Correction to: The mineralization of oxalic acid and bio-treated coking wastewater by catalytic ozonation using nickel oxide

In Table 1, “SO2-4” and “NO-3” should be corrected to “SO42−\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{S}{\mathrm{O}}_4^{2-} $$\end{document}” and “NO3−\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{N}{\mathrm{O}}_3^{-} $$\end{document}”, respectively. The original article was corrected.