A Novel Electrochemical Sensing Platform for the Sensitive Detection and Degradation Monitoring of Methylene Blue

Abstract

Methylene blue is a toxic dye that is extensively used as a colorant in textile industries. Industrial effluent containing methylene blue, when drained into water bodies without proper treatment, poses a serious threat to aquatic and human lives. In order to protect the biocycle, various methods have been established to detect and remove hazardous dyes from aqueous systems. Electrochemical methods are preferred, owing to their characteristic features of simplicity, portability, potential selectivity, cost effectiveness, and rapid responsiveness. Based on these considerations, an electrochemical sensor consisting of amino-group-functionalized, multi-walled carbon nanotubes (NH2-fMWCNTs) immobilized on a glassy carbon electrode (GCE) was developed for the sensitive detection of methylene blue in aqueous solutions. The performance of the designed sensor was analyzed by electrochemical impedance spectroscopy, cyclic voltammetry, and square wave voltammetry. The developed sensing tool demonstrated promising features of sensitivity, selectivity, stability, fast responsiveness, and the ability to work with a very small volume of the analyte, i.e., in microliters, for analysis. Amino groups rich in electrons provide a negative charge to multi-walled carbon nanotubes, which significantly enhances the electrocatalytic activity of NH2-fMWCNTs for cationic dyes such as methylene blue. Using the designed sensing platform, a linear calibration plot with a limit of detection of 0.21 nM was obtained for methylene blue under optimized conditions. The designed sensor was also employed to monitor the extent and kinetics of the degradation of methylene blue. Titania nanoparticles were used for photocatalytic degradation, and the kinetics of degradation was monitored by both UV-Visible spectroscopic and electrochemical methods. The results revealed more than 95% removal of methylene blue in a time span of just 30 min.

Selective Aptamer Modification of Au Surfaces in a Microelectrode Sensor Array for Simultaneous Detection of Multiple Analytes

“…This result is in reasonable agreement with previously reported literature for this ATP E-AB sensor on a 2 mm Au disk electrode . It was also observed that the peak shifted to a more positive potential with increasing ATP concentration (Figure a), which was attributed to a decrease in the solution pH. , …”

“…24 It was also observed that the peak shifted to a more positive potential with increasing ATP concentration (Figure 1a), which was attributed to a decrease in the solution pH. 33,34 The DA aptasensor had a K d value of 8 μM, an LOD of 0.1 μM, and a linear range of 0.1−10 μM, which is within the physiologically relevant concentrations of DA, i.e., the normal range is 0.1−1 μM, 35 while for patients treated with L-DOPA, the range is elevated to 0.9−6 μM. 36 The ST sensor had an LOD of 0.5 μM, a linear range of 0.5−10 μM, and a K d value of 14 μM.…”

A Comprehensive Review on Adsorption, Photocatalytic and Chemical Degradation of Dyes and Nitro-Compounds over Different Kinds of Porous and Composite Materials

“…Among the approaches mentioned above, the electrochemical degradation route is more expensive than other approaches for dye degradation [ 199 ]. The main reason for reduced implementation of the electrochemical approach is high energy consumption, the requirement for more chemicals, and costly equipment [ 200 , 201 ]. Other challenges in implementing the electrochemical approach are the production of metabolites and other by-products during these processes.…”

Magnetically modified Schiff base‐Pd complex: An efficient heterogeneous catalyst for Suzuki–Miyaura cross‐coupling and dyes degradation reaction

“…Industrial wastewater contains harmful compounds that have an inimical impact on humans, animals, plants, and aquatic life. [38,39] It is crucial to remove the pollutants from wastewater or convert it into less harmful chemicals because it lowers the biological oxygen demand of water when directly discharged into water bodies, particularly those that contain methylene blue (MB). [40] Another dye that causes infections of the gastrointestinal tract, skin, respiratory tract, and eyes is rhodamine B (RhB), which is categorized as a neurotoxin and carcinogenic dye for humans.…”