e-Polymers (Aug 2013)
Tuning of heavy metal removal efficiency from water via micro algae/hydrogel composites
Abstract
A series of micro algea-based hydrogel composites were prepared from polyacrylamide and Spirulina (PAAm-sp). Free radical polymerization of acrylamide (AAm) in the presence of N,N-methylene bis-acrylamide (BAAm), as a crosslinker, and Spirulina microalgae in different loadings was conducted. Chromium metal adsorption capacity was determined with UV-VIS spectroscopy whereas mechanical performance of the resultant hydrogel composites was followed with uniaxial compression experiments. It has been found that efficiency can be tuned by Spiriluna composition in hydrogel. PAAm hydrogel composite having 0.5 % Spirulina had the maximum compression strength, good swelling in water as well as improved thermal stability due to the special and beneficial ‘fishnet morphology” observed via scanning electron microscopy (SEM). The observed high performance of this composition is proved to be due to this morphology where all potential binding sites are under receptive position for metal adsorption. Spirulina by itself in water can remove only about 2 % of its weight of Cr+3 ion, however in the hydrogel structure this removal increases up to 200 % which makes this biotechnological approach superior in the metal removal from the water.