Radioactive iodine present in nuclear waste water streams is harmful to human health and environment. Since iodine will exist in multiple states in water, accurate quantification of the total iodine content in any given sample is very difficult. The development of a method for determining the total iodine content accurately in water, and finding materials which can effectively remove the iodine are of particular importance. Here, a method was proposed for determining the concentration of iodine by cyclohexane extraction. And two kinds of zeolite imidazole skeleton materials ZIF-8 and ZIF-67 were prepared to be used as adsorbents to effectively adsorb iodine from an aqueous environment. Samples ZIF-8 and ZIF-67 were characterized by different methods. The results show that these two kinds of materials have good chemical structure and large specific surface area. The results of adsorption kinetics experiments show that the adsorption of ZIF-8 and ZIF-67 materials to iodine can reach the equilibrium within 60 min. The iodine adsorption behaviors of both materials are fitted with the pseudo second-order kinetic model. Their adsorption thermodynamics indicate linear adsorption behavior for iodine in the case of both zeolites. Adsorption capacities of ZIF-8 and ZIF-67 for iodine could reach as high as 2000 mg·g ^-1.

The synergy of plasma and catalytic materials for CO₂ methanation provides the possibility for CO₂ reuse. The preparation method of catalytic materials plays an important role on their structure and performance. In this work, Ru/γ-Al₂O₃-P and Ru/γ-Al₂O₃-T catalytic materials were prepared by atmospheric-pressure H₂ plasma reduction and H₂ thermal reduction, respectively, using Ru/γ-Al₂O₃ precursor prepared by incipient wetness impregnation. The catalytic activity of Ru/γ-Al₂O₃ prepared by different methods was evaluated during atmospheric-pressure plasma reduction for CO₂ methanation reaction. Different techniques were used to investigate the effect of preparation methods on the structure of Ru/γ-Al₂O₃, analyze the influences of structural factor on the catalytic activity of Ru/γ-Al₂O₃, and discuss the preparation mechanism of Ru/γ-Al₂O₃-P and Ru/γ-Al₂O₃-T. The results show that the CO₂ conversion of γ-Al₂O₃ support is 24.8% under the combination of atmospheric-pressure plasma, and the main product is CO. However, the main CO₂ catalytic product of Ru/γ-Al₂O₃ is methane under the combination of atmospheric-pressure plasma. CO₂ conversion over Ru/γ-Al₂O₃-P is 77.3%, which is higher than that over Ru/γ-Al₂O₃-T (69.9%). Higher catalytic activity of Ru/γ-Al₂O₃-P is ascribed to the higher metallic Ru ratio and Ru/Al atomic ratio, as well as the smaller and higher dispersion of Ru nanoparticles. This work proves that highly active supported metal catalytic materials can be prepared by atmospheric-pressure H₂ plasma.

The ammonia selective catalytic reduction (NH₃-SCR) technology is still necessary to further develop denitration catalytic materials which have good catalytic activity, high stability and environmental friendliness at relatively low temperature (<300 ℃). In this work, the Mn-Fe-O catalyst was prepared by oxalate co-precipitation method and modified with different contents of CeO₂ for low temperature NH₃-SCR of NO. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption, X-ray photoelectron spectroscopy (XPS), temperature programmed reduction or desorption (H₂-TPR, NH₃-TPD). The catalytic results show that as compared with pure Mn-Fe-O sample, Mn-Fe-O modified with suitable CeO₂ content shows much better performance for NH₃-SCR with 95% conversion of NO and a high N₂ selectivity at 80 ℃ under the same reaction conditions. CeO₂ modification increases the content of Fe ³⁺, Mn ³⁺ and Mn ⁴⁺, and the number of surface acid sites on the surface of Mn-Fe-O oxide, which contribute to the adsorption of NH₃ and the catalytic reaction. In addition, redox reactions among Fe ²⁺/Fe ³⁺, Mn ²⁺/Mn ³⁺/Mn ⁴⁺ and Ce ³⁺/Ce ⁴⁺ pairs improve the redox ability and stability of the catalyst.

Boron is an important micronutrient for plants, animals, and humans. However, high concentrations of boron are harmful to animals and plants. A magnesium-aluminum-cerium hydrotalcite (Mg-Al-Ce-HT) was successfully prepared by the co-precipitation method for boron removal. Different analyses were conducted to confirm the structure and characteristics of Mg-Al-Ce-HT. Adsorption efficiency of Mg-Al-Ce-HT was studied as a function of initial pH, amount of adsorbent, concentration of initial boric acid, and contact time. The pH of the solution had a negligible effect on boron sorption when pH was less than 8.0. However, the adsorption capacity decreased when the pH exceeded 8.0. The optimum amount of the adsorbent was 200 mg, and the maximum adsorption capacity was 32.52 mg·g ^-1. Boron removal reached equilibrium at 160 min. The thermodynamic parameters revealed that the adsorption was a non-spontaneous and endothermic process. The data fitted well with the Langmuir model, which indicated that the process involved monolayer adsorption.