"Tin-palladium supported on alumina as a highly active and selective catalyst for hydrogenation of nitrate in actual groundwater polluted with nitrate"
We developed Sn0.5Pd/Al2O3 showing high activity and high selectivity to gaseous products towards the hydrogenation of NO3- with H2 in aqueous NO3- solutions via precise control of the Sn/Pd molar ratio. For the catalyst with the optimum Sn/Pd molar ratio, the surface concentration of adsorbed nitrogen on the Pd sites is thought to be high and that of the adsorbed hydrogen on the Pd sites is thought to be low. This is due to the abundant supply of NO2- for the Pd sites and the prompt consumption of adsorbed H on the Pd sites for reduction of the oxidized Sn sites formed by the reduction of NO3-, respectively, leading to the high selectivity to gaseous products. Although the catalytic performance of Sn0.5Pd/Al2O3, like that of Cu0.5Pd/Al2O3, was lower in groundwater, the decrease for Sn0.5Pd/Al2O3 was less than that for Cu0.5Pd/Al2O3. Nitrate in the groundwater polluted with 0.4 mmol dm-3 (250 cm3) of NO3- was completely reduced at 298 K in 24 h with a selectivity for gaseous products of around 90% in the presence of 10 mg of Sn0.5Pd/Al2O3, whereas it took 60 h in the presence of Cu0.5Pd/Al2O3, and the selectivity for gaseous products was around 75%. However, both catalysts showed comparable high activity and high selectivity in aqueous NO3- solutions. When reactions were performed in aqueous NO3- solutions containing other anions (Cl-, SO42-, and SiOxn-) present in the groundwater, Cl- had the largest negative impact but it had a smaller impact in the presence of Sn0.5Pd/Al2O3 than it did in the presence of Cu0.5Pd/Al2O3. On the basis of adsorption isotherms for Cl- and kinetics analysis of the hydrogenation of NO3-, it was concluded that Sn0.5Pd/Al2O3 had less affinity for Cl- and a strong affinity for NO3- on the Sn sites, leading to its superior catalytic performance in groundwater.
"Determination of acid site location in dealuminated MCM-68 by Al-27 MQMAS NMR and FT-IR spectroscopy with probe molecules"
International Symposium focusing on Advancement and Prospect of Catalysis Science & Technology(Pre-symposium of ISHHC 18)（7月25日〜27日、シドニー）
（招待講演）大友 “Post-synthesis of highly active Hf-Beta zeolite assisted by NH4F: a new insight into the formation of active Lewis acid sites for MPV reduction”
Pre-conference of TOCAT8 and the 5th International Symposium of Institute for Catalysis（8月3日〜4日、札幌）
（口頭発表）金 “Adjacent acid-base pair sites on silica surface constructed by hydrolysis of pre-anchored amide fixed on silica”
TOCAT 8（8月5日〜9日、横浜）
（口頭発表）平山 “Catalytic reduction of nitrate in water toward purification of real groundwater”
（ポスター発表）金 “Adjacent acid-base pair sites on silica surface constructed by hydrolysis of pre-anchored amide”
ZMPC2018（8月5日〜9日、横浜）
（口頭発表）大友 “Determination of Acid Site Location in Dealuminated MCM-68 with 12-10-10-ring Structure by 27Al MQMAS NMR and FT-IR Spectroscopy with Probe Molecules”
