Enhancement of activated carbon using nickel and carbon nanofibers (CNFs) for heavy metal removal /
In the recent years, a great attention has been given on the application of nano materials as adsorbents to remove toxic and harmful substances from water and wastewater. In this study, the removal of lead ions (Pb2+) from aqueous solution by using carbon nanofibers (CNFs) as adsorbent was investiga...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur:
Kulliyyah of Engineering, International Islamic University Malaysia,
2012
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| Subjects: | |
| Online Access: | http://studentrepo.iium.edu.my/handle/123456789/4758 |
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| Summary: | In the recent years, a great attention has been given on the application of nano materials as adsorbents to remove toxic and harmful substances from water and wastewater. In this study, the removal of lead ions (Pb2+) from aqueous solution by using carbon nanofibers (CNFs) as adsorbent was investigated. CNFs were produced from nickel impregnated powdered activated carbon (PAC) by Chemical Vapor Deposition (CVD) of acetylene in the presence of hydrogen. Various weight percentages (1, 3, 5, and 7%, respectively) of the catalyst salt (Ni2+) were used for the impregnation of Ni2+ into PAC. Design Expert software was used to design the experimental plan and to determine the optimization parameters for the growth of CNFs, considering sorption capacity of Pb2+ by the CNFs as a response. Based on the screening test, the solution with the highest sorption capacity was chosen for detailed study. Field Emission Scanning Electron Microscope (FESEM), Transmission Electron Microscope (TEM), Fourier Transform Spectroscopy FTIR, Energy Dispersive X-Ray Analyzer (EDX), Thermal Gravimetric Analysis (TGA), zeta potential and Brunauer, Emmett and Teller (BET) were used for the characterization of the selected sample. FESEM and TEM showed the graphitic structure of the CNFs. The PAC surface area was noticed to be increased after the growth of CNFs (from 101 m2/g to 837 m2/g). TGA combustion temperature range was within 400 °C and 570 °C. Zeta potential was – 24.9 mV. A comparison between the commercial PAC and the PAC-CNFs was done for the removal of Pb2+ from synthetic wastewaters. It was observed found that the removal of Pb2+ was about 91% for the PAC-CNFs and PAC, respectively. Statistical design was also used to optimize the removal of heavy metals from water with CNFs dose, pH, contact time and agitation speed as controlling parameters. The optimum conditions were CNFs dose of 0.25 g/L, pH 5.5, contact time 60 min and agitation speed of 200 rpm. Langmuir and Freundlich adsorption isotherms were studied for the novel adsorbent. The system was found better following Langmuir model rather than Freundlich. Langmuir maximum sorption capacity (qm) was 166.66 mg/g, Langmuir constant Kl was 0.17 and correlation coefficient (R2) 0.965. Freundlich model constants were Kf 28.97 n 2.2 and R2 0.903. Three adsorption kinetic models were studied, zero-order model with correlation coefficient (R20.234 and K 0.032 (mg/min.L), pseudo-first-order model with R2 equals 0.941, adsorption capacity at equilibrium (qe) 29 (mg/g) and rate constant of the first order (K1) 0.033 (min-1) and pseudo-second-order model with R2 0.999, adsorption capacity at equilibrium (qe) 74.79 (mg/g) and sorption rate constant (K2) 0.029 (min. g/mg). The product was also used for the removal of lead from industrial wastewater and it was successful for the removal of 67 % of lead ions from semiconductor wastewater sample which contained boron and cyanide as well. |
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| Item Description: | Abstract in English and Arabic. "A thesis submitted in fulfillment of the requirement for the degree of Doctor of Philosophy in Engineering."--On t.p. |
| Physical Description: | xix, 160 leaves : ill. ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 124-146). |