Recovery Of Pb Research Articles

Determining the Structural Properties and Vibrational Modes of Annealed Lead Composite Material Deposit

Techniques for effectively harnessing lead (Pb) deposits for optimum utilization have attracted a lot of research interest. Results obtained from investigating the elemental composition, vibrational modes, and structural properties of a fired Pb composite deposit, which is purified using an electric kiln furnace and further annealed in palladium‐diffused hydrogen ambient, are reported in the present study. Both atomic force microscopy and scanning electron microscopy analysis on the deposit indicate that the Pb composite is composed of crystal‐like morphology. The vibrational modes obtained from the material are identical to the Raman spectrum reported for PbSO4. Also, data acquired from the energy‐dispersive X‐ray analysis of the annealed Pb composite material confirm the presence of zinc, carbon, silicon, sulfur, and oxygen in the material. At the same time, Pb appears to be the primary constituent with reference to its weight percentage composition compared to other elements. The findings from the present study may be vital for providing an improved understanding of the electronic and structural properties of the annealed Pb composite deposit while promoting the development of a feasible approach for the recovery and recycling of Pb for future related applications.

Highly dispersed Ir/Fe nanoparticles anchored at nitrogen-doped activated pyrolytic carbon black as a high-performance OER catalyst for lead recovery.

The use of a methanesulfonic acid (MSA) electrolytic system is recommended as a green method for hydrometallurgical recovery of metallic Pb from waste lead-acid batteries (LABs), contributing to the sustainable protection of the ecosystem. Nevertheless, the system's high energy consumption is a current issue due to the substantial overpotential of the oxygen evolution reaction (OER) and competitive anodic oxidation of Pb2+. Herein, we propose an IrFe/nitrogen-doped pyrolytic carbon black (IrFe/NCBp) composite as a novel OER catalyst for the MSA electrolytic system, which demonstrates advanced OER catalytic efficiency and selectivity for H2O oxidation. This can be ascribed to the catalyst's thoughtful design, which enhances the number and uniformity of Ir and Fe species via increasing the specific surface area and employing NCBp as a sustainable substrate. The optimized IrFe/NCBp composite exhibits superior OER performance, with a low 252 mV@10 mA cm-2 overpotential and a 62 mV dec-1 Tafel slope, and excellent durability in a 1 M MSA electrolyte for 30 h operation compared to commercial Ir/C. In contrast to carbon paper (CP) and commercial Ir/C anodes, the anodic reaction of IrFe/NCBp is primarily OER-driven (97%) in 1 M MSA and 0.2 M Pb2+ electrolyte for Pb recovery. This effectively circumvents the high potential oxidation of Pb2+ into PbO2, reducing the electrolytic voltage to 488 kWh for the recovery of 1 ton Pb metal. This work provides a green, low-carbon footprint solution for the MSA electrolytic system, thereby promoting the commercialization of the hydrometallurgical Pb recovery.

Comparative Screening Study on the Adsorption of Aqueous Pb(II) Using Different Metabolically Inhibited Bacterial Cultures from Industry

The global concern about the water pollution caused by heavy metals necessitates effective water treatment methods. Adsorption, with its substantial advantages, stands out as a promising approach. This study delves into the efficiency of Pb(II) removal using metabolically inhibited microbial cultures. These cultures encompass waste-activated sewage sludge (SS), industrially sourced bioremediation microbes (commercial 1—C1 and commercial 2—C2), an industrially acquired Pb(II) remediating consortium (Cons), and refined strains (derived from Cons) of Paraclostridium bifermentans (PB) and Klebsiella pneumoniae (KP). Our findings reveal maximum Pb(II) adsorption capacities of 141.2 mg/g (SS), 208.5 mg/g (C1), 193.8 mg/g (C2), 220.4 mg/g (Cons), 153.2 mg/g (PB), and 217.7 mg/g (KP). The adsorption kinetics adhere to a two-phase pseudo-first-order model, indicative of distinct fast and slow adsorption rates. Equilibrium isotherms align well with the two-surface Langmuir model, implying varied adsorption sites with differing energies. The Crank mass transfer model highlights external mass transfer as the primary mechanism for Pb(II) removal. Surface interactions between sulfur (S) and lead (Pb) point to the formation of robust surface complexes. FTIR analysis detects diverse functional groups on the adsorbents’ surfaces, while BET analyses reveal non-porous agglomerates with a minimal internal surface area. The Pb(II) recovery rates are notable, with values of 72.4% (SS), 68.6% (C1), 69.7% (C2), 69.6% (Cons), 61.0% (PB), and 72.4% (KP), underscoring the potential of these cost-effective adsorbents for treating Pb(II)-contaminated aqueous streams and contributing to enhanced pollution control measures. Nevertheless, optimization studies are imperative to evaluate the optimal operational conditions and extend the application to adsorb diverse environmental contaminants.

Carbon Paste Electrode Modified by Dibenzo 18-crown-6 for the Determination of Pb in Carrot Using Differential Pulse Voltammetry

In this research, the modification of carbon paste electrode (CPE) using dibenzo 18-crown-6 was carried out to detect Pb level in carrot. The purpose of this electrode modification is to increase the sensitivity of the measurement. The optimized parameters were scan rate, composition of dibenzo 18-crown-6 in carbon paste, and supporting electrolyte. Measurements were validated by determining the linear concentration range, detection limit (LoD), quantification limit (LoQ), repeatability, selectivity, and recovery. At the best measurement conditions, the modified CPE (CPE-Dbc) was applied to determine Pb in carrot. The optimum measurements conditions were obtained the optimum concentration of crown ether in carbon paste was 0.8%, the scan rate using CPE at 15 mV/s, increased to 20 mV/s, and H2SO4 solution as supporting electrolyte. The linear concentration was found in the range of 5-100 µg/L using CPE and became wider to 5-2000 µg/L using CPE-Dbc. The values of LoD and LoQ measurement using CPE were 0,3575 µg/L and 0,3583 µg/L, and decreased to 0,1265 µg/L and 0,1266 µg/L using CPE-Dbc. CPE and CPE-Dbc had good precision with Horwitz ratio values were 0,2231 and 0,2183, which is smaller than two. The percentage of recovery of Pb in the mixture of standard and sample solutions was (88,97 ± 2,76)%. The presence of Cu, Cd and Na in the solution did not interfere the measurement of Pb. The concentration of Pb in carrot sample was (1,8423 ± 0,0002) mg/kg, which was higher than the acceptable concentration according to SNI No. 7387:2009, which is 0,5 mg/kg.

Evaluation of the effect of physical and chemical factors in the recovery of Cu, Pb and Fe from waste PCB through acid leaching

Electronic waste recycling is a strategy that contributes to implement a circular economy model which include reuse, component and raw material recovery and minimum final deposition. Given the importance of reincorporating the components of electronic devices into the productive chain and a correct recovery for some hazardous metals such as lead contained in such residues. This study is focused on the effect of maximum available content (MAC) of metal, sulfuric acid initial concentration, agitation velocity, and oxidising agent on the recovery of copper, lead and iron from electronic waste through acid leaching. A solid-state characterization before and after treatment and electrochemical analysis was carried out to analyse MCA effects and surface chemistry. It was found that sub-millimetric particles show a better available extraction percentage in case of copper and iron, being opposite for lead. Presence of hydrogen peroxide enhance the extraction efficiency, however, this cause iron and lead precipitation, therefore it is inefficient for metals recovery as well as for reagent consumption. The presence of calcium salts reacts producing gypsum, which reduces the extraction yield of copper at particle size below 250 μm.

Recovery of lead and chlorine via thermal co-treatment of municipal solid waste incineration fly ash and lead-rich waste cathode-ray tubes: Analysis of chlorination volatilization mechanism

In this study, a new lead (Pb) and chlorine (Cl) recovery process via the thermal co-treatment of Municipal solid waste (MSW) incineration fly ash (FA) and waste cathode-ray tubes (CRT) was developed and the synergistic effects under different CRT ratios, temperatures, and residence times were comprehensively investigated. Thermogravimetric experiments revealed that the co-processing of FA and CRT exhibited a remarkable synergistic effect as evidenced by the considerable increase in mass loss and mass-loss rate when compared with the theoretical values. When the mixtures with 50% CRT addition was treated at 1200 °C for 60 min, Pb removal rate reached the maximum value of 98.67%, and the Cl removal rate considerably increased by 37.32% compared to that with FA treatment alone. Additionally, the Cl content in the residue was < 2%. It was mainly attributed to the volatilization of chlorides, such as PbCl2, NaCl, and KCl. CaCl2 generated from the decomposition of CaClOH in FA was conducive to improve Pb removal in CRT through indirect chlorination and destroying the glass structure in CRT. Co-processing of FA and CRT demonstrates promising potential for several benefits, including the reduction in melting temperature, recovery of Pb and Cl from secondary fly ash, and the reutilization of calcium-rich slag.

Separation and preparation of level I standard lead concentrate from lead ore via S-HGMS technology: description of separation mechanism

ABSTRACT To eliminate the adverse effects of traditional lead ore flotation methods, such as high reagent cost, complex operation process, and a large amount of wastewater, a superconducting high gradient magnetic separation (S-HGMS) technology was proposed to prepare level I standard lead concentrate (IGC) from lead ore. Under optimal conditions including a magnetic flow ratio of 0.076 T·s/m, a pulp concentration of 1.5%, a slurry flow velocity of 500 mL/min, and a 90% mass fraction of minus 45 μm, the Pb grade of the IGC product increased from 45.36% to 68.79% with 55.43% of Pb recovery, while all Cu, Zn, As, Fe, MgO, and Al2O3 concentrations of IGC decreased. The obtained IGC product meets the standard of level I in YS/T319–2013. The characterization results showed that lead ore comprised galena, sphalerite, and chalcopyrite. After S-HGMS, galena was effectively concentrated in the IGC product, while sphalerite and chalcopyrite were separated into the tailings. The magnetic field intensity and mineral magnetization characteristics were vital factors affecting the Pb grade and recovery of the IGC product. The S-HGMS technology efficiently achieved the preparation of the IGC product from lead ore, without using flotation agents and generating wastewater, and provides a valuable guideline for separating Cu – Pb, Zn – Pb, and Cu – Zn – Pb minerals.

A novel method has been developed to efficiently recover valuable lead, zinc, and rare earth elements from hazardous waste generated by glass polishing

Discovering new processing routes to put waste to use in the manufacturing of high-value products is essential to the success of the circular economy. A glass polishing waste containing 16.4% PbO, 0.672% ZnO and 7.296% rare earth elements (REEs) oxides was subjected to this work. The current research looked into the feasibility of adopting a sequential three-stage leaching procedure to selectively recover Pb, Zn, and REEs from hazardous glass polishing waste (HGPW). First-stage leaching with 1 M H2SO4 at 80 °C for 90 min extracted 75–99.9% of contaminant heavy metals such Fe, Ni, Co, and Cu, leaving behind insoluble residue containing the metals of interest. In the second stage of leaching, the sodium hydroxide solution extracted Pb and Zn from the first spend residue. Using shrinking core models, we were able to assess the kinetics of lead and zinc dissolution. The activation energy was determined to be 32.16 kJ/mol for Pb and 34.59 kJ/mol for Zn. In the final step, the REEs were extracted from the dried alkali-treated residue by leaching it with concentrated H2SO4 at higher temperatures. For the technological recovery of Pb, Zn, and REEs from glass polishing waste, a flow chart was created.

Feasibility and reaction process for recovery of Si and Pb from high‐calcium zinc extraction residue by alkali roasting

AbstractTo explore the feasibility of Si and Pb recovery from high‐calcium zinc extraction residues via alkali roasting, NaOH molten roasting is performed and the reaction process is discussed. Under the optimal reaction conditions—residue–alkali ratio of 1:5.0, reaction time of 1.75 h, and reaction temperature of 500°C—the Si and Pb extraction ratios remained stable at 74.00% and 40.00%, respectively. The X‐ray diffraction patterns of the specimens roasted at different temperatures indicated that the main factor affecting the extraction process was the presence of Na2CaSiO4, Ca2PbO4, and quartz. Further, the phase transformations and reaction processes of Si and Pb were determined. In the final phases, the specimen roasted at 550°C included quartz, Na4SiO4, Na2CaSiO4, Ca2PbO4, and Na2SO4. The kinetics data calculated using the unreacted shrinking core model showed that the roasting process followed a mixed control mechanism with an apparent activation energy of 16.99 kJ · mol−1.

Amino-functionalised chrysin as adsorbent in dispersive micro-solid phase extraction of selected heavy metal ions from stingless bee honey

The study includes the preparation, characterisation, and application of a new adsorbent, 3-aminopropyltriethoxysilane modified chrysin (CHY-APTES), to extract Pb(II), Cr(III), and Cd(II) from stingless bee honey samples using dispersive micro-solid phase extraction (d-µ-SPE) and detected by graphite furnace atomic absorption spectrometer. Characterisation techniques of CHY-APTES including Brunauer-Emmett-Teller surface area analysis, Fourier transform infrared spectroscopy, scanning electron microscopy-energy dispersive x-ray imaging and point of zero charge determination. Several parameters were studied and optimised, such as a desorption time of 15 min, an adsorption time of 3 min, the use of nitric acid solution as the desorption solvent, 120 mg of adsorbent mass, solution pH adjusted to pH 5, and ethanol employed as the dispersive solvent. The results demonstrated good relative recoveries for Pb(II), Cr(III) and Cd(II) in the range of 74.76–116.34 %, 83.59–115.83 % and 89.03–117.66 %, respectively, with good precision at a relative standard deviation≤11.46%. For method sensitivity, the method showed acceptable detection limits (3 S/N) for Pb(II), Cr(III) and Cd(II) extracted from stingless bee honey samples at 43.6, 348.9 and 56.7 µg/kg, respectively. The preconcentration factors calculated for Pb(II), Cr(III), and Cd(II) were 111, 9.5, and 49, respectively. The newly developed CHY-APTES was successfully applied in d-µ-SPE for the first time. It was adequate in terms of analytical performance and simple in preparing stingless bee honey samples via dilution.

Rapid and sensitive determination of Se and heavy metals in foods using electrothermal vaporization inductively coupled plasma mass spectrometry with a novel transportation system.

Rapid, sensitive and simultaneous determination of trace multi-elements in various plant food samples such as grain, oilseed, vegetable and tea is always a challenge thus far. In this work, a rapid determination method for Se, Cd, As and Pb in food samples by inductively coupled plasma mass spectrometry (ICP-MS) using slurry sampling electrothermal vaporization (SS-ETV) was developed. To improve the analytical sensitivity and precision as well as eliminate the memory effect, a gas turbulator line and signal delay device (SDD) were for the first time designed for the graphite furnace (GF) ETV coupled with ICP-MS. The signal acquisition parameters of ICP-MS, ashing and vaporization conditions, and the flow rates of carrier gas and gas turbulator were investigated for Se, Cd, As and Pb in food samples. Under the optimized conditions, the limits of determination (LODs) for Se, Cd, As and Pb were 0.5 ng g-1, 0.3 ng g-1, 0.3 ng g-1 and 0.6 ng g-1, respectively; the limits of quantification (LOQs) for Se, Cd, As and Pb were 1.7 ng g-1, 1.0 ng g-1, 1.0 ng g-1 and 1.9 ng g-1, respectively; linearity (R2) in the range of 1 to 4,000 ng g-1 was >0.999 using the standard addition method. This method was used to analyze 5 CRMs including rice, tea and soybeans, and the concentrations detected by this method were within the range of the certified values. The recoveries of Se, Cd, As and Pb in plant food matrices including grain, oilseed, celery, spinach, carrot and tea samples were 86-118% compared to the microwave digestion ICP-MS method; and the relative standard deviations (RSDs) were 1.2-8.9% for real food sample analysis, proving a good precision and accuracy for the simultaneous determination of multi-elements. The analysis time was less than 3 min, slurry preparation time < 5 min without sample digestion process. The proposed direct slurry sampling ICP-MS method is thus suitable for rapid and sensitive determination of Se, Cd, As and Pb in food samples with advantages such as simplicity, green and safety, as well as with a promising application potential in detecting more elements to protect food safety and human health.

Valorisation of spent tire rubber as carbon adsorbents for Pb(II) and W(VI) in the framework of a Circular Economy

Spent tire rubber-derived chars and their corresponding H3PO4 and CO2-activated chars were used as adsorbents in the recovery of Pb(II) ion and (W(VI)) oxyanion from synthetic solutions. The developed chars (both raw and activated) were thoroughly characterized to have insight about their textural and surface chemistry properties. H3PO4-activated chars presented lower surface areas than the raw chars and an acidic surface chemistry which affected the performance of these samples as they showed the lowest removals of the metallic ions. On the other hand, CO2-activated chars presented increased surface areas and increased mineral content compared to the raw chars, having presented higher uptake capacities for both Pb(II) (103–116 mg/g) and W(VI) (27–31 mg/g) ions. Cation exchange with Ca, Mg and Zn ions was appointed as a mechanism for Pb removal, as well as surface precipitation in the form of hydrocerussite (Pb3(CO3)2(OH)2). W(VI) adsorption might have been ruled by strong electrostatic attractions between the negatively charged tungstate species and the highly positively charged carbons’ surface.The results shown in this work allow concluding that the valorisation of spent tire rubber through pyrolysis and the subsequent activation of the obtained chars is an alternative and a feasible option to generate adsorbent materials with a high uptake capacity of critical metallic elements.

Statistical Optimization of Bioleaching for Simultaneous Recovery of Cu, Sn, Pb, and Zn from Computer-Printed Circuit Boards

Electronic garbage is one of the fastest-growing waste streams. Its disposal and appropriate management are a worldwide concern. Printed circuit boards (PCBs) are critical components in contemporary electronic gadgets that contain toxic elements. Bioprocessing of PCBs for metal recovery employing microbial methods has evolved as a green solution in metallurgical operations. Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans were used in this study to leach metals from powdered waste PCBs. The RSM is used for optimizing the leaching conditions. The optimal conditions obtained were a bacterial activation period of 28 days, a pulp density of 23 g/L, and a temperature of 31°C. A confirmatory experiment under these optimal circumstances yielded recovery rates of Cu2+, Sn2+, Pb2+, and Zn2+ of 95.62%, 96.27%, 95.6%, and 98.25%, respectively.

Geoenvironmental characterisation of legacy mine wastes from Tasmania – Environmental risks and opportunities for remediation and value recovery

A detailed characterisation of potential environmental risks is required to implement adequate mine waste management strategies at abandoned mine sites. This study assessed the long-term potential of six legacy mine wastes from Tasmania to generate acid and metalliferous drainage (AMD). Mineralogical analyses by X-ray diffraction (XRD) and mineral liberation analysis (MLA) revealed the mine wastes were oxidised onsite and contained up to 69% of pyrite, chalcopyrite, sphalerite, and galena. Oxidation of the sulfides under laboratory static and kinetic leach tests generated leachates with pH 1.9–6.5, suggesting long-term acid-forming potentials. The leachates contained some potentially toxic elements (PTE)s including Al, As, Cd, Cr, Cu, Pb, and Zn in concentrations exceeding the Australian freshwater guidelines by up to 105 times. The indices of contamination (IC) and toxicity factors (TF)s of the PTEs ranked between very low and very high relative to soils, sediments, and freshwater guidelines. The outcomes of this study highlighted the need for AMD remediation at the historical mine sites. Passive addition of alkalinity is the most practical remediation measure for these sites. They may also be opportunities for the recovery of quartz, pyrite, Cu, Pb, Mn, and Zn from some of the mine wastes.

Greener synthesis of novel nanocomposite material for efficient and selective trace detection of Pb&lt;sup&gt;2+&lt;/sup&gt;: Insights of stability and real implications of fabricated electrode

This work reports the use of highly efficient nanocomposite material fabricated glassy carbon electrode (Ag(NPs)/ChS/GC) in the trace detection of Pb&lt;sup&gt;2+&lt;/sup&gt; using differential pulse voltammetry (DPV). A facile method yielded the silane-grafted chitosan (ChS) using 3-trimethoxyoctylsilane, and the bioderived Ag(NPs) was &lt;i&gt;in situ&lt;/i&gt; decorated on the ChS composite to obtain Ag(NPs)/ChS. X-ray Diffraction (XRD) results showed the presence of Ag(NPs) within the composite material. Spherical-shaped and uniform distribution of Ag(NPs) were observed in SEM and TEM images of the nanocomposite solid. The cyclic voltammetric studies revealed a significant increase in redox peak currents (i.e., 0.1283 mA), which was obtained using the Ag(NP)/ChS/GC compared to the bare glassy carbon electrode. Further, the electrochemical determination of Pb&lt;sup&gt;2+&lt;/sup&gt; showed good linearity in anodic peak current and Pb&lt;sup&gt;2+&lt;/sup&gt; concentrations (5.0-80.0 &lt;i&gt;μ&lt;/i&gt;g/L), and the limit of detection was 1.97 &lt;i&gt;μ&lt;/i&gt;g/L. With 10-fold increase in several cationic and anionic interfering ions, oxalic acid and glycine only show interference in determination of Pb&lt;sup&gt;2+&lt;/sup&gt;. The reproducibility study showed a %RSD of 2.43%, and the electrode could be efficiently used for prolonged and repetitive detection having reasonably low %RSD of 2.55%. The real water analysis showed almost 100% recovery of Pb&lt;sup&gt;2+&lt;/sup&gt; in two different real water samples.

An offline column extraction with Presep® PolyChelate resin and AG1‐X8 resin for the determination of the isotope compositions of low‐concentration lead in natural waters by the multi‐collector inductively coupled plasma mass spectrometry

AbstractA new high‐precision offline method for the determination of seawater lead (Pb) isotope ratios was developed, which simplifies and optimizes previously published protocols for the isotopic analysis of trace elements. The procedure involves initial separation of Pb from 250 to 500 mL of seawater by Presep® PolyChelate cation exchange resin and purification by AG1‐X8 anion exchange resin, and subsequently analyzed by Neptune multi‐collector ICP‐MS. For the extraction of Pb in seawater, the Presep® PolyChelate resin was characterized by a wide pH range and a faster adsorption rate, greatly reducing the volume of buffer solution required and significantly shortening the time required for the whole process. The total procedural Pb blank of this method is &lt; 0.05% of the sample extract and the typical Pb recovery is ~ 100%. The method was evaluated by processing GEOTRACES intercalibration samples surface water (GSI, 206Pb/207Pb = 1.1744, 208Pb/206Pb = 2.0844) and GEOTRACES GP15 sample (14140#, 206Pb/207Pb = 1.1685, 208Pb/206Pb = 2.0960). Finally, this method was applied to riverine samples from the Changjiang and seawater samples from the East China Sea, and the in situ extraction was also applied in the Indian Ocean.

Bioremediation of Wastewater Using Yeast Strains: An Assessment of Contaminant Removal Efficiency.

The main goal of wastewater treatment is to significantly reduce organic compounds, micronutrients (nitrogen and phosphorus) and heavy metals and other contaminants (pathogens, pharmaceuticals and industrial chemicals). In this work, the efficiency of removing different contaminants (COD, NO3-, NO2-, NH4+, PO43-, SO42-, Pb2+, Cd2+) from synthetic wastewater was tested using five different yeast strains: Kluyveromyces marxianus CMGBP16 (P1), Saccharomyces cerevisiae S228C (P2), Saccharomyces cerevisiae CM6B70 (P3), Saccharomyces cerevisiae CMGB234 (P4) and Pichia anomala CMGB88 (P5). The results showed a removal efficiency of up to 70% of COD, 97% of nitrate, 80% of nitrite, 93% of phosphate and 70% of sulfate ions for synthetic wastewater contaminated with Pb2+ (43 mg/L) and Cd2+ ions (39 mg/L). In contrast, the results showed an increase in ammonium ions, especially in the presence of Pb2+ ions. The yeast strains showed a high capacity to reduce Pb2+ (up to 96%) and Cd2+ (up to 40%) ions compared to the initial concentrations. In presence of a crude biosurfactant, the removal efficiency increased up to 99% for Pb2+ and 56% for Cd2+ simultaneously with an increase in yeast biomass of up to 11 times. The results, which were obtained in the absence of aeration and in neutral pH conditions, proved a high potential for practical applications in the biotreatment of the wastewater and the recovery of Pb and Cd ions, with a high benefit-cost ratio.

Grade and Tonnage Comparison of Anthropogenic Raw Materials and Ores for Cu, Zn, and Pb Recovery

Primary metal production operates with large tonnages and takes advantage of economies of scale. Metal recycled from low-value waste streams, competing in the same global metal market as primary production, will be more competitive by also taking advantage of up-scaling. However, an overview of metal tonnages in low-value waste streams to see upscaling potential needs to be provided in the literature. In response, this study provides estimates of copper, zinc, and lead metal tonnages in waste incineration ash—A major waste stream going to landfills. Metal concentrations and tonnages are compared to tonnages and concentration grades found in ores. Copper, zinc, and lead concentration averages are about 3–5 times lower in ash compared to the worldwide average head grade of ores. Tonnages of metal in the ash generated from waste incineration in European countries bordering the Baltic and the North Sea are about 1/3 of mining metal output from Sweden, a leading mining country in the region. Therefore, incineration ash should be considered a significant potential Cu, Zn, and Pb metal source.

Genetic algorithm-assisted artificial neural network modelling for remediation and recovery of Pb (II) and Cr(VI) by manganese and cobalt spinel ferrite super nanoadsorbent

MnFe2O4 and CoFe2O4 nanoparticles were hydrothermally synthesized to examine their capability in adsorption of Pb (II) and Cr (VI). The adsorbents exhibited a high rate of adsorption, reaching 90% of their adsorption capacity in less than 30 min. Furthermore, the adsorption capability of the Magnetic Nanoparticles (MNPs) was noticeably greater at initial pollutant concentrations smaller than 40 mg/L. Maximum adsorption capacity on MnFe2O4 and CoFe2O4 nanoparticles were 40 and 25.38 mg/g for Cr (VI) and 523.32 and 476.19 mg/g for Pb (II), respectively. A data-driven model of Artificial Neural Network was used for prediction of adsorption capacity at both equilibrium and non-equilibrium condition. The model parameters including the numbers of neuron (n = 7) and data portioning for training (49.5%), validation (40.5%), and testing (10%) were obtained using Genetic Algorithm. The results indicated that the model could predict the data with high accuracy (R2 = 0.998). The input parameters were initial concentration, time, pH, temperature, adsorbent dosage, and other parameters that is dependent to the physico-chemical properties of ions and adsorbents’ surface (ε, α1, α2). The mechanism involved in Cr(VI) and Pb(II) adsorption are electrostatic physisorption and a combination of ion exchange chemisorption and electrostatic physisorption, respectively. Desorption capability and adsorbent reuse capability were also examined.

Methylthiazole Schiff base functionalized SBA-15 for high-performance Pb(Ⅱ) capture and separation

Selective recovery of Pb(II) from effluent reduces its toxic impact on environment and benefits for saving non-renewable lead resources. To capture and separate Pb(II), a kind of methylthiazole Schiff base modified mesoporous silica, denoted as MTCI-SBA-15, was fabricated via grafting amino groups onto SBA-15 which was followed by Schiff condensation with 4-methylthiazole-5-carboxaldehyde. A variety of characteristic methods monitored the evolution of the modified adsorbent. Pb(II) uptake to MTCI-SBA-15 was studied in batch mode concerning pH, contact time, initial concentration, temperature, coexisting metallic ions, etc. Kinetic analyses revealed that the pseudo-second-order model was suitable for describing adsorption process. The adsorption isotherms were well represented by the Langmuir model. The thermodynamic study confirmed that the sorption was spontaneous and endothermic. The maximal load ability of MTCI-SBA-15 (283 mg g−1) for Pb(II) outperformed that of most modified mesoporous silica adsorbents. Moreover, Pb(II) removal efficiency higher than 99% can be reached with a low initial concentration (<50 mg L−1). Testing on the effects of competing ions suggested that MTCI-SBA-15 exhibited a desirable selectivity for Pb(II). Further, MTCI-SBA-15 was recyclable, retaining 93.1% of the adsorption capacity after five successive cycles. Mechanisms investigation indicated that the imine N atom on the Schiff base and the S atom on the 4-methylthiazole ring played a synergistic role during the adsorption process for Pb(II). The MTCI-SBA-15 showed excellent application potential for Pb(II) capture and separation.