Quantitative Analysis of Polymetallic Ions in Industrial Wastewater Based on Ultraviolet-Visible Spectroscopy

Abstract

In order to detect and control the concentration of polymetallic ions in industrial wastewater in real time, a spectrophotometric method combining wavelet transform (WT) and partial least squares regression (PLSR) is proposed for the simultaneous determination of zinc, cobalt and nickel in industrial wastewater by ultraviolet-visible spectrometry, without a separation step. WT was found to be suitable for spectral preprocessing, which effectively eliminated the noise, enhanced spectral feature information, improved the linearity of the detected ions and increased the number of selectable modeling wavelengths. PLSR was used to study the simultaneous detection of zinc, cobalt and nickel. The linear detection ranges were 10–100 mg/L for zinc, 0.6–6.0 mg/L for nickel and 0.3–3.0 mg/L for cobalt. The average relative deviation for zinc, nickel and cobalt was 2.85%, 3.05% and 2.24%, respectively. The results indicated that the WT–PLSR method is suitable for the online detection of polymetallic ions by ultraviolet-visible spectroscopy in zinc industrial wastewater.

Determination of copper(ii) and lead(ii) ions in dairy products by an efficient and green method of heat-induced homogeneous liquid–liquid microextraction based on a deep eutectic solvent

“…Of course, due to the scientic progress achieved in the eld of detection and determination of heavy metals, various analytical methods are used, and obtaining a solution is somewhat facilitated. Among these methods, the following can be mentioned: ame atomic absorption spectrometry (FAAS), 8,9 voltammetry, 10,11 electrothermal atomic absorption spectrometry (ETAAS), 12,13 inductively coupled plasma-mass spectrometry (ICP-MS), 14,15 ultraviolet-visible spectrophotometry, 16 and ICP-optical emission spectrometry (OES). 17,18 Although some of the mentioned techniques such as ETAAS, ICP-MS, and ICP-OES are sensitive, problems such as high cost and requiring an expert user limit their usage especially in small laboratories.…”