Tailoring of nanostructured material as an electrochemical sensor and sorbent for toxic Cd(II) ions from various real samples

Abstract

The aim of the present study is the fabrication of electrochemical sensor and sorbent for toxic Cd(II) ion using ionimprinting technique on vinyl-functionalized multiwalled carbon nanotube. Multiwalled carbon nanotube-based ion-imprinted polymer (MWCNT-IIP) were synthesized using meth acrylic acid as the functional monomer, N,N′ methylene-bis-acrylamide as the cross linking agent, and potassium peroxo disulphate as an initiator. The template and porogen used were cadmium chloride and water. To know the importance of MWCNT, ion-imprinted polymer without MWCNT was also prepared. For the purpose of comparison, non-imprinted polymers were also synthesized. The synthesized products were analyzed by FT-IR, XRD, TEM, EDAX, and TGA. An electrochemical sensor was made up by modifying platinum electrode with MWCNT-IIP. Experimental factors that control the routine of the sensor were investigated and optimized. Under optimal conditions, a calibration curve was obtained with a detection limit of 0.03 μM by using differential pulse voltammetric technique. Selectivity studies show irrelevant significance with Zn (II), Cu (II), and Ni (II) ions. The feasibility of modified platinum electrode shows a prospective application in real water sample collected from a lake, pigments, cosmetics, and fertilizers. The synthesized nanostructured material is also used for the extraction of Cd(II) ion from real water samples. The maximum adsorption of Cd(II) by various imprinted and non-imprinted sorbents was calculated, and it was found that maximum adsorption takes place at pH 6. The kinetic studies show that the adsorption of Cd(II) increases with time and reaches equilibrium at 70 min and the kinetic data follow pseudo-second-order kinetics. The adsorption data fitted to the Langmuir adsorption model which confirms the monolayer formation of an IIP layer on MWCNT surface. The selectivity co-efficient of the imprinted sorbent shows high selectivity and specificity towards Cd(II) ion than other metal ions.A new method for Cd(II) ion sensing with the advantage of ion-imprinted and electrochemical sensor. The sensor displays lower detection limit compared with the existed methods. MWCNT-IIP sensor displays good selectivity towards Cd(II) ion over other metal ions. Sensor with high sensitivity can be used for sensing and extraction of Cd(II) ion in real samples.

Nanomaterials-Based Ion-Imprinted Electrochemical Sensors for Heavy Metal Ions Detection: A Review

“…The sensing system was able to successfully identify Pb 2+ from a variety of actual samples, including lake water, mining wastewater, food samples and environmental samples such as cosmetics, with a recovery rate of 99%. They fabricated another Cd 2+ -templated sensor on vinyl-functionalized MWCNTs [ 93 ]. Compared with IIP, MWCNTs-IIP had a higher specific surface area, which was because the presence of MWCNTs can effectively enhance the adsorption of Cd 2+ on the adsorbent surface.…”