CHAPTER 14. The Engineering of Continuous Hydrothermal/Solvothermal Synthesis of Nanomaterials

Lester, Edward; Dunne, Peter W.; Chen, Yipei; Al-Atta, Ammar

doi:10.1039/9781788013543-00416

Cited by 2 publications

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“…The formulation of metal oxide nanoparticles by supercritical water oxidation is one of the rapid green methods due to quick and continuous mixing of supercritical water stream with a cold metal salts solution stream in reactor volume. Different reactor geometries had been used to mix these two fluids, starting from very basic T-and Y-shaped, tube-in-tube configurations to more complex mechanical hybrid designs (Lester et al 2018). The tube-in-tube counter-current mixing design uses the natural convection that arises from the difference of densities between supercritical water and the cold flow to creates efficient mixing between reagents (Lester et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Supercritical water oxidation of phenol and process enhancement with in situ formed Fe2O3 nano catalyst

Al-Atta

Sher

Hazafa

et al. 2021

Environ Sci Pollut Res

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During the past few decades, the treatment of hazardous waste and toxic phenolic compounds has become a major issue in the pharmaceutical, gas/oil, dying, and chemical industries. Considering polymerization and oxidation of phenolic compounds, supercritical water oxidation (SCWO) has gained special attention. The present study objective was to synthesize a novel in situ Fe2O3nano-catalyst in a counter-current mixing reactor by supercritical water oxidation (SCWO) method to evaluate the phenol oxidation and COD reduction at different operation conditions like oxidant ratios and concentrations. Synthesized nano-catalyst was characterized by powder X-ray diffraction (XRD) and transmission electron microscope (TEM). TEM results revealed the maximum average particle size of 26.18 and 16.20 nm for preheated and non-preheated oxidant configuration, respectively. XRD showed the clear peaks of hematite at a 2θ value of 24, 33, 35.5, 49.5, 54, 62, and 64 for both catalysts treated preheated and non-preheated oxidant configurations. The maximum COD reduction and phenol oxidation of about 93.5% and 99.9% were observed at an oxidant ratio of 1.5, 0.75 s, 25 MPa, and 380 °C with a non-preheated H2O2 oxidant, while in situ formed Fe2O3nano-catalyst showed the maximum phenol oxidation of 99.9% at 0.75 s, 1.5 oxidant ratio, 25 MPa, and 380 °C. Similarly, in situ formed Fe2O3 catalyst presented the highest COD reduction of 97.8% at 40 mM phenol concentration, 1.0 oxidant ratio, 0.75 s residence time, 380 °C, and 25 MPa. It is concluded and recommended that SCWO is a feasible and cost-effective alternative method for the destruction of contaminants in water which showed the complete conversion of phenol within less than 1 s and 1.5 oxidant ratio.

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Section: Introductionmentioning

confidence: 99%