In this paper, magnetic nanospheres coated with polystyrene （Fe3O4@PS） were prepared for the removal of organochlorine pesticides from aqueous solutions. The obtained Fe3O4@PS was round shape with diameter of 55±11 nm. The VSM results illustrated that its higher saturated magnetization was 36.76 emu g^-1 and it could be easily separated from aqueous solutions with a permanent magnet. The adsorption results showed that pesticides could be effectively adsorbed and the adsorption equilibrium time was less than 20 mins. The pseudo-second-order model was suitable to describe the adsorption kinetics. Compared with the Freundlich adsorption model, the adsorption data fitted well with Langmuir model. The effect of salinity and humic acid was also studied and the results illustrated that they could be neglected under optimized conditions. The asobtained sorbent showed a good performance with more than 93.3% pesticides removal in treating actual water samples.
The concentrations of polybrominated diphenyl ethers(PBDEs)were determined in the surface sediments of 20 locations in the East China Sea(ECS).The P PBDEs(sum of 13 PBDE congeners,without brominated diphenyl ether 209(BDE209)ranged from 2.6 to 49 pg g-1(dry weight)with an average of 21 pg g-1,which fell at the low end of the global range.The spatial distribution presented an offshore decreasing trend towards the outer shelf and along the coastline,suggesting a direct influence of the inputs by the Yangtze River.The P PBDE concentrations were influenced by the total organic carbon of the sediment,as demonstrated by their similar spatial distributions.The P C27?C29?C31n-alkanes concentrations and sand%reported in the literature for sediments in the ECS presented similar spatial distributions as P PBDEs,which suggests that a considerable part of P PBDEs may come from the Yangtze River and that grain size plays an important role in PBDE accumulation.The three dominant congeners were BDE28(19.8%),BDE47(26.4%),and BDE99(16.8%).The present study compared the congener patterns of the sedimentary PBDEs with those of commercial products.The results indicated the possible use of penta-BDE in the Yangtze River Basin in a wide range or the fractionation and transformation of PBDE congeners during their long-range transport.
