• Energy Research

The APEX (aqueous photochemistry of environmentally occurring xenobiotics) software computes the phototransformation kinetics of compounds that occur in sunlit surface waters. It is free software based on Octave, and was originally released in 2014. Since then, APEX has proven to be a remarkably flexible platform, allowing for the addressing of several environmental problems. However, considering APEX as a stand-alone software is not conducive to exploiting its full potentialities. Rather, it is part of a whole ecosystem that encompasses both the software and the laboratory protocols that allow for the measurement of substrate photoreactivity parameters. Coherently with this viewpoint, the present paper shows both how to use APEX, and how to experimentally derive or approximately assess the needed input data. Attention is also given to some issues that might provide obstacles to users, including the extension of APEX beyond the simple systems for which it was initially conceived. In particular, we show how to use APEX to deal with compounds that undergo acid–base equilibria, and with the photochemistry of systems such as stratified lakes, lakes undergoing evaporation, and rivers. Hopefully, this work will provide a reference for the smooth use of one of the most powerful instruments for the modeling of photochemical processes in freshwater environments. All authors have read and agreed to the published version of the manuscript.

The APEX (aqueous photochemistry of environmentally occurring xenobiotics) software computes the phototransformation kinetics of compounds that occur in sunlit surface waters. It is free software based on Octave, and was originally released in 2014. Since then, APEX has proven to be a remarkably flexible platform, allowing for the addressing of several environmental problems. However, considering APEX as a stand-alone software is not conducive to exploiting its full potentialities. Rather, it is part of a whole ecosystem that encompasses both the software and the laboratory protocols that allow for the measurement of substrate photoreactivity parameters. Coherently with this viewpoint, the present paper shows both how to use APEX, and how to experimentally derive or approximately assess the needed input data. Attention is also given to some issues that might provide obstacles to users, including the extension of APEX beyond the simple systems for which it was initially conceived. In particular, we show how to use APEX to deal with compounds that undergo acid–base equilibria, and with the photochemistry of systems such as stratified lakes, lakes undergoing evaporation, and rivers. Hopefully, this work will provide a reference for the smooth use of one of the most powerful instruments for the modeling of photochemical processes in freshwater environments. All authors have read and agreed to the published version of the manuscript.

Porous activated carbons (AC-AN and AC-AO) for toluene adsorption were prepared starting from brewer’s grain biomass pretreated with microorganisms (Aspergillus niger van Tieghem for AC-AN and Aspergillus oryzae RIB40 for AC-AO). The structures and chemical properties of the three activated carbon materials (AC-AN, AC-AO, and AC that was not pretreated with microorganisms) were characterized by N2 adsorption–desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The adsorption behavior of the three activated carbons for toluene was studied and correlated with the physical and chemical properties of these materials. The results suggested that the activated carbons prepared by microbial pretreatment had a rougher morphology, higher specific surface area, richer pore structure, fewer oxygen-containing functional groups on the surface, and better adsorption performance for toluene (increased by 31.5% and 18.3% with AC-AN and AC-AO, respectively) compared with the untreated activated carbon (AC). The Thomas model was used to fit the toluene adsorption data, indicating that the rich pore structure accelerated the kinetic process of toluene adsorption. Therefore, appropriate microbial pretreatment of the feedstock that is used to prepare activated carbon can effectively improve its adsorption capacity towards toluene.

Porous activated carbons (AC-AN and AC-AO) for toluene adsorption were prepared starting from brewer’s grain biomass pretreated with microorganisms (Aspergillus niger van Tieghem for AC-AN and Aspergillus oryzae RIB40 for AC-AO). The structures and chemical properties of the three activated carbon materials (AC-AN, AC-AO, and AC that was not pretreated with microorganisms) were characterized by N2 adsorption–desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The adsorption behavior of the three activated carbons for toluene was studied and correlated with the physical and chemical properties of these materials. The results suggested that the activated carbons prepared by microbial pretreatment had a rougher morphology, higher specific surface area, richer pore structure, fewer oxygen-containing functional groups on the surface, and better adsorption performance for toluene (increased by 31.5% and 18.3% with AC-AN and AC-AO, respectively) compared with the untreated activated carbon (AC). The Thomas model was used to fit the toluene adsorption data, indicating that the rich pore structure accelerated the kinetic process of toluene adsorption. Therefore, appropriate microbial pretreatment of the feedstock that is used to prepare activated carbon can effectively improve its adsorption capacity towards toluene.

Fluorescence spectroscopy is very useful for the characterisation of organic matter in natural water samples. The importance of protein-like fluorescence might be enhanced by several events induced by warming in natural waters such as lake water.

Fluorescence spectroscopy is very useful for the characterisation of organic matter in natural water samples. The importance of protein-like fluorescence might be enhanced by several events induced by warming in natural waters such as lake water.

The charge-transfer complexes have scientific relevance because this type of molecular interaction is at the basis of the activity of pharmacological compounds and because the absorption bands of the complexes can be used for the quantification of electron donor molecules. This work aims to assess the stability of the charge-transfer complexes between the electron acceptor 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and two drugs, procaine and atenolol, in acetonitrile and ethanol. The stability of DDQ in solution and the time required to obtain the maximum complex formation were evaluated. The stoichiometry and the stability of the complexes were determined, respectively, by Job's plot method and by the elaboration of UV-vis titrations data. The latter task was carried out by using the non-linear global analysis approach to determine the equilibrium constants. This approach to data elaboration allowed us to overcome the disadvantages of the classical linear-regression method, to obtain reliable values of the association constants and to calculate the entire spectra of the complexes. NMR spectra were recorded to identify the portion of the donor molecule that was involved in the interaction. The data support the participation of the aliphatic amino groups in complex formation and exclude the involvement of the aromatic amine present in the procaine molecule.