THE SEDIMENTATION BEHAVIOURS OF AlPO4 AND Fe3(PO4)2 PRECIPITATES IN SOLUTIONS OF SODIUM CARBOXYMETHYLCELLULOSE AT DIFFERENT TEMPERATURES
AbstractTo evaluate the sedimentation of aluminium phosphate [AlPO4] and ferrous phosphate [Fe3(PO4)2] precipitates in sodium carboxymethylcellulose (Na-CMC) biopolymer at different temperatures, batch-wise precipitation and sedimentation tests of AlPO4 and Fe3(PO4)2 in solutions of Na-CMC were carried out at temperatures of 30, 40 and 50oC. The objective was to determine On-set Sedimentation Rate (OSR) and Sedimentation Volume Ratio (SVR) of the metal phosphates. Fixed volume of Na-CMC at different concentrations was mixed with constant volume and known concentration of phosphate ion precursor (disodium hydrogen phosphate solution) in a sedimentation measurement apparatus - PreSed Meter. The resulting solution was mixed separately with constant volume and known concentration of either aluminium ion or iron (II) ion precursor (either aluminium chloride or ferrous chloride solution). The settling of the precipitate so formed was monitored and recorded. Blank sedimentation tests, without Na-CMC, were also run. For every measurement, On-set Sedimentation Rate (OSR) and Sedimentation Volume Ratio (SVR) of the precipitates were computed. It was observed that in the absence of Na-CMC, AlPO4 precipitate readily dissolved into the medium immediately after stirring. Also, in the absence of Na-CMC, OSR and SVR of Fe3(PO4)2 precipitate increased directly with increased temperatures. The test results also indicated that AlPO4 precipitate suspension was poorly influenced by the biopolymer. Poor correlations in OSR (0.50 ≤ R2 ≥ 0.05) and SVR (0.49 ≤ R2 ≥ 0.005) indicating non-dependence with Na-CMC concentration, implying no chemical interactions with Na-CMC, were described for AlPO4 suspension at all temperatures investigated. For Fe3(PO4)2 suspension, good correlations in OSR (R2 = 0.94) and SVR (R2 = 0.93) indicating dependence with Na-CMC concentration, implying chemical interaction with Na-CMC, were obtained at high temperature (50oC). The observations imply that Na-CMC would be good stabilizing agent for drug formulations containing AlPO4. However, suspension of Fe3(PO4)2 in Na-CMC need not be stored in high temperature conditions.
How to Cite
Amadi, K. G. ., & Iboroma, D. S. . (2022). THE SEDIMENTATION BEHAVIOURS OF AlPO4 AND Fe3(PO4)2 PRECIPITATES IN SOLUTIONS OF SODIUM CARBOXYMETHYLCELLULOSE AT DIFFERENT TEMPERATURES . Journal of Chemical Society of Nigeria, 47(3). https://doi.org/10.46602/jcsn.v67i3.752