Green synthesis of recyclable iron oxide nanoparticles using Spirulina platensis microalgae for adsorptive removal of cationic and anionic dyes

Globally, organic dyes are major constituents in wastewater effluents due to their large-scale industrial applications. These persistent pollutants adversely impact the public health of different living entities. Thus, wastewater remediation has become an indispensable necessity. Herein, we greenly synthesized iron oxide nanoparticles (SP-IONPs) using Spirulina platensis microalgae to remove cationic crystal violet (CV) and anionic methyl orange (MO) dyes from their aqueous solution. The engineered sorbent was thoroughly scrutinized by different characterization techniques of FT-IR, BET surface area, SEM, EDX, TEM, VSM, UV/Vis spectroscopy, and pH(PZC) measurement. The proficiency of SP-IONPs was methodically appraised for its sorptive performance towards the target CV and MO dyes under variable technological parameters (batch scenario). Collectively, the outlined results inferred an amazing efficacy characterized to the SP-IONPs sorbent for the expulsion of relevant dyes from the aqueous media. Regarding the dynamic static sorption data, the kinetics profile was ascribed to the pseudo-second order model, whereas sorption isotherm was quantitatively dominated by the Langmuir theory with maximum sorption capacities of 256.4 mg g(-1) and 270.2 mg g(-1) for CV and MO, respectively. Thermodynamics findings conformed the endothermic nature of sorption process. Repeatability of the spent sorbent was successfully emphasized for 5 times of sorption/desorption cycles. The productive sorbent admirably sequestered CV and MO dyes from spiked tap water. The potency of SP-IONPs as color collecting material from real dyeing effluents was achieved.