Nickel adsorption by lignin from contaminated water
Shornikov, Evgenii (2023)
2023
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2023060923312
https://urn.fi/URN:NBN:fi:amk-2023060923312
Tiivistelmä
The aim of this thesis was to compare the adsorption properties of hydrogen peroxide modified ionic liquid lignin with those of its unmodified version.
The study was conducted as a continuation of lignin research, and the results of previous studies were used in the process development. Modification of lignin with hydrogen peroxide was chosen because of the relative simplicity of the process and the assumed efficiency. Evaluation methods included Fourier trans-form infrared spectroscopy and flame atomic adsorption spectroscopy. FT-IR was used to determine the bond structure of lignin. FAAS was used to study the adsorption properties of modified lignin compared to unmodified lignin.
The results of the study showed that hydrogen peroxide modification was successful in oxidizing the lignin structure and introducing additional carboxylate group bonds, which increased the metal adsorption of the modified lignin structure. The FAAS results showed an initial nine-fold increase in absorption capacity after modification. However, nickel ions were released back into solution after the initial absorption, and the final measurement showed a moderate four-fold difference between the results for modified and unmodified lignin.
Further studies are needed on the adsorption mechanisms and to explain the behaviour of metal ions released from the modified lignin structure.
The study was conducted as a continuation of lignin research, and the results of previous studies were used in the process development. Modification of lignin with hydrogen peroxide was chosen because of the relative simplicity of the process and the assumed efficiency. Evaluation methods included Fourier trans-form infrared spectroscopy and flame atomic adsorption spectroscopy. FT-IR was used to determine the bond structure of lignin. FAAS was used to study the adsorption properties of modified lignin compared to unmodified lignin.
The results of the study showed that hydrogen peroxide modification was successful in oxidizing the lignin structure and introducing additional carboxylate group bonds, which increased the metal adsorption of the modified lignin structure. The FAAS results showed an initial nine-fold increase in absorption capacity after modification. However, nickel ions were released back into solution after the initial absorption, and the final measurement showed a moderate four-fold difference between the results for modified and unmodified lignin.
Further studies are needed on the adsorption mechanisms and to explain the behaviour of metal ions released from the modified lignin structure.