In this study, Cu-BTC, a kind of metal–organic framework, was used as an adsorbent to selectively adsorb methylene blue (abbreviated as MB) from dye mixed wastewater. The synthesized Cu-BTC was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results indicated that the synthesized Cu-BTC have an octahedral structure, with its specific surface area at 45.16 m²/g and the pore sizes at 35–40 nm. The influence of various parameters including the initial solution pH, temperature, ionic strength, initial concentration, and contact time on MB adsorption by Cu-BTC was investigated in detail. The adsorption capacity of Cu-BTC toward MB was optimized at the pH value of 8, with a lower temperature and a higher ionic strength. The adsorption isotherm was found to fit well with the Langmuir model, and the kinetic curve was found to be in good agreement with the pseudo-second-order kinetic model. The adsorption mechanism was revealed to be the combined effects of hydrophobicity and electrostatic adsorption. The synthesized Cu-BTC adsorption material showed great potential for recovering MB from dye-mixed wastewater.

As emerging pollutants, pharmaceutical and personal care products (PPCPs) have received extensive attention due to their high detection frequency (with concentrations ranging from ng/L to μg/L) and potential risk to aqueous environments and human health. Advanced oxidation processes (AOPs) are effective techniques for the removal of PPCPs from water environments. In AOPs, different types of free radicals (HO·, SO₄·⁻, O₂·⁻, etc.) are generated to decompose PPCPs into non-toxic and small-molecule compounds, finally leading to the decomposition of PPCPs. This review systematically summarizes the features of various AOPs and the removal of PPCPs by different free radicals. The operation conditions and comprehensive performance of different types of free radicals are summarized, and the reaction mechanisms are further revealed. This review will provide a quick understanding of AOPs for later researchers.