An investigation on NO removal by wet scrubbing using NaClO2 seawater solution

Abstract

The experiments were conducted to investigate the NO removal by wet scrubbing using NaClO2 seawater solution in a cyclic scrubbing mode. Results show that, when the concentration of NaClO2 in scrubbing solution is higher than 10 mM, a complete removal of NO can be achieved during the cyclic scrubbing process. The breakthrough time for seawater with 15 mM NaClO2 is enhanced by 34.3 % compared with that for NaClO2 freshwater. The extension of the breakthrough time for NaClO2 seawater is mainly ascribed to the improved utilization of NaClO2 in the solution. The good buffering ability of seawater could suppress the acidic decomposition of NaClO2 into ClO2 effectively. The analysis of reaction products indicates that the main anions in the spent liquor are chloride ions and nitrate ions. The calculation of NaClO2 utilization according to the ion chromatography also agrees well with the experimental results of breakthrough times.

An investigation of mass transfer-reaction kinetics of NO absorption by wet scrubbing using an electrolyzed seawater solution

“…30 The articial seawater (pH 8.2, salinity 23.3 ppt) was prepared according to the ASTM D1141 standard. 1 To reduce the deterioration of electro-generated chlorine during the experiments, the electrolyte was stored in a water bath (20 C) and was shielded from light. For each gas absorption experiment, the absorbent solution was prepared by diluting the electrolyzed seawater with fresh articial seawater.…”

“…3.2.3 Reaction rate constant and validation of NO absorption rate equations. The (m + n) order rate constant (k m,n ) for the reaction (17) could be calculated by eqn (1) and (33), and the results are summarized in Table 3. The related experimental conditions were SO 2 inlet concentration of 0 ppm; solution pH of 7; and absorbent temperature of 20 C.…”

“…The emission of NO x from stationary and mobile sources is a major environmental concern due to their detrimental effects (e.g., acid rain, photochemical smog, tropospheric ozone layer depletion and even global warming) on human health and ecosystems. 1 With the implementation of stringent regulations on NO x emission, there are eager demands for developing new technologies and improving the currently used methods for NO x removal from exhaust gas.…”

NOxRemoval from Simulated Marine Exhaust Gas by Wet Scrubbing Using NaClO Solution

“…Due to its high solubility, SO 2 could be absorbed effectively by scrubbing solution. Then SO 2 was removed through the hydrolysis reaction as (18) and (19). The hydrolysis products of SO 3 2− would be oxidized by active chlorine species into SO 4 2− quickly.…”

“…Another feasible approach is to add the oxidants into the absorbent. For this purpose, various oxidants such as hydrogen peroxide (H 2 O 2 ) [13][14][15], potassium permanganate (KMnO 4 ) [16], sodium chlorite (NaClO 2 ) [17,18], calcium hypochlorite (Ca(ClO) 2 ) [19], and sodium hypochlorite (NaClO) [20][21][22][23][24] have been investigated to enhance the NO removal efficiency of the scrubbing solution. Compared with other oxidants, NaClO has some distinct advantages, such as low cost, easy availability, strong oxidative ability, easy to storage, good stability, and low toxicity.…”