Model for Core−Shell Nanoparticle Formation by Ion-Exchange Mechanism

2008 ◽  
Vol 47 (16) ◽  
pp. 5982-5985 ◽  
Author(s):  
Mani Ethayaraja ◽  
Rajdip Bandyopadhyaya
Keyword(s):  
Ion Exchange ◽  
Exchange Mechanism ◽  
Core Shell ◽  
Nanoparticle Formation

Zinc Oxide/ Silver Sulfide (ZnO/Ag2S) Core-Shell Type Composite for Wide Range Absorption of Visible Spectra: Synthesis and Characterization

2019 ◽  
Vol 25 ◽  
pp. 84-89 ◽  
Author(s):  
Afaf Mohammad Babeer ◽  
Lubna Aamir
Keyword(s):  
Zinc Oxide ◽  
Ion Exchange ◽  
Zno Nanoparticles ◽  
Silver Sulfide ◽  
Exchange Mechanism ◽  
Core Shell ◽  
Sem Image ◽  
Wide Range ◽  
Visible Spectra ◽  
Type Composite

This work presents the synthesis of zinc oxide /silver sulfide (ZnO/Ag2S) core/shell type composite; using combined wet chemical precipitation method and ion exchange mechanism; for wide range absorption of visible spectra by the composite. Synthesis is performed in three steps. In the first step; ZnO nanoparticles (nanocores) are produced, in the second step; ZnS layer is deposited over ZnO nanocores and in the third step; Zn from ZnS is replaced by Ag to form Ag2S shell over ZnO; using ion exchange mechanism. The presence of reflection peaks of ZnO and Ag2S in XRD spectra confirms the formation of ZnO/Ag2S composite. SEM image of ZnO shows the formation of near spherical ZnO nanoparticles of diameter in range 256nm to 584nm with a smooth surface, while SEM image of ZnO/Ag2S composite shows the formation of Ag2S layer over ZnO cores as indicated by rougher and contrasted surface as compared to bare ZnO cores. Also, the size of composite particles became larger than ZnO nanocores (100µm-200µm), which further confirms the formation of Ag2S shell over ZnO nanocores. The optical absorption spectrums of both ZnO and ZnO/Ag2S composite clearly indicate that synthesized composite absorb strongly in UV to IR region of the electromagnetic spectrum as compared to ZnO nanocores; which absorb only in UV region. Therefore, the synthesized composite could be used as a photovoltaic material.

Effectiveness of Calcium Deficiency in Nanosized Hydroxyapatite for Removal of Fe(II), Cu(II), Ni(II) and Cr(VI) Ions from Aqueous Solutions

2019 ◽  
Vol 56 ◽  
pp. 17-27
Author(s):  
Van Dat Doan ◽  
Van Thuan Le ◽  
Hoang Sinh Le ◽  
Dinh Hien Ta ◽  
Hoai Thuong Nguyen
Keyword(s):  
Electron Microscopy ◽  
Ion Exchange ◽  
Aqueous Solutions ◽  
Calcium Deficiency ◽  
Exchange Mechanism ◽  
Precipitation Method ◽  
X Ray ◽  
Transmission Electron ◽  
Bet Method ◽  
Langmuir Isotherm Model

In this work, nanosized calcium deficient hydroxyapatite (nCDHA) was synthesized by the precipitation method, and then utilized as an adsorbent for removal of Fe (II), Cu (II), Ni (II) and Cr (VI) ions from aqueous solutions after characterizing it by various techniques as scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and BET method. A possible structure of synthesized nCDHA was proposed. The adsorption study indicated that the adsorption equilibrium is well fitted with Langmuir isotherm model with the maximum adsorption capacities followed the order of Fe (II) > Cu (II) > Ni (II) > Cr (VI) with the values of 137.23, 128.02, 83.19 and 2.92 mg/g, respectively. The ion-exchange mechanism was dominant for the adsorption of metal ions onto nCDHA at initial metal concentrations lower than 0.01 mol/L. Along with the ion-exchange mechanism, there was an additional precipitation occurred on the surface of nCDHA in the case of Fe (II) and Cu (II) at initial concentrations higher than 0.01 mol/L.

In Situ Study of Fe3Pt–Fe2O3 Core–Shell Nanoparticle Formation

2015 ◽  
Vol 137 (47) ◽  
pp. 14850-14853 ◽  
Author(s):  
Wen-I Liang ◽  
Xiaowei Zhang ◽  
Yunlong Zan ◽  
Ming Pan ◽  
Cory Czarnik ◽  
...  
Keyword(s):  
Core Shell ◽  
Nanoparticle Formation ◽  
In Situ Study

Ion Exchange Mechanism and Isotherms from Deep Bed Performance

1952 ◽  
Vol 20 (12) ◽  
pp. 1842-1846 ◽  
Author(s):  
C. Neale Merriam ◽  
Raymond W. Southworth ◽  
Henry C. Thomas
Keyword(s):  
Ion Exchange ◽  
Exchange Mechanism

Preparation and enhanced photoelectrochemical performance of selenite-sensitized zinc oxide core/shell composite structure

2015 ◽  
Vol 3 (8) ◽  
pp. 4239-4247 ◽  
Author(s):  
Tiantian Hong ◽  
Zhifeng Liu ◽  
Hui Liu ◽  
Junqi Liu ◽  
Xueqi Zhang ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Ion Exchange ◽  
Chemical Synthesis ◽  
Water Splitting ◽  
Low Cost ◽  
Core Shell ◽  
Nanorod Arrays ◽  
Photoelectrochemical Performance ◽  
Vertically Aligned ◽  
Shell Composite

A fast, versatile and low-cost hydrothermal chemical synthesis based on ion-exchange has been used to deposit a shell of cupric selenite onto vertically aligned zinc oxide nanorod arrays with a buffer layer of zinc selenite for photoelectrochemical water splitting.

Sign in / Sign up

Export Citation Format

Share Document