Optimization of a simple continuous system for the preparation of zero-valent iron nanoparticles coated with flaxseed gum: Effect of groundwater quality on the aggregation

• Published in: Environmental technology & innovation Vol. 30; p. 103119
• Main Authors: Izadi, Neman, Sangani, Mohammad Mahdi Masoumi, Yavari, Mohammad Ali, Baghdadi, Majid
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2023
• Subjects: Aggregation; Continues synthesis; Flaxseed gum; Green synthesis; nZVI; Stabilization; Flaxseed gum; Aggregation; Continues synthesis; Green synthesis; nZVI; Stabilization
• DOI: 10.1016/j.eti.2023.103119
• ISSN: 2352-1864

In recent years, in-situ removal of pollutants by iron nanoparticles due to their non-toxicity, abundance, and low cost of production, has been considered. In this research, a novel continuous synthesis system was used for the synthesis of nanoscale zero-valent iron (nZVI). For the stabilization of nZVI, flaxseed gum (FS) as a green, non-toxic, and cost-effective coating was used. Dynamic Light Scattering (DLS), Field Emission-Scanning Electron Microscopy (FE-SEM), Energy-dispersive X-ray Spectroscopy (EDX), and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterize the synthesized nanoparticles. The stability of synthesized nanoparticles under various conditions (including FS/Fe mass ratio, flow rate, and needle size) was measured by a DR5000 spectrophotometer at the wavelength of 680 nm. Also, the nanoparticles stabilized with flaxseed gum were compared with nanoparticles stabilized with other coatings. The characterization, identification, and stability tests showed that the flaxseed gum was suitable for stabilization. The FS/Fe mass ratio of 1.60 was reported to achieve the best performance. The effect of different Fe concentrations with a constant coating concentration of 0.80 g L−1 was also analyzed, and it was found that the coating concentration of 0.50 g L−1 had the best stability. Furthermore, nanoparticles became more stable as the flow rate increased. The most remarkable results were obtained using synthesized nanoparticles in a continuous injection procedure with a fine-diameter needle. Moreover, the effects of alkalinity, hardness, SO4−2, and humic acid on the sedimentation of nZVI were investigated. The results showed that by increasing the alkalinity concentration and decreasing hardness, the rate of nZVI sedimentation increased. The increase in SO4−2 had no discernible effect on the sedimentation rate constants. By raising the hardness concentration, on the other hand, the sedimentation was greatly accelerated. [Display omitted] •The use of nZVI for environmental remediation is increasingly studied.•A novel continuous synthesis system was used for the synthesis of nZVI.•nZVI was coated with flaxseed gum as a green stabilizer.•The FS/Fe mass ratio of 1.6 was reported to achieve the best performance.•The continuous synthesis system of nZVI with flaxseed gum showed more stability.