The photocatalytic degradation of sulfamethoxazole (SMX), sulfadiazine (SDZ) and sulfamethazine (SMT) by Bi₂O₃-TiO₂/PAC under solar light irradiation was studied. The results exhibited that Bi₂O₃-TiO₂/PAC composite prepared by two-stage calcination method contained of rutile and anatase mixed crystal phases, and it had visible light response capability. In addition, Bi₂O₃-TiO₂/PAC had a certain adsorption capacity for SMX, SDZ and SMT, and its saturated adsorption mass was 30.88, 11.28 and 26.24 mg/g, respectively. Compared to photolysis and adsorption process, the photocatalytic degradation efficiencies of the three sulfonamides were significantly improved, and more than 99 % of photocatalytic degradation efficiency was achieved. The EPR measurements showed that both hydroxyl radicals (·OH) and superoxide radicals (·O₂⁻) were produced in the photocatalytic process. However, trapping experiments confirmed that photo-generated hole (h⁺) played a lead role in the photocatalytic degradation of SMX. Contrarily, the ·O₂- was the main oxidative species for SDZ and SMT degradation. Furthermore, the effects of initial pH of solution, sodium bicarbonate, humic acid and natural water (lake and river water) on the photocatalytic degradation were investigated. The photocatalytic degradation pathways of Bi₂O₃-TiO₂/PAC for sulfonamides were discussed. There were differences degradation pathways of the SDZ, SMT and SMX by Bi₂O₃-TiO₂/PAC mainly reflected in: Hydroxylation of benzene ring, extrusion of SO₂. While, similar pathways existed in the process of sulfanilamide degradation, such as the breaking of SN bond and the cracking of N-containing benzene ring.

研究了Bi ₂ O ₃ -TiO ₂ / PAC在太阳光照射下对磺胺甲恶唑（SMX），磺胺嘧啶（SDZ）和磺胺二甲嘧啶（SMT）的光催化降解。结果表明，两阶段煅烧法制备的Bi ₂ O ₃ -TiO ₂ / PAC复合材料含有金红石和锐钛矿混合晶相，具有可见光响应能力。另外，Bi ₂ O ₃ -TiO ₂/ PAC对SMX，SDZ和SMT具有一定的吸附能力，其饱和吸附质量分别为30.88、11.28和26.24 mg / g。与光解和吸附过程相比，三种磺酰胺的光催化降解效率都有明显提高，光催化降解效率达到99％以上。所述EPR测量结果表明，这两个羟基自由基（·OH）和超氧自由基（·O2 ₂ ^- ）在光催化过程中产生的。但是，诱捕实验证实，光生空穴（h ⁺）在SMX的光催化降解中起主导作用。相反，·O ₂-是SDZ和SMT降解的主要氧化物质。此外，研究了溶液的初始pH，碳酸氢钠，腐殖酸和天然水（湖水和河水）对光催化降解的影响。讨论了Bi ₂ O ₃ -TiO ₂ / PAC对磺酰胺的光催化降解途径。Bi ₂ O ₃ -TiO ₂ / PAC对SDZ，SMT和SMX的降解途径存在差异，主要表现在：苯环的羟基化，SO _2的挤出。同时，在磺酰胺降解过程中存在相似的途径，例如S N键的断裂和含N苯环的裂解。