Injection of nanoscale Fe 3O 4 slurry coupled with the electrokinetic process for remediation of NO 3 − in saturated soil: Remediation performance and reaction behavior

• Published in: Separation and purification technology Vol. 79; no. 2; pp. 272 - 277
• Main Authors: Yang, Gordon C.C., Wu, Min-Yen
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2011
• Subjects: Adsorptive reduction; Electrokinetic process; Nanoscale Fe 3O 4; Nitrate; Nitrate; Electrokinetic process; Adsorptive reduction; Nanoscale Fe 3O 4
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2011.02.005

► Injecting nano-Fe 3O 4 into the anode reservoir and EK is able to degrade nitrates. ► The relevant reaction behavior confirms the proposed adsorptive reduction model. This work aimed to investigate the remediation performance and reaction behavior of the injection of nanoscale Fe 3O 4 slurry coupled with the electrokinetic (EK) process for remediation of NO 3 − in a saturated soil with the texture of sandy clay. First, 0.8 wt% of polyacrylic acid (PAA) was added to the laboratory-prepared nanoscale Fe 3O 4 to yield the nanoscale Fe 3O 4 slurry. Thus prepared slurry was then injected into the anode reservoir of the EK set-up for remediation of nitrate-contaminated soil ([NO 3 −] = 69.39–71.65 mg/kg) in the soil compartment ( L: 25 cm; Φ: 10 cm). Application of an electric field of 1 V/cm and daily injection of nanoscale Fe 3O 4 slurry at a dose of 5 g/L were practiced during the test period of 12 d. The remediation results indicated that residual NO 3 −–N concentration of 1.35 mg/L in the anode reservoir was found to be lower than Taiwan EPA's Pollution Control Standards for Type I Groundwater Quality. In addition, a very low residual NO 3 − concentration in soil was detected. It indicates that the hybrid technology employed in this work is effective for remediation of nitrate in the subsurface following the adsorptive reduction model. The relevant reaction behavior was discussed.