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Capability of chromophores-cellulose acetatechitosan membrane based colorimetric sensor for heavy metal detection

Capability of chromophores-cellulose acetatechitosan membrane based colorimetric sensor for heavy metal detection / Chan Zi Ying
Pengesanan logam berat di lokasi sumber air dengan cepat dan ringkas menggunakan kolorimetri sensor memainkan peranan yang penting dalam bidang industri, alam sekitar dan biologi sains. Namun, keupayaan kolorimetri sensor untuk menghasilkan pertukaran warna yang ketara amat bergandung kepada reagen optik seperti kromofor dan keadaan pengesanannya. Dalam pengajian ini, reagen optik seperti dithizone (DTZ), pyridylazo naphthol (PAN) and pyridylazo resorcinol (PAR) yang berfungsi untuk menghasilkan pertukaran warna telah digunakan untuk pengesahan Pb2+. Larutan DTZ pada pH4.11 didapati berupaya untuk menunjukkan transisi warna yang jelas dalam beberapa saat daripada hijau gelap kepada ungu semasa didedahkan kepada 0.25ppm Pb2+ (1ppm Pb(NO3)2) disebabkan pembentukan DTZ-Pb kompleks manakala pengesanan logam berat dengan menggunakan PAN dan PAR tidak dapat dikesan dengan mata kasar. Oleh itu, DTZ telah digunakan untuk mencipta sensor kolorimetri yang stabil dan canggih dengan memerangkap DTZ atas membran selulosa asetat/kitosan (CA/CS). Membran yang diterangkap dengan DTZ pada pH 4.11 menunjukkan respons yang paling bagus dalam keadaan pengesanan yang kering dan tanpa basuh dengan etanol semasa mengesan Pb2+. Selain itu, reaksi pembentukan DTZ-Pb kompleks juga telah diselidik dengan FTIR, SEM dan UV-vis spektroskopi. Keupayaan sensor kolorimetri yang berdasarkan kromofor-membran CA/CS untuk mengesan 0.25ppm Pb2+ (1ppm Pb(NO3)2) telah membuktikan aplikasinya dalam pengawasan pembuangan timah hitam menurut had yang ditetapkan dalam Environmental Quality (Sewage and Industrial Effluents) Regulations, 1979: Standard B (0.5ppm Pb). _______________________________________________________________________________________________________ Simple and fast on-site detection of heavy metals using colorimetric sensor plays an important role in various fields of industry, environment and biological sciences. However, the ability of a colorimetric sensor to induce a distinct color transition highly depends on the optical reagent, for example, type of the chromophore and its detecting conditions such as concentration and pH. In this study, optical reagents such as dithizone (DTZ), pyridylazo naphthol (PAN) and pyridylazo resorcinol (PAR) that responsible to induce color changes were used for Pb2+ detection. DTZ solution at pH4.11 was found to be capable of displaying distinct color transition from dark green to purplish within seconds upon exposed to 0.25ppm Pb2+ (1ppm Pb(NO3)2) due to formation of DTZ-Pb color complex whereas PAN and PAR didn’t provide naked eyes recognition of Pb2+ detection. Therefore, DTZ was used to further construct a stable and sophisticated colorimetric sensor by covalently immobilize DTZ on CA/CS membrane. DTZ at pH 4.11 immobilized on membrane strip had showed the most attracting result in response to Pb2+ in dry sensing condition and without ethanol washing. Besides, the complexation reaction of lead with DTZ has also been explored by FTIR, SEM and UV-vis spectroscopy. Capability of DTZ-CA/CS membrane based colorimetric sensor to detect 0.25ppm Pb2+ (1ppm Pb(NO3)2) had proved its practical application in lead emission monitoring comply with the limit of Environmental Quality (Sewage and Industrial Effluents) Regulations, 1979: Standard B (0.5ppm Pb).
Contributor(s):
Chan Zi Ying - Author
Primary Item Type:
Final Year Project
Identifiers:
Accession Number : 875007513
Language:
English
Subject Keywords:
detection; heavy metals; colorimetric sensor
First presented to the public:
6/1/2018
Original Publication Date:
7/18/2018
Previously Published By:
Universiti Sains Malaysia
Place Of Publication:
School of Chemical Engineering
Citation:
Extents:
Number of Pages - 86
License Grantor / Date Granted:
  / ( View License )
Date Deposited
2018-07-18 11:50:44.418
Date Last Updated
2019-01-07 11:24:32.9118
Submitter:
Mohd Jasnizam Mohd Salleh

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Capability of chromophores-cellulose acetatechitosan membrane based colorimetric sensor for heavy metal detection1 2018-07-18 11:50:44.418