以葡萄籽提取液合成纳米铁粒子,将其与过氧化氢(H_2O_2)联用类芬顿法降解水中的酸性大红(AR)。考察了H_2O_2加入量、AR初始浓度、温度和pH对降解效果的影响。结果表明,AR降解率随AR初始浓度的降低,温度的升高,pH的降低而提高;在5～30 m ...以葡萄籽提取液合成纳米铁粒子,将其与过氧化氢(H_2O_2)联用类芬顿法降解水中的酸性大红(AR)。考察了H_2O_2加入量、AR初始浓度、温度和pH对降解效果的影响。结果表明,AR降解率随AR初始浓度的降低,温度的升高,pH的降低而提高;在5～30 m L内,H_2O_2(10%)加入量20 m L时AR降解率最高。在pH值3～9,经反应180 min后,AR的降解率均可达到90%以上,说明pH值对AR降解的影响不显著。分别采用伪一级、伪二级、层间扩散模型对酸性大红降解的动力学行为进行描述,结果显示伪二级模型(R2=0. 998)对实验数据的拟合度最好,活化能为23. 7 k J/mol。展开更多
Nanoscale iron particles （nZVI） is one of the most important engineered nanomaterials applied to environmental pollution control and abatement. Although a multitude of synthesis approaches have been proposed, a faci...Nanoscale iron particles （nZVI） is one of the most important engineered nanomaterials applied to environmental pollution control and abatement. Although a multitude of synthesis approaches have been proposed, a facile method to screen the reactivity of candidate nZVI materials produced using different methods or under varying synthesis conditions has yet been established. In this study, four reaction parameters were adjusted in the preparation of borohydride-reduced nZVI. The reductive properties of the resultant nanoparticles were assayed independently using two model aqueous contaminants, Cu （II） and nitrate. The results confirm that the reductive reactivity of nZVI is most sensitive to the initial concentration of iron precursor, borohydride feed rate, and the loading ratio of borohydride to ferric ion during particle synthesis. Solution mixing speed, in contrast, carries a relative small weight on the reactivity of nZVI. The two probing reactions （i.e., Cu（II） and nitrate reduction） are able to generate consistent and quantitative inference about the mass-normalized surface activity of nZVI. However, the nitrate assay is valid in dilute aqueous solutions only （50 mg.L~ or lower） due to accelerated deactivation of iron surface at elevated nitrate concentra- tions. Additional insights including the structural and chemical makeup of nZVI can be garnered from Cu（II） reduction assessments. The reactivity assays investigated in this study can facilitate screening of candidate materials or optimization of nZVI production parameters, which complement some of the more sophisticated but less chemically specific material characterization methods used in the nZVI research.展开更多
文摘以葡萄籽提取液合成纳米铁粒子,将其与过氧化氢(H_2O_2)联用类芬顿法降解水中的酸性大红(AR)。考察了H_2O_2加入量、AR初始浓度、温度和pH对降解效果的影响。结果表明,AR降解率随AR初始浓度的降低,温度的升高,pH的降低而提高;在5～30 m L内,H_2O_2(10%)加入量20 m L时AR降解率最高。在pH值3～9,经反应180 min后,AR的降解率均可达到90%以上,说明pH值对AR降解的影响不显著。分别采用伪一级、伪二级、层间扩散模型对酸性大红降解的动力学行为进行描述,结果显示伪二级模型(R2=0. 998)对实验数据的拟合度最好,活化能为23. 7 k J/mol。
文摘Nanoscale iron particles （nZVI） is one of the most important engineered nanomaterials applied to environmental pollution control and abatement. Although a multitude of synthesis approaches have been proposed, a facile method to screen the reactivity of candidate nZVI materials produced using different methods or under varying synthesis conditions has yet been established. In this study, four reaction parameters were adjusted in the preparation of borohydride-reduced nZVI. The reductive properties of the resultant nanoparticles were assayed independently using two model aqueous contaminants, Cu （II） and nitrate. The results confirm that the reductive reactivity of nZVI is most sensitive to the initial concentration of iron precursor, borohydride feed rate, and the loading ratio of borohydride to ferric ion during particle synthesis. Solution mixing speed, in contrast, carries a relative small weight on the reactivity of nZVI. The two probing reactions （i.e., Cu（II） and nitrate reduction） are able to generate consistent and quantitative inference about the mass-normalized surface activity of nZVI. However, the nitrate assay is valid in dilute aqueous solutions only （50 mg.L~ or lower） due to accelerated deactivation of iron surface at elevated nitrate concentra- tions. Additional insights including the structural and chemical makeup of nZVI can be garnered from Cu（II） reduction assessments. The reactivity assays investigated in this study can facilitate screening of candidate materials or optimization of nZVI production parameters, which complement some of the more sophisticated but less chemically specific material characterization methods used in the nZVI research.
