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In this study, boron-doped diamond nanoparticles modified on the surface of a screen-printed electrode (SPE) were prepared for the sensitive and selective determination of Sb3+ using square wave voltammetry. The effect of electrochemical parameters such as the type of supporting electrolyte, pH, signal per background, and scan rate on the sensitivity of the sensor for the detection of Sb3+ was investigated. Under optimized conditions with an amplitude of 0.05 V, a frequency of 50 Hz, and an E-step of 0.05 V, the square wave voltammogram between -1.0 and 1.0 V gave a limit of detection of 2.41 × 10-8 M for an Sb3+ concentration range from 0.19 to 0.59 µM. The method was used to determine Sb3+ ions in river water with satisfactory results. The modified electrode displayed benefits such as high sensitivity and selectivity, long-term stability, easy preparation, and wide linear range. [ABSTRACT FROM AUTHOR]

The rising concentration of carbon dioxide (CO2) as one of the greenhouse gases in the atmosphere is a major source of worry. Electrochemical reduction of CO2 is one of many ways to convert CO2 gas into usable compounds. An electrochemical technique was applied in this study to reduce CO2 using a boron-doped diamond (BDD) working electrode modified with MXene (Ti3C2Tx) material to improve electrode performance. MXene concentrations of 0.5 mg/mL (MXene-BDD 0.5), 1.0 mg/mL (MXene-BDD 1.0), and 2.0 mg/mL (MXene-BDD 2.0) were drop-casted onto the BDD surface. MXene was effectively deposited on top of the BDD surface, with Ti weight loads of 0.12%, 4.06%, and 7.14% on MXene-BDD 0.5, MXene-BDD 1.0, and MXene-BDD 2.0, respectively. The modified working electrode was employed for CO2 electroreduction with optimal CO2 gas aeration. The existence of the MXene substance in BDD reduced the electroreduction overpotential of CO2. For the final result, we found that the MXene-BDD 2.0 electrode effectively generated the most formic acid product with a maximum reduction potential as low as −1.3 V (vs. Ag/AgCl). [ABSTRACT FROM AUTHOR]

An ionic liquid (IL) is a compound, composed of a cation, an anion and an alkyl, which has low volatility and good extraction properties. The combination of an ionic liquid and dispersive liquid-liquid microextraction with a GC-FID instrument, used for the determination of n-nitrosodipropylamine (NDPA), is an appropriate, accurate, easy and fast method. The following optimal parameters of the analysis have been established: ionic liquid [C6MIM] [PF6], dispersing solvent volume 6 µL, 6 µL volume of solvent extract and sample volume 8 ml. The correlation coefficient of this method for concentrations from 2.0 to 10.0 g/L was 0.999. The detection limit for this method is 123 g/mL with an average accuracy of 95.02 % and coefficient of variation of 0.03 % - 2.38 %. The method is developed to detect NDPA in salted fish samples of 1.12 g/L. [ABSTRACT FROM AUTHOR]

Organic template free hierarchical ZSM-5 were synthesized using desilication. X-Ray Diffraction (XRD), Fourier Transform Infra Red (FTIR) spectrometry, and N2 adsorption/desorption analytical techniques were applied to characterize the physicochemical properties of the solid synthesized. Hierarchical ZSM-5 of a molar composition of 100SiO2:1.25Al2O3:1800H2O was obtained at a hydrothermal temperature of 175°C for 36 h. The analytical results showed that the hierarchical ZSM-5 had a mesopore surface area, a pore volume, and a pore diameter of 42.752 m²/g, 0.186 cc/g, and 3.810 nm, respectively. [ABSTRACT FROM AUTHOR]

Increasing the concentration of carbon dioxide gas (CO2) in the atmosphere is a problem that must be addressed in modern society. A promising alternative solution to overcome this problem is to convert CO2 into fuel and value-added chemical compounds such as formic acid (HCOOH). This study addresses this concern by electrochemical method to reduce CO2 using a boron-doped diamond (BDD) electrode-modified SnO-SnO2/Ti3C2Tx material which acts as a catalyst in improving the performance of the working electrode. The SnO-SnO2/Ti3C2Tx material in this study has three various concentrationsof SnO-SnO2/Ti3C2Tx 0.05 g/mL, SnO-SnO2/Ti3C2Tx 0.1 g/mL, and SnO-SnO2/Ti3C2Tx 0.2 g/mL, which were dropped onto the surface of the BDD electrode and characterized using cyclic voltammetry (CV), scanning electron microscope-energy dispersive X-ray (SEM-EDX), and X-ray photoelectron spectroscopy (XPS). Electroreduction of CO2 in this study was able to produce the highest concentration of HCOOH by using a SnO-SnO2/Ti3C2Tx-BDD 0.2 g/mL electrode at a reduction potential of − 0.903 V (vs. NHE). The resulting HCOOH has a concentration of 21.32 ppm with a faraday efficiency of 94.06%. The SnO-SnO2/Ti3C2Tx-BDD electrode was then compared with the bare-BDD and BDD-MXene electrodes at the same reduction potential of − 0.903 V (vs. NHE). The concentration of HCOOH produced by bare-BDD was 7.63 ppm with a faraday efficiency of 63.28% and for BDD-MXene that is 9.81 ppm with a faraday efficiency of 79.87%. Thus, BDD electrode modified with SnO-SnO2/Ti3C2Tx is effective to reducing the overpotential of CO2 electroreduction and producing a higher efficiency of HCOOH.Graphical Abstract: Increasing the concentration of carbon dioxide gas (CO2) in the atmosphere is a problem that must be addressed in modern society. A promising alternative solution to overcome this problem is to convert CO2 into fuel and value-added chemical compounds such as formic acid (HCOOH). This study addresses this concern by electrochemical method to reduce CO2 using a boron-doped diamond (BDD) electrode-modified SnO-SnO2/Ti3C2Tx material which acts as a catalyst in improving the performance of the working electrode. The SnO-SnO2/Ti3C2Tx material in this study has three various concentrationsof SnO-SnO2/Ti3C2Tx 0.05 g/mL, SnO-SnO2/Ti3C2Tx 0.1 g/mL, and SnO-SnO2/Ti3C2Tx 0.2 g/mL, which were dropped onto the surface of the BDD electrode and characterized using cyclic voltammetry (CV), scanning electron microscope-energy dispersive X-ray (SEM-EDX), and X-ray photoelectron spectroscopy (XPS). Electroreduction of CO2 in this study was able to produce the highest concentration of HCOOH by using a SnO-SnO2/Ti3C2Tx-BDD 0.2 g/mL electrode at a reduction potential of − 0.903 V (vs. NHE). The resulting HCOOH has a concentration of 21.32 ppm with a faraday efficiency of 94.06%. The SnO-SnO2/Ti3C2Tx-BDD electrode was then compared with the bare-BDD and BDD-MXene electrodes at the same reduction potential of − 0.903 V (vs. NHE). The concentration of HCOOH produced by bare-BDD was 7.63 ppm with a faraday efficiency of 63.28% and for BDD-MXene that is 9.81 ppm with a faraday efficiency of 79.87%. Thus, BDD electrode modified with SnO-SnO2/Ti3C2Tx is effective to reducing the overpotential of CO2 electroreduction and producing a higher efficiency of HCOOH. [ABSTRACT FROM AUTHOR]