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A low-cost and durable BiVO4 photoelectrode (PE) is herein synthesized to improve the separation of the electron and hole pair in photoelectrochemical applications. A new synthesis method was envis...

The synthesis of the poly(4-vinylpyridine-co-ethylvinylbenzene) resin is investigated and its performance to remove Cr(VI) from aqueous solutions is evaluated as a function of pH using batch and fixed bed column adsorptions. The rate of Cr(VI) removal is observed to increase as the pH solution shifts to acidic conditions due to an enhanced protonation of the 4-vinylpyridine group in the polymer, which favors its electrostatic attraction with Cr(VI) oxyanions. This finding is supported with Density Functional Theory (DFT) calculations, revealing that the interaction between $${\text{CrO}}_{4}^{{2 - }}$$ (predominant species at pH 6) due to a higher charge delocalization arising in the O atoms. Experimental isotherms are approximated with the Langmuir and Radke-Prausnitz adsorption models. This former approach generates the best fitting to the data, whereby it was incorporated into a nonlinear transient model to account for the Cr(VI) adsorption in a fixed bed, and evaluating its capacity to predict experimental adsorption data. The model enables to infer that the resin presents a fast kinetic for Cr(VI) sorption, and the Cr(VI) intra-particle diffusion across the adsorbent pores is the rate-determining step for sorption.

Sixteen imidazolium based chiral ionic liquids (CILs) containing Br − and BF 4 − anions, derived from both enantiomers of phenylethylamine, were synthesized. The imidazole ring was constructed through a condensation reaction of formaldehyde, glyoxal and ammonium hydroxide in aqueous media resulting in a simple, versatile and environmentally friendly protocol. The CILs were synthesized with propyl, butyl, pentyl or hexyl alkyl substituents, which provoke a change of the physicochemical properties that were evaluated (glass transition temperature, thermal stability, optical rotation, ionic conductivity, electrochemical window and toxicity). The 1-alkyl-3-(1-phenylethyl) imidazolium tetrafluoroborate ([C n peim]BF 4 ) family showed good thermal stability, large electrochemical window, low toxicity at moderate concentrations, and adequate viscosity. Therefore, these CILs are a good candidates to be used in asymmetric reactions and may be a viable alternative to organic solvents.