Porous carbon nanospheres prepared using spray pyrolysis were evaluated as adsorbents for removal of arsenate and selenate in de-ionized (DI), canal, and well waters. The carbon nanospheres displayed good binding to both metals in DI water and outperformed commercial activated carbons for arsenate removal in pH > 8, likely due to the presence of basic surface functional groups, high surface-to-volume ratio, and suitable micropores formed during the synthesis.