Hybrid aerogels of sodium alginate/graphene oxide as efficient adsorbents for wastewater treatment

In this work, hybrid aerogel beads of sodium alginate (SA) and graphene oxide (GO) were synthesized by the external gelation method, dried by supercritical CO2, and applied for tartrazine removal from aqueous media. The effects of drying time, calcium chloride (CaCl2) and GO content on the aerogel properties were first investigated. The SA and SA-GO aerogel beads presented a homogeneous size distribution with Polydispersity Index (PDI) lower than 10% and volumetric shrinkages and compressive strengths up to 25%. The maximum tartrazine adsorption capacity of 420.36 mg/g achieved by SA-GO aerogel was 3-fold higher than for pure SA aerogel beads (129.64 mg/g). The adsorption isotherms described properly the experimental tartrazine adsorption and indicated that the absorption process was governed by the mass transfer mechanism. The results suggest that the prepared aerogels are promising adsorbents materials for wastewater treatment. [Display omitted] •Pure alginate and hybrid alginate-graphene oxide aerogel beads of homogeneous particle size distribution were synthetized•Young's modulus of 3.935 MPa on 1% of sodium alginate-graphene oxide aerogel.•Maximum uptake capacity of tartrazine for hybrid aerogels of 420.36 mg/g.•Adsorption processes achieves equilibrium in 30 min.•Removal of more than 90% tartrazine from the hybrid aerogels in 20 min.