Insights on the effect of process conditions on the optical properties of silver ion exchanged soda-lime silicate glass.

The effects of ion exchange time and temperature on the optical properties and plasmonic response of silver ion exchanged soda-lime silicate glass were investigated using scanning electron microscopy (SEM) in energy dispersive spectrometry (EDS) configuration, m-lines spectroscopy, photoluminescence (PL) spectroscopy, and UV-visible absorption spectroscopy. SEM analyses in EDS mode provided profiles of silver oxide molar concentration. These profiles were directly correlated to the silver diffusion coefficient using an adjustment procedure. The effective indices of ion exchanged glasses measured by the standard prism coupling technique (m-lines) allowed access to refractive index distributions in ion exchange regions. These ion-exchanged glasses underwent evaluation to determine their potential suitability for use in multimode planar systems. The PL results acquired after ion exchange demonstrated that the creation of Ag0atoms from Ag+ions was responsible for the decline and quenching of PL intensity at ion exchange times and temperatures increase. Silver nanoparticles were generated in the samples subjected to ion exchange at 480 °C without the need for post-exchange treatments. The emergence of the surface plasmon resonance band around 427 nm in the optical absorption spectra confirmed the formation of Ag nanoparticles in annealed glasses. Estimates of the UV-visible absorption spectra indicated an average size of silver nanoparticles ranging from 1.8 to 2.4 nm.

One-step electrochemical elaboration of SnO2 modified electrode for lead ion trace detection in drinking water using SWASV.

A facile method was proposed for the elaboration of an electrochemical sensor for heavy metal's trace detection by using square wave anodic stripping voltammetry (SWASV); this method is based on a simple anodic conversion of tin electrode into Sn/SnO2 modified electrode. Both electrochemical and physico-chemical techniques were used to confirm the modification process and better understand the electrode's behavior. Then, depending on the operating conditions, the response signal was studied and adjusted in order to obtain optimal sensor performance. When optimized, the proposed method reached a lowest detection limit (LOD) of 2.15 µg L-1 (0.0104 µM), and quantification limit (LOQ) of 5.36 µg L-1 (0.0259 µM), in linearity range between from 6.2 and 20.7 µg L-1. Additionally, after having used the elaborated electrode for ten successive measurements, the repeatability remains very high with an RSD of approximately 5.3%; furthermore, ten other species appear to have very slight effect on Pb(II) detection. Finally, for the method validation, the proposed electrode was able to sense different lead concentration integrated in a local bottled spring water by showing recovery levels ranging from 103.8 to 108.4%.

Heterogeneous degradation of amoxicillin in the presence of synthesized alginate-Fe beads catalyst by the electro-Fenton process using a graphite cathode recovered from used batteries.

Iron alginate beads (Fe-Alg) were prepared, characterized and implemented for the degradation of amoxicillin (AMX) by the heterogeneous electro-Fenton process using a graphite cathode recovered from used batteries. Scanning electron microscopy (SEM) showed that (Fe-Alg) beads have a spherical shape and the results of energy dispersive spectrometric (EDS) revealed the presence of iron in (Fe-Alg). Optimization of the operating parameters showed that a complete degradation of AMX was achieved within 90 min of heterogeneous electro-Fenton treatment by operating under these conditions: initial AMX concentration: 0.0136 mM, I = 600 mA, [Na2SO4] = 50 mM, pH = 3, T = 25 °C, ω = 360 rpm. The corresponding chemical oxygen demand (COD) abatement was 50%. Increasing the contact time increased the COD abatement to 85.71%, after 150 min of heterogeneous electro-Fenton treatment. The results of the kinetic study by using nonlinear methods demonstrated that the reaction of AMX degradation obeyed to a pseudo-second-order kinetic. Iron content of 4.63% w/w was determined by the acid digestion method. After 5 cycles of use, the Alg-Fe catalyst depletion was only 8%. Biodegradability was remarkably improved after electro-Fenton pretreatment, since it increased from 0.07 initially to 0.36. The heterogeneous electro-Fenton process had efficiently eliminated AMX and it increased the biodegradability of the treated solution.