Determination Of Pb(II), Cu(II) And Ni(II) In Water By Direct Measurement Using Uv/Vis Spectrophotometer

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Date
2015-08
Authors
Tan, Chun Ho
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Heavy metal are metallic element with relatively high density and mostly toxic at low concentration. Heavy metal does not degrade and tends to bioaccumulate in organism over time. Current technique to determine heavy metals in water mostly via AAS, IC, ICP-AES, ICP-MS, XRF and electrochemical method,these techniques provide high precision in measurement but required high maintenance cost and complicated preparation. In this research, quantitative analysis of Pb2+, Cu2+ and Ni2+ ions in aqueous solution was carried out successfully using UV/VIS spectroscopy without additional chemical reagent. The research begins with identifying the effective absorption wavelength and was later verified using large amount of samples. From this research, the effective wavelength within UV range for Pb2+ and Cu2+ is roughly from 200 nm to 230 nm and both the Cu2+ and Ni2+ have absorbance from wavelength 600 nm to 800 nm. Also, the Ni2+ has high absorbance at wavelength 400 nm too. Furthermore, multicomponent analysis is used in order to calculate the concentration with overlapped spectra caused by mixture of Pb2+ and Cu2+ aqueous solution. There are total number of 50 extinction coefficient which correspond to 50 different wavelength from 201.20 nm to 223.39 nm are used to construct the multicomponent analysis equation. Finally, all regression model and multicomponent analysis equation obtained was compiled into a C# program which help to perform complex calculation. This program created for the removal of outliers, identification of ions, calculation of concentration, and root mean square error (RMSE) calculation. In this research, the accuracy of this detection method is0.178 mg/L, 0.243 mg/L, and 1.815 mg/L for Pb2+, Cu2+, and Ni2+ in aqueous solution with a detection limit of roughly 0.2 mg/L to 10 mg/L for Pb2+ and Cu2+ and 2 mg/L to 100 mg/L for Ni2+.
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Physics (General)
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