Sodium alginate/graphene oxide aerogel with enhanced strength–toughness and its heavy metal adsorption study

Ordered porous sodium alginate/graphene oxide (SAGO) aerogel was fabricated by in situ crosslinking and freeze-drying method. GO, as reinforcing filler, can be easily incorporated with SA matrix by self-assembly via hydrogen bonding interaction. Compared with pure SA aerogel, the as-prepared SAGO exhibited excellent mechanical strength and elasticity, and the compression strength of SAGO can reach up to 324 kPa and remain 249 kPa after five compression cycles when 4 wt% GO was added, which were considered significant improvements. SEM result presents that the addition of GO obviously improves the porous structures of aerogel, which is beneficial for the enhancement of strength–toughness and adsorbability. As a consequence, the adsorption process of SAGO is better described by pseudo-second-order kinetic model and Langmuir isotherm, with maximum monolayer adsorption capacities of 98.0 mg/g for Cu2+ and 267.4 mg/g for Pb2+, which are extremely high adsorption capacities for metal ions and show far more promise for application in sewage treatment.