title: Sorption kinetics and leachability of heavy metal from the contaminated soil amended with immobilizing agent (humus soil and hydroxyapatite).
abstract: Release of heavy metals onto the soil as a result of agricultural and industrial activities may pose a serious threat to the environment. This study investigated the kinetics of sorption of heavy metals on the non-humus soil amended with (1:3) humus soil and 1% hydroxyapatite used for in situ immobilization and leachability of heavy metals from these soils. For this, a batch equilibrium experiment was performed to evaluate metal sorption in the presence of 0.05 M KNO(3) background electrolyte solutions. The Langmuir isotherms applied for sorption studies showed that the amount of metal sorbed on the amended soil decreased in the order of Pb(2+)>Zn(2+)>Cd(2+). The data suggested the possibility of immobilization of Pb due to sorption process and immobilization of Zn and Cd by other processes like co-precipitation and ion exchange. The sorption kinetics data showed the pseudo-second-order reaction kinetics rather than pseudo-first-order kinetics. Leachability study was performed at various pHs (ranging from 3 to 10). Leachability rate was slowest for the Pb(2+) followed by Zn(2+) and Cd(2+). Out of the metal adsorbed on the soil only 6.1-21.6% of Pb, 7.3-39% of Zn and 9.3-44.3% of Cd leached out from the amended soil.
authors.affiliation: Ecotoxicology Section, Industrial Toxicology Research Centre, Post Box No. 80, M.G. Marg, Lucknow 226001, India.
authors.forename: Pranav Kumar
authors.initials: PK
authors.lastname: Chaturvedi
authors.forename: Chandra Shekhar
authors.initials: CS
authors.lastname: Seth
authors.forename: Virendra
authors.initials: V
authors.lastname: Misra
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000327:Adsorption; D002104:Cadmium / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D007700:Kinetics; D007854:Lead / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry; D012987:Soil; D012989:Soil Pollutants; D018505:Waste Management / Q000379:methods; D015032:Zinc / Q000737:chemistry*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D012972:Sodium Hydroxide; D017886:Durapatite; D015032:Zinc; D019342:Acetic Acid