Iron-loaded Sphagnum moss extract residue for phosphate removal

Abstract

Sphagnum moss extract residue (SMER), obtained after pressurized hot water extraction, was modified with Fe(III) and investigated for phosphate sorption. Although moss extract contains value-added compounds, SMER is considered to be waste until suitable uses can be developed. The effect of modification conditions were investigated, i.e. different initial Fe(III) concentrations (0.024, 0.048 and 0.072 mol/L Fe) and modification pH values (5, 7 and 9). A modification pH of 5 and the highest initial Fe(III) concentration (0.072 mol/L Fe) resulted in the highest phosphate removal efficiency, and thus was selected for further study. The removal efficiency was found to decrease with increasing pH in the range of 3-9. Maximum removal efficiency (82%) for phosphate sorption was observed at pH 3 after 24 h contact time (dosage 2 g/L, initial concentration 15 mg P/L). With increased contact time, the phosphate removal efficiency improved and reached equilibrium within 48 h. The Elovich model was found to provide the best fit to the kinetic data. A capacity of 9-13 mg P/g was obtained with a 24-h contact time at pH 4. A good fit was achieved with the Redlich-Peterson equation. FTIR analysis confirmed that carboxylic acid groups were involved in the modification process. X-ray diffraction analyses showed that amorphous two-line ferrihydrite was precipitated onto SMER, which was supported by X-ray photoelectron spectroscopy analyses.

Utilization of ferric groundwater treatment residuals for inorganic-organic hybrid biosorbent preparation and its use for vanadium removal

“…3 The O1 s spectrum of raw peat presented only a single peak at 532. 5 were also found earlier by Zhang et al [34].…”

“…The Redlich-Peterson model was found to provide the best fit to the experimental data since it has the highest coefficient of determination (R 2 ) and lowest chi-squared ( values. This model has also previously been reported to provide the best fit for other iron-impregnated biomass [34,49].…”

“…Since maximum (2) vanadium removal efficiency was observed at pH 4, it was selected as the optimal sorption pH and chosen as the sorption pH for further experiments in this study. observed that phosphate sorption equilibrium was reached at about 48 hours for iron-loaded Sphagnum moss biomass, and the iron species loaded was confirmed to be two-line ferrihydrite [34].…”

“…The characteristics of the Fe-GWTR solutions are shown in [34]. The result showed that pH 5 was the optimal modification pH and exhibited the highest phosphate removal efficiency.…”

“…8, the plot goes through the origin (R 2 : 0.984), thus indicating that intra-particle diffusion is the rate-limiting step. Fe-loaded Sphagnum moss biomass and used it for phosphate removal, and the maximum capacity was around 13 mg P/g [34]. Gupta et al used iron-chitosan flakes for removal of As(III) and As(V), and the maximum capacity was 16 mg/g and 22 mg/g, respectively [56].…”