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The atomistic and electronic structures of isolated hydrogen states in BeO were studied byab initiocalculations and muonium spectroscopy (SR). Whereas standard density-functional theory with a semi-local GGA functional led to a detailed probing of all possible minimum-energy configurations of hydrogen further calculations with the hybrid HSE06 functional provided improved properties avoiding band-gap and self-interaction errors. Similarly to earlier findings for the other wide-gap alkaline-earth oxide, MgO, hydrogen in BeO is also predicted to be an amphoteric defect with the pinning level, E(), positioned in the mid-gap region. Both donor and acceptor levels were found too deep in the gap to allow for hydrogen to act as a source of free carriers. Whereas, hydrogen in its positively-charged state,, adopts exclusively hydroxide-bond OH configurations,andinstead show a preference to occupy cage-like interstitial sites in the lattice.in particular displays a multitude of minimum-energy configurations: its lowest-energy ground state resembles closely a trapped-atom state with a nearly spherical spin-density profile. In contrast to the strongly ionic MgO,in BeO was further found to stabilise in additional higher-energy elongated-bond OH configurations whose existence should be traced to a partial covalent character of the Be–O bonding. Calculations of the proton-electron hyperfine coupling for allstates showed that the ground-state interstitialconfiguration is dominated by an isotropic hyperfine interaction with a magnitude very close to the vacuum value, a finding corroborated by theSR-spectroscopy data. [ABSTRACT FROM AUTHOR]

This paper evaluated the optimization of natural flocculant in different conditions in a tubular photobioreactor using swine wastewater effluent as culture media in a pilot-scale microalgae production plant. This study aimed to assess the flocculation efficiency of Tanfloc SG via a central composite design (CCD), with varying Tanfloc SG concentration, biomass concentration and pH. Subsequently, the microalgaAcutodesmus obliquuswas cultivated in medium obtained from the recycled recovery of microalgae cells via flocculation with Tanfloc SG. Results showed that the recycled medium after flocculation with Tanfloc SG had a positive effect on the biomass and lipid production ofA. obliquus. [ABSTRACT FROM AUTHOR]