Black carbon (BC) is known as a strong sorbent for the sorption of planar hydrophobic organic compounds (HOCs), but there is very little information about the sorption of nonplanar HOCs on BC. In this study, the sorption of di-(2-ethyl-hexyl) phthalate (DEHP), one kind of nonplanar phthalate acid ester (PAE), by environmental BC collected from river sediments and pure BC (char-wood, char-stalk and soot-ash) was investigated. Strong and nonlinear sorption was observed for the sorption of DEHP on both pure BC and environmental BC with the Freundlich exponent ranging from 0.55 to 0.75 except for soot-ash, and the measured K(BC) (BC-water partition coefficient) of DEHP was about one order of magnitude higher than its organic carbon-water partition coefficient. There was a significant difference in sorption capacity among the environmental and pure BC. The presence of di-methyl phthalate (DMP) could significantly decrease the sorption of DEHP on BC, especially for environmental BC. In addition, the contribution of BC to the total sorption of DEHP on original river sediments was more than 50% when the equilibrium concentration of DEHP was less than 10 μg L(-1). This study indicated that ortho-substituted nonplanar PAEs could also be strongly sorbed by BC, and the difference in sorption among the BC samples revealed that it is important to take the source of BC into account when assessing its effects on the fate of HOCs in aquatic environment. 相似文献
Low-level liquid borate wastes have been immobilized with paraffin wax using a concentrate waste drying system (CWDS) in Korean nuclear power plants. The possibility for improving chemical durability of paraffin waste form was suggested in this study. A small amount of low density polyethylene (LDPE) was added to increase the leaching resistance of the existing paraffin waste form. The influence of LDPE on the leaching behavior of waste form was investigated by performing leaching test according to ANSI/ANS-16.1 procedure during 325 days. It was observed that the leaching of nuclides immobilized within paraffin waste form made a marked reduction although little content of LDPE was added to waste form. The acceptance criteria of paraffin waste form associated with leachability index (LI) and compressive strength after the leaching test were fully satisfied with the help of LDPE. 相似文献
Journal of Material Cycles and Waste Management - The recycling and treatment of plastic waste become an increasingly serious environmental degradation challenge. To promote the recycling of... 相似文献
Schemes to protect the geological environment and reclaim land are core requirements for an application for mining rights and complying with mining regulations. Mining enterprises must be supervised to ensure they fulfill their obligations. To guide oversight of such schemes and to provide references for their compilation and review, this study evaluates land reclamation schemes in mining areas using a multi-attribute group decision-making method. First, linguistic intuitionistic fuzzy numbers are used to describe the evaluation information. Considering the authority and preferences of experts, methods for determining expert weights in four cases are established. Max–min deviation then determines the attribute weights, and a method for linguistic intuitionistic fuzzy group decision-making is proposed. Finally, the practicability of this method is verified through a comparative analysis of land reclamation schemes for four mining areas in Sichuan Province, China. The results show the proposed method to give simple and effective evaluation, making it reasonably applicable to the compilation and review of land reclamation schemes.
A detailed investigation was conducted to understand the contamination characteristics of a selected set of potentially toxic metals in Shanghai. The amount of Pb, Zn, Cu, Cr, Cd and Ni were determined from 273 soil/dust samples collected within urban area. The results indicated that concentration of all metals except Ni in soils was significant, and metal pollution was even severer in roadside dust. A series of metal spatial distribution maps were created through geostatistical analysis, and the pollution hotspots tended to associate with city core area, major road junctions, and the regions close to industrial zones. In attempt of identifying the source of metals through geostatistical and multivariate statistical analyses, it was concluded as follows: Pb, Zn and Cu mainly originated from traffic contaminants; soil Ni was associated with natural concentration; Cd largely came from point-sourced industrial pollution; and Cr, Ni in dust were mainly related to atmospheric deposition. 相似文献