twocolumn mode #balance<>Balanced columns #sep<>Column separation #doublerule<>Double columnseprule layouts/layout#onecolAbstract<>onecolumn abstract in twocolumn mode double columnseprule
\documentclass[twocolumn]{article}
\newcommand*{\realcolumnseprule}{}
\let\realcolumnseprule\columnseprule
\def\columnseprule{\realcolumnseprule
  \hskip5\realcolumnseprule
  \vrule width\realcolumnseprule
}
\setlength{\realcolumnseprule}{.4pt}

\begin{document}
test\newpage test
\end{document}
Balanced columns
Load package balance.sty
Column separation
Set in the preamble for example \setlength\columnsep{20pt}. The default value is 10pt.