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In this work, polyvinylidene fluoride (PVDF) intercalated CuFe layered double hydroxides (LDH) membranes were fabricated and investigated for UV-LED/persulfate degradation of methylene blue (MB), crystal violet (CV), methyl orange (MO), and Eriochrome black T (EBT) dyes from water. The PVDF-CuFe membrane exhibited improved heterogeneity, surface functionality (CuO, Fe-O, Cu-O-Fe), surface roughness, and hydrophilicity. The process parameters were optimized by response surface methodology, and maximum MB removal (100%) was achieved within 45.22-178.5 min at MB concentration (29.45-101.93 mg/L), PP concentration (0.5-2.41 g/L) and catalyst dosage (1.84-1.95 g/L). The degradation kinetics was well described by a pseudo-first-order model (R2=0.982) and fast reaction rate (0.029-0.089/min). The MB dye degradation mechanism is associated with HOâ¢/SO4â¢- reactive species generated by Fe3+/Fe2+ or Cu2+/Cu+ in PVDF-CuFe membrane and PP dissociation. The PVDF-CuFe membrane demonstrated excellent recyclability performance with a 12% reduction after five consecutive cycles. The catalytic membrane showed excellent photocatalytic degradation of crystal violet (100%), methyl orange (79%), and Eriochrome black T (60%). The results showed that UV-LED/persulfate-assisted PVDF-CuFe membranes can be used as a recyclable catalyst for the effective degradation of dye-contaminated water streams.
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Surfactant-stabilized oil-in-water emulsions are a major environmental concern due to their severe consequences for aquatic organisms and humans. Two-dimensional materials, particularly MXenes, are widely used in various applications and could be used in designing advanced membranes. The narrow interlayer spacing and intrinsic oxidation severely limit mass diffusion and induce poor stability, respectively, of MXene-based separating layers on the membrane support, rendering it challenging to use for oil-water separation. Herein, a high-performing, minimally defective MXene membrane with large d-spacing was fabricated. The d-spacing of the MXene sheets was controlled using Si-based species as the intercalating agents. The modified MXene-based membrane (ultrasonication-assisted exfoliated MXene with Si pillars) (U-MX-Si) exhibited an enlarged interlayer spacing of 11 Å, increased surface energy of 41 mJ·m-2, and less defective separating layer compared to that of pristine MXene, which was due to enhanced interlayer spacing. This phenomenon induced a higher degree of exfoliated sheets that facilitated better MXene sheet self-assembly on the membrane support, thereby resulting in high separation efficiency (99%). An increase in the surface energy of the U-MX-Si membrane caused a constant permeate flux during operation, which demonstrated their practical implications. This study presents an important pathway for designing MXene-based membranes for separation applications.
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The presence of emerging organic micropollutants (OMPs) in drinking and potable waters is a matter of great concern due to the health hazards associated with these. In this work, we present the preparation and application of a thin-film nanocomposite (TFN) membrane containing functionalized graphene oxide to effectively remove low-molecular-weight OMPs from water. Graphene oxide was functionalized with amino silane to enhance its cross-linking capability during the formation of the polyamide active layer via interfacial polymerization of diethylene triamine and trimesoyl chloride. The TEM analysis showed that amino silane functionalized GO had 2-3 layered sheets, while non-functionalized graphene oxide appeared multilayered or stacked. XPS analysis confirmed the successful functionalization of GO. Characterization of the membranes with advanced techniques confirmed the successful incorporation of the GO and its functionalization: spectra from Fourier Transform Infra Red spectroscopy had the characteristic peaks of GO and NH groups; scanning Electron Microscopy (SEM) images showed a continuous presence of GO nanosheets. Contact angle measurements showed the TFN membranes to be more hydrophilic than their thin film composite (TFC) counterparts. Incorporating functionalized oxide nanosheets in the active polyamide layer produced additional water permeation channels, resulting in an improvement of â¼25 % in permeate flux compared to the pristine TFC and the TFN membrane with non-functionalized GO. The removal efficiencies of four OMPs commonly found in natural waters: Amitriptylene HCl (ATT HCl) and Bisphenol-A (BPA), Acetaminophen (ACT), and Caffeine (CFN) were determined for the synthesized membranes. The TFN membrane with functionalized GO outperformed its TFC counterpart with â¼100 % removal for BPA, â¼ 90 % for CFN and ATT HCl, and â¼80 % removal for the low molecular weight ACT. The high-efficiency rejection of OMPs was attributed to the synergistic effects of size exclusion as well as the reduced specific interactions between the functional groups.
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Objective: To compare the volume of sphenoid sinus with protrusions of optic nerve and internal carotid artery in both males and females. METHODS: The cross-sectional study was conducted from October 2020 to February 2021 at the Radiology Department of Dow University of Health Sciences, Karachi, and comprised males and females aged 20-60 years having no sphenoid sinus bony abnormality. Sphenoid volume and optic nerve and internal carotid artery protrusions were examined in the computed tomography scans of the paranasal sinus. Based on the protrusions, the scan findings were split into four groups: Group 1 had no protrusion, Group 2 had optic nerve protrusion, Group 3 had internal carotid artery protrusion, and Group 4 had protrusions of both the optic nerve and the internal carotid artery. Data was analysed using GraphPad Prism 9. RESULTS: Of the 300 subjects, 171(57%) were males and 129(43%) were females. The overall mean age was 39.27±10.9 years. There were 147(49%) subjects in group 4, followed by 72(24%) in group 3, 42(14%) in group 2 and 39(13%) in group 1. Statistically significant difference was observed between sphenoid volume across the study groups for both male and female subjects (p<0.001). Conclusion: There was significant relationship between internal carotid artery and optic nerve protrusions and sphenoid volume.
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Arteria Carótida Interna , Nervio Óptico , Seno Esfenoidal , Tomografía Computarizada por Rayos X , Humanos , Masculino , Femenino , Seno Esfenoidal/diagnóstico por imagen , Seno Esfenoidal/anatomía & histología , Adulto , Pakistán , Arteria Carótida Interna/anatomía & histología , Arteria Carótida Interna/diagnóstico por imagen , Estudios Transversales , Persona de Mediana Edad , Nervio Óptico/diagnóstico por imagen , Nervio Óptico/anatomía & histología , Adulto Joven , Variación AnatómicaRESUMEN
Artificial intelligence (AI) is being employed in brine mining to enhance the extraction of lithium, vital for the manufacturing of lithium-ion batteries, through improved recovery efficiencies and the reduction of energy consumption. An innovative approach was proposed combining Emotional Neural Networks (ENN) and Random Forest (RF) algorithms to elucidate the adsorption energy (AE) (kcal mol-1) of Li+ ions by utilizing crown ether (CE)-incorporated honeycomb 2D nanomaterials. The screening and feature engineering analysis of honeycomb-patterned 2D materials and individual CE were conducted through Density Functional Theory (DFT) and Gaussian 16 simulations. The selected honeycomb-patterned 2D materials encompass graphene, silicene, and hexagonal boron nitride, while the specific CEs evaluated are 15-crown-5 and 18-crown-6. The crown-passivated 2D surfaces held a significant adsorption site through van der Waals forces for efficient recovery of Li+ ions. ENN predicted the targeted adsorption sites with high precision and minimal deviation. The eTAI (XAI) based Shapley Additive exPlanations (SHAP) was also explored for insight into the feature importance of CE embedded 2D nanomaterials for the recovery of Li+ ions. The extreme gradient boosting algorithm (XGBoost) model demonstrated a RT-2-MAPE = 0.4618% and ENN-2-MAPE = 0.4839% for the feature engineering analysis. This research would be an insight into the AI-driven nanotechnology that presents a viable and sustainable approach for the extraction of natural resources through the application of brine mining.
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Significant progress has been made in designing advanced membranes; however, persistent challenges remain due to their reduced permeation rates and a propensity for substantial fouling. These factors continue to pose significant barriers to the effective utilization of membranes in the separation of oil-in-water emulsions. Metal-organic frameworks (MOFs) are considered promising materials for such applications; however, they encounter three key challenges when applied to the separation of oil from water: (a) lack of water stability; (b) difficulty in producing defect-free membranes; and (c) unresolved issue of stabilizing the MOF separating layer on the ceramic membrane (CM) support. In this study, a defect-free hydrolytically stable zirconium-based MOF separating layer was formed through a two-step method: first, by in situ growth of UiO-66-NH2 MOF into the voids of polydopamine (PDA)-functionalized CM during the solvothermal process, and then by facilitating the self-assembly of UiO-66-NH2 with PDA using a pressurized dead-end assembly. A stable MOF separating layer was attained by enriching the ceramic support with amines and hydroxyl groups using PDA, which assisted in the assembly and stabilization of UiO-66-NH2. The PDA-s-UiO-66-NH2-CM membrane displayed air superhydrophilicity and underwater superoleophobicity, demonstrating its oil resistance and high antifouling behavior. The PDA-s-UiO-66-NH2-CM membrane has shown exceptionally high permeability and separation capacity for challenging oil-in-water emulsions. This is attributed to numerous nanochannels from the membrane and its high resistance to oil adhesion. The membranes showed excellent stability over 15 continuous test cycles, which indicates that the developed MOFs separating layers have a low tendency to be clogged by oil droplets during separation. Machine learning-based Gaussian process regression (GPR) models as nonparametric kernel-based probabilistic models were employed to predict the performance efficiency of the PDA-s-UiO-66-NH2-CM membrane in oil-in-water separation. The outcomes were compared with the support vector machine (SVM) and decision tree (DT) algorithm. This efficiency includes various metrics related to its separation accuracy, and the models were developed through feature engineering to identify and utilize the most significant factors affecting the membrane's performance. The results proved the reliability of GPR optimization with the highest prediction accuracy in the validation phase. The average percentage increase of the GPR model compared to the SVM and DT model was 6.11 and 42.94%, respectively.
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Doping conventional materials with a second element is an exciting strategy for enhancing catalytic performance via electronic structure modifications. Herein, Mn-doped CdS thin films were successfully synthesized with the aid of the chemical bath deposition (CBD) by varying the pH value (8, 10, and 12) and the surfactant amount (20, 40, 60â mg). Different morphologies like nano-cubes, nanoflakes, nano-worms, and nanosheets were obtained under different deposition conditions. The optimized Mn-doped CdS synthesized at pH=8 exhibited better photoelectrochemical (PEC) performance for oxygen evolution reaction (OER) than pure CdS films, with a maximum photocurrent density of 300â µA/cm2 at an external potential of 0.5â V, under sunlight illumination. The observed performance is attributed to the successful Mn doping, porosity, high surface area, and nanosphere morphology.
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Solar-driven desalination is considered an alternative to the conventional desalination due to its nearly zero carbon footprint and ease of operating in remote areas. Water can be purified wherever sunlight is available, providing a viable solution to water shortage. Metal chalcogenide-based materials are revolutionary for solar evaporators due to their excellent photothermal conversion efficiency, facile synthesis methods, stability, and low cost. Herein we present a prototype Bi-doped CoTe nano-solar evaporator embedded on leno weave cotton gauze (Bi/CoTe@CG) using the sonication process. The nano-solar evaporator was synthesized using a simple hydrothermal approach to provide an opportunity to scale up. The as designed solar evaporator consisting of 5 % Bi/CoTe@CG showed an excellent water flux of 2.38 kg m-2 h-1 upon one sun radiation (1 kW m-2), considered among the highest literature-reported values. The introduced solar evaporator showed excellent solar efficiency of 96.7 %, good stability, and reusability for five cycles of one hour. The best doping ratio of Bi in CoTe was obtained as Bi0.5Co9.5Te with a contact angle of 11.9° in powder form. The hydrophilic nature of the designed solar-evaporator increased the water interaction with the embedded nano-solar evaporator, which helps the transfer of the heat to nearby water molecules, break their hydrogen bonding and increase the evaporation rate. The ion concentration, of the desalinated pure water collected using Bi/CoTe@CG, decreased by many orders of magnitude and it is far below the limit of WHO standards for Na+ and K+. Thus, a self-floating Bi-doped CoTe nano-solar evaporator deposited on cotton gauze (CG) is an excellent solar evaporator for seawater desalination. The proposed solar evaporator is another step towards introducing environmentally friendly desalination methods.
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Presently, there is considerable emphasis on biological synthesis of nanoparticles containing bioactive reducing compounds with an aim to mitigate the harmful effects of pollutants. The approach under study is simple and ideal for the production of durable antimicrobial nanomaterials by novel single-step green synthesis of TiO2 metal oxide nanostructures using ginger and garlic crude aqueous extracts with bactericidal and catalytic activity. A variety of experimental techniques were used to characterize the synthesized nanomaterials. As demonstrated using x-ray diffraction and ultra-violet visible spectroscopy, the produced nanoparticles exhibited high absorption at 318 nm with size varying between 23.38 nm for ginger and 58.64 nm for garlic in biologically-reduced TiO2. At increasing concentrations (500, 1000 µg/50 µl), nanoparticles reduced with garlic exhibited enhanced bactericidal efficacy against multiple drug-resistant S. aureus and effectively decomposed toxic methylene blue (MB) dye. In conclusion, biologically-reduced TiO2 nanoparticles may prove an effective tool in the fight against microbial illnesses and drug resistance.
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Mastitis Bovina , Nanopartículas del Metal , Staphylococcus aureus Resistente a Meticilina , Animales , Femenino , Bovinos , Staphylococcus aureus , Nanopartículas del Metal/química , Mastitis Bovina/tratamiento farmacológico , Antibacterianos/química , Difracción de Rayos X , Extractos Vegetales/farmacología , Extractos Vegetales/química , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
The discharge of dye effluents from the textile industries has become a major environmental issue due to its potential to impart serious harm to human health and aquatic life. Mesoporous silica due to its high chemical stability, large surface area, tunable morphologies, large pore volume and pore size and cost-effectiveness is commonly used to remove such dyes before recycling of the wastewater for agricultural, domestic, and industrial applications. However, the low colloidal stability, the fast aggregation of the silica particles and the slow etching of the silica surface often results in the fast deactivation of the adsorbents and limits their long-term applications. In this study, we report the functionalization of mesoporous silica (SBA-15) with ZnO nanoparticles for the effective removal of anionic dyes. The Zn-silica exhibited highly positive surface with a dipole moment of 172 Debye and high charge transfer efficacy with an energy bandgap (ΔE) of 3.35 eV as revealed by quantum chemical DFT simulations. It achieved excellent removal of Alizarin red dye reaching a removal efficiency of 99.99 % and an adsorption capacity of 50 mg/g. In the presence of heavy metal ions commonly present in wastewater (Cd2+, Co2+, Zn2+, Ni2+, Cu2+ and Hg2+), the Zn-silica maintain excellent stability, high selectivity, and reusability within 5 cycles without a significant decline in efficiency. This study thus presents an effective way of wastewater purification on cost-effective adsorbents for meeting the water scarcity demands.
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MXene is an incredibly promising two-dimensional material with immense potential to serve as a high-performing separating or barrier layer to develop advanced membranes. Despite the significant progress made in MXene membranes, two major challenges still exist: (i) effectively stacking MXene nanosheets into defect-free membranes and (ii) the high fouling tendency of MXene-based membranes. To address these issues, we employed sulfonated polydopamine (SPD), which simultaneously serves as a binding agent to promote the compact assembling of Ti3C2Tx MXenes (MX) nanosheets and improves the antifouling properties of the resulting sulfonated polydopamine-functionalized MX (SPDMX) membranes. The SPDMX membrane was tested for challenging surfactant-stabilized oil-in-water separation with an impressive efficiency of 98%. Moreover, an ultrahigh permeability of 1620 LMH/bar was also achieved. The sulfonation of PD helps in improving the antifouling characteristics of SPDMX by developing a strong hydration layer and enhancing the oleophobicity of the membrane. The underwater SPDMX membrane appeared superoleophobic with an oil contact angle of 153°, whereas the ceramic membrane exhibited an oil contact angle of 137°. The SPDMX membranes showed an improved flux recovery (31%) compared to the nonsulfonated counterpart. This work highlights the appropriate functionalization of MXene as a promising approach to developing MXene membranes with high permeation flux and better antifouling characteristics for oily wastewater treatment.
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Membranes are receiving significant attention to remove emerging organic micropollutants (OMPs) from wastewater and natural water sources. Herein, we report the facile preparation of a novel thin-film nanocomposite (TFN) membrane with high permeability and efficient removal of OMPs. ZnO nanoparticles were first synthesized using the co-precipitation method and functionalized with N1-(3-Trimethoxysilylpropyl)diethylenetriamine to make the surface rich with amine groups and then synthesized nanomaterials were covalently cross-linked into the active layer during the interfacial polymerization (IP) process. The performance of the membranes containing the cross-linked ZnO was significantly better than the non-cross-linked ZnO NPs containing membranes. Adding multiple hydrophilic groups and entities on the surface significantly decreased the contact angle (from â¼60° to 20°). SEM images confirmed the uniform presence and homogeneous distribution of the functionalized NPs throughout the entire membrane surface. Zeta potential measurements showed the modified membranes have a lower negative charge than the pristine membranes. Filtration studies revealed a significant increase in permeability ascribed to the creation of nanochannels in the membrane's active layer. The modified membranes outperformed commercial NF membranes in removing four common OMPs with rejection efficiencies of â¼30%, 64%, 60%, and 70% for Sulfamethoxazole, Amitriptyline, Omeprazole, and Loperamide HCl, respectively. The higher removal efficiency was attributed to the weakened hydrophobic interactions due to the presence of hydrophilic moieties and a stronger size exclusion effect. Moreover, the modified membranes showed high resistance to bacterial adhesion in static conditions.
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Polyvinylidene fluoride (PVDF) membrane-based systems for treating oily wastewater are prone to fouling. Herein, we introduced a novel mussel-inspired cationic amphiphilic terpolymer consisting of monomers N,N-diallyldimethylammonium chloride (DADMAC), N,N-diallyltetradecan-1-ammonium chloride (DTDAC), and mussel-inspired N,N-diallyldopamine hydrochloride (DADAHC) to improve the performance and characteristics of the PVDF membranes for oil-in-water emulsion separations. The cationic terpolymer, poly(DADMAC-co-DTDAC-co-DADAHC), shortened as PDDD, was synthesized in excellent yields via free radical polymerization and has good compatibility with the PVDF owing to the presence of hydrophobic long alkyl chains in DTDAC. The presence of dopamine motifs helps stabilize the PDDD-PVDF membrane by chelating with Fe3+ ions. The water contact angle on the PDDD-incorporated PVDF membranes was reduced from 87.6 to 54.6°, demonstrating improved hydrophilicity than pristine PVDF (M-0). The incorporation of PDDD into the PVDF improved the separation efficiencies of the membrane, which reached up to 99% while treating the oil-in-water emulsions. Incorporating PDDD into PVDF has significantly enhanced the anti-fouling characteristics of the membranes, which are indicated by their remarkable flux recovery ratio (FRR) (up to 92%). The hydrophobic and hydrophilic groups worked synergetically to enhance the performance of the fabricated membrane.
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In this research study, waste fly ash (WFA) underwent acid activation and subsequent amine functionalization using ammonia solution. This treatment improves the porosity, thermal tendency and crystallinity of WFA. Modified WFA was tested under different experimental conditions to treat the wastewater consisting of different concentrations of cationic (methylene blue and rhodamine 6G) and anionic (methyl orange) dyes. As an individual, methylene blue (MB) and rhodamine 6G (Rh) showed ~ 100% and ~ 82% removal efficiencies respectively in an alkaline medium while methyl orange (MO) exhibited only ~ 20% adsorption in the same medium. An antagonistic effect was observed in adsorption when wastewater contains both cationic dyes whereas the combination of cationic and anionic dyes in solution manifested a synergistic effect. For all individual and binary dye combinations, there is a close agreement in observed and calculated uptakes when the data was fitted to the fractional order kinetic rate equation. The adsorption of all dyes is spontaneous and endothermic in nature except for MB/MO combination where the process is exothermic in nature. 24.93 mg/g, 24.83 mg/g, and 14.95 mg/g monolayer uptake capacities of MB, Rh, and MO were found respectively from isothermal analysis of single dye adsorption data. Further, extended sips model gave higher correlation coefficient (R2 = 0.99) and addressed the failed assumptions of both the Langmuir and Freundlich models. Overall, in the experimental results, the modified waste fly ash could act as successful adsorbent to treat dye bearing wastewater.
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Aguas Residuales , Contaminantes Químicos del Agua , Colorantes , Ceniza del Carbón , Azul de Metileno , Cinética , Adsorción , CationesRESUMEN
The separation of oil/water emulsions has attracted considerable attention for decades due to the negative environmental impacts brought by wastewater. Among the various membranes investigated for separation, polyvinylidene fluoride (PVDF) membranes have shown significant advantages of ease of fabrication, high selectivity, and fair pore distribution. However, PVDF membranes are hydrophobic and suffer from severe fouling resulting in substantial flux decline. Meanwhile, the incorporation of wettable substrates during fabrication has significantly impacted the membrane performance by lowering the fouling propensity. Herein, we report the fabrication of an iron-containing porphyrin (hemin)-modified multi-walled carbon nanotube incorporated PVDF membrane (HA-MWCNT) to enhance fouling resistance and the effective separation of oil-in-water emulsions. The fabricated membrane was thoroughly investigated using the FTIR, SEM, EDX, AFM, and contact angle (CA) analysis. The HA-MWCNT membrane exhibited a water CA of 62° ± 0.5 and excellent pure water permeance of 300.5 L/m2h at 3.0 bar (400% increment), in contrast to the pristine PVDF, which recorded a CA of 82° ± 0.8 and water permeance of 59.9 L/m2h. The hydrophilic HA-MWCNT membrane further showed an excellent oil rejection of >99% in the transmembrane pressure range of 0.5−2.5 bar and a superb flux recovery ratio (FRR) of 82%. Meanwhile, the classical molecular dynamics (MD) simulations revealed that the HA-MWCNT membrane had greater solvent-accessible pores, which enhanced water permeance while blocking the hydrocarbons. The incorporation of the hemin-modified MWCNT is thus an excellent strategy and could be adopted in the design of advanced membranes for oil/water separation.
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Nanotubos de Carbono , Purificación del Agua , Emulsiones , Hemina , Membranas Artificiales , Purificación del Agua/métodosRESUMEN
The oil/water separation has received significant attention due to its critical environmental impact. The special wettable surfaces are highly desired to deal with the oil/water mixtures. This work demonstrates a simple two-step method to develop a superhydrophobic Azadirachta indica leaves like Ag-decorated electrochemically copper-coated stainless-steel mesh (SH-AIL-Ag-EC-Cu-Mesh) for efficient separation of oil/water mixtures. In the first step, the electrodeposition of the copper took place on the mesh surface at a suitable applied potential. In the second step, the galvanic replacement reaction between the Ag+ and electrodeposited Cu produced the fascinating superhydrophobic Ag leaves on the mesh surface. The SH-AIL-Ag-EC-Cu-Mesh was thoroughly characterized by the X-ray photoelectron spectroscopy (XPS), Energy Dispersive X-Ray Spectroscopy (EDX), elemental mapping, surface wettability analysis, and the contact analyzer. The morphological analysis has shown the unique leafy structures of the reduced Ag on the surface of the mesh. The XPS analysis has confirmed that most of the Ag present on the surface is in zerovalent form. The combination of the electrodeposition and the displacement reaction between the copper and the silver turned the surface superhydrophobic, and the water contact angle was significantly improved from 115° to 158°. The designed SH-AIL-Ag-EC-Cu-Mesh has shown excellent selectivity for oil in oil/water mixtures with a separation efficiency of 99.1% with an exceptionally high flux of 8963 L m-2h-1. The SH-AIL-Ag-EC-Cu-Mesh has shown excellent reusability, and after 15 cycles of separation, no significant decrease in the oil/water separation efficiency was observed.
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Azadirachta , Cobre , Humectabilidad , Galvanoplastia , Espectroscopía de FotoelectronesRESUMEN
Chiral Metal-Organic Frameworks (CMOFs) are unique crystalline and porous class of materials which is composed of organic linkers and metal ions. CMOFs surpass traditional organic and inorganic porous materials because of their tunable shape, size, functional diversity, and selectivity. Specific applications of CMOFs may be exploited by introducing desired functional groups. CMOFs have chiral recognition abilities, making them unique for chiral compound synthesis and separation. The CMOFs can be synthesized through different approaches. Two main approaches have been discussed, i.e., direct and indirect synthesis. Synthetic strategies play an essential role in getting desired properties in MOFs. CMOFs find potential applications in adsorption, asymmetric catalysis, luminescence, degradation, and enantioselective separation. The MOFs' porosity, stability, and reusability make them an attractive material for these applications. The plethora of applications of CMOFs have motivated chemists to synthesize novel MOFs and number of MOFs have been ever-escalating. Herein, the synthetic methods of CMOFs and their various applications have been discussed.
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The separation of the emulsified oil/water is one of the critical environmental challenges. The PVDF membranes have been found helpful for separation, but rapid fouling makes them less attractive in treating oil-in-water emulsions. The design of antifouling membranes has become an area of deep interest. Herein, developing a novel modified PVDF ultrafiltration membrane was reported by doping the pyrrole and solidifying it in a ferric-containing coagulation bath, resulting in a unique nanotextured PVDF membrane (CCB-Fe/PPnp-PVDF) to separate the oil/water emulsions. The resultant CCB-Fe/PPnp-PVDF membrane was thoroughly characterized using the FTIR, FE-SEM, EDX, mapping, AFM, and contact analyzer. The hydrophilicity of the CCB-Fe/PPnp-PVDF was substantially improved, and the water contact angle was reduced from 81Ö¯ ± 0.9Ö¯ to 44Ö¯ ± 1.7Ö¯. The CCB-Fe/PPnp-PVDF membrane flux increased by 121% compared to the pristine PVDF membrane, with high separation efficiency of 99%. The hydrophilic nanotextured surface of the CCB-Fe/PPnp-PVDF membrane showed good antifouling behavior, with a flux recovery ratio (FRR) of more than 96%. Irreversible flux was just less than 4%. The high flux recovery ratio indicated that the nanotextured surface produced by the Fe/PPnp had prevented the blockage of the membrane pores and compact cake layer formation, which makes it an excellent membrane for oil/water emulsion separation. This strategy can be adopted for designing advanced membranes for separation applications.
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Membranas Artificiales , Purificación del Agua , Emulsiones , Polímeros de Fluorocarbono , Polivinilos , Pirroles , Purificación del Agua/métodosRESUMEN
An ultra-sensitive sensor of dopamine is introduced. The sensor is constructed by encapsulating platinum nanoparticles (PtNPs) between reduced graphene oxide (GR) nanosheets. The sandwiched PtNPs between GR layers acted as a spacer to prevent aggregation and provided a fine connection between the GR nanosheets to provide fast charge transfer. This specific orientation of the GR nanosheets and PtNPs on the graphite pencil electrode (GPE) substantially improved the electrocatalytic activity of the sensor. The synthesized graphene oxide and the fabricated sensor were comprehensively characterized by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, field emission-scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and square wave voltammetry (SWV). The value of the charge transfer coefficient (α), apparent heterogeneous electron transfer rate constant (k s), and electroactive surface area for dopamine were found to be about 0.57, 8.99 s-1, and 0.81 cm2, respectively. The developed sensor is highly sensitive towards dopamine, and the detection limit is 9.0 nM. The sensor response is linear for dopamine concentration from 0.06 to 20 µM (R 2 = 0.9991). The behavior of the sensor for dopamine in the presence of a high concentration of l(+) Ascorbic acid and other potential interferents was satisfactory. High recovery percentage between 90% and 105% in the human urine sample, good reproducibility, and facile fabrication of the electrode make it a good candidate for dopamine sensing.
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The release of mercury into the environment has adverse effects on humans and aquatic species, even at very low concentrations. Pyrene and its derivatives have interesting fluorescence properties that can be utilized for mercury (Hg2+) ion sensing. Herein, we reported the highly selective pyrene-functionalized silica nanoparticles (Pyr-NH@SiO2 NPs) for chemosensing mercury (Hg2+) ions in a seawater sample. The Pyr-NH@SiO2 NPs were synthesized via a two-step protocol. First, a modified Stöber method was adopted to generate amino-functionalized silica nanoparticles (NH2@SiO2 NPs). Second, 1-pyrenecarboxylic acid was coupled to NH2@SiO2 NPs using a peptide coupling reaction. As-synthesized NH2@SiO2 NPs and Pyr-NH@SiO2 NPs were thoroughly investigated by 1H-NMR, FTIR, XRD, FESEM, EDS, TGA, and BET surface area analysis. The fluorescent properties were examined in deionized water under UV-light illumination. Finally, the developed Pyr-NH@SiO2 NPs were tested as a chemosensor for Hg2+ ions detection in a broad concentration range (0-50 ppm) via photoluminescence (PL) spectroscopy. The chemosensor can selectively detect Hg2+ ions in the presence of ubiquitous ions (Na+, K+, Ca2+, Mg2+, Ba2+, Ag+, and seawater samples). The quenching of fluorescence properties with Hg2+ ions (LOD: 10 ppb) indicates that Pyr-NH@SiO2 NPs can be effectively utilized as a promising chemosensor for mercury ion detection in seawater environments.