Evaluation pf razor clam (Ensis directus) shell as an adsorbent for removal of heavy metals and dyes from aqueous solution
This research aimed to evaluate the potential of razor clam (Ensis directus) shell, afishery waste material, as an adsorbent for the removal of heavy metals and dyes from aqueoussolution. This research is divided into three parts, namely characterisation studies, adsorptionstudies and desorption stu...
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| Format: | thesis |
| Language: | zsm |
| Published: |
2018
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| Subjects: | |
| Online Access: | https://ir.upsi.edu.my/detailsg.php?det=21 |
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| Summary: | This research aimed to evaluate the potential of razor clam (Ensis directus) shell, afishery waste material, as an adsorbent for the removal of heavy metals and dyes from aqueoussolution. This research is divided into three parts, namely characterisation studies, adsorptionstudies and desorption studies. Several analytical instruments such as scanning electron microscope(SEM), energy dispersive x-ray (EDX) spectrometer and Fourier transform infrared (FTIR)spectrometer were used to characterise the adsorbent. In this study, three metal ions (Cd(II),Cu(II) and Pb(II)) and four dyes (Congo red (CR), methylene blue (MB), Rhodamine B (RB) and methylorange (MO)) were used as contaminants. A series of adsorption tests were carried out as a functionof solution pH, adsorbent dosage and initial adsorbate concentration. The adsorption capacity ofrazor clam shell for metal ions and dyes from aqueous solutions was evaluated in both single andmix systems. The desorption study was performed using hydrochloric acid, acetic acid and sodiumhydroxide as desorption agents. The adsorption efficiency of the proposed adsorbent was comparedwith olive tree derived activated carbon, a commercial adsorbent for water treatment in Libya.Research findings showed that the surface morphology of razor clam shell changed after metal ionsand dyes uptake, indicate a relevant adsorbate-adsorbent interaction. With an exception of MB, theadsorption of contaminants studied was more favourable at acidic pH media. The Freundlich andLangmuir isotherm models were employed to correlate the adsorption equilibrium data. Based onLangmuir isotherm model, the maximum adsorption capacities of razor clam shell were calculated as103 mg/g, 98 mg/g and 357 mg/g for Cd(II), Cu(II) and Pb(II) ions, respectively. Meanwhile, themaximum adsorption capacities for CR, MB, MO and RB were determined as 115 mg/g, 24 mg/g, 9 mg/gand 1.16 mg/g, respectively. In conclusion, the presence of carbonate functional group on thesurface of razor clam shell was beneficial for adsorption mechanism. In implication, theapplication of razor clam shell as a low-cost adsorbent could reducethe operational cost for water treatment in developing countries. |
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