Exploring the nanobiohybrids of nanodiamonds-functionalized MoAlB@MBene and microalgae synergistic potential for sustainable pharmaceutical removal

Nanobiohybrid systems combine nanomaterials and biological, creating synergistic platforms for diverse applications. We successfully developed MoAlB@MBene using HCl/H 2 O 2 mixture, transforming the densely packed nanolaminar MoAlB MAB phase into an expanded multilayered MBene’ structure, featuring open slit-shaped pores. EDS and XRF analysis suggested that the voids between the Mo-B layers were due to the removal of approximately one aluminum layer. The etching of the MAB phase also caused a transition in the zeta potential from 1.11 to −3.35. Such characteristics suggest a potential for MBene’ surface functionalization. SEM and EDS confirmed that functionalization with 1.0 wt% fluorescent nanodiamonds (FND) was optimal, and guaranteed uniform distribution of the FND. Such enrichment also ensured favorable optical properties, including fluorescence in the orange/red region and a reduced direct band gap value by incorporating FND (from 1.32 eV to 0.54 eV). Functionalization with FND also mitigated the ecotoxicological properties of MoAlB@MBene. We observed sustained proliferation even at a concentration of 500 mg L −1 of the nanocomposite, with toxicity plateauing after 48 h of incubation. Optimization of encapsulation with sodium alginate suggested the best concentration (1.5 wt%) and cross-linking time (10 min), allowing for structural integrity, sphericality, and rapid microalgae growth. The fluorescent nanocomposite within encapsulated microalgae improved the decomposition rate of tetracycline (18 vs 45 %) and doxycycline (14 vs 48 %), achieving almost threefold enhancement within 24 h. Furthermore, it positively influenced microalgae growth, counteracting pharmaceuticals toxic effects. Altogether, these findings provide insights into developing and maintaining nanobiohybrid systems, incorporating fluorescent nanocomposite and microalgae, combining the knowledge from environmental protection and materials science. • Developed MoAlB@MBene was functionalized with fluorescent nanodiamonds (FND) • 1.0 wt% of FND was revealed as optimal • Functionalization reduced the direct band gap from 1.32 eV to 0.54 eV • Optimal encapsulation conditions: 1.5 wt% sodium alginate and 10 min cross-linking • Enhanced microalgae growth and pharmaceutical decomposition was noticed