In mining processes, nitrate is released into the environment due to the use of N-based explosives and leaching agents such as cyanide. The present study assessed the effect of Ni on denitrification in fluidized-bed reactors (FBRs) at 7-8 and 22oC. In absence of nickel, the feed acidic pH was neutralized due to the pH buffering produced by denitrification and the FBR internal recycling. At feed pH of 2.5 and 5.5 mg/L of Ni, nitrate and nitrite removals were not inhibited. However, effluent pH decreased to 5.0. At feed pH of 5.5, denitrification was efficiently maintained even at 100 mg/L Ni, resulting in complete nitrate removal and stable effluent pH of 7.1. In summary, denitrification tolerated high nickel concentrations demonstrating to be suitable for mining water treatment.
Impact of Ni2+ on denitrification of mining waters in fluidized-bed reactors
PAPIRIO, Stefano;
2014-01-01
Abstract
In mining processes, nitrate is released into the environment due to the use of N-based explosives and leaching agents such as cyanide. The present study assessed the effect of Ni on denitrification in fluidized-bed reactors (FBRs) at 7-8 and 22oC. In absence of nickel, the feed acidic pH was neutralized due to the pH buffering produced by denitrification and the FBR internal recycling. At feed pH of 2.5 and 5.5 mg/L of Ni, nitrate and nitrite removals were not inhibited. However, effluent pH decreased to 5.0. At feed pH of 5.5, denitrification was efficiently maintained even at 100 mg/L Ni, resulting in complete nitrate removal and stable effluent pH of 7.1. In summary, denitrification tolerated high nickel concentrations demonstrating to be suitable for mining water treatment.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
