Separation and Determination of Autocatalyst-Derived Platinum, Palladium, and Rhodium in the Environment

由于装有三效（即同时去除废气中的一氧化碳、氮氧化物和碳氢化合物）催化剂的汽车在400-1000℃的严格条件下运行，催化降解释放出铂、钯、铑，造成环境污染。然后，首先调查了4种汽油动力汽车排气管和消声器中烟灰中这些贵金属的排放量，确定其值分别为Pt: 11-32 ppm， Pd: 7-19 ppm和Rh: 3-25 ppm。这些贵金属的含量随着汽车在道路上行驶距离（5 -13万公里）的增加，以及排气管中的三元催化转化器的吸入而增加。在烟灰样品中，M IRA （DAIHATSU）检测到Pd和Rh， FAMILIA （MAZDA）、SUNNY （NISSAN）和SKYLINE （NISSAN）分别检测到Pt和Rh。SKYLINE（运行距离：13万km， 1992型）主要检出Na、Ca、Fe、Zn>Al>Si>Mg、Mn、Ni>Ce>V、Zr等，Ba、Co、La、Mo均在检出限之内。在涉及汽车烟尘和粉尘的环境样品中，主要道路（国道、8号线、Imamaehi、金泽）的土壤和苔藓（Bryum argenteum Hedw.）中，Pd （29-59 ppb）和Rh （15-34 ppb）在距离汽车道路白线边缘1m范围内检测到，Pt低于检测限（<8ppb）。这一结果表明，这些由机动车排放的贵金属颗粒相对较重，并且不会远离汽车排气管，在道路边缘脱落。在隧道道路（国道、157线、东二口、Kuwajima、石川县Tedori坝附近）中，距离内墙土壤和煤烟1 m范围内检测到Pd （26 ~ 84 ppb）、Rh (230 ~ 1700 ppb)， Pt低于检测限值（8 ppb）。在0.1 M盐酸中，Pd和Rh在排气管和消声器烟尘中的溶解度<1%，而Pt的溶解度未见明显变化。这一结果表明，少量的Pd和Rh以氯化物形式存在。少

Since automobiles equipped with three-way (i.e. removing carbon monoxide, nitrogen oxides, and hydrocarbons together in exhaust gasses) catalysts run under strict conditions as 400-1000 ℃, platinum, palladium, and rhodium are released by catalytic degradation, causing an environmental pollution. Then, the emissions of these precious metals in soot from the exhaust pipes and mufflers of 4 types of gasoline powered cars, were investigated first and ascertained that the values were Pt : 11-32 ppm, Pd : 7-19 ppm, and Rh : 3-25 ppm, respectively. The content of these precious metals tends to increase with increasing the running distance (50,000-130,000 km) of cars in roads, and also with drawing to the three-way catalytic converter in exhaust pipes.In soot samples, Pd and Rh were detected in M IRA (DAIHATSU), while Pt and Rh were detected in FAMILIA (MAZDA), SUNNY (NISSAN), and SKYLINE (NISSAN), respectively. Inorganic ingredient (10.7-5,440 ppm) detected except for precious metals in soot … More of SKYLINE (running distance : 130,000km, 1992 type) were Na, Ca, Fe, Zn>Al>Si>Mg, Mn, Ni>Ce>V, Zr, etc, while Ba, Co, La, and Mo were under detection limit.In environmental samples involving soot of cars and dusts, as soil and moss (Bryum argenteum Hedw.) in major road ways (national road, the 8 line, Imamaehi, Kanazawa), Pd (29-59 ppb) and Rh (15-34 ppb) were detected within 1m from the edge of the white line of automobile road, while Pt were under detection limit (<8ppb). This results indicate that these precious metalt particles emitted from motor vehicles are relatively heavy, and don't travel far from car exhaust pipes, falling out at the edges of roadways. In road ways of tunnel (national road, the 157 line, Higashifutaguchi and Kuwajima, near Tedori dam, Ishikawa), Pd (26-84 ppb) and Rh (230-1,700 ppb) were detected within 1 m from soil and soot of the inside wall, while Pt was under detection limit (8 ppb).Solubility of Pd and Rh in soot from the exhaust pipe and mufflers using 0.1 M hydrochloric acid were <1%, while that of Pt was not observed. This result suggests that a small amount of Pd and Rh is in chloride species. Less