Optical Detection and Efficient Removal of Transition Metal Ions from Water using Poly(hydroxamic acid) Ligand
A copolymer, cellulose-graft-poly(methyl acrylate), was synthesized by a free-radical initiating process, and the ester functional groups converted into the hydroxamic acid ligand. The pH of the solution acts as a key factor in achieving optical color signals of metal-complexation. The reflectance s...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier Ltd
2017
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| Subjects: | |
| Online Access: | http://umpir.ump.edu.my/id/eprint/16398/ http://umpir.ump.edu.my/id/eprint/16398/ http://umpir.ump.edu.my/id/eprint/16398/ http://umpir.ump.edu.my/id/eprint/16398/1/Optical%20detection%20and%20efficient%20removal%20of%20transition%20metal%20ions.pdf |
| Summary: | A copolymer, cellulose-graft-poly(methyl acrylate), was synthesized by a free-radical initiating process, and the ester functional groups converted into the hydroxamic acid ligand. The pH of the solution acts as a key factor in achieving optical color signals of metal-complexation. The reflectance spectra of the [M-ligand]n+ complex was found to be at the highest absorbance, ranging from 92 to 99% at pH 6, with absorbance noted to increase as metal ion concentrations were increased. A broad peak at 673 nm for Cu2+ was observed, indicating the presence of the charge transfer (π–π transition) complex. The developed ligand demonstrated superior adsorption capacity for copper (305.3 mg g−1), as well as strong adsorption capacity for other metals; the adsorption capacities for Fe3+, Mn2+, Co2+, Cr3+, Ni2+, and Zn2+ were 275.6, 258.5, 256.6, 254.3, 198.5, and 190.1 mg g−1, respectively. The experimental data of the adsorption kinetics of the metal ions fitted well with a pseudo-second-order rate equation. The obtained data demonstrated that the observed metal ion sorption was well fitted with the Langmuir isotherm model (R2 > 0.99), suggesting that the surface of the adsorbent is homogenous and monolayer. The reusability of the ligand was verified using the sorption/desorption process, demonstrating that the developed adsorbent can be reused for 12 cycles without significant loss of its original sensing and removal performance. |
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