Simultaneous studies on solar energy storage by CO2 reduction to HCOOH with Brilliant Green dye removal photoelectrochemically

The simultaneous study on photoelectrochemical CO2 reduction with Brilliant Green (BG) dye removal was studied in the present work. Experimental studies were done in aqueous solutions of sodium and potassium based electrolytes using a cathode [Zinc (Zn) and Tin (Sn)] and a common cobalt oxide (Co3O4) anode electrocatalyst. The influence of reaction with electrolyte concentration for the both catalysts was shown clearly with respect to time. The selected electrocatalysts were able to reduce CO2 to formic acid (HCOOH) along with high BG dye removal. With Sn as cathode, the maximum BG dye removal was obtained to be KHCO3–[95.9% (10 min)–0.2 M], NaHCO3–[98.6% (15 min)–0.6 M]. Similarly for Zn, KHCO3–[99.8% (10 min)–0.4 M], NaHCO3–[99.9% (20 min)–0.8 M] were observed respectively. Finally, the results have proven that higher efficiencies for BG dye removal were obtained along with HCOOH formation, which might be a better alternate for water purification and to decrease the atmospheric CO2 concentrations

Effect of copper oxide electrocatalyst on CO2 reduction using Co3O4 as anode

The reduction of carbon dioxide (CO2) to products electrochemically (RCPE) in 0.5 M NaHCO3 and Na2CO3 liquid phase electrolyte solutions was investigated. Cobalt oxide (Co3O4) as anode and cuprous oxide (Cu2O) as the cathode were considered, respectively. The impacts of applied potential with time of reaction during reduction of CO2 to products were studied. The anode and cathode were prepared by depositing electrocatalysts on the graphite plate. Ultra-fast liquid chromatography (UFLC) was used to analyze the products obtained from the reduction of CO2. The feasible way of reduction by applying voltages with current densities was clearly correlated. The results illustrate the capability of electrocatalyst successfully to remove atmospheric CO2 in the form of valuable chemicals. Maximum Faradaic efficiency of ethanol was 98.1% at 2 V and for formic acid (36.6%) at 1.5 V was observed in NaHCO3. On the other hand, in Na2CO3 electrolyte solution maximum efficiency for ethanol was 55.21% at 1.5 V and 25.1% for formic acid at 2 V. In both electrolytes other end products like methanol, propanol, formaldehyde and acetic acid were formed at various applied voltage and output current densities

Al2O3 nanoparticles synthesized using various oxidizing agents: Defluoridation performance

This study concerns the removal of fluoride using aluminium oxide nanoparticles synthesized in the presence of oxidizing agents H2SO4, KMnO4 and K2Cr2O7. The obtained nanoparticles were characterized using TGA, FESEM, EDX and XRD. The almost constant weight loss was observed from the TGA data for the temperature range from 400 to 650 °C. XRD analysis with and without oxidizing agents indicated the crystalline behaviour which increased with increasing the temperature. Prepared Al2O3 nanoparticles exhibited a considerable potential for fluoride adsorption from an aqueous medium in the concentration range of 2–8 mg/l. In this case, around 92% fluoride was adsorbed at pH = 4.7. The equilibrium data were well fitted with Freundlich adsorption isotherm, whereas the adsorption kinetic data followed the pseudo second order model

A novel acorn based adsorbent for the removal of brilliant green

Experiments were carried out to remove brilliant green dye by adsorption technique using a novel adsorbent (activated carbon prepared from acorn). The prepared adsorbent was characterized by BET surface area measurement, FTIR, SEM and elemental analysis. Various parameters such as initial dye concentration, adsorbent dose, initial pH and temperature were studied to observe their effects on the dye adsorption process. At optimum values of the above mentioned parameters, more than 90% removal efficiency was obtained within 30 min at adsorbent dose of 2 g/100 mL for initial dye concentration of 25 mg/L The percentage of dye removal remains almost constant within the pH range of around 6-10. The adsorption of dye was found to follow a pseudo-second-order rate equation. Intra particle diffusion model was studied in order to determine the rate limiting step of the adsorption process. Langmuir isotherm model was fitted the best for the adsorption system with an adsorption capacity of 2.11 mg/g of adsorbent. The present adsorbent may be considered as an alternative adsorbent for the better performance of the brilliant green dye removal from its aqueous medium. (C) 2011 Elsevier B.V. All rights reserved