Removal of sulfamethoxazole by electrochemically activated sulfate: Implications of chloride addition.

Title Removal of sulfamethoxazole by electrochemically activated sulfate: Implications of chloride addition.
Authors J. Radjenovic; M. Petrovic
Journal J Hazard Mater
DOI 10.1016/j.jhazmat.2017.03.040
Abstract

Electrochemical oxidation is considered to be an attractive alternative to chemical oxidation for the treatment of polluted water. Given the of ability of boron-doped diamond (BDD) electrodes to generate hydroxyl radicals (OH), they are often selected for the degradation of persistent organic contaminants. Recently, BDD anodes have been demonstrated to form strong oxidants, sulfate radicals (SO4(-)), directly from sulfate ions. In this study, electrochemical activation of sulfate to SO4(-) at BDD anodes enhanced the removal of an antibiotic sulfamethoxazole (SMX). The rate of SMX oxidation was 6 times higher in sulfate anolyte compared to inert nitrate anolyte. Addition of chloride accelerated the disappearance of SMX in both anolytes due to electrochlorination. Yet, mineralization efficiency was decreased, particularly in Na2SO4 anolyte due to the scavenging of SO4(-) by Cl(-). Electrogenerated SO4(-) yielded nitroso- and nitro-derivatives, which were not observed in the absence of sulfate. The peak intensities of chlorinated TPs were three orders of magnitude lower in Na2SO4 than in NaNO3 anolyte, suggesting that addition of sulfate may lower the formation of chlorinated organics. However, attention should be paid to the formation of inorganic byproducts, as the formation rates of toxic chlorate and in particular perchlorate were higher in Na2SO4 anolyte.

Citation J. Radjenovic; M. Petrovic.Removal of sulfamethoxazole by electrochemically activated sulfate: Implications of chloride addition.. J Hazard Mater. 2017;333:242249. doi:10.1016/j.jhazmat.2017.03.040

Related Elements

Chlorine

Chlorine is a Block P, Group 17, Period 3 element. Its electron configuration is [Ne]3s23p5. The chlorine atom has a covalent radius of 102±4 pm and its Van der Waals radius is 175 pm. Chlorine ModelIn its elemental form, chlorine is a yellow-green gas. Chlorine is the second lightest halogen after fluorine. It has the third highest electronegativity and the highest electron affinity of all elements, making it a strong oxidizing agent. It is rarely found by itself in nature. Chlorine was discovered and first isolated by Carl Wilhelm Scheele in 1774. It was first recognized as an element by Humphry Davy in 1808.

Sulfur

See more Sulfur products. Sulfur (or Sulphur) (atomic symbol: S, atomic number: 16) is a Block P, Group 16, Period 3 element with an atomic radius of 32.066. Sulfur Bohr ModelThe number of electrons in each of Sulfur's shells is 2, 8, 6 and its electron configuration is [Ne] 3s2 3p4. In its elemental form, sulfur has a light yellow appearance. The sulfur atom has a covalent radius of 105 pm and a Van der Waals radius of 180 pm. In nature, sulfur can be found in hot springs, meteorites, volcanoes, and as galena, gypsum, and epsom salts. Sulfur has been known since ancient times but was not accepted as an element until 1777, when Antoine Lavoisier helped to convince the scientific community that it was an element and not a compound.

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