[1] Xu Yiqiao, Wu Lei, Zheng Tianyi, Nitrate reduction by·CO-2 from UV-activated HCOOH [J]. Journal of Southeast University (English Edition), 2022, 38 (1): 77-84. [doi:10.3969/j.issn.1003-7985.2022.01.012]
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Nitrate reduction by·CO-2 from UV-activated HCOOH(
)
基于紫外光活化甲酸产生二氧化碳自由基的硝态氮还原分析
)Journal of Southeast University (English Edition)[ISSN:1003-7985/CN:32-1325/N]
- Volumn:
- 38
- Issue:
- 2022 1
- Page:
- 77-84
- Research Field:
- Environmental Science and Engineering
- Publishing date:
- 2022-03-20
Info
- Title:
- Nitrate reduction by·CO-2 from UV-activated HCOOH
- 基于紫外光活化甲酸产生二氧化碳自由基的硝态氮还原分析
- Author(s):
- Xu Yiqiao1; Wu Lei1; Zheng Tianyi1; 2
-
1School of Energy and Environment, Southeast University, Nanjing 210096, China
2Jiangsu Branch of China Municipal Engineering Northwest Design and Research Institute Co., Ltd., Nanjing 210017, China
- Keywords:
- nitrate reduction; advanced reduction process; ultraviolet; HCOOH; ·CO-2
- PACS:
- X52
- DOI:
- 10.3969/j.issn.1003-7985.2022.01.012
- Abstract:
- To address the environmental and health hazards of nitrate(NO-3)in water, a denitrification advanced reduction process(ARP)using only formic acid(HCOOH)activated by ultraviolet(UV)light was proposed. The efficiency, influencing factors, mechanism, and kinetics of the reduction were investigated through component analysis and radical detection. Results show that, after 90 min of UV illumination, the reduction and gas conversion ratios of 50 mg/L NO-3-N reach 99.9% and 99.8%, respectively, under 9 mM of C0(HCOOH), pH = 3.0, and N2 aeration. Meanwhile, 96.7% of HCOOH is consumed and converted into gas. The NO-3-N conversion process includes the transformation to NO-2-N, followed by a further reduction to gas and a direct conversion into gas, introducing small amounts of nitrite and ammonia. The carbon dioxide anion radical(·CO-2)from HCOOH/HCOO- is the principal cause of NO-3-N reduction by UV/HCOOH/N2 ARP. In contrast, ·CO-2 production is caused by the hydroxyl radical(·OH). The NO-3-N reduction efficiency is enhanced by the increase in the light intensity, considerably affected by the initial pH, and less affected by inorganic anions, including Cl-, H2PO-4, and HCO-3/CO2-3. The initial HCOOH concentration and light intensity are the main factors that influence the NO-3-N reduction rate.
- 为解决水中硝态氮引发的环境和健康问题, 提出了一种以甲酸为还原剂、以紫外光为活化手段的硝态氮还原(ARP)方法. 通过组分分析和自由基测定研究了体系的还原效能、影响因素、反应机理及反应动力学. 结果表明:在C0(HCOOH)= 9 mmol/L、初始pH = 3.0和N2曝气条件下, 紫外光照90 min后50 mg/L硝态氮的还原率和气体转化率分别达到99.9%和99.8%, 同时96.7%的甲酸被消耗并转化为气体. 该体系还原硝态氮的反应中不仅存在首先生成亚硝态氮再进一步被还原为气体的过程, 还存在硝态氮直接转化为气体的过程.硝态氮的还原主要由活化HCOOH/HCOO-产生的二氧化碳自由基(·CO-2)实现, 而羟基自由基(·OH)是·CO-2的前体物. 硝态氮还原率随光照强度增加而提高, 初始pH值对还原效果影响较大, 而Cl-、H2PO-4和HCO-3/CO2-3等无机阴离子的影响则较小.甲酸初始浓度和紫外光强是还原速率的主要影响因素.
References:
[1] Pacheco F A L, Santos R M B, Fernandes L F S, et al. Controls and forecasts of nitrate yields in forested watersheds: A view over mainland Portugal[J]. Science of the Total Environment, 2015, 537: 421-440. DOI: 10.1016/j.scitotenv.2015.07.127.
[2] Huno S K M, Rene E R, Van Hullebusch E D, et al. Nitrate removal from groundwater: A review of natural and engineered processes[J]. Journal of Water Supply: Research and Technology—Aqua, 2018, 67(8): 885-902. DOI: 10.2166/aqua.2018.194.
[3] Blarasin M, Cabrera A, Matiatos I, et al. Comparative evaluation of urban versus agricultural nitrate sources and sinks in an unconfined aquifer by isotopic and multivariate analyses[J]. Science of the Total Environment, 2020, 741: 140374. DOI: 10.1016/j.scitotenv.2020.140374.
[4] Chen N W, Peng B R, Hong H S, et al. Nutrient enrichment and N:P ratio decline in a coastal bay-river system in southeast China: The need for a dual nutrient(N and P)management strategy[J]. Ocean & Coastal Management, 2013, 81: 7-13. DOI: 10.1016/j.ocecoaman.2012.07.013.
[5] Dan-Hassan M A, Olasehinde P I, Amadi A N, et al. Spatial and temporal distribution of nitrate pollution in groundwater of Abuja, Nigeria[J]. International Journal of Chemistry, 2012, 4(3): 104-112. DOI: 10.5539/ijc.v4n3p104.
[6] Lotfata A, Ambinakudige S. Factors affecting the spatial pattern of nitrate contamination in Texas aquifers[J]. Management of Environmental Quality: An International Journal, 2019, 31(4): 857-876. DOI: 10.1108/MEQ-05-2019-0097.
[7] Vystavna Y, Diadin D, Grynenko V, et al. Determination of dominant sources of nitrate contamination in transboundary(Russian Federation/Ukraine)catchment with heterogeneous land use[J]. Environ Monit Assess, 2017, 189: 509. DOI: 10.1007/s10661-017-6227-5.
[8] Yan B Z, Xiao C L, Liang X J, et al. Impacts of urban land use on nitrate contamination in groundwater, Jilin City, Northeast China[J].Arabian Journal of Geosciences, 2016, 9(2): 105. DOI: 10.1007/s12517-015-2052-8.
[9] Liu Y, Wang J L. Reduction of nitrate by zero valent iron(ZVI)-based materials: A review[J]. Sci Total Environ, 2019, 671: 388-403. DOI: 10.1016/j.scitotenv.2019.03.317.
[10] Wang B Q, An B H, Liu Y, et al. Selective reduction of nitrate into nitrogen at neutral pH range by iron/copper bimetal coupled with formate/ferric ion and ultraviolet radiation[J]. Separation and Purification Technology, 2020, 248: 117061. DOI: 10.1016/j.seppur.2020.117061.
[11] Liu H, Liu X Y, Yang W W, et al. Photocatalytic dehydrogenation of formic acid promoted by a superior PdAg@g-C3N4 Mott-Schottky heterojunction[J]. Journal of Materials Chemistry A, 2019, 7(5): 2022-2026. DOI: 10.1039/c8ta11172c.
[12] Jung B, Safan A, Duan Y, et al. Removal of arsenite by reductive precipitation in dithionite solution activated by UV light[J]. Journal of Environmental Sciences, 2018, 74: 168-176. DOI: 10.1016/j.jes.2018.02.023.
[13] Xiao Q, Wang T, Yu S L, et al. Influence of UV lamp, sulfur(IV)concentration, and pH on bromate degradation in UV/sulfite systems: Mechanisms and applications[J]. Water Research, 2017, 111: 288-296. DOI: 10.1016/j.watres.2017.01.018.
[14] Bensalah N, Nicola R, Abdel-Wahab A. Nitrate removal from water using UV-M/S2O2-4 advanced reduction process[J]. International Journal of Environmental Science and Technology, 2013, 11(6): 1733-1742. DOI: 10.1007/s13762-013-0375-0.
[15] An B H, He H N, Duan B H, et al. Selective reduction of nitrite to nitrogen gas by CO2 anion radical from the activation of oxalate[J]. Chemosphere, 2021, 278: 130388. DOI: 10.1016/j.chemosphere.2021.130388.
[16] Tugaoen H O, Garcia-Segura S, Hristovski K, et al. Challenges in photocatalytic reduction of nitrate as a water treatment technology[J]. Science of the Total Environment, 2017, 599-600: 1524-1551. DOI: 10.1016/j.scitotenv.2017.04.238.
[17] Gu X G, Lu S G, Fu X R, et al. Carbon dioxide radical anion-based UV/S2O2-8/HCOOH reductive process for carbon tetrachloride degradation in aqueous solution[J]. Separation and Purification Technology, 2017, 172: 211-216. DOI: 10.1016/j.seppur.2016.08.019.
[18] Chen J L, Liu J Y, Zhou J S, et al. Reductive removal of nitrate by carbon dioxide radical with high product selectivity to form N2 in a UV/H2O2/HCOOH system[J]. Journal of Water Process Engineering, 2020, 33:101097. DOI: 10.1016/j.jwpe.2019.101097.
[19] Harbour J R, Hair M L. Spin trapping of the ·CO-2 radical in aqueous medium[J]. Canadian Journal of Chemistry, 2011, 57(10): 1150-1152. DOI: 10.1139/v79-188.
[20] Cheng S A, Fung W K, Chan K Y, et al. Optimizing electron spin resonance detection of hydroxyl radical in water[J]. Chemosphere, 2003, 52(10): 1797-1805. DOI: 10.1016/s0045-6535(03)00369-2.
[21] Han S K, Hwang T M, Yoon Y, et al. Evidence of singlet oxygen and hydroxyl radical formation in aqueous goethite suspension using spin-trapping electron paramagnetic resonance(EPR)[J].Chemosphere, 2011, 84(8): 1095-1101. DOI: 10.1016/j.chemosphere.2011.04.051.
[22] Augusto O, Bonini M G, Amanso A M, et al. Nitrogen dioxide and carbonate radical anion: Two emerging radicals in biology[J]. Free Radical Biology and Medicine, 2002, 32(9): 841-859. DOI: 10.1016/S0891-5849(02)00786-4.
[23] Draganic Z D, Negronmendoza A, Sehested K, et al. Radiolysis of aqueous-solutions of ammonium bicarbonate over a large dose range[J]. Radiation Physics and Chemistry, 1991, 38(3): 317-321. DOI:10.1016/1359-0197(91)90100-G.
Memo
- Memo:
-
Biographies: Xu Yiqiao(1998—), female, graduate; Wu Lei(corresponding author), male, associate professor, wulei@seu.edu.cn.
Foundation item: The National Major Science and Technology Project(No.2017ZX07202-004-005).
Citation: Xu Yiqiao, Wu Lei, Zheng Tianyi.Nitrate reduction by ·CO-2 from UV-activated HCOOH[J].Journal of Southeast University(English Edition), 2022, 38(1):77-84.DOI:10.3969/j.issn.1003-7985.2022.01.012.