%0 Journal Article
%T Investigation of Hexavalent Chromium Reduction in Strong Saline and Acidic Nitro-Phosphate Solutions
%A Deniz Avsar
%A Niels H£żjmark Andersen
%A Dag £żistein Eriksen
%A Jon Petter Omtvedt
%J Journal of Analytical Sciences, Methods and Instrumentation
%P 1-13
%@ 2164-2753
%D 2024
%I Scientific Research Publishing
%R 10.4236/jasmi.2024.141001
%X Phosphorus fertilizers from less pure
sedimentary sources become increasingly important, due to depletion of
phosphorus from igneous rock of high quality. Consequently, robust methods with
potential to remove various types of hazardous elements are required. Among
such impurities, hexavalent chromium (Cr(VI)) is very likely to become a future
challenge. Different industrial ways to treat phosphate rock are currently
being practised, and we have here studied how chromium behaves when using the
nitro-phosphate process.<span style=\"font-family:;\" \"=\"\"> </span><span style=\"font-family:;\" \"=\"\">The
reduction mechanism of Cr</span><span style=\"font-family:;\" \"=\"\"> </span><span style=\"font-family:;\" \"=\"\">(VI) in
nitric acid and phosphoric acid solutions was investigated by measuring redox
potential and UV-VIS spectra. The results show that Cr</span><span style=\"font-family:;\" \"=\"\"> </span><span style=\"font-family:;\" \"=\"\">(VI) is not stable in strong
nitric acid solu</span><span style=\"font-family:;\" \"=\"\">tions.
Reduction of Cr</span><span style=\"font-family:;\" \"=\"\"> </span><span style=\"font-family:;\" \"=\"\">(VI)
species decreased with decreasing temperature, NO<sub>2</sub> concentration,
ionic strength and absence of light.</span><span style=\"font-family:;\" \"=\"\"> </span><span style=\"font-family:;\" \"=\"\">These findings support</span><span style=\"font-family:;\" \"=\"\"> the </span><span style=\"font-family:;\" \"=\"\">proposed
reduction reaction:<img src=\"Edit_141cf44c-eb3c-4764-92b1-963c66f98b75.png\" width=\"200\" height=\"25\" alt=\"\" /><img src=\"Edit_fee0e3fb-7926-4307-8229-fb5906ae873b.png\" width=\"170\" height=\"25\" alt=\"\" /></span><span><span style=\"font-family:;\" \"=\"\">The reduction rate was observed</span><span style=\"font-family:;\" \"=\"\"> </span><span style=\"font-family:;\" \"=\"\">proportional to the nitric acid decomposition:</span><span style=\"font-family:;\" \"=\"\"><br />
</span><span style=\"font-family:;\" \"=\"\"><img src=\"Edit_d1eeb842-41a3-497b-80d7-d5ab043dd01f.png\" width=\"300\" height=\"25\" alt=\"\" />.</span></span>
%K Nitro-Phosphate Fertilizers
%K Chromium (VI) Reduction
%K Chromium Speciation
%K Ultraviolet-Visible Spectroscopy
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=131168