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A sensor based on graphite nanosheets was fabricated through the electrochemical expansion of a graphite electrode in dimethyl sulfoxide for the sensitive electrochemical determination of enrofloxacin. The modified electrode surface exhibited a distinctive structure of nanoplates, characterized by layer thickness ranging from a few nanometers to ten nanometers. The developed electrode displayed notable electrochemical properties, including a faster charge transfer rate and a larger electrochemically active surface area, which was 1.3 times greater compared to the unmodified electrode. As a result, the sensor improved square wave voltammetric signals for enrofloxacin, exhibiting a 2.4-fold enhancement compared to the unmodified electrode. By optimizing the experimental parameters such as electrode fabrication conditions, pH of analytical solution, and adsorption time for enrofloxacin, the sensor demonstrated good reproducibility and a strong linear correlation over two ranges of enrofloxacin concentrations from 0.05–0.15 μM and 0.1–20 μM. The limit of detection was determined to be 0.002 μM. The sensor was successfully employed for the determination of enrofloxacin in spiked surface water samples before and after treating enrofloxacin by a photocatalytic method. The obtained results exhibited consistency with those obtained using a liquid chromatography-tandem mass spectrometry reference method, and a high recovery rate of 105.5% further confirmed the reliability of the proposed method for enrofloxacin detection. [ABSTRACT FROM AUTHOR]

Ciprofloxacin (Cip), a fluoroquinolone antibiotic, was determined by linear sweep adsorptive stripping voltammetric method using multilayer reduced graphene oxide electrode (m-rGO). The m-rGO electrode was fabricated directly, simply and promptly from graphite platform by potentiostatic technique without further modification. The produced electrode exhibited excellent performance for ciprofloxacin (Cip) determination with a much higher signal of Cip than that on the initial graphite electrode (13.4 times). This dominance of the m-rGO electrode resulted from the large electrochemically active surface area, electrochemical catalysis, suitable functional groups on the electrode surface. Experimental conditions such as the electrode fabrication time, the supporting solution, and accumulation time were optimised to obtain the Cip highest signal. A Cip analytical method established under the optimal conditions had a good linear relationship between the Cip signal with its concentration range from 0.5 to 20 µM (R2 = 0.9953). The method showed a low detection limit (LOD = 0.078 µM), satisfactory reproducibility (RSD = 1.50%), and high accuracy. Cip concentration in a spiked lake water sample determined by the proposed method with acceptable precision (RSD = 5.59%) and trueness (recovery = 94.2–106.3%) was comparable with LC-MS/MS method. [ABSTRACT FROM AUTHOR]

The implementation of climate change adaptation and greenhouse gas emissions (GHGs) mitigation not only results in synergy and co-benefits of climate change adaptation and mitigation but also leads to socioeconomic, environmental, and institutional benefits. The main objective of the study is to develop the methodology to assess the co-benefits of climate change response actions in nationally determined contributions (NDCs) as well as Vietnam's sustainable development goals (SDGs). During this research study, it was found that GHG mitigation can lead to an adaptation rate of 2.9 (on a scale of 5), which is higher than that of climate change adaptation to climate change mitigation (which is a rate of 1.9 on a scale of 5). Most of the overall benefits of GHGs reduction are gained in the Land Use, Land-Use Change, and Forestry (LULUCF) sector. As for the climate change adaptation, the overall benefits can be received most in the agricultural and the rural development sector. Moreover, the implementation of climate change actions also facilitates the achievement of SDGs. [ABSTRACT FROM AUTHOR]

Platinum nanoflowers modified glassy carbon electrodes (PtNFs/GCE) was fabricated simply for lead determination in water samples. The modified electrodes were prepared by electrodeposition in hexachloroplatinic acid solution at constant potential. The influence of deposition time and potential on surface morphology, chemical composition, electrochemical properties of electrode were investigated. At −0.2 V of potential and 150 s of deposition duration, platinum developed as nanoflower shape and scattered densely all over the glassy carbon surface, producing the largest electrochemically active surface areas. The highest differential pulse stripping voltammetry (DPSV) signal of lead was obtained by using the prepared electrode. Under optimized experimental condition of electrolyte, accumulation potential and time, the peak current was found to be linear proportion to lead concentration in range of 1 to 100 μg L−1 (slope=0.371) with a limit of detection of 0.398 μg L−1. The method has good repeatability and reproducibility with relative standard deviations of 1.47 % and 4.83 %, respectively. The modified PtNFs/GCE also demonstrated an excellent long‐term stability with only 9 % decrease in Pb peak current over 30 days. Moreover, the performance of the modified PtNFs/GCE in determination of Pb(II) in two industrial wastewaters was good agreement with data obtained by a graphite furnace atomic absorption spectrometry (GFAAS) method. [ABSTRACT FROM AUTHOR]

We introduce the fabrication and electrochemical application of platinum nanoflower-modified glassy carbon electrode (PtNFs/GCE) for the trace level determination of lead and cadmium using differential pulse anodic stripping voltammetry (DPASV). The modified electrodes have been characterized by EDX, XRD, SEM, and AFM techniques to confirm chemical and physical properties. The effect of potential electrodeposition on the properties of the electrode was investigated. At −0.2 V of potential, platinum developed with a nanoflower shape and dispersed densely all over the glassy carbon surface. In this condition, the highest of lead and cadmium electrochemical signals was clearly observed. The sensor showed wide linearity in the concentration range of 1–100 μg·L−1 with detection limits of 0.408 μg·L−1 and 0.453 μg·L−1 for lead and cadmium ions, respectively. The produced electrodes have good reproducibility with relative standard deviations of 4.65% for lead and 4.36% for cadmium ions. The results demonstrate that this simple, stable, and sensitive sensor is suitable for the simultaneous electrochemical determination of Pb2+ and Cd2+ at trace levels. [ABSTRACT FROM AUTHOR]

This work studies the Pb(II) removal onto bentonite clay modified by hexadecyl trimethyl ammonium bromide (HDTMA). Characterizations of the unmodified and modified materials were performed by using XRD, SEM, TG-DSC, FT-IR, and BET surface area analyses. Factors influencing the uptake of Pb(II) from aqueous solution, such as pH solution , ion strength, uptake time, adsorbent dosage, and initial Pb(II) concentration, were examined. The obtained results showed that bentonite clay was successfully modified by HDTMA, resulting in an increase in its surface area by about 70 %. The Pb(II) adsorption onto modified bentonite clay reached equilibrium at pH = 5.0 after 120 min. Studies within the isotherm and kinetic models demonstrated that the adsorption followed the Sips isotherm and pseudo-second-order kinetic models. The maximum monolayer adsorption capacity calculated from the Langmuir model at 30 °C was 25.8 mg/g, which is much higher than that obtained for the unmodified sample (18.9 mg/g). The FT-IR and TG-DSC analyses indicated that the formation of inner-sphere complexes plays a fundamental role in the mechanism of Pb(II) uptake onto HDTMA-bentonite clay. This mechanism of Pb(II) adsorption was further investigated, for the first time, by using the positron annihilation lifetime (PAL) and electron momentum (EMD) measurements. The PAL and EMD analyses indicated that the existence of Al and Si mono-vacancies in the HDTMA-bentonite should have essential contributions to the adsorption mechanism. In particular, we found a very interesting mechanism that the Pb(II) adsorption should occur inside the interlayer spaces of the HDTMA-bentonite. [Display omitted] • Bentonite clay was modified by HDTMA to enhance the Pb(II) removal. • The Langmuir monolayer adsorption capacity of HDTMA-modified bentonite was 25.8 mg/g. • The mechanisms of Pb(II) adsorption were studied via different analytical methods. • The formation of inner-sphere complexes played a major mechanism in the Pb(II) uptake. [ABSTRACT FROM AUTHOR]