改性生物炭负载纳米零价铁活化过硫酸盐降解活性蓝19的机理及老化研究

采用磷酸改性的黍糠基生物炭作为纳米零价铁(Nanoscale zero-valent iron,nZVI)载体,成功制备出一种高效非均相活化材料一磷酸改性生物炭负载纳米零价铁(nZVI@PBC),用来活化过硫酸盐(Persulfate,PS)降解印染废水中的典型染料—活性蓝(Reactive Blue 19,RB19)...

Study on the mechanism and aging of modified biochar loaded nanoscale zero-valent iron activated persulfate to degrade Reactive Blue 19

A highly efficient heterogeneous catalyst nZVI@PBC, serving as the carrier of nanoscale zero-valent iron (nZVI), was successfully prepared with phosphoric acid (H₃PO₄) modified bran-based biochar, which was used to activate persulfate (PS) for the degradation of Reactive Blue (RB19), the typical contaminant of dye wastewater. The characterization results indicated that nZVI@PBC had large specific surface area and pore structure and abundant functional groups after modified via H₃PO₄, which was conducive to the loading of nZVI and the degradation of RB19. The effect of nZVI@PBC dosage, PS concentration and initial pH on RB19 degradation was comprehensively investigated by the batch experiments, and the results suggested that RB19 removal could reach 93.81% after 60min, under the following condition: 200 mg·L^-1 of RB19 initial concentration, 2 mmol·L^-1 of PS concentration and pH=4. The results of radical scavenger experiments and EPR measurement showed that both SO₄^·- and ·OH participated in the RB19 degradation process. The degradation mechanism of RB19 in nZVI@PBC/PS system was mainly the heterogeneous activation of PS on the surface of iron-based species, the radical with high reactivity was generated by activating PS, and oxidized to degrade active blue 19. Furthermore, to explore the aging effect on nZVI@PBC performance, the aging tests were conducted under the condition of water, air and sealed storage, respectively. It was found that nZVI@PBC was relatively stable in air and sealed storage conditions, while its activation performance was severely damaged in the aqueous environment.