Removal of urea from dilute streams using RVC/nano-NiOx-modified electrode

• Published in: Environmental science and pollution research international 2018-07, Vol.25 (20), p.19898-19907
• Main Authors: Tammam, Reham H., Touny, Ahmed H., Saleh, Mahmoud M.
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Research Article; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-018-2223-8

Reticulated vitreous carbon (RVC), a high surface area electrode (40 cm 2 /cm 3 ), has been modified with nickel oxide nanoparticles (nano-NiO x ) and used for electrochemical oxidation of urea from alkaline solution. For the cyclic voltammetry measurements, the used dimensions are 0.8 cm × 0.8 cm × 0.3 cm. The purpose was to offer high specific surface area using a porous open network structure to accelerate the electrochemical conversion. NiO x nanoparticles have been synthesized via an electrochemical route at some experimental conditions. The morphological, structural, and electrochemical properties of the RVC/nano-NiO x are characterized by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), cyclic voltammetry (CV), and potentiostatic measurements. The fabricated electrode, RVC/nano-NiO x , demonstrates high electrocatalytic activity towards urea oxidation in an alkaline electrolyte. The onset potential of the RVC/nano-NiO x compared to that of the planar GC/NiO x is shifted to more negative value with higher specific activity. The different loadings of the NiO x have a substantial influence on the conversion of urea which has been evaluated from concentration-time curves. The urea concentration decreases with time to a limit dependent on the loading extent. Maximum conversion is obtained at 0.86 mg of NiO x per cm 3 of the RVC matrix.