Preconcentration and Determination of Trace Hg(II) Using a Cellulose Nanofiber Mat Functionalized with MoS₂ Nanosheets

Abstract

Molybdenum disulfide (MoS 2 ) nanoparticles were hydrothermally synthesized onto the surface of a cellulose nanofiber mat and demonstrated for the selective extraction and preconcentration of trace Hg(II) from aqueous media. Immobilization of MoS 2 onto solid support restricts sorbent loss during a column operation. The surface morphology and chemical bonding of the prepared material were characterized by scanning electron microscopy, tunneling electron microscopy, and X-ray photoelectron microscopy. The selective sorption of Hg(II) is mainly attributed to the soft−soft interaction of Hg(II) with the S atoms of the MoS 2 . The experimental data shows good Hg(II) sorption capacity and was found to be 160.4 mg g −1 . The limit of detection and limit of quantification of the proposed method were found to be 0.09 and 0.30 μg L −1 , respectively. The accuracy of the method against the systematic and constant errors was confirmed by the analysis of the Standard Reference Material (>95% recovery with <5% RSD). Student's t-test values were found to be less than the critical Student's t value at a 95% confidence level. The developed method was successfully employed for the preconcentration and determination of Hg(II) in water samples.

Recent Advances in Two-Dimensional MoS2 Nanosheets for Environmental Application

“…The removal, separation, and detection of Hg(II) from aqueous solutions using MoS 2based composites were reviewed herein. 9,205,206,224,225,230,231 Ai et al first used MoS 2 as the adsorbent to remove Hg(II) in 2016. 224 The excellent mercury uptake capacity (2506 mg/ g) and large distribution coefficient (2.53 × 10 8 mL/g) was due to the wider interlayer spacing (Figure 7A).…”

“…206 Hassen et al found the low limit of detection MoS 2 for Hg(II) (0.09 μg/L). 225 Fausey et al demonstrated that MoS 2 -based fibers via bottom-up methods showed fast removal equilibrium (0.436 min −1 mg −1 ) and high Hg 0 removal capacity (6258.7 mg/g). 231 The removal mechanism between 2D MoS 2 -based and Hg(II) has been investigated by many researchers.…”

“…The heavy-metal ions are too large to enter the interior sulfur surface of bulk MoS 2 , because of the tiny free spacing (0.3 nm) of two neighboring layers . Thus, various MoS 2 -based composites have been fabricated to enhance the exposure of heavy metals with sulfur sites and increase removal performance. ,, For instance, Wang et al fabricated a quasi-single-layer MoS 2 /TiO 2 nanocatalyst using ammonium tetrathiomolybdate as a Mo precursor, which enhanced the exposure of active sites and avoided the self-aggregation of MoS 2 nanosheets . It is reported that the adsorption capacities of MoS 2 -based composites (e.g., C@MoS 2 /montmorillonite (187.0 mg/g at 298 K), MoS 2 /reduced graphene oxide composites (384.16 mg/g, Figure B) CoFe 2 O 4 –MoS 2 –chitosan (660.67 mg/g)) were significantly higher than the other MoS 2 -based composites, such as MoS 2 /graphene (322 mg/g) and MoS 2 /CeO 2 nanohybrids (333 mg/g at pH 2.0) .…”

Graphene oxide lamellar membrane with enlarged inter-layer spacing for fast preconcentration and determination of trace metal ions

“…Although all these techniques have several advantages such as, low detection limit, multi-elemental analysis, large dynamic linear range, high sample throughput, however, direct determination of trace heavy metal ions with complex sample matrices, such as environmental water samples is still challenging due to matrix interferences. [11][12][13] Therefore, a sample extraction and preconcentration techniques are the prerequisite step to eliminate any matrix components and consequently improving the detection limit are of signicant importance.…”

3D Nanoarchitecture of Polyaniline-MoS2 Hybrid Material for Hg(II) Adsorption Properties

“…Modern analytical techniques such as X-ray fluorescence, atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, and inductively coupled plasma mass spectrometry have been widely used for the analysis of Hg(II) [ 9 , 10 , 11 ]; however, direct determination of Hg(II) in real aqueous samples is challenging due to their low concentrations and complexity of sample matrices [ 12 ]. Therefore, preliminary extraction and preconcentration steps are often necessary before instrumental determination.…”