Hydroxyl Composite Material Catalyzed Hypochlorite Oxidation Treatment of 4-aminopyridine Wastewater

4-aminopyridine wastewater is characterized by high salt content, poor biodegradability, highly toxic and high chemical oxygen demand (COD) concentration. Hypochlorite oxidation is an advanced oxidation technology that shows unique advantages in treating alkaline pyridine compounds wastewater. In the present study, hydroxyl composites were prepared for the catalytic oxidation of calcium hypochlorite for the removal of 4-aminopyridine(4-AP). The preparation of hydroxyl composite materials is based on a 1:1 molar ratio of calcium hypochlorite to hexahydrate and nickel chloride. After centrifugation, the supernatant is removed, and the precipitate is sealed and stored in a refrigerator for future use. The composites were found to be structurally stable before and after the reaction, with irregular polyhedral shapes and mesoporous properties, as analyzed by a variety of characterization means. Under the optimal reaction conditions, i.e., 8 mL of hydroxyl composite, 3 g/L of Ca(ClO) 2 , and an initial pH value of 8–9, the removal rate of 4-AP was 93.3%. High concentrations of chloride, nitrate and carbonate (above 1 mmol/L) had no significant or only weak inhibitory effects on the reaction system. The main active substances in the system were 1 O₂ and ・O₂ − . The vulnerable sites of 4-AP were calculated to be N7 (f—= 0.1878), N1 (f—= 0.1367), C3,5 (f—= 0.0931). This research offers theoretical justification and technical guidance for addressing pesticide wastewater contaminated with 4-AP, and is expected to further expand the application of this system in the treatment of other difficult-to-degrade organic pollutants in the future. This study demonstrates significant practical application potential in industrial wastewater treatment, providing an efficient and stable method for degrading toxic pollutants. Its scientific value lies in elucidating the catalytic mechanism of hydroxyl composite materials and the action mechanism of reactive oxygen species, promoting the progress of environmental remediation technology.