Next Article in Journal
Multi-Temporal Effects of Urban Forms and Functions on Urban Heat Islands Based on Local Climate Zone Classification
Next Article in Special Issue
BP–ANN Model Coupled with Particle Swarm Optimization for the Efficient Prediction of 2-Chlorophenol Removal in an Electro-Oxidation System
Previous Article in Journal
Screening of the Maturity Status of the Tibial Tuberosity by Ultrasonography in Higher Elementary School Grade Schoolchildren
Previous Article in Special Issue
Catalytic Oxidation Process for the Degradation of Synthetic Dyes: An Overview
Open AccessArticle

Ultrasound-Enhanced Catalytic Ozonation Oxidation of Ammonia in Aqueous Solution

Jiangxi Key Laboratory of Mining & Metallurgy Environmental Pollution Control, Jiangxi University of Science & Technology, Ganzhou 341000, China
*
Author to whom correspondence should be addressed.
Int. J. Environ. Res. Public Health 2019, 16(12), 2139; https://doi.org/10.3390/ijerph16122139
Received: 21 May 2019 / Revised: 6 June 2019 / Accepted: 13 June 2019 / Published: 17 June 2019
(This article belongs to the Special Issue Advanced Oxidation Processes (AOPs) for Water Treatment)
Excessive ammonia is a common pollutant in the wastewater, which can cause eutrophication, poison aquatic life, reduce water quality and even threaten human health. Ammonia in aqueous solution was converted using various systems, i.e., ozonation (O3), ultrasound (US), catalyst (SrO-Al2O3), ultrasonic ozonation (US/O3), ultrasound-enhanced SrO-Al2O3 (SrO-Al2O3/US), SrO-Al2O3 ozonation (SrO-Al2O3/O3) and ultrasound-enhanced SrO-Al2O3 ozonation (SrO-Al2O3/US/O3) under the same experimental conditions. The results indicated that the combined SrO-Al2O3/US/O3 process achieved the highest NH4+ conversion rate due to the synergistic effect between US, SrO-Al2O3 and O3. Additionally, the effect of different operational parameters on ammonia oxidation in SrO-Al2O3/O3 and SrO-Al2O3/US/O3 systems was evaluated. It was found that the ammonia conversion increased with the increase of pH value in both systems. The NH3(aq) is oxidized by both O3 and ·OH at high pH, whereas the NH4+ oxidation is only carried out through ·OH at low pH. Compared with the SrO-Al2O3/O3 system, the ammonia conversion was significantly increased, the reaction time was shortened, and the consumption of catalyst dosage and ozone were reduced in the SrO-Al2O3/US/O3 system. Moreover, reasonable control of ultrasonic power and duty cycle can further improve the ammonia conversion rate. Under the optimal conditions, the ammonia conversion and gaseous nitrogen yield reached 83.2% and 51.8%, respectively. The presence of tert-butanol, CO32−, HCO3, and SO42− inhibited the ammonia oxidation in the SrO-Al2O3/US/O3 system. During ammonia conversion, SrO-Al2O3 catalyst not only has a certain adsorption effect on NH4+ but accelerates the O3 decomposition to ·OH. View Full-Text
Keywords: ammonia; ultrasound (US); catalytic ozonation; SrO-Al2O3 catalyst ammonia; ultrasound (US); catalytic ozonation; SrO-Al2O3 catalyst
Show Figures

Figure 1

MDPI and ACS Style

Liu, C.; Chen, Y.; He, C.; Yin, R.; Liu, J.; Qiu, T. Ultrasound-Enhanced Catalytic Ozonation Oxidation of Ammonia in Aqueous Solution. Int. J. Environ. Res. Public Health 2019, 16, 2139.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop