The capacity of an adsorbent to bind and remove dye from solution greatly depends on the type of
functionalization present on the nanoparticles surface, and its interaction with the dye molecules.
Within this study, nitrogenous silane nanoparticles were hydrothermally synthesized resulting in the
formation of rapid and highly efficient adsorbents for concentrated mixed dyes. The amorphous
silane nanoparticles exhibited a monolayer based mechanism of mixed dye adsorption with removal
capacities between 416.67 – 714.29 mg/ g of adsorbent. Dye removal was predominantly due to the
electrostatic attraction between the positively charged silane nanoparticles (13.22- 8.20 mV) and the
negatively charged dye molecules (-54.23 mV). Addition of H. annuus extract during synthesis
resulted in three times the surface area and 10 times increased pore volume compared to the
positive control. XPS analysis showed that silane treatments had various nitrogen containing functionalities at their surface responsible for binding dye. The weak colloidal stability of silane
particles (13.22 - 8.20 mV) was disrupted following dye binding, resulting in their rapid coagulation
and flocculation which facilitated the separation of bound dye molecules from solution. The
suitability for environmental applications using these treatments was supported by a bacterial
viability assay showing > 90% cell viability in treated dye supernatants. |
