In recent years, the interest in waste water treatment increased to preserve the environment. The objective of this study is the removal of lead and cadmium ions from aqueous solution by treated Phragmites biomass (TPB). TPB was characterized by using Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray analysis (EDS) which indicates the presence of functional groups that may be responsible of metal adsorption such as hydroxyl, carbonyl, sulfonate and carboxylate. Characterization by scanning electron microscopy (SEM) and surface area analysis using the Brunauer–Emmett–Teller method (BET) illustrated that TPB is nonporous with a small surface area. The influences of various experimental factors were investigated; the proposed method recommended the extraction of Pb⁺² and Cd⁺² metal ions by TPB at pH 5.0. A contact time of 60 and 45 min was required for the adsorption 50 mL (50 ppm) Pb⁺² and Cd⁺² respectively to reach equilibrium when 0.10 g TPB was used. The optimum TPB dosage was 0.20 g for adsorption both metal ions when adsorbate solution was 50 mL (50 ppm). Particle sizes of 0.125–0.212 mm showed the best metal ion removal of both metal ions. Thermodynamic study illustrated that both metal ions correlate more with Langmuir isotherm. Furthermore, chemisorption of Pb⁺² and Cd⁺² on TPB was more likely according to kinetic study data.

Cladophora biomass has been treated and used for the removal of Lead and Cadmium ions from water, and the characterization of Cladophora biomass by Fourier transform infrared (FTIR) and energydispersive x-ray analysis (EDS) indicate the presence of functional groups of different components such as polysaccharides, amino acids, fatty acids and others. Scanning electron microscopy (SEM) and surface area analysis (BET) confirm nonporous algal biomass with small surface area. The parameters affecting metal ions removal from water such as adsorbent-solution contact time, pH of metal ion solution, algal biomass dose and mesh sizes have been studied. Isothermal study has been applied using Freundlich and Langmuir models.

The application of the powdered biomass of Zygophyllum coccineum plants for the removal of Pb and Cu ions from water has been investigated. Energy-dispersive X-ray analysis and Fourier-transform infrared characterization revealed the presence of functional groups related to various components of the biomass. Surface area analyses and scanning electron microscopy demonstrated the nonporous and low surface area nature of the powdered biomass. The contact times required for Pb and Cu ion removal to reach equilibrium were 60 and 45 min, respectively. The optimum pH for the highest percentage of removal was 4. In 50 mL Cu ion solution (50 ppm), 0.2 g of powdered biomass was sufficient for Cu ion removal, while at similar concentrations, Pb ion removal increased significantly with the increase in the biomass. The best particle size for the removal of both ions was 0.212–0.50 mm. Pb ion removal was found to correlate with the Langmuir model, while Cu correlated with the Freundlich model. Langmuir isothermal model revealed adsorption capacities of 25.5 and 14.8 mg g⁻¹ for Pb and Cu ions, respectively. This study shows that Z. coccineum biomass is efficient in removing Pb and Cu from water.

Purpose: To determine vildagliptin concentration in a pharmaceutical formulation using voltammetric analysis techniques, and optimize the parameters affecting the techniques. Method: Four types of voltammetry techniques, including cyclic voltammetry (CV), differential pulse voltammetry (DPV), square wave voltammetry (SWV), and linear sweep voltammetry (LSV), were employed to measure vildagliptin. Platinum (Pt) and glassy carbon (GC) were used as working electrodes, while KNO₃ (1 M) and phosphate buffer (NaH₂PO₄/H₃PO₄) pH 6.8 were used to study optimal voltammetric analysis conditions. Results: CV results indicate that vildagliptin is electroactive and exhibits irreversible redox cycles while LSV results showed an oxidation peak current around 1.35 V that has high sensitivity and a linear standard regression line correlation coefficient of 0.9995. In addition, LSV results showed that vildagliptin has a lower limit of detection of ~ 0.241 mM and a limit of quantification of ~ 0.802 mM. Finally, the results show that vildagliptin has an acceptable level of recovery of 104.1 % and a relative standard deviation of 0.52 % for the commercially available vildagliptin tablets used in this study. Conclusion: The accuracy and precision of all applied voltammetric techniques for vildagliptin analysis are within accepted limits stipulated in pharmaceutical analysis quality control guidelines. The recommended method for vildagliptin analysis is LSV with Pt as the working electrode and KNO₃ (1 M) as the supporting electrolyte. Keywords: Vildagliptin, Cyclic voltammetry, Square wave voltammetry, Differential pulse voltammetry, Linear sweep voltammetry

In the present work TiO2 nanotubes (TNT) have been synthesized by alkaline hydrothermal transformation. Then they have been doped with Gd element. Characterizations of doped and undoped TNT have been done with TEM and SEM. The chemical composition was analyzed by EDX, Raman and FTIR spectroscopy. The crystal structure was characterized by XRD. Carbon paste electrode has been fabricated and mixed with Gd doped and undoped TNT to form a nanocomposite working electrode. Comparison of bare carbon paste electrode and Gd doped and undoped TNT carbon paste electrode for 1.0 ×10−3 M K4 [Fe(CN)6] voltammetric analysis; it was observed that Gd doped TNT modified electrode has advantage of high sensitivity. Gd doped TNT modified electrode has been used as working electrode for itopride assay in a pharmaceutical formulation. Cyclic voltammetry analysis showed high correlation coefficient of 0.9973 for itopride (0.04–0.2 mg/mL) with a limit of detection (LOD) and limit of quantitation values (LOQ) of 2.9 and 23.0 μg.mL−1 respectively.