Development of continuous system based on nanoscale zero valent iron particles for phosphorus removal

Abstract

Nanoscale Zero Valent Iron (NZVI) is one of the materials that have gained attention in the field of water treatment and environmental remediation in recent years. The main purpose of this study is to develop and evaluate a phosphorus removal system using NZVI particles. The NZVI used for the experiments was synthesized under optimum conditions using the chemical reduction method. This continuous system consisted of Continuous Stirred Flask Reactor (CSFR), settler, polishing unit, and sand column. The continuous experiment showed that 73.84% phosphorus was removed mainly at CSFR. Further, 80.62% total iron was removed and recycled at the settler. Based on the continuous operation results, there was a strong relationship between iron concentration and ORP value (R 2 = 0.9969). This result indicated that ORP would be an important monitoring parameter while operating the continuous system. The aerobic condition contributed the highest phosphorus overall removal efficiency (91.37%) due to the enhancement of iron corrosion. Copper bimetal particles also achieved the highest removal efficiency (94.96%) after increasing the active site and decreasing the solution pH. Finally, comparing the aerobic and bimetallic cases, we concluded that the bimetallic case is the best condition for removing phosphorus because it could treat large solution volume than the aerobic one could.