We examined an improved preparation method of recycled unsaturated polyester resin from recovered monomeric materials obtained from the depolymerization of fiber-reinforced plastics (FRPs). The formation of unsaturated polyester progressed smoothly in the presence of catalytic amounts of Ca(OAc)2 and Ti(OBu)4. The quality of the resin was estimated by the durometer hardness test. The strength test of FRP board prepared from recycled resin showed sufficient hardness for practical use (about 94% of the tensile strength of new resin). We examined the recycled resin by using it to mold successfully an actual test product. 相似文献
We recently developed a new isolation method for diesel exhaust particles (DEP), involving successive extraction with H2O, sodium bicarbonate, and sodium hydroxide, in which the sodium hydroxide extract was found to consist of phenolic components.
Analysis of the extract revealed that vasodilative-active nitrophenols are in DEP in significantly higher concentrations than
those estimated by an earlier method involving a combination of solvent extraction and repeated chromatography. These findings
indicated that our new procedure offers a simple, efficient, and reliable method for the isolation and identification of bioactive
substances in DEP. This encouraged us to extend our work toward investigating new vasodilatory substances in the sodium bicarbonate
extract. 相似文献
To develop a new method for the chemical recycling of plastics, we examined the formation of recycled polymers from the recovered
monomeric materials of solubilized waste fiber-reinforced plastics (FRP) under supercritical alcoholic conditions. Treatment
of waste FRP with supercritical MeOH resulted in the formation of monomeric organic compounds that mainly contained dimethyl
phthalate (DMP) and propylene glycol. The presence of these materials was confirmed by gas chromatography and nuclear magnetic
resonance analyses and they were mixed with new DMP and glycols in various ratios to form unsaturated polyesters. The polymerization
progressed successfully for all mixing ratios of the recovered and new DMP. Hardness tests on these recycled polymers indicated
that the polymer made from a 1:1 mixture of recovered and new dimethyl phthalate had almost the same level of hardness as
the polymers made from new materials. We also examined the formation of recycled FRP by using glass fibers and monomeric materials
recovered through the present depolymerization method.
Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6 相似文献
This pilot-scale study evaluated the use of intermediate cover soil barriers for removing heavy metals in leachate generated from test cells for co-disposed fly ash from municipal solid waste incinerators, ash melting plants, and shredder residue. Cover soil barriers were mixtures of Andisol (volcanic ash soil), waste iron powder, (grinder dust waste from iron foundries), and slag fragments. The cover soil barriers were installed in the test cells' bottom layer. Sorption/desorption is an important process in cover soil bottom barrier for removal of heavy metals in landfill leachate. Salt concentrations such as those of Na, K, and Ca in leachate were extremely high (often greater than 30 gL(-1)) because of high salt content in fly ash from ash melting plants. Concentrations of all heavy metals (nickel, manganese, copper, zinc, lead, and cadmium) in test cell leachates with a cover soil barrier were lower than those of the test cell without a cover soil barrier and were mostly below the discharge limit, probably because of dilution caused by the amount of leachate and heavy metal removal by the cover soil barrier. The cover soil barriers' heavy metal removal efficiency was calculated. About 50% of copper, nickel, and manganese were removed. About 20% of the zinc and boron were removed, but lead and cadmium were removed only slightly. Based on results of calculation of the Langelier saturation index and analyses of core samples, the reactivity of the cover soil barrier apparently decreases because of calcium carbonate precipitation on the cover soil barriers' surfaces. 相似文献
As the stabilization criteria for landfill sites, only chemical criteria for the leachate discharges from the landfill sites have been used in Japan and many other countries. Recently, chemical oxidation has been developed as a method for the early-stabilization of landfills. However, by-products that are difficult to detect by chemical analysis can be produced by this method. Therefore, toxicity tests are useful tools for detecting the changes of leachate quality after application of this method. The heat source in the A landfill was analyzed by organic position inquiry technology, and ozone-treated leachate was sprayed back to the heat source in the landfill. Toxicity changes of the leachate after the spray were monitored using Microtoxtrade mark, ToxScreen-II, and DaphTox tests. The hardly-degradable organic matter was efficiently removed and toxicities of the leachate in the heat source decreased after the application. These toxicity results were significantly related to chemical oxygen demand (COD) changes. Thus, it was concluded that the toxicity tests were effective for monitoring the leachate quality after applying the chemical oxidation method for landfill stabilization, and its incorporation to establish the criteria for early-stabilization of landfill sites needs to be considered. 相似文献
Polychlorinated dibenzo-p-dioxin, polychlorinated dibenzofuran and dioxin-like polychlorinated biphenyl concentrations in human blood, lung, liver, bile, pancreas, spleen, kidney and mesentery fat were determined to assess the concentrations and distribution of these chemicals in human tissues from 20 donors. The mean TEQ concentrations in blood, lung, liver, bile, spleen, pancreas, kidney and mesentery fat were 119, 178, 228, 50, 113, 163, 138 and 139 pg TEQ/g lipid, respectively. Parallel levels were seen in the blood, spleen, kidney and mesentery fat; in the lungs and pancreas, the levels were somewhat higher. Among the organ tissues samples, the highest concentration was observed in the liver and the lowest in the bile. Mean total-TEQ concentration of the liver was about 4.5 times higher than that of bile. Positive correlations were observed among the concentrations of dioxins in various tissues. However, the concentrations in bile were not correlated with any tissues. It is suggested that the distribution behavior of dioxin-like congeners in human tissues varies among tissues and the kinds of congeners ingested. To evaluate the relationship between the accumulation levels of dioxins and their pathophysiological significance or risk, data must be accumulated from a more extensive group of human samples. 相似文献
The first draft scenario toward net zero greenhouse gas (GHG) emissions by 2050 for the material cycles and waste management sector was presented by the Ministry of the Environment, Japan in August 2021. The details of the future GHG emission estimation used to create the draft scenario are described in this document. For multiple scenarios where more aggressive measures, such as carbon capture, utilization, and storage (CCUS), were included in addition to business-as-usual and the current policy continuity scenario, future GHG emissions were estimated as the sum of the products of activities and emission factors indicating changes in measures between scenarios. The estimation outcomes demonstrated that future GHG emissions from the solid waste management sector could be anticipated to be zero or even negative when material conversion to biomass, primarily for plastics, recycling to raw materials, and installation of CCUS at incineration facilities are assumed. Extensions of prior plans are not enough to reach the goal of net zero emissions, according to the measures necessary and the volume and pace of their implementation suggested in this study. Stakeholders should collaborate with great ambition.
Journal of Material Cycles and Waste Management - Japan has been promoting 3R (reduce, reuse, and recycle) policies for several decades, but the recycling rate of the whole country has leveled off,... 相似文献