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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.
Remediation of PFAS-Contaminated Soil
Published in David M. Kempisty, Yun Xing, LeeAnn Racz, Perfluoroalkyl Substances in the Environment, 2018
Konstantin Volchek, Yuan Yao, Carl E. Brown
In situ chemical oxidation using peroxydisulfate (S2O82−), often simply referred to as persulfate, is a promising technique for soil remediation. The process has previously been used for the remediation of pollutants such as chlorinated ethenes and benzenes; oxygenates; benzene, toluene, ethylbenzene, and xylene (BTEX); and PAHs from soil (Nadim et al. 2006; Tsitonaki et al. 2010). Persulfate can first be delivered to the soil subsurface in an inactive form, and then activated once contact with the contaminated zone has occurred. An example of a delivery system would be a network of high-pressure injection points, followed by mixing of the soil with a backhoe (Tsitonaki et al. 2010). The activated persulfate radical can be produced through ultraviolet exposure, heat, high pH (alkaline conditions), hydrogen peroxide, and a variety of transition metals (Watts and Teel 2006). Activation by heat can be accomplished using steam injection. Heat can also be incorporated into the soil using six-phase soil heating, which involves the use of electricity to pass current through the soil, resulting in thermal energy production (Heine and Steckler 1999). Six-phase soil heating can be used as a stand-alone soil remediation technique for more volatile compounds, as it encourages their release from the soil matrices. Nadim et al. (2006) used a complex of divalent iron Fe (II) with ethylenediaminetetraacetic acid (EDTA) to activate persulfate for the degradation of PAHs. The addition of a chelating agent effectively kept the Fe (II) in solution even at neutral pH.
Enhanced electron transfer for activation of peroxymonosulfate via MoS2 modified iron-based perovskite
Published in Environmental Technology, 2022
Sheng Sheng, Jingjing Fu, Siyuan Song, Yuxuan He, Jin Qian, Ziyang Yi
Advanced oxidation processes (AOPs) produce a large number of radicals in the reaction, which can partially or even completely mineralise many difficult to degrade organic pollutants into carbon dioxide, water and inorganic ions. Persulfate activation is an advanced oxidation technique that degrades pollutants using SO4•− as the main active species [6]. Compared to the traditional Fenton method, persulfate-based AOPs enjoy many advantages, such as low cost, ease of storage and transport, and a wide operating pH range (3.0 ∼ 10.0) [7]. In addition, the free radical SO4•− has a much longer half-life than •OH and is able to attack pollutants continuously [8]. In persulfate-based AOPs, the asymmetric structure of peroxymonosulfate (PMS) allows for easier activation and faster reaction rates than the symmetrical structure of peroxydisulfate (PDS) [9].
Preparation and evaluation of polymer-encapsulated UV filter nanocapsules with miniemulsion polymerization
Published in Journal of Dispersion Science and Technology, 2021
Qing An, Xinjiong Ni, Dong Liu, Yun Zhang, Yuhua Cao
Styrene (St), methacrylic acid (MAA), MMA, ether, ethanol, sodium hydroxide (NaOH), dimethyl sulfoxide (DMSO), stearic acid, isopropanol, propylene glycol, triethanolamine and potassium peroxydisulfate (analytical grade), lanolin and isopropyl myristate (IPM) (chemical pure), as well as homosalate (98%) were purchased from Sinopharm Chemical Reagent Co. Ltd. OD-PABA (98%) was obtained from American ISP. EGDMA (99%) was purchased from Belling Technology Co. Ltd. 2,2-Azo-bis-iso-butyronitrile (AIBN) purchased from Shanghai No.4 Reagent & H.V. Chemical Co. Ltd. was used after recrystallization. Deionized water was prepared with a Milli-Q system (Millipore, Billerica, MA, America) with a resistivity of 18 MΩ·cm. Dulbecco’s modified eagle medium (DMEM) (Gibco, America), phosphate buffer saline (PBS) (Gibco, America), penicillin-atreptomycin (Gibco, America), fetal bovine serum (FBS) (AusgeneX, Australia), and 0.25% trypsin-EDTA (Gibco, America) were purchased from thinkfar biotechnology Co. Ltd. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) was purchased from Sigma Co. Ltd.
Nitrogen-doped graphene/poly(3,4-ethylenedioxythiophene) as metal-free electrode material for high-performance supercapacitor applications
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Narendranath Jonna, Manokaran Janakiraman, Shanmuga Sundar Saravananbhavan, Kannan Natarajan, Peng Cao, Balasubramanian Natesan
Composite of NG/PEDOT was prepared by a mixture of EDOT monomer, Iron(III) chloride oxidant, ammonium peroxydisulfate, and polystyrene sulfonate (PSS). PSS solution was prepared by adding 5.85 g to 100 ml of water. Here, PSS acts as both dispersant and dopant for the preparation of PEDOT. Meantime EDOT monomer solution is prepared by 1 ml of 0.1 M EDOT in 100 ml of 1 M HCl. After which 0.5 M of iron(III) chloride and 0.5 M of ammonium peroxydisulfate solutions were also prepared. Iron(III) chloride acts as an oxidant and ammonium chloride acts as an initiator for the polymerization reaction. EDOT was added bit by bit to PSS solution on stirring condition for 2 h. To initiate polymerization, ammonium peroxydisulfate is injected alongside with oxidant FeCl3 (Alvi et al. 2011; Zhao et al. 2015) slowly with stirring. The color changes from green to dark blue and to black. The polymerization is allowed for 24 h as process in Figure 2 by continuous stirring. The polymer obtained is filtered by vacuum filtration method and dried at controlled temperature.