The Potential of Powdered Rock Phosphates of Some Iranian Mines for Removal of Phosphate Ions from Aqueous Solutions

Document Type : Research Paper

Authors

Soil Science department, College of Agriculture, Yasuj university, Yasuj, Iran.

Abstract

Powdered rock phosphate may have the potential of soluble phosphate sorption because its particles are small. Phosphorus (P) sorption-desorption behavior and sorption kinetics were studied on four different finely powdered phosphate rocks (PPR), from Esfordi, Chadormalu and Yasuj. Sorption isotherms were evaluated by equilibrating 1 g PPR with 20 ml CaCl2- 0.01 M containing 10, 50, 100, 200, 400, 600, 800 and 1000 mg P L-1, as KH2PO4 in duplicates. Consequently, P release was studied by equilibrating the samples with 20 ml 0.01 M CaCl2. FTIR analysis was conducted on the blank samples, and those equilibrated with 1000 mg P L-1. Kinetics of phosphate sorption on PPRs was evaluated with two initial P concentrations (50 and 100 mg P L-1) and contact times of 1, 2, 4, 8, 16, 24, and 48 h with 0.01 M CaCl2 as the background solution in duplicate. Results showed that the least P sorption was around 150, and the maximum P sorption was 10000-12000 mg kg-1 PPRs. The highest P release was around 15% of sorbed P, and releasable P was reduced to 2-3% of sorbrd P with the increase of P sorption. P sorption data showed a good fit with Freundlich and Langmuir equations. The kinetic of P sorption showed a fast reaction, that rapidly diminished soluble P. Results of the present study suggest that PPRs could reduce soluble P, which is better to be considered at different usage of PPR such as incorporation with organic wastes and its biosolubilization.

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Iranian Journal of Soil and Water Research

Articles in Press, Accepted Manuscript
Available Online from 20 April 2024

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