Voltammetric methods for the speciation of dissolved iron and determination of Fe-containing nanoparticles in mine-water discharge

Abstract

A voltammetric procedure for the determination of total, dissolved, solid phase and nanoparticulate Fe in polluted mine-waters has been developed. Mine-water samples were collected from abandoned mine sites in the UK, which have been designated by the UK Coal Authority for remediation research and for routine monitoring of mine-water quality. Monthly samples were taken over the period March, 2006 to April, 2007 from six different sites in North East England. The samples were analysed directly using differential pulse voltammetry at gold electrodes: separate peaks due to unhydrolysed and hydrolysed Fe aquo ions could be assigned and quantified. The results show that our analysis provides data for total dissolved iron of comparable analytical quality to the established mine-water analysis techniques based on inductively-coupled plasma-optical emission spectroscopy. Further, the difference between differential pulse voltammetry data in acidified and unacidified samples allows quantitation of the Fe-containing solid phase and nanoparticulate Fe oxyhydroxide phases. If samples were prefiltered, then these measurements also allowed us to determine the fraction of Fe present in nanoparticles <450 nm diameter. Finally, steady-state voltammetry at Pt microelectrodes was used to obtain the ratio of Fe(II) and Fe(III) redox states in the soluble Fe fraction.

GSH-doped GQDs using citric acid rich-lime oil extract for highly selective and sensitive determination and discrimination of Fe3+ and Fe2+ in the presence of H2O2 by a fluorescence “turn-off” sensor

“…In addition, the measurement of iron concentration in water samples is also crucial for environmental safety. 10 Currently, several analytical techniques for determination of Fe 2+ and Fe 3+ ions have been applied including solid phase extraction, 11 ber-optic chemosensor, 12 voltammetric methods, 13 high performance liquid chromatography, 14 capillary electrophoresis, 15 inductively coupled plasma mass spectrometry, 16 ow injection analysis 17 and chemiluminescence. 18 Although these techniques are highly sensitive and selective, they require tedious sample preparation and preconcentration procedures, expensive instruments, and professional personnel.…”

Logic operation for differentiation and speciation of Fe3+ and Fe2+ based on two‐dimensional metal–organic frameworks with tunable emissions

“…The pH-dependent luminescence spectra were investigated by immersing the powders of LMOFs 1-3 under a series of pH (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) conditions for 12 h. The luminescent intensities and PXRD patterns of the compounds after soaking within the pH range of 3-10 were almost unchanged, indicating the high acid-base stability of LMOFs 1-3 ( Figures S6 and S7). The negligible changes of the time-dependent luminescence for LMOFs 1-3 even after 150 min reveal that LMOFs 1-3 have high dispersibility and optical stability in water ( Figure S8).…”

“…In fact, numerous works have successfully reported the sensing of Fe 3+ via voltammetry techniques, [5] high-performance liquid chromatography (HPLC), [6] fiber-optical chemosensing, [7] inductively coupled plasma mass spectrometry (ICP-MS), [8] electrophoresis methods, [9] and flow injection analysis. [10] Nevertheless, the majority of these techniques require complicated sample pretreatments and time-consuming procedures and are limited by the weak selectivity for Fe 2+ /Fe 3+ speciation.…”

Sensitive Quantification of Fe(III) in Food Samples at Screen Printed Carbon Electrode Modified with Graphene and Piroxicam by Catalytic Adsorptive Voltammetry

“…Also, iron has an important role in biological systems, industries, and medicines [2,3]. However, it can be considered as a water contaminant at high concentration [3,4]. Additional amounts of iron than standard level induces many diseases, poisoning, and even death [5].…”