Fabrication of granular three-dimensional graphene oxide/UiO-66 adsorbent for high uranium adsorption: Density functional theory and fixed bed column studies.

This study presents a thorough investigation of the novel application of graphene oxide (GO) modified with melamine formaldehyde to fabricate granular three-dimensional GO (3D-GO), followed by the introduction of UiO-66 doping (3D-GO/U) for high uranium (U) adsorption. The U(VI) adsorption isotherms revealed that 3D-GO/U-10 with 10 % UiO-66 incorporation exhibited an impressive adsorption capacity of 375.5 mg g-1 and remained high U(VI) sorption performance in wide pH range. The introduction of UiO-66 to 3D-GO (3D-GO/U-10) led to the deagglomeration of the UiO-66 particles. The in situ surface-enhanced-Raman-spectroscopy-analysis and density-functional-theory simulations showed the symmetric metal center site Zr-O2 on UiO-66 was discovered to exhibit the highest adsorption energy (-3.21 eV) for U(VI) species due to the electrons transfer from the oxygen atom to U(VI) drives the covalent bonding between the symmetric metal center sites Zr-O2 and U(VI) on 3D-GO/U-10. The 3D-GO/U-10 was regenerated using a 0.1 M Na2CO3/0.01 M H2O2 solution and achieved up to 89.7 % U(VI) removal in the 5th cycle. The continuous flow column experiments results revealed 3D-GO/U-10 can regenerate and maintain a U(VI) removal capacity of ∼76 % for up to 4 cycles column experiments. Therefore, 3D-GO/U-10 exhibits great potential for removing U(VI) from water bodies.

Redefining water purification: gC3N4-CLDH's electrochemical SMX eradication.

The contamination of water sources by pharmaceutical compounds presents global environmental and health risks, necessitating the development of efficient water treatment technologies. In this study, the synthesis, characterization, and evaluation of a novel graphitic carbon nitride-calcined (Fe-Ca) layered double hydroxide (gC3N4-CLDH) composite for electrochemical degradation of sulfamethoxazole (SMX) in water yielded significant outcomes are reported. SEM, XRD, FTIR, and XPS analyses confirmed well-defined composite structures with unique morphology and crystalline properties. Electrochemical degradation experiments demonstrated >98% SMX removal and >75% TOC removal under optimized conditions, highlighting its effectiveness. The composite exhibited excellent mineralization efficiency across various pH levels, with superoxide radicals (O2●-) and hydroxyl radicals (●OH) identified as primary reactive oxygen species. With remarkable regeneration capability for up to 7 cycles, the gC3N4-CLDH composite emerges as a highly promising solution for sustainable water treatment. Humic acid (HA) in water significantly slows SMX degradation, suggests complicating SMX degradation with natural organic matter. Despite this, the gC3N4-CLDH composite effectively degrades SMX in groundwater and industrial wastewater, with slight efficiency reduction in the latter due to higher impurity levels. These findings highlight the complexities of treating pharmaceutical pollutants in various water types. Overall, gC3N4-CLDH's high removal efficiency, broad pH applicability, sustainability, and mechanistic insights provide a solid foundation for future research and real-world environmental applications.

Moderation of thyroid hormones for the relationship between amyloid and tau pathology.

BACKGROUND: Altered thyroid hormone levels have been associated with increased risk of Alzheimer's disease (AD) dementia and related cognitive decline. However, the neuropathological substrates underlying the link between thyroid hormones and AD dementia are not yet fully understood. We first investigated the association between serum thyroid hormone levels and in vivo AD pathologies including both beta-amyloid (Aß) and tau deposition measured by positron emission tomography (PET). Given the well-known relationship between Aß and tau pathology in AD, we additionally examined the moderating effects of thyroid hormone levels on the association between Aß and tau deposition. METHODS: This cross-sectional study was conducted as part of the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer's Disease (KBASE) cohort. This study included a total of 291 cognitively normal adults aged 55 to 90. All participants received comprehensive clinical assessments, measurements for serum total triiodothyronine (T3), free triiodothyronine (fT3), free thyroxine (fT4), and thyroid-stimulating hormone (TSH), and brain imaging evaluations including [11C]-Pittsburgh compound B (PiB)- PET and [18F] AV-1451 PET. RESULTS: No associations were found between either thyroid hormones or TSH and Aß and tau deposition on PET. However, fT4 (p = 0.002) and fT3 (p = 0.001) exhibited significant interactions with Aß on tau deposition: The sensitivity analyses conducted after the removal of an outlier showed that the interaction effect between fT4 and Aß deposition was not significant, whereas the interaction between fT3 and Aß deposition remained significant. However, further subgroup analyses demonstrated a more pronounced positive relationship between Aß and tau in both the higher fT4 and fT3 groups compared to the lower group, irrespective of outlier removal. Meanwhile, neither T3 nor TSH had any interaction with Aß on tau deposition. CONCLUSION: Our findings suggest that serum thyroid hormones may moderate the relationship between cerebral Aß and tau pathology. Higher levels of serum thyroid hormones could potentially accelerate the Aß-dependent tau deposition in the brain. Further replication studies in independent samples are needed to verify the current results.

Analyzing atmospheric plasma's potential for diesel soil remediation: Insightful mechanisms.

The remediation of diesel-contaminated soil is a critical environmental concern, driving the need for effective solutions. Recently, the methodology of Non-thermal Atmospheric Plasma (NTAP) technology, which is equipped with a Dielectric Barrier Discharge (DBD) electrode and has become a feasible approach, was proven to be viable. The reactive species from the plasma were exposed to the contaminated soil in this investigation using the NTAP technique. The reacted soil was then extracted using dichloromethane, and the amount of Total Petroleum Hydrocarbon (TPH) removed was assessed. Investigation into varying power levels, treatment durations, and hydrogen peroxide integration revealed significant findings. With an initial concentration of 3086 mg of diesel/kg of soil and a pH of 5.0, 83% of the diesel was removed from the soil at 150 W in under 20 min. Extended exposure to NTAP further improved removal rates, highlighting the importance of treatment duration optimization. Additionally, combining hydrogen peroxide (H2O2) with NTAP enhanced removal efficiency by facilitating diesel breakdown. This synergy offers a promising avenue for comprehensive soil decontamination. Further analysis considered the impact of soil characteristics on removal efficacy. Mechanistically, NTAP generates reactive species that degrade diesel into less harmful compounds, aiding subsequent removal. Overall, NTAP advances environmental restoration efforts by offering a quick, economical, and environmentally benign method of remediating diesel-contaminated soil especially when used in tandem with hydrogen peroxide.

Plasma Leptin and Alzheimer Protein Pathologies Among Older Adults.

Importance: Many epidemiologic studies have suggested that low levels of plasma leptin, a major adipokine, are associated with increased risk of Alzheimer disease (AD) dementia and cognitive decline. Nevertheless, the mechanistic pathway linking plasma leptin and AD-related cognitive decline is not yet fully understood. Objective: To examine the association of plasma leptin levels with in vivo AD pathologies, including amyloid-beta (Aß) and tau deposition, through both cross-sectional and longitudinal approaches among cognitively unimpaired older adults. Design, Setting, and Participants: This was a longitudinal cohort study from the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer Disease. Data were collected from January 1, 2014, to December 31, 2020, and data were analyzed from July 11 to September 6, 2022. The study included a total of 208 cognitively unimpaired participants who underwent baseline positron emission tomography (PET) scans for brain Aß deposition. For longitudinal analyses, 192 participants who completed both baseline and 2-year follow-up PET scans for brain Aß deposition were included. Exposure: Plasma leptin levels as assessed by enzyme-linked immunosorbent assay. Main Outcomes and Measures: Baseline levels and longitudinal changes of global Aß and AD-signature region tau deposition measured by PET scans. Results: Among the 208 participants, the mean (SD) age was 66.0 (11.3) years, 114 were women (54.8%), and 37 were apolipoprotein E ε4 carriers (17.8%). Lower plasma leptin levels had a significant cross-sectional association with greater brain Aß deposition (ß = -0.04; 95% CI, -0.09 to 0.00; P = .046), while there was no significant association between plasma leptin levels and tau deposition (ß = -0.02; 95% CI, -0.05 to 0.02; P = .41). In contrast, longitudinal analyses revealed that there was a significant association between lower baseline leptin levels and greater increase of tau deposition over 2 years (ß = -0.06; 95% CI, -0.11 to -0.01; P = .03), whereas plasma leptin levels did not have a significant association with longitudinal change of Aß deposition (ß = 0.006; 95% CI, 0.00-0.02; P = .27). Conclusions and Relevance: The present findings suggest that plasma leptin may be protective for the development or progression of AD pathology, including both Aß and tau deposition.

Association between brain amyloid deposition and longitudinal changes of white matter hyperintensities.

BACKGROUND: Growing evidence suggests that not only cerebrovascular disease but also Alzheimer's disease (AD) pathological process itself cause cerebral white matter degeneration, resulting in white matter hyperintensities (WMHs). Some preclinical evidence also indicates that white matter degeneration may precede or affect the development of AD pathology. This study aimed to clarify the direction of influence between in vivo AD pathologies, particularly beta-amyloid (Aß) and tau deposition, and WMHs through longitudinal approach. METHODS: Total 282 older adults including cognitively normal and cognitively impaired individuals were recruited from the Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease (KBASE) cohort. The participants underwent comprehensive clinical and neuropsychological assessment, [11C] Pittsburgh Compound B PET for measuring Aß deposition, [18F] AV-1451 PET for measuring tau deposition, and MRI scans with fluid-attenuated inversion recovery image for measuring WMH volume. The relationships between Aß or tau deposition and WMH volume were examined using multiple linear regression analysis. In this analysis, baseline Aß or tau were used as independent variables, and change of WMH volume over 2 years was used as dependent variable to examine the effect of AD pathology on increase of WMH volume. Additionally, we set baseline WMH volume as independent variable and longitudinal change of Aß or tau deposition for 2 years as dependent variables to investigate whether WMH volume could precede AD pathologies. RESULTS: Baseline Aß deposition, but not tau deposition, had significant positive association with longitudinal change of WMH volume over 2 years. Baseline WMH volume was not related with any of longitudinal change of Aß or tau deposition for 2 years. We also found a significant interaction effect between baseline Aß deposition and sex on longitudinal change of WMH volume. Subsequent subgroup analyses showed that high baseline Aß deposition was associated with increase of WMH volume over 2 years in female, but not in male. CONCLUSIONS: Our findings suggest that Aß deposition accelerates cerebral WMHs, particularly in female, whereas white matter degeneration appears not influence on longitudinal Aß increase. The results also did not support any direction of influence between tau deposition and WMHs.

Exploring recyclable alginate-enhanced GCN-LDO sponge for U(VI) and Cd(II) removal: Insights from batch and column studies.

Developing effective water treatment materials, particularly through proven adsorption methods, is crucial for removing heavy metal contaminants. This study synthesizes a cost-effective three-dimensional material encapsulating graphitic carbon nitride-layered double oxide (GCN-LDO) in sodium alginate (SA) through the freeze-drying method. The material is applied to remove uranium (U(VI)) and cadmium (Cd(II)) in real water systems. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analyses conclusively verified the elemental composition and successful encapsulation of GCN-LDO within the SA matrix. Removal effectiveness was tested under various conditions, including adsorbent dose, ionic strength, contact time, temperature, different initial pollutant concentrations, and the impact of co-existing ions. The adsorption of U(VI) and Cd(II) conformed to the pseudo-second-order (PSO) kinetic model, signifying a chemical interaction between the sodium alginate-graphitic carbon nitride-layered double oxide (SA-GCN-LDO) sponge and the metal ions. The Langmuir isotherm indicated monolayer, homogeneous adsorption for U(VI) and Cd(II) with capacities of 158.25 and 165.00 mg/g. SA-GCN-LDO recyclability was found in up to seven adsorption cycles with a removal efficacy of 70%. The temperature effect study depicts the exothermic nature of the U(VI) and Cd(II) ion removal process. Various mechanisms involved in U(VI) and Cd(II) removal were proposed. Further, continuous fixed bed column studies were performed, and Thomas and the Yoon-Nelson model were studied. These insights from this investigation contribute to advancing our knowledge of the material's performance within the context of U(VI) and Cd(II) adsorption, paving the way for optimized and sustainable water treatment solutions.

Improving U(VI) retention efficiency and cycling stability of GCN-supported calcined-LDH composite: Mechanism insight and real water system applications.

The synthesis and characterization of graphitic carbon nitride (GCN) and its composites with calcined layered double hydroxide (CLDH) were examined in this investigation. The goal was to assess these composites' maximum adsorption capacity (qmax) for U(VI) ions in wastewater. Several different characterization methodologies were utilized to examine the fabricated substances. These methods encompass X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The GCN-CLDH composite displayed enhanced adsorption ability towards U(VI) ions due to its high surface functionality. Langmuir adsorption isotherm analysis showed that more than 99% of U(VI) ions were adsorbed, with a qmax of 196.69 mg/g. The kinetics data exhibited a good fit for a pseudo-second-order (PSO) model. Adsorption mechanisms involving precipitation and surface complexation via Lewis's acid-base interactions were proposed. The application of the GCN-CLDH composite in groundwater demonstrated adsorption below the maximum permissible limit established by USEPA, indicating improved cycling stability. These observations underscore the capacity of the GCN-CLDH composite's proficiency in adsorbing U(VI) aqueous solutions containing radioactive metals.

Insights into kinetics, thermodynamics, and mechanisms of chemically activated sunflower stem biochar for removal of phenol and bisphenol-A from wastewater.

This study synthesized a highly efficient KOH-treated sunflower stem activated carbon (KOH-SSAC) using a two-step pyrolysis process and chemical activation using KOH. The resulting material exhibited exceptional properties, such as a high specific surface area (452 m2/g) and excellent adsorption capacities for phenol (333.03 mg/g) and bisphenol A (BPA) (365.81 mg/g). The adsorption process was spontaneous and exothermic, benefiting from the synergistic effects of hydrogen bonding, electrostatic attraction, and stacking interactions. Comparative analysis also showed that KOH-SSAC performed approximately twice as well as sunflower stem biochar (SSB), indicating its potential for water treatment and pollutant removal applications. The study suggests the exploration of optimization strategies to further enhance the efficiency of KOH-SSAC in large-scale scenarios. These findings contribute to the development of improved materials for efficient water treatment and pollution control.

Development of ultra-high surface area polyaniline-based activated carbon for the removal of volatile organic compounds from industrial effluents.

Removing volatile organic compounds (VOCs) from aqueous solutions is critical for reducing VOC emissions in the environment. Activated carbons are widely used for removal of VOCs from water. However, they show less application feasibility and low removal due to less surface area. Here, a cost-effective and high surface area activated carbonized polyaniline (ACP) was synthesized to sustainable removal of VOCs from water. The ACP microstructure, surface properties, and pore structure were investigated using Brunauer-Emmett-Teller (BET) theory, Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The specific surface area of ACP6:1 (2988.13 m2/g) was greater than that of commercial activated carbon (PAC) (1094.49 m2/g), indicating that it has excellent VOC adsorption capacity. The effects of pH, initial VOC concentration, time, temperature, and ionic strength were studied. According to kinetic and thermodynamic studies on VOCs adsorption, it is an exothermic and spontaneous process involving rate-limiting kinetics. Adsorption isotherms follow the Freundlich isotherm model, suggesting that the adsorbent surface is heterogeneous with multilayer adsorption and maximum ACP adsorption capacities of 1913.9, 2453.3, 1635.8, and 3327.0 mg/g at 293 K for benzene, toluene, ethylbenzene, and perchloroethylene, respectively, representing a 3- to 5-fold improvement over PAC. ACP is a promising adsorbent with a high adsorption efficiency for VOC removal.

Efficiency of Ppy-PA-pani and Ppy-PA composite adsorbents in Chromium(VI) removal from aqueous solution.

In this study, first time the combination of composites with Phytic acid (PA) as the organic binder cross-linker is reported. The novel use of PA with single and double conducting polymers (polypyrrole (Ppy) and polyaniline (Pani)) were tested against removal of Cr(VI) from wastewater. Characterizations (FE-SEM, EDX, FTIR, XRD, XPS) were performed to study the morphology and removal mechanism. The adsorption removal capability of Polypyrrole - Phytic Acid - Polyaniline (Ppy-PA-Pani) was deemed to be higher than Polypyrrole - Phytic Acid (Ppy-PA) due to the mere existence of Polyaniline as the extra polymer. The kinetics followed 2nd order with equilibration at 480 min, but Elovich model confirmed that chemisorption is followed. Langmuir isotherm model exhibited maximum adsorption capacity of 222.7-321.49 mg/g for Ppy-PA-Pani and 207.66-271.96 mg/g for Ppy-PA at 298K-318K with R2 values of 0.9934 and 0.9938 respectively. The adsorbents were reusable for 5 cycles of adsorption-desorption. The thermodynamic parameter, ΔH shows positive values confirmed the adsorption process was endothermic. From overall results, the removal mechanism is believed to be chemisorption through Cr(VI) reduction to Cr(III). The use of phytic acid (PA) as organic binder with combination of dual conducting polymer (Ppy-PA-Pani) was invigorating the adsorption efficiency than just single conducting polymer (Ppy-PA).

Insights into manganese ferrite anchored graphene oxide to remove Cd(II) and U(VI) via batch and semi-batch columns and its potential antibacterial applications.

The bioaccumulation, non-biodegradability, and high toxicity of Cd(II) and U(VI) in water is a serious concerns. Manganese ferrite/graphene oxide (GMF) nanocomposites were synthesized, characterized, and used to efficiently remove Cd(II) and U(VI) from an aqueous solution in this study. X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS) analyses, respectively, confirmed the formation of GMF and the adsorptive removal mechanism. The XRD results revealed an amorphous structure when MnFe2O4 was loaded onto the GO surface. XPS results suggest that C = C, C-OorOH, and metal oxides are responsible for the removal of Cd(II) and U(VI) via electrostatic and chemical interaction. According to the Brunauer Emmett and Teller (BET), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) characterization analysis, GMF has a high surface area (117.78 m2/g) and a spherical shape with even distribution. The kinetics data were successfully reproduced by a pseudo-second-order non-linear model indicating the complexity of the sorption mechanism was rate-limiting. The maximum Langmuir uptake ability of GMF for Cd(II) and U(VI) was calculated to be 232.56 mg/g and 201.65 mg/g, respectively. Using external magnetic power, the prepared GMF can easily separate from the aqueous solution and can keep both metal ions under Environmental protection agency standards in water for up to six cycles of re-use of GMF. Finally, the GMF nanocomposite demonstrated significant promise as an adsorbent for removing Cd(II) and U(VI) from actual contaminated water samples. The antibacterial test was expanded to include gram-negative E. coli and gram-positive S. aureus to better understand GMF's bacterial inhibition efficacy.

Stable and recyclable lanthanum hydroxide-doped graphene oxide biopolymer foam for superior aqueous arsenate removal: Insight mechanisms, batch, and column studies.

In this study, a graphene oxide-based lanthanum hydroxide/chitosan foam (CSGOL foam) was synthesized for arsenate (As(V)) remediation in surface water. The synthesized CSGOL foam texture and purity was assessed using scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) studies. The results proved that the foam was highly porous, stable, and had high surface functionality that facilitated adsorption for water pollutant removal. The sorption results proved that the As(V) removal was high (146.20 mg/g at pH 6 with 0.5 g/L CSGOL foam) when compared to the similar type of materials, endothermic chemisorption due to the production of monodentate and bidentate inner-sphere complexes. Furthermore, continuous column results indicated that the As(V) concentration in real surface waters was reduced to WHO standards (less than 10 µg As/L of water) of As(V) in drinking water for up to 10,000 bed volume. Further it can be used up to four cycles without loss of efficacy less than 93%. Because of its excellent removal capabilities and simple synthesis technique, CSGOL foam shows significant promise for treating As(V)-containing water. Further, the XPS analysis and batch studies results suggests that As(V) removal mechanism was involved electrostatic and surface complexation through chemical interaction predominately.

Association of low meal frequency with decreased in vivo Alzheimer's pathology.

Little is known about the association between meal frequency and Alzheimer's disease (AD) in humans. We tested the hypothesis that low meal frequency (LMF) is associated with reduced in vivo AD pathology in human brain, and additionally investigated the mediation of serum ghrelin, a hunger-related hormone, for the association. A total of 411 non-demented older adults were systematically interviewed to identify their dietary patterns including meal frequency and underwent multi-modal neuroimaging for cerebral beta-amyloid (Aß) and tau deposition, glucose metabolism, and cerebrovascular injury. LMF (less than three meals a day) was significantly associated with lower Aß deposition compared to high meal frequency (HMF). In addition, both LMF and reduced Aß deposition were significantly related to elevated serum ghrelin. Our findings suggest that LMF may be related to the lower risk of AD through reduced brain amyloid deposition. Additionally, ghrelin appears mediate the association between LMF and lower amyloid deposition.

Experimentally and spectroscopically evidenced mechanistic study of butyl peroxyacid oxidative degradation of benzo[a]pyrene in soil.

Benzo[a]pyrene (BaP) is a major indicator of soil contamination and categorized as a highly persistent, carcinogenic, and mutagenic polycyclic aromatic hydrocarbon. An advanced peroxyacid oxidation process was developed to reduce soil pollution caused by BaP originating from creosote spills from railroad sleepers. The pH, organic matter, particle size distribution of soil, and concentrations of BaP and heavy metals (Cd, Cu, Zn, Pb, and As) in the BaP-contaminated soils were estimated. A batch experiment was conducted to determine the effects of organic acid type, soil particle size, stirring speed, and reaction time on the peroxyacid oxidation of BaP in the soil samples. Additionally, the effect of the organic acid concentration on the peroxyacid degradation of BaP was investigated using an oxidizing agent in spiked soil with and without hydrogen peroxide. The results of the oxidation process indicated that BaP and heavy metal residuals were below acceptable Korean standards. A significant difference in the oxidative degradation of BaP was observed between the spiked and natural soil samples. The formation of a peroxyacid intermediate was primarily responsible for the enhanced BaP oxidation. Further, butyric acid could be reused thrice without losing the efficacy (<90%). The systematic peroxyacid oxidative degradation mechanism of BaP was also discussed. A qualitative analysis of the by-products of the BaP reaction was conducted, and their corresponding toxicities were determined for possible field applications. The findings conclude that the developed peroxyacid oxidation method has potential applications in the treatment of BaP-contaminated soils.

Highly efficient surface sequestration of Pb2+ and Cr3+ from water using a Mn3O4 anchored reduced graphene oxide: Selective removal of Pb2+ from real water.

Owing to the ubiquitous existence of detrimental heavy metals in the environment, simple adsorption-oriented approaches are becoming increasingly appealing for the effective removal of Pb2+ and Cr3+ from water bodies. These techniques use nanocomposites (NC) of reduced graphene oxide (rGO) and Mn3O4 (rGO-Mn3O4), they employ a hydrothermal technique featuring NaBH4 and NaOH solutions. Here, spectroscopic and microscopic instrumental techniques were used to evaluate the morphological and physicochemical characteristics of prepared reduced graphene oxide manganese oxide (rGO-Mn3O4), revealing that it possessed a well-defined porous structure with a specific surface area of 126 m2 g-1. The prepared rGO-Mn3O4 had significant adsorption efficiencies for Pb2+ and Cr3+, achieving maximum sequestration capacities of 130.28 and 138.51 mg g-1 for Pb2+ and Cr3+, respectively, according to the Langmuir model. These adsorption capacities are comparable to or greater than those of previously reported graphene-based materials. The Langmuir isotherm and pseudo-second-order models adequately represented the experimental results. Thermodynamic analysis revealed that adsorption occurred through spontaneous endothermic reactions. Recycling studies showed that the developed r-GO-Mn3O4 had excellent recyclability, with <70% removal at the 5th cycle; its feasibility was evaluated using industrial wastewater, suggesting that Pb2+ was selectively removed from Pb2+ and Cr3+ contaminated water. The instrumental analysis and surface phenomena studies presented here revealed that the adsorptive removal processes of both heavy metals involved π electron donor-acceptor interactions, ion exchange, and electrostatic interactions, along with surface complexation. Overall, the developed rGO-Mn3O4 has the potential to be a high-value adsorbent for removing heavy metals.

Portable SA/CMC entrapped bimetallic magnetic fly ash zeolite spheres for heavy metals contaminated industrial effluents treatment via batch and column studies.

Heavy metals are perceived as a significant environmental concern because of their toxic effect, bioaccumulation, and persistence. In this work, a novel sodium alginate (SA) and carboxymethylcellulose (CMC) entrapped with fly ash derived zeolite stabilized nano zero-valent iron and nickel (ZFN) (SA/CMC-ZFN), followed by crosslinking with CaCl2, is synthesized and applied for remediation of Cu(II) and Cr(VI) from industrial effluent. The characterization of the adsorbent and its surface mechanism for removing metals were investigated using advanced instrumental techniques, including XRD, FT-IR, SEM-EDX, BET, and XPS. The outcomes from the batch experiments indicated that monolayer adsorption on homogeneous surfaces (Langmuir isotherm model) was the rate-limiting step in both heavy metals sorption processes. The maximum adsorption capacity of as-prepared SA/CMC-ZFN was 63.29 and 10.15 mg/g for Cu(II) and Cr(VI), respectively. Owing to the fact that the wastewater released from industries are large and continuous, a continuous column is installed for simultaneous removal of heavy metal ions from real industrial wastewater. The outcomes revealed the potential of SA/CMC-ZFN as an efficient adsorbent. The experimental breakthrough curves fitted well with the theoretical values of Thomas and Yoon-Nelson models. Overall, the results indicated that SA/CMC-ZFN is a viable, efficient, and cost-effective water treatment both interms of batch and column processes.

Predictive capability evaluation and optimization of Pb(II) removal by reduced graphene oxide-based inverse spinel nickel ferrite nanocomposite.

Pb(II) is a heavy metal that is a prominent contaminant in water contamination. Among the different pollution removal strategies, adsorption was determined to be the most effective. The adsorbent and its type determine the adsorption process's efficiency. As part of this effort, a magnetic reduced graphene oxide-based inverse spinel nickel ferrite (rGNF) nanocomposite for Pb(II) removal is synthesized, and the optimal values of the independent process variables (like initial concentration, pH, residence time, temperature, and adsorbent dosage) to achieve maximum removal efficiency are investigated using conventional response surface methodology (RSM) and artificial neural networks (ANN). The results indicate that the initial concentration, adsorbent dose, residence time, pH, and process temperature are set to 15 mg/L, 0.55 g/L, 100 min, 5, and 30 °C, respectively, the maximum removal efficiency (99.8%) can be obtained. Using the interactive effects of process variables findings, the adsorption surface mechanism was examined in relation to process factors. A data-driven quadratic equation is derived based on the ANOVA, and its predictions are compared with ANN predictions to evaluate the predictive capabilities of both approaches. The R2 values of RSM and ANN predictions are 0.979 and 0.991 respectively and confirm the superiority of the ANN approach.

Magnetic-watermelon rinds biochar for uranium-contaminated water treatment using an electromagnetic semi-batch column with removal mechanistic investigations.

Biosorption using modified biochar has been increasingly adopted for the sustainable removal of uranium-contaminated from an aqueous solution. In this research study, the facile preparation and surface characteristics of magnetized biochar derived from waste watermelon rind to treat U(VI) contaminated water were investigated. The porosity, specific surface area, adsorption capacity, reusability, and stability were effectively improved after the magnetization of biochar. The kinetics and isotherm studies found that the U(VI) adsorption was rate-limiting monolayer sorption on the homogeneous surface of magnetized watermelon rind biochar (MWBC). The maximum adsorption capacity was found to be 323.56 mg of U(VI) per g of MWBC at pH 4.0 and 293 K that was higher than that of watermelon rind biochar (WBC) (135.86 mg g-1) and other sourced biochars. The surface interaction mechanism, environmental feasibility, applicability for real-filed water treatment studied in the electromagnetic semi-batch column, and reusability of MWBC were also explored. Furthermore, salient raised the ion exchange and complexation action capacity of MWBC due to the presence of Fe oxide. The overall results indicated that MWBC was not only inexpensive and had a high removal capacity for U(VI), but it also easily enabled phase separation from an aqueous solution, with more than three times reusability at a minimum removal capacity of 99%.

Polyvinyl Alcohol Polymer Functionalized Graphene Oxide Decorated with Gadolinium Oxide for Sequestration of Radionuclides from Aqueous Medium: Characterization, Mechanism, and Environmental Feasibility Studies.

Uranium (U(VI)) and thorium (Th(IV)) ions produced by the nuclear and mining industries cause water pollution, thereby harming the environment and human health. In this study, gadolinium oxide-decorated polyvinyl alcohol-graphene oxide composite (PGO-Gd) was developed using a simple hydrothermal process to treat U(VI) and Th(IV) ions in water. The developed material was structurally characterized by highly advanced spectroscopy and microscopy techniques. The effects of pH, equilibration time and temperature on both radionuclides (U(VI) and Th(IV)) adsorption by PGO-Gd were examined. The PGO-Gd composite adsorbed both metal ions satisfactorily, with adsorption capacities of 427.50 and 455.0 mg g-1 at pH 4.0, respectively. The adsorption properties of both metal ions were found to be compatible with the Langmuir and pseudo-second-order kinetic models. Additionally, based on the thermodynamic characteristics, the adsorption was endothermic and spontaneous. Furthermore, the environmental viability of PGO-Gd and its application was demonstrated by studying its reusability in treating spiked surface water. PGO-Gd shows promise as an adsorbent in effectively removing both radionuclides from aqueous solutions.