Lead adsorption from aqueous solution using novel nanoparticles synthesized from waste aquatic weeds

Abstract

Pollution due to heavy metals has emerged to be an earth-shattering environmental concern over the past few decades. This has mainly been triggered by the rapid increasing industrial growth, possible toxic effects and high persistence in the environment. Aquatic macrophytes such as water hyacinth (WH) and duck weed (DW) were investigated for their ability as adsorbents for the removal of Pb(II) from aqueous solution. The synthesized nano-bio-adsorbents (WH and DW) were subjected to solgel process for the surface modification (M-WH and M-DW) and characterized using Brunauer, Emmett and Teller surface area analyzer, scanning electron microscopy, energy-dispersive X-ray and X-ray diffraction spectroscopy followed by thermogravimetry analysis. Dependence of adsorption on pH of solution, adsorbent dosage, metal ion concentration and contact time was studied to attain optimum condition. Adsorption isotherm was best suited with Langmuir, monolayer adsorption model with the maximum removal capacity of 111.11 mg/g (M-WH), 77 mg/g (M-DW) for Pb(II) ions, respectively. Adsorption kinetics fitted well with pseudo-second order shows good agreement between experimental and predicted results. Results of the present study reveal that surface-modified M-WH and M-DW aquatic weeds possess higher adsorption of Pb(II) ions from the waste streams.