Textile wastewaters are characterized by high chemical oxygen demand (COD) concentration, strong color, high pH and temperature, and low biodegradability. Conventional treatment methods are considered to be inefficient to comply with the discharge limits. Recently, nano zero-valent iron (nZVI) technology has received increasing attention of the scientific community as an emerging technology for treatment of polluted streams. Due to smaller particle size, larger surface area and higher surface reactivity of iron nanoparticles, the removal of pollutants occur very rapidly. In this work, we synthesized nZVI employing green chemistry principles in a chemical reduction reaction. Iron precursor solution (FeSO₄) was reduced by plant extracts that contain polyphenols. Plant polyphenols are known to possess strong reducing agent properties and act as effective metal chelators. The objective of this study was to characterize the green synthesized iron nanoparticles in terms of size and zeta potential parameters under various synthesis conditions (pH, precursor concentration and precursor/extract volume ratio) and compare the reactivity of the engineered nanoparticles for textile wastewater treatment. Green tea leaves-GT and Rose leaves-R were selected as the plant sources. Plant extracts were examined in terms of their Total Phenolic Content (TPC) expressed as Gallic Acid Equivalent (GAE). Rose leaves were found to possess 2062 mg/L TPC whereas, Green Tea leaves were found to have 1882 mg/L in grinded powder form. Results showed that 74% color removal along with 18% TOC removal could be achieved with 5 ppm of GT-ZVI nanoparticles synthesized at a 2/1 ratio (v/v) of precursor to extract. With the same concentration of R-ZVI nanoparticles, 78% color removal and 40% of TOC removal were observed.

Nonylphenol (NP) and octylphenol (OP) are considered as endocrine disrupting compounds and they restrict the reuse potential of wastewater. Therefore, innovative and reliable technologies are required for elimination of these compounds from waste streams. In this study, we consider use of iron nanoparticles (nZVI) (0.1 mM; 2 mM) and also a composite of nZVI/fullerene nanoparticles (aq-nC₆₀) (0.1 mM nZVI/2.5 ppm aq-nC₆₀; 2 mM nZVI/2.5 ppm aq-nC₆₀) for the removal of 25 μg/L NP and OP concentrations. The nano-composite was synthesized according to chemical reduction method and was characterized using XRD, particle size distribution and zeta potential measurements. NP and OP concentrations were quantified with a GC-MS. The results demonstrated that 0.1 mM nZVI alone resulted in 6% and 17% decrease in NP and OP concentrations, respectively. However, when the nZVI concentration was increased to 2 mM, the removal efficiency increased to 59% for NP and 32% for OP. When compared with NP, lower removal rates were achieved for OP regardless of the nZVI concentration. Although NP and OP have similar chemical structures, OP has a branched arrangement and this structure is anticipated to cause a decrease in the active adsorption sites and lower removal efficiency for OP. Highest removal was obtained with 0.1 mM nZVI/2.5 ppm aq-nC₆₀ for both NP and OP. Our results show that nZVI/aq-nC₆₀ holds a potential for elimination of NP and OP from wastewater sources.