Removal of NO₃^– from groundwater by PP-g-AA-Am non-woven fabric using fixed-bed column reactors

This study investigated the effect of PP-g-AA-AM non-woven fabric on the removal of nitrate nitrogen from groundwater. The breakthrough time was 1.5–2.6, 2.5–5.5, and 6.2–12.2 h for a superficial velocity of 2.0, 1.0, and 0.5 cm/s, respectively, for the nitrate nitrogen concentration in groundwater to satisfy the safe standard for drinking of 10 mg/L (as per the Ministry of Environment in Korea's 2011 Management of Drinking Water Act); the slower the superficial velocity, the longer is the breakthrough time. The ion exchange amount was a maximum of 28.37 mg/g for a superficial velocity of 2.0 cm/s, and the ion exchange amount decreased with slower or faster superficial velocities. The ratio of adsorbent used shows a linear relationship with the column diameter to length ratio and an inverse one with the superficial velocity. It is a maximum of 79% for a superficial velocity of 0.5 cm/s and a column diameter to length ratio of 1:10. Multiple regression analysis with the superficial velocity, nitrate nitrogen concentration in groundwater, and column diameter to length ratio showed that the initial nitrate nitrogen concentration has the strongest influence on the ion exchange amount. A 10% NaCl regenerant solution of 20 times the reactor volume is required to accomplish >99% of ion exchange bed regeneration in a groundwater treatment facility when applied to a packed column filled with PP-g-AA-Am.