Silver Concentration in Water Filtered by SIPP
The present part of the study is a continuous investigation on the performance of SIPP in removing pathogenic organisms from contaminated water sources. The preliminary experimental studies were conducted in our laboratory by Momba and co-authors [29,30]. During this initial study, the authors conducted a series of analytical and mechanical characterization tests on the SIPP, which included the
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XRF analysis that confirmed the presence of Ag, the break strength and the porosity of the filter. These authors found that the silver leached from the SIPP pot was at a level of between 0.5 and 0.6 mg/L [29], higher than the WHO recommendation of 0.1 mg/L [31]. The Ag elution was greatest in the early stages (within the first 5 L) but appeared to begin to stabilize by 10 L.
For the present study, the SIPP filter was soaked in 20 L deionised water overnight prior to use. The concentration of the silver in the filtered water was monitored at one-hour intervals over a three-hour period to determine the Ag elution by the SIPP after filtering a total volume of 305 L. The first, second and third filter runs were performed with deionised water, groundwater and surface water, respectively. The Spectro Acros ICP spectrometer (Spectro, RSA) was used to detect and determine the concentration of silver in each water sample.