A lignosulfonate-modified graphene hydrogel with ultrahigh adsorption capacity for Pb(II) removal

A lignosulfonate-modified graphene hydrogel (LS-GH) for Pb(II) adsorption was synthesized through a one-step method. The three-dimensional (3D) porous architecture of the graphene hydrogel was functionalized by using lignosulfonate with diverse oxygen containing groups. Benefiting from a large specific surface area, multiple porosity and sufficient active sites, the LS-GH adsorbent exhibited ultrahigh adsorption capacity (1210 mg g(-1)) for Pb(II) removal, which was among the highest of previously reported Pb(II) adsorbents. Importantly, the free-standing and flexible LS-GH can be used as a column-packed device, providing an efficient pathway for the fast removal of Pb(II) with an ultrahigh adsorption capacity of 1308 mg g(-1) within 40 min. The high capacity LS-GH adsorbent is low cost, eco-friendly and recyclable, which could be an attractive adsorbent for the purification of wastewater on a large scale.