Adsorption kinetic and thermodynamic studies of phosphate onto tantalum hydroxide.
Tantalum hydroxide exhibits the ability for the removal of phosphate from aqueous solution. The kinetic study, adsorption isotherm, thermodynamic study, desorption, and foreign anions effect were examined in batch experiments. The kinetic process was very well described by a pseudo-second-order rate model. The adsorption isotherms showed that phosphate uptake fitted with a Langmuir-type model very well, with an increase of PO4(3-) adsorption capacity from 78.5 to 97.0 mg/g when the temperature increased from 298 to 338 K. The negative values of deltaG(0) and the positive values of deltaH(0) indicated that the phosphate adsorption process was spontaneous and endothermic naturally. While the deltaS(0) values obtained were positive, indicating an increase in randomness at the solid-liquid interface during the adsorption. Foreign anions tests showed that the presence of competitive ions cause minimal interference with the adsorption of phosphate on tantalum hydroxide.
School of Chemistry and Material Science, Liaoning Shihua University, Num 1, West Dandong Road, Wanghua District, Fushun 113001, PR China.
Shi-Hua
SH
Yu
Xiao-Le
XL
Dong
Hong
H
Gong
Heng
H
Jiang
Zhi-Gang
ZG
Liu
D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010710:Phosphates / Q000737:chemistry*; D013635:Tantalum / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
D010710:Phosphates; D013635:Tantalum