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Recent Advances in Oxidation and Reduction Processes for Treatment of PFAS in Water
Published in David M. Kempisty, LeeAnn Racz, Forever Chemicals, 2021
Activated persulfate is commonly applied for environmental remediation and the degradation of organic contaminants (Bruton and Sedlak, 2017). The process involves the production of sulfate (SO4•−) and •OH radicals by activating sodium persulfate (Na2S2O8) with thermal, transition metal, or UV activation methods. In their previous book, Kempisty et al. (2018) showed that activated persulfate can decompose perfluorinated carboxylic acids (PFCA) (and to a lesser extent perfluorinated sulfonic acids - PFOS); however, this would only be under the conditions of high persulfate doses, high temperature or extreme pH.
Contaminated site remediation: Role and classification of technologies
Published in Katalin Gruiz, Tamás Meggyes, Éva Fenyvesi, Engineering Tools for Environmental Risk Management – 4, 2019
Persulfate is generally used in the form of peroxydisulfate (S2O8−). It easily dissolves in water, leaves no harmful by-products and is easier to handle compared to peroxide or ozone. Persulfate itself is reactive but sulfate radicals derived from the persulfate by activation degrade a wider range of contaminants and work faster. The most common activator is iron II (ferrous iron) but zero valent iron (ZVI) and many other agents can be applied as catalysts: UV, heat, high pH, transition metals, and hydrogen peroxide.
In situ Treatment Technologies
Published in Rong Yue, Fundamentals of Environmental Site Assessment and Remediation, 2018
Persulfate is a strong oxidizing agent that is capable of breaking down many common contaminants. The standard ORP for the persulfate to sulfate reaction is relatively high (+2.0 V; refer to Table 8.1). However, unlike permanganate, the direct reaction of persulfate anion with organic compounds appears to be slow. Studies have found that free radicals can be generated by the activation or catalysis of persulfate solution; these have an even higher oxidation potential and can react with faster kinetics.
Degradation of carbamazepine from wastewater by ultrasound-enhanced zero-valent iron -activated persulfate system (US/Fe0/PS): kinetics, intermediates and pathways
Published in Environmental Technology, 2022
Xuezheng Huang, Zhifei Wang, Zengwu Sun, Zhenjun Wang
Because persulfate itself is relatively stable, it can't directly and effectively remove organic pollutants. However, when PS is activated, is converted to , and the strong oxidative properties of , are used to degrade organic matter [32,33]. In the above reaction, except for the US/Fe0 system, the essence of other reaction systems is the optimal combination of different activation methods. The degradation efficiency of US//PS system is significantly higher than that of other systems, indicating that the combined activation method can greatly improve the oxidation performance of the system. The quasi-first-order reaction kinetics fitting curves of carbamazepine in different reaction systems are shown in Figure 3.
Reactive Green 19 degradation using O3/S2 O8(2-) process: Intermediates and Proposed Degradation Pathway
Published in Ozone: Science & Engineering, 2022
Nur Aqilah Mohd Razali, Che Zulzikrami Azner Abidin, Soon an Ong, Muhammad Ridwan Fahmi, Abdul Haqi Ibrahim, Siti Nasuha Sabri, Su Huan Kow, Safya Abdul Malik
Due to the lack of applicability of industrial technology, few researchers have shown interest in this method for the treatment of dye wastewater. Thus, persulfate is suitable for enhancing the ozonation process because it can generate sulfate radicals attack through the one electron oxidation mechanism but would cause a limitation of the scavenging effect in dissolved organic matter and inorganic ions (Ahmed et al. 2012; Monteagudo et al. 2016). Several characteristics of persulfate make it particularly attractive as a catalyst and it is one of the strongest oxidants due to its stable solid appearance at ambient temperature, ease of storage and transport, high stability, high aqueous solubility and relatively low cost (Xu et al. 2012). Hence, Mohajerani, Mehrvar, and Ein-Mozaffari (2009) reviewed by employing synthetic dyes in a study is a helpful way and more beneficial to analyze, separate, degrade, and mineralize various intermediates.
Current status of soil and groundwater remediation technologies in Taiwan
Published in International Journal of Phytoremediation, 2021
The Fenton’s reagent uses hydrogen peroxide (H2O2) and iron salts as a catalyst to react with one another. The reaction yields hydroxyl radicals (·OH), which are highly reactive and oxidize contaminants of soil or groundwater, such as chlorinated solvents. Due to the precipitating properties of iron the pH-level of the medium usually has to be decreased, which may have an adverse impact on the ecology. Ozone is a gaseous fluid that only leaves dioxygen (O2) behind after treatment. Unfortunately, this oxidant also reacts easily with other chemicals that are not considered as contaminants. The compounds permanganate (KMnO4) and sodium permanganate (NaMnO4) have a lower reaction time, contributing in penetration of more volume of the medium and further spread. Sodium persulfate Na2S2O8 has high solubility and leaves only a small amount of residual compounds. When applying to soil or groundwater, sodium persulfate is activated to derive the cation sulfate radical SO4¯, which reacts with many contaminants. Persulfate is persistent in soil and less harmful to microorganisms present at the site.