Highly selective removal of 2,4-dinitrotoluene for industrial wastewater treatment through hyper-cross-linked resins

Here a strategy by designing a series of hyper-cross-linked polystyrene resins (HCLRs) with highly selective adsorption ability toward hazardous 2,4-dinitrotoluene from nitrophenol sodium salt-rich real industrial wastewater was reported. Macroporous cross-linked chloromethylated polystyrene was self-crosslinked or crosslinked with ligands, i.e. toluene, aniline, and phenol to produce 2,4-dinitrotoluene affinitic HCLR-0, HCLR-T, HCLR-A and HCLR-P, respectively. The ultrahigh affinity through the like dissolves like mechanism toward 2,4-dinitrotoluene was validated by adsorption experiments, i.e. isotherm, kinetics, thermodynamics, effect of pH & 2-nitrophenol sodium salt and dynamic column adsorption-desorption investigations. They showed ultrahigh adsorption capacities toward 2,4-dinitrotoluene, reaching 628.9, 621.1, 657.9 and 641.0 mg/g for HCLR-0, HCLR-T, HCLR-A and HCLR-P at 303 K, out-performing their matrix cross-linked chloromethylated polystyrene of 79.2 mg/g and XAD-4 of 286 mg/g very much. This advantage was also reflected in the dynamic adsorption study with promising breakthrough and saturated capacities of 195.8 and 334.4 mg/mL wet HCLR-As, respectively. The HCLRs also featured interesting impurity affectless properties, in which 2-nitrophenol sodium salt showed no influence on the 2,4-dinitrotoluene capture even in high concentration. With the interesting properties shown above, the HCLR-A column worked very well in the large-scale real industrial wastewater, and could also be fully recycling used through simple low-cost treatment. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

A strategy involving the design of a series of highly selective hyper-cross-linked polystyrene resins (HCLRs) was reported for the selective adsorption of hazardous 2,4-dinitrotoluene from nitrophenol sodium salt-rich real industrial wastewater. The HCLRs demonstrated ultrahigh adsorption capacities towards 2,4-dinitrotoluene, outperforming other materials, and featured promising breakthrough and saturated capacities in dynamic adsorption studies.