Preparation and Characterization of Silica-Carrageenan Adsorbent for Pb2+ and Cd2+as Interfering Ion

Abstract

Pb2+ and Cd2+ are poisonous heavy metal ions produced by industrial waste. Waste processing is always required before such material is released into the environment. A safe biomaterial such as silica-carrageenan was designed for the heavy metal adsorbent. The objectives of this research were to prepare and characterize silica-carrageenan adsorbent as well as testing them in some applications, by thin layer chromatography as well as in batch methods. Adsorption profiles of the two heavy metal ions were expected. The result showed that this material contained 1.10 g/cm3 density, 2.10% moisture level, 81.70% ash level, and iodine adsorption value of 21.80%. SEM pictures showed the homogeneous structures with globular particle shape below 100 nm dimension. FT-IR spectra showed the presence of the siloxane groups (≡Si-O≡), silanols (≡Si-OH-), and-OH groups from carrageenan. Both ions could not be eluted by all of the organic eluents on TLC plates of the material, but less than 50% of Pb(II) can be separated. This adsorption value decreased in the presence of Cd(II) in the silica-carrageenan system in batch method.