A diffusive gradients in thin-films technique for the assessment of bisphenols desorption from soils

Abstract

Desorption/adsorption of bisphenols (BPs) in soils affects their mobility and availability. However, the kinetics of these processes have not been well studied, due to the lack of appropriate means of measurement. Diffusive gradients in thin-films (DGT) technique can assess kinetic processes in soils and have recently been developed for measuring three BPs (BPA, BPB and BPF). DGT was deployed for 2.5h to 20 d in five soils with different soil properties. Non-linear increase in mass accumulation by DGT with time indicated poor resupply of BPs from soil solid to solution phase. By fitting the data with DIFS (DGT-induced fluxes in soils) model, values for the labile partition coefficient (K), response time (t) and rates of exchange (k and k) of BPs between soil solid and solution phases were obtained. The derived values of K showed that most of the BPs in the soil could participate in labile exchange. Average response times of 1-2h implied that the supply of BPs to DGT was limited by their desorption rate. Soils with more binding sites (higher DOM, CEC and Fe oxides) could resupply BPs more quickly, highlighting the danger of just considering partition effects.

Diffusive gradients in thin films: devices, materials and applications

“…The concentration of free form 4-chlorophenol obtained by MIP DGT decreased with the increasing concentration of dissolved organic carbon due to electrostatic interaction between 4-chlorophenol dissolved organic carbons. The concentrations of bisphenols (BPs) bisphenol A (BPA), bisphenol B (BPB) and bisphenol F (BPF) were measured in water and soils (Guan et al 2017;Zheng et al 2015). After 7 days of deployment, the BPs concentrations in water obtained by DGT were in good agreement with active sampling results.…”

“…Single solid binding phases are prepared by impregnating single binding agents (e.g., resin) into polyacrylamide or agarose gels (Guan et al 2017;Zhang et al 2004;Zheng et al 2015). In addition, some ion exchange membranes are directly used as single solid binding phases for measuring metals with DGT (Li et al 2002(Li et al , 2006.…”

“…Other available materials have also been reported for the determination of metals, such as adsorbent suspended particulate reagent-iminodiacetate (SPR-IDA) and activated carbon (Davison et al 1997;Lucas et al 2012Lucas et al , 2014. SPR-IDA and activated carbon DGT can measure fewer analytes than Chelex-100 but activated carbon DGT can be applied for Au and bisphenols (BPs) measurement over a wide range of pH and ionic strength conditions (Guan et al 2017;Lucas et al 2012;Warnken et al 2004a). Both Fig.…”

“…Compared with XAD-18 resin, the XAD-1 resin was suitable for application in high ionic strength environments (0.4-0.8 M), such as seawater. Activated charcoal DGT has also been employed for the simultaneous determination of bisphenols in water and soil, with performance not affected by pH within the range of 5-8, or ionic strengths between 0.001 and 0.5 M (Guan et al 2017;Zheng et al 2015). Ren et al (2018b) developed a novel binding phase using porous carbon material (PCM) as binding agent for measuring 20 antibiotics in water samples, and its measurement was independent of pH 4.2-8.4 and ionic strength 0.001-0.5 M NaCl.…”

“…APA gel is the most widely used diffusive layer and has been employed for the measurement of various cations and anions, with advantage of retaining stability in the range of pH 2-9 after hydrogel (Osterlund et al 2010;Wu et al 2014). Nevertheless, some studies have shown that the interactions between APA gel functional groups and target analytes, can result in inaccurate measurements, such as with Hg (Divis et al 2005;Pelcova et al 2015;Tafurt-Cardona et al 2015), Cu (Garmo et al 2008b), NH 4 + (Huang et al 2016c), and some organics (Guan et al 2017). APA gel possesses positive charge, therefore electrostatic interactions can interfere with metal diffusion at low ionic strengths according to the Donnan potential (Warnken et al 2005).…”