Synthesis, characterization and performance of high energy ball milled meso-scale zero valent iron in Fenton reaction

• Published in: Journal of environmental management 2016-10, Vol.181, p.847-855
• Main Authors: Ambika, Selvaraj, Devasena, M., Nambi, Indumathi Manivannan
• Format: Article
• Language: English
• Subjects: Ball milling; Buffered and unbuffered system; Buffers; Catalysts; Chemical synthesis; Experiments; Fenton’s oxidation; Ferryl ion; High energy ball mill; Hydrogen Peroxide - chemistry; Hydrogen-Ion Concentration; Iron; Iron - chemistry; Meso zero valent iron; Nanoparticles - chemistry; Oxidants - chemistry; Oxidation-Reduction; Particle Size; Phenol - chemistry; Phenol - isolation & purification; Temperature; Water Pollutants, Chemical - chemistry
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2016.06.054

Understanding contaminant degradation by different sized zero valent iron (ZVI) particles is one important aspect in addressing the long-term stability of these particles in field studies. In this study, meso zero valent iron (mZVI) particles were synthesised in a milling time of 10 h using ball milling technique. The efficacy of mZVI particles for removal of phenol was quantitatively evaluated in comparison with coarse zero valent iron (cZVI) and nano zero valent iron (nZVI) particles. Phenol degradation experiments were carried out in sacrificial batch mode at room temperature independently with cZVI, nZVI and mZVI under varied pH conditions of 3, 4, 6, 7, 8 and 10. Batch experiments substantiating the reactivity of mZVI under unbuffered pH system were also carried out and compared with buffered and poorly buffered pH systems. mZVI particles showed consistent phenol degradation at circum-neutral pH with efficiency of 44%, 67%, and 89% in a span of 5, 10 and 20 min respectively. The dissolved iron species and residual iron formation were also measured as a function of pH. Unbuffered systems at circum-neutral pH produced less residual iron when compared to buffered and poorly buffered systems. At this pH, oxidation of Fe2+ produced a different oxidant Ferryl ion, which was found to effectively participate in phenol degradation. [Display omitted] •Use of High energy ball milled meso ZVI (mZVI) in Fenton reaction was studied.•Iron speciation and oxidant analysis speculate Ferryl species at circumneutral pH.•Dissolved Fe ions easily migrate across mZVI’s oxide film than nano ZVI.•Unbuffered systems showed efficient degradation with less residual iron and sludge.•In-situ/ex-situ treatment using scarp ZVI without buffer/stabilizer is possible.