A disposable modified screen-printed electrode using egg white/ZnO rice structured composite as practical tool electrochemical sensor for formaldehyde detection and its comparative electrochemical study with Chitosan/ZnO nanocomposite.

In this study, Chitosan/ZnO nanocomposite (Ch/ZnO) and egg white/ZnO rice structured composite was synthesized by simple wet chemical technique and characterised by various techniques. A comparative electrochemical analysis were carried out and determined that egg white/ZnO rice structured composite modified screen printed electrode (SPCE) showed good electrochemical behaviour. The electrochemical activity of egg white/ZnO rice structured composite SPCE was investigated for the oxidation-reduction of formaldehyde in alkaline media using cyclic voltammetry (CV).Their unique electrocatalytic activity for the formaldehyde found to exhibit 254 mV cathodic current response towards low negative potentials. Based on these results, a novel screen printed sensor (Egg white albumin/ZnO rice structured composite) for the determination of formaldehyde was analysed using differential pulse voltammetry (DPV). The sensor response was linear from 0.001 mM to 0.005 mM with limit of detection (LOD) 6.2 nM and their sensitivity was found to be 770.68 mM/µA. The developed electrochemical formaldehyde sensor was successfully applied as working electrode in cyclic voltammetric determination of formaldehyde in urine samples. The sensor is selective, inexpensive, stable over several days and disposable as well as simple to manufacture and operate. The system described here can be easily be adapted to other substrates and used as practical tool for formaldehyde analysis.

Effective removal of malachite green dye from aqueous solution in hybrid system utilizing agricultural waste as particle electrodes.

A comparison study of an electrolytic, adsorption, and a novel hybrid method towards the removal of malachite green (MGD) dye from the aquatic environment utilizing agricultural biomass, Eucalyptus globulus seeds was examined. The synthesized material has been characterized by thermogravimetric analysis, SEM, FTIR, and XRD. The acid-modified biosorbent developed a microporous structure suggesting a suitable removal process of MDG. The hybrid method was carried in an indigenously designed three-phase three-dimensional electrolytic reactor with varying applied voltage (6, 9, and 12 V) with biosorbent serving as particle electrode. The hybrid method gave the highest removal rate at a voltage of 12 V, compared to other methods. Moreover, the dye removal capacity increased with increased voltage, and contact time was optimized at 15 min. The adsorption isotherm was well fitted with Freundlich isotherm and kinetic data represented pseudo-second-order. Intra particle diffusion studies suggested no interference with gradual adsorption from macropores to micropores. The removal efficiency of particles electrodes for 6, 9, and 12 V were 95, 97, and 99.8%, respectively. The higher removal of MDG towards the hybrid system may be assigned to the synergistic effect of electrolytic and adsorption systems. Regeneration studies indicated that the biosorbent can be reused up to ten times without appreciable loss of efficiency.