INTERPHASE PARTITIONING OF IRON AND ALUMINUM DURING ALKALINE PROCESSING OF ARAL SEA SAPROPEL
Authors
Shakhnoza Shukhrat qizi Rashitova
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Aims: To determine how potassium hydroxide concentration, temperature, and liquid-to-solid ratio affect pH and the transfer of aluminum and iron from sapropel into the liquid phase, and to quantify retention of both elements in the residual solid under resource-efficient conditions.
Study Design: Factorial laboratory screening of three potassium hydroxide concentrations (1, 2, and 3%), six temperatures (40-90 °C), and five liquid-to-solid ratios (1:1-3:1).
Place and Duration of Study: Sapropel was collected from the dried bed of the Aral Sea, Uzbekistan, and processed at the Department of General Sciences, Asia International University, Bukhara, Uzbekistan. The experimental dates were not documented in the source record.
Methodology: Air-dried, ground sapropel was treated with aqueous potassium hydroxide under continuous mixing. The separated liquid phase was analyzed potentiometrically for pH and instrumentally for aluminum and iron. Liquid-phase transfer was calculated from the element mass in solution relative to its initial mass in the sapropel.
Results: Across all tested conditions, pH ranged from 6.53 to 10.92, aluminum transfer from 0.72 to 14.20%, and iron transfer from 2.5 to 9.7%. Aluminum mobilization increased sharply at 3% potassium hydroxide and pH above 9.3. Under the selected conditions of 2% potassium hydroxide, a liquid-to-solid ratio of 2.5:1, and 80 °C (pH 8.66), 3.19% of aluminum and 5.0% of iron entered the liquid phase; 96.81% and 95.0%, respectively, remained in the solid.
Conclusion: Moderate alkalinity preserved most aluminum- and iron-bearing mineral components while supporting humic-substance processing. The residue is therefore a plausible precursor for sorbent development, although adsorption capacity, kinetics, selectivity, and regeneration must be established directly before application.
Keywords: sapropel; potassium hydroxide; aluminum; iron; phase partitioning; solid residue; sorbent precursor; Aral Sea
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Authors
Shakhnoza Shukhrat qizi Rashitova
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References:
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