Development Of A New Diffusive Gradients In Thin-films(DGT) Technique For Studying Bisphenols In Water And Soil

Widespread used of bisphenols(BPs)in our life results in their elevated concentrations in waters and the need to study their environmental impact,which demands reliable and robust measurement techniques.Diffusive gradients in thin films(DGT)is an in situ passive sampling approach which provides time-integrated data.In,this study we developed a new methodology,based on DGT with activated charcoal(AC)as a binding agent,for measuring three BPs(BPA,BPB and BPF)which incorporated and tested its performance characteristics.Consistent elution efficiencies were obtained using methanol when concentration of BPs were low and a methanol-NaOH mixture at high concentrations*The diffusion coefficients of BPA,BPB and BPF in tiv diffusive gel,measured using an independent diffusion cell,were 5.03 × 10-6,4.47 × 10-6 and 5.64 × 10-6 cm2/s at 25 ℃,respectively.DGT with an AC binding gel had a high capacity for BPA,BPB and BPF at 192,140 and 194 μg/binding gel disk,respectively,and the binding performance did not deteriorate with time,up to 254 d after production.Time-integrated concentrations of BPs measured in natural waters using DGT devices with AC gels deployed in situ for 7 d were comparable to concentrations measured by an active sampling method.This study demonstrates that AC-based DGT is an effective tool in situ monitoring of BPs in waters.Treated wastewater has been employed for irrigation of crops in many countries.Some bisphenols(BPs)including bisphenol A(BPA),bisphenol B(BPB)and bisphenol F(BPF)will enter the environment and react with soils.The behavior of sorption and desorption between BPs and soils affects their mobility and availability,which lead to risks to the environment.The kinetics of these process are still not well-known.Meanwhile,which factors affect these process and how they affect are also still not well-known.One passive sample method named diffusive gradients in thin-films(DGT)was deployed in fives soils with a wide range of soil texture for a range of times(2 h to 20 D)in this study to measure the partition coefficients and rates of exchange between solid phase and solution.The mass accumulated by DGT with activated charcoal gels was nonlinearly increased with deployment time.In this process,the concentration in the soil solution near DGT device was1.This cause a resupply from the solid phase to solution.To measure the distribution coefficients for lablie BPs(Kal)and the rate constant(response time To)for supply of BPs from solid phase to solution,a dynamic model of solute interaction called DIFS(DGT induced fluxes in soils)was used.All response time in this study is more than 18 min,which imply that the supply of BPS to DGT was limited by desorption release rate.The soils with more DOM could resupply BPs more quickly.The T,were 18,28 and 60 min for BPA,BPB and BPF in the soil with the highest concentration of DOM.However,they were 82,58 and 179 min for the soil with least DOM.As a result,DOM plays the most important role affect the ability of resupply BPs from solid phase to solution.