Excellent removal performance of 4,4'-biphenyldicarboxaldehyde m-phenylenediamine Schiff base magnetic polymer towards phenanthrene and 9-phenanthrol: Experimental, modeling and DFT calculations studies.

Phenanthrene (PTH) and 9-phenanthrol (9-PTH) exhibited severe health threats and ecological hazards, for this reason, exploring a high-efficient removing strategy for PTH and 9-PTH could be considered of great urgency. Herein the 4,4'-biphenyldicarboxaldehyde m-phenylenediamine Schiff base magnetic polymer (magnetic BIPH-PHEN) was successfully fabricated via Schiff base polycondensation reaction and the subsequently one-pot embedded method. The mutual aromatic nucleus of BIPH-PHEN polymer and PTH/9-PTH could form π-π interaction, thus improving the capture ability, the embedded Fe3O4 nanoparticles provided the possibility for rapid separation. The physical and chemical properties of the magnetic BIPH-PHEN were systematically characterized. The removal rate of magnetic BIPH-PHEN towards PTH and 9-PTH was 85.65 % and 98.52 %, respectively (PTH or 9-PTH: 8 mg/L; Adsorbent: 0.2 g/L). The DFT calculations including energy calculations and electrostatic potential distribution analyzed the different bonding modes and proposed the most possible bonding modes in the adsorbent/adsorbate system. Moreover, the LUMO and HOMO orbits combined with energy gaps analysis proved the existence and specific types of the π-π interaction. The monolayer adsorption occurred on the homogeneous magnetic BIPH-PHEN surface, simultaneously the chemisorption was dominant. This work not only proposed new sights on assembling magnetic Schiff base polymer for removing polycyclic aromatic hydrocarbons, but also provided a deeper understanding of intramolecular interactions.

[Ecological risk evaluation of heavy metals of the typical dredged mud in Shanghai].

In order to discuss the potential ecological risk of heavy metals of the typical dredged mud in Shanghai, the Hakanson potential ecological risks method was used to analyse and assess the potential ecological risks of heavy metals, including Hg, Cd, Cu, Pb, As,Cr and Zn in dredged mud from the following three areas-the dock apron of Huangpu River, the mouth of the Yangtze River and inland waterways. The results showed that the mean values of ecological risk index (Er(i)) of the seven heavy metals are 20.05, 17.49, 8.82, 5.71, 4.68, 1.74 and 1.13, respectively, all of which belonged to the low ecological risk; Cd (one location in inland waterways) and Hg (three locations in the mouth of the Yangtze River and one location in inland waterways) are the most hazardous elements, with the Er(i) > 40, which belonged to the medium ecological risk or the high ecological risk, and other elements belonged to the low ecological risk. From the results of ecological risk indices(ERI) of the heavy metals in Shanghai dredged mud, the risk of the heavy metals belonged to the low ecological risk. The ERI of inland waterways, the mouth of the Yangtze River and the dock apron of the Huangpu River were 81.4, 57.7 and 52.5, respectively, which all belong to the low ecological risk.