| In recent years, nuclear energy in industry, agriculture, medicine, environment, energy and other fields are widely used. The large quantity of radioactive nuclear waste was produced, that great harm to human health. Biomass carbon materials is a kind of environment-friendly renewable resources, has been widely applied in the preparation of various performance o f carbonaceous materials. This topic is prepare biomass carbon materials using renewable biomass bayberry tannins and starch as raw materials by hydrothermal process and high temperature heat treatment, and applied the biomass carbon materials to adsorb radionuclide strontium. In this paper, the research content and results are as follows.(1) The biomass carbon materials reduced graphene oxide(rGO), and reduced graphene oxide–bayberry tannin(rGO/BT) were successful prepared by hydrothermal process at weight ratios of graphene oxide(GO) to bayberry tannin(BT) what are 1:0?1:0.5?1:1?1:1.5. Using different analytical method for analyzing the biomass carbon material, and the results showed that BT was immobilized and embed amongst GO sheets form classic spongiform 3D material, and the surface contains a lot of oxygen containing functional groups(-COOH, C-OH) what can ion exchange with radionuclide. The specific surface area of rGO/BT and rGO are 75.12, 49.63, 38.02, 20.31 m2 g- 1, respectively. BT molecule embedded reduces the material specific surface area. The biomass carbon materials, rGO, rGO/BT 0.5, rGO/BT 1.0, and rGO/BT 1.5, were used as adsorbent for adsorption experiments of the simulated radionuclide strontium. Research results show that the solution p H is major influence on the adsorption performance. Under acid condition, material surface easy protonation, hinder the adsorption/ion exchange for Sr2+. The results of isothermal adsorption and the adsorption dynamics research suggesting that the Langmuir model and second-order dynamic behavior are fitter the adsorption of strontium. The linear correlation coefficients are 0.9934, 0.9902, 0.9959, and 0.9977 for Langmuir model, with maximum adsorption capacity of 40.62, 60.61, 67.98, 44.31 mg/g; 0.9995, 0.9999, 0.9998, and 0.9999 for second-order dynamic behavior.(2) The carbon precursor was preared by hydrothermal method, with starch of agricultural and sideline products as the raw material. After that heat treatment carbon ball precursor at high temperature(> 600°C) to obtain biomass carbon ball. To analyze the biomass carbon ball show that the all of carbon ball is spherical, and the size of the biomass carbon ball which was heat treatment at 800 °C almost unanimous. The specific surface area of C-B, C-700, C-800, and C-900 are 1.01, 2.32, 18.86, 23.35 m2 g-1, respectively. Specific surface area increases with temperature rise; the sample has higher graphitization degree more than 800 °C. Infrared spectra show that the carbon ball contains a certain amount of oxygen containing functional groups, which advantageous to the radioactive nuclide adsorption/ion exchange(-COOH, C-OH). The biomass carbon ball(C-700, C-800, C-900) and active carbon(C-B, C-Y) were used as adsorbent for adsorption experiments of the simulated radionuclide strontium. Research results show that the solution p H is major influence on the adsorption performance. Under acid condition, material surface easy protonation, hinder the adsorption/ion exchange for Sr2+. The results of isothermal adsorption and the adsorption dynamics research suggesting that the Langmuir model and second-order dynamic behavior are fitter the adsorption of strontium. The linear correlation coefficients are 0.9734, 0.9805, 0.9937, 0.9755, and 0.9660 for Langmuir model, with maximum adsorption capacity of 29.75, 16.71, 43.88, 53.69, 36.70 mg/g; 0.9995, 0.9995, 0.9994, 0.9998, 0.9992 for second-order dynamic behavior.Review research experimental data and theoretical analysis show that the biomass carbon materials for radionuclide strontium adsorption has good adsorption effect, to purify the radioactive waste water has great ap plication potential, and provide a new thought to broaden the agricultural arbutus tannins, starch utilization field. |
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