Simultaneous removal of NOx and chlorobenzene on V2O5/TiO2 granular catalyst: Kinetic study and performance prediction

• A V₂O₅/TiO₂ granular catalyst for simultaneous removal of NO and chlorobenzene. • Catalyst synthesized by vanadyl acetylacetonate showed good activity and stability. • The kinetic model was established and the synergetic activity was predicted. • Both chlorobenzene oxidation and SCR of NO follow pseudo-first-order kinetics. • The work is of much value to design of multi-pollutants emission control system. The synergetic abatement of multi-pollutants is one of the development trends of flue gas pollution control technology, which is still in the initial stage and facing many challenges. We developed a V₂O₅/TiO₂ granular catalyst and established the kinetic model for the simultaneous removal of NO and chlorobenzene (i.e., an important precursor of dioxins). The granular catalyst synthesized using vanadyl acetylacetonate precursor showed good synergistic catalytic performance and stability. Although the SCR reaction of NO and the oxidation reaction of chlorobenzene mutually inhibited, the reaction order of each reaction was not considerably affected, and the pseudo-first-order reaction kinetics was still followed. The performance prediction of this work is of much value to the understanding and reasonable design of a catalytic system for multi-pollutants (i.e., NO and dioxins) emission control.     

NiB2O4 (B = Mn or Co) catalysts for NH3-SCR of NOx at low-temperature in microwave field

● Microwave-assisted catalytic NH₃-SCR reaction over spinel oxides is carried out. ● SCR reaction temperature is tremendously lowered in microwave field. ● NO conversion of NiMn₂O₄ is highly up to 90.6% at 70°C under microwave heating. Microwave-assisted selective catalytic reduction of nitrogen oxides (NO_x) was investigated over Ni-based metal oxides. The NiMn₂O₄ and NiCo₂O₄ catalysts were synthesized by the co-precipitation method and their activities were evaluated as potential candidate catalysts for low-temperature NH₃-SCR in a microwave field. The physicochemical properties and structures of the catalysts were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), N₂-physisorption, NO adsorption-desorption in the microwave field, H₂-temperature programmed reduction (H₂-TPR) and NH₃-temperature programmed desorption (NH₃-TPD). The results verified that microwave radiation reduced the reaction temperature required for NH₃-SCR compared to conventional heating, which needed less energy. For the NiMn₂O₄ catalyst, the catalytic efficiency exceeded 90% at 70 °C and reached 96.8% at 110 °C in the microwave field. Meanwhile, the NiMn₂O₄ also exhibited excellent low-temperature NH₃-SCR reaction performance under conventional heating conditions, which is due to the high BET specific surface area, more suitable redox property, good NO adsorption-desorption in the microwave field and rich acidic sites.     

CeO2 doping boosted low-temperature NH3-SCR activity of FeTiOx catalyst: A microstructure analysis and reaction mechanistic study

• CeO₂ doping significantly improved low-temperature NH₃-SCR activity on FeTiO_x. • The crystallinity of FeTiO_x was decreased dramatically after CeO₂ doping. • Unique Ce-O-Fe structure in FeCe_0.2TiO_x accounted for its superior redox property. • Facile activation of NH₃ to-NH₂ on FeCe_0.2TiO_x promoted the DeNO_x efficiency. FeTiO_x has been recognized as an environmental-friendly and cost-effective catalyst for selective catalytic reduction (SCR) of NO_x with NH₃. Aimed at further improving the low-temperature DeNO_x efficiency of FeTiO_x catalyst, a simple strategy of CeO₂ doping was proposed. The low-temperature (<250℃) NH₃-SCR activity of FeTiO_x catalyst could be dramatically enhanced by CeO₂ doping, and the optimal composition of the catalyst was confirmed as FeCe_0.2TiO_x, which performed a NO_x conversion of 90% at ca. 200℃. According to X-ray diffraction (XRD), Raman spectra and X-ray absorption fine structure spectroscopy (XAFS) analysis, FeCe_0.2TiO_x showed low crystallinity, with Fe and Ce species well mixed with each other. Based on the fitting results of extended X-ray absorption fine structure (EXAFS), a unique Ce-O-Fe structure was formed in FeCe_0.2TiO_x catalyst. The well improved specific surface area and the newly formed Ce-O-Fe structure dramatically contributed to the improvement of the redox property of FeCe_0.2TiO_x catalyst, which was well confirmed by H₂-temperature-programmed reduction (H₂-TPR) and in situ XAFS experiments. Such enhanced redox capability could benefit the activation of NO and NH₃ at low temperatures for NO_x removal. The detailed reaction mechanism study further suggested that the facile oxidative dehydrogenation of NH₃ to highly reactive-NH₂ played a key role in enhancing the low-temperature NH₃-SCR performance of FeCe_0.2TiO_x catalyst.     

Effect of silica additive on the thermal stability of catalysts for NOx abatement

The aim of the plesent investigation was to study the effect of SiO₂ addition on the thermal deactivation of V₂O₅/WO₃/TiO₂ catalysts used for NOx pollution abatement. The results suggest that the degradation of the catalytic properties is strongly correlated to the structural ageing which is, in turn, mainly related to the anatase–rutile phase transformation and to the WO₃ phase segregation. The addition of SiO₂ strongly influences the temperature at which these phenomena occur. In fact, it was found that the introduction of this oxide stabilizes the material, retarding the collapse of surface area, and increases the temperature of the anatase to rutile phase transition.     

A Cu-modified active carbon fiber significantly promoted H2S and PH3 simultaneous removal at a low reaction temperature

• Cu_0.15-ACF performs the best for H₂S and PH₃ simultaneous removal. • 550°C and 90°C are separately calcination and reaction temperatures. • The reason why Cu_0.15/ACF shows better performance was found. • The accumulation of H₂PO₄⁻ and SO₄²⁻(H₂O)₆ is the deactivation cause of Cu_0.15/ACF. Poisonous gases, such as H₂S and PH₃, produced by industrial production harm humans and damage the environment. In this study, H₂S and PH₃ were simultaneously removed at low temperature by modified activated carbon fiber (ACF) catalysts. We have considered the active metal type, content, precursor, calcination, and reaction temperature. Experimental results exhibited that ACF could best perform by loading 15% Cu from nitrate. The optimized calcination temperature and reaction temperature separately were 550°C and 90°C. Under these conditions, the most removal capacity could reach 69.7 mg/g and 132.1 mg/g, respectively. Characterization results showed that moderate calcination temperature (550°C) is suitable for the formation of the copper element on the surface of ACF, lower or higher temperature will generate more cuprous oxide. Although both can exhibit catalytic activity, the role of the copper element is significantly greater. Due to the exceptional dispersibility of copper (oxide), the ACF can still maintain the advantages of larger specific surface area and pore volume after loading copper, which is the main reason for better performance of related catalysts. Finally, increasing the copper loading amount can significantly increase the crystallinity and particle size of copper (oxide) on the ACF, thereby improving its catalytic performance. In situ IR found that the reason for the deactivation of the catalyst should be the accumulation of generated H₂PO₄⁻ and SO₄²⁻(H₂O)₆ which could poison the catalyst.     

以TiO2为载体的锰铈系低温SCR脱硝催化剂抗硫抗水性能研究进展

开发具有低温、高活性、高抗硫抗水性的NH₃-SCR脱硝催化剂成为目前广大学者的主要研究方向。锰铈催化剂因为其优异的低温活性而具有广阔的应用前景,但反应气氛中的SO₂和H₂O会使催化剂中毒。本文分析了以TiO₂为载体的锰铈基催化剂在低温氨选择性催化还原过程中SO₂和H₂O的中毒机理,重点从添加助剂和改变催化剂形貌两方面介绍了提高锰铈催化剂抗硫抗水性的研究进展。最后针对目前锰铈催化剂存在的问题对其研究方向进行了展望。     

Chemical poison and regeneration of SCR catalysts for NOx removal from stationary sources

Selective catalytic reduction (SCR) of NO_x with NH₃ is an effective technique to remove NO_x from stationary sources, such as coal-fired power plant and industrial boilers. Some of elements in the fly ash deactivate the catalyst due to strong chemisorptions on the active sites. The poisons may act by simply blocking active sites or alter the adsorption behaviors of reactants and products by an electronic interaction. This review is mainly focused on the chemical poisoning on V₂O₅-based catalysts, environmental-benign catalysts and low temperature catalysts. Several common poisons including alkali/alkaline earth metals, SO₂ and heavy metals etc. are referred and their poisoning mechanisms on catalysts are discussed. The regeneration methods of poisoned catalysts and the development of poison-resistance catalysts are also compared and analyzed. Finally, future research directions in developing poisoning resistance catalysts and facile efficient regeneration methods for SCR catalysts are proposed.     

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst for selective catalytic reduction of NOx

• Activated carbon was proposed to be an efficient accelerant for molded red mud catalyst. • The surface acidity and reducibility were highly improved, as well as the pore structure. • The enrichment of the surface Fe²⁺ and the adsorbed oxygen account for the improvement. Our previous study proved that the acid-pretreatment process could efficiently activate red mud (RM) for the selective catalytic reduction (SCR) of NO_x. However, in terms of the molding process, which is the key step determining whether it can be applied in large-scale industrial, the surface acidity and reducibility of catalyst always decreased dramatically, and part of surface area and pore structure were lost. In this study, we prepared monolithic honeycomb red mud (MHRM) catalysts with activated carbon (AC) as an accelerant and investigated the effect of AC on the MHRM. The results showed that the MHRM with 3 wt.% of AC (MHRM-AC3) exhibited the best SCR performance, and kept more than 80% NO_x conversion in the range of 325°C–400°C. Compared with the MHRM, MHRM-AC1, and HMRM-AC5, the MHRM-AC3 has more mesoporous and macroporous structures, which can provide more adsorption active sites. The AC significantly improved NH₃ adsorption and surface reducibility, which was mainly due to the increase of the surface acid sites (especially the Brönsted acid sites), the concentration of Fe(II), and the surface adsorbed oxygen. The presence of more Fe(II) enriched the surface oxygen vacancies, as well as the surface adsorbed oxygen, due to the charge imbalance and unsaturated chemical bond. And surface adsorbed oxygen exhibited more active than lattice oxygen owing to its higher mobility, which was conducive to NO_x reduction in the SCR reaction.     

Electrocatalytic biofilm reactor for effective and energy-efficient azo dye degradation: the synergistic effect of MnOx/Ti flow-through anode and biofilm on the cathode

● MnO _x /Ti flow-through anode was coupled with the biofilm-attached cathode in ECBR. ● ECBR was able to enhance the azo dye removal and reduce the energy consumption. ● Mn^IV=O generated on the electrified MnO _x /Ti anode catalyzed the azo dye oxidation. ● Aerobic heterotrophic bacteria on the cathode degraded azo dye intermediate products. ● Biodegradation of intermediate products was stimulated under the electric field. Dyeing wastewater treatment remains a challenge. Although effective, the in-series process using electrochemical oxidation as the pre- or post-treatment of biodegradation is long. This study proposes a compact dual-chamber electrocatalytic biofilm reactor (ECBR) to complete azo dye decolorization and mineralization in a single unit via anodic oxidation on a MnO_x/Ti flow-through anode followed by cathodic biodegradation on carbon felts. Compared with the electrocatalytic reactor with a stainless-steel cathode (ECR-SS) and the biofilm reactor (BR), the ECBR increased the chemical oxygen demand (COD) removal efficiency by 24 % and 31 % (600 mg/L Acid Orange 7 as the feed, current of 6 mA), respectively. The COD removal efficiency of the ECBR was even higher than the sum of those of ECR-SS and BR. The ECBR also reduced the energy consumption (3.07 kWh/kg COD) by approximately half compared with ECR-SS. The advantages of the ECBR in azo dye removal were attributed to the synergistic effect of the MnO_x/Ti flow-through anode and cathodic biofilms. Catalyzed by Mn^IV=O generated on the MnO_x/Ti anode under a low applied current, azo dyes were oxidized and decolored. The intermediate products with improved biodegradability were further mineralized by the cathodic aerobic heterotrophic bacteria (non-electrochemically active) under the stimulation of the applied current. Taking advantage of the mutual interactions among the electricity, anode, and bacteria, this study provides a novel and compact process for the effective and energy-efficient treatment of azo dye wastewater.     

全程补碳的A~2/O工艺对同步脱氮除磷的影响

为解决A2/O工艺处理低浓度城市生活污水的碳源问题,采用了甲醇、葡萄糖、乙酸分别作为A2/O系统的碳源,结果表明,甲醇作为系统外加碳源最经济、最合适,其中TN、TP去除率分别达到75.81%和76.21%,NO-x-N被去除时间为30 min.研究最大化利用碳源,得到外加碳源甲醇在厌氧/缺氧/好氧区段的投加比例为1∶2∶0、投加量为400 mg·L-1,硝酸盐回流比为250%时,系统运行效果最佳,TN、NH3-N和TP去除率分别为90.56%、96.67%和92.56%,出水浓度分别为12.3 mg·L-1、4.1 mg·L-1和0.45 mg·L-1,达到GB18918—2002一级A类标准.通过一段时间的运行,在缺氧段发生了反硝化吸磷的现象,有利于碳源的节省和系统的高效运行.     

选择性催化还原(SCR)脱硝催化剂钛钨粉原始粉体的对比

采用XRF、XRD、低温N2吸附曲线、SEM和FT-IR考察了国产和进口钛钨(WO3/TiO2)粉的组成及其微观结构.结果表明,国产和进口钛钨粉中Ti和W的含量相差不大,但是国产钛钨粉都含有少量P,而国外钛钨粉O和S含量较大.国产和进口钛钨粉中TiO2都为锐钛矿型晶型;其表面官能团基本相同;钛钨粉颗粒形貌类似,都为多孔物质,其比表面积相差不大,但是进口样品的孔容高于国产样品.     

Promotional effect of ion-exchanged K on the low-temperature hydrothermal stability of Cu/SAPO-34 and its synergic application with Fe/Beta catalysts

• K⁺ hinder the structural degradation of Cu/SAPO-34 under humid condition<100°C. • K⁺ on Cu/SAPO-34 brings lower acidity and inferior SCR activity at high temperature. • Fe/Beta was used to compensate the low activity of Cu/SAPO-34 at high temperature. • The hybrid catalysts with KCu/SAPO-34 and Fe/Beta show a great potential for using. K ions were introduced onto Cu/SAPO-34 catalysts via the ion-exchange process in order to improve their stability under low-temperature hydrothermal aging. The changes in structure and copper-species contents of these catalysts upon hydrothermal aging were probed in order to investigate their effects on selective catalytic reduction (SCR) activity. For the fresh Cu/SAPO-34 catalysts, K ions had little influence on the chabazite framework but effected their acidities by exchanging with acid sites. After hydrothermal aging, the structural integrity and amount of active sites decreased on pure Cu/SAPO-34. While the K-loaded catalysts showed improved chabazite structure, acidity, and active site conservation with increasing K loading. However, although the 0.7 wt% K catalyst maintained the same crystallinity, active site abundance, and low-temperature SCR activity as the fresh catalyst upon aging, an apparent decrease in SCR activity at high temperature was observed because of the inevitable decrease in the number of Brönsted acid sites. To compensate for the activity disadvantage of K-loaded Cu/SAPO-34 at high temperature, Fe/Beta catalysts were co-employed with K-loaded Cu/SAPO-34, and a wide active temperature window of SCR activity was obtained. Thus, our study reveals that a combined system comprising Fe/Beta and K-loaded Cu/SAPO-34 catalysts shows promise for the elimination of NO_x in real-world applications.     

C2H2 semi-hydrogenation on the PdxMy cluster/graphdiyne catalysts:Effects of cluster composition and size on the activity and selectivity

C₂H₂ semi-hydrogenation has been widely applied in industry to eliminate trace C₂H₂ from C₂H₄ feed.C₂H₂ semi-hydrogenation to C₂H₄ on a series of the newly designed catalysts,graphdiyne (GDY) as a new carbon allotrope supported different sizes of Pd_xM_yclusters (Pd_xM_y/GDY,M=Cu,Ag,Au,Ni;x+y=1-3),were studied using DFT calculations.The results fou...     

Utilizing transparent and conductive SnO2 as electron mediator to enhance the photocatalytic performance of Z-scheme Si-SnO2-TiOx

• A novel Z-scheme Si-SnO₂-TiO_x with SnO₂ as electron mediator is first constructed. • Transparent and conductive SnO₂ can pass light through and promote charge transport. • V_O from SnO₂ and TiO_x improve photoelectrochemical performances. • Efficient photocatalytic degradations originate from the Z scheme construction. Z-scheme photocatalysts, with strong redox ability, have a great potential for pollutants degradation. However, it is challenging to construct efficient Z-scheme photocatalysts because of their poor interfacial charge separation. Herein, by employing transparent and conductive SnO₂ as electron mediator to pass light through and promote interfacial charge transportation, a novel Z-scheme photocatalyst Si-SnO₂-TiO_{x (1<x<2)} was constructed. The Z-scheme photocatalyst displayed an order of magnitude higher photocurrent density and a 4-fold increase in open-circuit potential compared to those of Si. Moreover, the onset potential shifted negatively for approximately 2.2 V. Benefiting from these advantages, this Z-scheme Si-SnO₂-TiO_x exhibited efficient photocatalytic performance toward phenol degradation and mineralization. 75% of the phenol was degraded without bias potential and 70% of the TOC was removed during phenol degradation. Other typical pollutants such as bisphenol A and atrazine could also be degraded without bias potential. Introducing a transparent and conductive electron mediator to construct Z-scheme photocatalyst gives a new sight to the improvement of photocatalytic performance in Z scheme.     

SO2和NO2胁迫对红花荷等植物光合生理影响及抗性评价

为探讨红花荷(Rhodoleia championii)等12种园林植物抗SO2和NO2污染能力,以1～2年生实生苗为材料,通过人工气候室的盆栽实验,研究不同SO2和NO2混合气体胁迫对园林植物苗木光合参数和相对叶绿素含量的影响,并利用隶属函数法及系统聚类分析法对其抗SO2和NO2污染能力进行了综合评价。结果表明,植物叶片净光合速率、气孔导度、蒸腾速率和相对叶绿素含量基本上随着SO2和NO2胁迫的加剧而逐渐降低,但水分利用效率受净光合速率和蒸腾速率变化的影响规律不明显。综合隶属函数和聚类分析可知,红花荷和红千层(Callistemon rigidus)抗污染能力强,杜鹃红山茶(Camellia azalea)和粉红羊蹄甲(Bauhinia blakeana)抗污染能力较强,红花银桦(Grevillea robusta)和无忧树(Saraca divespierre)抗污染能力中等,大叶紫薇(Lagerstroemia speciosa)、金花风铃木(Tabebuia chrysantha)和腊肠树(Cassia fistula)抗污染能力较弱,而本地火焰木(Spathodea nilotica)、复羽叶栾树(Koelreuteria bipinnata)和樱花(Prunus serrulata)抗污染能力弱。研究结果为火电厂、陶瓷厂、钢铁厂、石化厂等重度酸污染地区植物选择提供参考。     

Enhanced catalytic oxidation of 2,4-dichlorophenol via singlet oxygen dominated peroxymonosulfate activation on CoOOH@Bi2O3 composite

• Bi₂O₃ cannot directly activate PMS. • Bi₂O₃ loading increased the specific surface area and conductivity of CoOOH. • Larger specific surface area provided more active sites for PMS activation. • Faster electron transfer rate promoted the generation of reactive oxygen species. • ¹O₂ was identified as dominant ROS in the CoOOH@Bi₂O₃/PMS system. Cobalt oxyhydroxide (CoOOH) has been turned out to be a high-efficiency catalyst for peroxymonosulfate (PMS) activation. In this study, CoOOH was loaded on bismuth oxide (Bi₂O₃) using a facile chemical precipitation process to improve its catalytic activity and stability. The result showed that the catalytic performance on the 2,4-dichlorophenol (2,4-DCP) degradation was significantly enhanced with only 11 wt% Bi₂O₃ loading. The degradation rate in the CoOOH@Bi₂O₃/PMS system (0.2011 min⁻¹) was nearly 6.0 times higher than that in the CoOOH/PMS system (0.0337 min⁻¹). Furthermore, CoOOH@Bi₂O₃ displayed better stability with less Co ions leaching (16.4% lower than CoOOH) in the PMS system. These phenomena were attributed to the Bi₂O₃ loading which significantly increased the conductivity and specific surface area of the CoOOH@Bi₂O₃ composite. Faster electron transfer facilitated the redox reaction of Co (III) / Co (II) and thus was more favorable for reactive oxygen species (ROS) generation. Meanwhile, larger specific surface area furnished more active sites for PMS activation. More importantly, there were both non-radical (¹O₂) and radicals (SO₄⁻•, O₂⁻•, and OH•) in the CoOOH@Bi₂O₃/PMS system and ¹O₂ was the dominant one. In general, this study provided a simple and practical strategy to enhance the catalytic activity and stability of cobalt oxyhydroxide in the PMS system.     

δ15N-stable isotope analysis of NHx: An overview on analytical measurements,source sampling and its source apportionment

• Challenges in sampling of NH₃ sources for d¹⁵N analysis are highlighted. • Uncertainties in the isotope-based source apportionment of NH₃ and NH₄⁺ are outlined. • Characterizing dynamic isotopic fractionation may reduce uncertainties of NH_x science. Agricultural sources and non-agricultural emissions contribute to gaseous ammonia (NH₃) that plays a vital role in severe haze formation. Qualitative and quantitative contributions of these sources to ambient PM_2.5 (particulate matter with an aerodynamic equivalent diameter below 2.5 µm) concentrations remains uncertain. Stable nitrogen isotopic composition (δ¹⁵N) of NH₃ and NH₄⁺ (δ¹⁵N(NH₃) and δ¹⁵N(NH₄⁺), respectively) can yield valuable information about its sources and associated processes. This review provides an overview of the recent progress in analytical techniques for δ¹⁵N(NH₃) and δ¹⁵N(NH₄⁺) measurement, sampling of atmospheric NH₃ and NH₄⁺ in the ambient air and their sources signature (e.g., agricultural vs. fossil fuel), and isotope-based source apportionment of NH₃ in urban atmosphere. This study highlights that collecting sample that are fully representative of emission sources remains a challenge in fingerprinting δ¹⁵N(NH₃) values of NH₃ emission sources. Furthermore, isotopic fractionation during NH₃ gas-to-particle conversion under varying ambient field conditions (e.g., relative humidity, particle pH, temperature) remains unclear, which indicates more field and laboratory studies to validate theoretically predicted isotopic fractionation are required. Thus, this study concludes that lack of refined δ¹⁵N(NH₃) fingerprints and full understanding of isotopic fractionation during aerosol formation in a laboratory and field conditions is a limitation for isotope-based source apportionment of NH₃. More experimental work (in chamber studies) and theoretical estimations in combinations of field verification are necessary in characterizing isotopic fractionation under various environmental and atmospheric neutralization conditions, which would help to better interpret isotopic data and our understanding on NH_x (NH₃ + NH₄⁺) dynamics in the atmosphere.     

纳米二氧化硅对两性生殖和孤雌生殖卤虫无节幼体毒性影响的比较研究

研究了纳米二氧化硅(Nano-SiO_2)悬浮液对美国大盐湖两性生殖型卤虫(Artemia francisana,GSL)和渤海湾孤雌生殖型卤虫(Artemia parthenogenetica,BH)无节幼体的急性毒性和抗氧化酶系统的影响。研究结果表明,Nano-SiO_2对GSL和BH无节幼体24 h-LC50分别为23.02 mg·m L~(-1)和20.96 mg·m L~(-1),属低级毒性。Nano-SiO_2降低了GSL和BH无节幼体还原型谷胱甘肽(GSH)含量,抑制了过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性,致丙二醛(MDA)含量升高,表明氧化应激反应是导致Nano-SiO_2对卤虫无节幼体致死的作用机制之一。     

过氧化氢和一氧化氮在小球藻抗阿特拉津胁迫中的作用

过氧化氢(H_2O_2)和一氧化氮(NO)作为信号分子,可调节植物生长、发育以及应对外源性胁迫。利用过氧化氢酶(CAT)以及NO清除剂(PTIO),研究了除草剂阿特拉津(atrazine,100μg·L~(-1))影响小球藻生长的机理,并分析内源性H_2O_2和NO在小球藻抗除草剂胁迫中的作用。研究结果表明,阿特拉津在诱发小球藻细胞死亡的过程中,不同程度促发了H_2O_2和NO生成;外源CAT可通过清除H_2O_2和诱导NO来缓解阿特拉津对小球藻的生长抑制;PTIO与阿特拉津的联合实验进一步证实,小球藻体内的NO诱导与H_2O_2的爆发无关,它们之间的合成没有相关性。因此,除草剂阿特拉津主要通过诱导小球藻体内的H_2O_2爆发来破坏藻细胞,抑制其生长,与NO的信号传递无关。