Preparation Of Konjac Base Novel Adsorption Materials And Its Adsorption Performance Of Cesium

The rapid development of nuclear power technology has solved the problem of some energy shortages,but at the same time it has also produced a large amount of radioactive waste.If it is improperly handled,it will endanger the surrounding or even the global environment.In the Fukushima nuclear leak accident,a large amount of radioactive wastewater containing Cs⁺was discharged into seawater.Since¹³⁷Cs have a long half-life and it can enter the organism through the food chain,endangering human survival and health,the treatment and disposal of radioactive waste water containing cesium is very necessary.The adsorption method is most suitable for handling a large number of low-concentration nuclear waste liquid raw materials due to its flexible operation and low cost.The key to this method is to prepare materials that take into account both cost and adsorption efficiency.Konjac glucomannan?KGM?,a environment-friendly material was modified to prepare three kinds of adsorption materials in this study,nickel ferrocyanide/carboxymethyl konjac glucomannan composite gel particles?KNi FC/CKGM?,carboxymethyl konjac glucomannan-nickel ferrocyanide composite gel particles?CKGM-KNi FC?and Polyvinyl alcohol/carboxymethyl konjac-nickelferrocyanideinterpenetratingnetworkgelparticles?PVA/CKGM-KNi FC?.The adsorption properties of these three materials for Cs⁺were discussed in detail.The specific research results are as follows:1.The KNi FC/CKGM spherical adsorbent was synthesized by the sol-gel method via composite with KNi FC and CKGM.And this adsorbent was used to remove Cs⁺in wastewater.The adsorption mechanism was analyzed by means of FTIR,SEM,EDX,XPS and XRD.The optimization of the preparation conditions includes:?1?the effect of the mass ratio of the two components on the adsorption of Cs⁺;?2?the effect of the mass concentration of the CKGM solution on the balling and compressive strength;?3?the mass concentration of Al³⁺on the adsorbed Cs⁺and impact of compressive strength.Taking into account the ball formation,compressive strength and adsorption effect,the optimal conditions for preparation are as follows:the mass ratio of CKGM:KNi FC is 2:1,and the mass concentration of Al³⁺and CKGM are both 3%.The results of static adsorption experiments show that when the temperature is 298.15 K,the p H is 5,the amount of adsorbent material is 1 g·L^-1,the initial concentration is 20 mg·L^-1,and the contact time is 18 h,the adsorption material is Cs⁺.The removal efficiency of the adsorbent material can reach 94.8%.Through data fitting and calculation,it was found that the adsorption process of the adsorbed material on Cs⁺accorded with pseudo-second orderkinetics?R²=0.999?andFreundlichisothermadsorptionmodel?R²=0.985?.In the range of 288.15³28.15 K,the adsorption amount of Cs⁺by KNi FC/CKGM is positively correlated with temperature,and the adsorption process is a spontaneous and endothermic process.The results of dynamic adsorption experiments show that the breakthrough point and the depletion point decrease with the increase of the concentration and flow rate,and delay with the increase of the column height.2.The CKGM-KNi FC gel particle adsorbent was prepared by in-situ growth method using bimetallic(Al³⁺,Ni²⁺)cross-linked CKGM and Ni²⁺as the active site.The effects of p H value,contact time,initial concentration of Cs⁺,temperature and other factors on the adsorption performance of CKGM-KNi FC were studied.The experimental results show that when the p H is 6,the amount of adsorbent material is 0.4 g·L^-1,the reaction temperature is 298.15 K,the initial concentration is 20 mg·L^-1,and the contact time is 600 min,the utilization rate of the adsorbent is the highest,and the maximum adsorption capacity is 82.94mg·g^-1.The isothermal model and the kinetic model were fitted,through calculation and analysis of the experimental data,it was found that the adsorption process was more in accordance with the Freundlich model and the pseudo-second-order kinetics model.From the thermodynamic data obtained,the adsorption of Cs⁺by CKGM-KNi FC is a spontaneous endothermic process.Characterization methods such as FT-IR,XRD,and XPS effectively demonstrate that KNi FC can be firmly attached to the CKGM polymer skeleton.3.The PVA/CKGM-KNi FC interpenetrat network gel adsorbent was prepared by the sol-gel method via electrostatic spraying device after blending the sol solution of PVA and CKGM.The properties of the adsorbent for Cs⁺were also studied from these aspects of p H value,adsorption time,initial concentration of Cs⁺,and temperature.The experimental results show that when the p H is 5,the adsorbent dosage is 0.4 g·L^-1,the reaction temperature is 298.15K,the initial concentration is 20 mg·L^-1,and the adsorption time is 800 min,The maximum adsorption capacity of the adsorbent is 67.18 g·L^-11 The adsorption of the PVA/CKGM-KNi FC to Cs⁺in sea water shows that the material has good adsorption capacity in a variety of complex systems,and its salt tolerance is good.has good salt tolerance.The isothermal model,kinetic model and thermodynamics were studied and found that the adsorption process is more consistent with the Freundlich model and the pseudo-second-order kinetics model.From the thermodynamic data obtained,we can see,the adsorption of the PVA/CKGM-KNi FC to Cs⁺is a spontaneous endothermic process.Through FT-IR,XRD,EDX and other means,it has been proved that KNi FC is successfully loaded into the PVA/CKGM interpenetrating network.