Developing sustainable, metal-free advanced oxidation systems for antibiotic remediation remains a pressing environmental priority. Herein, a UV–visible-light-driven sodium percarbonate (SPC) activation strategy is proposed over the naturally abundant kaolinite synergistically regulated by mixed low-molecular-weight organic acids (oxalic, tartaric, and citric acids) for efficient tetracycline (TC) degradation. The integrated SPC/kaolinite/mixed-acid system achieved 93% TC removal in 45 min, markedly outperforming the individual acid-assisted systems. Structural analyses (XRD, FTIR, and XPS) confirmed preservation of the kaolinite lattice while revealing surface hydroxyl enrichment and interfacial complexation as key contributors to catalytic activity. Electron spin resonance and scavenger experiments demonstrated concurrent generation of •OH, O₂•−, CO₃•− and 1O₂, establishing a cooperative multi-reactive oxygen species oxidation pathway. Increasing surface electron density, decreasing charge transfer resistance and decreasing the probability of recombination by functionalizing surfaces utilizing mixed-acid conditions enhanced interfacial electron transfer of SPC through sustained decomposition of SPC without the need of metal-type catalysts. The system is quite effective in mild acidic pH and maintained substantial activity both in the presence of coexistent ions and real water matrices. Approximately, 67% TOC mineralization was achieved; toxicity modelling indicated progressive detoxification of the transformation products during oxidation. The findings provide mechanistic basis for microenvironment engineering for green SPC-based advanced oxidation processes targeting persistent pharmaceutical contaminants.