DNA-loaded Magnetic Nanoparticles: Preparation And Removal Study Of Waste Water Pollutants

The class of pollutants that interact with DNA usually has a serious effect on human health due to the strong mutagenicity,carcinogenicity and teratogenicity.Therefore,the removal of such contaminants is important,particularly the DNA dye ethidium bromide?EtBr?and the antitumor drug doxorubicin?Dox?.In order to remove such contaminants from aqueous solutions quickly and efficiently,DNA was covalently anchored on the surface of magnetic nanoparticles for the removal because of the special effects among DNA and pollutants.The DNA was successfully anchored on the surface of Fe₃O₄ nanoparticles and the optimized synthetic conditions are as followes:DNA 250 mg,EDC 1.5 g,NHS 0.9 g,50°C,6 h of reaction time.The loading of DNA is approximately 60.5 mg·g^-1.Batch experiments were conducted to investigate the effect of removal of EtBr and Dox by DNA-Fe₃O₄,and the influence factors such as contact time,initial concentration,DNA-Fe₃O₄ dosage,pH,ion concentration,and temperature were investigated.The results showed that the adsorption of EtBr in aqueous solution by DNA-Fe₃O₄ can reach an equilibrium in 2 min;the most suitable operating condition for EtBr was pH 7,0 of ion concentration,4-35°C;at the same time,1.0 g·L^-1 DNA-Fe₃O₄ can be reused 3 times to adsorb 0.5 mg·L^-1 EtBr solution with removal efficiency still high as 99%.Dox's removal by DNA-Fe₃O₄ can reach an equilibrium within 20 minutes;the most suitable operating condition was pH 7,low ion concentration,35°C.Adjusting the amount of adsorbent can make removal efficiencies of EtBr and Dox with different initial concentrations reach 99%.The kinetics studies show that adsorptions of EtBr and Dox on DNA-Fe₃O₄ all obey the pseudo second-order kinetics adsorption model.And the adsorption isotherm studies show that the model for EtBr adsorption is Freundlich while Dox follows the Langmiur adsorption isotherm model at 25°C and 35°C.Based on results above,DNA-Fe₃O₄ nanoparticles can remove EtBr and Dox in aqueous with high removal efficiency,fast speed and simple separation process,which has a great potential for application of the treatment of.Meanshile,it also provides an opprtunity for the treatment of other DNA-bound pollutants.