The Fabrication And Properties Of G-CNTs/PAAm Hydrogel For Air Tritium Absorption

The maximum activity of artificial radionuclides realesed from nuclear facilities to the work place and the environment is tritium. Along with the development of nuclear power plant in our country, nuclear facilities have a growing impact on staffs working in the palce involving tritium. Recently, tritium individual protective equipments using at place involving tritium are imperfection in our cpuntry. This study is to introduce a new absorbent material for tritium protection fabricated by irradiation-induced grafting and crosslinking two-steps method combining excellent properties of carbon nanotubes and hydrogel. Then, the systemic research of physico-chemical properties and absorption property of these materials have been done.This paper characterized composite hydrogel through using many techniques.Fourier Transform Infrared spectroscopy(FTIR) and Transmission electron microscope(TEM) of CNTs(pristine carbon nanotubes) and G-CNTs(carbon nanotubes after grafted) intricate chains of acrylic acid have been successfully introduced into the surface of CNTs after irradiation induced grafting reaction, and G-CNTs has exellent dispersibility in water. In addition, X-ray diffraction(XRD)pattern of G-CNTs and CNTs show no large change in the crystal lattices of G-CNTs has been found after grafted. According to thermal gravimetric analysis(TGA) curves of CNTs and G-CNTs, grafting ratio of G-CNTs(15%) can be calculated. G-CNTs dispersed well in hydrogel fabricated through irradiation induced crosslinking. XRD and BET are used to analyze the sructure and surface area of hydrogels. Compared with PAAm hydrogel, two new peaks can be found in the XRD pattern of G-CNTs/PAAm hydrogel which are associated with CNTs. The surface area ofG-CNTs/PAAm hydrogel is more than two times as PAAm hydrogel.G-CNTs/PAAm hydrogel and PAAm hydrogel with the similar gel content were used in absorption experiments, respectively. The absorption experiment results of the two groups of hydrogel equal in quality in water show PAAm hydrogel turns saturated after 3000 minutes, the water absorption(WA) value of PAAm hydrogel can reach to7000% finally. While the WA of G-CNTs/PAAm hydrogel shows the same trend, but it turns saturated after 1000 minutes which is less than 2000%. In the vaporous absorption experiments of hydrogels, PAAm hydrogel and G-CNTs/PAAm hydrogel lost absorption performance after 40 minutes and 100 minutes, respectively. The results demonstrate that G-CNTs dispersed well in hydrogel where surface area and mechanical property of hydrogel have been improved. Due to these two performances of G-CNTs/PAAm hydroge, better vaporous water absorption ability was shown compared with the PAAm hydrogel.The tritium absorption results show G-CNTs/PAAm hydrogel posses more excellent absorption performance than PAAm hydrogel. Tritium absorption efficiency of G-CNTs/PAAm hydrogel has been higher than 90% before 300 minutes.While tritium absorption efficiency of PAAm hydrogel decreased to 90% after 255 minutes.