Soluble Lead Research Articles

Conformal coating of PbO2 around boron doped diamond coated carbon felt positive electrode for stable and high-capacity operation of soluble lead redox flow battery

The commercialization of soluble lead redox flow battery (SLRFB) is challenging due to its limited cycle life, lower areal capacity, Pb dendrite formation, and positive electrode corrosion. However, improvements are made to a certain extent by employing additives chemistry in terms of electrolyte modification. One of the major problems in SLRFB is carbon corrosion at higher current densities. Therefore, electrode modification, specifically on the positive side, is required to improve the cyclability of SLRFB further. There is minimal literature on this aspect.Given this, efforts are being made to enhance the electrochemical performance of SLRFB by employing a boron doped diamond (BDD) coated carbon felt (CF) as the positive electrode. The BDD coated CF electrode possesses a high surface area (7.1 m2g−1) compared to bare CF (0.6 m2g−1), i.e., BDD creates porous morphology, which enables a high mass transfer and hence reduces concentration polarisation. BDD coating on the CF delays the OER and reduces the overpotential for PbO2 deposition/dissolution. The cell with BDD coated CF electrode is successfully cycled for >300 charge/discharge cycles @ 40 mA cm−2 with average coulombic efficiency (CE), voltage efficiency (VE) and energy efficiency (EE) of 97 %, 71 % and 69 % respectively. The EE is improved by 8 % in the presence of BDD coated CF as compared to CF electrode. SLRFB cell with BDD coated CF electrode has reached 80 mAh cm−2 areal capacity.

Role of Side Reaction Involving PbOx in Soluble Lead Redox Flow Battery: Effect on Cyclability

Soluble lead redox flow battery (SLRFB) has been an active subject of investigation in the past two decades because of its high energy efficiency (~70%) and charge efficiency (~90%) [1]. During charging, Pb2+ ions deposit as solid lead dioxide (PbO2 ) on anode and solid lead (Pb) on cathode, respectively. These features permit a membrane-less single-compartment design, making SLRFB a cost-effective electrochemical energy storage device. Discharge occurs by electro-dissolution of these solids, regenerating the electrolyte. The limited cycle-life of SLRFB is its current deployment challenge (best achieved about 100 cycles [2]). The shedding of solid lead dioxide over cycling is an indirect irreversible loss of active material from the electrolyte, the reason for SLRFB’s limited cyclability.Mathematical models link the deposit formation and the two-step charging potential profile through a side reaction involving PbO and PbO2 [3-5]. Morphological changes in deposit during cycling have been reported and presented as an alternate justification to the two-step potential profile [6]. To clarify these, we tested the role and feasibility of re-oxidation of solid PbO on cycling under varied conditions using an in-house prepared Nafion membrane-divided cell. We show that the charging through side reaction does not occur without the availability of Pb2+ near the electrode. We also show that the observations are independent of the electrodes’ age, the amounts of PbO and PbO2 present, and the applied current density. We obtained FESEM images of anode after short re-charging in a single-compartment design. We observed the formation of a new phase, plausibly lead dioxide from Pb2+ ions, leaving the solid residue almost unaffected. These findings challenge the idea of charging sustained in part by the oxidation of PbO through the side reaction. The deposit, constituted by whisker-like particles (thickness~200 nm), appears weak and layered. Gas evolution reactions known to occur under the limited availability of Pb2+ ions may promote residue disintegration. These observations lead us to hypothesize that cycling leads to irrecoverable residue accumulation, which may negligibly participate in further re-oxidation through the side reaction. These cumulative effects, accompanied by formation of a new phase at every charging, appear to contribute significantly to restricting SLRFB to a short cycle-life. These features raise concerns about the prevailing hypotheses about SLRFB dynamics and suggest need for strict design and operational controls to avoid residue buildup.

Recovering metallic lead from spent lead paste by slurry electrolysis

Spent lead paste, the most challenging component of discarded lead-acid batteries, contains approximately 70 % Pb. Improper handling of lead-acid battery waste poses severe risks to both the environment and human health. Here, we present a novel and short process for directly recycling metallic Pb from spent lead paste by chlorine slurry electrolysis and investigate the parameters that affect Pb recovery rate and cathodic current efficiency. Our experiments showed that under optimal conditions (250 g/L NaCl, 0.8 mol/L HCl, 10 g/L Pb2+, 30 A/m2, 40 g/L pulp concentration, 65 °C, and 12 h), the Pb recovery rate and cathodic current efficiency were, respectively, 90.54 and 85.25 %. During slurry electrolysis. Cl- combined with Pb in spent lead paste in the anode chamber, converting lead oxides and insoluble PbSO4 into soluble lead chloride complexes ([PbCl3]-, [PbCl4]2-). Driven by the electric field and concentration gradient, the lead chloride complex ions then migrated to the cathode region, where they were reduced to metallic Pb with a purity higher than 99 %. The application of this cost-effective and efficient novel method can contribute to the sustainable reuse of waste lead-acid batteries and other Pb-bearing scrap.

A Recent Trends on Green Synthesis and Bioactivity of Imidazole

Imidazole is a five-membered, planar heterocyclic ring made up of 3C, 2N, and N in the 1st and 3rd places. Purine, histamine, histidine, and nucleic acid are only a few significant natural compounds that contain the imidazole ring. It is utilised as a cure to optimize the solubility and bioavailability properties of proposed weakly soluble lead compounds since it is an aromatic chemical that is polar and ionizable and so improves the pharmacokinetic features of lead molecules. Derivatives of imidazole have a special place in medicinal chemistry. An essential synthesis technique in the process of discovering new drugs is the integration of the imidazole nucleus. Due to the remarkable therapeutic efficacy of medications related to imidazole, medicinal chemists have been inspired to create numerous innovative chemotherapy agents. This review summarized the work that has been done in recent years about different synthetic approaches of imidazole derivatives and their potential activity as anti-HIV, anticancer, anticovid, antifungal, antidiabetic, antidepressant, antioxidant, and antituberculosis.

An Innovative Concept of Membrane-Free Redox Flow Batteries with Near-Zero Contact Distance Between Electrodes.

Given that the ion-exchange membrane takes up more than 30% of redox flow battery (RFB) cost, considerable cost reduction is anticipated with the membrane-free design. However, eliminating the membrane/separator would expose the membrane-free RFBs to a higher risk of short-circuits, and the dendrite growth may aggravate this issue. The current strategy based on expanding distances between electrodes is proposed to address short-circuit issues. Nevertheless, this approach would decrease the energy efficiency (EE) and could not restrain dendrite growth fundamentally. Herein, an inexpensive and electron-insulating boron nitride nanosheets (BNNSs)-Nylon hybrid interlayer (BN/Nylon) is developed for general membrane-free RFBs to achieve "near-zero distance" contact between electrodes. And the Lewis acid sites (B atoms) in BNNS can interact with the Lewis base anions in electrolytes, enabling a reduced Pb2+concentration gradient. Additionally, the ultrahigh thermal conductivity and mechanical strength of BNNSs promote the uniform plating/stripping process of Pb and PbO2. Compared with conventional soluble lead RFBs, introducing BN/Nylon interlayers boosts EE by ≈38.2% at 25mAcm-2, and extends the cycle life to 100 cycles. This innovative strategy premieres the application of the BN/Nylon interlayer concept, offering a novel perspective for the development of general membrane-free RFBs.

Long-term effectiveness of lead precipitation as carbonate and its stability under acidic conditions by using activated serpentine mineral

Utilization of readily accessible serpentine mineral, for lead removal from wastewater is a sustainable strategy, but the adsorption capacity of the raw serpentine is limited due to its small interlayer spacing and low surface reactivity, not to say the cases under acidic conditions. In this study, natural serpentine was simply ball-milled to obtain enhanced reactivity and dissolution due to the generation of various lattice defects, which allowed the highly efficient lead fixation even under acidic conditions (at initial pH of 3), compared to that driven by the surface adsorption. Characterizations demonstrated the continuous dissolution of serpentine in solution with the reaction time prolonged, inducing the heterogeneous precipitation of significant (basic) lead carbonate on serpentine surface with an aid of even very dilute atmospheric CO2, which worked as the dominated mechanism for enhancing the whole lead fixation efficiency. Results showed that more than 99.5 % of soluble lead could be immobilized within 1 ∼ 2 h with serpentine dosage of 0.5 g/L under low concentration (5 ∼ 100 mg/L), with a high lead fixation capacity about 1782.9 mg/g after 48 h under high concentration (1000 mg/L). Moreover, the stability of the Pb-bearing sediment under acidic exposure (pH 3) for 24 h was confirmed, and the dissolved lead from chloride and sulfate salts could also be immobilized using the as-proposed strategy. Altogether, these findings demonstrated the high efficiency and long-term effectiveness of lead fixation on the ball-milled serpentine, which makes it a promising candidate for application to green remediation of heavy metal contaminations in various sites along with the utilization of waste mineral resources.

Effect of carbon-foam composite-coated electrode on the power storage performance of soluble lead flow batteries

In this study, we meticulously fabricated a carbon-foam composite-coated electrode through a plating electroless copper technique, which was subsequently followed by electrodeposition of lead on a carbon-foam matrix. The investigation focused on exploring the physicochemical properties of the electrodes and the cycling performances of soluble lead flow batteries. In comparison to a conventional graphite electrode, the carbon-foam composite-coated electrode exhibited superior characteristics, including a higher specific surface area characterized (282 m2 g−1) and a higher conductivity (915.37 S cm−1). The utilization of cyclic voltammetry and electrochemical impedance spectroscopy demonstrated a notable enhancement in the reversible activity of the Pb/Pb2+ couple on the novel electrode. The porous structure of the novel electrode facilitated efficient charge dispersion between the poles and effectively suppressed the dendrite growth of the negative lead. As indicated by the result, the battery incorporating the novel electrode exhibited an energy efficiency exceeding 90.0 %, an extended charge duration of 6 h, and an elevated charge/discharge rate of 60 mA cm−2. The cell employing the CFCC-E had been successfully cycled for over 650 cycles with an average Coulombic efficiency of 94.5 % when cycled at 60 mA cm−2 for 1 h.

Properties of a Soluble Lead Flow Battery Recycled with Hydrogen Peroxide

AbstractThe service life of soluble lead flow batteries can be extended by periodic addition of H2O2, especially when it failed. However in first few cycles after H2O2 treatment, its coulombic efficiency is very low. To clarify it, the properties of electrode and electrolyte, and cycle performance have been systematically analyzed. It has been found that the negative/positive electrode reactions have serious overpotentials during early charging due to oxygen, which are produced and dissolved into the electrolyte during H2O2 treatment. With increasing the cycle number, the polarization degree decreases to the normal level of the battery. To solve it, oxygen is removed using argon after H2O2 treatment. The flow cell is normally recovered in the cycling performance. The average coulomb efficiency is 94.5±5.8 % for 500 times. After H2O2 treatment and oxygen removal, it exhibits a good cycling performance at the average coulomb efficiency of 93.9±4.2 % for another 500 times.

Simultaneous recovery of Fe2O3 and PbCl2 from hazardous jarosite residues via hydrothermal phase transformation with NaCl

Jarosite residue is a typical hazardous waste produced in the zinc hydrometallurgy industry. In this study, both iron and lead were recovered from jarosite residues through the use of hydrothermal treatment with NaCl as a mineralizer. By controlling crystal site replacement, phase transformation, and lead species, Na+ was able to replace Pb2+ sites, resulting in the release of Pb2+ from Na-Pb jarosite and its transformation into Na-jarosite. During hydrothermal treatment, Na-jarosite was then easily converted into Fe2O3. Furthermore, the high concentration of Cl− captured the released Pb2+ to form soluble lead chloride complexes, which separated and remained in the liquid phase, leading to the successful separation of lead and iron. Crystallization through evaporation allowed recovery of lead as PbCl2. The separation efficiency of lead in jarosite residues was up to 92.6%, making this research a significant contribution to the effective recovery of iron and lead from jarosite residues.

Life span enhancement of low cost soluble-lead-redox-flow battery using high performance meso-graphite spherules/AC anode

Limited life span and sluggish kinetics have impeded the large-scale commercialization of the emerging soluble lead flow battery (SLFB). In this perspective, we have developed a promising anode with rapid charge transport characteristics and good reversible chemical reactions. A graphite spherules-based composite anode modified with an activated carbon additive can restrain the poor electrodeposits adhesion, improve the charge transfer kinetics for more balanced redox chemistry and prevent cell failure. An optimized composite anode configuration assisted in enhanced exchange current density and demonstrated high coulombic efficiency (>80 %) with a long-life span (813 cycles), additionally generating meagre precipitation of the deposits (0.53 g). The morphological and kinetic interpretation of the cycled electrodes further elucidates that the modified SLFB anode enables faster dissolution of the Pb to Pb+2, allowing the flow battery to stock the stored capacity to meet the future energy requirements efficiently. The proof-of-concept modified anode achieved through this work would reliably open new approaches to developing better electrodes for stable and efficient SLFB systems to help modularize batteries for grid-scale exploration.

Valorisation of original nanostructured lead oxides thin films issued from an innovating electrochemical depollution process: Application to the total electro-mineralisation of glyphosate

Glyphosate is a very problematic pollutant in the world. This study presents a simple treatment to degrade it until total mineralisation with no production of AMPA (aminomethylphosphonic acid), its main by-product more toxic and persistent, by using original nanostructured lead oxides thin films. The synthesis conditions of these materials were determined previously in relation to an innovating electrochemical depollution process of water polluted by soluble lead. Different parameters were evaluated such as pH, initial concentration, lead oxide type and consequently its particular morphology. The solutions were systematically analysed by ion chromatography to determine the concentrations of organic pollutants and ionic species produced, and by UV–visible spectroscopy to quantify released lead during process. The thin films were characterized by XRD, SEM and EDS, before and after interaction. The Pb-04 sample type (pure β-PbO2 with cubic needles nanostructures) seems particularly efficient to obtain a total mineralisation with a mineralisation capacity equal to (1127 ± 56) mg of glyphosate/g of material. Moreover, lead was not released in solution due to a total regeneration with the similar crystalline structure. These results are very promising for potential valorisation of heavy metals wastes for future applications at room temperature and very low electrical inputs.

Effect of stagnation period and flow rate on soluble and particulate Pb leaching in copper pipe water distribution systems

Extremely high lead level in tap water caused by particulates has attracted increasing attention in recent years. Despite extensive research on the role of particulate Pb in water supply systems with lead service lines, little information is available on the role of particulate Pb in copper (Cu) water distribution systems. In this study, the dissolved, colloidal, and particulate lead and copper concentrations in representative prototype copper pipe water distribution systems with leaded solder joints and brass fixtures are measured. The effects of flow rate and stagnation time on metal fractionation are investigated. For each experimental scenario, all the water that stagnated inside the system is sampled to have a comprehensive understanding of lead contamination. Sampled at flow rates of 200–250 mL/s, the soluble lead and copper make up 60–96 % of the total concentration in the samples after hours of stagnation. More than half of the Pb and Cu particles are larger than 0.8 μm. Higher flow rates result in substantial increases in particulate metal concentrations but have no apparent effect on dissolved metals. The soluble and particulate copper concentrations (∼ 100–250 μg/L) both increase with stagnation time. For the case of Pb, while the particulate concentration increases (up to ∼ 40 μg/L after 12 h), the soluble concentration does not change significantly beyond 4 h; this can be attributed to the different solubilities of Pb (∼ 20 μg/L) and Cu (∼ 200 μg/L) in tap water. The results also show that particulates suspended by clean “once through” water (without prior stagnation) can lead to high levels of Pb contamination (> 10 μg/L).

Issues Concerning Manufacture and Recycling of Lead

This article gives an overview of historical and present uses of lead against the backdrop of gradual realization that lead is an environmental hazard. In this paper the lead in the lead-acid batteries is investigated from the view of its present use. This use continues because there does not exist economical and practical alternative to lead for this purpose. In fact the use is still steadily increasing. This may not be a concern as it has been demonstrated that in countries with strong economies, recycling of lead from the batteries can near 100%. Here, we take a look at reality, by comparing select countries on both sides of the economic spectrum. In poorer countries, recycling suffers more on the safe and clean side of the process. Historical uses of lead are also reviewed, as well as a new approach of using lead compounds in soluble lead flow batteries.

Quantitative proteomic analyses of a Pb-adapted Tetrahymena thermophila strain reveal the cellular strategy to Pb(II) stress including lead biomineralization to chloropyromorphite

A strain of the protozoan ciliate Tetrahymena thermophila adapted to increasing Pb(II) concentrations over two years has shown that one of the resistance mechanisms to this extreme metal stress is the lead biomineralization to chloropyromorphite, one of the most stable minerals in the earth's crust. Several techniques such as microanalysis coupled to transmission and scanning electron microscopy (X-Ray Energy Disperse Spectroscopy), fluorescence microscopy and X-ray power diffraction analysis have revealed the presence of chloropyromorphite as crystalline aggregates of nano-globular structure, together with the presence of other secondary lead minerals. This is the first time that the existence of this type of biomineralization in a ciliate protozoan is described. The Pb(II) bioremediation capacity of this strain has shown that it can remove >90 % of the toxic soluble lead from the medium. A quantitative proteomic analysis of this strain has revealed the main molecular-physiological elements involved in adaptation to Pb(II) stress: increased activity of proteolytic systems against lead proteotoxicity, occurrence of metallothioneins to immobilize Pb(II) ions, antioxidant enzymes to mitigate oxidative stress, and an intense vesicular trafficking presumably involved in the formation of vacuoles where pyromorphite accumulates and is subsequently excreted, together with an enhanced energy metabolism. As a conclusion, all these results have been compiled into an integrated model that could explain the eukaryotic cellular response to extreme lead stress.

Effect of porous nature of anode on the performance of the soluble lead redox flow battery: A modeling and simulation study

A novel hybrid model consisting of two models, (1) a freshly developed porous electrode model and (2) a planar electrode model, is proposed for the soluble lead redox flow battery (SLRFB). The model accounts for simultaneous variations in ionic concentrations and potential fields in the electrolyte. It also accounts for variations in porosity, conductivity, and specific surface area at the porous anode due to the deposition/dissolution of the solids. The developed model is consistent with the solid′s deposition/dissolution mechanism. Hence, the choice of the model among the two for the simulation of a particular charge or discharge cycle follows naturally. Predictions of the model are validated using experimental data available in the literature. The model predictions suggest that the porous nature of the anode not only controls almost every feature of the battery characteristics but also governs the overall cycle life of the battery. Based on the insights developed using the model predictions, a necessary condition is derived for the battery operating procedure to achieve longer cycle life.

Predicting the cost of a 24 V soluble lead flow battery optimised for PV applications

Providing reliable electricity from small-scale renewable power is an important challenge for emerging economies. The soluble lead flow battery (SLFB) is a promising battery for this application, as it has a simple architecture making it relatively robust, and a lifetime of 2000 cycles demonstrated at the cell level. Also, the electrolyte is manufacturable directly from spent lead acid batteries. There is a need for techno-economic models to allow the cost/performance of a complete system to be defined and optimised.Such a model is defined here for the first time and used in a multi-objective optimisation to design a 24 V system for a charging hub in Sierra Leone. A 4 h duration was found to be optimal, and electrolyte for a 3.5 kW/14 kWh system would fit in a 1000 L IBC.Methanesulfonic acid was found to be the largest cost component of the 4 h system, with graphitic bipolar plates next. Both have low raw material costs, and in an optimistic scenario a total component cost of <£50/kWh would be achieved, half that of current NMC Li-ion cells. The greatest technical risk to achieving low cost is deposit thickness of lead dioxide. This important research gap should be addressed.

Repeated home drinking water sampling to improve detection of particulate lead spikes: a simulation study

BackgroundLead can be present in drinking water in soluble and particulate forms. The intermittent release of lead particulates in drinking water can produce highly variable water lead levels (WLLs) in individual homes, a health concern because both particulate and soluble lead are bioavailable. More frequent water sampling would increase the likelihood of identifying sporadic lead “spikes,” though little information is available to aid in estimating how many samples are needed to achieve a given degree of sensitivity to spike detection.ObjectiveTo estimate the number of rounds of tap water sampling needed to determine with a given level of confidence that an individual household is at low risk for the intermittent release of lead particulates.MethodsWe simulated WLLs for 100,000 homes on 15 rounds of sampling under a variety of assumptions about lead spike release. A Markovian structure was used to describe WLLs for individual homes on subsequent rounds of sampling given a set of transitional probabilities, in which homes with higher WLLs at baseline were more likely to exhibit a spike on repeated sampling.ResultsAssuming 2% of homes had a spike on the first round of sampling and a mid-range estimate of transitional probabilities, the initial round of sampling had a 6.4% sensitivity to detect a spike. Seven rounds of sampling would be needed to increase the sensitivity to 50%, which would leave unrecognized the more than 15,000 homes that intermittently exhibit spikes.SignificanceFor assessing household risk for lead exposure through drinking water, multiple rounds of water sampling are needed to detect the infrequent but high spikes in WLLs due to particulate release. Water sampling procedures for assessment of lead exposure in individual homes should be modified to account for the infrequent but high spikes in WLL.ImpactIt has been known for decades that intermittent “spikes” in water lead occur due to the sporadic release of lead particulates. However, conventional water sampling strategies do not account for these infrequent but hazardous events. This research suggests that current approaches to sampling tap water for lead testing identify only a small fraction of homes in which particulate spikes occur, and that sampling procedures should be changed substantially to increase the probability of identifying the hazard of particulate lead release into drinking water.

An Overview of Imidazole, Derivatives Ofimidazole and its Pharmacological Applications

In recent decades, many studies have been carried out on heterocycles, especially imidazole rings. The pharmacological properties such as antibacterial, antifungal, anticancer, antiviral and antidiabetic properties Apart from that, there are few side effects. The search for new biologically active imidazoles remains an area of interest An overview of medicinal chemistry. This white paper aims to collect and explain a wealth of information. Antibacterial profile of imidazole. Therefore, it can be used for future development to obtain new effective drug molecules. These heterocycles are important building blocks of functional molecules used in various fields. Used on a daily basis. Emphasis was placed on the bonds that form during the formation of imidazole. The usefulness of these methods is based on functional group compatibility. Processes around the ring and the resulting permutation patterns are described, including domain descriptions. Limitations, Reaction Mechanisms, and Future Challenges. The imidazole ring is part of several important natural products Products containing purines, histamine, histidine, nucleic acids. as polar and ionic Aromatic compounds that improve the pharmacokinetic properties of lead molecules Used as a remedy to optimize poorly proposed solubility and bioavailability parameters soluble lead molecule. Imidazole derivatives occupy a unique position in the art medicinal chemistry. Imidazole drugs have expanded the scope of eliminating various dispositions in clinics dose.

Electrochemical properties of electrolyte for lead fluoroborate redox flow battery prepared with recovered lead

The electrochemical properties of electrolyte for soluble lead flow battery(SLFB) are a key factor for the improvement of its performance. Pb(BF4)2 in which Pb2+ ions are highly soluble is cheaper and more stable than conventional Pb(CH3SO3)2. This paper presents the electrochemical properties of HBF4 and Pb(BF4)2 prepared with recovered lead for the electrolytes of SLFB. The density difference of reagent grade and recovered lead electrolytes is less than 0.05 g/cm3 and their viscosities increase up to 132 %, 120 %, respectively when concentration of Pb(BF4)2 changes from zero to 2.0 mol·dm−3. The conductivity of 1.5 mol·dm−3 electrolyte prepared with recovered lead has a peak when concentration of HBF4 is less than 1.0 mol·dm−3. The results of cyclic voltammetry, linear sweep voltammetry and constant current charge/discharge test showed that impurities of recovered lead exert insignificant influences on the Pb2+/Pb and Pb2+/PbO2 reactions. These results are promising to apply recovered lead to SLFB.

Photoluminescence Sensing of Soluble Lead in Children’s Crayons Using Perovskite Nanocrystal In Situ Growth on an Aluminum Hydroxide Layer

In this study, a fluorescence sensing approach for lead ion (Pb2+) was developed using in situ growth of methylamine lead bromine (MAPbBr3) perovskite on an aluminum hydroxide (Al(OH)3) thin layer. The Al(OH)3 thin layer could be obtained on a glass slide by liquid phase deposition and is of a large specific surface area and insoluble in water. After sulfhydryl functionalization, the Al(OH)3 thin layer reveals effective adsorption and excellent enrichment ability to Pb2+ and is additionally used as the substrate for the in situ growth of lead halogen perovskite. The fluorescence sensing of Pb2+ could be realized by the fluorescence intensity of lead halogen perovskite on the Al(OH)3 layer. The linear relationship between the fluorescence intensity and the concentration of Pb2+ was found in the range from 80 to 1500 mg/kg. The detection limit of Pb2+ is found to be 40 mg/kg, which is lower than the maximum permission of lead residue in student products (90 mg/kg) stipulated by the National Standard of the People's Republic of China (GB21027-2020). After being grinded and pre-treated, soluble lead in watercolor paint and crayon samples can be extracted by the sulfhydryl functionalization Al(OH)3 layer, then lead halogen perovskite can be generated in situ on the layer to achieve the fluorescence sensing for the determination of soluble lead in the samples.