Sanjay P. Kamble

Emulsion ionic liquid membranes (EILMs) for removal of Pb(II) from aqueous solutions

Ionic liquids (ILs) are playing increasingly important roles in the membrane separation processes. The present manuscript discusses the removal of Pb(II) ions from aqueous solution using an emulsion ionic liquid membrane (EILM) process. Initially, the emulsion liquid membrane (ELM) was prepared by stirring strip phase (sulphuric acid) and organic phase (surfactant: span 80, extractant: D2EHPA, diluent: hexane) together under high speed agitation. Note that, the parameters of the ELM process such as emulsification speed, pH of the feed phase, treat ratio, extractant and surfactant concentrations were studied for the maximum removal of Pb(II) ions. The role of IL was explored by adding hydrophobic IL, octylmethylimidazole hexafluorophosphine ([OMIM][PF6]), in the organic phase. The performance of ELM with and without IL was compared on the basis of stability, enrichment factor and the removal efficiency for Pb(II). The results showed that the percentage of Pb(II) extraction was complete by the emulsion membrane with IL (EILM) in comparison to the 97% achieved by neat ELM. Further, the stability and the enrichment factor of the EILM were found to be 2–3 times greater than that of the ELM. The FT-IR spectroscopic analysis revealed that bond interactions between IL and membrane phase components avoided the coalescence of internal phase droplets and enhanced the emulsion stability. The results obtained in this work support the use of the IL [OMIM][PF6] as both a stabilizer and carrier for the overall improvement of the ELM process.

Photocatalytic Degradation of Phenolics by N-Doped Mesoporous Titania under Solar Radiation

In this study, nitrogen-doped mesoporous titania was synthesized by templating method using chitosan. This biopolymer chitosan plays the dual role of acting as a template (which imparts mesoporosity) and precursor for nitrogen. BET-SA, XRD, UV-DRS, SEM, and FTIR were used to characterize the photocatalyst. The doping of nitrogen into TiO2 lattice and its state was substantiated and measured by XPS. The photocatalytic activity of the prepared N-doped mesoporous titania for phenol and o-chlorophenol degradation was investigated under solar and artificial radiation. The rate of photocatalytic degradation was observed to be higher for o-chlorophenol than that of phenol. The photodegradation of o-chlorophenol was 98.62% and 72.2%, while in case of phenol, degradation to the tune of 69.25% and 30.58% was achieved in solar and artificial radiation. The effect of various operating parameters, namely, catalyst loading, pH, initial concentration and the effect of coexisting ions on the rate of photocatalytic degradation were studied in detail.

Photocatalytic Degradation of Pharmaceuticals Pollutants Using N-Doped TiO2 Photocatalyst: Identification of CFX Degradation Intermediates

Abstract The N-doped TiO2 photocatalyst was synthesized by the sol–gel method and characterized in detail in terms of its morphology, structure and composition. The prepared N-doped TiO2 exhibited polycrystalline structure having particle sizes of around 50–120 nm and rod-shaped geometry. The N-doped TiO2 was subsequently used for the photocatalytic degradation (PCD) of pharmaceutical micropollutants, namely ciprofloxacin HCl (CFX), naproxen (NPX) and paracetamol (PARA) and it was found that the rate of degradation of CFX and NPX is higher than that of PARA. To verify the beneficial effect of N-doped TiO2 for PCD of CFX, similar experiments were carried out using commercially available Aeroxide P-25 TiO2. It was observed that N-doped TiO2 was more efficient than Aeroxide® P-25 TiO2. It was also found that the PCD of CFX in the presence of N-doped TiO2 was highly efficient under the solar radiation as compared with artificial radiation. The effect of various operating parameters, such as adsorption of CFX, pH of the aqueous solution, effect of co-existing ions on PCD of CFX, was investigated using artificial radiation and optimum conditions were established. The intermediates formed during the PCD of CFX were identified using liquid chromatography tandem mass chromatography (LC-MS/MS). The presented results demonstrate that N-doped TiO2 photocatalyst shows excellent photocatalytic activity in the visible region for the degradation of pharmaceutical pollutants.