过硫酸盐协同光催化纳米ZnO降解盐酸四环素的影响机制

以水葫芦为原料，制备了负载纳米ZnO的生物炭材料（ZnO-BC），研究了单独光催化ZnO-BC和过硫酸钠（PS）协同ZnO-BC/UV体系氧化降解盐酸四环素（TC）.结果表明，PS协同ZnO-BC /UV体系的降解反应速率比单独光催化ZnO-BC时有显著提高，120min后降解率达到89.48%.PS可作为强氧化剂，利用纳米ZnO的光生电子产生SO₄^-·和·OH协同光催化反应.TC的反应过程可分为两个阶段：暗吸附阶段和光催化反应阶段.影响因素和响应面试验结果得出的影响顺序为PS浓度 > 紫外灯功率 > 初始pH值 > 纳米ZnO质量浓度.猝灭试验表明，在TC的降解中，SO₄^-·和·OH是参与反应的主要自由基.起氧化作用的自由基一部分在溶液中产生，另一部分由生物炭材料表面含氧官能团的作用和紫外光激发纳米ZnO产生.在此基础上，探讨了在TC降解过程中，PS与ZnO-BC的协同机理和协同作用的规律.

Influence mechanism and synergistic effects of photocatalytic degradation of tetracycline hydrochloride by the combination of persulfate and nano-ZnO

In this paper, biochar loaded with nano-ZnO (ZnO-BC) was prepared from water hyacinth. The degradation performance of tetracycline hydrochloride (TC) in two systems, one referred to UV/ ZnO-BC system and the other to UV/ ZnO-BC /sodium persulfate (PS), were comparatively studied. The results showed that the degradation efficiency of ZnO-BC / UV system alongside PS was significantly higher than that of ZnO-BC alone, and the efficiency reached 89.48% after 120min. PS could be used as a strong oxidant that could use photogenerated electrons of nano-ZnO to produce SO₄-· and ·OH, achieving synergistic photocatalytic effects. The oxidation process of TC could be divided into two stages: dark adsorption and photocatalysis. The order of influence factors obtained by response surface methodology was PS concentration > UV power > initial pH value > nano-ZnO mass concentration. The quenching test suggested that SO₄-· and ·OH were the main free radicals in the degradation of TC. One part of the oxidizing free radicals were generated in the solution, the others from some kind of oxygen-containing functional groups on the biochar surface and the excitation of nano-ZnO by UV. On this basis, the synergistic mechanism and principle of PS and ZnO-BC during TC degradation were discussed.