CAJ | 학술논문

采用基于密度泛函理论的第一性原理研究了有水与无水环境下放射性核素 U在针铁矿（010）表面的吸附。结果表明，由于水分子与（010）表面的初始构型不同，其吸附能为-0.56～-0.85 eV。同时发现在缺水的情况下，U原子可吸附在针铁矿（010）表面的替代位（T ）、八面体间隙位（O ）及两个O原子的桥位（B）上。其吸附能为负，大小按吸附 T、B、O的顺序依次增大。水对 U 原子吸附能的影响较明显。当U原子占据替代位和八面体间隙位时，在其附近的水分子可增强 U原子在针铁矿（010）表面的吸附，可使U原子在针铁矿（010）表面的吸附能降低1～2 eV ；当U原子在桥位时，水分子既可增强也可减弱U原子在针铁矿（010）表面的吸附能力，这依赖于 U原子与水分子作用后其价态的变化。所有这些吸附均为放热反应。计算结果显示，由于水分子与U原子的吸附引起的表面晶格畸变较小，所有涉及的表面键长变化均不大于0.055 nm。所有涉及到的反应过程中均有 H、U、Fe原子上的部分电子转移到O原子上。
채용기우밀도범함이론적제일성원리연구료유수여무수배경하방사성핵소 U재침철광（010）표면적흡부。결과표명，유우수분자여（010）표면적초시구형불동，기흡부능위-0.56～-0.85 eV。동시발현재결수적정황하，U원자가흡부재침철광（010）표면적체대위（T ）、팔면체간극위（O ）급량개O원자적교위（B）상。기흡부능위부，대소안흡부 T、B、O적순서의차증대。수대 U 원자흡부능적영향교명현。당U원자점거체대위화팔면체간극위시，재기부근적수분자가증강 U원자재침철광（010）표면적흡부，가사U원자재침철광（010）표면적흡부능강저1～2 eV ；당U원자재교위시，수분자기가증강야가감약U원자재침철광（010）표면적흡부능력，저의뢰우 U원자여수분자작용후기개태적변화。소유저사흡부균위방열반응。계산결과현시，유우수분자여U원자적흡부인기적표면정격기변교소，소유섭급적표면건장변화균불대우0.055 nm。소유섭급도적반응과정중균유 H、U、Fe원자상적부분전자전이도O원자상。
In the absence and presence of water ,the absorption properties of uranium on the (010) surface of goethite (α-FeOOH ) were studied by first principle .It is found that the adsorption energy of a water molecular on the (010) surface is at the range from-0.56 eV to -0.85 eV ,depending on their initial configurations on the surface .It is also found that in the absence of water , uranium atom might be adsorbed into an octahedral site ,or a substitution site ,or a bonding bridge site between two oxygen atoms of the (010) surface of goethite .In the presence of water ,the water molecular might enhance the absorption ability of uranium atom on the (010) surface of goethite w hen uranium atom occupies the substitution site and octahedral site .In this case ,the adsorption energy of uranium atom on the surface may be reduced by 1-2 eV by water molecular .When uranium atom occupies the bridge site between two oxygen atoms on the surface ,the water molecular may either enhance or weaken the adsorption ability of an uranium atom on the (010) surface ,and it depends on the initial configuration of water molecular on the surface .But ,no matter how ,these adsorption processes of water and uranium on the (010) surface of goethite all belong to exothermic reaction . The lattice distortion induced by a uranium atom adsorption on substitution site , octahedral site , and bridge site between two oxygen atoms of the (010 ) surface of goethite or by a water molecular adsorption on the surface is found to be small ,and all the bonding length changes concerned on the surface are less than 0.055 nm .All these cases result from the interaction between U , O , Fe , and H atoms , where partial electrons of the U ,Fe ,and H atoms transfer into the O atoms .