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In-situ sampling of chlorophenols in industrial wastewater using diffusive gradients in thin films technique based on mesoporous carbon

Meng, Zhuo, You, Nan, Fan, Hong-Tao
Chemosphere 2019 v.232 pp. 18-25
2,4,6-trichlorophenol, 2,4-dichlorophenol, 2-chlorophenol, carbon, diffusivity, equations, field experimentation, industrial wastewater, ionic strength, nylon, pH, porous media
In-situ sampling of 2-chlorophenol (CP), 2,4-dichlorophenol (DCP), and 2,4,6-trichlorophenol (TCP) in industrial wastewater was carried out by the diffusive gradients in thin films (DGT) device based on mesoporous carbon (MC). The diffusion coefficients of CP ((1.33 ± 0.05) × 10−6 cm2 s−1), DCP((1.35 ± 0.04) × 10−6 cm2 s−1) and TCP((1.09 ± 0.07) × 10−6 cm2 s−1)) in nylon membrane at 25 °C were independent of pH 3–9 and ionic strength as pNaCl from 0.155 to 3, and were less than their values in water, demonstrating that the nylon membrane with good tolerance and constant diffusion coefficients was suitable as the DGT diffusion layer for controlling the diffusion of CPs. MC-DGT accurately measured the concentrations of CP, DCP and TCP in synthetic solution (CDGT/CSOLN = 0.956–1.04) over the deployment of 120 h. The experimental data also agreed well with the theoretical data calculated on the DGT equation. The performance of MC-DGT for sampling CPs was independent of pH (3–8) and ionic strength as pNaCl (1.3–3) due to the change of the interaction between MC and CPs under relatively high pH and ionic strength. Deployments in laboratory and field trials demonstrated that the MC-DGT was a reliable simple, robust and accurate tool for the in-situ sampling of CP, DCP and TCP in the industrial wastewater.