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Stainless steel pickling sludge (SSPS) is a noxious solid waste containing heavy metals (Fe, Cr, Mn, and Ni). Herein, an ultrafast ultrasonic-assisted leaching (UAL) extraction method for heavy metals from SSPS is proposed. The effects of key leaching factors, including acid lixiviant, acid dosage, leaching time, liquid-to-solid ratio, and leaching temperature, on the leaching efficiency of Fe, Cr, Ni and Mn in SSPS were systematically studied, followed by the theoretical optimization by response surface methodology. The leaching efficiencies of Fe, Mn, Ni, and Cr were significantly enhanced to 98.6%, 90.74%, 90.83%, and 92.25% within 15 min, which were nearly nine times higher than the acid leaching process. The ultrasonic burst broke up the SSPS and increased the contact area (mass transfer effect) of the heavy metal leaching reaction. In addition, kinetic and thermodynamic studies shown that sonochemical action could significantly promote the initial leaching efficiency of heavy metals. This work provided a super-fast method to recovery of heavy metal from SSPS, which shows great potential for the actual application.

The article the authors' insight on the benefits of advances in laser technology on the development optical coatings. Topics include the creation of optical coatings by the Key Laboratory of Materials for High Power Laser group for laser systems, the study on the impact of temperature-field and electric-field (E-field) distribution on optical coatings' laser-induced damage threshold (LIDT), and the use of large-aperture Brewster angled polarizer coatings and mirror coatings for beam steering.

The nitrozation reaction of cyclohexane in one-step reaction to form ɛ-caprolactam has been studied using transition metal salt as catalysts in this work. The results indicated that the catalysts play an especially important role. This method is expected to be a novel way to synthesize other lactam by similar reaction. The possible mechanism was suggested.