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چکیده
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Modifiedwalnut wooden shell (MWWS) and almond wooden shell (MAWS) as novel anion ex-changers were used to remove phosphorus (P) from aqueous solution. The raw and modified agricultural wastes were characterized using total N, total P, FT-IR spectra, SEM, BET, and EXD analysis. The effect of different parameters such as pH (4 to 8), contact time (5 to 600 min), and adsorbent dosage (1 to 8 g L −1 )onP adsorption was investigated. Adsorption of P onto MWWS and MAWS was studied using the batch tech-nique with different concentration of P (5 to 200 mg L −1 ) at 25 ± 2 °C. The P adsorption isotherms were fittedwith the Freundlich and Langmuir equations. Thekandnvalues were 1.57 mg g −1 and 1.88 for MWWS and 1.91 mg g −1 and 2.24 for MAWS, respec-tively. The maximum P adsorption capacities for MWWS and MAWS were 22.73 and 14.71 mg g −1 , respectively. The desorption-regeneration experimental results indicated about 4% and 3% reductions in MWWS and MAWS P adsorption efficiency after four consecutive regeneration cycles, respectively. The data well fitted with Pseudo-second-order kinetic model (R 2 ≥0.99), indicating that chemical interactions domi-nate the P adsorption process. Incubation studies showed the rate of P release in treated soil with P-loaded modified biosorbents was higher than control. Therefore, the MWWS and MAWS can potentially be used as an excellent adsorbent in remediation of con-taminated waters by P and then recycled to soil.
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