Sequestration of Pb(II) onto Phosphate Modified Fibrous Prunus Dulcis Seed Shell: Kinetic, Thermodynamic, Isotherm, Desorption and Reusability

Abstract

The utilization of fibrous prunus dulcis seed shell powder (UPDSSP) and the phosphate-modified derivative (P-MPDSS) for the abstraction of Pb2+ was tested. The Fourier transform infrared (FTIR), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), energy-dispersive X-ray (EDX), and the physicochemical characterizations revealed desirable characteristics of the adsorbents for efficient Pb(II) uptake. The FTIR of UPDSSP and P-MPDSS showed several functionality groups on the adsorbents. SEM morphology revealed high porosity surface structure of both adsorbents, while BET measurements showed an increase in surface area from 5.84 m2/g to 11.32 m2/g after phosphate modification. The modified adsorbent showed higher Pb(II) uptake than UPDSSP at variations of temperature, time, pH, metal concentration, and material dosage. pH 5.0 was optimum for Pb(II) adsorption and equilibrium was reached at 90 min on UPDSSP and P-MPDSS. The Freundlich isotherm presented the best fit (R2 > 0.991) than the Langmuir and Dubinin-Raduskkevich models. The pseudo-second-order gave the best fit (R2 > 0.971) than the pseudo-first-order and intraparticle diffusion kinetic equations. Thermodynamics showed endothermic, spontaneous, and physical adsorption of Pb(II) ions onto the adsorbents. The adsorbents showed good potentials for regeneration and reuse. The results revealed UPDSSP and P-MPDSS as viable materials for the decontamination of Pb polluted water.

Keywords

• prunus dulcis
• adsorption
• physisorption
• chemisorption
• adsorbent
• metals