Removal Behavior of Pb2+, Cd2+, Zn2+ from wastewater of lead, zinc mining – Cho Don, Bac Kan by halloysite clay

Halloysite from Thach Khoan, Phu Tho province showed nanotube structure with a chemical formula Al2Si2O5(OH)4.2H2O when fully hydrated and Al2Si2O5(OH)4 when dehydrated, specific surface areas are 15.7434 and 22.0211 m2/g. Halloysite was used to study on adsorption behaviour of Pb2+, Cd2+, Zn2+ (M2+) ions. The effect of factors on the M2+ adsorption efficiency was investigated. The adsorption efficiency of Pb2+, Cd2+, Zn2+ obtained 90.75; 73.75 and 67.09 % respectively under the suitable condition: halloysite mass of 0.7 g/50 mL solution, initial concentration of 40 mg/L M2+, pH for Pb2+, Cd2+, Zn2+ = 5.31; 6.2; 5.6 espectively, contact time of 80 minutes (for Pb2+, Cd2+) and 100 minutes (for Zn2+) at room temperature (30 oC). Adsorption isotherm curves were studied based on Langmuir and Freundlich models. The kinetic of the adsorption process was investigated following the first-order-pseudo and second-order-pseudo models. Removal efficiency of Pb2+, Cd2+ and Zn2+ from the wastewater of lead, zinc mining – Cho Don, Bac Kan was 99,59 %; 92,08 % và 99,46 %, respectively.