Supercritical water oxidation and process enhancement of nitrogen-containing organics and ammonia

Li, Jianna; Wang, Shuzhong; Li, Yanhui; Jiang, Zengliang; Xu, Tiantian; Zhang, Yishu

doi:10.1016/j.watres.2020.116222

Cited by 40 publications

(2 citation statements)

References 134 publications

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“…According to Li et al [35], when H 2 O 2 is used as an oxidant, the hydrogen abstraction phase occurs according to the reactions presented in Equations ( 15)-( 17) [35].…”

Section: Supercritical Water Oxidation Treatment and Organic Degradationmentioning

confidence: 99%

Continuous Treatment of Refractory Wastewater from Research and Teaching Laboratories via Supercritical Water Oxidation–Experimental Results and Modeling

Pereira,

Meireles de Souza,

Dias

et al. 2023

Water

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Teaching and research laboratories generate wastes of various compositions and volumes, ranging from diluted aqueous solutions to concentrated ones, which, due to milder self-regulation waste-management policies, are carelessly discarded, with little attention given to the consequences for the environment and human health. In this sense, the current study proposes the application of the supercritical water oxidation (SCWO) process for the treatment of complex refractory wastewater generated in research and teaching laboratories of universities. The SCWO, which uses water in conditions above its critical point (T > 647.1 K, p > 22.1 MPa), is regarded as an environmentally neutral process, uniquely adequate for the degradation of highly toxic and bio-refractory organic compounds. Initially, the wastewater samples were characterized via headspace gas chromatography coupled with mass spectrometry. Then, using a continuous tubular reactor, the selected operational parameters were optimized by a Taguchi L9 experimental design, aiming to maximize the total organic carbon reduction. Under optimized conditions—that is, temperature of 823.15 K, feed flow rate of 10 mL min−1, oxidizing ratio of 1.5 (50% excess over the oxygen stoichiometric ratio), and sample concentration of 30%—TOC, COD, and BOD reductions of 99.9%. 91.5% and 99.2% were achieved, respectively. During the treatment process, only CO2, methane, and hydrogen were identified in the gaseous phase. Furthermore, the developed methodology was applied for the treatment of wastewater samples generated in another research laboratory and a TOC reduction of 99.5% was achieved, reinforcing the process’s robustness. A thermodynamic analysis of SCWO treatment of laboratory wastewater under isothermal conditions was performed, using the Gibbs energy minimization methodology with the aid of the GAMS® 23.9.5. (General Algebraic Modeling System) software and the CONOPT 4 solver. Therefore, the results showed that SCWO could be efficiently applied for the treatment of wastewater generated by different teaching and research laboratories without the production of harmful gases and the addition of hazardous chemicals.

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“…According to Li et al [35], when H 2 O 2 is used as an oxidant, the hydrogen abstraction phase occurs according to the reactions presented in Equations ( 15)-( 17) [35].…”

Section: Supercritical Water Oxidation Treatment and Organic Degradationmentioning

confidence: 99%

Continuous Treatment of Refractory Wastewater from Research and Teaching Laboratories via Supercritical Water Oxidation–Experimental Results and Modeling

Pereira,

Meireles de Souza,

Dias

et al. 2023

Water

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“…The water quality of the wastewater is similar to that of coking wastewater, but the COD concentration of semi-coking wastewater is approximately 10 times higher, and the concentrations of ammonia nitrogen and phenols are also significantly higher than coking wastewater ( Bokun et al, 2020 ). Semi-coking wastewater is the most harmful type of wastewater due to its high COD and high toxicity ( Ma et al, 2017 ; Zhou et al, 2017 ; Li et al, 2020 ). Thus, the method of treating these wastewaters has always been the subject of intensive research ( Wang et al, 2017 ; Maalouf and El-Fadel, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

Self-doped N, S porous carbon from semi-coking wastewater-based phenolic resin for supercapacitor electrodes

Yan

Wang²,

Wang³

et al. 2022

Front. Chem.

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Contamination of phenolic compounds has devastating effects on the environment. Therefore, its harmless treatment and recycling have received extensive attention. Herein, a novel method for preparing N-S doped phenolic resin (NSPR) from phenols, N and S groups in semi-coking wastewater, and formaldehyde are developed. The KOH is consequently incorporated into the NSPR through simultaneous carbonization and activation in a single step to produce porous carbon material (NSPC). The as-obtained NSPC exhibits a high specific capacitance of 182 F g−1 at 0.5 A g−1, a high energy density of 9.1 Wh kg−1 at a power density of 0.15 kW kg−1, and remarkable cycling stability in aqueous KOH electrolyte. This outstanding electrochemical performance is attributed to its ultrahigh specific surface area (SSA, 2,523 m2 g−1), enormous total pore volume (Vt, 1.30 cm3 g−1), rational pore structure, and N-S heteroatom self-doping (0.76 at% N and 0.914 at% S), which ensures adequate charge storage, rapid electrolyte ion diffusion, and contributed pseudo-capacitance. This work not only provides a facile method for transforming phenolic wastewater into high-value products but also offers a cost-effective and high-performance porous carbon material for supercapacitors.

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Energy conversion and utilization in supercritical water oxidation systems: A review

Zhang

Liang

et al. 2022

Biomass and Bioenergy

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Supercritical water oxidation and process enhancement of nitrogen-containing organics and ammonia

Cited by 40 publications

References 134 publications

Continuous Treatment of Refractory Wastewater from Research and Teaching Laboratories via Supercritical Water Oxidation–Experimental Results and Modeling

Continuous Treatment of Refractory Wastewater from Research and Teaching Laboratories via Supercritical Water Oxidation–Experimental Results and Modeling

Self-doped N, S porous carbon from semi-coking wastewater-based phenolic resin for supercapacitor electrodes

Energy conversion and utilization in supercritical water oxidation systems: A review

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