Nuclear Emergency Wastewater Treatment With Prussian Blue/Carbon Nanotube Sponge Absorbing Material And Performance

The growing energy crisis has brought the rapid development of nuclear science andtechnology. But at the same time, environmental problems of nuclear industry are measuring theirexposure to everyone, which can seriously affect people’s health and living environment,particularly the nuclear emergency wastewater. The issue of developing nuclear emergencywastewater treatment technology has caught redoubled attention from various countries in theworld.At present, ion exchange is most widely used due to its conveniency and efficiency，and thusmaterial is the key of this method. Here in our work, a novel kind of spongiform adsorbent wassynthesized by template replication, using the abundant and cheap polyurethane foam as atemplate, phenolic resin and multi-walled carbon nanotubes as carbon sources. Then using theoptimum sponge as the base, decorated Fe-Fe(II), Ni-Fe(II) and Ni-Fe(Ⅲ) Prussian blue onto thecarbon nanotube sponge by in situ growth method. SEM, XRD, char yield and volume shrinkagecharacterization demonstrated that the carbon nanotube sponge was equipped with large holes andporous structure, and there was a large number of MWNTs uniformly deposited on the surface andinternal cavities. Different carbonization temperature had great influence on the growth ofprussian blue nanoparticles,400°C was proved to be the optimal carbonization. SEM and IRshowed that in the prussian-blue/carbon nanotube sponge adsorbent material, prussian bluenanoparticles were fastened on cell walls of carbon nanotube sponge, and the Ni-Fe(II) Prussianblue content of Ni-Fe(II) prussian blue/carbon nanotube sponge was tested to be4.63wt%byICP.The change of the adsorption rate of Ni-Fe(II) prussian blue/carbon nanotube sponge forCu2+with time, sorbent dose and the pH value was investigated. Results showed that compared tocarbon nanotube sponge, Ni-Fe(II) prussian blue/carbon nanotube sponge had both the adsorptionability and ion exchange of Cu2+, but mainly for ion exchange. The removal of Cu2+was found toincrease with the time and the adsorption equilibrium would reach in about4hours. In neutral andweakly acidic conditions, it had the tallest removal efficiency of Cu2+. Cu2+maximum adsorptioncapacity could be9.783mg/g under conditions of room temperature25°C, weakly acidic, time of4h and1g of sorbent dose. The Freundlich adsorption model could well represent the adsorptionof Cu2+by both carbon nanotube sponge and Ni-Fe(II) prussian blue/carbon nanotube sponge.Research on selectivity abitility of Ni-Fe(II) prussian blue/carbon nanotube sponge indifferent valence state of ions were studied in this paper. By reaction in Cs+solution, the ionexchange process was between K+in Ni-Fe (II) prussian blue/carbon nanotube and Cs+in solution; In ionic solution reacts with divalent and trivalent, the ion exchange was mainly through the targetion (Cr3+, Sr2+, Cu2+) with K+and Ni2+. Combined with ICP and Mossbauer, Ni-Fe(II) prussianblue/carbon nanotube sponge showed the highest selectivity for Cs+in mixed aqueous solution,and its adsorptive capacity of Cs+reached13.46mg/g. It was found that their selectivity activitiesin sequence are as following respectively: Cs+>Sr2+>Cr3+>Cu2+.