Reducing energy cost of <i>in situ</i> nitrogen fixation in water using an arc-DBD combination
Duy Khoe Dinh, Muzammil Iqbal, Woo Seok Kang, Daewoong Kim, Dae Hoon Lee
Abstract
Abstract In this study, a sustainable air plasma-based nitrogen fixation into reactive nitrogen species in water (e.g. nitrate and nitrite) is presented, which mimics the lightning-based nitrogen fixation that occurs in nature. We report a hybrid plasma system that combines a dielectric barrier discharge (DBD) reactor (as an efficient ozone source) and an arc plasma reactor (as an efficient NO x source). This hybrid plasma system completely converts gaseous NO x and O 3 into <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mtext>NO</mml:mtext> </mml:mrow> <mml:mrow> <mml:mi>x</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> in water with almost zero emissions (NO x and O 3 ). Gaseous outlets, in-liquid species, and electrical parameters were investigated. The energy cost for nitrate production via a single-pass reaction was extremely reduced to 8 MJ mol −1 , which enhanced the applicability of the direct one-step nitrogen fixation into <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mtext>NO</mml:mtext> </mml:mrow> <mml:mrow> <mml:mi>x</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> in water for distributed fertilizer production to decrease the dependence on the Haber–Bosh process toward sustainable agricultural development.