In order to solve the problem that the traditional biochar(BC) has insufficient removal ability of enrofloxacin and TiO₂ is difficult to recycle. In this study, TiO₂-modified biochar composites were prepared by impregnation method. Through characterization analysis, The BET specific surface area results indicated that after loading TiO₂, the specific surface area of TiO₂-biochar(Ti-BC), TiO₂-ironized biochar(Ti-FBC) and TiO₂-alkaline biochar(Ti-KBC) increased by 4.34, 10.43 and 11.52 times, respectively. The analysis results of SEM, EDS, FT-IR, XRD and XPS showed that TiO₂ was supported on biochar in the anatase state. The UV-vis DRS measurement showed that the band width of Ti-KBC was the smallest and the best catalytic activity. Under 15 W UV lamp (254 nm) irradiation, the photocatalytic degradation process of enrofloxacin by different biochar accords with the first-order kinetic equation. Ti-KBC showed best degradation effect under different initial concentrations of enrofloxacin. When the pH of the solution was 5.0 and the dosage of Ti-KBC was at 2.5 g·L⁻¹, the enrofloxacin degradation rate of 100 mg·L⁻¹ reached 85.25%. The quenching test confirmed that the active substance O₂•^— played a major role in the photocatalytic degradation process. After five cycles of the test, the degradation rate of Ti-KBC for enrofloxacin was 77.14%, which was still better than that of BC, Ti-BC and Ti-FBC.

The levels of enrofloxacin have exceeded acceptable standards in the water environment of many global regions, and the problem of pollution caused by enrofloxacin needs to be solved urgently. In this study, phosphoric acid and potassium hydroxide were used to modify corn stalk biochar. The properties and structure of the modified biochar were studied by scanning electron microscopy, infrared spectrometer, X-ray diffraction spectroscopy, and other analytical methods. Other factors influencing enrofloxacin adsorption were assessed using the equilibrium adsorption method. The surface area of the acid- and alkali-modified biochar was found to increase 10- and 14-fold, respectively. The equilibrium adsorption capacity of enrofloxacin on the acid- and alkali-modified biomass carbon increased by 27.80% and 54.08%, respectively. The quasi-second-order kinetic equation and Langmuir equation described the adsorption process of the biochars accurately. At pH = 5.0, the biochars had the highest levels of enrofloxacin adsorption. The adsorption of enrofloxacin onto the biochars negatively correlated with the concentration of Ca²⁺ in the background solution.

Due to the norfloxacin will enter the natural water body with the effluent of the sewage treatment plant and cause water environment pollution, the research on how to effectively remove norfloxacin has become a hot topic. This experiment used hydrochloric acid and sodium hydroxide to study the modification of fly ash. The structure characteristics and properties of modified fly ash were determined by scanning electron microscope, X-ray diffractometer and infrared spectrometer, and the adsorption process of norfloxacin by fly ash was analyzed. It was found that the surface of fly ash modified by acid and alkali was rougher and the voids increased, which provided a rich adsorption site for the adsorption reaction of norfloxacin on fly ash, moreover, the specific surface area of sodium hydroxide modified fly ash increased the most, and the ability to adsorb norfloxacin was the strongest. The adsorption process characteristics showed that the adsorption reaction of norfloxacin is spontaneous, exothermic, disordered, and when the temperature increased, the adsorption amount of norfloxacin by fly ash was decreased, and the adsorption effect of fly ash on norfloxacin was the strongest under the pH = 7.0, yet inhibited when the adding of Ca²⁺ in the solution.

In this study, the effects of temperature, pH, and biochar under cadmium stress on the adsorption characteristics of atrazine in soils in northeast China were studied by batch adsorption method. In the atrazine–Cd(II) coexistence system, the adsorption of atrazine by the soils reached equilibrium within 24 h, but there were some differences in sorption capacities of the three types of soil and the order of adsorption is albic soil > black soil > saline-alkaline soil. With the concentration of atrazine increased, the adsorption capacity of atrazine in the three types of soil gradually increased, the upward trend became more obvious with the ambient temperature of the solution decreased. The adsorption kinetics curves of atrazine in the three types of soil conform to the pseudo-second-order kinetic model and the adsorption isotherm follows the Langmuir model. When atrazine and Cd(II) coexist in soils, the decrease in atrazine adsorption in the soil may be due to the competitive interaction between the two chemicals. Cd(II) occupies part of the adsorption site of atrazine, thus saturating the active site in soils. Since atrazine is a weakly alkaline pesticide, the lower the pH of the soil, the higher the affinity of atrazine for the soil. After adding biochar to the soil, the functional groups in biochar can form π bond with atrazine, which promotes the fixation of atrazine in the soil. The results show that the prevention of atrazine and cadmium leaching can be achieved by appropriately adjusting the pH, temperature, clay content, and organic matter of the soils.