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Biohydrometallurgy is generally considered as a green technology for the recycling of industrial solid waste. In this study, an indigenous fungal strain named Y5 with the ability of high-yielding organic acids was isolated and applied in bioleaching of waste printed circuit boards (PCBs). The strain Y5 was identified as Penicillium chrysogenum by morphological and molecular identification. Meanwhile, we investigated that an optimal set of culturing conditions for the fungal growth and acids secretion was 15 g/L glucose with initial pH 5.0, temperature 25°C and shaking speed 120 rpm in shaken flasks culture. Moreover, three bioleaching processes such as one-step, two-step and spent medium processes were conducted to extract copper from waste PCBs. Spent medium bioleaching showed higher copper extraction percentage and it was 47% under 5%(w/v) pulp density. Transmission electron microscope (TEM) observation combining with energy dispersive analysis of X-rays (EDAX) showed that the leached metal ions did not obviously damage the hypha cells. All above results indicated that P . chrysogenum strain Y5 has the tolerance to metal ions, suggesting its potential in recycling of metals from waste PCBs in industry. [ABSTRACT FROM AUTHOR]

The effects of secondary magnetic field originating from a permanent magnet on deposition rate, crystalline structure and photoelectric properties of Al-doped ZnO (AZO) films prepared by RF magnetron sputtering were systematically investigated. X-ray diffraction demonstrated that the films prepared using a secondary magnetic field were well aligned and textured along (002) orientation. SEM micrographs revealed that the grains became more compact and homogeneous with fewer defects in comparison to those grown by conventional magnetron sputtering (CMS). The deposition rate and lowest resistance of films prepared in the presence of a secondary magnetic field were 19.9nm/min and 12.88Ω/, respectively. The average transmittance of all films in visible range was over 85% when the sputtering time was less than 60min. The secondary magnetic field had a small influence on the transmittance of the films, but it caused a larger blue shift of the absorbance edge. Numerical simulations showed that the secondary magnetic field significantly changed the intensity and distribution of the transverse magnetic field in discharge space and caused a higher target current density. [ABSTRACT FROM AUTHOR]