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1.
Environ Res ; 220: 115160, 2023 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-36580987

RESUMEN

Humic acid (HA) is a complex organic compound made up of small molecules. A variety of raw materials are used to manufacture HA, due to which the structure and composition of HA vary widely. In this study, nitric acid oxidation of two coal samples from Lakhra (Pakistan) was followed by HA extraction using 2.5, 3.0 and 3.5% KOH solutions. The impact of different operating parameters such as; the effect of KOH concentrations, KOH-coal proportion, extraction time and pH range influencing the HA extraction efficiency was optimally investigated. Commercial HA applications possess numerous challenges, including valuable applications and sub-optimal extraction techniques. A significant limitation of conventional experimental methods is that they can only investigate one component at a time. It is necessary to improve the current processing conditions, this can only be achieved by modelling and optimization of the process conditions to meet market demands. A comprehensive evaluation and prediction of HA extraction using Response Surface Methodology (RSM) are also being reported for the first time in this study. The maximum HA extraction efficiency of 89.32% and 87.04% for coal samples 1 and 2 respectively was achieved with the lowest possible pH of 1.09 (coal sample 1) and 1(coal sample 2), which is remarkably lower as compared to those reported in the literature for conventional alkaline extraction process. The model was evaluated for two coal samples through the coefficient of determination (R2), Root Means Square Error (RMSE), and Mean Average Error (MEE). The results of RSM for coal sample 1 (R2 = 0.9795, RMSE = 4.784) and coal sample 2 (R2 = 0.9758, RMSE = 4.907) showed that the model is well suited for HA extraction efficiency predictions. The derived humic acid from lignite coal was analyzed using elemental analysis, UV-Visible spectrophotometry and Fourier-transformed infrared (FTIR) spectroscopy techniques. Scanning Electron Microscopy (SEM) was applied to analyze the morphological modifications of the extracted HA after treatment with 3.5% KOH solution. For agricultural objectives, such as soil enrichment, enhancing plant growth conditions, and creating green energy solutions, this acquired HA can be made bioactive. This study not only establishes a basis for research into the optimized extraction of HA from lignite coal, but it also creates a new avenue for the efficient and clean use of lignite.


Asunto(s)
Carbón Mineral , Sustancias Húmicas , Sustancias Húmicas/análisis , Suelo , Compuestos Orgánicos , Espectroscopía Infrarroja por Transformada de Fourier
2.
Environ Monit Assess ; 195(10): 1142, 2023 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-37665398

RESUMEN

Graphitic carbon nitride (g-CN) has a number of valuable features that have been recognized during the studies related to its photocatalytic activity enhancement derived by visible light. Because of these characteristics, g-CN can be used as a detecting signal transducer with different transmission modalities. The latest up-to-date detection capabilities of modified g-CN nanoarchitectures are covered in this study. The structural features and synthetic methodologies have been discussed in a number of reports. Herein, employment of the g-CN as a promising probing modality for the recognition of different toxic heavy metals is the promising feature of the present study.


Asunto(s)
Contaminantes Ambientales , Metales Pesados , Monitoreo del Ambiente , Agua
3.
Chem Rec ; 22(8): e202200062, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35641392

RESUMEN

Covalent organic frameworks (COFs) are a promising class of porous crystalline materials made up of covalently connected and periodically protracted network topologies through organic linkers. The tailorability of organic linker and intrinsic structures endow COFs with a tunable porosity and structure, low density, facilely-tailored functionality, and large surface area, attracting increasing amount of interests in variety of research areas of membrane separations. COF-based membranes have spawned a slew of new research projects, ranging from fabrication methodologies to separation applications. Herein, we tried to emphasis the major developments in the synthetic approaches of COFs based membranes for a variety of separation applications such as, separation of gaseous mixtures, water treatment as well as separation of isomeric and chiral organic compounds. The proposed methods for fabricating COF-based continuous membranes and columns for real world applications are also thoroughly explored. Finally, a viewpoint on the future directions and remaining challenges for COF research in the area of separation is provided.


Asunto(s)
Estructuras Metalorgánicas , Purificación del Agua , Gases , Estructuras Metalorgánicas/química , Compuestos Orgánicos , Porosidad
4.
Crit Rev Food Sci Nutr ; 62(14): 3913-3929, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-33427482

RESUMEN

Naturally occurring plant-based gums and their engineered bio-nanostructures have gained an immense essence of excellence in several industrial, biotechnological, and biomedical sectors of the modern world. Gums derived from bio-renewable resources that follow green chemistry principles are considered green macromolecules with unique structural and functional attributes. For instance, gum mostly obtained as exudates are bio-renewable, bio-degradable, bio-compatible, sustainable, overall cost-effective, and nontoxic. Gum exudates also offer tunable attributes that play a crucial role in engineering bio-nanostructures of interest for several bio- and non-bio applications, e.g., food-related items, therapeutic molecules, sustained and controlled delivery cues, bio-sensing constructs, and so on. With particular reference to plant gum exudates, this review focuses on applied perspectives of various gums, i.e., gum Arabic, gum albizzia, gum karaya, gum tragacanth, and gum kondagogu. After a brief introduction with problem statement and opportunities, structural and physicochemical attributes of plant-based natural gums are presented. Following that, considerable stress is given to green synthesis and stabilization of gum-based bio-nanostructures. The final part of the review focuses on the bio- and non-bio related applications of various types of gums polysaccharides-oriented bio-nanostructures.


Asunto(s)
Nanoestructuras , Tragacanto , Goma Arábiga/química , Gomas de Plantas , Polisacáridos , Tragacanto/química
5.
Environ Res ; 204(Pt D): 112387, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34785206

RESUMEN

Wastewater treatment and electricity generation have been the major concerns for the last few years. The scarcity of fossil fuels has led to the development of unconventional energy resources that are pollution-free. Microbial fuel cell (MFC) is an environmental and eco-friendly technology that harvests energy through the oxidation of organic substrates and transform into the electric current with the aid of microorganisms as catalysts. This review presents power output and colour removal values by designing various configurations of MFCs and highlights the importance of materials for the fabrication of anode and cathode electrodes playing vital roles in the formation of biofilm and redox reactions taking place in both chambers. The electron transfer mechanism from microbes towards the electrode surface and the generation of electric current are also highlighted. The effect of various parameters affecting the cell performance such as type and amount of substrate, pH and temperature maintained within the chambers have also been discussed. Although this technology presents many advantages, it still needs to be used in combination with other processes to enhance power output.


Asunto(s)
Fuentes de Energía Bioeléctrica , Purificación del Agua , Electricidad , Electrodos , Tecnología , Aguas Residuales
6.
Environ Res ; 214(Pt 2): 113790, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35809637

RESUMEN

A novel adsorbent was prepared by blending chitosan (CS) and acrylic acid (AA) while using formaldehyde as a cross linker in the form of hydrogel beads. The adsorption properties of these hydrogel beads for the removal of toxic metal ions (Pb2+ and Cd2+) from aqueous solutions were evaluated. The hydrogel beads have a 3D macro-porous structure whose -NH2 groups were considered to be the dominant binding specie for Cd and Pb ions. The equilibrium adsorption capacity (qe) of beads was significantly affected by the mass ratio of sorbent and sorbate. The percentage removal of Cd and Pb ions was observed to be enhanced with the increase in sorbate concentration. The hydrogel beads maintained good adsorption properties at adsorption-desorption equilibrium. The Langmuir and Freundlich models were used to elaborate the isotherms as well as isotherm constants. Adsorption isothermal data is well explained by the Freundlich model. The data of experimental kinetics is interrelated with the second-order kinetic model, which showed that the chemical sorption phenomenon is the rate limiting step. The results of intraparticle diffusion model described the adsorption process occurred on a porous substance that proved chitosan/Formaldehyde beads to be the favorable adsorbent.


Asunto(s)
Quitosano , Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Cadmio , Quitosano/química , Formaldehído , Hidrogeles/química , Concentración de Iones de Hidrógeno , Iones , Cinética , Plomo , Porosidad , Agua/química , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos
7.
Mikrochim Acta ; 189(11): 426, 2022 10 19.
Artículo en Inglés | MEDLINE | ID: mdl-36260130

RESUMEN

Monitoring of pollutant and toxic substances is essential for cleaner environment and healthy life. Sensing of various environmental contaminants and biomolecules such as heavy metals, pharmaceutics, toxic gases, volatile organic compounds, food toxins, and pathogens is of high importance to guaranty the good health and sustainable environment to community. In recent years, graphitic carbon nitride (g-CN) has drawn a significant amount of interest as a sensor due to its large surface area and unique electrochemical properties, low bandgap energy, high thermal and chemical stability, facile synthesis, nontoxicity, and electron rich property. Furthermore, the binary and ternary nanocomposites of graphitic carbon nitride further enhance their performance as a sensor making it a cost effective, fast, and reliable gadget for the purpose, and opens a wide area of research. Numerous reviews addressing a variety of applications including photocatalytic energy conversion, photoelectrochemical detection, and hydrogen evolution of graphitic carbon nitride have been documented to date. But a lesser attention has been devoted to the mechanistic approaches towards sensing of variety of pollutants concerned with environmental and biological aspects. Herein, we present the sensing features of graphitic carbon nitride towards the detection of various analytes including toxic heavy metals, pharmaceuticals, phenolic compounds, nitroaromatic compounds, volatile organic molecules, toxic gases, and foodborne pathogens. This review will undoubtedly provide future insights for researchers working in the field of sensors, allowing them to investigate the intriguing graphitic carbon nitride material as a sensing platform that is comparable to several other nanomaterials documented in the literature. Therefore, we hope that this study could reveal some intriguing sensing properties of graphitic carbon nitride, which may help researchers better understand how it interacts with contaminants of environmental and biological concern. Graphitic carbon nitride Nanosheets as Promising Analytical Tool for Environmental and Biological Monitoring of Hazardous Substances.


Asunto(s)
Contaminantes Ambientales , Nanocompuestos , Compuestos Orgánicos Volátiles , Nanocompuestos/química , Gases , Sustancias Peligrosas , Hidrógeno , Preparaciones Farmacéuticas
8.
Int J Mol Sci ; 22(14)2021 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-34299082

RESUMEN

The Mimosa genus belongs to the Fabaceae family of legumes and consists of about 400 species distributed all over the world. The growth forms of plants belonging to the Mimosa genus range from herbs to trees. Several species of this genus play important roles in folk medicine. In this review, we aimed to present the current knowledge of the ethnogeographical distribution, ethnotraditional uses, nutritional values, pharmaceutical potential, and toxicity of the genus Mimosa to facilitate the exploitation of its therapeutic potential for the treatment of human ailments. The present paper consists of a systematic overview of the scientific literature relating to the genus Mimosa published between 1931 and 2020, which was achieved by consulting various databases (Science Direct, Francis and Taylor, Scopus, Google Scholar, PubMed, SciELO, Web of Science, SciFinder, Wiley, Springer, Google, The Plant Database). More than 160 research articles were included in this review regarding the Mimosa genus. Mimosa species are nutritionally very important and several species are used as feed for different varieties of chickens. Studies regarding their biological potential have shown that species of the Mimosa genus have promising pharmacological properties, including antimicrobial, antioxidant, anticancer, antidiabetic, wound-healing, hypolipidemic, anti-inflammatory, hepatoprotective, antinociceptive, antiepileptic, neuropharmacological, toxicological, antiallergic, antihyperurisemic, larvicidal, antiparasitic, molluscicidal, antimutagenic, genotoxic, teratogenic, antispasmolytic, antiviral, and antivenom activities. The findings regarding the genus Mimosa suggest that this genus could be the future of the medicinal industry for the treatment of various diseases, although in the future more research should be carried out to explore its ethnopharmacological, toxicological, and nutritional attributes.


Asunto(s)
Etnofarmacología , Mimosa/química , Fitoquímicos/farmacología , Fitoterapia/métodos , Extractos Vegetales/farmacología , Humanos
9.
J Environ Manage ; 287: 112257, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33690013

RESUMEN

The economic developments around the globe resulted in the increased demand of energy, which overburdened the supply chain sources of energy. Fossil fuel reserves are exploited to meet the high demand of energy and their combustion is becoming the main source of environmental pollution. So there is dire need to find safe, renewable and sustainable energy resources. Waste to energy (WtE) may be viewed as a possible alternate source of energy, which is economically and environmentally sustainable. Municipal solid waste (MSW) is a major contributor to the development of renewable energy and sustainable environment. At present the scarcity of renewable energy resources and disposal of MSW is a challenging problem for the developing countries, which has generated a wide ranging socioeconomic and environmental problems. This situation stimulates the researchers to develop alternatives for converting WtE under a variety of scenarios. Herein, the present scenario in developing the WtE technologies such as, thermal conversion methods (Incineration, Gasification, Pyrolysis, Torrefaction), Plasma technology, Biochemical methods, Chemical and Mechanical methods, Bio-electrochemical process, Mechanical biological treatment (MBT), Photo-biological processes for efficacious energy recovery and the challenges confronted by developing and developed countries. In this review, a framework for the evaluation of WtE technologies has been presented for the ease of researchers working in the field. Furthermore, this review concluded that WtE is a potential renewable energy source that will partially satisfy the demand for energy and ensure an efficient MSW management to overcome the environmental pollution.


Asunto(s)
Eliminación de Residuos , Administración de Residuos , Biomasa , Incineración , Residuos Sólidos , Tecnología
10.
Environ Res ; 185: 109436, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32278154

RESUMEN

An alarming number of contaminants of emerging concern, including active residues from pharmaceuticals and personal care products (PPCPs), are increasingly being introduced in water systems and environmental matrices due to unavoidable outcomes of modern-day lifestyle. Most of the PPCPs based contaminants are not completely eliminated during the currently used water/wastewater treatment processes. Therefore, highly selective and significant removal of PPCPs from environmental matrices remains a scientific challenge. In recent years, a wide range of metal-organic frameworks (MOFs) and MOF-based nanocomposites have been designed and envisioned for environmental remediation applications. MOF-derived novel cues had shown an adsorptive capability for the extraction and removal of an array of trace constituents in environmental samples. Noteworthy features such as substantial surface area, size, dispersibility, tunable structure, and repeated use capability provide MOFs-derived platform a superiority over in-practice conventional adsorptive materials. This review provides a comprehensive evaluation of the efficient removal or mitigation of various categories of PPCPs by diverse types of MOF-derived adsorbents with suitable examples. The growing research investigations in this direction paves the way for designing more efficient porous nanomaterials that would be useful for the elimination of PPCPs, and separation perspectives.


Asunto(s)
Estructuras Metalorgánicas , Preparaciones Farmacéuticas , Purificación del Agua , Adsorción , Aguas Residuales
11.
Molecules ; 25(7)2020 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-32244456

RESUMEN

Metal-organic frameworks (MOFs) are a fascinating class of porous crystalline materials constructed by organic ligands and inorganic connectors. Owing to their noteworthy catalytic chemistry, and matching or compatible coordination with numerous materials, MOFs offer potential applications in diverse fields such as catalysis, proton conduction, gas storage, drug delivery, sensing, separation and other related biotechnological and biomedical applications. Moreover, their designable structural topologies, high surface area, ultrahigh porosity, and tunable functionalities all make them excellent materials of interests for nanoscale applications. Herein, an effort has been to summarize the current advancement of MOF-based materials (i.e., pristine MOFs, MOF derivatives, or MOF composites) for electrocatalysis, photocatalysis, and biocatalysis. In the first part, we discussed the electrocatalytic behavior of various MOFs, such as oxidation and reduction candidates for different types of chemical reactions. The second section emphasizes on the photocatalytic performance of various MOFs as potential candidates for light-driven reactions, including photocatalytic degradation of various contaminants, CO2 reduction, and water splitting. Applications of MOFs-based porous materials in the biomedical sector, such as drug delivery, sensing and biosensing, antibacterial agents, and biomimetic systems for various biological species is discussed in the third part. Finally, the concluding points, challenges, and future prospects regarding MOFs or MOF-based materials for catalytic applications are also highlighted.


Asunto(s)
Estructuras Metalorgánicas/química , Bioingeniería , Catálisis , Señales (Psicología) , Oxidación-Reducción , Procesos Fotoquímicos , Porosidad , Relación Estructura-Actividad
12.
J Environ Manage ; 234: 253-264, 2019 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-30634118

RESUMEN

In recent years, owing to the serious ecological risks and human health-related adverse effects, the wide occurrence of hazardous contaminants along with their potential to enter the environment have gained great public concerns. In this context, significant actions are urgently required to tackle the ignorance and inefficient monitoring/removal of emerging/(re)-emerging contaminants (ECs) in the environment from different routes of concerns, i.e., industrial waste, pharmaceutical, personal care products (PCPs), toxic effluents, etc. Laccases are multinuclear copper-containing oxidoreductases and can carry out one electron oxidation of a broad spectrum of environmentally related contaminants. In biotechnology, this group of versatile enzymes is known as a green catalyst/green tool with enormous potentialities to tackle ECs of high concern. In this review, we endeavored to present up-to-date literature concerning the potential use of immobilized laccases for the degradation and remediation of various types of environmental pollutants present in the environment. Both, pristine and immobilized, laccases have shown great capacity to oxidative degradation and mineralization of endocrine disrupting chemicals (EDs) in batch treatment processes as well as in large-scale continuous reactors. These properties make laccase as particularly attractive biocatalysts in environmental remediation processes, and their use might be advantageous over the conventional treatments. This review summarizes the most significant recent advances in the use of laccases and their future perspectives in environmental biotechnology.


Asunto(s)
Disruptores Endocrinos , Contaminantes Ambientales , Biotecnología , Humanos , Residuos Industriales , Lacasa
13.
Molecules ; 24(6)2019 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-30901827

RESUMEN

In this study, we reviewed state-of-the-art endogenous-based and exogenous-based stimuli-responsive drug delivery systems (DDS) for programmed site-specific release to overcome the drawbacks of conventional therapeutic modalities. This particular work focuses on the smart chemistry and mechanism of action aspects of several types of stimuli-responsive polymeric carriers that play a crucial role in extracellular and intracellular sections of diseased tissues or cells. With ever increasing scientific knowledge and awareness, research is underway around the globe to design new types of stimuli (external/internal) responsive polymeric carriers for biotechnological applications at large and biomedical and/or pharmaceutical applications, in particular. Both external/internal and even dual/multi-responsive behavior of polymeric carriers is considered an essential element of engineering so-called 'smart' DDS, which controls the effective and efficient dose loading, sustained release, individual variability, and targeted permeability in a sophisticated manner. So far, an array of DDS has been proposed, developed, and implemented. For instance, redox, pH, temperature, photo/light, magnetic, ultrasound, and electrical responsive DDS and/or all in all dual/dual/multi-responsive DDS (combination or two or more from any of the above). Despite the massive advancement in DDS arena, there are still many challenging concerns that remain to be addressed to cover the research gap. In this context, herein, an effort has been made to highlight those concerning issues to cover up the literature gap. Thus, the emphasis was given to the drug release mechanism and applications of endogenous and exogenous based stimuli-responsive DDS in the clinical settings.


Asunto(s)
Portadores de Fármacos , Sistemas de Liberación de Medicamentos , Liberación de Fármacos , Animales , Humanos , Concentración de Iones de Hidrógeno , Luz , Nanopartículas , Nanotecnología , Especificidad de Órganos , Oxidación-Reducción , Estimulación Física , Polímeros , Temperatura
14.
Langmuir ; 34(9): 3058-3067, 2018 03 06.
Artículo en Inglés | MEDLINE | ID: mdl-29429347

RESUMEN

A novel thermoresponsive hyperbranched multiarm copolymer with a hydrophobic hyperbranched poly[3-ethyl-3-(hydroxymethyl)oxetane] core and many poly(acrylamide- co-acrylonitrile) (P(AAm- co-AN)) arms was for the first time synthesized through a reversible addition-fragmentation chain-transfer polymerization. These copolymers show reversible, sharp, and controlled temperature-responsive phase transitions at the upper critical solution temperature (UCST) in water and electrolyte solution. It is the first report on the hyperbranched copolymers with a UCST transition. Two series copolymers with variable AN content (series A) and variable arm length (series B) were synthesized to study the influence of molecular structure on the UCST transition. It was found that the UCST of copolymers could be raised by increasing the AN content or decreasing the arm length. Most interestingly, the amplification effect of the hyperbranched topological structure leads to a broad change of the UCST from 33.2 to 65.2 °C with the little change of AN content (5.9%). On the basis of variable temperature nuclear magnetic resonance, dynamic light scattering, and transmission electron microscopy, a UCST transition mechanism, in combination with hydrophilic/hydrophobic balance and multimicelle aggregate (MMA), was proposed. This work enriches the UCST copolymer topology and may extend the knowledge on the structure-activity relationship as well as the mechanism of the UCST polymers.

15.
Mar Drugs ; 16(2)2018 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-29463058

RESUMEN

In recent decades, environmental pollution has emerged as a core issue, around the globe, rendering it of fundamental concern to eco-toxicologists, environmental biologists, eco-chemists, pathologists, and researchers from other fields. The dissolution of polluting agents is a leading cause of environmental pollution of all key spheres including the hydrosphere, lithosphere, and biosphere, among others. The widespread occurrence of various pollutants including toxic heavy metals and other emerging hazardous contaminants is a serious concern. With increasing scientific knowledge, socioeconomic awareness, human health problems, and ecological apprehensions, people are more concerned about adverse health outcomes. Against this background, several removal methods have been proposed and implemented with the aim of addressing environmental pollution and sustainable and eco-friendly development. Among them, the biosorption of pollutants using naturally inspired sources, e.g., marine algae, has considerable advantages. In the past few years, marine algae have been extensively studied due to their natural origin, overall cost-effective ratio, and effectiveness against a broader pollutant range; thus, they are considered a potential alternative to the conventional methods used for environmental decontamination. Herein, an effort has been made to highlight the importance of marine algae as naturally inspired biosorbents and their role in biosorption. Biosorption mechanisms and factors affecting biosorption activities are also discussed in this review. The utilization of marine algae as a biosorbent for the removal of numerous potentially toxic elements has also been reviewed.


Asunto(s)
Biodegradación Ambiental/efectos de los fármacos , Contaminantes Ambientales/química , Contaminación Ambiental/prevención & control , Phaeophyceae/química , Adsorción/fisiología , Animales , Humanos
16.
Environ Manage ; 61(1): 171-180, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29071551

RESUMEN

In this study, the toxicological and degradation profile of Reactive Black 5 (RB5) dye was evaluated using a UV/TiO2-based degradation system. Fourier transform infrared spectroscopy (FT-IR), thin layer chromatography (TLC), high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) techniques were used to evaluate the degradation level of RB5. The UV-Vis spectral analysis revealed the disappearance of peak intensity at 599 nm (λmax). The FT-IR spectrum of UV/TiO2 treated dye sample manifest appearance of new peaks mainly because of the degraded product and/or disappearance of some characteristics peaks which were present in the untreated spectrum. The HPLC profile verified the RB5 degradation subject to the formation of metabolites at different retention times. A stable color removal higher than 96% with COD removal in the range of 74-82.3% was noted at all evaluated dye concentrations. The tentative degradation pathway of RB5 is proposed following a careful analysis of the intermediates identified by UPLC-MS. Toxicity profile of untreated and degraded dye samples was monitored using three types of human cell lines via MTT assay and acute toxicity testing with Artemia salina. In conclusion, the UV/TiO2-based degradation system could be effectively employed for the remediation of textile wastewater comprising a high concentration of reactive dyes.


Asunto(s)
Colorantes/química , Naftalenosulfonatos/química , Titanio/química , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Cromatografía Liquida , Colorantes/toxicidad , Humanos , Naftalenosulfonatos/toxicidad , Espectroscopía Infrarroja por Transformada de Fourier , Rayos Ultravioleta , Aguas Residuales/análisis , Contaminantes Químicos del Agua/toxicidad , Purificación del Agua/instrumentación
17.
J Nanosci Nanotechnol ; 14(10): 7427-31, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25942804

RESUMEN

Human hand signifies a magnificent and challenging example for scientists and engineers trying to replicate its complex structure and functionality. This paper proposes a bio-mechatronic approach for the design of an anthropomorphic artificial hand capable of performing basic human hand motions with fundamental gripping functionality. The dexterity of the artificial hand is exhibited by imitating the natural motion of the human fingers. Imitation is produced according to the data acquired from the flex sensors attached to the human fingers. In order to have proper gripping, closed-loop control is implemented using the tactile sensors. Feedback for the closed-loop control is provided by force sensing resistors (FSRs), attached on the fingertips of the robotic hand. These sensors also enable handling of fragile objects. The mathematical model is derived using forward kinematics and also simulated on MATLAB to ascertain the position of robotic fingers in 3D space.


Asunto(s)
Mano , Robótica/economía , Robótica/instrumentación , Simulación por Computador , Diseño de Equipo/economía , Dedos/fisiología , Mano/fisiología , Fuerza de la Mano , Humanos
18.
Adv Colloid Interface Sci ; 329: 103186, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38763047

RESUMEN

The interaction between two surfaces leads to the generation of friction and wear of material. Friction and wear are some of the major challenges that may readily be overcome by the third part of tribology called lubrication. Utilizing solid lubricants including polymers, carbon-based materials, soft metals, transition metal dichalcogenides, along with their potential benefits and drawbacks in dry environments can reduce friction. Recently, an emerging class of two-dimensional (2D) transition metal nitrides, carbides or carbonitrides commonly known as MXenes have emerged as an attractive alternative for solid lubrication because of their ability to establish wear-resistant tribo layers and well as low friction and shear strength. Furthermore, the inherent hydrophilic nature of these substances has led to limited dispersion stability and phase compatibility when combined with pure base oils. As a result, their potential use as solid lubricants and lubricant additives has been impeded. To address this issue and enhance the applicability of MXenes as solid lubricants, their surface modification can be an attractive tool. Therefore, this review provides a succinct summary of the current state-of-the-art in surface functionalization of MXenes, a subject that has not yet been thoroughly addressed. Further, the mechanical behavior of MXenes and composites has been discussed, followed by the potential of MXenes as a solid lubricant at micro- and macro-scale. Finally, the existing opportunities and challenges of the research area have been discussed with possible future research directions. We believe, this article will be a valuable resource for MXenes and opens the door to improve the chemical, physical and mechanical properties of MXenes in various applications, such as solid lubrication.

19.
Chemosphere ; 357: 141955, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38614403

RESUMEN

A novel family of multifunctional nanomaterials called MXenes is quickly evolving, and it has potential applications that are comparable to those of graphene. This article provides a current explanation of the design and performance assessment of MXene-based membranes. The production of MXenes nanosheets are first described, with an emphasis on exfoliation, dispersion stability, and processability, which are essential elements for membrane construction. Further, critical discussion is also given to MXenes potential applications in Vacuum assisted filtration, casting method, Hot press method, electrospinning and electrochemical deposition and layer-by-layer assembly for the creation of MXene and MXene derived nanocomposite membranes. Additionally, the discussion is carried forward to give an insight to the modification methods for the construction of MXene-based membrane are described in the literature, including pure or intercalated nanomaterials, surface modifiers and miscellaneous two-dimensional nanomaterials. Furthermore, the review article highlights the potential utilization of MXene and MXene based membranes in separation and purification processes including removal of small organic molecules, heavy metals, oil-water separation and desalination. Finally, the perspective use of MXenes strong catalytic activity and electrical conductivity for specialized applications that are difficult for other nanomaterials to accomplish are discussed in conclusion and future prospectus section of the manuscript. Overall, important information is given to help the communities of materials science and membranes to better understand the potential of MXenes for creating cutting-edge separation and purification membranes.


Asunto(s)
Membranas Artificiales , Nanoestructuras , Purificación del Agua , Nanoestructuras/química , Purificación del Agua/métodos , Grafito/química , Contaminantes Químicos del Agua/química , Nanocompuestos/química , Metales Pesados/química , Filtración/métodos
20.
Chemosphere ; 350: 141182, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38211795

RESUMEN

Nitrate is recognized as a highly impactful water contaminant among various pollutants in water. To address the ever-growing demand for water purification, this work investigates the bimetallic palladium (Pd) and tin (Sn) catalysts, which are electrochemically deposited on stainless steel mesh support (Pd-Sn/SS) for the selective conversion of harmful nitrate (NO3-) into benign nitrogen (N2) gas. Results indicate that the bimetallic composition in Pd-Sn/SS electrodes substantially influenced the reaction route for nitrate reduction as well as the performance of nitrate transformation and nitrogen selectivity. It is found that the electrode prepared from Pd:Sn = 1:1 (mole ratio) demonstrates an outstanding nitrate conversion of 95%, nitrogen selectivity of 88%, and nitrogen yield of 82%, which outperform many reported values in the literature. The electrochemically synthesized bimetallic electrode proposed herein enables a new insight for promoting the reactivity and selectivity of nitrate reduction in water.


Asunto(s)
Nitratos , Paladio , Nitratos/química , Paladio/química , Nitrógeno/química , Oxidación-Reducción , Agua/química
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