Research Article
Yeh TY, Peng YP and Chen KF
Abstract
The biosorption mechanism of metal removal (copper, Cu and zinc, Zn) by four phytoremediation macrophytes biomasses including sunflower (Helianthus annuus), Chinese cabbage (Brassica campestris), cattail (Typha latifolia), and reed (Phragmites communis) was investigated in this study. The primary objectives were exploring the potential of reusing these bio-wastes after harvesting from phytoremediation operations. Based on the surface area, zeta potential, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) investigations, Chinese cabbage biomass presented the highest metal adsorption property while both cattail and reed revealed a lower adsorption capability for both metals tested. The equilibrium adsorption rate between biomass and metal occurred very fast during the first 10min. The metal adsorption data were fitted with the Langmuir and Freundlich isotherms and presented that the Langmuir isotherm was the best fitted model for all biomass tested. All tested biomasses are fast growing plants with fairly high biomass production that are able to accumulate metals. The Langmuir model was used to calculate maximum adsorption capacity and related adsorption parameters in this study. The results revealed that the maximum metal adsorption capacity Qmax was in the order of Chinese cabbage (Cu: 2000; Zn: 1111 mg/kg) > sunflower (Cu: 1482; Zn: 769 mg/kg) > reed (Cu: 238; Zn: 161 mg/kg) > cattail (Cu: 200; Zn: 133mg/kg). The harvested sunflower, Chinese cabbage, cattail, and reed biomass possess the potential to be employed as biosorbents to remove Cu and Zn from aqueous solutions. Adsorption isotherms derived in this study might be crucial information for practical design and operation of adsorption engineering processes and prediction of relation between reused macrophyte biosorbents and heavy metal adsorbates.