Potential role of Spirulina (Arthrospira) platensis biomass for removal of TiO2NPs-MG hybrid nanocomposite produced after wastewater treatment by TiO2 nanoparticles

Biosynthesis of titanium dioxide nanoparticles (TiO(2)NPs) by Sphingomonas paucimobilis B34 bacteria was successfully achieved and followed by UV-Vis spectroscopy. The nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and fourier transform infrared spectroscopy (FTIR) techniques. The biosynthesized TiO(2)NPs were spherical in shape with an average particle size of 15.6 nm. These TiO(2)NPs were used as nono-catalyst for removing of malachite green (MG) dye (at 103 mol/L) from wastewater solution. As indicated by the results, the biosynthesized TiO(2)NPs represented a capable approach for MG removal with up to 83 % efficiency. The removal process was found to follow a pseudo-first-order kinetics. Furthermore, the developed TiO(2)NPs-MG hybrid nanocomposite was efficiently removed from the medium by using Spirulina platensis cyanobacterial biomass after wastewater treatment. S. platensis biomass was able to remove up to 89.43 % of the hybrid nanocomposite by a biosorption process. The resultant water effluent, after TiO(2)NPs-MG removal, showed no toxicity towards Vigna radiate L. seedlings implying its safety for agriculture purposes. According to the obtained results, S. platensis living biomass could play a dual re-cycling role, as natural biosorbent for removing both nanoparticles and dye (TiO(2)NPs-MG hybrid nano-composite) from solution after wastewater treatment for healthier environmental management.