CuO@MWCNTs nanocomposite as non-enzyme electrochemical sensor for the detection of Malathion in seawater

Molecularly Imprinted Electrochemical Sensor Based on MWCNTs/GQDs for the Detection of Sulfamethazine in Aquaculture Seawater

In this work, a novel molecularly imprinted electrochemical sensor was proposed based on molecular imprinting technology for the detection of sulfamethazine. A glassy carbon electrode was modified with a composite material of carbon nanotubes and graphene quantum dots to effectively improve sensitivity. The molecularly imprinted electrochemical sensor was then prepared by electropolymerization using sulfamethazine as the template and o-phenylenediamine as the functional monomer on the modified electrode. Under optimal measurement conditions, electrochemical tests of different sulfamethazine concentrations (0.5 μM-200 μM) showed excellent linearity and a detection limit of 0.068 μM. In addition, the sensor demonstrated satisfactory selectivity, stability, and reusability. Furthermore, the sensor was applied to the spiked analysis of sulfamethazine in grouper aquaculture water, achieving recovery rates between 95.4% and 104.8%, with a relative standard deviation (RSD) of less than 4.14%. These results indicated that the developed method was effective for the analysis of sulfamethazine in aquaculture seawater, providing a new approach for the detection of antibiotic residues in seawater samples.

Developing a highly sensitive electrochemical sensor for malathion detection based on green g-C3N4@LiCoO2 nanocomposites

Nowadays, developing pesticide-free agriculture is highly demanded by society. The development of electrochemical sensors to monitor and control pesticides is an effective step toward this desired goal. The current research has faced this issue by modifying of glassy carbon electrodes (GCEs) with green g-C3N4@LiCoO2 nanocomposites to probe malathion, an organophosphate pesticide. The g-C3N4@LiCoO2 modified GCE showed higher current than the net GCE, as a result of improved electrocatalytic performance of the modified GCE to oxidize malathion. Increased malathion concentration enhanced the malathion oxidation anodic peak current at +410 mV caused by the g-C3N4@LiCoO2 modified GCE. The developed probe showed an excellent linear response for malathion detection in the 5-120 nM (R 2 = 0.994) range and recorded a limit of detection of 4.38 nM. Besides, the modified GCE reveals considerable stability and reproducibility, which offers a cost-effective, sensitive, and selective electrode for malathion probing.

Biosorption of acid brown 14 dye to mandarin-CO-TETA derived from mandarin peels

Several agronomic waste-materials are presently being widely used as bio-adsorbents for the treatment of toxic wastes such as dyes and heavy metals from industrial activities, which has resulted in critical global environmental issues. Therefore, there is a need to continue searching for more effective means of mitigating these industrial effluents. Synthetic aromatic dyes such as Acid Brown (AB14) dye are one such industrial effluent that is causing a serious global issue owing to the huge amount of these unsafe effluents released into the ecosystem daily as contaminants. Consequently, their confiscation from the environment is critical. Hence, in this study, Mandarin-CO-TETA (MCT) derived from mandarin peels was utilized for the removal of AB14 dyes. The synthesized biosorbent was subsequently characterized employing FTIR, TGA, BET, and SEM coupled with an EDX. The biosorption of this dye was observed to be pH-dependent, with the optimum removal of this dye being noticed at pH 1.5 and was ascribed to the electrostatic interaction between the positively charged sites on the biosorbent and the anionic AB14 dye. The biosorption process of AB14 dye was ideally described by employing the pseudo-second-order (PSO) and the Langmuir (LNR) models. The ideal biosorption capacity was calculated to be 416.67 mg/g and the biosorption process was indicative of monolayer sorption of AB14 dye to MCT biosorbent. Thus, the studied biosorbent can be employed as a low-cost activated biomass-based biosorbent for the treatment of AB14 dyes from industrial activities before they are further released into the environment, thus mitigating environmental contamination.

Detection of Environmentally Harmful Malathion Pesticides Using a Bimetallic Oxide of CuO Nanoparticles Dispersed over a 3D ZnO Nanoflower

Super-sensitive malathion detection was achieved using a nonenzymatic electrochemical sensor based on a CuO/ZnO-modified glassy carbon electrode (GCE). Due to the high affinity between the Cu element and the sulfur groups in malathion, the developed CuO-ZnO/GCE sensor may bond malathion with ease, inhibiting the redox signal of the Cu element when malathion is present. In addition to significantly increasing the ability of electron transfer, the addition of 3D-flower-like ZnO enhances active sites of the sensor interface for the high affinity of malathion, giving the CuO-ZnO/GCE composite an exceptional level of sensitivity and selectivity. This enzyme-free CuO-ZnO/GCE malathion sensor demonstrates outstanding stability and excellent detection performance under optimal operating conditions with a wide linear range of malathion from 0 to 200 nM and a low detection limit of 1.367 nM. A promising alternative technique for organophosphorus pesticide (OP) determination is offered by the analytical performance of the proposed sensor, and this method can be quickly and sensitively applied to samples that have been contaminated with these pesticides.