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Zhuang X.,Tongji University | Zhuang X.,Shanghai Second Polytechnic University | He W.,Tongji University | Li G.,Tongji University | And 3 more authors.
Fresenius Environmental Bulletin | Year: 2015

To better understand the pyrolysis process of polarizing film and to supply theoretic guidance for operating condition optimization, the pyrolysis kinetics of polarizing film was analyzed under inert conditions. Experiments were conducted by a thermogravimetric analyzer with heating rates of 5 K/min, 10 K/min, 15 K/min and 20 K/min. Based on the TG-DTG curves, the thermal decomposition characteristics of polarizing film were analyzed. The apparent activation energy and reaction order were evaluated based on Starink approach and Avrami theory. In the range of conversion fraction investigated (20%-80%), the apparent activation energy of polarizing film pyrolysis initially decreased from 158.8 kJ/mol to 140.0 kJ/mol and then increased to 152.4 kJ/mol afterward. Based on the Avrami theory, the reaction order varied from 0.790 to 1.215 at the temperature range of 565 K-585 K, indicating that the pyrolysis of polarizing film is not first-order reaction during its major mass loss stage. © by PSP.

Yang Y.,Shanghai JiaoTong University | Fang W.,Shanghai JiaoTong University | Xue M.,Shanghai JiaoTong University | Xu Z.,Shanghai JiaoTong University | Huang C.,Shanghai Xin Jinqiao Environmental Protection Company
Journal of Material Cycles and Waste Management | Year: 2014

Recently, a typical semi-automatic recycling line is proved to be a feasible method for resource recovery of raw material of waste CRTs. However, there are no relevant studies about health risk assessment of the particles and heavy metals diffused from this physical recycling process for CRTs. In this study, TSP, PM10 and heavy metals (Cr, Ni, Cu, Zn, Cd and Pb) in the ambience of the workshop have been evaluated. The mean concentrations of TSP and PM10 in the workshop were 481.5 and 316.9 μg/m3, respectively. Meanwhile, it can be seen that Zn (8.1 and 7.9 μg/m3, respectively) was the most enriched metal in TSP and PM10, followed by Pb (3.2 and 3.0 μg/m3, respectively). Health risk assessment showed that the total hazard index was 3.29, exceeding the danger threshold. The health risk of different metals was Cr > Cd > Ni. In short, the research results show that mechanical–physical process for e-waste recycling do exist the pollutant mission. So the effective measures should be taken to reduce the harm of pollutants on the workers’ health. © 2014 Springer Japan

Yuan W.,Shanghai Second Polytechnic University | Meng W.,Shanghai Second Polytechnic University | Li J.,Tsinghua University | Zhang C.,Shanghai Second Polytechnic University | And 4 more authors.
Waste Management and Research | Year: 2015

This research focused on the application of the hydrothermal sulphidisation method to separate lead from scrap cathode ray tube funnel glass. Prior to hydrothermal treatment, the cathode ray tube funnel glass was pretreated by mechanical activation. Under hydrothermal conditions, hydroxyl ions (OH-) were generated through an ion exchange reaction between metal ions in mechanically activated funnel glass and water, to accelerate sulphur disproportionation; no additional alkaline compound was needed. Lead contained in funnel glass was converted to lead sulphide with high efficiency. Temperature had a significant effect on the sulphidisation rate of lead in funnel glass, which increased from 25% to 90% as the temperature increased from 100 °C to 300 °C. A sulphidisation rate of 100% was achieved at a duration of 8 h at 300 °C. This process of mechanical activation and hydrothermal sulphidisation is efficient and promising for the treatment of leaded glass. © International Solid Waste Association.

Yang Y.,Shanghai JiaoTong University | Xue M.,Shanghai JiaoTong University | Xu Z.,Shanghai JiaoTong University | Huang C.,Shanghai Xin Jinqiao Environmental Protection Company
Journal of Material Cycles and Waste Management | Year: 2013

The aim of the study was to determine the potential environmental contamination in a typical factory for recycling waste electrical and electronic equipment in Shanghai. Heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in the soil around the factory have been evaluated in this paper. Compared with the background value, the concentrations of six metals detected in all the samples were higher, which showed that toxic metals were released into soil around the factory. Compared with the Environmental Quality Standards for Soils, China grade III, all the six metals are under soil guidelines. The non-cancer risk in different directions from the factory was in the order of: the north > the west > the south > the east. For inhalation and ingestion, the non-cancer risk in the soil west of the factory was biggest. Nevertheless, the non-cancer risk in the soil north of the factory was the biggest for dermal contact. The trend of cancer risk was the west > the south > the north > the east. The non-cancer risk and the carcinogenic risk for Cr, Ni, and Cd were all below the limiting value. This study might provide a reference for the risk assessment involved in electronic waste management and recycling activities. © 2013 Springer Japan.

Zhuang X.,Shanghai Second Polytechnic University | Li Y.,Shanghai Xin Jinqiao Environmental Protection Company | Yang Y.,Shanghai Xin Jinqiao Environmental Protection Company | Hu B.,Shanghai Second Polytechnic University | Zhao Y.,Shanghai Second Polytechnic University
Chinese Journal of Environmental Engineering | Year: 2016

With the increase of waste LCDs, indium recovery from waste LCD panels has aroused wide attention. In order to improve the indium recovery efficiency from waste LCDs, ultrasound was proposed to leach indium from waste LCDs in this study. With sulfuric acid as the leaching medium, influence of ultrasound and different factors on the indium leaching rate was investigated. Results show that the ultrasonic assistance can effectively improve indium leaching rate, and the leaching rate increases with the increase of ultrasonic power, reaction temperature and acid concentration, decreases with the particle size increasing. Under the optimized conditions i.e., ultrasound power of 800 W, reaction temperature of 60-70℃, sulfuric acid concentration of 0.5 mol/L, particle size smaller than 0.5 mm, 74.1% of indium was leached into the acid. Based on the results, reaction mechanism of ultrasonic assistance was further analyzed. According to the analysis, thermal and mechanical effect produced by sonochemical is the main reaction mechanism for the indium leaching reaction, which significantly improves the indium leaching rate. © 2016, Science Press. All right reserved.

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