A strong adsorbent TEA-GO for Cu²⁺ is prepared using TEA modified GO nanosheets. FT-IR and XPS results show that epoxy groups on GO are eliminated, and simultaneously hydroxyl groups and C–N dominate the surface groups of TEA-GO. The increased equilibrium capacity of TEA-GO for a high initial concentration of Cu²⁺ makes it a promising adsorbent for heavy metal ions.