevent the formation and growth of biofilms in water systems. A comprehensive and multifaceted approach to biofilm control can reduce the occurrence of biofilms and ensure the delivery of high-quality water to the industrial process.

Prevalence and Characterization of Legionella pneumophila and Related Species from Water-Based Recreational Sites

Abstract Background and Objectives Legionella is a genus of gram-negative bacteria common in soil and aquatic systems and is associated with protists. They have emerged as a pathogenic group due to the increased use and poor maintenance of artificial water environments. This study aims at phenotypic and molecular identification of Legionella in water and swab samples collected from water-based recreational sites. The biofilm-forming ability of Legionella on exposure to various temperatures and iron concentrations was also studied. Methods A total of 60 samples including 30 swab samples and 30 water samples (decorative fountain ponds, swimming pools, garden sprinklers, drip irrigation system) were collected from in and around Mangalore, Karnataka, India. From each source, swab and water samples were collected as per the Indian standard IS: 1622. The collected samples were processed within 4 hours of collection. The samples were subjected to microbiological and chemical estimation followed by filtration through a 0.2 µm membrane filter. Isolation of Legionella from collected samples was performed as per US Centers for Disease Control and Prevention guidelines 2005. The positive isolates were then checked for biofilm-forming ability at various temperatures (25°C, 35°C, and 45°C) and iron concentration (3 mg/L, 30 mg/L, and 300 mg/L) using crystal violet assay. Results Out of 30, water and swab samples tested, one water sample from a garden sprinkler, swimming pool, and one from both water and swab samples from a decorative fountain showed the presence of Legionella. A biofilm study of Legionella at various temperatures and iron concentrations categorized the bacteria as a moderate biofilm former. Conclusion This study revealed that most of the water and swab samples were found to be negative for Legionella that is quite encouraging and the contamination of water systems in recreational facilities can be reduced by decontamination techniques and proper hygienic practices.

Identification, prevention, and treatment of Legionella in bath facility water systems in South Korea

Legionella bacteria infect people via aerosol transmission. These pathogens can meaningfully affect people with weak immune systems and the older adult population. Legionella proliferate in water systems at temperatures between 25 and 45 °C, the optimum range for bath facilities. Here, we discuss how and where water systems can be contaminated by Legionella in bath facility water systems in South Korea. An epidemiological investigation of Legionella detection data from the Korea Disease Control and Prevention Agency was conducted to understand the tendencies of general outbreaks of water system types in building groups. Onsite investigations were then conducted to identify the causes of contamination in water systems in actual Legionella detection cases. According to annual Legionella detection data, the highest rate of Legionella was detected in hot bathtub water. Onsite investigations revealed that sand filter circulation systems for bathtubs are susceptible to Legionella growth. Overall, this study examined the mechanisms of buidling water systems from a building engineering perspective in order to provide valuable information for future studies and strategies to control Legionella growth in bath facility water systems.

A novel and sustainable pipette-tip solid-phase microextraction testing of six carbon-based nanomaterials as proof of concept for the determination of sixteen emerging pollutants from active veterinary principles

A new and optimized solid-phase microextraction method using pipette tips is proposed as a proof of concept for the extraction of sixteen veterinary drugs: antimicrobials (trimethoprim, enrofloxacin and sulfamethoxazole), external antiparasitics (thiamethoxam, clothianidin, imidacloprid, fipronil, clorpyrifos, lufenuron, and permethrin), internal antiparasitics (fenbendazole and albendazole), anti-inflammatories (prednisolone, diclofenac, and betamethasone), and an anticoccidial (robenidine). In this context, the device has been challenged by many analytes with very different structural and physicochemical properties, which presents a major difficulty in the simultaneous extraction of different APs. To this end, six carbon-based nanomaterials (multi-walled carbon nanotubes (MWCNTs), graphite, graphene oxide (GO), electrochemically expanded graphene (GEQE), electrochemically reduced graphene (ERGO), and commercial and synthetic graphene oxide) were evaluated packing sorbent in the extraction column. Several NMs (GEQE and ERGO) were used for the first time as sorbents in microextractions and were fabricated, synthesized, and characterized in the laboratory. Simple materials available in any laboratory were used to fabricate the devices, showing the simplicity, ease of preparation, and low cost of the proposed device. Optimization of the microextraction device (pipette tip) was performed using chemometric tools (design of experiments and reaction surface methodology) to obtain the sorbent mass and pH to improve retention rates. In addition, a comparative analysis of the extraction of single and multi-analytes and of a batch and a continuous system was performed. Real samples were examined to evaluate the proper performance of the instrument, which can be used in a preanalytical phase of sample handling to isolate analytes from complex samples. Furthermore, a very detailed and comparative study of the physicochemical properties of NM compared to the analytes was performed, providing valuable information on the interactions taking place and the experimental conditions required, which can be extrapolated to many analyses with similar properties. Additionally, the AGREE software was used to determine the environmental friendliness of the extraction methods and to compare them with the literature. Based on the latter considerations, this multi-analyte microextraction method holds great promise for future applications in the determination of novel environmental contaminants in water systems.

Electrochemical CNT filter functionalized with metal-organic framework for one-step antimonite decontamination

Currently, there is a lack of advanced nanotechnology designed to efficiently remove antimony (Sb) from contaminated water systems. Sb most commonly appears as antimonite (Sb(III)) or as the anion antimonate (Sb(V)). Sb(III) is approximately ten times more toxic than Sb(V), and Sb(III) is also harder to eliminate because of its motility and charge neutrality. The work presented here developed an electrochemical filtration technology for the direct elimination of Sb(III) from contaminated water. The primary components of the filtration system were an electroactive carbon nanotube (CNT) membrane that were functionalized with the Sb-specific UiO-66(Zr), an metal-organic framework. In an electric field, the UiO-66(Zr)/CNT nanohybrid filter enabled in situ transformation of Sb(III) to less harmful Sb(V). The Sb(V) was then effectively adsorbed by the UiO-66(Zr). The removal efficiency (90.5%) and rate constant (k1 = 0.0272 min−1) toward Sb(III) removal was 1.3 and 1.4 times greater than that of CNT filter. The abundance of available adsorption sites of the nanohybrid filter, flow-through construction, and electrochemical activity combined to rapidly remove Sb(III) from water. The underlying functioning of the nanohybrid filter was determined with a series of process experiments and structural characterizations. The filter was effective over a broad range of pH values and in a variety of complex aqueous environments. Once loaded with Sb, the UiO-66(Zr)/CNT filter could be washed with a dilute NaOH solution to efficiently refresh its activity. The results of this work offer a direct, efficient strategy that integrates nanotechnology, electrochemistry, and membrane separation to remove antimony and potentially other heavy metals from contaminated water.

Synthesis of Xanthan Gum Anchored α-Fe2O3 Bionanocomposite Material for Remediation of Pb (II) Contaminated Aquatic System.

Increases in community and industrial activities have led to disturbances of the environmental balance and the contamination of water systems through the introduction of organic and inorganic pollutants. Among the various inorganic pollutants, Pb (II) is one of the heavy metals possessing non-biodegradable and the most toxic characteristics towards human health and the environment. The present study is focussed on the synthesis of efficient and eco-friendly adsorbent material that can remove Pb (II) from wastewater. A green functional nanocomposite material based on the immobilization of α-Fe2O3 nanoparticles with xanthan gum (XG) biopolymer has been synthesized in this study to be applied as an adsorbent (XGFO) for sequestration of Pb (II). Spectroscopic techniques such as scanning electron microscopy with energy dispersive X-ray (SEM-EDX), Fourier transform infrared (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet visible (UV-Vis) and X-ray photoelectron spectroscopy (XPS) were adopted for characterizing the solid powder material. The synthesized material was found to be rich in key functional groups such as -COOH and -OH playing important roles in binding the adsorbate particles through ligand-to-metal charge transfer (LMCT). Based on the preliminary results, adsorption experiments were conducted, and the data obtained were applied to four different adsorption isotherm models, viz the Langmuir, Temkin, Freundlich and D-R models. Based on the high values of R2 and low values of χ2, the Langmuir isotherm model was found to be the best model for simulation of data for Pb (II) adsorption by XGFO. The value of maximum monolayer adsorption capacity (Qm) was found to be 117.45 mg g-1 at 303 K, 126.23 mg g-1 at 313 K, 145.12 mg g-1 at 323 K and 191.27 mg g-1 at 323 K. The kinetics of the adsorption process of Pb (II) by XGFO was best defined by the pseudo-second-order model. The thermodynamic aspect of the reaction suggested that the reaction is endothermic and spontaneous. The outcomes proved that XGFO can be utilized as an efficient adsorbent material for the treatment of contaminated wastewater.

ОЦІНКА МОЖЛИВОСТІ РЕГУЛЮВАННЯ ВОДНОГО РЕЖИМУ ОКРЕМИХ ТЕРИТОРІЙ ЧОРНОБИЛЬСЬКОЇ ЗОНИ ВІДЧУЖЕННЯ

The characteristics of the natural features of the Chernobyl Exclusion Zone (CEZ), in particular the nature of the relief, soil cover, main plant groups, and landscape characteristics, are provided. The hydrographic network of the region is detailed, represented by rivers, lakes, ponds, dams of the Pripyat and Uzh rivers, the reservoir of the Kyiv HPP, reclamation channels, water mirrors in front of filtration dams. It was noted that the main processes that form the current level of radioactive contamination of water systems in the CEZ are natural processes of radioactive decay, vertical sinking and geochemical fixation of radionuclides. Analysis of water pollution monitoring data in rivers and canals of the exclusion zone shows that by regulating water levels in most areas of the catchment areas of the CEZ, it is impossible to significantly influence the reduction of water pollution in them compared to the effects of their natural self-purification. Therefore, it is impractical to continue large-scale works on water flow regulation by hydrotechnical structures in order to minimize the removal of radioactive substances beyond the exclusion zone. It is advisable to leave in operation only those systems that allow maintaining increased moisture in peatlands, reducing the risks of fires. The studies carried out on the reclamation system “Buryakivka” in the basin of the Sakhan River, as an experimental training ground for the regulation of the regime of floodplains of the CEZ, are covered in detail. The use of the method of remote sensing of the Earth (DSS) to control the water regime and monitor the transformation of reclamation systems into wetlands is substantiated. In particular, spectral analysis of image pixels in different parts of the spectrum using vegetation indices. A positive nature protection effect from the increase in the area of wetlands in the Exclusion Zone was noted in the context of the prospects of climate change and in the context of the probability of increasing cases of dry periods in the territory of Polissia.

Acute Neurotoxicity and Hyperlactatemia Due to Hemodialysis Water System Contamination: A New Relationship

Acute Neurotoxicity and Hyperlactatemia Due to Hemodialysis Water System Contamination: A New Relationship