Silver biosorption study by using seaweed-based sorbents

Abstract

Biosorption is a green and effective alternative for metal recovery. Few researches on silver biosorption has been conducted by using seaweed species. This thesis conducted investigations into silver biosorption behavior of algae-based biosorbents. Laminaria Japonica and two Fucus species (Fucus spiralis and Fucus vesiculosus) was selected to experience some pretreatments. DOE (design of experiment) was employed to plan and analyze the tests for maximal silver capacity and selectivity between with copper ions. Seaweed species and pretreatments were verified to be the most significant factors in the biosorbent preparation. The silver biosorption on Fucus species was a rapid reaction, time-efficient for industrial application, which kinetic experiment data can be well described by Pseudo-second order equation. The mathematical maximal silver uptake by pretreated Fucus spiralis with acetone is around 78 mg/g at pH of 4.8 and is 120 mg/g at pH of 6.3, based on fitted Langmuir isotherm model. Characterization study of X-ray diffraction confirm the state of silver on the solid sorbent after tests, and Raman spectra and FTIR provided binding information between silver ions and functional groups on the targeted biosorbents. Compared with other reported biosorbent on silver recovery, this study demonstrates the utility of Fucus species as a promising potential candidate for silver biosorption in a competing environment.