Preparation of sodium alginate-carboxymethyl cellulose-graphene oxide composite aerogel for adsorption of Pb(II) ion

Exploiting adsorbents with excellent adsorption activity, good durability and environment friendly is still the core focus of water pollution treatment. Herein, in this study, sodium alginate (SA), carboxymethyl cellulose (CMC), and graphene oxide (GO) were used as raw materials to frame a composite aerogel (SA-CMC-GO) with a 3D network structure by a sol-gel and freeze-drying method. The functional group structure and microstructure of SA-CMC-GO composite aerogel were tested and analyzed by SEM, FTIR and XRD. Various parameters affecting the removal of Pb²⁺ such as pH, temperature and contact time were optimized by using a series of batch adsorption experiments. The results showed that the adsorption amount of Pb²⁺ by the composite aerogel increased with the increase of pH at 2-5. The adsorption process was a spontaneous exothermic process and the experimental data of the adsorption process were more fitted to Langmuir isotherm, the theoretical maximum adsorption capacity of Pb²⁺ on SA-CMC-GO composite aerogel was 272.5 mg·g⁻¹. Adsorption kinetics studies indicated the adsorption of Pb²⁺ by the SA-CMC-GO composite aerogel shown rapid uptake rates and reached equilibrium within 60 min. The pseudo-second-order kinetic model coincided with the adsorption behavior of the composite aerogel. Furthermore, the composite aerogel exhibited better reusability for five adsorption and desorption cycles with highly adsorption properties. The results imply that the new SA-CMC-GO composite aerogel could be potentially applied as an effective and rapid adsorbent for Pb²⁺ removal from aqueous solutions.