scholarly journals Gold Nanoparticle Assemblies by Metal Ion−Pyridine Complexation and Their Rectified Quantized Charging in Aqueous Solutions

2002 ◽  
Vol 106 (8) ◽  
pp. 1903-1908 ◽  
Author(s):  
Shaowei Chen ◽  
Renjun Pei ◽  
Tongfeng Zhao ◽  
Daniel J. Dyer
Keyword(s):  
Aqueous Solutions ◽  
Gold Nanoparticle ◽  
Metal Ion ◽  
Nanoparticle Assemblies

Visualization of Localized Intense Optical Fields in Single Gold−Nanoparticle Assemblies and Ultrasensitive Raman Active Sites

Nano Letters ◽  
2006 ◽  
Vol 6 (10) ◽  
pp. 2173-2176 ◽  
Author(s):  
Kohei Imura ◽  
Hiromi Okamoto ◽  
Mohammad K. Hossain ◽  
Masahiro Kitajima
Keyword(s):  
Gold Nanoparticle ◽  
Active Sites ◽  
Optical Fields ◽  
Nanoparticle Assemblies

scholarly journals Comparison between Different Keratin-composed Biosorbents for the Removal of Heavy Metal Ions from Aqueous Solutions

2002 ◽  
Vol 20 (4) ◽  
pp. 393-416 ◽  
Author(s):  
Fawzi Banat ◽  
Sameer Al-Asheh ◽  
Dheaya‘ Al-Rousan
Keyword(s):  
Aqueous Solutions ◽  
Human Hair ◽  
Metal Ion ◽  
Ph Value ◽  
Freundlich Isotherm ◽  
Operating Conditions ◽  
Ion Uptake ◽  
Chicken Feathers ◽  
Initial Ph ◽  
Metal Ion Uptake

This study examined and compared the ability of chicken feathers, human hair and animal horns, as keratin-composed biosorbents, for the removal of Zn2+ and Cu2+ ions from single metal ion aqueous solutions under different operating conditions. The three biosorbents investigated in this study were all capable of adsorbing Zn2+ and Cu2+ ions from aqueous solutions. The biosorbent showing the highest uptake of Zn2+ and Cu2+ ions was animal horns. Chicken feathers showed a higher Cu2+ ion uptake and a lower Zn2+ ion compared to human hair. Increasing the initial concentration of Zn2+ or Cu2+ ions, or increasing the initial pH value, increased the metal ion uptake. Such uptake decreased when the temperature was raised from 25°C to 50°C for all adsorbent/metal ion combinations except for Zn2+ ion/human hair where the uptake increased with temperature. It was demonstrated that the addition of NaCl salt to the metal ion solution depressed the metal ion uptake. The Freundlich isotherm model was found to be applicable to the adsorption data for Cu2+ and Zn2+ ions.

What Controls the Optical Properties of DNA-Linked Gold Nanoparticle Assemblies?

2000 ◽  
Vol 122 (19) ◽  
pp. 4640-4650 ◽  
Author(s):  
James J. Storhoff ◽  
Anne A. Lazarides ◽  
Robert C. Mucic ◽  
Chad A. Mirkin ◽  
Robert L. Letsinger ◽  
...  
Keyword(s):  
Optical Properties ◽  
Gold Nanoparticle ◽  
Nanoparticle Assemblies

A multi-site mechanism model for studying Pb and Cu retention from aqueous solutions by Fe-Mg-rich clays

Clay Minerals ◽  
2018 ◽  
Vol 53 (2) ◽  
pp. 175-192 ◽  
Author(s):  
Z. Kypritidou ◽  
A. Argyraki
Keyword(s):  
Aqueous Solutions ◽  
Metal Ion ◽  
Methodological Approach ◽  
Synergetic Effect ◽  
Sorption Isotherms ◽  
Superior Performance ◽  
Isotherm Models ◽  
Sufficient Information ◽  
Retention Mechanisms ◽  
Clay Materials

ABSTRACTThe retention mechanisms of metal ions during interaction of clay with metal-rich aqueous solutions is usually investigated by sorption isotherms. Although classical isotherm models may provide sufficient information about the characteristics of the solid–liquid system, they do not distinguish among the various retention mechanisms. This study presents a methodological approach of combining batch experiment data and geochemical modelling for the characterization of the interaction of Mg-Fe-rich clay materials with monometallic solutions of Pb and Cu. For this purpose, a palygorskite clay (PCM), an Fe-smectite clay (SCM) and a natural palygorskite-Fe-smectite mixed clay (MCM) were assessed for their effectiveness as metal ion sorbents. The sorption capacity of the materials follows the order MCM > SCM > PCM and ranges between 27.6–52.1 mg g–1for Pb and 7.7–17.6 mg g–1for Cu. Based on the experimental results that allowed the speciation calculations, fitting of sorption isotherms and the investigation of relationships between protons, Mg and the metals studied we suggest that a combination of sorption mechanisms occurs during the interaction of clay materials with metal solutions. These involve surface complexation, ion exchange and precipitation of solid compounds onto the solid surface. A three-term isotherm model was employed to quantify the role of each of the above mechanisms in the overall retention process. The superior performance of mixed clay among the materials tested is attributed to the synergetic effect of exchange in the interlayer and specific sorption on the clay edges.

scholarly journals Adsorption Study of Cu2+ Ions from Aqueous Solutions by Bael Flowers (Aegle marmelos)

2020 ◽  
Vol 11 (4) ◽  
pp. 11891-11904
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Metal Ion ◽  
Low Cost ◽  
Sem Analysis ◽  
Ion Concentration ◽  
Maximum Adsorption Capacity ◽  
Aegle Marmelos ◽  
Batch Mode ◽  
Initial Ph

In the present study, batch mode adsorption was carried out to investigate the adsorption capacity of dried bael flowers (Aegle marmelos) for the adsorptive removal of Cu(II) ions from aqueous solutions by varying agitation time, initial metal concentration, the dose of adsorbent, temperature, and initial pH of the Cu(II) ion solution. The percentage removal of 98.7% was observed at 50 ppm initial metal ion concentration, 0.5 g/100.00 cm3 adsorbent dosage, within the contact time of 120 minutes at 30 ºC in the pH range of 4 – 7. The sorption processes of Cu(II) ions was best described by pseudo-second-order kinetics. Langmuir isotherm had a good fit with the experimental data with 0.97 of correlation coefficient (R2), and the maximum adsorption capacity obtained was 23.14 mg g-1 at 30 ºC. The results obtained from sorption thermodynamic studies suggested that the adsorption process is exothermic and spontaneous. SEM analysis showed tubular voids on the adsorbent. FTIR studies indicated the presence of functional groups like hydroxyl, –C-O, –C=O, and amide groups in the adsorbent, which can probably involve in metal ion adsorption. Therefore, dried bael flowers can be considered an effective low-cost adsorbent for treating Cu(II) ions.

Metal Ion Chelates of Lipophilic Alkyl Diazinyl Ketoximes as Hydrolytic Catalysts

1999 ◽  
Vol 64 (7) ◽  
pp. 1159-1179 ◽  
Author(s):  
Radek Cibulka ◽  
František Hampl ◽  
Tomáš Martinů ◽  
Jiří Mazáč ◽  
Sonja Totevová ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Metal Ion ◽  
Hydrolytic Activity ◽  
Hexadecyltrimethylammonium Bromide ◽  
Diphenyl Phosphate ◽  
Hydrolysis Of ◽  
Metal Ligand

A series of lipophilic dodecyl hetaryl ketoximes (hetaryl = pyridin-2-yl, pyridazin-3-yl, pyrimidin-2-yl, pyrimidin-4-yl, pyrazin-2-yl as well as their methyl hetaryl homologues was synthesized and hydrolytic activity of their chelates with Co2+, Ni2+, Cu2+ and Zn2+ in a micellar matrix of hexadecyltrimethylammonium bromide or in homogeneous aqueous solutions was investigated using 4-nitrophenyl acetate, 4-nitrophenyl hexanoate and 4-nitrophenyl diphenyl phosphate as model substrates. While Co2+ and Cu2+ chelates are almost inactive, those of Ni2+ and Zn2+ exhibit considerable activity. None of the studied chelates promotes hydrolysis of the used phosphate. The effective species are chelates of the metal : ligand stoichiometry 1 : 3 and 1 : 1 with Ni2+ and Zn2+, respectively, when the ester cleavage proceeds in the micellar matrix. The 1 : 2 stoichiometry was found in aqueous solutions of Ni2+ and Zn2+ chelates of methyl ketoximes.

Removal of Pb(II) and Cd(II) From Aqueous Solution by Adsorption Using Agrowaste-Modified Kaolinite Clay

2021 ◽  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Metal Ion ◽  
Low Cost ◽  
Ion Concentration ◽  
Kaolinite Clay ◽  
Adsorbent Surface ◽  
Initial Adsorption ◽  
Adsorption Rates

This study showed that kaolinite clay modified with Moringa oleifera pods is a promising low cost adsorbent for the removal of metals from aqueous solution because the resultant composite has higher adsorption capacities, and hence a better metal ions removal efficiency. The efficiencies of these adsorbents for the removal of Pb (II) and Cd (II) ions from aqueous solutions were studied as a function of pH, time, adsorbate concentration and adsorbent dose. Adsorption results showed that pH did significantly affect removal of heavy metal ions between pH 3 and 6. Increasing contact time and initial metal ion concentration increased the sorption capacity of the adsorbent for the metal ions. Adsorbent dosage indicated mainly surface phenomena involving sharing of electrons between the adsorbent surface and the metal ion species. The adsorption of metal ions from aqueous solutions of both metal ions at different initial metal ion concentrations reduced the initial adsorption rates of the adsorption of Pb (II) and Cd (II) by unmodified and modified kaolinite clay.

What Controls the Optical Properties of DNA-Linked Gold Nanoparticle Assemblies?*

2020 ◽  
pp. 293-324
Author(s):  
James J. Storhoff ◽  
Anne A. Lazarides ◽  
Robert C. Mucic ◽  
Chad A. Mirkin ◽  
Robert L. Letsinger ◽  
...  
Keyword(s):  
Optical Properties ◽  
Gold Nanoparticle ◽  
Nanoparticle Assemblies

Plasmonic control of drug release efficiency in agarose gel loaded with gold nanoparticle assemblies

2021 ◽  
pp. 253-264
Author(s):  
Luca Moretti ◽  
Andrea Mazzanti ◽  
Arianna Rossetti ◽  
Andrea Schirato ◽  
Laura Polito ◽  
...  
Keyword(s):  
Drug Release ◽  
Gold Nanoparticle ◽  
Agarose Gel ◽  
Nanoparticle Assemblies
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