Co-pyrolysis of fly ash with sewage sludge for PCDD/F removal.

Fly ash generated from municipal waste incineration (MWI) contains various toxic substances, and it has to be properly treated before disposal or reuse. Water washing and thermal pyrolysis can improve the destruction efficiency of PCDD/Fs in fly ash generated from municipal solid waste incinerators. Since sulfur oxides and nitrogen compounds generated by the heating of the sewage sludge poison the catalytic active sites for PCDD/Fs formation on fly ash surface, co-pyrolysis of fly ash with sewage sludge effectively inhibits precursor formation and de novo synthesis reaction, resulting in the great reduction of PCDD/F formation. The results of the pyrolysis at 350 °C show that the PCDD/Fs removal efficiencies based on mass concentration are over 99%. The results at 350 °C of different reaction times show that the reaction time of 10 min is sufficient to reach the European End of Waste criteria (≤ 20 pg TEQ/g) when the ratio of fly ash/sewage sludge is controlled at 1:1.

InGaN light emitting solar cells with a roughened N-face GaN surface through a laser decomposition process.

InGaN-based light-emitting solar cell (LESC) structure with an inverted pyramidal structure at GaN/sapphire interface was fabricated through a laser decomposition process and a wet crystallographic etching process. The highest light output power of the laser-treated LESC structure, with a 56% backside roughened-area ratio, had a 75% enhancement compared to the conventional device at a 20 mA operating current. By increasing the backside roughened area, the cutoff wavelength of the transmittance spectra and the wavelength of the peak photovoltaic efficiency had a redshift phenomenon that could be caused by increasing the light absorption at InGaN active layer.