郝慧茹,张倩,李孟,魏啸楠,仇玥.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[J].环境科学学报,2021,41(2):477-485
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
- Study on the mechanism and aging of modified biochar loaded nanoscale zero-valent iron activated persulfate to degrade Reactive Blue 19
- 基金项目：中央高校基本科研业务费专项基金资助项目（No.2019Ⅲ105CG）
- 郝慧茹
- 武汉理工大学土木工程与建筑学院, 武汉 430070
- 张倩
- 武汉理工大学土木工程与建筑学院, 武汉 430070
- 李孟
- 武汉理工大学土木工程与建筑学院, 武汉 430070
- 魏啸楠
- 武汉理工大学土木工程与建筑学院, 武汉 430070
- 仇玥
- 武汉理工大学土木工程与建筑学院, 武汉 430070
- 摘要：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—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）.nZVI@PBC表征结果表明，经磷酸改性后的生物炭具有更大的比表面积、更丰富的孔隙结构和活性官能团，有利于后续nZVI的负载及对污染物的降解.通过批次试验探究了nZVI@PBC投加量、PS浓度和初始pH值对nZVI@PBC/PS体系降解RB19的影响.结果表明，在RB19初始浓度为200 mg·L-1，pH值为4，PS浓度为2 mmol·L-1，nZVI@PBC投加量为0.1 g·L-1的条件下，反应60 min后nZVI@PBC/PS体系对RB19的降解率达到93.81%.自由基猝灭剂试验和电子顺磁共振（EPR）结果表明，SO4·-和·OH自由基均参与降解过程.nZVI@PBC/PS体系的活化机理为：nZVI首先与溶液中的O2、H2O、PS发生反应，生成具有活化能力的Fe（Ⅱ），随后Fe（Ⅱ）与PS发生非均相活化产生高活性的自由基.此外，探究了不同老化条件（包括置于水中、空气中及密封储存）对nZVI@PBC活性的影响.结果显示，在接触空气和密封储存的老化条件下并未对其活性产生显著影响，而水体环境对其活化性能破坏较严重.
- Abstract：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.
