Microplastics and PFOA are emerging contaminants that are widely present in groundwater, posing threats to human health and ecosystems. This study aimed to investigate the remediation of polystyrene microplastics (PS-MPs) and perfluorooctanoic acid (PFOA) in groundwater using waste coconut shell biochar in permeable reactive barriers (PRBs). Fixed-bed column experiments were conducted with different bed depths, flow rates, initial pollutant concentrations, and co-contamination conditions. Results demonstrated that coconut shell biochar exhibited an effective adsorption capacity, with an initial concentration of 1 mg/L, flow rate of 0.5 mL/min, and bed depth of 2.5 mm, removal efficiencies of 75.00 % for PFOA and 36.24 % for PS-MPs were achieved within 10 days. Increasing the depth of biochar from 1.5 mm to 5.0 mm enhanced the removal efficiencies (PFOA:96.43 %, PS-MPs:61.72 %) and extended breakthrough times (480 min for PS-MPs, 2410 min for PFOA). Lower flow rates (0.2 mL/min) extended hydraulic retention time, improving adsorption (both PFOA and PS-MPs were > 75 %), while higher pollutant concentrations accelerate PRB depletion and reduce removal efficiency. Additionally, the presence of PS-MPs exhibited dual effects on PFOA remediation: promoting adsorption at low concentrations but causing competitive inhibition at high concentrations. Meanwhile, increasing PFOA concentrations intensified electrostatic repulsion, which reduced the removal efficiency of PS-MPs from 36.24 % to 10.43 % as the PFOA concentration increased from 0 to 10 mg/L. Furthermore, among the tested models (Thomas, Yoon-Nelson and BDST), the Thomas model best fitted the fixed-bed adsorption data for PS-MPs, PFOA, and composite contamination.
Adsorption-based separation of 2-phenylethanol (2-PE) and 1-phenylethanol (1-PE) is crucial yet challenging in the petrochemical industry. In this study, we report that an ultra-micropore aluminum-based metal–organic framework (Al-MOF) (i.e., CAU-23) exhibits higher 2-PE/1-PE selectivity (6.12) and 2-PE adsorption capacity (2.52 mmol g −1 ) in liquid phase compared to its pseudo-isostructural analogue of Al-MOFs, MIL-160 and MOF-303 at 293 K. The micropore diffusion model was employed to give the best fit to the adsorption kinetics of the CAU-23 with a rate achieved higher than MIL-160 and MOF-303. Computational analysis confirmed that 2-PE preferential adsorption stems from CAU-23′s well-matched pore geometry which enables efficient molecular confinement. In combination of inspecting the static adsorption properties of 2-PE and 1-PE onto CAU-23, we found that the superior affinity of CAU-23 toward 2-PE over 1-PE originates from entropy and enthalpy effect. The remarkable 2-PE/1-PE separation capability of CAU-23 was confirmed through breakthrough curve analysis (separation factor ≈ 4). As the first Al-MOF developed for 2-PE/1-PE separation, CAU-23 offers valuable insights into the design of advanced 2-PE-selective adsorbents.
危险品化学品经营许可证（带存储）