Kamal Alizadeh; Ziba Yaghouby; Azim Shams
Abstract
The electrochemical property of a recently synthesized ligand, 3-((3-mercaptophenyl) aminomethyl)benzene-1,2-diol has been investigated with construction of a modified carbon paste electrode to find out of mercury ions in real samples. To modify the electrode, paraffin oil and multi-walled carbon nanotubes ...
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The electrochemical property of a recently synthesized ligand, 3-((3-mercaptophenyl) aminomethyl)benzene-1,2-diol has been investigated with construction of a modified carbon paste electrode to find out of mercury ions in real samples. To modify the electrode, paraffin oil and multi-walled carbon nanotubes (MWCNT) were used as binder and modifier respectively. Under the optimized conditions, the electrode exhibits a Nernstian slope of 30.0±0.2 mV per decade for mercury(II) ions over a broad concentration range 1×10-7 to 1×10-1M with a R2 value of 0.996 at pH 4.5 in a 5 sec response time. The detection limit of the method for Hg2+ was 2.3×10−8 mol l−1. The influence of several potentially interfering ions such as K+, Ag+, Cd2+, Ni2+, Ca2+, Cr3+, Pb2+, Cu2+, Co2+, Mg2+, Fe2+, Al3+, La3+ and Fe3+ on the determination of Hg2+ was studied and no significant interference was observed. The proposed modified carbon paste electrode was successfully applied to the determination of mercury ions in real water samples.
Soodabeh Khalili; Ali Asghar Ghoreyshi; Mohsen Jahanshahi; Behnam khoshandam
Abstract
Multiwalled carbon nanotubes (MWCNT) were found to be an effective separation media for purifing CO2 from O2. Significant uptakes of CO2 and O2 were measured at 288 K, 298K and 308 K over the pressure range of 1 to 40 bar using volumetric method in dual sorption vessels. The same shape of isotherms ...
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Multiwalled carbon nanotubes (MWCNT) were found to be an effective separation media for purifing CO2 from O2. Significant uptakes of CO2 and O2 were measured at 288 K, 298K and 308 K over the pressure range of 1 to 40 bar using volumetric method in dual sorption vessels. The same shape of isotherms introduced a common mechanism of adsorption but the amount of CO2 adsorbed on MWCNT is 2 times higher than O2 adsorption. The mass uptake of CO2 and O2 by MWCNT was found to increase with increasing pressure and decreasing temperature. The experimental data was well fitted by the Langmuir and Freundlich model isotherms considering the values of regression correlation coefficients. Following a simple acidic treatment procedure, CO2 and O2 adsorption was increased over range of pressure. The adsorbents was characterized by N2 adsorption isotherm at 77 K, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The effect of temperature and pressure on selectivity obtained from IAST demonstrated that maximum selectivity over the pressure and temperature ranges p = 0.5-5 bar and T = 298–308 K was achieved at 308 K and 5 bar.