Contamination Of Water Bodies Research Articles

Bifunctional Zirconium Phosphate with Greigite for Electrochemical Detection and Simultaneous Removal of Heavy Metal Ions and Nitro Compounds.

Electrochemical sensing is emerging as a method of choice for the sensing and monitoring of contaminants in water. Various sensing platforms have been designed for sensing heavy metal ions and organic pollutants in water bodies. Herein, we report a new electrochemical platform that can be used for the detection of both heavy metal ions and nitro-based organic contaminants in water bodies. The electrochemical sensor uses a modified electrode based on Fe3S4-impregnated zirconium phosphate (ZrP) nanoparticles synthesized by a simple ultrasonication method. The ZrP@Fe3S4 nanoparticles were thoroughly characterized by power X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), and ζ-potential studies. The material exhibits an excellent electrochemical performance for the detection of Pb2+, Hg2+, nitrophenol, nitroaniline, and picric acid with low limits of detection of ca. 0.93, 0.70, 0.98, 1.10, and 1.53 ppm, respectively. Since ZrP@Fe3S4 nanoparticles are magnetically recyclable, their adsorption capacity and recyclability have been thoroughly investigated for the uptake of Pb2+ and Hg2+ ions from contaminated water. We observed that the adsorption of Pb2+ and Hg2+ ions on ZrP@Fe3S4 is best described by the Langmuir isotherm and pseudo-second-order kinetic models, with adsorption capacities of 219.44 and 118.4 mg/g, respectively. Similarly, the removal efficiency of ZrP@Fe3S4 was found to be 91, 57.6, and 31.3% for nitrophenol, nitroaniline, and picric acid, respectively. Furthermore, the theoretical calculations using density functional theory (DFT) were carried out to find the adsorption energy, affinity, and point of adsorption, which are in line with the experimental results. DFT calculations further suggest that the incorporation of Fe3S4 on ZrP improves the surface charge density and promotes efficient electron transfer between the electrode and the analyte. We have shown the real-time analysis of Dal lake water as a proof of concept, and the synthesized composite exhibits good recovery and promising results for metal ion sensing. ZrP@Fe3S4 demonstrated an excellent cycling stability and long-term stability without noticeable degradation for 1 week.

Application of molecularly imprinted polymers in the water environmental field: A review on the detection and efficient removal of emerging contaminants

The emerging contaminants in the environment pose a threat to ecological security and human health. At present, traditional technologies are difficult to detect and remove existing trace emerging contaminants in water bodies. Therefore, efficient removal of low concentration emerging contaminants is a key issue in ensuring water safety. As an emerging technology, molecular imprinting technology (MIT) can synthesize polymers with specific recognition ability for target pollutants, providing a new approach for efficient removal of emerging contaminants. It is worth noting that combining MIT with traditional catalysts is an effective method to improve detection limits and removal efficiency. This review mainly introduced the research progress of using MIT to detect pollutants in various sensors and using advanced oxidation technology to remove pollutants in recent years, focusing on the preparation and application of MIT-based photocatalysts, electrocatalysts, and Fenton-like catalysts. In addition, possible interactions between the target analyte and MIT were discussed, as well as the reusability and stability of imprinted catalysts in water treatment, and their potential ecological toxicity risks were analyzed. Finally, the challenges of MIT based pollutant mitigation and the application prospects of molecular imprinting technology in environmental analysis were elaborated from multiple perspectives.

SegNet‐VOLO model for classifying microplastic contaminants in water bodies

AbstractIn recent times, microplastics (MPs) have emerged as notable contaminants within several environments, especially in water bodies. The characterization and description of MPs necessitate extensive and laborious analytical methods, making this part of MPs research an essential issue. In this research, SegNet‐Vision Outlooker (VOLO), a computer vision and deep learning (DL)‐based model, is proposed for detecting and classifying MPs present in a water environment. This research model includes step‐by‐step processes such as data collection, preprocessing, filtering and enhancement, augmentation, segmentation, feature extraction, and classification for detecting MPs. The key objective of this research model is to improve the classification accuracy in detecting MPs and to validate the model's effectiveness in handling holographic images. The Holographic Image MPs dataset is collected and used to evaluate the model. In preprocessing, image rescaling is performed to match the proposed model's input resolution as 224 × 224. After rescaling, the images are applied to remove noise using a bilateral filtering technique. The contrast‐limited adaptive histogram equalization (CLAHE) method is applied to enhance the image with better contrast and brightness, which helps the model to segment and classify the images accurately. The enhanced images are applied to the SegNet model for segmentation, which segmented the images according to the MP classes. Based on the segmented images, the VOLO‐D1 model extracted the features and classified the images to detect the MPs present in the images. The SegNet‐VOLO model attained 97.70% detection rate, 98.26% accuracy, 98.13% F1‐score, and 98.62% precision. These performances are compared with the various existing models discussed in the review, where the research model outperformed all the models with better performances.

Protein level alteration and micronuclei induction in Channa punctatus fish exposed to chlorpyrifos and their alleviation by Melissa officinalis and Mentha piperita extracts

Aim: To assess alteration in the protein levels of major organs and induction of micronuclei in the freshwater fish, Channa punctatus following exposure to chlorpyrifos, while also investigating the potential mitigating effects of extracts from Melissa officinalis and Mentha piperita on the adverse impacts induced by this pesticide. Methodology: Two weeks of acclimatized healthy fish were divided into four different groups. Group G1 served as the control group, while G2 contained chlorpyrifos (LC50/10, 96 hr). Group G3 was exposed to chlorpyrifos (LC50/10, 96 hr) along with 8 mg l-1 of Melissa officinalis ethanolic extract, and similarly, G4 contained chlorpyrifos (LC50/10, 96 hr) along with 8 mg l-1 ethanolic extract of Mentha piperita. Sampling was conducted over various durations of 7, 14, 21, and 28 days. The ethanolic extracts of Melissa officinalis and Mentha piperita were used as remedial compounds as they are rich in several bioactive compounds, primarily polyphenols. Results: The investigation revealed a notable decrease in the total protein content of kidney, liver, gills and muscles following exposure to chlorpyrifos after each sampling duration. While, upon exposure to remedies containing the ethanolic extracts of Melissa officinalis and Mentha piperita, the protein levels exhibited a significant recovery (p < 0.05) in a duration-dependent manner, compared to the control group. This suggests a promising ameliorative capability of Melissa officinalis and Mentha piperita against chlorpyrifos toxicity. Further, the induction of micronuclei by chlorpyrifos and their subsequent recovery through the application of phytoextracts Melissa officinalis and Mentha piperita displayed a similar pattern, indicating the potential protective effects of these extracts against chlorpyrifos-induced genotoxicity. Interpretation: It is plausible to conclude that standardized doses of Melissa officinalis and Mentha piperita hold the potential to enhance aquaculture practices and safeguard fish production in agriculturally contaminated water bodies. These findings emphasize their valuable contribution in sustaining fish health amidst toxic environments. Key words: Channa punctatus, Chlorpyrifos, Melissa officinalis, Mentha piperita

Biocomposite Based on Polyhydroxybutyrate and Cellulose Acetate for the Adsorption of Methylene Blue

Industrialization and globalization have caused severe environmental problems, such as contaminating water bodies by toxic agents from various industries, generating a significant loss of biodiversity and health risks. Globally, approximately 80% of wastewater is discharged without treatment, worsening the situation. However, in Colombia, initiatives have been taken to improve wastewater management, with ambitious investments and targets to improve treatment infrastructure. Recently, advanced technologies have been developed to treat wastewater, including more efficient and sustainable biological methods, such as using coconut-derived adsorbent biomaterials, rich in useful properties for the adsorption of pollutants in solutions. This research focuses on developing a composite biomaterial using cellulose acetate (CA) extracted from coconut mesocarp and polyhydroxy butyrate (PHB), by the casting method, to treat wastewater. Adsorption tests with the tracer methylene blue (MB) were carried out in the Energy and Environment laboratory of the University of Cartagena. For this, MB solutions were prepared with 5 to 50 ppm concentrations. The analyses showed that the composite biomaterial is thermally stable and has good homogeneity and porosity. At a concentration of 40 ppm and a dosage of 10 mg of adsorbent, the adsorption efficiency was 89%, with an adsorption capacity of 35.98 mg/g. The above indicates that the composite biomaterial is presented as a sustainable, improved, and efficient solution to remove contaminants from wastewater, benefiting the environment and human health.

Efficient decaffeination with recyclable magnetic microporous carbon from renewable sources: Kinetics and isotherm analysis

Rapid global urbanization and population growth have ignited an alarming surge in emerging contaminants in water bodies, posing health risks, even at trace concentrations. To address this challenge, novel water treatment and reuse technologies are required as current treatment systems are associated with high costs and energy requirements. These drawbacks provide additional incentives for the application of cost-effective and sustainable biomass-derived activated carbon, which possesses high surface area and low toxicity. Herein, we synthesized microporous activated carbon (MAC) and its magnetic derivative (m-MAC) from tannic acid to decaffeinate contaminated aqueous solutions. Detailed characterization using SEM, BET, and PXRD revealed a very high surface area (>1800 m2/g) and a highly porous, amorphous, heterogeneous sponge-like structure. Physicochemical and thermal analyses using XPS, TGA, and EDS confirmed thermal stability, unique surface moieties, and homogeneous elemental distribution. High absorption performance (>96 %) and adsorption capacity (287 and 394 mg/g) were recorded for m-MAC and MAC, respectively. Mechanistic studies showed that the sorption of caffeine is in tandem with multilayer and chemisorptive mechanisms, considering the models’ correlation and error coefficients. π-π stacking and hydrogen bonding were among the interactions that could facilitate MAC-Caffeine and m-MAC-Caffeine bonding interactions. Regeneration and reusability experiments revealed adsorption efficiency ranging from 90.5 to 98.4 % for MAC and 88.6–93.7 % for m-MAC for five cycles. Our findings suggest that MAC and its magnetic derivative are effective for caffeine removal, and potentially other organic contaminants with the possibility of developing commercially viable and cost-effective water polishing tools.

Improving pH buffering capacity of an acid soil to regulate nutrient retention and mitigate water pollution using Calciprill and sodium silicate

In the tropics, high rainfalls and hot temperatures cause the formation of highly weathered acid soils with low pH buffering capacity (pHBC). Such soils are prone to nutrient losses via leaching, surface runoff, and volatilization. The poor nutrient retention of the highly weathered soils can cause environmental pollution in water bodies and detrimentally affect aquatic ecosystem. A preliminary study was conducted by mixing an acid soil (Bekenu series, Typic Paleudults) with Calciprill (80 %, 90 %, and 100 % Ca saturation) and sodium silicate (90, 105, 120, 135, and 150 kg ha−1) to determine the effects of the amendments on pH and pHBC of Bekenu series. Furthermore, a soil incubation study was carried out to determine the relationship between pH, pHBC, and effective cation exchange capacity (ECEC) after the soil was applied with Calciprill and sodium silicate and incubated for 40, 80, and 120 days. After the soil was harvested, the relationship between pHBC with soil exchangeable ammonium (NH4+), available nitrate (NO3-), and available phosphorus (P) to determine whether the combined use of Calciprill and sodium silicate is able to mitigate N and P losses through surface runoff and leaching to contaminate the surface and underground water bodies. The results from the studies showed that Calciprill and sodium silicate significantly increased soil pH and pHBC of Bekenu series. Notably, in the soil incubation study, the treatments with Calciprill and sodium silicate consistently improved pHBC compared with the soil without these amendments, suggesting that C2S4 (Calciprill at 90 % Ca saturation and sodium silicate at 135 kg ha−1) is the minimum amount of the amendments required to improve the pHBC of Bekenu series. The significant positive correlation between pH, pHBC, and ECEC throughout the soil incubation study indicates that the amendments are capable of improving pHBC of the Bekenu series when the pH and ECEC increase because of their alkalinity in addition to the presence of carbonate and silicate minerals. The significant positive correlations between pHBC with exchangeable NH4+ and available P at 40 and 80 DAI suggest that the Calciprill and sodium silicate can improve NH4+ and P availability for crop uptake. On the contrary, the significant negative correlation between pHBC and available NO3- at 80 DAI also suggests that the combined use of amendments can significantly reduce the NO3- contamination in water bodies because of improved pHBC. The most suitable combination for improving soil pH, ECEC, and pHBC is C2S4 (Calciprill at 90 % Ca saturation and sodium silicate at 135 kg ha−1) and it is possible to co-apply Calciprill and sodium silicate to mitigate NO3- contamination in water bodies. To further validate the findings of this study, greenhouse study is recommended to elucidate the plant-soil interactions.

Removal of lead ions onto potassium-type fine-grained zeolite prepared from dry or wet milling treatment

Potassium-type zeolite (KZ) was prepared from coal fly ash by hydrothermal activation treatment using potassium hydroxide solution and potassium-type fine-grained zeolite was prepared by dry milling (KZ-D) or wet milling (KZ-W). The effects of the different treatments on the Pb2+ adsorption performance were assessed. KZ-W resulted in a much smaller particle diameter (0.61 ± 0.12 µm) than KZ-D (1.4 ± 0.48 µm) and KZ (6.5 ± 0.49 µm). KZ-W also realized a higher pore volume, mean pore diameter, and specific surface area, than KZ-D and KZ. Additionally, KZ-W realized a greater Pb2+ adsorption capacity (242.6 mg/g) than KZ (195.3 mg/g) or KZ-D (188.9 mg/g). The adsorption phenomena were fitted to the Freundlich and Langmuir models to clarify the Pb2+ adsorption mechanism, and then both models showed a good fit to the experimental data (the correlation coefficients of 0.914–0.996 for Freundlich model and 0.897–0.981 for Langmuir model). Additionally, the ion exchange capability, elemental distribution, and binding energy before and after adsorption were analyzed. The results indicated that the physicochemical characteristics of the tested adsorbent surface affected the Pb2+ adsorption capacity in the aqueous phase. According to kinetics, the pseudo-second-order model matched the experimental data (the correlation coefficients of 0.996–0.999). The samples also demonstrated selective adsorption of Pb2+ in a binary solution. The results demonstrated that KZ-W can effectively remove Pb2+ from the aqueous phase and that it may be a useful tool for preventing contamination of water bodies.

Unraveling the pyridinic nitrogen vacancy in carbon nitride for photo-self Fenton-like purification of organic contaminants

This work reports a carbon nitride with pyridinic nitrogen-vacancy (N2CV-CN), which purifies organic contaminants via an in-situ photo-self Fenton-like reaction. Experiments and calculations demonstrated that the nitrogen-vacancy induces lone-paired (LP) and symmetry-unpaired electrons, promoting the formation of low-energy LP-π hybridized orbitals and helping to overcome the pairing energy required for oxygen to accept electrons. Furthermore, the nitrogen-vacancy accelerates film and intra-particle diffusion rates of organic contaminants on N2CV-CN, creating beneficial conditions for reactive oxide species to mineralize organic contaminants. Under sunlight and atmospheric oxygen, a photo-self Fenton-like reaction involving proton-coupled electron transfer occurred on the surface of N2CV-CN. Furthermore, by integrating photocatalysis with flocculation, about 99.1 % suspended substance, 45.5 % chemical oxygen demand, and 38.4 % biological oxygen demand were reduced from polluted river-water. Constructing N2CV-CN and understanding its crucial role offer theoretical and methodological insights into the in-situ purification of contaminated water bodies.

Composition of heavy metals in sediment, water, and fish of the Ganga and Yamuna Rivers in two major cities of India.

The rapid industrial development in the Indian capital region has led to significant waste generation, which, despite undergoing treatment prior to disposal, contributes substantially to water body contamination. Given the diverse nature of these wastes and their potential repercussions across the food chain, a study was conducted to evaluate heavy metal contamination levels in the Ganga and Yamuna Rivers of two major cities. Six heavy metals (Pb, Cd, Hg, Cu, Cr, and Zn) were analyzed in fish, water, and sediment samples by utilizing flame atomic absorption spectrophotometry (Avanta Σ) from March 2019 to February 2020. Results revealed distinct heavy metal distribution patterns, with Cr > Zn > Pb > Cu > Cd > Hg in the Ganga River and Zn > Cr > Pb > Cu > Cd > Hg in the Yamuna River for fish samples. Additionally, levels of Hg in Cyprinus carpio and Sperata oar from the Ganga River, and Pb, Cd, Hg, and Cr in Salmophasia bacaila and Mystus cavasius from the Yamuna River exceeded WHO/FAO permissible limits. In water samples, the predominant heavy metal sequences were Pb > Cu > Zn > Cr > Cd > Hg for the Ganga River and Cr > Zn > Pb > Cu > Cd > Hg for the Yamuna River, with Pb, Cr, Zn, and Cd surpassing WHO standards. Sediment analysis revealed varying heavy metal compositions, with Zn > Cr > Pb > Cu > Cd > Hg in the Ganga River and Cr > Zn > Pb > Cu > Cd > Hg in the Yamuna River. While drinking water and fish from the Ganga River were deemed safe for consumption, those from the Yamuna River were not. Given the toxic nature of heavy metals and their detrimental health impacts, regular monitoring and effective management strategies are imperative.

Mitigating water pollution by nitrogen fertilizers through amending ammonium sorption in an acid soil using Calciprill and sodium silicate

Use of nitrogen (N) fertilizers is gaining popularity to meet crop nutrient requirement for sustaining the food security of the increasing global population. However, improper management of N fertilizers in acid soils causes leaching and surface runoff because of excessive rainfalls and poor N retention in the tropics in particular. This results in N pollution in water bodies (also known as eutrophication), which degrades water quality to the detriment of aquatic ecosystems near farms. Thus, there is a need for using inorganic soil amendments such as Calciprill and sodium silicate to improve soil N adsorption because of the alkalinity and ability of these amendments to retain N for mitigating excessive N contamination in water bodies. To this end, this N sorption study was conducted to determine the effects of Calciprill and sodium silicate on ammonium (NH4+) adsorption and desorption in an acid soil (Bekenu series, Typic Paleudults). The soil was co-applied with different rates of Calciprill (80 %, 90 %, and 100 % Ca saturations) and sodium silicate (90, 105, 120, 135, and 150 kg ha−1), followed by the NH4+ adsorption capacity determination through the additions of NH4+ isonormal solutions at the five concentrations (0, 25, 50, 75, and 100 mg L−1) to establish a linear relationship between the amount of NH4+ absorbed (qe) and the amount of NH4+ left in the solution (Ce) after 24 h of equilibration. Apart from the soil only without any amendment (C0S0), there were another two additional treatments where the soil was added with Calciprill (100 % Ca saturation) (C3) and sodium silicate only (150 kg ha−1) (S5) to determine their respectively effects on N sorption. The collected data were fitted to the Langmuir and Freundlich isotherms. Thereafter, NH4+ desorption was determined using the same soil samples added with 2 mol dm−3. Compared with the soil without any amendment (C0S0), the Calcirpill alone (C3) and the combined use of Calciprill and sodium silicate significantly increased NH4+ adsorption at the NH4+ addition of 250 mg L̶1, suggesting that Calciprill is the amendment which dominantly increases NH4+ adsorption and the effects of amendments are more pronounced at the lower soil NH4+ concentration. The results also revealed that the NH4+ adsorption in the soils following the co-application of Calciprill and sodium silicate followed the assumption of Freundlich isotherm. Regardless of the NH4+ concentration used, the effects of Calciprill and sodium silicate on the NH4+ desorption remain unclear, which could be because of the ability of sodium silicate to stabilize the soil structure. This stabilization reaction might have impeded the dissolution of Calciprill and temporarily fixed the absorbed NH4+. These findings suggest that it is possible to use the amendments to amend NH4+ sorption in Bekenu series for mitigating NH4+ leaching and runoff to prevent eutrophication.

Oxidation of imidacloprid insecticide through PMS activation using CuFe2O4 nanoparticles: Role of process parameters and surface modifications

The contamination of water bodies by synthetic organic compounds coupled with climate change and the growing demand for water supply calls for new approaches to water management and treatment. To tackle the decontamination issue, the activation of peroxymonosulfate (PMS) using copper magnetic ferrite (CuMF) nanoparticles prepared under distinct synthesis conditions was assessed to oxidize imidacloprid (IMD) insecticide. After optimization of some operational variables, such as CuMF load (62.5–250 mg L−1), PMS concentration (250–1000 μM), and solution pH (3-10), IMD was completely oxidized in 2 h without interferences from leached metal ions. Such performance was also achieved when using tap water but was inhibited by a simulated municipal wastewater due to scavenging effects promoted by inorganic and organic species. Although there was evidence of the presence of sulfate radicals and singlet oxygen oxidizing species, only four intermediate compounds were detected by liquid chromatography coupled to mass spectrometry analysis, mainly due to hydroxyl addition reactions. Concerning the changes in surface properties of CuMF after use, no morphological or structural changes were observed except a small increase in the charge transfer resistance. Based on the changes of terminal surface groups, PMS activation occurred on Fe sites.

Unlocking the Power of Solar Synergy: Enhanced Nitrophenol Degradation using ADGCAAQ Photocatalyst

The remarkable mechanical and chemical characteristics of graphene have garnered significant interest in scientific investigations aimed at addressing severe environmental problems and energy shortages. A concerning problem is the careless disposal of industrial wastes that contain a variety of organic contaminants in water bodies. In order to create the ADGCAAQ light harvesting photocatalyst, a simple and extremely effective condensation process involving 1, 4-diamino anthraquinone (AAQ) and graphene generated from aloe vera (ADG) has been urbanized. Several approaches are used to analyze the newly constructed photocatalyst, indicating that it has the requisite potential to degrade 4-nitrophenol. By analyzing the degradation rate and order reaction of the degradation process, the kinetics of the degradation route have been used to analyze the mechanistic pathway for the degradation of 4-nitrophenol using a reducing agent and the ADGCAAQ photocatalyst. Under outside solar spectrum conditions, the photocatalytic activity of ADGCAAQ photocatalyst tested with 4-nitrophenol shows significant degradation efficiency with reducing agent H2O2.

Eco-Engineered Low-Cost Carbosorbent Derived from Biodegradable Domestic Waste for Efficient Total Chromium Removal from Aqueous Environment: Spectroscopic and Adsorption Study

Chromium contamination in water bodies poses severe risks to both the environment and human health. This research introduces an innovative solution to this challenge by creating a vapor-activated carbosorbent from biodegradable household waste. The efficacy of this adsorbent in removing total chromium through batch methods from aqueous solutions was investigated. Surface analysis using scanning electron microscopy (SEM) exhibited a porous structure, while Fourier-transform infrared spectroscopy (FTIR) identified distinct functional groups on the surface. The point of zero charge (PZC), determined at 6.95, revealed the adsorbent’s surface chemistry. Impressively, the synthesized carbosorbent exhibited significant adsorption capacities of 23.08 mg.g-1 for Cr(III) and 24.84 mg.g-1 for Cr(VI) under optimal conditions. The Langmuir isotherm model illustrated a monolayer adsorption mechanism aligned with the pseudo-second-order kinetic model, confirming chemisorption. Thermodynamic analysis disclosed favorable and spontaneous chromium adsorption. Negative ΔG° values affirmed the spontaneity, while the exothermic nature of the process was signified by the positive ΔH° value, indicating heat release. Increased randomness at the solid-liquid interface, indicated by the positive ΔS° value, underscored the enhanced affinity between the adsorbent and adsorbate. This study exemplifies the potential of the vapor-activated carbosorbent as an efficient and sustainable remedy for chromium-contaminated water bodies.

Sustainable Napier Grass (Pennisetum purpureum) Biochar for the Sorptive Removal of Acid Orange 7 (AO7) from Water

The unregulated discharge of synthetic dyes from various anthropogenic and industrial activities has resulted in the contamination of different environmental compartments. These dyes can contaminate water bodies, soil, and even the air, resulting in many environmental and health issues. True colors may persist for long periods, thereby affecting the aesthetics and ecology of dye-contaminated areas. Furthermore, they pose potential risks to aquatic life and human health through the ingestion or absorption of dye-contaminated water or food. Acid orange 7 (AO7) is a synthetic azo dye used in the textile, tanning, food, pharmaceutical, paint, electronics, cosmetics, and paper and pulp industries. AO7 can have various human health implications, such as dermatitis, nausea, severe headache, respiratory tract irritation, and bone marrow depletion, due to its high toxicity, mutagenicity, and carcinogenicity. Efforts to regulate and mitigate dye pollution (AO7) are crucial for environmental sustainability and public health. Therefore, this study aimed to remove AO7 from water using sustainable biochar. This objective was accomplished by pyrolyzing dried Napier grass at 700 °C to develop affordable and sustainable Napier grass biochar (NGBC700). The developed biochar was characterized for its surface morphology, surface functional groups, surface area, and elemental composition. The yield, moisture content, and ash content of the NGBC700 were approximately 31%, 6%, and 21%, respectively. The NGBC700’s BET (Brunauer–Emmett–Teller) surface area was 108 . Batch sorption studies were carried out at different pH levels (2–10), biochar dosages (1, 2, 3, and 4 ), and AO7 concentrations (10, 20, and 30 . The kinetic data were better fitted to the pseudo-second-order (PSO) equation (R2 = 0.964–0.997) than the pseudo-first-order (PFO) equation (R2 = 0.789–0.988). The Freundlich isotherm equation (R2 = 0.965–0.994) fitted the sorption equilibrium data better than the Langmuir equation (R2 = 0.788–0.987), suggesting AO7 sorption on heterogenous NGBC700. The maximum monolayer AO7 adsorption capacities of the NGBC700 were 14.3, 12.7, and 8.4 at 10, 25, and 40 °C, respectively. The column AO7 sorption capacity was 4.4. Fixed-bed AO7 sorption data were fitted to the Thomas and Yoon–Nelson column models. The NGBC700 efficiently removed AO7 from locally available dye-laden wastewater. NGBC700 was regenerated using different NaOH concentrations. Possible interactions contributing to AO7 sorption on NGBC700 include hydrogen bonding, electrostatic interactions, and π–π electron donor–acceptor attractions. The estimated total preparation cost of NGBC700 was US$ 6.02 kg−1. The developed sustainable NGBC700 is potentially cost-effective and environmentally friendly, and it utilizes waste (Napier grass) to eliminate fatal AO7 dye from aqueous media.

Amphiphilic N-halamine copolymer antibacterial nanoparticles with hydrogen-donor and hydrogen-acceptor

Bacterial contamination in water bodies is potentially transmissible to humans, making water bodies a major pathway of bacterial transmission. However, existing hydantoin copolymer nanoparticles did not achieve the regulation of nanoparticle dispersion and particle size by adjusting the ratio of hydrogen-donors and hydrogen-acceptors. To tackle this issue, amphiphilic hydantoin copolymer nanoparticles (P(VBDH-BA-NVP)NPs) were synthesized by modulating hydrogen-donors and hydrogen-acceptors using emulsion polymerization, and amphiphilic N-halamine copolymer nanoparticles (P(ClV-BA-NVP)NPs) were subsequently prepared via chlorination treatment. Impressively, nanoparticle dispersion and particle size were modulated by adjusting the ratio of hydrogen-donors and hydrogen-acceptors. With the increase of nanoparticle dispersion and the decrease of particle size, the active chlorine content was gradually enlarged, and the antibacterial performance was progressively enhanced against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). More importantly, amphiphilic N-halamine copolymer nanoparticles with two-dimensional dispersing (2DD-P(ClV-BA-NVP)NPs) exhibited excellent antibacterial properties, which benefited from the dual coordination of direct contact killing and indirect release killing in aqueous medium. Through designing P(VBDH-BA-NVP)NPs with hydrogen bond interactions, this approach aims to achieve the constitutive relationship between the effective exposure of active sites and the antibacterial effect.

A Review of Recent Developments on Modeling Low Impact Development (LID) Technique

Urban areas are more susceptible to flooding and water body contamination due to the detrimental effects of urbanization. As a result, a sustainable urban drainage system, also known as low impact development (LID) technique, is required. Although this technique can be extensively applied, the planning and design processes are multi-dimensional, multi-variable, and site-specific, which must consider various local conditions and factors. Consequently, these processes can be very complicated and time-consuming for professionals, necessitating support from computer modeling. This study intends to thoroughly explore the idea of LID modeling, various available computer models, and other tools for its optimization and decision-making processes. The most recent trustworthy journal publications that addressed the subjects under discussion were reviewed. This paper used the descriptive and comparative approaches as the analytical methods. According to the findings of the review, Storm Water Management Model (SWMM) is the computer model in LID modeling that is most frequently employed. This model is a fundamental package for dynamic urban rainfall-runoff modeling, and it has the benefits of being lightweight, simple to use, and an intuitive user interface. Besides, this model is public domain (free to use), open source, and interoperable with many hydro modeling applications. A specific LID editor module is also included in this model for modeling different LID units. To acquire the best LID planning and design from multiple criteria and alternatives, it is also necessary to use metaheuristic algorithms as an optimization model and a multi-criteria decision-making (MCDM) model in addition to the rainfall-runoff model. The authors believe combining the hydrologic and hydraulics models integrated with geographical information systems (GIS), metaheuristic algorithms, and MCDM is the most comprehensive and appropriate method for LID modeling in urban watersheds.

Accessing the Potential of Bismuth Oxide Nanosheets for an incredible revelation in the removal of contamination in water bodies

<p>Water contamination is a pressing global issue with far-reaching environmental, health, and socio-economic consequences. As the demand for clean water intensifies, researchers are exploring innovative nanomaterials to develop efficient and sustainable water treatment technologies. The Bismuth oxide (Bi2O3) nanosheets were synthesized using a sustainable approach comprising Moringa oleifera seed extract as a biological capping and reducing agent. Analytical techniques were utilized to inspect the prepared nanosheets' crystalline, morphological, and optical characteristics. The optical properties, including light absorption and bandgap width, were investigated using UV-visible spectroscopy using a bandgap energy of 4.65 eV. In addition, the nanosheet's ability to degrade cationic malachite green and Rhodamine 6G dye and anionic eosin yellow and reactive black dyes by photocatalysis was evaluated. The degradation of cationic and anionic dyes was characterized by nanocatalysis using UV-visible spectroscopy and a pseudo-first-order kinetics model. The pseudo-first-order degradation kinetic rate of malachite green and Rhodamine 6G was determined to be 3.46 and 3.20 X 10-2 min-1, indicating that the prepared nanosheets effectively initiate this dye's degradation. The results showed dye degradation was more effective at cationic dyes than anionic dyes.</p>

Novel chitosan-modified biochar prepared from a Chinese herb residue for multiple heavy metals removal: Characterization, performance and mechanism

In this study, the sorption properties of Cr(VI), As(III), and Pb(II) on chitosan-modified magnetic biochar (CMBC) derived from residues of Ligusticum chuanxiong Hort. were investigated. CMBC was found to be a valuable material for removing three heavy metals from water simultaneously. Kinetic analysis suggested Cr(VI), As(III), and Pb(II) were chemisorbed onto CMBC, while isotherm data conformed well to Langmuir model, the maximum adsorption capacity of CMBC was found to be 65.74 mg/g for Cr(VI), 49.32 mg/g for As(III), and 69.45 mg/g for Pb(II). Experiments, characterization, and density functional theory (DFT) calculations were employed to explore the mechanisms. Furthermore, CMBC demonstrated excellent removal rates of over 95% for Cr(VI), 99% for As(III) and Pb(II) from contaminated water bodies. This work shows that CMBC holds significant potential for wastewater treatment of heavy metals and provides an effective solution for the utilization of Chinese herb residues in environmental remediation.

Comprehensive analysis of cyanobacterial secondary metabolites distribution and toxicity in urban water bodies

This study addresses the increasing concern regarding cyanotoxin contamination of water bodies, highlighting the diversity of these toxins and their potential health implications. Cyanobacteria, which are prevalent in aquatic environments, produce toxic metabolites, raising concerns regarding human exposure and associated health risks, including a potential increase in cancer risk. Although existing research has primarily focused on well-known cyanotoxins, recent technological advancements have revealed numerous unknown cyanotoxins, necessitating a comprehensive assessment of multiple toxin categories. To enhance the cyanotoxin databases, we optimized the CyanoMetDB cyanobacterial secondary metabolites database by incorporating secondary fragmentation patterns using the Mass Frontier fragmentation data prediction software. Water samples from diverse locations in Shanghai were analyzed using high-resolution mass spectrometry. Subsequently, the toxicity of cyanobacterial metabolites in the water samples was examined through acute toxicity assays using the crustacean Thamnocephalus platyurus. After 24 h of exposure, the semi-lethal concentrations (LC50) of the water samples ranged from 0.31 mg L−1 to 1.78 mg L−1 (MC-LR equivalent concentration). Our findings revealed a critical correlation between the overall concentration of cyanobacterial metabolites and toxicity. The robust framework and insights of this study underscore the need for an inclusive approach to water quality management, emphasizing continuous efforts to refine detection methods and comprehend the broader ecological impact of cyanobacterial blooms on aquatic ecosystems.