A rapid extraction of toxic styrene from water and wastewater samples based on hydroxyethyl methylimidazolium tetrafluoroborate immobilized on MWCNTs by ultra-assisted dispersive cyclic conjugation-micro-solid phase extraction

Abstract

The styrene affected on human health and caused cancer and dysfunction in the central nervous system (CNS) and liver. So, sensitive techniques for the separation and determination of styrene in water and wastewater samples are necessary. In this study, a novel task-specific ionic liquid (TSIL) immobilized on multi-walled carbon nanotubes (MWCNTs@[Hemim][BF4]) was synthesized with a new approach for extraction of styrene from water samples by ultra-assisted dispersive cyclic conjugation-micro-solid phase extraction procedure (USA-DCC-µ-SPE). Due to procedure, 30 mg of MWCNTs@[Hemim][BF4] was mixed with 20 mL of water or standard styrene solution (0.001–6.5 mg L−1) in the centrifuge Pyrex tube (CPT, 20 mL) by stirring for 12 min (25 °C). After extraction of styrene based on the cation/anion π–π interactions and imidazolium ring of TSIL with π system/vinyl group of styrene, the MWCNTs@[Hemim][BF4] adsorbents were collected at the bottom of the conical tube. The upper liquid phase set aside by the auto-sampler and 0.2 mL of ethyl benzene added to the remained solid phase at 70 °C. After back extraction of styrene in ethyl benzene, the styrene values were measured with a gas chromatography-flame ionization detector (GC-FID). All effective parameters such as the sample volume, the amount of sorbent, temperature, and the sonification time were studied. The linear range (LR), the detection limit (LOD) and re-usage of adsorbent were obtained 0.001–6.5 mg L−1, 0.26 μg L−1 and 18 times, respectively (r = 0.9997, RSD%=1.45). Due to TGA curve, the weight loss (7 wt%) for MWCNTs@[Hemim][BF4] was occurred at more than 350 °C. The absorption capacities of MWCNTs@[Hemim][BF4] and MWCNTs for 100–200 mg L−1 of standard styrene solution were obtained 183.2 mg g−1 and 24.8 mg g−1, respectively. The procedure was validated by GC–MS and spiking samples.