Adsorption of heavy metal ions by the biomass of solanum elaeagnifolium (silverleaf night-shade)

摘要

A creening proeviously performed for metal concentration in desert plants indicated that Solanum elaeagnifolium (silverleaf nightshade) and the potential to be used as a biomaterial for heavy metal removal from contaminated solis and waters. The Pb(II), Cu(II), Ni(II), Cd(II), Zn(II), Cr(III), and Cr(VI) binding properties of native and NaOH)modified biomass of Solanum elaeagnifolium were studied. Batch experiments were conducted with oven-dried and ground leaves of Solanum elaeagnifolium to characterize the metal-binding properties. These experiments in cluded pH profiles, time dependencies, and metal-binding capacities of the biomass. Results rom this work have indicated that optimal metal binding occurred at pH 5.0 for Pb(II), Cu(II), Ni(II), Cd(II), Zn(II), and Cr(III) whin a 10-15 minute time period. However, optimal Cr(VI) binding occurred at pH 2.0. Capacity experiments showed that native Slanum elaeagnifolium was able to bind the following amounts of metals in mg metal/g biomass: 20.6 mg Pb(II)/g, 13.1 mg Cu(II)/g, 6.5 mg Ni(II)/g, 18.9 mg Cd(II)/g, 7.0 mg Zn(II)/g, 2.8 mg Cr(III)/g, and 2.2 mg Cr(VI)/g. However, the NaOH-modified biomass of Solanum elaeagnifolium showed an increase in metal binding for most of the metal ions studied. By treatment with HCI, the bound-metal ions were recovered. These results indicate that the biomass of SOlanum elaeagnifolium can be chemically modified with NaOH and can be used to remove several metal ions from aqueous solution. In addition, silica-immobilizied Solanum elaeagnifolium was used in columns for flow studies which show that silverleaf nightshade could be used to remediate heavy metal-contaminated waters in a cost-efficient manner.