Multi-walled carbon nanotube and nanosilica chemically modified carbon paste electrodes for the determination of mercury(ii) in polluted water samples

Abstract

Novel carbon paste ion selective electrodes based on 1,4-bis(6-bromohexyloxy)benzene (BHOB) ionophore were constructed in order to determine Hg(II) ion concentration. Multi-walled carbon nanotubes (MWCNTs) and nanosilica modifiers were used for improving the response characteristics of a mercury carbon paste sensors. MWCNTs have good conductivity which helps the transduction of the signal in carbon paste electrode. These potentiometric sensors respond to Hg(II) ions in the wide linear concentration range of 1×10 -1 -1.0×10 -7 and 1.0×10 -1 -1.8×10 -8 mol L -1 with Nernstian slopes of 28.75±0.46 and 29.92±0.15 mV decade -1 of Hg(II) ion and detection limit of 1×10 -7 and 1.8×10 -8 mol L -1 for MWCNTs-CPE (electrode V) and MWCNTs/nanosilica-CPE (electrode VII), respectively. The electrodes were pH independent within the range of 3.0-7.5 and 2.5-8.5, with a fast response time of about 7 and 4 s, and can be used for at least 110 and 145 days without any considerable divergences in the potentials for electrode (V) and electrode (VII), respectively. The proposed sensors thus allowed sensitive, selective, simple, low-cost, and stable electrochemical response to Hg(II) ions in the presence of a large number of alkali, alkaline earth, transition and heavy metal ions. Such abilities promote new opportunities for determining Hg(II) ions in a wide range of real samples. The results obtained were compared well with those obtained using inductively coupled plasma atomic emission spectrometry (ICP-AES).

Novel Amperometric Mercury-Selective Sensor Based on Organic Chelator Ionophore

“…Nevertheless, the detection limit achieved here was much lower than that in [ 43 , 44 ], which also used preconcentration. Furthermore, the sensor developed by us has the advantage of a simpler platform than in [ 9 , 27 , 44 ]. On the other hand, only two sensors used fixed potential techniques for mercury measurement and their architecture does not include carbon nanotubes or ionophores.…”

“…The most used modifiers include metal nanoparticles and films [ 16 , 17 ], polymers [ 18 , 19 ], ion-imprinted polymers [ 20 ], and organic chelators/ionophores [ 21 , 22 , 23 ], such as what is proposed here. Several studies included a combination of these modifiers with carbon nanotubes [ 9 , 24 , 25 , 26 ]; however, in the case of chelators/ionophores, these nanocomposites were mostly used in potentiometric and ion-selective electrodes (ISE) [ 13 , 27 , 28 ]. As far as the literature survey could reveal, only one sensor with this combination was used in voltammetric detection of Hg [ 21 ], and there is no study using electrodes modified with CNT and organic chelator/ionophore as amperometric sensors.…”

Synthesis of thiol amine surfactant for sensor fabrication to determine chromium(III) ions in different water samples

“…A 500 mg pure graphite powder and 5-15 mg of (iphI) ionophore were transferred to mortar and mixed well with plasticizer (0.2 mL of o-NPOE). The modified paste is filled in electrode and kept in distillated water for 24 h before use [35,41,46]. A fresh surface was formed by gently pushing the stainless-steel screw forward and by filter paper polishing the new carbon-paste surface to form a shiny new surface.…”

“…They are more important as biochemical, analytical and antimicrobial reagents. The use of Schiff bases as neutral carriers have been displayed as ion selective electrodes to determine cations such as copper(II) [38][39][40], mercury(II) [41], nickel(II) [42], silver(I) [43], lead(II) [44] and cobalt(II) [13] .…”

Design and construction of an electrochemical sensor for the determination of cerium(iii) ions in petroleum water samples based on a Schiff base-carbon nanotube as an ionophore

“… 10 Potentiometric sensors are a low-cost, easy-to-use technique for analysing hazardous and heavy metal ions in solution, with good selectivity and sensitivity. 11–14 Multiwalled carbon nanotubes (MWCNTs) are allotropes of carbon with a cylindrical nanostructure which have fabulous properties. They are used for nanotechnology, electronics, and other fields of materials science due to its high electrical conductivity, thermal conductivity and surface area.…”