Cuttlefish ink loaded polyamidoxime adsorbent with excellent photothermal conversion and antibacterial activity for highly efficient uranium capture from natural seawater.

Owing to the abundant uranium reserves in the oceans, the collection of uranium from seawater has aroused the widespread interest. Compared to the uranium extraction from ore, uranium collection from seawater is a more environmentally friendly strategy. The amidoxime (AO) functional group has been considered as one of the most efficient chelating groups for uranium capture. In this work, by drawing upon the photothermal character and antibacterial activity of cuttlefish ink, a cuttlefish ink loaded polyamidoxime (CI-PAO) membrane adsorbent is developed. Under one-sun illumination, the CI-PAO membrane shows a high extraction capacity of 488.76 mg-U/g-Ads in 500 mL 8 ppm uranium spiked simulated seawater, which is 1.24 times higher than PAO membrane. The adsorption rate of CI-PAO membrane is increased by 32.04%. Furthermore, exhibiting roughly 75% bacteriostatic rate in composite marine bacteria, the CI-PAO shows a dramatically antibacterial activity, which effectively prevents the functional sites on the adsorbent surface from being occupied by the biofouling blocks. After immersing in natural seawater for 4 weeks, light-irradiated CI-PAO gave high uranium uptake capacity of 6.17 mg-U/g-Ads. Hence, the CI-PAO membrane adsorbent can be considered as a potential candidate for the practical application for uranium extraction from seawater.

Occurrence and distribution of organochlorine pesticides (OCPs) in surface sediments of the Bohai Sea, China.

Fifty-five surface sediment samples covering virtually the entire Bohai Sea (Bohai) were analyzed for organochlorine pesticides (OCPs), in order to provide the extensive information of recent occurrence levels, distribution, possible sources and potential biological risk of these compounds in this area. Concentrations of total dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) in Bohai ranged widely from 0.24 to 5.67ngg(-1) (mean 1.36+/-0.93ngg(-1)) and 0.16 to 3.17ngg(-1) (mean 0.83+/-0.57ngg(-1)), respectively. High concentrations of DDTs were observed in the coastal areas especially at the isolated sites neighboring the harbor or port regions. The recent DDT inputs could be mainly attributed to the agricultural activity (e.g. dicofol), wastewater of chemical plants and the usage of antifouling paint. The distribution pattern of HCHs was different from that of DDTs due to their different physical-chemical properties and amounts of production and usage in the past. (DDE+DDD)/DDT ratios indicated that the degradation of the parent DDT occurred significantly. The contributions of previous and current inputs of pesticides in the coastal areas were distinguished by means of principal component analysis, suggesting that the recent usage of DDT and technical chlordane could serve as important fresh input sources for OCPs. DDTs and chlordanes are the two-main species of OCPs with more ecotoxicological concern in Bohai.

[Contaminative features of heavy metals for tidal sediment cores in Tianjin Bohai Bay].

Three sediment cores were collected in Nov. of 2003 from Dagu estuary to Qikou estuary. The grain size, TOC and heavy metal contents of core sediments were analyzed in order to study the geochemical characteristics, contamination features and the spatial and vertical distribution characters for heavy metals of tidal zones in Bohai Bay. The grain size of tidal sediments becomes finer from north to south. Ultrafine, fine and power sand are the main compositions in the sediment of Dagu and Duliujian estuary. The sediment of Qikou estuary is mainly composed by power and ultrafine sand. The vertical distribution trends of three sediment cores indicate that the grain-size becomes bigger from the bottom to the upper. The distribution of Fe, Al, Mn contents has distinct negative correlation with the grain-size of sediment, that is to say, the fine-grained sediments have higher contents of Fe, Al, Mn. Pb, Zn and Cd are the dominating contaminative elements in tidal sediments of Bohai Bay. Their contents are higher than the corresponding environmental background values, indicating of the anthropogenic enrichment.