Development of a Modified Screen Printed Electrode for the Determination of Heavy Metals in Water Before and After Remediation With Food Grade Pectin and Citrofortunella Microcarpa Rinds

The rapid increase in population, urbanization, and industrialization, along with inadequate water quality monitoring and wastewater management, contribute heavily to the pollution of water resources. Among the water contaminants of major concern, heavy metals are particularly considered as the most worrisome. Heavy metals tend to accumulate in the tissues of aquatic organisms (Ahmed et al., 2019; Rajeshkumar & Li, 2018; Tabrez et al., 2021) and thus increase in concentration upon moving higher up the food chain. This indicates that once humans ingest these organisms, they have a high risk of experiencing health problems as heavy metals are absorbed into their bodies, leading to the formation of diseases that can be life-threatening. Lead, for instance, can cause kidney and nervous system damage, mental retardation, and cancer (Carolin et al., 2017; Pratush et al., 2018; Vareda et al., 2019; Wani et al., 2020; Zamora-Ledesma et al., 2021). These harmful effects of heavy metals on the human body and the environment require the development of cost-effective technologies to efficiently detect and remove them from water

Silver/Bismuth/Nafion Modified Pencil Graphite Electrode for Trace Heavy Metal Determination

Frequent exposure to heavy metals can cause various health problems (Nagles Arancibia, Rojas, & Segura, 2012; Keawkim, Chuanuwatanakul, Chailapakul, & Motomizu, 2013; Xiao et al., 2014). Among the heavy metals, cadmium and lead have a great impact on biota. Cadmium can cause nephrotoxicity, and even lung cancer, when the amount of exposure to the said metal exceeds 26 µg/kg body mass on a monthly basis (Li et al., 2011; Chen et al., 2014; Aragay & Meroçi, 2012). Lead can greatly affect the nervous system (encephalopathy) and the hormones, and it can trigger some cancers at more than 0.02-3 μg/kg for adults and 0.03 to 9 μg/kg for children on a daily basis (Flora, Gupta, & Tiwari, 2012)

National Research Council of the Philippines (NCRP) lifetime achievement awards

Dr. Arlene Pascasio of the Mathematics faculty and Dr. Shirley Palisoc of the Physics faculty received the National Research Council of the Philippines (NCRP) Lifetime Achievement Awards for their outstanding accomplishments in and contributions to their respective fields of specialization during the 69th NCRP Annual Meeting on the theme Poverty Alleviation through S & T

Gold nanoparticle/hexaammineruthenium/Nafion® modified glassy carbon electrodes for trace heavy metal detection in commercial hair dyes

Gold nanoparticle (AuNP)/hexaammineruthenium(iii) ([Ru(NH3)6]3+)/Nafion® modified glassy carbon electrodes (GCEs) were fabricated and used as working electrodes in the determination of lead and cadmium in commercial hair dyes. The reversibility and stability of the modified electrodes were examined using cyclic voltammetry in which the voltammograms showed reversible peaks. Lead (Pb2+), and cadmium (Cd2+) were detected through anodic stripping voltammetry. The AuNP-[Ru(NH3)6]3+ amount chosen to detect lead and cadmium in hair dyes was 3 mg and 1 mg, respectively, since it was able to simultaneously detect the said metal ions. Furthermore, the peak current and metal concentration displayed a linear relationship with strong correlation values from 0.30 part per million (ppm) to 0.75 ppm for Pb2+ and Cd2+. The limits of detection are 0.0450 ppm and 0.20 ppm for lead and cadmium, respectively. Atomic absorption spectrometry was used to verify the concentrations in each solution. © 2017 The Royal Society of Chemistry

Morphological, thickness and electrochemical analyses of spin-coated [Ru(NH3)6]\u3csup\u3e3+\u3c/sup\u3e /Nafion films

Nafion thin films were fabricated using the spin coating method. Hexaammineruthenium(III) [Ru(NH3)6]3+ was used as the redox mediator and was incorporated in the film. The amount of [Ru(NH3)6]3+ was varied and three different solvents were used. The morphology of the films was investigated and the film thickness was measured using scanning electron microscopy (SEM). The effects of varying the amount of the redox mediator and the solvent type on the viscosity of the coating solution, film thickness and morphology were investigated. The electrochemical properties of the fabricated films were studied using cyclic voltammetry. © 2015, National Institute of Optoelectronics. All rights reserved

Fabrication of a bismuth nanoparticle/Nafion modified screen-printed graphene electrode for: In situ environmental monitoring

Bismuth nanoparticle (BiNP)/Nafion modified screen-printed electrodes were fabricated through screen printing and drop coating. Detection of lead (Pb2+) and cadmium (Cd2+) was performed via anodic stripping voltammetry (ASV). Optimum values of the deposition time (60 seconds) and scan rate (50 mV s-1) were obtained and utilized in the selection of the best BiNP modifier concentration of 1.0 mg. The fabricated electrodes were optimized by cyclic voltammetry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The limit of detection was found to be 280 parts per trillion and 40.34 parts per billion (ppb) for lead and cadmium, respectively. Real samples of filtered tap water, unfiltered tap water, treated wastewater, and water obtained from Manila Bay were analyzed through ASV and atomic absorption spectroscopy (AAS). The Manila Bay water samples contained lead and cadmium levels far beyond safe limits set forth by the U.S. EPA and World Health Organization while trace amounts of lead (1-2 ppb) were detected in the other water samples. The treated wastewater contained the least amount of lead while the unfiltered tap water contained the highest concentration of lead. Nonetheless, these trace amounts are well within tolerance levels set forth by government agencies. The presence of heavy metals in all water samples was validated by AAS analysis. © 2019 The Royal Society of Chemistry

Determination of heavy metals in herbal food supplements using bismuth/multi-walled carbon nanotubes/Nafion modified graphite electrodes sourced from waste batteries

An electrochemical sensor based on graphite electrode extracted from waste zinc-carbon battery is developed. The graphite electrode was modified with bismuth nanoparticles (BiNP), multi-walled carbon nanotubes (MWCNT) and Nafion via the drop coating method. The bare and modified graphite electrodes were used as the working electrode in anodic stripping voltammetry for the determination of trace amounts of cadmium (Cd2+) and lead (Pb2+). The modified electrode exhibited excellent electroanalytical performance for heavy metal detection in comparison with the bare graphite electrode. The linear concentration range from 5 parts per billion (ppb) to 1000 ppb (R2 = 0.996), as well as detection limits of 1.06 ppb for Cd2+ and 0.72 ppb for Pb2+ were obtained at optimized experimental conditions and parameters. The sensor was successfully utilized for the quantification of Cd2+ and Pb2+ in herbal food supplement samples with good agreement to the results obtained by atomic absorption spectroscopy. Thus, the BiNP/MWCNT/Nafion modified graphite electrode is a cost-effective and environment-friendly sensor for monitoring heavy metal contamination. © 2019, The Author(s)

Electrochemical behavior of indium tin oxide electrodes spin coated with Nafion-[Ru(bpy)3]\u3csup\u3e2+\u3c/sup\u3e thin films

© 2015, National Institute of Optoelectronics. All right reserved. Indium tin oxide (ITO) electrodes were modified by depositing Nafion-[Ru(bpy)3]2+ thin films on the electrode surface via the spin coating technique. Scanning electron microscopy (SEM) was used to study the surface morphology of the thin films. Cyclic voltammetry (CV) was used to determine the transport mechanism and the diffusion coefficient of the redox mediators within the films. Different film thicknesses were fabricated by varying the speeds with which the spin coater thinned out the films. SEM micrographs showed a trend of increasing smoothness with increasing thinning rate. The resulting film thickness can be manipulated by simply varying the speed at which the deposited film is thinned out. CV results show successful incorporation of [Ru(bpy)3]2+ within the films. The order of the magnitude of the diffusion coefficients confirmed that the redox mediators were immobilized within the Nafion thin film

Trace level determination of cadmium and lead in coffee (Coffea) using gold nanoparticles modified graphene paste electrode

© 2019, Eesti Pollumajandusulikool. All rights reserved. Gold nanoparticles (AuNP) modified graphene paste electrodes (GPE) were fabricated using graphene powder, gold nanoparticles, and mineral oil. The fabricated electrodes were used as working electrode in anodic stripping voltammetry (ASV) for the determination of trace concentrations of cadmium (Cd2+) and lead (Pb2+). The modified GPE was characterized using scanning electron microscopy and cyclic voltammetry. Optimization of the electrode’s AuNP content and the ASV parameters was performed. It was determined that the GPE modified with 0.5 mg AuNP obtained the highest anodic current peaks for both Cd2+ and Pb2+. The calibration curves obtained using the said electrode showed a linear relationship between heavy metal concentration and peak current and the detection limits were found to be 256 ppb for lead and 267 ppb cadmium. The modified electrode was successful in determining traces of Cd2+ and Pb2+ in coffee samples. The presence of the heavy metals in the samples were verified using atomic absorption spectroscopy