Use of Gold Nanoparticles as Substrate for Diffusive Monitoring of Gaseous Mercury

Abstract

In the present work, the study and the performances of an adsorbent material for gaseous mercury employed in different diffusive bodies geometries is presented. The material is based on gold nanoparticles (AuNPs) deposited on quartz fibres filters, suitable for bonding the gaseous mercury through an amalgamation process. Following thermal desorption and analysis, the behavior of different diffusive samplers prototypes was compared. Both indoor and outdoor exposures were carried out in order to evaluate the advantages and shortcomings of the geometries in study at different sites. From the outdoor long-term exposures, a constant uptake rate (Ur), with a low influence coming from the environmental conditions, was observed for the axial geometry, reporting a high coefficient of determination (R2 0.97). Indoor exposures showed a higher reproducibility, along with a higher coefficient of determination (R2 0.99). The presented results allowed us to observe different behaviors coming from two kinds of diffusive samplers designs, showing different adsorption rates and data dispersion. This allowed us to focalize our attention on the most suitable design from these two tested prototypes, for this kind of adsorbent material.

Characteristics and Performances of a Nanostructured Material for Passive Samplers of Gaseous Hg

“…Such a decreasing trend of SR was also observed by Papa et al (2018) in axially diffusive PASs based on gold NPs deposited onto quartz fibers and differently arranged on the surface. The SR value was confirmed to be higher the first day of exposure, then decreasing gradually during the first week until stabilizing during the following days [ 36 ]. In the present study, too, after the first week of exposure, SR remained constant (about 1.398 × 10 −2 ± 0.051 × 10 −2 m 3 /day) for both PAS-0.4mg and PAS-4mg until ≈30 d. In PAS4mg, SR remained apparently almost stable even for a longer period, with a maximum decrease of about 3% (1.356 × 10 −2 ± 0.061 × 10 −2 m 3 /day) after 198 days ( Figure 6 ).…”

“…The ability of gold to desorb mercury at ≈500 °C could allow, in principle, the reusing of the adsorbing material for more measurements. Although this capacity is well known in the literature, the PAS-based resampling was conducted in only a few studies [ 35 , 36 , 37 , 38 , 43 ].…”

“…However, since the analytical method to measure the adsorbed mercury is digestion, these adsorbing materials are disposable. Samplers based on gold materials in thin films [ 12 , 31 , 32 ] or nanoparticles (NPs) [ 33 , 34 , 35 , 36 , 37 ] have been developed and used in both active [ 12 , 38 ] and passive mercury samplers [ 31 , 33 , 35 , 36 , 37 ] for TGM monitoring. The high affinity between mercury and gold enables the uptake of little concentrations of mercury species upon amalgam formation.…”

Chitosan-Based Polymer Nanocomposites for Environmental Remediation of Mercury Pollution

“…Samplers based on chitosan nanomaterial thin films or nanoparticles (NPs) [ 191 , 192 ] have been developed because of the strong electrostatic attraction mechanism. They are based on the second most abundant biopolymer and are inexpensive, re-usable and biodegradable; hence, they are used in passive mercury samplers for mercury uptake [ 61 ].…”