Pd-catalyzed TCE dechlorination in groundwater: Solute effects, biological control, and oxidative catalyst regeneration
Pd-catalyzed TCE dechlorination in groundwater: Solute effects, biological control, and oxidative catalyst regeneration
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DOI：
10.1021/es991416j
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发表时间：
2000-08-01
影响因子：
11.4
通讯作者：
Reinhard, M
中科院分区：
文献类型：
--
作者：
Lowry, GV;Reinhard, M
在模拟地下水和真实的地下水中考察了Pd-on-γ-Al 2 O3催化剂对三氯乙烯（TCE）的脱氯性能。低的初始TCE转化率用于提供对催化剂活性变化的最大灵敏度。使用0.5 g 1%（w/w）Pd-on-gamma-Al 2 O3和4.3 min的保留时间，在去离子水中保持TCE转化率> 24%达60天。通过用稀次氯酸钠溶液处理，可逆转缓慢的催化剂失活。高浓度H2 CO 3、HCO 3-、CO 32-、SO 42-和Cl-的存在对催化剂活性没有不利影响。当溶液pH从4.3增加到11时，TCE转化率增加30%。87 mg/L SO_（32）~-或0.4 mg/L HS ~-的存在导致催化剂快速失活，推测是由于化学吸附到活性中心所致。用稀次氯酸钠溶液对HS-和SO_（32-）失活的催化剂进行再生。在天然地下水中开发的硫酸盐还原菌用H-2进行了修正，使催化剂失活，但在用稀次氯酸钠溶液冲洗后恢复了活性。在使用天然地下水和定期（4-7天间隔）SD-min脉冲稀释次氯酸钠溶液的63天实验期间，TCE转化率保持稳定在20%至28%之间。
The performance of a Pd-on-gamma-Al2O3 catalyst for dechlorination of trichloroethylene (TCE) was evaluated in synthetic and real groundwater. Low initial TCE conversions were used to provide maximum sensitivity to changes in catalyst activity. TCE conversions of > 24% were maintained in DI water for 60 days using 0.5 g of 1% (w/w) Pd-on-gamma-Al2O3 and a retention time of 4.3 min. Slow catalyst deactivation was reversed by treatment with a dilute sodium hypochlorite solution. The presence of high concentrations of H2CO3, HCO3-, CO32-, SO42-, and Cl- did not adversely affect catalyst activity. TCE conversion increased 30% upon increasing the solution pH from 4.3 to 11. The presence of 87 mg/L SO32- or 0.4 mg/L HS- caused rapid catalyst deactivation,, presumably due to chemisorption to active sites. Dilute sodium hypochlorite solutions regenerated catalysts deactivated by HS- and SO32-. Sulfate-reducing bacteria that developed in natural groundwater amended with H-2 deactivated the catalyst, but activity was restored after flushing with a dilute sodium hypochlorite solution. TCE conversion remained stable between 20 and 28% during a 63-day experiment using natural groundwater and periodic (4-7-day intervals) SD-min pulses of a dilute sodium hypochlorite solution.