Papers by Keyword: Rare Earth (RE)

Abstract: Hydrogen is a kind of clean energy, and application is limited because the efficiency of hydrogen production was not high before. This work in the paper was to study how to advance the hydrogen production efficiency by adding rare earths in the process of electrolysis of water. The result of tests proved that the efficiency of hydrogen production of water electrolysis electrode is dramatically improved when a few of REs are added in plating bath, and La cations are more effective than Ce cations when being added in the plating bath. Besides that, this article illustrated positive impact of RE on process of plating as well as effect of RE on composition of the plating and corrosion resistance of surface of the coating. Furthermore, argumentation extended to it that RE alone and compound of La and Ce have affected on efficiency of hydrogen production by water electrolysis process. Finally the paper showed that a new mechanism had been presented in a new angle being established in effect of RE on electron state of Ni plating.

Abstract: The reason why rare earth (RE) can play a role of strengthening catalytic degradation of wastewater has always been the topic of common interest for experimental and theoretical chemists. First it discussed the structural features and acts of RE elements, such as 4f orbitals whether to take part in bonding, their hybrid approach and the bonding ability of the hybrid orbitals. Then the paper took attention to how REs to reinforce catalysis for degradation of wastewater, including following aspects: REs' reinforcement on catalytic wet oxidation ability of wastewater, REs advancing H₂O₂ catalytic oxidation ability to deal with wastewater, REs improving TiO₂ photolysis efficiency of organics, and REs further improving role of O₃/TiO₂/UV photocatalytic degradation for wastewater. Finally there were the conclusion and prospect. Looking to the future, the quantitative understaning the 4f orbital of RE contribution still need to rely on the further development of quantum chemistry theory and method.

Abstract: The paper aims to explore influence of elements of transition metal (TM) and rare earth (RE) on iron-carbon micro-electrolysis for dyeing effluent degradation. There is evidence that there aren't many reports about it in domestic literature. The paper analysed the morphologies of surfaces of irons and activated carbons and designed the orthogonal experiments. Next was discussion for related influence factors. It deduced the mechanism that TMs and REs assist zero-valent iron (Fe⁰) catalysing degradation of dyeing effluent. It is based on following explanation. Cations of manganese and cobalt easily penetrate Fe⁰ lattices, but doesn't Ce⁴⁺ because of larger radius. Thus Ce⁴⁺ is weaker than Mn²⁺ and Co²⁺ for improving Fe⁰ activity. Furthermore, because the valence electron structure of Mn²⁺ is more stable than that of Co²⁺, Mn²⁺ is more efficient to assist Fe⁰ degrading dyeing effluent than Co²⁺. Therefore, the ranking of affecting Fe⁰ activity from greatest to smallest is Mn²⁺, Co²⁺ and Ce⁴⁺.

Abstract: Nowadays the traditional dyeing wastewater treatments based on flocculation-biochemical technology become more difficult than before. The study in this paper aim was it to probe how adding rare earths (REs) into iron-carbon micro-electrolysis process to advance dyeing wastewater degradation. Firstly, the principle was discussed. Then the experimental methods were stated and it followed by exploring effect of iron powder size on the dye decolorization rate. Next were design of the micro electrolysis orthogonal experiments and discussion of influences of related factors on waste water treatment. The experimental results show that besides common iron powder particle size and the processing time, the factors that have great influence on dyeing wastewater treatment are Ce⁴⁺, pH, La³⁺ and iron/carbon ratio. The sequence of factors influence on wastewater micro-electrolysis treatment is Ce⁴⁺ > pH > La³⁺ > iron/carbon ratio. When pH is 6, COD removal rate arrives at maximum 89%, however when the pH is in the case of too high or too low, the effect of sewage degradation is not good.

Abstract: The principle and methodology of effluent treatment by iron-carbon micro electrolysis were introduced in the paper. Then design of the orthogonal experiments for dyeing effluent treatment was formulated. Discussion of influences of related factors on effluent treatment followed. Results were got after the detailed analysis. Therefore, we deduced the mechanism that the cations of Transition Metal (TM) and rare earth (RE) assist of zero-valent irons catalyzing degradation of dyeing effluent. The mechanism is formed based on the following explanation. Cations of manganese and cobalt easily penetrate Fe⁰ lattices, while Ce⁴⁺ cations do it difficultly because of their larger radius. Thus Ce⁴⁺ is weaker than both of Mn²⁺ and Co²⁺ for helping zero-valent irons to improve their activity. Furthermore, because the valence electron structure of Mn²⁺ is more stable than that of Co²⁺, Mn²⁺ is better for assisting zero-valent iron catalysis of degradation of dyeing effluent than Co²⁺. Therefore, ranking of influence for zero-valent iron catalysis activity from greatest to smallest is Mn²⁺, Co²⁺ and Ce⁴⁺.

Abstract: In the paper we first discussed the principle of wastewater treatment by iron-carbon micro electrolysis. And the experimental methods were stated clear soon afterwards. Then we designed the micro electrolysis orthogonal experiments. Discussion of influences of related factors on waste water treatment followed. The main factors are cerium ion additive quantity, ratio of La³⁺/Ce⁴⁺ and pH in wastewater. The experimental results show that 1) The sequence of factors influence on wastewater micro-electrolysis treatment is Ce⁴⁺ > pH > La³⁺ > iron/carbon ratio; 2) The lanthanum and cerium ions have a synergistic effect in the wastewater treatment, and cerium ion plays a main role; 3) When pH is 6, COD removal rate arrives at maximum 89%, however when the pH is in the case of too high or too low, the effect of sewage treatment is not good.

Abstract: The effect of RE on modifying inclusions of 10PCu weathering steel was studied by metallographic examination, SEM and electron spectroscopy. Thermodynamic calculation was used to analyze the formation of RE inclusions in 10PCu weathering steel. The result shows that aluminosilicate inclusions are modified to round RE complex inclusions after adding RE to 10PCuRE steel.

Abstract: The effects of rare earth metals on the inclusions and the mechanical properties of 21Cr11Ni austenitic steel were studied by scanning electron microscope (SEM) and energy spectrum analysis. The results show that the morphologies and sizes of inclusions in 21Cr11Ni stainless steel are changed, and rare earth played a very good role of modifying inclusions. The fracture mode of 21Cr11Ni stainless steel is typical cleavage fracture, but quasi-cleavage and dimple fracture after adding RE into the steel. The transverse impact toughness of 21Cr11Ni stainless steel is improved obviously by RE. In comparison with 21Cr11Ni stainless steel without RE, the transverse impact toughness of 21Cr11Ni stainless steel with RE is increased 25.33% at-40°C, and the room temperature strength are improved, the elongation and reduction of area have been improved 9.18%, 12.71% respectively.

Abstract: The effect of Ce on structure and mechanical properties of 21Cr11Ni austenitic stainless steels were studied by metallographic examination, scanning electron microscope (SEM), tensile test. The results show that the proper amount of Ce can refine microstructure of austenitic stainless steel. Fracture is changed from cleavage to ductile fracture by adding Ce to austenitic stainless steel. 21Cr11Ni stainless steel containing 0.05% Ce can improve its high temerature strength, and the strength is increased 21.81% at 1073K respectively comparing with that of 21Cr11Ni stainless steel without Ce.

Abstract: The effect of RE on modifying inclusions of H13 die steel was studied by metallographic examination, SEM and electron spectroscopy. Thermodynamic calculation was used to analyze the formation of RE inclusions in H13 die steel. The result shows that sulfide inclusions are modified to round RE complex inclusions after adding RE to H13 die steel.