Synthesis and Characterization of Poly(pyrrole-1-carboxylic acid) for Preconcentration and Determination of Rare Earth Elements and Heavy Metals in Water Matrices

Abstract

Pyrrole was N-functionalized with solid carbon dioxide followed by chemical polymerization to create a new airstable, granular, and water-insoluble sorbent, poly(pyrrole-1carboxylic acid) (PPy-CO 2 ). PPy-CO 2 exhibited enhanced affinity for the sorption of metal ions compared to unfunctionalized PPy due to the incorporation of carboxylate functional groups directly onto the polymer backbone. As a freestanding sorbent material, immobilization to an additional solid support is not needed. Sorption, and therefore preconcentration, occurs simultaneously to achieve efficient removal and recovery of metal ions by a pHdependent sorption−desorption mechanism. PPy-CO 2 was evaluated on the analytical scale for the solid-phase extraction of a range of metal ions and found to efficiently preconcentrate rare earth elements (REEs), Th, and heavy metals (Cr, Fe, Cd, and Pb), which allowed quantitation by inductively coupled plasma mass spectrometry (ICP-MS). The impact of sorption parameters, such as solution pH, amount of sorbent, and sorption time, and the effect of desorption flow rate for recovery were investigated and optimized using ultrasound-assisted dispersive solid-phase extraction (UAD-SPE) with ICP-MS analysis. Maximum efficiency for sorption and recovery of most metal ions was achieved at a solution pH of 6.0, 10 mg of sorbent, a sorption time of 5 min, and desorption conditions of 1 mL of 2 M nitric acid applied at a flow rate of 0.25 mL min −1 . Detection limits for REEs and Th ranged from 0.2−3.4 ng L −1 for REEs and Th and 0.9−5.7 ng L −1 for heavy metals. Linear ranges from 0.1−1000 μg L −1 for REEs and 0.1− 500 μg L −1 for heavy metals and Th were also observed. PPy-CO 2 successfully preconcentrated and facilitated the determination of the targeted metal ions in water matrices of varying complexity, including tap water, well water, river water, and produced water samples. These results indicate the potential application of PPy-CO 2 for larger-scale recovery and removal of valuable or hazardous metal ions.

Unraveling the Complex Composition of Produced Water by Specialized Extraction Methodologies

“…For the analysis of inorganic elements, PPy-CO 2 was synthesized according to our previous report . pH measurements of PW were performed using a Basic pH Meter (Denver Instrument Company, Denver, CO).…”

“…A JEOL JSM-7500F scanning electron microscope (JEOL USA, Inc., Peabody, MA) equipped with a BRUKER XFlash 5010 series energy dispersive X-ray spectroscopy (EDS) detector (Billerica, MA) was used to obtain scanning electron microscopy (SEM) images and EDS spectra. The extraction protocol followed the procedure described by Rohanifar et al and used the optimized conditions for preconcentration and determination of rare-earth elements (REEs) with poly­(pyrrole-1-carboxylic acid (PPy-CO 2 ) …”

“…Therefore, to address these challenges, provide higher sensitivity, and remove potential interfering species, a tunable preconcentration step is often effective . Several studies have utilized solid-phase extraction (SPE) for preconcentration and recovery prior to trace level elemental analysis in complex samples. − Recently, our laboratory has developed a novel sorbent material (poly­(pyrrole-1-carboxylic acid); PPy-CO 2 ) for the preconcentration and determination of REEs, Th, and heavy metals (Cr, Fe, Cd, and Pb) using ultrasound assisted dispersive solid-phase extraction (D-SPE) followed by ICP-MS. , The selectivity of PPy-CO 2 for these elements is ideal for the extraction of trace level metals from complex matrices containing alkali and alkaline earths.…”

Tailoring Nanoadsorbent Surfaces: Separation of Rare Earths and Late Transition Metals in Recycling of Magnet Materials

“…As an alternative to the traditionally used methods, the application of solid-phase extraction (SPE) using nanosized functional adsorbents has been proven to be an effective and more environmentally friendly method for REE recovery [ 13 ]. Various types of nanosorbents have been synthesized for SPE recovery of REEs [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Several reviews have already been devoted to the discussion of the advantages and challenges in the application of functional solid adsorbents for REE separation [ 22 , 23 ].…”

Opportunities and limitations of membrane-based preconcentration for rapid and continuous diagnostic applications

“…Sample preconcentration has been pursued by many research groups, 13–26 but currently there is no universal method being used in the market without drawbacks in time consumption, cost, or the required use of bulky lab equipment. For example, a paper-based method has been demonstrated to preconcentrate influenza ribonucleic acid to increase the accuracy of Influenza A detection.…”