Effective enhancement of copper selective removal from sodium alginate-based gel adsorbent by dual construction of slit-shaped structure and internal channel

The Cu(II) treatment in water environment by adsorption has become a major strategy for water pollution control and water resource protection. In view of the planar configuration characteristics of Cu(II) complex, the construction and optimization of adsorbent's internal structure to achieve improved adsorption performance is still a problem worth exploring. Herein, polyvinyl alcohol (PVA) is introduced into graphene oxide/sodium alginate (GO/SA) gel system to obtain PVA/GO/SA gel material, which not only achieves the construction of slit-shaped structure by self-interlayer stacking for GO nanosheets and its cross-linking with SA, but effectively promotes formation of high cross-linking density internal channels by the introduction of PVA, thus achieving the efficacious and selective Cu(II) removal. Maximum adsorption capacity for PVA/GO/SA can reach 96.81 mg/g, and it also shows excellent selective removal rates in various real water environments. Molecular dynamics simulation is used to explore the key roles of each component of PVA/GO/SA on gel formation, slit-shaped structure and internal channel construction, and adsorption reaction activity, and to validate the efficacy components and adsorption mechanism of PVA/GO/SA in Cu(II) adsorption based on density-functional theory (DFT) and simulation calculations. Our study can provide a new structural design idea for the efficient selective Cu(II) adsorption materials.