Green synthesis of novel titanomagnetite nanoparticles for oil spill cleanup

Abstract

Crude oil spills that exist in surface water are a serious threat at the worldwide level to the ecosystem and marine life in both short and long terms. Thus, environmentalists along with many investigators over the last few decades have developed many physical/mechanical, chemical, and biological methods for the effective removal and recovery of oil from water resources. However, most of those methods are either costly, ineffective, or rely heavily on utilizing toxic materials. Herein, we have developed a new protocol for the green synthesis of nanoparticles of titanomagnetite (NTM) at various conditions (i.e., initial concentrations of iron precursor and temperatures). The properties of the produced nanoparticles, such as surface area, size, crystallinity, surface structure and hydrophobicity were described by an array of characterization methods such as BET, XRD XPS, HRTEM, SEM, and contact angle measurements, to optimize the synthesis conditions. The optimal nanoparticles were used as sorbents to remove crude oil spills from water, following our modified ASTM protocol. To observe the dominant mechanisms involved in sorption of crude oil, the optimized nanoparticles were utilized to remove a cationic dye, exemplified by methylene blue (MB), using batch adsorption mode. The achieved results showed a successful synthesis of 27 batches of NTM nanoparticles at different levels of temperatures and concentrations of iron precursor. The application of the experimental design method showed a significant role for both factors in the formed nanoparticles and the great possibility of pertaining high surface area material at mild conditions. The optimal nanoparticles, compared with magnetite and other plenty sorbents, showed an outstanding performance toward removal of crude oil spills (uptake 38 ± 2 g crude oil/g NTM) and MB (uptake 36 mg MB/g). The spent NTM was completely regenerated and maintained more than 95% removal after three successive regeneration cycles, without impacting their surface chemistry. Our optimized nanoparticles were fabricated at room temperature following easily scaled technique, and then successfully applied for treatment of real heavy oil spills in contrast to many other studies that used oil models. The obtained findings also confirm that our fabricated nanoparticles can be implemented as part of an attractive method for low-cost and effective oil spill cleanup, instead of utilizing massive dosages from booms or skims via the employment of other mechanical techniques.