Visible-light-driven removal of tetracycline antibiotics and reclamation of hydrogen energy from natural water matrices and wastewater by polymeric carbon nitride foam
Water and energy are key sustainability issues that need to be addressed. Photocatalysis represents an attractive means to not only remediate polluted waters, but also harness solar energy. Unfortunately, the employment of photocatalysts remains a practical challenge in terms of high cost, low effic...
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sg-ntu-dr.10356-1385602020-05-08T04:44:25Z Visible-light-driven removal of tetracycline antibiotics and reclamation of hydrogen energy from natural water matrices and wastewater by polymeric carbon nitride foam Wang, Hou Wu, Yan Feng, Mingbao Tu, Wenguang Xiao, Tong Xiong, Ting Ang, Huixiang Yuan, Xingzhong Chew, Jia Wei School of Chemical and Biomedical Engineering Nanyang Environment and Water Research Institute Engineering::Environmental engineering Resourcelization Photocatalysis Water and energy are key sustainability issues that need to be addressed. Photocatalysis represents an attractive means to not only remediate polluted waters, but also harness solar energy. Unfortunately, the employment of photocatalysts remains a practical challenge in terms of high cost, low efficiency, secondary pollution and unexploited water matrices influence. This study investigated the feasibility of photocatalysis to both treat water and produce hydrogen with practical water systems. Polymeric carbon nitride foam (CNF) with large surface area and mesoporous structure was successfully prepared via the bubble-template effect of ammonium chloride decomposition during thermal condensation. The reaction kinetics, mechanisms, and effect of natural water matrices and wastewater on CNF-based photocatalytic removal of tetracycline hydrochloride (TC-HCl) were systematically investigated. Furthermore, the efficiency of clean hydrogen energy from natural water matrices and wastewater was also evaluated. It was found that the photocatalytic performance of CNF for TC-HCl removal was principally affected by calcination temperature in the presence of NH4Cl. The degradation rates of CNF-4 (calcined at 550 °C) were approximately 1.84, 2.49 and 7.47 times than that of the CNF-2 (calcined at 600 °C), CNF-1 (calcined at 500 °C) and GCN (without NH4Cl), respectively. Results indicate that the improved photocatalytic performance was predominantly ascribed to the large specific surface area, increased availability of exposed active sites, and enhanced transport and separation efficiency of the photogenerated carrier. Based on electron spin resonance, chemical trapping experiment and density functional theory calculation, photoinduced oxidizing species (·O2- and holes) initially attacked the C-N-C fragment of TC molecules, which were finally mineralized to CO2, water and inorganic matters. Under the synergistic influence of water constituents (including acidity and alkalinity, ion species and dissolved organic substances), various water matrices greatly affected the degradation rate of TC-HCl, with the highest removal efficiency of 78.9% in natural seawater, followed by reservoir water (75.0%), tap water (62.3%), deionized water (49.8%), reverse osmosis concentrate (32.7%) and pharmaceutical wastewater (18.9%). Interestingly, low amounts of the emerging microplastics slightly improved TC-HCl removal, whereas high amounts (1.428 × 107 P/cm3) restricted removal due to light absorption and the intrinsic adsorption interaction. Moreover, the photocatalysts were able over repeated usage. Notably, the hydrogen yields rates of polymeric carbon nitride foam were 352.2, 299.8, 184.9 and 94.3 μmol/g/h in natural seawater, pharmaceutical wastewater, water from reservoir and tap water, respectively. This study proves the potential of novel nonmetal porous photocatalyst to simultaneously treat wastewater while converting solar energy into clean hydrogen energy. MOE (Min. of Education, S’pore) EDB (Economic Devt. Board, S’pore) 2020-05-08T04:44:25Z 2020-05-08T04:44:25Z 2018 Journal Article Wang, H., Wu, Y., Feng, M., Tu, W., Xiao, T., Xiong, T., . . . Chew, J. W. (2018). Visible-light-driven removal of tetracycline antibiotics and reclamation of hydrogen energy from natural water matrices and wastewater by polymeric carbon nitride foam. Water Research, 144, 215-225. doi:10.1016/j.watres.2018.07.025 0043-1354 https://hdl.handle.net/10356/138560 10.1016/j.watres.2018.07.025 30031366 2-s2.0-85052509665 144 215 225 en Water Research © 2018 Elsevier Ltd. All rights reserved. |
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Engineering::Environmental engineering Resourcelization Photocatalysis Wang, Hou Wu, Yan Feng, Mingbao Tu, Wenguang Xiao, Tong Xiong, Ting Ang, Huixiang Yuan, Xingzhong Chew, Jia Wei Visible-light-driven removal of tetracycline antibiotics and reclamation of hydrogen energy from natural water matrices and wastewater by polymeric carbon nitride foam |
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Water and energy are key sustainability issues that need to be addressed. Photocatalysis represents an attractive means to not only remediate polluted waters, but also harness solar energy. Unfortunately, the employment of photocatalysts remains a practical challenge in terms of high cost, low efficiency, secondary pollution and unexploited water matrices influence. This study investigated the feasibility of photocatalysis to both treat water and produce hydrogen with practical water systems. Polymeric carbon nitride foam (CNF) with large surface area and mesoporous structure was successfully prepared via the bubble-template effect of ammonium chloride decomposition during thermal condensation. The reaction kinetics, mechanisms, and effect of natural water matrices and wastewater on CNF-based photocatalytic removal of tetracycline hydrochloride (TC-HCl) were systematically investigated. Furthermore, the efficiency of clean hydrogen energy from natural water matrices and wastewater was also evaluated. It was found that the photocatalytic performance of CNF for TC-HCl removal was principally affected by calcination temperature in the presence of NH4Cl. The degradation rates of CNF-4 (calcined at 550 °C) were approximately 1.84, 2.49 and 7.47 times than that of the CNF-2 (calcined at 600 °C), CNF-1 (calcined at 500 °C) and GCN (without NH4Cl), respectively. Results indicate that the improved photocatalytic performance was predominantly ascribed to the large specific surface area, increased availability of exposed active sites, and enhanced transport and separation efficiency of the photogenerated carrier. Based on electron spin resonance, chemical trapping experiment and density functional theory calculation, photoinduced oxidizing species (·O2- and holes) initially attacked the C-N-C fragment of TC molecules, which were finally mineralized to CO2, water and inorganic matters. Under the synergistic influence of water constituents (including acidity and alkalinity, ion species and dissolved organic substances), various water matrices greatly affected the degradation rate of TC-HCl, with the highest removal efficiency of 78.9% in natural seawater, followed by reservoir water (75.0%), tap water (62.3%), deionized water (49.8%), reverse osmosis concentrate (32.7%) and pharmaceutical wastewater (18.9%). Interestingly, low amounts of the emerging microplastics slightly improved TC-HCl removal, whereas high amounts (1.428 × 107 P/cm3) restricted removal due to light absorption and the intrinsic adsorption interaction. Moreover, the photocatalysts were able over repeated usage. Notably, the hydrogen yields rates of polymeric carbon nitride foam were 352.2, 299.8, 184.9 and 94.3 μmol/g/h in natural seawater, pharmaceutical wastewater, water from reservoir and tap water, respectively. This study proves the potential of novel nonmetal porous photocatalyst to simultaneously treat wastewater while converting solar energy into clean hydrogen energy. |
author2 |
School of Chemical and Biomedical Engineering |
author_facet |
School of Chemical and Biomedical Engineering Wang, Hou Wu, Yan Feng, Mingbao Tu, Wenguang Xiao, Tong Xiong, Ting Ang, Huixiang Yuan, Xingzhong Chew, Jia Wei |
format |
Article |
author |
Wang, Hou Wu, Yan Feng, Mingbao Tu, Wenguang Xiao, Tong Xiong, Ting Ang, Huixiang Yuan, Xingzhong Chew, Jia Wei |
author_sort |
Wang, Hou |
title |
Visible-light-driven removal of tetracycline antibiotics and reclamation of hydrogen energy from natural water matrices and wastewater by polymeric carbon nitride foam |
title_short |
Visible-light-driven removal of tetracycline antibiotics and reclamation of hydrogen energy from natural water matrices and wastewater by polymeric carbon nitride foam |
title_full |
Visible-light-driven removal of tetracycline antibiotics and reclamation of hydrogen energy from natural water matrices and wastewater by polymeric carbon nitride foam |
title_fullStr |
Visible-light-driven removal of tetracycline antibiotics and reclamation of hydrogen energy from natural water matrices and wastewater by polymeric carbon nitride foam |
title_full_unstemmed |
Visible-light-driven removal of tetracycline antibiotics and reclamation of hydrogen energy from natural water matrices and wastewater by polymeric carbon nitride foam |
title_sort |
visible-light-driven removal of tetracycline antibiotics and reclamation of hydrogen energy from natural water matrices and wastewater by polymeric carbon nitride foam |
publishDate |
2020 |
url |
https://hdl.handle.net/10356/138560 |
_version_ |
1681058278302285824 |