Selective adsorption of Pb(II) from aqueous solution using porous biosilica extracted from marine diatom biomass: Properties and mechanism

• Published in: Applied surface science Vol. 396; pp. 965 - 977
• Main Authors: Qi, Yarong, Wang, Jingfeng, Wang, Xin, Cheng, Jay Jiayang, Wen, Zhiyou
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 28.02.2017
• Subjects: Biosilica; Heavy metal removal; Marine diatom; Pb(II) adsorption; Selective separation; Selective separation; Biosilica; Pb(II) adsorption; Marine diatom; Heavy metal removal
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.11.069

[Display omitted] •Highly pure biosillica with abundant pores was prepared from marine diatom biomass.•The biosilica possessed higher adsorption capacity of Pb(II) than most of inorganic adsorbents.•The biosilica can selectively adsorb Pb(II) from a solution containing Cu, Cd, Ni and Ag ions.•Porous structure and impurities of the biosilica were two main contributors to Pb(II) adsorption. Biosilica with a surface area of 143m2g−1 derived from marine diatoms was prepared using an easy two-step method involving washing with dilute acid and baking. The extracted biosilica was used to remove divalent lead ions, i.e., Pb(II), from aqueous solution. The effects on Pb(II) adsorption of initial pH, shaking speed, and adsorbent loading were investigated. The adsorption of Pb(II) in the presence of other ions was also investigated. The biosilica showed a high adsorption capacity with high selectivity for Pb(II). The experimental maximum adsorption capacity was 108.2–120.4mgg−1 at an adsorbent loading of 1gL−1. The adsorption process was best described by the Langmuir model. The adsorbent selectively adsorbed Pb(II) from binary ion systems in the presence of Cu(II), Cd(II), Ni(II), and Ag(I). The results of this study show that biosilica extracted from fresh marine diatoms is a more efficient and selective adsorbent for Pb(II) than other inorganic adsorbents.