Green zero-valent iron nanoparticles from Cistus ladanifer by-products for glyphosate remediation in water and soil.

Food and agricultural sectors produce large quantities of waste that present high potential for valorization. Cistus ladanifer L., used in the perfume and essential oil industries, produces post-distillation residues rich in phenolic compounds (PCs). These residues can be exploited for the green synthesis of nano zero-valent iron (nZVI), widely studied for environmental remediation. The aim of this study was to develop green synthesized nZVI using extracts from Cistus ladanifer post-distillation leaves (CLL) and stems (CLS) as reducing agents, to be further used for the remediation of waters and soils contaminated with a prevalent pesticide, glyphosate (Glyph). nZVIs were characterized and compared with those produced by the chemical method. Twelve compounds were identified in the extracts by liquid chromatography-mass spectrometry (LC-MS). Scanning electron microscopy (SEM) revealed spherical nZVIs (sizes from 79.0 to 94.8 nm). The elemental composition, obtained by Energy-dispersive X-ray spectroscopy (EDS), demonstrated mainly carbon (41.9-48.7%), oxygen (32.6-41.0%), and iron (14.4-16.6%). Fourier-transform infrared spectroscopy (FTIR) showed the peaks corresponding to the PCs present in nZVI. In remediation studies, nZVI displayed the ability to adsorb Glyph, greatly limiting its availability in water and soil. Additionally, all nZVI showed no toxicity towards MRC-5 and U87 cell lines. To evaluate the greenness of PCs extraction and nZVI synthesis, several green analytical chemistry methods were employed. Overall, C. ladanifer by-products were used to sustainably synthesize nZVI for Glyph remediation. The use of CLL and CLS residues represents a low-cost, eco-friendly strategy, offering promising potential for Glyph removal and advancing sustainable nanoremediation approaches.