Kinetic and mechanism studies of the adsorption of lead onto waste cow bone powder (WCBP) surfaces.
This study examines the adsorption isotherms, kinetics and mechanisms of Pb²(+) sorption onto waste cow bone powder (WCBP) surfaces. The concentrations of Pb²(+) in the study range from 10 to 90 mg/L. Although the sorption data follow the Langmuir and Freundlich isotherm, a detailed examination reveals that surface sorption or complexation and co-precipitation are the most important mechanisms, along with possibly ion exchange and solid diffusion also contributing to the overall sorption process. The co-precipitation of Pb²(+) with the calcium hydroxyapatite (Ca-HAP) is implied by significant changes in Ca²(+) and PO₄³⁻ concentrations during the metal sorption processes. The Pb²(+) sorption onto the WCBP surface by metal complexation with surface functional groups such as ≡ POH. The major metal surface species are likely to be ≡ POPb(+). The sorption isotherm results indicated that Pb²(+) sorption onto the Langmuir and Freundlich constant q(max) and K( F ) is 9.52 and 8.18 mg g⁻¹, respectively. Sorption kinetics results indicated that Pb²(+) sorption onto WCBP was pseudo-second-order rate constants K₂ was 1.12 g mg⁻¹ h⁻¹. The main mechanism is adsorption or surface complexation (≡POPb(+): 61.6%), co-precipitation or ion exchange [Ca₃(.)₉₃ Pb₁(.)₀₇ (PO₄)₃ (OH): 21.4%] and other precipitation [Pb 50 mg L⁻¹ and natural pH: 17%). Sorption isotherms showed that WCBP has a much higher Pb²(+) removal rate in an aqueous solution; the greater capability of WCBP to remove aqueous Pb²(+) indicates its potential as another promising way to remediate Pb²(+)-contaminated media.
Korea University, Seoul, Korea.
Jihoon
J
Cha
Mingcan
M
Cui
Min
M
Jang
Sang-Hyun
SH
Cho
Deok Hyun
DH
Moon
Jeehyeong
J
Khim
D000327:Adsorption; D000818:Animals; D001031:Apatites / Q000737:chemistry*; D001842:Bone and Bones / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D002417:Cattle; D004785:Environmental Pollutants / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007700:Kinetics; D007854:Lead / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D013499:Surface Properties
D001031:Apatites; D004785:Environmental Pollutants; D010710:Phosphates; D007854:Lead; D002118:Calcium