Characterization of Metal Oxide-modified Walnut-shell Activated Carbon and Its Application for Phosphine Adsorption: Equilibrium, Regeneration, and Mechanism Studies

余琼粉^1,2，LI Ming¹，NING Ping²，易红宏^3,2，TANG Xiaolong^3,2

1. Solar Energy Research Institute, Yunnan Normal University2. Faculty of Environmental Science and Engineering, Kunming University of Science & Technology3. School of Energy and Environmental Engineering, University of Science and Technology Beijing

摘 要：We prepared a kind of metal oxide-modified walnut-shell activated carbon（MWAC） by KOH chemical activation method and used for PH₃ adsorption removal. Meanwhile, the PH₃ adsorption equilibrium was investigated experimentally and fitted by the Toth equation, and the isosteric heat of PH₃ adsorption was calculated by the Clausius-Clapeyron Equation. The exhausted MWAC was regenerated by water washing and air drying. Moreover, the properties of five different samples were characterized by N₂ adsorption isotherm, SEM/EDS, XPS, and FTIR. The results showed that the maximum PH₃ equilibrium adsorption capacity was 595.56 mg/g. The MWAC had an energetically heterogeneous surface due to values of isosteric heat of adsorption ranging from 43 to 90 kJ/mol. The regeneration method provided an effective way for both adsorption species recycling and exhausted carbon regeneration. The high removal efficiency and big equilibrium adsorption capacity for PH₃ adsorption on the MWAC were related to its large surface area and high oxidation activity in PH₃ adsorption-oxidation to H₃ PO₄ and P₂ O₅. Furthermore, a possible PH₃ adsorption mechanism was proposed.

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