Dyeing wastewater poses a serious threat to environmental protection and industrial development.The piezoelectric effect can be used to optimize the band structure of semiconductors and improve the photon efficiency o...Dyeing wastewater poses a serious threat to environmental protection and industrial development.The piezoelectric effect can be used to optimize the band structure of semiconductors and improve the photon efficiency of photocatalysts.Bi_(2)Fe_(4)O_(9),a narrow gap semiconductor with piezoelectric effect,was prepared by a hydrothermal synthesis method for the degradation of reactive dye KN-R.The results show that the degradation efficiency of KN-R can be significantly improved by piezo-photocatalysis,and the degradation rate constant of piezo-photocatalysis k_(pi-ph)is about 3.4 times as large as the degradation rate constant of piezoelectric catalysis k_(pi)and about 2.6 times as large as the degradation rate constant of photocatalysis k_(ph).At a pH value of 3 and a lower KN-R mass concentration(60 mg/L),a higher degradation efficiency(98.5%)is achieved.CO_(3)^(2-)and cationic surfactant(CTAB)inhibit the degradation of KN-R.It is proved that the contributions of different active species to the degradation of KN-R follow the order:·OH,·O_(2)^(-),h^(+),and^(1)O_(2).The possible mechanism of piezo-photocatalytic degradation of KN-R was discussed.The photoexcitation generates a large amount of free charges,and the piezoelectric effect modulates the energy band structure of Bi_(2)Fe_(4)O_(9)and promotes the separation of photogenerated electron-hole pairs.The synergistic effect of the two factors significantly improves the degradation efficiency of KN-R.展开更多
利用过水解酶催化合成过氧乙酸,过氧乙酸原位氧化活性艳蓝KN-R脱色.在单因子试验的基础上,通过正交优化试验确定活性艳蓝KN-R的最佳脱色条件为:在5 m L反应体系中,最适p H 5.0,加酶量为20 U·反应-1,乙酸乙酯对过氧化氢的摩尔比率...利用过水解酶催化合成过氧乙酸,过氧乙酸原位氧化活性艳蓝KN-R脱色.在单因子试验的基础上,通过正交优化试验确定活性艳蓝KN-R的最佳脱色条件为:在5 m L反应体系中,最适p H 5.0,加酶量为20 U·反应-1,乙酸乙酯对过氧化氢的摩尔比率为40∶1和活性艳蓝KNR的浓度为80 mg·L-1.在此条件下反应6 h后,活性艳蓝KN-R的脱色率为81.11%,24 h后的脱色率为91.96%.在50倍放大试验中,该工艺24小时的脱色率为84.55%.展开更多
文摘Dyeing wastewater poses a serious threat to environmental protection and industrial development.The piezoelectric effect can be used to optimize the band structure of semiconductors and improve the photon efficiency of photocatalysts.Bi_(2)Fe_(4)O_(9),a narrow gap semiconductor with piezoelectric effect,was prepared by a hydrothermal synthesis method for the degradation of reactive dye KN-R.The results show that the degradation efficiency of KN-R can be significantly improved by piezo-photocatalysis,and the degradation rate constant of piezo-photocatalysis k_(pi-ph)is about 3.4 times as large as the degradation rate constant of piezoelectric catalysis k_(pi)and about 2.6 times as large as the degradation rate constant of photocatalysis k_(ph).At a pH value of 3 and a lower KN-R mass concentration(60 mg/L),a higher degradation efficiency(98.5%)is achieved.CO_(3)^(2-)and cationic surfactant(CTAB)inhibit the degradation of KN-R.It is proved that the contributions of different active species to the degradation of KN-R follow the order:·OH,·O_(2)^(-),h^(+),and^(1)O_(2).The possible mechanism of piezo-photocatalytic degradation of KN-R was discussed.The photoexcitation generates a large amount of free charges,and the piezoelectric effect modulates the energy band structure of Bi_(2)Fe_(4)O_(9)and promotes the separation of photogenerated electron-hole pairs.The synergistic effect of the two factors significantly improves the degradation efficiency of KN-R.
文摘利用过水解酶催化合成过氧乙酸,过氧乙酸原位氧化活性艳蓝KN-R脱色.在单因子试验的基础上,通过正交优化试验确定活性艳蓝KN-R的最佳脱色条件为:在5 m L反应体系中,最适p H 5.0,加酶量为20 U·反应-1,乙酸乙酯对过氧化氢的摩尔比率为40∶1和活性艳蓝KNR的浓度为80 mg·L-1.在此条件下反应6 h后,活性艳蓝KN-R的脱色率为81.11%,24 h后的脱色率为91.96%.在50倍放大试验中,该工艺24小时的脱色率为84.55%.
