Guidelines for the use and interpretation of adsorption isotherm models: A review.

Metal-based nanoparticles have been extensively investigated for a set of biomedical applications. According to the World Health Organization, in addition to their reduced size and selectivity for bacteria, metal-based nanoparticles have also proved to be effective against pathogens listed as a priority. Metal-based nanoparticles are known to have non-specific bacterial toxicity mechanisms (they do not bind to a specific receptor in the bacterial cell) which not only makes the development of resistance by bacteria difficult, but also broadens the spectrum of antibacterial activity. As a result, a large majority of metal-based nanoparticles efficacy studies performed so far have shown promising results in both Gram-positive and Gram-negative bacteria. The aim of this review has been a comprehensive discussion of the state of the art on the use of the most relevant types of metal nanoparticles employed as antimicrobial agents. A special emphasis to silver nanoparticles is given, while others (e.g., gold, zinc oxide, copper, and copper oxide nanoparticles) commonly used in antibiotherapy are also reviewed. The novelty of this review relies on the comparative discussion of the different types of metal nanoparticles, their production methods, physicochemical characterization, and pharmacokinetics together with the toxicological risk encountered with the use of different types of nanoparticles as antimicrobial agents. Their added-value in the development of alternative, more effective antibiotics against multi-resistant Gram-negative bacteria has been highlighted.

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Metal-based nanoparticles as antimicrobial agents: an overview.

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Fundamentals Of Powder Diffraction And Structural Characterization Of Materials

The removal of the most prevalent heavy metal ions [cadmium(II), lead(II), copper(II), and zinc(II)] by adsorption on Scots pine (Pinus sylvestris L.) biochar and Silver birch (Betula pendula) biochar has been investigated, following the determination of physical and chemical adsorption properties of biochar. The efficiency of adsorption of heavy metal ions [cadmium(II), lead(II), copper(II), and zinc(II)] on biochar was studied at different concentrations of heavy metals [onefold maximum contaminant level, twofold maximum contaminant level, fivefold maximum contaminant level (in accordance with the requirements set out in the Water Framework Directive 2000/60/EC), dosages of biochar (1.6–140 g), and biochar types (Scots pine (P. sylvestris L.) biochar and Silver birch (B. pendula) biochar produced at slow and fast pyrolysis) at constant pH of leaching solution, temperature, and contact time. Adsorption capacity of Scots pine (P. sylvestris L.) biochar and Silver birch (B. pendula) biochar was assessed by the application of extended Freundlich isotherm. In this study, biochar was evaluated as a potential adsorbent to efficiently reduce concentration of heavy metal ions in metal-contaminated water. The maximum adsorption capacity were reached of copper(II) on Silver birch (B. pendula) biochar (128.7 µg g−1) and of zinc(II) on Scots pine (P. sylvestris L.) biochar (107.0 µg g−1). Adsorption capacity of lead(II) on Silver birch (B. pendula) and Scots pine (P. sylvestris L.) biochar varied from 1.29 to 3.77 and from 2.37 to 4.49 µg g−1, respectively.

/pdf/biochar-as-adsorbent-for-removal-of-heavy-metal-ions-cadmium-18utpzi9hd.pdf

Biochar as adsorbent for removal of heavy metal ions [Cadmium(II), Copper(II), Lead(II), Zinc(II)] from aqueous phase

Hydroxyl and sulfate radical mediated degradation of ciprofloxacin using nano zerovalent manganese catalyzed S2O82

Green synthesis of silver nanoparticles using terrestrial fern (Gleichenia Pectinata (Willd.) C. Presl.): characterization and antimicrobial studies

Investigation of the sorption potential of rice husk, an agricultural waste, as an adsorbent was carried out. The rice husk was modified with orthophosphoric acid and was used for adsorption of lead (II) ions (Pb2

https://downloads.hindawi.com/archive/2013/842425.pdf

Sorption of from Aqueous Solution unto Modified Rice Husk: Isotherms Studies

Synthesis of nanoscale zerovalent manganese (nZVMn) by chemical reduction was carried out in a single pot system under inert environment. nZVMn was characterized using a combination of analytical techniques: Ultraviolet–Visible Spectroscopy, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Transmission Electron Microscopy, Energy Dispersive X-ray, BET surface area and Point of Zero Charge. The adsorption physicochemical factors: pH, contact time, adsorbent dose, agitation speed, initial copper ion concentration and temperature were optimized. The kinetic data fitted better to Pseudo second-order, Elovich, fractional power and intraparticle diffusion models and their validity was tested by three statistical models: sum of square error, Chi-square (χ
 2) and normalized standard deviation (Δq). Seven of the two-parameter isotherm models [Freundlich, Langmuir, Temkin, Dubinin–Kaganer–Raduskevich (DKR), Halsey, Harkin–Jura and Flory–Huggins] were used to analyse the equilibrium adsorption data. The Langmuir monolayer adsorption capacity (Q
 max = 181.818 mg/g) obtained is greater than other those of nano-adsorbents utilized in adsorption of copper ions. The equilibrium adsorption data were better described by Langmuir, Freundlich, Temkin, DKR and Halsey isotherm models considering their coefficient of regression (R
 2 > 0.90). The values of the thermodynamic parameters: standard enthalpy change ∆H° (+50.27848 kJ mol−1), standard entropy change ∆S° (203.5724 J mol−1 K−1) and the Gibbs free energy change ∆G° revealed that the adsorption process was feasible, spontaneous, and endothermic in nature. The performance of this novel nanoscale zerovalent manganese (nZVMn) suggested that it has a great potential for effective removal of copper ions from aqueous solution.

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A novel zerovalent manganese for removal of copper ions: synthesis, characterization and adsorption studies

Silver nanoparticle synthesis by Acalypha wilkesiana extract: phytochemical screening, characterization, influence of operational parameters, and preliminary antibacterial testing.

Adewumi O. Dada

Papers

Green synthesis of silver nanoparticles using terrestrial fern (Gleichenia Pectinata (Willd.) C. Presl.): characterization and antimicrobial studies

Sorption of from Aqueous Solution unto Modified Rice Husk: Isotherms Studies

A novel zerovalent manganese for removal of copper ions: synthesis, characterization and adsorption studies

Silver nanoparticle synthesis by Acalypha wilkesiana extract: phytochemical screening, characterization, influence of operational parameters, and preliminary antibacterial testing.

Rhodamine B dye sequestration using Gmelina aborea leaf powder.