Engineered Graphite Oxide Materials for Application in Water Purification

TLDR

The authors covalently graft thiol groups onto the sp2 domains of hydrophilic graphite‑oxide nanosheets via diazonium chemistry and assemble the modified GO onto sand granules to form core–shell adsorbent granules suitable for filtration columns. The thiol‑modified GO adsorbs six times more mercuric ions than unmodified GO, and GO‑coated sand retains at least five times more heavy metals and organic dyes than pure sand, suggesting a low‑cost water purification solution for developing economies.

Abstract

Retaining the inherent hydrophilic character of GO (graphite-oxide) nanosheets, sp2 domains on GO are covalently modified with thiol groups by diazonium chemistry. The surface modified GO adsorbs 6-fold higher concentration of aqueous mercuric ions than the unmodified GO. "Core–shell" adsorbent granules, readily useable in filtration columns, are synthesized by assembling aqueous GO over sand granules. The nanostructured GO-coated sand retains at least 5-fold higher concentration of heavy metal and organic dye than pure sand. The research results could open avenues for developing low-cost water purification materials for the developing economies.