Sustainable approach for adsorptive removal of cationic and anionic dyes by Titanium Oxide nanoparticles synthesized biogenically using algal extract of Spirulina

Abstract Worldwide, dyes are significant pollutants present in water because of their huge consumption for industrial purposes. These dyes as pollutants cause serious health issues in human beings and also cause the loss of aquatic biodiversity. So, remediation of pollutants like dyes from wastewater is the need of the hour. In the present study, we greenly synthesized Spirulina-mediated titanium oxide nanoparticles (STONPs) for the adsorptive remediation of cationic malachite green (MG) and anionic methyl orange (MO) dyes. The characterization of STONPs was performed by X-Ray Diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FESEM) with Energy Dispersive X-ray analysis (EDX), Zeta Potential & Particle size analyzer (PSA), Raman spectroscopy, and Ultraviolet-visible spectroscopy (UV-VIS). The various parameter effects like pH, nano-adsorbent dose, the concentration of dye, contact time, and temperature were also examined. Adsorption isotherms like Freundlich, Langmuir, & Temkin, and Kinetics models like Pseudo 1st and Pseudo 2nd order, Elovich Model, intraparticle diffusion model (IPDM), and Thermodynamic model were applied for a stronger interpretation. The qmax obtained from the Langmuir adsorption model was 272.4795 mg/g and 209.6436 mg/g for MO and MG correspondingly. The regeneration study of synthesized nanomaterials up to five cycles was also done. We found that greenly synthesized STONPs have great potential for adsorptive remediation for both MG and MO dyes.