Tingting Liu works as assistant professor in Institute of Circular Economy, Beijing University of Technology. She has a multi-subject education background on both ecology and economics, and had worked in Agriculture and Agri-Food Canada for 2.5 years. She has published more than 15 papers in reputed journals such as Applied Energy, Environmental Science & Policy, Resources, Conservation and Recycling.
With the exacerbating resource shortage and environmental pollution, the Chinese government is paying more and more attention on the collecting and utilization of recyclable resources. The rational utilization of recyclable resources not only contributes to resource conservation, but also to the reduction of environmental pollution. The recyclable resources statistics provides effective data support for the promotion of municipal solid waste recycling and utilization, which is important for waste management and sustainable development. However, the research and practice concerning recyclable resources statistics are still at initial stage in China. The government has raised requirements for the construction of recyclable resources statistical system, especially in the big cities such like in Beijing. By investigating and analyzing the statistical status quo of Beijing’s recyclable resource production and collecting, we point out existing problems such as undefined statistical types, incomplete statistical scope, nonstandard statistical methods, low integration of statistical resources among different departments, absence of statistical supervision and difficulties in verifying the accuracy of some statistics. According to the explored problems, we put forward some countermeasures for establishing and improving statistical system, such as issuing recycling catalogue of waste, standardizing the statistical methods, innovating collecting tracking method, building a sharing mechanism for the data monitoring, establishing statistical supervision system and appraisal mechanism.
Cristina Aguirre has completed her pregrades studies in Chemistry Enginnering at the age of 23 years from National Polythecnic School. At the present time, she is the assistant professor of the Department Nuclear Science of National Polythecnic School.
Polyurethane foams wastes (WFP) are usually destined to landfills without any recovery. In order to contribute to dispose of new alternatives, a experimental design 3x2 was proposed to study the mechanical behavior of synthesized elastomers which were obtained from depolymerization of WFP. Depolymerization reaction of foams was carried out with sodium hydroxide ascatalyzer. The decomposing agent used was castor oil (CO) in mass ratio of 3:1 with respect to WFP. The decomposition product (DP) was characterized by viscosity analysis according to ASTM D2196 and hydroxyl groups analysis by FTIR according to ASTM E168 was carried out. Synthesis of the polyurethane elastomer was performed from DP, which was subjected to a reaction synthesis with diphenylmethane-4,4'- diisocyanate (MDI) and subsequent curing process in a heated mold at 90 ⁰C under pressure of 2500 psi. Finally, it was possible to determine the influence of reactants ratio (MDI to DP, in mass ratio of 1:2,2; 1:2,7 and 1:3,2) and curing time (15 and 50 min) in terms of fracture strength of the obtained elastomer, in accordance with ASTM standard D412-15ª. The decomposition product had a viscosity of 26000 cPs and the hydroxyl groups (OH) were observed by FTIR in a wavelength of 3380,17 cm-1. The OH plotted band had a peak area of 46 A. cm-1, which corresponds to the presence of a polyol. The measured mechanical properties were found to be strongly influenced by the mass ratio of MDI to DP. The relation which allowed the major tensile strength (13,4 MPa) on elastomer of polyurethane was 1:2,2 along with a curing time of 15 min.