Search

The molecular electric properties and energy of the complexes formed between graphene models of different areas with chrysene, 20 dibenzo[a,h]anthracene and dibenzo[a,h]pyrene were investigated at the density functional theory (DFT) level. Three different sizes (in Å) of graphene models were analyzed: 10 × 10, 15 × 15 and 20 × 20. DFT calculations were performed with the software Materials Studio 5.5, using the functionals HCTH and PBE with Grimme's dispersion correction (PBE-D), within the generalized gradient approximation GGA and numerical DNP basis set. According to results, the PBE-D functional allows a good description of structure, energy and electrical properties of studied systems. In contrast, the HCTH functional poorly reproduced the energy and structures, whereas it allows the description of the complexes through the interaction electric properties. The close relationship between the interaction energy with the interaction polarizability suggests a high contribution of the London dispersion forces. [ABSTRACT FROM AUTHOR]

In this work, the removal of the Cephalexin by Chlorella sp., nonliving modified by extraction of lipids was evaluated. First, the microalga was grown to completing 20 days and later, the biomass of crop was centrifuged and the extraction of lipids was performed. Two adsorption experiments were performed: (1) with nonliving Chlorella sp. (control), and (2) the obtained biomass after lipid extraction. The high antibiotic removal, 71.19% and 82.77% (control), were obtained at the lowest initial concentration. The contact time between the biosorbent and the antibiotic was 2 h. The adsorption isotherm follows the Freundlich model and the obtained maximum absorption capacity was 63.29 mg of antibiotic/g of biosorbent for lipid-extracted biomass, while the control follows best to the Langmuir model with 129.87 mg/g in maximum absorption capacity. In summary, this biosorbent provides a potential alternative in the removal of Cephalexin. [ABSTRACT FROM AUTHOR]