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TCE dechlorination rates, pathways, and efficiency of nanoscale iron particles with different properties

机译：TCE的不同性质的纳米铁颗粒的TCE脱氯速率，途径和效率

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Nanoscale Fe-0 particles are a promising technology for in situ remediation of trichloroethene (TCE) plumes and TCEDNAPLsource areas, but the physical and chemical properties controlling their reactivity are not yet understood. Here, the TCE reaction rates, pathways, and efficiency of two nanoscale Fe-0 particles are measured in batch reactors: particles synthesized from sodium borohydricle reduction of ferrous iron (Fe/B) and commercially available particles (RNIP). Reactivity was determined under iron-limited (high [TCED and excess iron (low [TCED conditions and with and without added H-2. Particle efficiency, defined as the fraction of the Fe-0 in the particles that is used to dechlorinate TCE, was determined under iron-limited conditions. Both particles had a core/shell structure and similar specific surface areas (similar to30 m(2)/g). Using excess iron, Fe/B transformed TCE into ethane (80%) and C3-C6 coupling products (20%). The measured surface area normalized pseudo-firstorder rate constant for Fe/B (1.4 x 10(-2) L(.)h(-1.)m(-2)) is similar to4-fold higher than for RNIP (3.1 X 10(-3) L(.)h(-1.)m(-2)). All the Fe-0 in Fe/B was accessible for TICE dechlorination, and 92 0.7% of the FeO was used to reduce TCE. For Fe/B, H2 evolved from reduction of water (H+) was subsequently used for TCE dechlorination, and adding H2 to the reactor increased both the dechlorination rate and the mass of TICE reduced, inclicatingthata catalytic pathway exists. RNIP yielded unsaturated products (acetylene and ethene). Nearly half (46%) of the Fe-0 in RNIP was unavailable for TCE dechlorination over the course of the experiment and remained in the particles. Adding H2 did not change the reaction rate or efficiency of RNIP. Despite this, the mass of TCE dechlorinated per mass of Fe-0 added was similar for both particles due to the less saturated products formed from RNIP. The oxide shell composition and the boron content are the most likely causes for the differences between the particle types.
机译：纳米级的Fe-0颗粒是用于三氯乙烯（TCE）羽流和TCEDNAPLsource区域的原位修复的有前途的技术，但是控制它们的反应性的物理和化学性质尚不清楚。在这里，在分批反应器中测量了两个纳米级Fe-0颗粒的TCE反应速率，途径和效率：由硼氢化钠还原亚铁离子合成的颗粒（Fe / B）和市售颗粒（RNIP）。在铁受限的条件下（高[TCED和过量的铁（低[TCED]条件下，添加和不添加H-2的情况下。））确定反应性。颗粒效率定义为颗粒中Fe-0用来对TCE进行脱氯的分数，在铁受限的条件下测定。两种颗粒均具有核/壳结构和相似的比表面积（类似于30 m（2）/ g）。使用过量的铁，Fe / B将TCE转化为乙烷（80％）和C3- C6耦合产物（20％）。Fe / B（1.4 x 10（-2）L（。）h（-1。）m（-2）的表面积标准化归一化伪一级速率常数类似于4-比RNIP高出三倍（3.1 X 10（-3）L（.hh（-1。）m（-2））。Fe / B中的所有Fe-0均可用于TICE脱氯，而92％的Fe-0用FeO还原三氯乙烯（TCE），对于Fe / B，水（H +）还原生成的H2随后用于三氯乙烯（TCE）脱氯，向反应器中添加H2既增加了脱氯速率，又降低了TICE的质量，增加了催化作用存在。 RNIP产生不饱和产物（乙炔和乙烯）。在整个实验过程中，RNIP中的Fe-0中几乎有一半（46％）无法用于TCE脱氯，并保留在颗粒中。加入H 2不会改变RNIP的反应速率或效率。尽管如此，由于RNIP形成的饱和产物较少，两个颗粒中每添加Fe-0的TCE脱氯质量相似。氧化物壳的成分和硼含量是造成颗粒类型之间差异的最可能原因。

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