| Constructed wetlands are widely used as sewage ecological treatment technology for the treatment of domestic sewage, industrial wastewater, mining and oil exploitation wastewater. In this research, we evaluate Pb2+ adsorption performance of wetlands substrates in wastewater containing lead and screened out suitable wetlands substrates to treat special heavy metal wastewater, absorption of lead on the substrates of zeolite, gravel, magnetite, haydite, quartz sand and pearlite were evaluated. The results showed that the zeolite, magnetic iron ore and gravel had good removal effects：the removal rate of zeolite and magnetic iron ore were up to 99% and the removal rate of gravel was above 92% at Pb2+ concentration of 200 mg·L-1. The Pb2+ adsorption abilities followed as：zeolite>magnetite>gravel>quartz sand>perlite> haydite. Pb2+ concentration in wastewater treated by magnetite and zeolite could meet the integrated wastewater discharge standard（GB 8978—1996）（≤1.0 mg·L-1）. Adsorption of Pb2+ on zeolite, magnetic iron ore and gravel followed well the Langmuir equation , while the Freundlich equation is more suitable for descripting the Isothermal adsorption of magnetic iron ore. The adsorption capacity of zeolite to Pb2+ was higher than magnetic iron ore and gravel. On taking the adsorption effect and economic performance into consideration, gravel is the best wetlands substrates for the treatment of Pb2+ in wastewater, and the adsorption effect can be further improved by adding certain amount of zeolite. |
