THESIS
2012
xii, 126 p. : ill. (some col.) ; 30 cm
Abstract
Heavy Metal contamination in water bodies has devastating effect on the environment and human health and therefore needs to be prevented. Those removed heavy metals can be also be recovered and reused, saving raw materials and cost. However, the wastewater sometimes contains a mixture of different metal species which proves to be challenging in recovering individual metals. There is also more interest in heavy metal recovery from solid waste, especially electronic waste, which is one of the fastest growing waste in the world today and a high portion of it is made of metal. Acid leaching or bioleaching can solubilize metals, however this process often releases a mixture of metals into the solution, therefore selective adsorption could play an important role in the development of downstre...[
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Heavy Metal contamination in water bodies has devastating effect on the environment and human health and therefore needs to be prevented. Those removed heavy metals can be also be recovered and reused, saving raw materials and cost. However, the wastewater sometimes contains a mixture of different metal species which proves to be challenging in recovering individual metals. There is also more interest in heavy metal recovery from solid waste, especially electronic waste, which is one of the fastest growing waste in the world today and a high portion of it is made of metal. Acid leaching or bioleaching can solubilize metals, however this process often releases a mixture of metals into the solution, therefore selective adsorption could play an important role in the development of downstream process in metal recovery. Chelating resin-Suqing, Chitosan and NH
2MCM41 have been selected to study their selectivity in metal adsorption, each representing a different category of adsorbents. copper sulfate, nickel sulfate and zinc sulfate were selected as the metal species to relate this study of recovering metals from bioleaching solution of Printed Circuit Boards using Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans, furthermore sulfuric acid is a well-known industrial leaching agent so it is worth investigating the metal sulfate adsorption system. Binary component adsorption system of different metal combinations was tested. It was found that copper was the most preferred metal to be adsorbed in all 3 adsorbents. NH
2MCM41 is able to separate all 3 metals completely whereas Suqing and Chitosan adsorbed Ni and Zn at 1:1 ratio. Suqing has selectivity in the order of Cu>Ni>Zn but in the case of NH
2MCM41 and Chitosan, it is Cu>Zn>Ni. Binary adsorption system of cadmium and copper formate as well as cadmium and copper acetate are also investigated for NH
2MCM41 to study the effect of anion type on selectivity, it was found that the presence of organic anion does not have an effect on the selectivity of NH
2MCM41 towards Cu.
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