Abstract:

Heavy metals, due to increased use in industries, lead to pollution in every part of the environment. The accumulation properties and their toxicity increase the importance of these pollutants and they are required to be treated. Adsorption, one of the treatment methods, is a cheap, easy to handle and effective alternative in heavy metal removal. A lot of adsorbents were used for this purpose that alginate is one of the examples. Alginate composed of mannuronic and guluronic acids is a biopolymer obtained from brown algae. Recently, the use of composite alginate beads made of some materials was increased. In this study, composite adsorbents with alginate and nano metal oxides were tested for heavy metal removal. Experiments were conducted at 100 mg/L of metal concentrations and varying pH (3 - 5.5) and adsorbent composition (Alginate/nano material ratio 1/2 - 2/1) by batch reactors. ZnO nano particles had the highest heavy metal removal efficiency among the selected nano metal oxides. When the effect of adsorbent composition was investigated, above 90% of Pb2+ and Cu2+ removal was achieved at alginate/nano ZnO of 2/1. pH 5.5 was determined as the optimal in the experiments performed by changing aqueous solution pH values in the range of 3 and 5.5. At this value, removal efficiencies were higher than 95% for Pb2+, Cu2+ and Cd2+. Therefore, composite alginate beads might be an alternative adsorbent for heavy metal removal.

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