Enhancing electromagnetic wave absorption with core‐shell structured SiO_(2)@MXene@MoS_(2) nanospheres

Material composition and structural design are important factors influencing the electromagnetic wave(EMW)absorption performance of materials.To alleviate the impedance mismatch attributed to the high dielectric constant of Ti_(3)C_(2)T_(x)MXene,we have successfully synthesized core‐shell structured SiO_(2)@MXene@MoS_(2)nanospheres.This architecture,comprising SiO_(2) as the core,MXene as the intermediate layer,and MoS_(2) as the outer shell,is achieved through an electrostatic self‐assembly method combined with a hydrothermal process.This complex core‐shell structure not only provides a variety of loss mechanisms that effectively dissipate electromagnetic energy but also prevents self‐aggregation of MXene and MoS_(2) nanosheets.Notably,the synergistic combination of SiO_(2) and MoS_(2) with highly conductive MXene enables the suitable dielectric constant of the composites,ensuring optimal impedance matching.Therefore,the core‐shell structured SiO_(2)@MXene@MoS_(2) nanospheres exhibit excellent EMW absorption performance,featuring a remarkable minimum reflection loss(RL_(min))of−52.11 dB(2.4 mm).It is noteworthy that these nanospheres achieve an ultra‐wide effective absorption bandwidth(EAB)of 6.72 GHz.This work provides a novel approach for designing and synthesizing high‐performance EMW absorbers characterized by“wide bandwidth and strong reflection loss.”

Highly enhanced UV absorption and light emission of monolayer WS_(2)through hybridization with Ti_(2)N MXene quantum dots and g-C_(3)N_(4)quantum dots

Two-dimensional(2D)transition metal dichalcogenides(TMD)are atomically thin semiconductors with promising optoelectronic applications across the visible spectrum.However,their intrinsically weak light absorption and the low photoluminescence quantum yield(PLQY)restrict their performance and potential use,especially in ultraviolet(UV)wavelength light ranges.Quantum dots(QD)derived from 2D materials(2D/QD)provide efficient light absorption and emission of which energy can be tuned for desirable light wavelength.In this study,we greatly enhanced the photon absorption and PLQY of monolayer(1L)tungsten disulfide(WS_(2))in the UV range via hybridization with 2D/QD,particularly titanium nitride MXene QD(Ti_(2)N MQD)and graphitic carbon nitride QD(GCNQD).With the hybridization of MQD or GCNQD,1LWS_(2)showed a maximum PL enhancement by 15 times with 300 nm wavelength excitation,while no noticeable enhancement was observed when the excitation photon energy was less than the bandgap of the QD,indicating that UV absorption by the QD played a crucial role in enhancing the light emission of 1L-WS_(2)in our 0D/2D hybrid system.Our findings present a convenient method for enhancing the photo-response of 1L-WS_(2)to UV light and offer exciting possibilities for harvesting UV energy using 1L-TMD.

Synthesis and microwave absorption performance of heat-treated RF/SiO_(2)aerogels

The well-designed composite with satisfactory electromagnetic microwave absorption at high temperatures remains a serious challenge.Herein,we fabricated a resorcinol-formaldehyde/silica dioxide composite aerogel(RF/SiO_(2))with a three-dimensional network structure using sol-gel,atmospheric pressure drying technique as well as heat-treated processes to achieve enhanced microwave absorption capabilities in the low frequency range.The pristine RF/SiO_(2)aerogel presented a typical micropores structure with a surface area,porous volume,and density of 146.82 m^(2)/g,62.40%,and 0.28 cm^(3)/g,respectively.Remarkably,the RF/SiO_(2)aerogel showed an effective absorption bandwidth of 3.56 GHz and a minimum reflection loss value of-46.10 d B at 2.25 mm after being heat-treated at 1500°C,while the maximum effective absorption bandwidth was 3.60 GHz at 2.30 mm.The intricate three-dimensional networks possessed remarkable impedance matching,multiple attenuation mechanisms,interfacial polarization,and dielectric loss,which were attributed to the exceptional ability to absorb electromagnetic microwaves.It offered a fresh approach to creating adaptable and effective microwave absorption materials in military defense.

Visual experimental study of nanofluids application to promote CO_(2) absorption in a bubble column

The addition of dispersed-phase nanoparticles in the liquid phase can enhance the gas-liquid transfer process as the suspended nanoparticles affect the transfer process inside the fluid through microdisturbance or micro-convection effects.In this article,a high-speed digital camera was used to visualize the bubble behavior of CO_(2) in pure water and nanofluids to examine the effects of CO_(2) gas flow rate,nanoparticle solid content and type on the bubble behavior in the fluids.The CO_(2) absorption performance in three water-based nanofluids were compared in a bubbler.And the mass transfer characteristics during CO_(2) bubble absorption and the reasons for the enhanced gas-liquid mass transfer effect of nanoparticles were analyzed.The results showed that the presence of nanoparticles affected the formation process of bubbles in the fluid,shortened the bubble detachment time,reduced the detachment diameter,effectively increased the gas-liquid contact area,and improved the bubbles detachment frequency.The system with MCM-41 corresponded to a higher overall mass transfer coefficient.Uncalined MCM-41 contained surfactant that enhanced foaming behavior in water.This prevented the transfer of CO_(2) to some extent,and the CO_(2) absorption by uncalined MCM-41/H_(2)O was 5.34%higher than that by pure water.Compared with SiO_(2) nanoparticles with the same particle size and the same composition,MCM-41 had a higher adsorption capacity and better hydrophilicity due to its larger specific surface area and rich porous structure,which was more favorable to accelerate the collision between nanoparticles and CO_(2) bubbles to cause micro-convection.Under the condition of 0.1%(mass)solid content,the enhancement of CO_(2) absorption process by MCM-41 nanoparticles was more significant and improved by 16.9%compared with pure water.

Low-frequency and dual-band microwave absorption properties of novel VB-group disulphides(3R–TaS_(2))nanosheets

As electromagnetic technology advances and demand for electronic devices grows,concerns about electromagnetic pollution intensify.This has spurred focused research on innovative electromagnetic absorbers,particularly chalcogenides,noted for their superior absorption capabilities.In this study,we successfully synthesize 3R–TaS_(2)nanosheets using a straightforward calcination method for the first time.These nanosheets exhibit significant absorption capabilities in both the C-band(4–8 GHz)and Ku-band(12–18 GHz)frequency ranges.By optimizing the calcination process,the complex permittivity of TaS_(2)is enhanced,specifically for those synthesized at 1000℃for 24 h.The nanosheets possess dual-band absorption properties,with a notable minimum reflection loss(RLmin)of41.4 dB in the C-band,and an average absorption intensity exceeding 10 dB in C-and Ku-bands,in the absorbers with a thickness of 5.6 mm.Additionally,the 3R–TaS_(2)nanosheets are demonstrated to have an effective absorption bandwidth of 5.04 GHz(3.84–8.88 GHz)in the absorbers with thicknesses of 3.5–5.5 mm.The results highlight the multiple reflection effects in 3R–TaS_(2)as caused by their stacked structures,which could be promising low-frequency absorbers.

An integrated technology for the absorption and utilization of CO_(2)in alkanolamine solution for the preparation of BaCO_(3)in a high-gravity environment

In this study,an integrated technology is proposed for the absorption and utilization of CO_(2)in alkanolamine solution for the preparation of BaCO_(3)in a high-gravity environment.The effects of absorbent type,high-gravity factor,gas/liquid ratio,and initial BaCl2concentration on the absorption rate and amount of CO_(2)and the preparation of BaCO_(3)are investigated.The results reveal that the absorption rate and amount of CO_(2)follow the order of ethyl alkanolamine(MEA)>diethanol amine(DEA)>N-methyldiethanolamine(MDEA),and thus MEA is the most effective absorbent for CO_(2)absorption.The absorption rate and amount of CO_(2)under high gravity are higher than that under normal gravity.Notably,the absorption rate at 75 min under high gravity is approximately 2 times that under normal gravity.This is because the centrifugal force resulting from the high-speed rotation of the packing can greatly increase gas-liquid mass transfer and micromixing.The particle size of BaCO_(3)prepared in the rotating packed bed is in the range of 57.2—89 nm,which is much smaller than that prepared in the bubbling reactor(>100.3 nm),and it also has higher purity(99.6%)and larger specific surface area(14.119 m^(2)·g^(-1)).It is concluded that the high-gravity technology has the potential to increase the absorption and utilization of CO_(2)in alkanolamine solution for the preparation of BaCO_(3).This study provides new insights into carbon emissions reduction and carbon utilization.

Structural and microwave absorption properties of CoFe_(2)O_(4)/residual carbon composites

Electromagnetic interference,which necessitates the rapid advancement of substances with exceptional capabilities for bsorbing electromagnetic waves,is of urgent concern in contemporary society.In this work,CoFe_(2)O_(4)/residual carbon from coal gasification fine slag(CFO/RC)composites were created using a novel hydrothermal method.Various mechanisms for microwave absorption,including conductive loss,natural resonance,interfacial dipole polarization,and magnetic flux loss,are involved in these composites.Consequently,compared with pure residual carbon materials,this composite offers superior capabilities in microwave absorption.At 7.76GHz,the CFO/RC-2 composite achieves an impressive minimum reflection loss(RL_(min))of-43.99 dB with a thickness of 2.44 mm.Moreover,CFO/RC-3 demonstrates an effective absorption bandwidth(EAB)of up to 4.16 GHz,accompanied by a thickness of 1.18mm.This study revealed the remarkable capability of the composite to diminish electromagnetic waves,providing a new generation method for microwave absorbing materials of superior quality.

Construction of enhanced multi-polarization and high performance electromagnetic wave absorption by self-growing ZnFe_(2)O_(4)on Cu_(9)S_(5)

The development of 3D structural composites with electromagnetic(EM)wave absorption could attenuate EM waves.Herein,magnetized flower-like Cu_(9)S_(5)/ZnFe_(2)O_(4)composites were fabricated through a multistep hydrothermal method.The crystallographic and surface phase chemical information,morphological structure,and magnetic and EM parameters of the composites were analyzed.The prepared Cu_(9)S_(5)/ZnFe_(2)O_(4)composites have multiple loss paths for EM waves and present an overall 3D flower-like structure.The Cu_(9)S_(5)/ZnFe_(2)O_(4)composites exhibit a minimum reflection loss of-54.38 dB and a broad effective absorption bandwidth of 5.92 GHz.Through magnetization,ZnFe_(2)O_(4)particles are self-assembled and grown on the surfaces of Cu_(9)S_(5).Such a modification is conducive to the generation of additional cross-linking contact sites and the effective introduction of a large number of phase interfaces,crystalline defects,special three-dimensional flower-like structures,and magneto-electrical coupling loss effects.Moreover,the synergistic effect of multiple loss strategies effectively improves EM wave absorption by the material.This work can provide a strategy for the use of magnetizationmodified sulfide composite functional materials in EM wave absorption.

电厂粉煤灰、炉渣和污泥复合陶粒对低浓度Pb^(2+)的吸附特性

针对重金属污染具有来源广、危害大等特点,通过以电厂废物(粉煤灰、炉渣)和脱水污泥为原料制备一种高效且价廉的陶粒吸附剂,采用吸附影响因素实验、解吸再生实验、吸附动力学模型和等温吸附模型的拟合以及陶粒表征分析,探究陶粒对Pb^(2+)的吸附特性,同时为实现废物资源化利用提供新思路.结果表明:陶粒去除Pb^(2+)的较佳吸附条件为粒径4 mm、pH 4.5~5.0、吸附时间360 min、吸附温度25℃.陶粒再生所用较佳解吸剂为0.5 mol/L的HCl溶液,较佳解吸时间和次数分别为120 min和5次,解吸5次后陶粒对Pb^(2+)的去除率为92.67%.此吸附过程更好地遵循了准二级动力学模型和Freundlich等温吸附模型.陶粒上的O-H、Si-O和金属氧化键在吸附Pb^(2+)的过程中起主要作用.陶粒吸附Pb^(2+)后,出现了新的物相Pb_(2)Cl_(3)OH和PbO,陶粒与Pb^(2+)之间发生化学吸附,为自发进行的放热反应.陶粒处理实际废水中Pb^(2+)的去除率可达93.70%,Pb^(2+)浓度由3.74 mg/L降至0.24 mg/L.研究显示,电厂粉煤灰、炉渣和污泥复合陶粒对Pb^(2+)具有一定的去除效果,可为以固体废物为原料制备的吸附剂在重金属废水处理应用中提供数据支撑.

磁性三乙烯四胺/单宁树脂对Cu^(2+)、Pb^(2+)的吸附性能研究

利用曼尼希反应将三乙烯四胺(TETA)固化到单宁(TA)基体表面,热溶剂法制得磁性单宁基树脂(MTETA-TA)。通过红外光谱、扫描电镜、比表面积及孔隙度分析仪、振动样品磁强计对M-TETA-TA进行表征,表明M-TETA-TA具有疏水性强、比表面积大的优势,Fe_(3)O_(4)的成功引入有效解决吸附剂回收难的问题。对含Cu^(^(2+))、Pb^(2+)废水溶液进行了静态吸附实验,探讨了其对金属的吸附性能。在pH为5的酸性条件下,吸附效果较好;Cu^(^(2+))和Pb^(2+)吸附动力学均符合准二级反应动力学模型,主要为化学吸附;Cu^(^(2+))的吸附等温线符合Langmuir模型,属单层吸附,理论吸附最大值为173.33 mg·g^(-1);Pb^(2+)的吸附等温线符合Sips模型,属多层吸附,理论吸附最大值为217.14 mg·g^(-1)。推测M-TETA-TA对Pb^(2+)的吸附除了螯合、氧化还原等化学反应,还存在静电和离子交换作用,氨基和酚羟基为主要参与官能团。循环再生5次后,仍有较高的吸附性能和磁性强度。

玉米秸秆复合高吸水树脂的制备及对Pb^(2+)的吸附研究

以来源丰富的玉米秸秆、高岭土为原料,以丙烯酸、丙烯酰胺为聚合单体,通过水溶液聚合法制备了复合高吸水树脂,并用红外光谱(FT-IR)和扫描电镜(SEM)对其结构进行了表征分析。利用合成的复合高吸水树脂对含Pb^(2+)模拟废水进行了吸附研究,考察了复合高吸水树脂用量、Pb^(2+)初始浓度、吸附时间和溶液pH及对Pb^(2+)去除率的影响,最优条件下复合高吸水树脂对Pb^(2+)的去除率达88.57%,吸附Pb^(2+)后的复合高吸水树脂经处理后可循环使用。

一种苝酰亚胺Pb^(2+)荧光探针的合成及其选择性识别

以四氯苝酐、3-氨甲基吡啶为原料,设计并合成了一种可选择性识别Pb^(2+)的新型苝酰亚胺类荧光探针N,N-(吡啶-3-甲基)-1,6,7,12-四氯-3,4:9,10-苝二酰亚胺(PDI-MBD)。采用质谱、核磁等检测手段对其分子结构进行了表征,通过紫外和荧光光谱法对目标化合物PDI-MBD在N-甲基-2-吡啶烷酮(NMP)/H2O溶液中,对Pb^(2+)的识别性能进行了研究,其光谱性能和对Pb^(2+)识别研究显示,探针PDI-MBD自身的荧光较弱,但与金属离子Pb^(2+)配位反应后荧光显著增强,为配位反应前的10倍,但随着时间的延长,之后又出现荧光猝灭的现象。探针PDI-MBD表现出对溶液中的Pb^(2+)具有良好的选择性识别,且灵敏度高。研究发现,Pb^(2+)在0.1×10^(-5)~5×10^(-5)mol/L的浓度范围内与探针的荧光强度存在良好的线性关系;Pb^(2+)的最低检测限为0.5×10^(-6)mol/L。抗干扰试验证明加入其他常见金属离子后,探针PDI-MBD对Pb^(2+)的荧光信号无显著变化,不易受其他金属离子的影响。说明PDI-MBD可作为Pb^(2+)荧光探针,具有较优的选择性和较强的灵敏度,建立了一种检测Pb^(2+)的分析方法。

酸改性污泥基复合陶粒对Pb^(2+)的吸附性能研究

以污泥、磷尾矿和赤泥为原料制备陶粒,用盐酸、硝酸和柠檬酸进行改性,研究陶粒对水中Pb^(2+)的吸附效果,并通过扫描电镜(SEM)、表面基团、零电荷点(pHPZC)和傅里叶红外光谱(FTIR)分析陶粒对Pb^(2+)的吸附机理。结果表明,低浓度盐酸或硝酸改性陶粒对Pb^(2+)的去除率更好,柠檬酸改性陶粒对Pb^(2+)的去除率低于未改性陶粒。酸改性陶粒具有比表面积大、孔隙结构发达、酸性基团含量多、等电点低等特点,对Pb^(2+)的吸附同时存在物理吸附和化学吸附过程,可用作含Pb^(2+)废水的处理材料。

碳化处理对再生微粉吸附Pb^(2+)行为与机理的影响

随着工业的发展,大量含铅废弃物被排放到环境中,给水体带来了严重的污染。本研究采用经碳化处理的再生混凝土微粉(CRCF)作为吸附剂,针对硝酸铅配制的铅污染溶液开展吸附试验,并测试分析了吸附剂的物相、微观结构和稳定性。研究表明,CRCF对Pb^(2+)具有良好的吸附效果,24 h后可达到93.1%(质量分数,下同)的去除率;CRCF对Pb^(2+)的吸附稳定性较高,吸附后仅有极少量的Pb^(2+)浸出;吸附反应中,Pb^(2+)静电吸附在CRCF表面,与CRCF发生离子交换并在表面形成碳酸盐沉淀,最终主要以碳酸盐的形式固定在CRCF中;CRCF可作为一种低成本的Pb^(2+)高效吸附剂,可有效应用于含铅废水的治理,实现废物资源化再利用。

Pb^(2+)对掺杂硼硅酸盐玻璃中CsPbBr_(3)钙钛矿量子点发光性能的影响

硼硅酸盐玻璃包覆钙钛矿CsPbBr_(3)量子点(PQDs@glass)能够大幅提高PQDs的稳定性,使其在LED照明和显示技术中拥有广泛的应用空间。然而,玻璃包覆的同时也导致了PQDs发光强度与量子产率降低。本工作为提高其发光强度探讨了热诱导温度及Pb^(2+)的含量对PQDs@glass结构的影响,当热诱导温度为460℃,Pb^(2+)浓度为6 mol时,其发光强度最高。研究发现,Pb^(2+)浓度的增加会导致玻璃网状结构的致密化,改变玻璃组分的扩散行为,影响PQDs的析晶过程,导致PQDs@glass发光强度的变化。本工作得到量子产率高达95.6%的PQDs@glass,并实现了硼硅酸盐玻璃基质内PQDs的尺寸可控制备。结果表明,PQDs尺寸分布在10 nm左右,超过86%的颗粒尺寸在6~14 nm内,且具有优越的稳定性,经历10次室温至200℃热循环后,发光强度仍能保持初始强度的98.9%。最后,为了验证其在LED照明及显示领域的应用,将制备的量子点微晶玻璃粉料与二甲基硅氧烷(PDMS)混合,得到的LED器件性能优异,色域范围覆盖110%sRGB。本研究为PQDs@glass的大规模制备及其在LED器件领域的应用奠定了基础。

Pb^(2+)的检测及去除方法研究进展

近年来铅污染问题日益加重,需要高效、准确、快速的Pb^(2+)检测方法。总结了Pb^(2+)的危害及原子吸收光谱法、高分辨率连续源石墨炉原子吸收光谱法、紫外可见分光光谱法、电化学分析法等检测技术,并对其优缺点进行了简要说明。同时介绍了Pb^(2+)的去除方法及其实际应用,最后对该领域的发展前景进行了展望。

铁改性生物炭对黄绵土Pb^(2+)运移过程影响及模型分析

[目的]明确不同铁改性生物炭施加量下土壤重金属的运移过程,以期为黄土区土壤重金属污染防治提供理论依据。[方法]以铁改性生物炭与黄绵土质量比分别为0%(CK),1%(A_(1)),2%(A_(2)),3%(A_(3)),4%(A_(4))和5%(A_(5))6组处理为研究对象,以Pb^(2+)为示踪离子,利用室内土柱进行溶质运移模拟试验,研究了不同铁改性生物炭施加量对黄绵土中Pb^(2+)运移过程的影响并进行模型模拟。[结果](1)A_(1),A_(2),A_(3),A_(4)和A_(5)处理的饱和导水率(K_(s))比CK分别减少了6.90%,20.70%,27.60%,31.03%和37.93%,即K s随铁改性生物炭施加量增大而逐渐减小。(2)不同处理的Pb^(2+)浓度达到平衡时的总历时比CK分别延长了1.79,13.00,34.98,35.34,40.81 h,随铁改性生物炭施加量增加,重金属初始和完全穿透时间明显推迟。(3)两区模型(TRM)和对流-弥散方程(CDE)的拟合曲线均能与实测曲线较好吻合,但TRM的决定系数(R^(2))大于CDE,均方根误差(RMSE)小于CDE,因此TRM的模拟精度更高。[结论]土壤中施加铁改性生物炭能较好地减缓重金属的运移过程,对调控土壤中重金属运移及防止地下水污染具有重要作用。

Mixed‑Dimensional Assembly Strategy to Construct Reduced Graphene Oxide/Carbon Foams Heterostructures for Microwave Absorption,Anti‑Corrosion and Thermal Insulation

Considering the serious electromagnetic wave(EMW)pollution problems and complex application condition,there is a pressing need to amalgamate multiple functionalities within a single substance.However,the effective integration of diverse functions into designed EMW absorption materials still faces the huge challenges.Herein,reduced graphene oxide/carbon foams(RGO/CFs)with two-dimensional/three-dimensional(2D/3D)van der Waals(vdWs)heterostructures were meticulously engineered and synthesized utilizing an efficient methodology involving freeze-drying,immersing absorption,secondary freeze-drying,followed by carbonization treatment.Thanks to their excellent linkage effect of amplified dielectric loss and optimized impedance matching,the designed 2D/3D RGO/CFs vdWs heterostructures demonstrated commendable EMW absorption performances,achieving a broad absorption bandwidth of 6.2 GHz and a reflection loss of-50.58 dB with the low matching thicknesses.Furthermore,the obtained 2D/3D RGO/CFs vdWs heterostructures also displayed the significant radar stealth properties,good corrosion resistance performances as well as outstanding thermal insulation capabilities,displaying the great potential in complex and variable environments.Accordingly,this work not only demonstrated a straightforward method for fabricating 2D/3D vdWs heterostructures,but also outlined a powerful mixeddimensional assembly strategy for engineering multifunctional foams for electromagnetic protection,aerospace and other complex conditions.

Fe_(3)O_(4)掺杂改性电极电化学去除Pb^(2+)的效能研究

为了实现水体中Pb^(2+)的高效电化学去除,采用涂覆法将Fe_(3)O_(4)、粉末活性炭、乙炔黑和聚乙烯醇混合后负载于石墨纸上,制备得到了Fe_(3)O_(4)掺杂改性电极。采用差分柱批式反应器模式进行电化学去除Pb^(2+)实验,考察了电压、温度、运行时间、Pb^(2+)质量浓度对去除Pb^(2+)的影响并评估了电极的重复利用性和稳定性。结果表明,所制备的电极表面孔隙丰富,孔径均匀。电压为1.4 V时,运行150 min后电化学体系对Pb^(2+)的去除率达到了98.73%,延长运行时间可以显著强化Pb^(2+)的去除率。在10~35℃的温度范围内,温度升高有利于Pb^(2+)的电化学去除,电化学体系在不同的Pb^(2+)浓度下均有较好的适用性和适应性,随着Pb^(2+)初始浓度的升高,处理单位体积含Pb^(2+)废水的能耗逐渐增加,但去除单位质量Pb^(2+)的能耗反而降低,拟合结果表明Pb^(2+)的去除过程符合准一级动力学。经过8次循环后,电化学体系仍保持原有的Pb^(2+)去除效果。

基于发夹DNA动态自组装树枝状聚合物放大策略的荧光传感体系测定水中Pb^(2+)的含量

基于GR-5脱氧核酶(GR-5 DNAzyme)对Pb^(2+)的特异性识别和发夹DNA动态自组装树枝状聚合物信号放大策略,构建了一种新型无酶、高灵敏检测Pb^(2+)的荧光传感体系。分别于95℃恒温孵育合成序列扩展GR-5 DNAzyme复合物(GR-5E-S,由GR-5 DNAzyme酶链GR-5E和底物链GR-5S合成)以及Y型骨架(由骨架链Y1、Y2、Y3合成),于25℃恒温孵育合成发夹三聚体(由Y型骨架和发夹链H1、H2、H3合成,其中发夹链H1上修饰有荧光团和猝灭团)。将水样4μL添加到96μL含400 nmol·L^(-1)GR-5E-S,400 nmol·L^(-1)发夹三聚体的反应溶液中,于25℃孵育40 min。当水样中存在Pb^(2+)时,GR-5E-S识别Pb^(2+),底物链被切割,酶链和底物链分开并释放出目标链T,目标链T与发夹链H1杂交触发动态自组装过程,生成树枝状聚合物,于520 nm处测量荧光强度。结果显示:建立的荧光传感体系可在40 min内完成检测;Pb^(2+)的浓度在0.1~10.0 nmol·L^(-1)内与对应的传感体系的荧光强度呈线性关系,检出限(3s/k)为19 pmol·L^(-1);按照标准加入法进行回收试验,回收率为98.0%~108%,测定值的相对标准偏差(n=5)不大于15%。