Emission Of Pb Research Articles

Sensitivity improvement of laser-induced breakdown spectroscopy to detect heavy metals in water by Tesla coil discharge

Tesla coil discharge combined with LIBS was used to enhance the emission of Cr(i) and Pb(i), and improve the detection sensitivity of heavy metals in water.

Capture effect of K and Pb by kaolin during co-firing of coal and wheat straw: Experimental and theoretical methods

To reduce the emission of Pb in coal combustion and K in biomass combustion respectively, kaolin was applied widely as the in-furnace sorbent. In this study, effect of kaolin on K and Pb simultaneously in co-firing of coal and wheat straw (WS) was investigated in a lab-scale bubble fluidized bed. Relative distribution of the two elements was respectively compared with the conditions of the individual fuel combustion. Mechanism of reactions among coal, WS and kaolin was investigated via sample analysis and theory calculation. Experimental results indicated that kaolin could exert negative effect on the release of the two elements by transferring them into fly ash and bottom solid and the effect was promoted with the increasing temperature. During co-firing, sulfation reaction of K was superior to the capture reaction of K by kaolin at low temperatures while adsorption of K was slightly enhanced compared with the theory value based on results of the two individual fuels. Oppositely, the capture effect of Pb in co-firing was impaired to some extent. Lastly, result of DFT (Density Functional Theory) calculation proved that existence of KCl inhibited the adsorption of PbCl2 on metakaolin by occupying the optimum adsorption site and reducing the adsorption energy at high temperatures.

Migration and transformation of trace elements during sewage sludge and coal slime Co-combustion

Co-combustion of sewage sludge (SS) and coal slime (CS) could improve the combustion properties of the two materials, however, high levels of trace elements (TEs) can be released from the two wastes, resulting in secondary pollution. The migration and transformation behavior of As, Cr, Pb, Zn, and Mn during co-combustion is explored in current research. The results showed co-combustion could inhibit the emission of Zn, As, Pb, and Mn, and the effect was more pronounced for Zn, As and Mn. Meanwhile, minerals like kaolinite and gypsum were found to generated in the ash from co-combustion but not solo-combustion. Model experiments demonstrated that kaolinite captured As, Pb and Mn, while gypsum captured Zn, As and Mn but facilitated the emission of Pb and Cr. This well explained the distinct TEs emission characteristics between co-combustion and solo combustion. As the temperature elevated, kaolinite in co-combustion ash decomposed and the generation of gypsum was promoted. In this way, the emission ratios of Zn, As, and Mn initially increased but subsequently decreased between 700 and 1300 °C, whereas Pb and Cr emission ratios increased by twofold within the same temperature range. Leaching characteristics and risk assessment code on co-combustion ashes were also conducted in this study. The results indicated a marginal elevation in the risk associated with trace elements (TEs) following co-combustion, provided that all five TEs remained within the limits of national standards.

Isotopic Signatures and Outputs of Lead from Coal Fly Ash Disposal in China, India, and the United States.

Despite extensive research and technology to reduce the atmospheric emission of Pb from burning coal for power generation, minimal attention has been paid to Pb associated with coal ash disposal in the environment. This study investigates the isotopic signatures and output rates of Pb in fly ash disposal in China, India, and the United States. Pairwise comparison between feed coal and fly ash samples collected from coal-fired power plants from each country shows that the Pb isotope composition of fly ash largely resembles that of feed coal, and its isotopic distinction allows for tracing the release of Pb from coal fly ash into the environment. Between 2000 and 2020, approx. 236, 56, and 46 Gg Pb from fly ash have been disposed in China, India, and the U.S., respectively, posing a significant environmental burden. A Bayesian Pb isotope mixing model shows that during the past 40 to 70 years, coal fly ash has contributed significantly higher Pb (∼26%) than leaded gasoline (∼7%) to Pb accumulation in the sediments of five freshwater lakes in North Carolina, U.S.A. This implies that the release of disposed coal fly ash Pb at local and regional scales can outweigh that of other anthropogenic Pb sources.

Pb-Doped Ag2 Se Quantum Dots with Enhanced Photoluminescence in the NIR-II Window.

Ag2 Se quantum dots (QDs) as an effective biological probe in the second near-infrared window (NIR-II, 1000-1700nm) have been widely applied in bioimaging with high tissue penetration depth and high spatiotemporal resolution. However, the ions deficiency and crystal defects caused by the high Ag+ mobility in Ag2 Se crystals are mainly responsible for the inefficient photoluminescence (PL) of Ag2 Se QDs. Herein, a tailored route is reported to achieve controllable doping of Ag2 Se QDs in which Ag is exchanged by Pb via cation exchange (CE), which is unattainable by direct synthetic methods. The Pb-doped Ag2 Se QDs (denoted as Pb:Ag2 Se QDs) present fire-new optical features with significantly enhanced PL intensity of 4.2 folds. Photoelectron spectroscopy confirms that Pb acts as an n-type dopant for Ag2 Se QDs and therefore the electronic impurities provide additional carriers to fill the traps. Moreover, the general validity of this method is demonstrated to convert different sized Ag2 Se into Pb:Ag2 Se QDs, so that a wide range of NIR-II PL with high intensity is obtained. The bright NIR-II emission of Pb:Ag2 Se QDs is further successfully performed in lymphatic system mapping.

Insight into the origin of carbon matrix effects on the emission signal of atomic lines in inductively coupled plasma optical emission spectrometry

In inductively coupled plasma optical emission spectrometry (ICP-OES), the presence of carbon in the matrix strongly affects (positively and negatively) the emission signal of atomic lines. However, the emission signal of ionic lines is mostly unaffected by this concomitant. The goal of this work is to gain insight into the origin of carbon matrix effects on the signal of atomic lines in ICP-OES. To this end, the emission signal of a total of 3608 lines (i.e., 1755 atomic and 1853 ionic lines) of 62 elements (Ag, Al, As, Au, B, Ba, Be, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hg, Ho, I, In, Ir, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Re, Rh, S, Sb, Sc, Se, Sm, Sn, Sr, Tb, Te, Th, Ti, Tm, U, V, Y, Yb, Zn and Zr) were registered for carbon containing solutions (20 g L−1) prepared from glycerol. Results were compared to those obtained operating a 1% w w−1 HNO3 solution. Compared to the HNO3 reference solution, emission signals for As, B, Hg, I, P, Se and Te atomic lines were increased for the carbon containing solution. However, signal suppression was noticed for the signal emission of Ag, Al, Ba, Be, Ca, Cd, Co, Cr, Cs, Eu, Fe, Ga, Ge, K, Ho, In, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Ni, Pb, Pd, Pr, Pt, Re, Rh, S, Sb, Sc, Sn, Sr, Ti, Tm, V, Y and Zr atomic lines. No measurable matrix effects within experimental uncertainties were registered for Au, Cu, Ir, Gd and Zn atomic lines. As regards Ce, Dy, Er, Nd, Sm, Tb, Th, U and Yb no clear conclusion about matrix effects was feasible due to the limited atomic emission wavelengths monitored. Experimental results showed that the intensity of matrix effects depends on both analyte ionization energy and the energy of the electronic upper level involved in the electronic transition. Matrix effects on atomic emission lines can be explained by the simultaneous occurrence of different mechanisms: (i) charge transfer reactions; (ii) collisional ionization; and (iii) collisional excitation with carbon-based species. Because these mechanisms mostly affect analyte atomic population, carbon matrix effects are more significant on the emission signal of atomic lines rather than ionic ones. Finally, the judicious analyte wavelength selection is critical to minimize carbon matrix effects for those elements for which the most sensitive wavelength is atomic (i.e., Se and alkali elements). On this regard, the selection of the internal standard should consider both the ionization energy and the energy of the electronic upper level of the analyte.

Insights into leaded gasoline registered in mud depocenters derived from multivariate statistical tool: southeastern Brazilian coast.

Lead has been widely used since antiquity, but its uses drastically increased during the Industrial Revolution. The global emission of Pb into the environment was mainly due to tetraethyl lead added to gasoline as an antiknock additive. Because of its toxicity and neurological effects, the compound was phased out in the 1980s. Isotopic signatures are widely applied to differentiate sources of Pb; however, this is an expensive and sophisticated analysis compared to elemental analysis. Thus, this study aims to gain insight into leaded gasoline registered in mud depocenters from the southeastern Brazilian coast using multivariate statistical tools on elemental analysis data of trace elements. Seven multiple cores were collected on board the Research Vessel Alpha Crucis. Al, As, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, Sc, Sr, V and Zn were analyzed by acid digestion and quantified by ICP-OES. Levels and enrichment factors of Pb resulted in homogeneous columns, indicating that small variations in concentrations can be attributed to grain size differences, not presenting contaminated levels. From statistical results, the highest contribution on the first component was represented by a lithogenic source with the leaching of continental rocks. Lead content was notable in its high loadings in other components, which suggests atmospheric deposition. An increase in these components in subsurface samples from vertical profiles between 1935 and 1996 could represent a fingerprint of the consumption of leaded gasoline in Brazil between 1923 and 1989. Thus, statistical analysis of elemental data enabled to infer possible sources and pathways of Pb to the environment, without isotopic analysis.

Characteristics of heavy metal concentrations and risk assessment for giant pandas and their habitat in the Qinling Mountains, China.

High concentrations of heavy metals in the environment threaten the quality of ecosystems and the health of human beings and animals. Giant panda (Ailuropoda melanoleuca), which is endemic to China and a global conservation icon, has the largest density in the Qinling Mountains. This paper investigated the spatiotemporal variation of heavy metal concentrations in soil (N = 44) at the regional scale with three zones of urban areas, mountain edges, and central mountains, the temporal variation of heavy metal concentrations in three bamboo species (N = 19) and two types of feces (N = 10), and assessed the ecological risk and health risk for giant pandas and their habitat in the Qinling Mountains. The results showed that the median concentrations of studiedeight heavy metals mercury (Hg), arsenic (As), copper (Cu), manganese (Mn), zinc (Zn), chromium (Cr), lead (Pb), and cadmium (Cd) in soil exceeded the background values of Shaanxi Province except Pb. The median concentrations of Hg, Zn, Cr, Pb, and Cd in bamboo surpassed the reference standard (RS) of national food safety limits in vegetables for human intake, but the concentration of Zn was within the nutrient range in the bamboo plants. Heavy metals were enriched more in feces of captive than the wild giant pandas, which illustrated either higher ingestion or lower digestibility for captive giant panda. Ecological risk assessment of soil by the geo-accumulation index (Igeo) and risk index (RI) showed strong pollution by Hg and moderate pollution by Cd. Health risk assessment by the hazard index (HI) showed a potential to strong risk for giant pandas exposed to Pb, As, and Hg. In addition, the concentrations of heavy metals in feces showed a higher exposure risk for captive giant pandas than wild giant pandas. We suggest that attention should be paid to and all effective measurements should be taken for reducing the emission of Hg, As, Pb, and Cd in the study area.

Effect of modified fly ash injection on As, Se, and Pb emissions in coal-fired power plant

Modified fly ash injection was installed at the outlet of selective catalytic reduction (SCR) systems in a 1000 MW coal-fired power plant, reaching 94% mercury capture rate. Due to chemical and mechanical treatment of raw fly ash, the modified fly ash has a higher oxidation capability, finer particle size, and more active sites. The co-benefit of the reduction of trace elements (TEs), such as arsenic (As), selenium (Se), and lead (Pb), when using on-line modified fly ash was investigated in this study. The results between with and without modified fly ash indicated that it is between 30% and 74% of reduction on the three TEs’ emission in both electrostatic precipitator (ESP) and wet flue gas desulfurization (WFGD) systems with the additional fly ash injection. The finer particle property is the dominant factor to reduce the emission of Se and Pb at such lower temperature (Temp) range. The Se itself also has the higher volatility to make capture more difficult than that of Pb. The strong chemical reaction between As and calcium with the smaller particle size reduced the As in the gas phase. The materials balance including solid, liquid, and gas phase also establish to confirm the sampling and measurement are validated of each value in this study. Above 97% of As and Pb are in the fly ash. Around 67% of the Se was captured in the WFGD unit. The Se had the higher emission in the stack.

Ultraviolet upconversion emission of Pb2+ ions sensitized by Yb3+-trimers in CaF2

Under 978 nm near infrared (NIR) excitation, ultraviolet (UV) upconversion (UC) emissions from Pb2+ ions in CaF2:Pb2+,Yb3+ were first observed at room temperature.

Tracing source and migration of Pb during waste incineration using stable Pb isotopes

Emission of Pb is a significant environmental concern during solid waste incineration. To target Pb emission control strategies effectively, the major sources of Pb in the waste incineration byproducts must be traced and quantified. However, identifying the migration of Pb in each waste component is difficult because of the heterogeneity of the waste. This study used a laboratory-scale incinerator to simulate the incineration of municipal solid waste (MSW). The Pb isotope ratios of the major waste components (207Pb/206Pb=0.8550–0.8627 and 208Pb/206Pb=2.0957–2.1131) and their incineration byproducts were measured to trace sources and quantify the Pb contribution of each component to incineration byproducts. As the proportions of food waste (FW), newspaper (NP), and polyethylene bag (PE) in the artificial MSW changed, the contribution ratios of FW and PE to Pb in fly ash changed accordingly, ranging from 31.2% to 50.6% and from 35.0% to 41.8%, respectively. The replacement of PE by PVC significantly increased the partitioning and migration ratio of Pb. The use of Pb isotope ratios as a quantitative tool for tracing Pb from raw waste to incineration byproducts is a feasible means for improving Pb pollution control.

Spatio-temporal distribution and sources of Pb identified by stable isotopic ratios in sediments from the Yangtze River Estuary and adjacent areas.

To understand the spatio-temporal distribution and sources of Pb in the sediments of the Yangtze River Estuary and its adjacent areas, 25 surface sediments and 1 sediment core were collected from the study areas. The concentrations of Al and Pb of these sediments exhibit a decreasing trend from the nearshore towards the offshore, with higher concentrations in the coastal areas of the East China Sea (ECS) and southwest of Jeju Island. According to the stable isotopic ratios of Pb, in combination with the elemental ratios and clay mineral data, it is inferred that sedimentary Pb in the surface sediments of the coastal areas of the ECS may come primarily from the Yangtze River, while the Pb southwest of Jeju Island is probably derived from both the Yangtze and Yellow Rivers. The particulate Pb derived from the Yangtze River was possibly dispersed along two paths: the path southward along the coastline of the ECS and the path eastward associated with the Changjiang Diluted Water (CDW), which crosses the shelf of the ECS towards the area southeast of Jeju Island. Although the Yangtze River Basin witnessed rapid economic development during the period from the late 1970s to the middle 1990s, the influence of human activity on Pb concentration remained weak in the Yangtze River Estuary. Since the early 2000s, however, sedimentary Pb has been significantly increasing in the coastal mud areas of the ECS due to the increasing influence of human activity, such as the increase in atmospheric emission of anthropogenic Pb in China, construction of the Three Gorges Dam (TGD), and the construction of smaller dams in the upper reaches of the Yangtze River. Coal combustion and the smelting of non-ferrous metals are possible anthropogenic sources for the sedimentary Pb in the Yangtze River Estuary.

The content of heavy metals in the leaves of Tilia cordata Mill. and in the soils of urban ecosystems of Cherkasy city

The growth of technogenic impact on urbo-landscapes is accompanied by man-made contamination of the environment. Among the most toxic and widespread pollutants of the urban ecosystems an important place belongs to heavy metals. The soil is the main source of accumulation of heavy metals and its uptake by the biota objects, including plants. Elevated concentrations of heavy metals in plant products, in turn, lead to intoxication of people and animals. Toxicity of heavy metals due to their biological activity and availability, resistance of their compounds in the environment, the possibility of small concentrations cause significant negative effects. For the city of Cherkasy the main polluters of the environment with heavy metals are the subsidiary of Cherkasy thermal power (accounting for 75% of the total amount of heavy metals emitted, and contribution of thermal power for emission of Pb, Cu and Zn reach 85%) and automobile transport. It should be noted that the city of Cherkasy (population 285.000 people) is an important economic center of Ukraine, with well-developed chemical and automobile industries. With atomic absorption spectroscopy the content of heavy metals (Cu, Zn, Pb and Cd) in the leaves of bio-indicator species Tilia cordata Mill. and soils from 24 localities of the city of Cherkassy was examined. The general content of the leaf biomass and soils from different localities of the degree of technogenic pollution of heavy metals are arranged in a sequence Zn > Cu > Pb > Cd. In the city the content Pb and Cd in soils were below the MPK (maximum permissible concentration). Apparently, the content of copper and zinc soils, first of all, caused by pollution of chemical plants emissions, lead, due to industrial and transport factors and cadmium, of the distances to highways. The data obtained suggest that small-leaved linden (T. cordata Mill.) is as a representative species for bio-indication of heavy metals pollution in urban territories

Impact of CaO and CaCO3 addition on agglomeration/defluidization and heavy metal emission during waste combustion in fluidized-bed

In this study, CaO and CaCO3 were used as additives to investigate the inhibition of agglomeration/defluidization and adsorption of Pb and Cd. The results showed that defluidization time may be prolonged when CaO or CaCO3 is added to the artificial waste. Before defluidization, Pb and Cd emissions were not intensified significantly in the existence of Na; however, after defluidization, the emission of Pb and Cd increased significantly. The heavy metal emission concentration was lower when CaO or CaCO3 was added to the artificial waste than when only Na was added. CaCO3 showed a stronger defluidization inhibition effect because of the longer defluidization time. For different parameters, the heavy metal emission concentration appeared to decrease with an increase in the operating temperature; however a change in the gas velocity did not affect the heavy metal emission. In addition, an increase in the bed material size considerably reduces the defluidization time. A small bed material size is more favored as the large specific surface area in this case allows for the adsorption of a greater amount of heavy metal and more efficient mixing with waste.

Significant sensitivity improvement of alternating current driven-liquid discharge by using formic acid medium for optical determination of elements

A method has been developed to improve the performance of alternating-current electrolyte atmospheric liquid discharge (ac-EALD) optical emission spectrometry for the determination of elements. Significant enhancement of emission intensity was achieved by adding organic substance into the nitric acid electrolyte solutions. Under the optimized conditions, 3% (v/v) formic acid in nitric acid (pH 1.0) produced 13 times enhancement for Ag and 7% (v/v) formic acid resulted in 17 times enhancement for Cd. The emission of Pb was even enhanced 78 times in the presence of 3% formic acid. In addition, the signal stability was also improved compared with that in the absence of organic substances. Repeatability was 0.8% for 0.1mgL−1 Ag, 0.7% for 0.2mgL−1 Cd and 2.6% for 1mgL−1 Pb standard solutions (n=5). The limits of detection of Ag, Cd and Pb were 1, 17 and 45μgL−1, respectively. The accuracy of the method was demonstrated by determination of elements in simulated natural water samples (GBW(E)080402 and GBW(E)080399).

High-uranium matrix effect in zircon and its implications for SHRIMP U–Pb age determinations

A correlation has previously been noted between extremely high-uranium concentrations in zircon and apparent U/Pb age as measured in ion microprobe analysis. Here we present data from two zircon populations with extremely high-uranium concentrations in an attempt to quantify effects related to the nature of the samples and/or instrumentally induced fractionation (instrument, analytical setup, and/or matrix effect). The high-uranium matrix effect is apparent in zircons from the 180Ma Tasmanian Dolerite, which typically shows an increase in Pb/U age of around 3% per thousand μg/g of uranium when measured on SHRIMP RG. One session on SHRIMP RG shows a correlation with 8% per thousand μg/g of uranium. Data from SHRIMP II show a weak correlation and no correlation is evident in data collected on SHRIMP I. High-uranium zircons from the 98Ma Mt Dromedary monzonite show little to no correlation between uranium concentration and U/Pb age. Analyses of younger (~20–50Ma) high-uranium zircons show a correlation between uranium concentration and an increase in apparent age, but this is less pronounced than the results obtained from the older Tasmanian Dolerite. Raman spectroscopy of the Tasmanian Dolerite zircons shows that these zircons are metamict. The link between uranium concentration and apparent age appears to be related to the degradation of the zircon matrix from radiation damage. The change in matrix enhances the emission of Pb+ relative to U and U oxide species. As this effect is associated with matrix and machine parameters, an external correction cannot be made assuming a constant correction value. With a secondary high-uranium standard, it might be possible to quantify the effect, but the matrix of this standard needs to be closely matched in age (radiation damage) and chemistry (U concentration); this solution is impractical. We instead propose that workers be aware of this matrix effect in SHRIMP analyses of zircon and to use Raman spectroscopy before or after SHRIMP analyses to ensure that the zircon is crystalline. These findings have important consequences for the use of SHRIMP data for zircon geochronology.

Characteristics of liquid electrode plasma for atomic emission spectrometry

Liquid electrode plasma atomic emission spectrometry (LEP-AES) is a recently developed elemental analysis method that uses microplasma. LEP forms in a vapor bubble generated inside a narrow-center microchannel by using high-voltage DC pulse power. We studied the characteristics of LEP and atomic emission of lead (Pb), as an example element, which has not been described in detail. We estimated the plasma parameters and observed the expansion and shrinkage of a vapor bubble with discharge as well as the time course and spatial distribution of the atomic emission of Pb (405.78 nm). The applied voltage was 2.5 kV and the pulse width was less than 3 ms, which produced a current of about 100 mA. We found that the excitation temperature was about 8000 K and the electron density was about 1 × 1015 cm−3. We also found that two quite different emission phases occurred separately during the time course. The first emission phase corresponds to the first expansion and shrinking of the bubble around atmospheric pressure and the second emission phase corresponds to the re-expansion of the bubble and emission at reduced pressure with higher atomic and lower background emissions. Maximum atomic and background emissions were observed at the narrowed center of the microchannel, but there was an additional local maximum atomic emission region at the anode side bubble–liquid interface where the background emission was very low, which would be a better condition for sensitive measurement. The limit of detection determined in our experiment was 4.0 μg L−1 for Pb.

Simultaneous multielement detection in particle beam/hollow cathode-optical emission spectroscopy

Presented here is the development of a particle beam/hollow cathode-optical emission spectroscopy source that has been interfaced with a high resolution polychromator for use as a species-specific detector for chromatographic separations. Use of the high resolution JY RF-5000 polychromator allows simultaneous, multielement analysis; a necessary requirement for comprehensive speciation analysis. Parametric optimization was performed for the nebulization conditions, desolvation temperature, glow discharge current and pressure, and the source block temperature (vaporization) using nitrate salts containing lead, nickel, and silver. Peak area, height, and width were recorded for optical emission of Pb (I) 220.35 nm, Ni (I) 341.41 nm, and Ag (I) 338.28 nm in order to determine optimal peak characteristics under chromatographic separation conditions. Response curves for a multielement salt solution containing Pb, Ni, and Ag were obtained using the optimized conditions, with detection limits for triplicate injections of 2.2, 0.17, and 0.19 ng, respectively. The ability to monitor multiple elements simultaneously reveals the existence of interelement matrix effects that have not been noted previously in hollow cathode devices. The ability to monitor metals and non-metals is demonstrated towards the future application of this system as a tool for metallomic studies.

Atomic emission spectrographic determination of trace elements in environmental objects using a two-jet argon arc plasmatron

The effect of the main components (K, Na, Ca, Mg, Fe) on the atomic and ionic emission of trace elements Sr, Lu, V, Sc, Ti, Cr, Pb, Sn, Ni, Co, Bi, Mn, Pd, Zn, Be, Ba, Zr, Y, and La in atomic emission spectrometry with a two-jet argon arc plasmatron was studied to improve the accuracy of the quantitative multielement analysis of natural objects. It was shown that all of the studied macro elements to a certain extent enhance the analytical signal. The maximum enhancement was 2.5-fold. The effect of the matrix composition of the material is not strong and can easily be controlled by properly selecting the operational conditions of the formation of a plasma jet and bufferation, and also samples and reference elements. It was shown that a wide spectrum of trace elements can be quantitatively determined in various rocks, soils, and plant ashes with a relative standard deviation of 6–15% and detection limit of n × 10−4 to n × 10−6% using unified reference samples prepared synthetically.

Strong electron emission of antiferroelectric ceramic

The electron emission of a novel antiferroelectric cathode material La-doped Pb(Zr，Sn，Ti)O3(PLZST)has been studied. For driving voltage of 800V and accelerating voltage of 0V，the emission current density was 1.27A/cm2. For driving voltage of 800V and accelerating voltage of 4kV，a strong emission current density with 1700A/cm2 was obtained. The dependence of emission current on accelerating voltage was analyzed and the mechanism of antiferroelectric electron emission was discussed. It was found that strong electron emission from antiferroelectric material can be realized under lower driving voltage and the emission current was much larger than that predicted by the Child-Langmuir law. Local antiferroelectric-ferroelectric phase transition in the vicinity of the triple junction leads to initial electron emission，and these initial electrons then cause desorption of gas which had been absorbed at the ceramic surface.The desorbed gas is then ionized，which leads to plasma generation. The formation of surface plasma enhances the emission current.