Adsorption Properties Of Co²⁺、Ce⁴⁺ In Nuclear Power Plant Wastewater By Urea-Formaldehyde Resin And Its Modified Resin

With the rapid development of nuclear plant, it produces a large amount of radioactive wastewater. The wastewater with higher content of Co and Ce, which is mainly low-level radioactive wastewater, brings great pressure to the environment. The half-life period of 58Co is 71.3d, while the half-life period of 60Co is 5.271 years. Both of them will release β rays and y rays in the process of decay, and they are harmful to humans. The half-life period of 144Ce is 284.91d and regarded as a radioactive isotope which contributed to effective dose equivalent greatly. It’s necessary to remove Co and Ce from radioactive wastewater.In this paper, the synthetic method of Urea-Formaldehyde (UF) resin has been studied. Additionally, UF resin is modified with melamine to obtain Melamine -Urea-Formaldehyde (MUF) resin. Their structures and characteristics are identified by Laser Particle Size Scanner, SEM and FT-IR. The results show that both UF and MUF resin have abundant of active groups, such as -NH2,-OH that can coordinate with metal ions. The melamine increases the content of-NH2 and the rigidity of resin. With smaller particle size, MUF resin has larger specific surface area than UF resin.It is also studied the adsorption properties of Co2+ and Ce4+ by UF and MUF resins in this paper. Here are the conclusions:MUF resin adsorbs Co2+ and Ce4+ better than UF resin. The adsorption of Co2+ and Ce4+ are well fitted pseudo second order model on UF and MUF resin. Langmuir equation can describe the adsorption process precisely. The adsorptions are spontaneous endothermic reactions. When UF and MUF resin react with Co2+ about 24 hours at 25℃, the adsorption capacity of Co2+ is 1.26mg/g and 1.61mg/g, respectively. At the same condition with Ce4+, the adsorption capacity of Ce4+ is 7.39mg/g and 18.22mg/g, respectively. UF and MUF resin can be regenerated with HCl solution as desorption agent, which adsorption effects of Co2+ and Ce4+ are nearly remained after 5 times recycle.With the large number of active groups, large specific surface area, and the advantages of low cost, UF and MUF resin can remove radionuclides as an adsorbent. It has broad application prospects.