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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.
Synthesis of amidoxime polymer gel to extract uranium compound from seawater by UV radiation curing
Published in Journal of Nuclear Science and Technology, 2019
Wijittra Wongjaikham, Doonyapong Wongsawaeng, Peter Hosemann
Study of Hara et al. [22] illustrated a hydrogel adsorbent prepared from acrylamide (AM) and AN. A crosslinking agent was N,N’-Methylene bisacrylamide (MBA) and an initiator of polymerization was ammonium peroxodisulfate. The produced hydrogel was tested in a solution with 4 ppb of uranium and other elements for 3 days. Results concluded that the hydrogel could adsorb uranium even in an extremely low concentration. Moreover, a research of Wongjaikham et al. [23] prepared a polymer gel with the amidoxime functional group from the mixture of AN and MAA monomers. MBA was used as a crosslinking agent and polymerization was promoted by gamma radiation from Co-60. Results revealed the highest adsorption capacity in seawater spiked with 300 ppb uranium of 6.96 mg/g adsorbent with the following optimum synthesis parameters: gamma ray dose of 40 kGy, AN:MAA ratio of 80:20 and crosslinking agent concentration of 0.8 g/100 mL.
Rapid fabrication of colloidal crystal films by spin coating using polymeric particles synthesized by dispersion polymerization
Published in Particulate Science and Technology, 2023
Thi Thu Hien Nguyen, Hoai Han Nguyen, Young-Seok Kim, Young-Sang Cho
For emulsion polymerization of PS nanospheres, 43-ml styrene were added to 345-mL H2O during stirring at 300 rpm. Then, 0.0926 g of comonomer, sodium 4-vinylbenzenesulfonate (NaSS) mixed with 20-ml H2O was added to the reaction medium, followed by nitrogen purging for 1.5 hour at elevated temperature of 70 °C. 0.196 g of initiator, potassium peroxodisulfate (KPS) dissolved in 20-mL H2O was added to promote polymerization for 18 hours.