In order to know about the variation of PAHs, PCBs and OCPs of sludge in landfill, discover the factors influencing the contents of PAHs, PCBs, OCPs and provide the scientific basis for the agriculture reuse of aged-sludge, the variation of PAHs, PCBs, OCPs contents and influencing factors in sludge landfill were studied in this paper. PAHs concentration of different landfill periods rang from 6.645 to 10.008 mg·kg -1 and show an increasing tendency with the increase of landfill duration. PAHs are mainly composed of more than four benzene-based compounds, and less than three benzene rings compounds contents of PAHs are relatively low. PCBs concentrations rang from 15.655 to 25.569 μg·kg -1 and present a decreasing trend with the landfill time, which far less than the standard of 0.2 mg·kg -1 . PCBs at the beginning of the landfill are mainly composed of the 3-Cl and 5-Cl compounds. In the late of the landfill, 2-Cl compounds increase significantly. The range of OCPs concentration is 1.78~2.37 μg·kg -1 . The main factors affecting the PAHs, PCBs and OCPs contents are microbial degradation and transformation. Analysis of the pollutants sources indicate that PAHs in sludge are mainly derived from the waste water of refinery, coking plant, gasworks, smelt plant and pitch plant. Chemical industry, timber process and electricity industry are the main sources of PCBs and OCPs in sludge.
Aramid fiber III has been treated by plasma treatment on different atmosphere gas to enhance the adhesive force between Aramid fiber III and epoxy matrix. The results of contact angle and SEM indicate that the obvious corrosion appear in the surface of aramid fiber III after plasma treatment. The yarn pull-out method was used to evaluate the effect of surface modification. The contact angle of original aramid fiber III is 65.9 o , and after treated the contact angle is declined to 62.2 o . The evaluation results show the tensile strength and NOL ILSS of treated Aramid fiber III/epoxy composite increased by about 10%. In summary, the effect of plasma treatment is obvious and has potential industry application.
Substituting certain atoms in a metal-oxo cluster (MOC) can enrich its structure, properties, and applications, often involving the replacement of one metal polyhedron with another that exhibits a comparable coordination environment. Herein, we synthesized three clusters Fe14-SO4, Fe14-SeO4, and Fe15, with the crystal compositions of [Fe14(SO4)O6(tea)7Cl6](FeCl3OFeCl3)0.5·4(C2H3N)·18(H2O) (tea = deprotonated triethanolamine), [Fe14(SeO4)O6(tea)7Cl6](FeCl3OFeCl3)0.5·(C2H3N)·20(H2O), and [Fe15O6(tea)8Cl6](FeCl4)2·Cl·22(H2O), using similar solvothermal methods. All three clusters exhibit similar cage-like structures, with Fe14-XO4 (X = S or Se) differing by substituting a shell iron polyhedron with a nonmetallic XO42– tetrahedron. This substitution, facilitated by the weaker binding of the iron polyhedron in the cluster and its geometrical similarity to XO42–, leads to more diverse coordination modes and weaker antiferromagnetic interactions of iron ions in Fe14-XO4 compared to Fe15. Our study highlights the uncommon replacement of a metal polyhedron with a nonmetallic oxoanion and its effects on the structure and properties of MOCs.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)