Simultaneous Thermal Activation of Persulfate/Fenton System for High-Concentration N,N-Dimethylacetamide Degradation: Parameter Optimization and Degradation Mechanism

The research aim was to investigate phase development after pozzolanic reaction between metakaolin (MK) and calcium hydroxide (CH) with alkaline and thermal activations. The CH to MK ratio (C/M) of 0.4 generating CaO/SiO2 of 1.18 was selected in this study. Various concentrations of NaOH solutions (0.01, 0.1, 1, 3, 5 and 10 M) were used. The alkali activated samples were thermally activated at 25 °C, 70 °C, 90 °C and 130 °C for 4 h. Phase development under thermal activation of alkali activated metakaolin based system were investigated. At every temperature, C/M mixtures with 0.01 and 0.1 M NaOH promoted the formations of poorly crystalline calcium silicate hydrate (C-S-H(I)) and calcium aluminosilicate hydrate (CASH) compounds. With 3 and 5 M NaOH activations, sodium aluminosilicate hydrate (NASH) and sodium calcium silicate hydrate (NCSH) was formed. 1 M NaOH was found to be a boundary of phase transformation from C-S-H(I) and CASH to NASH and NCSH. In addition, zeolite X and sodalite appeared when NaOH solution reached 10 M. Thermal activation significantly affected phase development at high concentration of alkaline activation (1-10 M). At 1 M NaOH, NASH compounds in a form of gmelinite and zeolite ZK-14 were found at 70-90 °C. At 3-5 M, katoite was found at 70-130 °C. At 10 M, zeolite X was found at 70-90 °C. Sodalite was also found at 130 °C with 10 M NaOH.

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Enhanced degradation of organic wastewater containing p-nitrophenol by a novel wet electrocatalytic oxidation process: Parameter optimization and degradation mechanism

Separation and Purification Technology ◽

10.1016/j.seppur.2007.10.006 ◽

2008 ◽

Vol 61 (2) ◽

pp. 123-129 ◽

Cited By ~ 35

Author(s):

Q DAI ◽

L LEI ◽

X ZHANG

Keyword(s):

Parameter Optimization ◽

Electrocatalytic Oxidation ◽

Oxidation Process ◽

Degradation Mechanism ◽

Process Parameter ◽

Process Parameter Optimization ◽

Enhanced Degradation ◽

Organic Wastewater

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Distribution of Fe(II) Concentration during Degradation of Rhodamine B by Fenton Reagent

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.261-263.744 ◽

2011 ◽

Vol 261-263 ◽

pp. 744-748

Author(s):

Xiao Xia Ou ◽

Feng Jie Zhang ◽

Chong Wang ◽

Yun Na Wu ◽

Juan Du

Keyword(s):

Humic Acid ◽

Oxalic Acid ◽

Rhodamine B ◽

Fenton Reaction ◽

Fenton Reagent ◽

High Concentration ◽

Reaction Conditions ◽

Optimal Reaction ◽

Fenton System ◽

Apparent Influence

The effects of reaction conditions including Fe2+, H2O2, oxalic acid, and humic acid dosages were discussed on the Fenton degradation of rhodamine B (RB). The optimal reaction conditions of Fenton reaction were 0.15 mM Fe2+, 5 mM H2O2, and pH 3.0, and the decolorization rate RB (10 mg/L) reached 97.8% after 30min catalytic degradation. The changes of Fe2+concentrations in Fenton system has been focused on in this work. A relatively low concentration of Fe2+was maintained during reaction process when Fe2+and H2O2were added with high concentration, and thus RB was degraded quickly. The results implicated that Fe2+dosage played a very important role in the degradation of RB, and H2O2dosage didn’t have an apparent influence on the degradation of RB in general. The Fenton degradation of RB could be inhibited in the presence of oxalic acid and humic acid, especially at a high concentration of oxalic acid and humic acid.

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Use of an Ultraviolet Light activated Persulfate Process to Degrade Humic Substances: Effects of Wavelength and Persulfate Dose

10.21203/rs.3.rs-175564/v1 ◽

2021 ◽

Author(s):

Yiming Fang ◽

Hiroshi Sakai

Keyword(s):

Hydrogen Peroxide ◽

Molecular Weight ◽

Drinking Water ◽

Humic Substances ◽

Degradation Mechanism ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Lower Molecular Weight ◽

High Concentration ◽

Activated Persulfate

Abstract Natural organic matter (NOM), commonly found in surface and ground waters, form Disinfection by-products in drinking water. Generally, advanced oxidation processes (AOPs) featuring hydrogen peroxide are used to treat water, however, sulfate radical recently has been used to treat recalcitrant organics, because it is associated with a higher oxidation potential and more effective removal than hydroxyl radicals. Hence, in this research, we evaluated persulfate oxidation efficiency in terms of reductions in humic substances levels and investigated the degradation mechanism. The results showed that ultraviolet activated persulfate effectively treated humic substances compared with hydrogen peroxide and direct irradiation. Treatment was dose- and wavelength-dependent; higher persulfate concentrations or shorter UV wavelengths were more effective for treating humic substances as high concentration sulfate radicals were created. The degradation mechanism was similar to that of hydrogen peroxide. Aromatic and chromophore components were more susceptible to degradation than were lower molecular weight components, being initially decomposed into the latter, reducing UV254 absorbance and the SUVA254. Lower molecular weight materials were eventually degraded to end products: NPOC levels fell. And we also treated the inflow of a drinking water treatment plant with persulfate, and humic substances were effectively removed.

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