Iron molybdenum oxide-modified screen-printed electrode: Application for electrocatalytic oxidation of cabergoline

3D rhombohedral microcrystals metal-organic frameworks for electrochemical and fluorescence sensing of tetracycline

Zirconium-based metal-organic frameworks (MOF) exhibiting 3D rhombohedral microcrystals were synthesized by the solvothermal method. The structure, morphology, composition, and optical properties of the synthesized MOF were carried out using different spectroscopic, microscopic, and diffraction techniques. Synthesized MOF was rhombohedral in shape and the cage structure of these crystalline molecules was the active binding site of the analyte, tetracycline (TET). The electronic property and size of the cages are chosen such that a specific interaction with TET was observed. Sensing of the analyte was demonstrated by both the electrochemical and fluorescent techniques. The MOF had significant luminescent properties and exhibited excellent electro-catalytic activity due to embedded zirconium metal ions. An electrochemical and fluorescence sensor was fabricated towards TET where TET binds via hydrogen bond to MOF, and causes fluorescence quenching due to the transfer of electrons. Both approaches exhibited high selectivity and good stability in the presence of interfering molecules such as antibiotics, biomolecules, and ions; and showed excellent reliability in tap water and wastewater sample analysis.

Adsorptive removal of Ag/Au quantum dots onto covalent organic frameworks@magnetic zeolite@arabic gum hydrogel and their catalytic microwave-Fenton oxidative degradation of Rifampicin antibiotic

Recent progress in nanotechnology via incorporation of small particle size as quantum dots (QDs) (1-10 nm) in many industrial activities and commercial products has led to significant undesired environmental impacts. Therefore, QDs removal from wastewater represents an interesting research topic with a lot of challenges for scientists and engineers nowadays. In this work, the coagulative removal of metal quantum dots as silver and gold from industrial water samples is explored. A novel biosorbent was assembled via binding of covalent organic frameworks (COFs) with magnetic zeolite and Arabic gum hydrogel (COFs@MagZ@AGH) as a promising removal material for Ag-QDs and Au-QDs. This was fully characterized by EDX, SEM, TEM, FT-IR, XPS, XRD and surface area and applied in coagulative removal of Au-QDs and Ag-QDs in presence of several experimental factors as pH, presence of other electrolytes, stirring time, initial QDs concentration, coagulant dosage, and temperature in order to optimize the removal processes. At optimum conditions, COFs@MagZ@AGH was able to recover 99.19% and 87.57% of Ag-QDs and Au-QDs QDs, respectively via chemical adsorption mechanism with perfect fitting to pseudo-second order model. Reuse of the recovered Ag/Au-QDs@COFs@MagZ@AGH as efficient catalysts in catalytic degradation of Rifampicin antibiotic (Rf) from water was additionally investigated and optimized via microwave-Fenton catalysts with excellent oxidative degradation efficiency (100%). Reusability and applicability of the biosorbent (COFs@MagZ@AGH) and catalysts (Ag/Au-QDs@COFs@MagZ@AGH) in real industrial water samples were also explored and successfully accomplished.

A simple and sensitive approach for the electrochemical determination of amaranth by a Pd/GO nanomaterial-modified screen-printed electrode

It is essential to develop easy-to-use sensors towards a better monitoring of food additives so that human health can be positively influenced. A type of critical food additive that is widely used in making soft drinks and diverse foodstuff is called amaranth. This study aimed at presenting a novel Pd/GO nanomaterial-modified screen-printed electrode (Pd/GO/SPE), which is responsible for providing a sensing interface during the process of specifying the electrochemical features of amaranth. The morphology and structure of the Pd/GO nanomaterial was investigated by Fourier-transform infrared spectroscopy, thermal gravimetric analysis, X-ray photoelectron spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning transmission electron microscopy, and high-resolution transmission electron microscopy. When the optimized conditions was adjusted, Pd/GO/SPE proved to be a capable sensor for conducting a very sensitive sensing towards the amaranth under a common working situation of 575 mV. In this regard, it was embarked on measuring some of the sensor features, including its sensitivity, linear dynamic range, and detection limit for amaranth with the values of 0.0948 μA μM-1, 0.08 μM-360.0 μM and 30.0 nM were obtained, respectively.

Developments and applications of nanomaterial-based carbon paste electrodes

This review summarizes the progress that has been made in the past ten years in the field of electrochemical sensing using nanomaterial-based carbon paste electrodes. Following an introduction into the field, a first large section covers sensors for biological species and pharmaceutical compounds (with subsections on sensors for antioxidants, catecholamines and amino acids). The next section covers sensors for environmental pollutants (with subsections on sensors for pesticides and heavy metal ions). Several tables are presented that give an overview on the wealth of methods (differential pulse voltammetry, square wave voltammetry, amperometry, etc.) and different nanomaterials available. A concluding section summarizes the status, addresses future challenges, and gives an outlook on potential trends.

Recent developments in conducting polymers: applications for electrochemistry

Scientists have categorized conductive polymers as materials having strongly reversible redox behavior and uncommon combined features of plastics and metal. Because of their multifunctional characteristics, e.g., simplistic synthesis, acceptable environmental stability, beneficial optical, electronic, and mechanical features, researchers have largely considered them for diverse applications. Therefore, their capability of catalyzing several electrode reactions has been introduced as one of their significant features. A thin layer of the conducting polymer deposited on the substrate electrode surface can augment the electrode process kinetics of several solution species. Such electrocatalytic procedures with modified conducting polymer electrodes can create beneficial utilization in diverse fields of applied electrochemistry. This review article explores typical recent applications of conductive polymers (2016–2020) as active electrode materials for energy storage applications, electrochemical sensing, and conversion fields such as electrochemical supercapacitors, lithium-ion batteries, fuel cells, and solar cells.

Scientists have categorized conductive polymers as materials having strongly reversible redox behavior and uncommon combined features of plastics and metal.