title: Removal of some metal ions by activated carbon prepared from Phaseolus aureus hulls.
abstract: Removal of lead [Pb(II)], zinc [Zn(II)], copper [Cu(II)], and cadmium [Cd(II)] from aqueous solutions using activated carbon prepared from Phaseolus aureus hulls (ACPAH), an agricultural waste was studied. The influence of various parameters such as effect of pH, contact time, adsorbent dose, and initial concentration of metal ions on the removal was evaluated by batch method. The removal of metal ions by ACPAH was pH dependent and the optimum pH values were 7.0, 8.0, 7.0 and 6.0 for Cu(II), Cd(II), Zn(II), and Pb(II), respectively. The sorption isotherms were studied using Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin isotherm models. The maximum adsorption capacity values of ACPAH for metal ions were 21.8 mg g(-1) for Pb(II), 21.2 mg g(-1) for Zn(II), 19.5 mg g(-1) for Cu(II), and 15.7 mg g(-1) for Cd(II). The experiments demonstrated that the removal of metal ions followed the pseudo-second-order kinetic model. Desorption experiments were carried out using HCl solution with a view to regenerate the spent adsorbent and to recover the adsorbed metal ions.
authors.affiliation: Analytical and Environmental Chemistry Division, Department of Chemistry, Sri Venkateswara University, Tirupati 517 502, India.
authors.forename: M Madhava
authors.initials: MM
authors.lastname: Rao
authors.forename: D K
authors.initials: DK
authors.lastname: Ramana
authors.forename: K
authors.initials: K
authors.lastname: Seshaiah
authors.forename: M C
authors.initials: MC
authors.lastname: Wang
authors.forename: S W Chang
authors.initials: SW
authors.lastname: Chien
mesh_terms: D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D015386:Hazardous Substances / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000302:isolation & purification*; D027805:Phaseolus / Q000737:chemistry*; D012996:Solutions; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D015386:Hazardous Substances; D008670:Metals; D012996:Solutions; D014874:Water Pollutants, Chemical; D002606:Charcoal