Transport of Lactate-Modified Nanoscale Iron Particles in Sand Columns

摘要

Nanoscale iron particles have great potential for in-situ remediation of subsurface soils.The transport of reactive nanoscale iron particles (RNIPs) into the contaminated subsurface is essential for the success of this remediation technology. RNIP cannot be transported through porous media effectively without surface modification. In this study, the transport of RNIP modified with lactate was investigated in 1-D sand column experiments under pressurized conditions using a natural sandy soil and an electrolyte solution. Sodium lactate and aluminum lactate were considered as lactate species for modification of RNIP. Aluminum lactate was mixed with bare RNIP at concentrations of 2, 4, 6, 8, 10 and 12%, and introduced at the top of the sand column. The elulion of RNIP from the sand column increased with increasing concentration of aluminum lactate up to 10% using a constant air pressure of 30 psig. Elution of RNIP slug through the sand column ranged from 55% for bare RNIP to 90% for RNIP modified with 10% aluminum lactate using an RNIP dosage of 4.8 g/L. Using a constant aluminum lactale concentration of 10%, the elution of RNIP through the sand column decreased with increasing dosage of RNIP, ranging from 90% for 4.8 g/L to 65% for 12 g/L. Using a dosage of 4.8 g/L of RNIP, 10% sodium lactate performed worse than 10% aluminum lactate, resulting in an elution value of 80% versus 90%, respectively.