ICP-OES Determination of Titanium (IV) in Marine and Wastewater Samples after Preconcentration onto Unloaded and Reagent Immobilized Polyurethane Foams Packed Columns

El-Shahawi Ms Bashammakh As

doi:10.4172/2157-7064.1000247

Abstract

A novel method that utilizes untreated and polyurethane foam (PUF) physically immobilized with the reagent 4-(2-pyridylazo) resorcinol (PAR) or 2, 3, 5-triphenyl-2H-tetrazolium chloride (TZ+Cl-) as solid phase extractor packed column has been developed for preconcentration and subsequent determination of titanium(IV) ions in marine and wastewater samples. The method is based on retention of the titanium(IV) traces present in aqueous media at pH 3-4 onto the reagent treated PUF packed column, followed by recovery with HNO3 (2.0 mol dm-3) and subsequent ICP-OES determination. The uptake of titanium species onto the unloaded- and reagent impregnated PUF was fast and followed a first-order rate equation. Titanium sorption onto PUF followed Langmuir, Freundlich and Dubinin- Radushkevich (D-R) type isotherm models. Thus, a dual-mode sorption mechanism involving absorption related to “weak-base anion exchange” and an added component for “surface adsorption” seems a more likely retention model. PAR-immobilized PUF packed column has been applied successfully for complete collection of titanium(IV) species in fresh and wastewater samples at low level of titanium (<0.5 ng Ti mL-1) at pH 3-4. The retained titanium species were then recovered (97-101%) from the packed column with HNO3 and determined by ICP-OES. The proposed PUF packed column method was further applied for analysis of picomolar concentrations of dissolved Ti species in marine water.

Highlights

Titanium is well known for its excellent corrosion resistance, having ability to withstand attack by dilute H2SO4 and HCl or even moist chlorine
The concentrations of heavy metals in natural water and wastewater samples are frequently lower than their limit of detection (LOD)
The observed behavior of titanium(IV) species sorption onto the unloaded and TZ+Cl- loaded polyurethane foam (PUF) at pH 3.1-4.0 is most likely attributed to the formation of binary and ternary complex ion associates of titanium (IV) with PUFs via protonated ether (-CH2-O+H-CH2-) oxygen linkage of the PUF and TZ+Cl- loaded PUF, respectively

Summary

Introduction

Titanium is well known for its excellent corrosion resistance, having ability to withstand attack by dilute H2SO4 and HCl or even moist chlorine. Separation and determination of titanium (IV) at trace levels in different matrices including industrial wastewater have been reported employing solid phase extraction (SPE) [6,7,8,9,10,11]. Developing a convenient and low cost extraction procedure for separation and subsequent ICP-OES determination of titanium (IV) species in water samples employing PAR immobilized PUF in packed column and iii. A Perkin Elmer Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES, Optima 4100 DC Shelton, CT, USA) was operated at the optimum instrumental parameters for titanium determination before and after extraction with the reagent treated PUFs under the optimum operational parameters (Table 1). Self-made columns (16, 10 and 2 cm h and 10 mm id) were used in flow experiments

Recommended procedures

Results and Discussion

Conclusion