Exhaustive Conversion of Inorganic Nitrogen to Nitrogen Gas Based on a Photoelectro-Chlorine Cycle Reaction and a Highly Selective Nitrogen Gas Generation Cathode

Abstract

A novel method for the exhaustive conversion of inorganic nitrogen to nitrogen gas is proposed in this paper. The key properties of the system design included an exhaustive photoelectrochemical cycle reaction in the presence of Cl, in which Cl· generated from oxidation of Cl by photoholes selectively converted NH to nitrogen gas and some NO or NO. The NO or NO was finally reduced to nitrogen gas on a highly selective Pd-Cu-modified Ni foam (Pd-Cu/NF) cathode to achieve exhaustive conversion of inorganic nitrogen to nitrogen gas. The results indicated total nitrogen removal efficiencies of 30 mg L inorganic nitrogen (NO, NH, NO/NH = 1:1 and NO/NO/NH = 1:1:1) in 90 min were 98.2%, 97.4%, 93.1%, and 98.4%, respectively, and the remaining nitrogen was completely removed by prolonging the reaction time. The rapid reduction of nitrate was ascribed to the capacitor characteristics of Pd-Cu/NF that promoted nitrate adsorption in the presence of an electric double layer, eliminating repulsion between the cathode and the anion. Nitrate was effectively removed with a rate constant of 0.050 min, which was 33 times larger than that of Pt cathode. This system shows great potential for inorganic nitrogen treatment due to the high rate, low cost, and clean energy source.

Rapid and selective electrochemical transformation of ammonia to N2 by substoichiometric TiO2-based electrochemical system

“…It is known that OHc, Clc and HClO are strong oxidants that can react with NH 4 + . 16 In particular, the Clc could react selectively with NH 4 + (k Clc ¼ 5 Â 10 13 M À1 s À1 ) 33 with a much higher reaction rate compared with that of OHc (k OHc ¼ 3 Â 10 8 M À1 s À1 ). 34 These Clc can selectively convert NH 4 + into N 2 , NO 3 À or NO 2 À (eqn (5)-(7)).…”

“…The fabrication of a Pd-Cu/NF electrode followed a previously reported electrodeposition method. 14,16 Briey, the NF support was cleaned by sequential sonication in H 2 SO 4 , acetone, and DI water to remove the surface oxidized layer before use. The electrolyte solution consisted of 2 mM PdCl 2 , 4 mM CuSO 4 -$5H 2 O and 0.1 M HCl.…”

Efficient Hydrogen Generation and Total Nitrogen Removal for Urine Treatment in a Neutral Solution Based on a Self-Driving Nano Photoelectrocatalytic System

“…Preparation of the WO 3 nanosheets photoanode referred to the method found in previous research [37][38][39]. The TiO 2 /WO 3 nanosheets photoanode was prepared through a hydrothermal method, on the basis of the WO 3 photoanode [33].…”

A Bifunctional Electroactive Ti4O7-Based Membrane System for Highly Efficient Ammonia Decontamination

“…The mixture was transferred in module (D = 1.2 cm) and a pressure of~50 kg was applied by a hydraulic tablet machine (Lixin experimental instrument, Shenzhen, China). The sheets were sintered in a tube furnace at N 2 atmosphere at 900 • C for 6 h. The fabrication of Pd-Cu/NF, Pd/NF, and Cu/NF electrodes followed a previously reported electrodeposition method [39].…”