Lignin has been derivatized with methylthioether functional groups in order to reduce its solubility in water. This new chemically modified lignin material has been used as a solid adsorbent for mercury(II) nitrate from aqueous solution. This adsorbent strongly adsorbs nitrate salts of lead(II), cadmium(II), and copper(II) from their solutions in water. The nitrate salts of the trivalent metals chromium(III) and iron(III) are also strongly adsorbed. Sodium(I) nitrate is not adsorbed from aqueous solution and calcium(II) nitrate only moderately so. These metal extraction data are compared with those obtained with methylthioether functionalized calix[4]arenes, which show a similar preference for mercury(II), but a lower preference for lead(II), cadmium(II), and iron(III).