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Microbial extracellular polymeric substances (EPS) have recently emerged as significant contributors in diverse biotechnological applications. Extracellular polymeric substances (EPS), produced by a Navicula salinicola strain, have been studied for potential applications in a specific heavy metal (lead (Pb II)) removal from wastewater. The optimisation of operational parameters, mainly pH, Pb and EPS concentrations, using the Box–Behnken design (BBD) was undertaken to enhance lead uptake. The higher Pb adsorption capacity reached 2211.029 mg/g. Hydroxyl, carbonyl, carboxyl, phosphoric, and sulfhydryl groups were identified quantitatively as potential sites for Pb adsorption. EPS exhibited a notable flocculation rate of 70.20% in kaolin clay at a concentration of 15 mg/L. They demonstrated an emulsifying activity greater than 88%, showcasing their versatile potential for both sedimentation processes and stabilising liquid–liquid systems. EPS could be excellent nonconventional renewable biopolymers for treating water and wastewater. [ABSTRACT FROM AUTHOR]

Removal of heavy metals becomes increasingly crucial for public health and the environment. In this regard, Bi2S3 nanoflowers were produced for heavy metal ion removal applications. Nanoflowers are fabricated using hydrothermal synthesis, and then tested as adsorbents for the removal of lead (Pb2+) ions from aqueous systems. To assess the morphological and chemical characteristics, Bi2S3 nanoflowers were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) techniques. Flame atomic adsorption spectroscopy (FAAS) was used in the assessment of heavy metal ion recovery. To determine the optimum conditions of the adsorption system, the effect of different parameters such as pH, eluent type and amount, adsorbent dose, adsorbent time, etc. were investigated. For lead removal, the optimum pH value was determined as 5.0, eluent dose and type were found 1 M HNO3. For 20 mL, the optimum adsorbent dose and time were found 50.0 mg, and 30 min, respectively. The adsorption capacity of the Bi2S3 nanoflowers was found to be quite higher than the results reported in similar works. It was illustrated that Bi2S3 nanoflowers have great potential to be used in water remediation applications as sorbent material. [ABSTRACT FROM AUTHOR]

Water contamination currently threatens human health, which is still a major environmental issue. Scientists are paying attention, in particular, to lead poisoning of water caused by industrial wastes on a global scale. In order to reduce agricultural waste and promote sustainable development, this study created a straightforward process for using leftover rice husks to create biochar. At first, the rice husk biochar was prepared; then, following the immersion of biochar with precursors of Fe2+ and Fe3+ and precipitation under alkaline condition, the Fe3O4 was formed and laid onto biochar to create another magnetic adsorbent known as ferrous-modified biochar. The success of loading Fe3O4 was confirmed by SEM, XRD, FTIR, and BET measurements. The delivered ferrous-modified biochar has a high surface area and correct functional groups for the adsorption process. In order to remove Pb (II) from wastewater, rice husk biochar and ferrous-modified biochar materials were used. Under optimized conditions, synthesized ferrous-modified biochar has a lead adsorbent effectiveness of 95.0% that is related to varying pathways as co-precipitation reaction, complexation reaction, conjugation adsorption, ion exchange, and Fe–O coordination. The Pb2+ adsorption capacity of modified biochar is three times greater than rice husk biochar with 73.68 mg/g. Another evidence of the ferrous-modified biochar adsorbent's excellent recyclable properties is the remaining lead efficiency, which was over 41.2% even after six recycling cycles. Therefore, by this approach of synthesizing Fe3O4 loaded on biochar, the research provided new opportunities for developing low-cost and highly efficient adsorbent to remove heavy metals from water. [ABSTRACT FROM AUTHOR]

Mining, particularly gold mining, is a lucrative industry. However, it poses significant environmental risks, such as releasing heavy metal elements into the soil and water. After gold mines are exhausted, whether they are small or large scale, the excavated sites often need to be repaired. This situation has led to a global concern regarding the presence of heavy metals from mining activities, which are known to be carcinogenic and harmful to living organisms. The concentration of heavy metals in these areas often surpasses safety limits, necessitating advanced treatment methods for their removal, especially lead (Pb) compounds from gold mining waste. One effective treatment method is the adsorption process. This study examined POFA's inherent capacity to remove lead from water contaminated by gold mining without modification. This method was preferred due to its high efficiency and cost-effective option for removing heavy metal compounds. According to the experiment's results, the largest adsorption capacity of 0.816 mg/g was followed by the greatest removal efficiency of 91.837%. The isotherm analysis found that the Langmuir model provided an outstanding fit for the experimental data. Thus, this relationship suggested that on the surface of the POFA, a monolayer and an adsorption process suitable for physical adsorption took place.

Introduction: Transvenous lead extraction (TLE) is generally considered a safe procedure, albeit not without risks. While gender‐based disparities have been noted in short‐term outcomes following TLE, a notable gap exists in understanding the long‐term consequences of this procedure. The objective of this analysis was to investigate sex differences in both acute and long‐term outcomes among patients who underwent TLE at a tertiary referral center. Methods: In this retrospective cohort study, consecutive patients who underwent TLE between January 2014 and January 2016 were enrolled. The primary outcome comprised a composite of all‐cause mortality and need for repeated TLE procedures. Secondary outcomes included fluoroscopy time, lead extraction techniques, success rates, and major and minor complications. Results were compared between female and male cohorts. Results: The study population comprised 191 patients (median age, 70 years), 29 (15.2%) being women and 162 men (84.8%). Study groups had similar baseline characteristics. Complete procedural success was achieved in 189 out of 191 patients (99.0%), with no significant difference observed between the two groups (p =.17). No major complications were reported in the total cohort. However, there was a significantly higher incidence of minor complications in women compared to men (17.2% vs. 2.5%, p <.01). Following a median follow‐up of 6.5 years, the incidence of the primary composite outcome occurred similarly between the study groups (log‐rank p =.68). Conclusion: Women who underwent TLE exhibited a significantly higher incidence of minor acute intra‐ and peri‐procedural complications than men. However, no differences in long‐term outcomes between genders were observed. [ABSTRACT FROM AUTHOR]

Mining, particularly gold mining, is a lucrative industry. However, it poses significant environmental risks, such as releasing heavy metal elements into the soil and water. After gold mines are exhausted, whether they are small or large scale, the excavated sites often need to be repaired. This situation has led to a global concern regarding the presence of heavy metals from mining activities, which are known to be carcinogenic and harmful to living organisms. The concentration of heavy metals in these areas often surpasses safety limits, necessitating advanced treatment methods for their removal, especially lead (Pb) compounds from gold mining-impacted water. One effective treatment method is the adsorption process. This study examined POFA's inherent capacity to remove lead from water contaminated by gold mining without modification. This method was preferred due to its high efficiency and cost-effective option for removing heavy metal compounds. According to the experiment's results, the largest adsorption capacity of 0.816 mg/g was followed by the greatest removal efficiency of 91.837%. The isotherm analysis found that the Langmuir model provided an outstanding fit for the experimental data. Thus, this relationship suggested that on the surface of the POFA, a monolayer and an adsorption process suitable for physical adsorption took place. [ABSTRACT FROM AUTHOR]

Lead (Pb(II)) ions in water pose a significant threat to both human health and aquatic ecosystems. Various approaches have been employed for wastewater treatment, but adsorption is often preferred due to its effectiveness. However, its practical application is limited by the large quantities of adsorbent required, which consequently increases operational costs. In this study, orange-modified iron-oxide nanoparticles (O-Fe3O4) are synthesized from agro-waste mass (orange peel), and adsorption experiments were conducted for the removal of Pb(II) from aqueous solution. Characterization studies confirm that O-Fe3O4 nanoparticles possess a mesoporous hexagonal nanocrystalline structure, with diameters measuring less than 100 nm. The adsorption process was optimized using a central composite design framework combined with response surface methodology. The analysis of interaction effects demonstrated that they significantly influenced the effectiveness of adsorption removal. The study revealed that an initial concentration of 25 mg/L, a dosage of 0.2 g/L, a contact period of 90 min, and a pH of 5.5 were the optimum conditions to achieve above 95% of Pb(II) removal. The green synthesized O-Fe3O4 nanoparticles, which presented high efficacy, makes it a promising option for implementing the sustainable water purification. [ABSTRACT FROM AUTHOR]

Aims The extravascular implantable cardioverter-defibrillator (EV ICD) has been shown to be safe and effective for patients at risk of sudden cardiac death, but little is known about EV ICD lead removal in humans. This analysis aimed to characterize the EV ICD lead removal experience thus far. Methods and results This was a retrospective analysis of lead removals from the EV ICD Pilot, Pivotal, and Continued Access Studies. Patients with a successful EV ICD implant who underwent lead removal were included. The main objective was lead removal success. Ancillary objectives included characterizing technique used, procedure complications, and reimplantation status. An EV ICD system was successfully implanted in 347 patients across the 3 studies (25.9% female; 53.4 ± 13.3 years; left ventricular ejection fraction: 39.7 ± 15.9). Of these patients, 29 (8.4%) underwent lead removal with a mean lead dwell time of 12.6 ± 14.3 months (0.2–58.4). The main reason for lead removal was lead dislodgement (n = 9, 31.0%). Lead removal was successful in 27/29 (93.1%) cases [100% (19/19) success rate <1 year and 80% (8/10) success rate >1 year post-implant]. Simple traction was used in 22/26 (84.6%) and extraction tools in 4/26 (15.4%) successful cases where technique was known. No complications were reported for any of the removal procedures. All 11 EV ICD reimplant attempts were successful. Conclusion Complete removal of the EV ICD lead was successful in 93.1% of cases, and simple traction was sufficient in most instances. Based on these results, lead removal from the substernal space was safe and achievable up to 3 years post-implant. [ABSTRACT FROM AUTHOR]

Abstract Lead (Pb) contamination in water poses a significant threat to public health across the globe which requires effective remediation strategies. The main objective of this study is to achieve a removal efficiency of Pb(II) ions from aqueous media using activated Syzygium cumini (java plum) stem biochar. It was prepared by slow pyrolysis at 400 °C after treating the biomass with potassium hydroxide for activation. These biochars were characterized thoroughly (SEM, SEM–EDX, TEM, FTIR, XRD, elemental analyses, and SBET) to conduct a set of batch experiments. The effect of several parameters such as pH, temperature, contact time, adsorbent dosage, initial lead concentrations, and co-existing ions were explored. The decrease in starting lead concentrations from 50 to 10 mg L−1 resulted in improved removal efficiency. The removal effectiveness of activated biochar was 97%, but non-activated biochar was just 19%. Lead adsorption increased considerably as pH increased from 3 to 5. Further, the activated biochar was optimized through various isotherms models, kinetic equations, and thermodynamic analysis. It was observed that the pseudo-second-order kinetic model and Temkin isotherms were the best-fitted models that identify the mechanism of chemisorption and monolayer sorption. According to this study, activated biochar is a promising biosorbent for removing lead from an aqueous solution. Graphical Abstract

Lead (Pb) contamination in water poses a significant threat to public health across the globe which requires effective remediation strategies. The main objective of this study is to achieve a removal efficiency of Pb(II) ions from aqueous media using activated Syzygium cumini (java plum) stem biochar. It was prepared by slow pyrolysis at 400 °C after treating the biomass with potassium hydroxide for activation. These biochars were characterized thoroughly (SEM, SEM–EDX, TEM, FTIR, XRD, elemental analyses, and SBET) to conduct a set of batch experiments. The effect of several parameters such as pH, temperature, contact time, adsorbent dosage, initial lead concentrations, and co-existing ions were explored. The decrease in starting lead concentrations from 50 to 10 mg L−1 resulted in improved removal efficiency. The removal effectiveness of activated biochar was 97%, but non-activated biochar was just 19%. Lead adsorption increased considerably as pH increased from 3 to 5. Further, the activated biochar was optimized through various isotherms models, kinetic equations, and thermodynamic analysis. It was observed that the pseudo-second-order kinetic model and Temkin isotherms were the best-fitted models that identify the mechanism of chemisorption and monolayer sorption. According to this study, activated biochar is a promising biosorbent for removing lead from an aqueous solution. [ABSTRACT FROM AUTHOR]

• Six types of campus fallen leaves were collected to produce biochar at 300 °C. • Adsorption capacity of leaf biochars for Pb vary from 31 to 209 mg/g. • Intraparticle diffusion controlled the adsorption kinetics of Pb onto PB. • 27% of total adsorbed Pb existed as the exchangeable fraction on PB. • Hydrocerussite and cerussite contributed to the great acid soluble Pb on YDB. Realizing campus sustainability requires the environmental-friendly and economical treatment of tremendous fallen leaves. Producing fallen leaf biochar at a low temperature is a candidate approach. In this study, six common types of fallen leaves on the campus were pyrolyzed at 300 °C. The obtained biochars were characterized and the adsorption mechanisms of lead (Pb) by the fallen leaf biochars were investigated. The adsorption capacity of leaf biochar for Pb was relatively high, up to 209 mg/g (Yulania denudata leaf biochar). Adsorption of Pb onto active sites was the rate-limiting step for most leaf biochars. But for Platanus leaf biochar, intraparticle diffusion of Pb2+ dominated owing to the lowest adsorption capacity. However, the highest exchangeable Pb fraction (27%) indicated its potential for removing aqueous Pb2+. Ginkgo and Prunus cerasifera leaf biochar immobilized Pb by surface complexation and precipitation as lead oxalate. Hence, they were suitable for soil heavy metal remediation. This study shed the light on the sustainable utilization of campus fallen leaves and the application of fallen leaf biochars in heavy metal remediation. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, strontium hexaferrite (SrFe 12 O 19) with partial substitutions of aluminum and calcium (Sr 0·67 Ca 0·33 Fe 8 Al 4 O 19) and hexaferrite with partial substitutions of manganese (SrMnFe 11 O 19) were synthesized by the polymeric complex method (Pechini). The samples were calcined at a temperature of 1000 °C for 4 h. The crystalline phases, structure, and morphology of the samples were determined by X-ray diffraction, scanning electron microscope, and transmission electron microscopy. The magnetic properties were measured at room temperature using a vibrating sample magnetometer with an applied field of up to 20 kOe. The point of zero charge was determined by measuring the zeta potential. Finally, for adsorption experiments, the concentration of Pb (II) in the samples was determined by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The results show that the sample with partial manganese substitutions (SrMnFe 11 O 19) exhibits the highest removal of pollutants (Pb2+) with a maximum adsorption capacity of 24.23 mg/g. [ABSTRACT FROM AUTHOR]

Water contamination caused by inconsistencies in the removal of contemporary colors and heavy metals constitutes a serious global ecological concern. This study introduces a composite material made of cellulose acetate coated with activated carbon, which is made more effective by including pectic enzymes. This composite is easily manufactured and has caused considerable interest due to its potential in wastewater treatment via absorption‐based techniques for the photocatalytic degradation of methylene blue dye and lead removal. Thermal processing and electrospinning are used in the synthesis process. Field emission scanning electron microscopy (FE‐SEM), Energy Dispersive Xray‐ Analysis (EDX), Brunauer–Emmett–Teller (BET), and UV‐absorbency were used to characterize the resultant pectic cellulose/activated carbon nanofibers (P‐CNFs). In addition, inductively coupled plasma‐mass spectroscopy (ICP‐MS) was used to evaluate lead ion adsorption. Several parameters, including initial lead ion and methylene blue concentrations, solution pH, and nanofiber, were investigated. Fifty percent of pectic‐containing composite (cellulose/activated carbon) P‐CNF has shown remarkable differences when compared to non‐pectic and different ratio composite due to higher surface area and porosity. It also increases light absorption and decreases charge recombination, resulting in a maximum degradation efficiency of 98.5% in a neutral solution under UV‐light irradiation for 25 min, compared to pure CNF (degradation efficiency is 49% after 60 min of irradiation). In the case of lead removal, 80% efficiency was achieved in 5 min. [ABSTRACT FROM AUTHOR]

The apple processing industry generates large quantities of organic waste, presenting a major source of organic contamination. Consequently, finding an effective solution for valorizing this waste has become a pressing issue. This study aims to address two key concerns: (i) solving an agricultural problem by efficiently using agri-food residue, and (ii) removing lead, an extremely toxic element, from contaminated waters to mitigate environmental pollution. Two biosorbents were tested: raw apple waste (RA), obtained from a mixture of apple varieties, and the same material after extracting valuable bioactive and reusable components, extracted apple (EA). The study evaluated the influence of pH, initial biosorbent mass, adsorption kinetics, and equilibrium isotherms. The results are very promising, showing a lead removal efficiency of 82 % for RA and 100 % for EA at a low initial concentration of the solution of 20 mg Pb2⁺/L and an optimal pH of 5 ± 0.5. The Langmuir model predicted a maximum adsorption capacity of 44.6 mg/g for RA and 48.6 mg/g for EA. These findings demonstrate that apple waste, even after selective extraction of valuable bioactive components, can be effectively used for environmental remediation on a practical scale.

Abstract Due to the characteristics of electrospun nanofibers (NFs), they are considered a suitable substrate for the adsorption and removal of heavy metals. Electrospun nanofibers are prepared based on optimized polycaprolactone (PCL, 12 wt%) and polyacrylic acid (PAA, 1 wt%) polymers loaded with graphene oxide nanoparticles (GO NPs, 1 wt%). The morphological, molecular interactions, crystallinity, thermal, hydrophobicity, and biocompatibility properties of NFs are characterized by spectroscopy (scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Thermogravimetric analysis), contact angle, and MTT tests. Finally, the adsorption efficacy of NFs to remove lead (Pb2+) from water and apple juice samples was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). The average diameter for PCL, PCL/PAA, and PCL/PAA/GO NFs was 137, 500, and 216 nm, respectively. Additionally, the contact angle for PCL, PCL/PAA, and PCL/PAA/GO NFs was obtained at 74.32º, 91.98º, and 94.59º, respectively. The cytotoxicity test has shown non-toxicity for fabricated NFs against the HUVEC endothelial cell line by more than 80% survival during 72 h. Under optimum conditions including pH (= 6), temperature (25 °C), Pb concentration (25 to 50 mg/L), and time (15 to 30 min), the adsorption efficiency was generally between 80 and 97%. The adsorption isotherm model of PCL/PAA/GO NFs in the adsorption of lead metal follows the Langmuir model, and the reaction kinetics follow the pseudo-second-order. PCL/PA/GO NFs have shown adsorption of over 80% in four consecutive cycles. The adsorption efficacy of NFs to remove Pb in apple juice has reached 76%. It is appropriate and useful to use these nanofibers as a high-efficiency adsorbent in water and food systems based on an analysis of their adsorption properties and how well they work.

Bicarbonate ions (HCO3−) are abundant in karst water with poor lead (Pb) utilization and biodegradation. This study aimed to investigate the mechanism of HCO3− on the Pb removal efficiency and uptake ability of Pontederia crassipes (a widespread hydrophyte in the karst area) from karst water. The Pb concentration, Pontederia crassipes morphology, and functional group were detected. As the HCO3− molarity in karst water increased (3, 4, and 5 mmol/L), the removal of Pb increased (85.31%, 93.28%, and 95.16%), whereas the bioconcentration amount of Pb decreased (573, 501, and 301 mg/kg), mainly due to the insoluble PbCO3 and Pb (OH)2. The Pb bioconcentration factor was the highest (15,564) at 4 mmol/L HCO3− due to the maximum strength of cation exchange and cell wall protein C=O. High HCO3− molarities changed the variety of positive ions of cation exchange (HCO3− ≤ 4 mmol/L: Na, K, and Mg; HCO3− > 4 mmol/L: Mg and K), and relieved the breaking of roots, stomatal closure, and vascular system shrinking. Moreover, high HCO3− molarities diminished the C≡C oxidation, enlarged the displacement of SO42− and C-O, and stimulated the methyl transfer reaction and the bonding between -CH3 and Pb. [ABSTRACT FROM AUTHOR]

In the investigation of sustainable materials, this study explores the viability of employing Lemon Activated Carbon (LAC) for the bio-adsorption of lead ions from e-waste bio-leachate. The novelty of this work lies in the comprehensive analyses of LAC characteristics, including particle size, surface area, zeta potential, and surface morphology. The morphology and adsorption capacity were measured using scanning electron microscope (SEM) and atomic absorption spectroscopy (AAS), confirming the efficacy of LAC in removing lead ions from the bio-leachate solutions. The surface area analysis unveiled that LAC, with a surface area of 603.7 m²/g achieved through thermal activation, exhibited competitive lead ion adsorption capacity despite its lower surface area compared to commercial-activated carbon (990 m²/g). Additionally, both LAC and CAC displayed pseudo-second-order kinetics for adsorption, with the Langmuir isotherm model fitting well (R2 = 0.9879) for LAC. The amorphous nature of LAC confirmed by X-ray diffraction (XRD) analysis and FTIR spectroscopy revealed functional surface groups, highlighting their suitability for lead ion adsorption. LAC comprised 75.82% carbon and exhibited maximum lead ion adsorption at pH 6. The optimized operating parameters achieved 89.16% lead ion removal from bio-leachate. These findings highlight the innovative utilization of lemon peel-derived activated carbon as a sustainable and environmentally friendly solution for mitigating the impacts of e-waste bio-leachate, thus contributing to the advancement of environmental remediation techniques.

In this study, magnetic biochar-iron oxide (MBC-IO) nanocomposite was easily synthesized as a strong adsorbent to remove toxic Pb(II) heavy metals from aqueous solutions. The physical and chemical properties of the prepared adsorbent were analyzed using SEM, FTIR, XRD, BET, and zeta-potential analyses. An experimental design, using the response surface methodology (RSM), was implemented to study the effect of operational parameters on the Pb(II) adsorption performance. The maximum adsorption capacity of MBC-IO nanocomposite was found to be 504 mg/g, at an adsorbent dosage of 0.08 g/L, pH 7, contact time of 10 min, and initial lead concentration of 50 mg/L. The kinetics and isotherm studies illustrated that the adsorption data were well described by pseudo-second-order and Langmuir models, respectively. In addition to rapid Pb2+ removal, the synthesized adsorbent was also employed to compare the adsorption capability of Cd2+, Co2+, and Ni2+ cations that had significant efficiency in the removal of heavy metals. The reusability investigation depicted that MBC-IO nanocomposite exhibits magnetic properties, enabling its facile separation from aqueous solutions with the assistance of an external magnetic field. These capabilities make the synthesized nanocomposite a good candidate for water purification industries. HIGHLIGHTS MBC-IO nanocomposite is able to remove several heavy metals with high efficiency in a short time.; The use of inexpensive materials in synthesizing MBC-IO nanocomposite and its high potential for reuse in the water purification process make it economically efficient.; MBC-IO nanocomposite can be easily separated from aqueous solutions using a magnetic field because of its magnetism.;

Abstract Contamination of water with heavy metals as lead (Pb2+) is a relevant problematic issue. In this work, we have tested different types of dendritic materials for lead removal from water and further recovery. The systems employed are magnetic nanoparticles (MNP) modified with monocarboxylate and dendritic carboxylate ligands, and they are compared to pristine MNP and carbosilane dendrimers. They are all effective at removing Pb2+, but the key variations are in their recyclability. The usage of a filtering membrane was required for dendrimers, which was significantly degraded by the acidic media. In terms of MNP, those that were covered by dendritic molecules were clearly less damaged in acidic media. Finally, isotherm analysis revealed that Pb2+ interacts differently with unmodified and modified MNP.

Global concerns about the preservation and restoration of aquatic environments are rising and pollution related to heavy metals is one of the main worries. Indeed, this issue has been a challenge for the metallurgical industry and other activities associated with metal contamination. Thus, over time, several physical and chemical methods have been developed and applied to remove metals from water. However, these methods can be associated with high costs, and bioremediation using plants, fungi, and bacteria is considered a viable alternative. This paper reports experiments on lead removal from an aqueous medium using active and inactive Serratia marcescens CCMA 1010 and a study on the effect of lead in this bacterial strain regarding the expression of the zntR gene, which produces the zntR protein known to have a role as a regulator of the ZntA efflux pump of metals (Pb2+, Cd2+, Zn2+). The amount of removed Pb2+ by active biomass remained below ∼25 mg/L for the initial concentrations tested up to 120 mg/L but increased to removals of ∼70 and ∼167 mg/L for the tested concentrations of 220 and 300 mg/L, respectively. On the other hand, the removal of Pb2+ by inactive biomass increased in direct relation to the initial tested concentration, with removed percentages around 25 %. Interestingly, in cultures with 15 and 60 mg/L Pb2+ the expression of zntR was 27 to 74 and 87 to 177 times lower (respectively) than in cultures without Pb2+, while in cultures with 120 mg/L Pb2+, the zntR expression was just 1.3 to 9.3 times lower than in the absence of Pb2+. The results confirm the potential of S. marcescens CCMA 1010 for Pb2+ biosorption, the presence of Pb2+ resistance mechanisms in this strain, and contribute to a better understanding of the ZntA transmembrane protein regulation.

In this study, bentonite/amino-functionalized cellulose composite (BAC) adsorbent was synthesized by intercalating the hexadecyl trimethyl ammonium bromide surfactant (HDTMA) into bentonite followed by exfoliating the HDTMA-modified bentonite (MB) into amino-functionalized cellulose (AC). The physicochemical properties of BAC were evaluated by FTIR, XRD, FE-SEM, EDX, TGA, and Zeta potential measurement. A series of batch mode adsorption experiments were carried out to identify the optimal adsorption conditions as a function of experimental variables such as pH of solution, uptake time, initial Pb2+ concentrations, BAC dosage, and assess both percent removal (%) and Pb2+ uptake (mg g−1). The result demonstrated that the synergetic advantage of combining HDTMA-modified bentonite (MB) and amino-functionalized cellulose (AC) in Pb2+ uptake (69 mg g−1) surpassed that of HDTMA-modified bentonite (12.14 mg g−1) and amino-functionalized cellulose (31.33 mg g−1) alone. Further, Pb2+ uptake onto BAC was higher than the HDTMA-modified bentonite/cellulose composite (BC) (42.12 mg g−1) due to the introduction of the amino group to cellulose through grafting with ethylenediamine (EDA). The adsorption of Pb2+ from aqueous solution by BAC fit well with pseudo - 2nd-order kinetic (R2 = 0.998) and Langmuir isotherm (R2 = 0.999) models. The kinetic study indicated that the active sites in the BAC exhibit heterogeneity and possess different activation energies for chemisorption. The monolayer attachment of Pb2+ onto the BAC surface was realized from the isotherm study, and the maximum predicted adsorption capacity was found to be 71.869 mg g−1. Regeneration studies showed that BAC maintained its good Pb2+ uptake capacity for up to four cycles.

This study reports the development of a novel biocomposite for potential applications in the environmental remediation. The hydroxyapatite/sodium bicarbonate (HAp-SB) biocomposite obtained by a cheap method could offer promising characteristics to be used in environmental applications. The obtaining of HAp-SB ceramic composites was studied with the aim of increasing the adsorption efficiency of lead ions from contaminated waters. A composite material (HAp-SB) with good crystallinity that preserves the hexagonal structure of pure hydroxyapatite was obtained. For the powder recovered after decontamination of the lead solution (PbHAp-SB), the XRD model highlighted additional maxima belonging to Ca 10 (PO 4) 5 (OH) 2 , Ca0.805Pb 4. 195 (PO 4)(OH) and PbH 2 P 2 O 7. The FTIR spectra of PbHAp-SB are similar to those of HAp-SB composites showing a broadening of the vibration peaks and a slight shift. The XPS and EDS studies illustrated the purity of the HAp-SB sample. Moreover, the presence of lead in the powder recovered after decontamination was also highlighted by XPS and EDS studies. The efficiency of HAp-SB in the adsorption of Pb2+ ions from the contaminated solution was also highlighted by ultrasound studies using double-distilled water as the reference liquid. The adsorption kinetics were investigated with the aid of Langmuir and Freundlich theoretical models. The results demonstrated that the HAp-SB ceramic composite has a strong affinity for the adsorption of Pb2+ ions from contaminated solutions. The removal efficiency of Pb2+ ions was about 92% for the initial Pb2+ concentration above 50 mg/L. The results of the cell viability and cytotoxicity studies demonstrated that HAp-SB nanoparticles did not influence negatively the HeLa cell's viability and did not induce any significant changes of the morphological features of HeLa cells after 24 h of incubation. The batch adsorption results as well as the cytotoxicity assay results suggested that the HAp-SB powder could be successfully used for the removal of Pb2+ from contaminated water. [ABSTRACT FROM AUTHOR]

Today, water pollutants such as heavy metals and dyes are serious dangers to nature. Metals such as lead, chromium, mercury, and arsenic are examples of heavy metals which are toxic to living things, even sometimes at the lowest concentrations. Magnetic nanoparticles are considerable compounds because of their advantages such as high efficiency, fast recovery capability, high surface area, easy transportation, and inexpensiveness. We presented an easy and eco-friendly method for the synthesis of iron oxide nanoparticles using Ziziphus jujuba extract. In order to determine the physical, chemical and optical properties of the synthesised samples, Fourier-transform infrared (FT-IR), powder X-ray diffraction (PXRD), vibrating sample magnetometer (VSM), field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), and Raman analyses were deployed. The PXRD results showed that the synthesised nanoparticles have a maghemite form of (γ-Fe2O3). The results showed that the synthesised nanoparticles were capable of removing 96% of lead at pH = 7 and 1 mg/L loading of nanoparticles. Adsorption isotherms of lead on nanoparticles as adsorbents were determined based on Freundlich and Langmuir adsorption isotherm models. The results showed that the best model of adsorption isotherm was Langmuir model. The photocatalytic activity of γ-Fe2O3 NPs was studied on methylene blue (MB) dye; as a result, MB at pH = 7 and 1 gr dosage of γ-Fe2O3 had the highest removal percentage (92.8%) during 160 minutes using γ-Fe2O3 which calcined at 400 °C. The reusability results showed that after four cycles of using the γ-Fe2O3-400, the obtained degradation of methylene blue was about 87.1%. Therefore, synthesised γ-Fe2O3 NPs can be a good alternative for removing heavy metals and industrial dyes from contaminated waters. [ABSTRACT FROM AUTHOR]

In this study, phosphoric acid was used to attach anions to the weak interlayer structure of sericite, one of the clay minerals composed of a tetrahedral structure of silicate, to increase the adsorption capacity of cations. Natural sericite beads (NSB) and activated sericite beads with phosphoric acid (PSB) were prepared as beads in order to increase reusability and facilitate the separation of adsorbates and adsorbents. Using this, lead (Pb(II)) removal efficiency from an aqueous solution was comparatively analyzed. The pHpzc was 6.43 in NSB but lowered to 3.96 in PSB, confirming that more acidic functional groups were attached to the PSB surface. According to FT-IR analysis, P=O, P-O-C, P=OOH and P-O-P bonds appeared on the surface of the PSB adsorbent, and the peaks of carboxyl groups and OH-groups were large and broad. The maximum adsorption capacity of Langmuir was 52.08 mg/g for NSB and 163.93 mg/g for PSB. The adsorption process was close to physical adsorption for NSB and chemical adsorption for PSB, and both adsorbents were endothermic reactions in nature in that the higher the temperature, the higher the adsorption efficiency. The adsorption mechanism of Pb(II) to PSB was achieved by ion exchange, electrostatic interaction, hydrogen bonding, and complexation. The adsorption of Pb(II) using PSB was not significantly affected by the adsorption of competing ions and showed a high adsorption efficiency of 94% in reuse up to 6 times. This confirms the favorable feasibility of removing Pb(II) from industrial wastewater using PSB. [ABSTRACT FROM AUTHOR]

Contamination of water with heavy metals as lead (Pb2+) is a relevant problematic issue. In this work, we have tested different types of dendritic materials for lead removal from water and further recovery. The systems employed are magnetic nanoparticles (MNP) modified with monocarboxylate and dendritic carboxylate ligands, and they are compared to pristine MNP and carbosilane dendrimers. They are all effective at removing Pb2+, but the key variations are in their recyclability. The usage of a filtering membrane was required for dendrimers, which was significantly degraded by the acidic media. In terms of MNP, those that were covered by dendritic molecules were clearly less damaged in acidic media. Finally, isotherm analysis revealed that Pb2+ interacts differently with unmodified and modified MNP. [ABSTRACT FROM AUTHOR]

Powdered leaves of Adhatoda vasica are used to investigate the adsorptive capacity of lead in a batch system. The conventional heavy metal removal approaches like ion exchange, membranes, precipitation, adsorption, etc. are proven, but are costly and harmful to the environment. The proposed approach explores the possibility of a biosorption technique for removing lead from aqueous solutions using A. vasica leaf powder. It is a low‐cost, non‐conventional, readily, and abundantly available plant‐based material. The equilibrium biosorption data was analyzed using the Langmuir, Freundlich, and Temkin isotherm models, with the Freundlich model providing the best description of the equilibrium dynamics. The kinetic analysis shows pseudo‐second order to be the best fit, revealing the spontaneous and endothermic nature of adsorption. The maximum biosorption capacity for lead is 5.903 mg g−1 indicating the adsorptive capacity of A. vasica under favorable process conditions. [ABSTRACT FROM AUTHOR]

Indonesia, notably in Central Kalimantan, has the potential for raw zirconia mineral, but it has not been successfully developed as a material that has ecologically friendly, high economic and technical value. The magnetic nanoparticles coated zirconia mineral was synthesized by using one-pot solvothermal processes, and then was used as adsorbent for water and wastewater treatment in adsorption process. Zirconia minerals are turned into composites with magnetic nanoparticles with the addition of hexane diamine to create the composite with amino groups (MH@ZrO2). It was then utilized as adsorbent to adsorb lead and cadmium metal in an artificial solution, and lower the metal content of lead/ (Pb(II)) and cadmium (Cd(II)) in it. The first stage was to determine the equilibrium of contact time (30, 60, 120, 240, and 360 min) of the adsorbent in binding Pb(II) and Cd(II) ions. The variations of pH 3, 5, 7, and 9 in the solution during adsorption were also examined to establish appropriate conditions for the adsorption process. The observations of magnetic nanoparticles composites based on a Scanning Electron Microscopy (SEM) analysis showed that magnetic nanoparticles with the diameter of 30–50 nm were generated on the face of zirconia minerals. X-Ray Diffraction (X-RD) analysis revealed that zirconia minerals treatment lowered the Crystallinity Index by 11.19% and the silica content by 98%. A Fourier Transform Infra-Red (FT-IR) spectrometer showed an adsorption peak of 590 cm−1 for the Fe-O bond on Fe3O4. Meanwhile, the optimum condition for Pb(II) and Cd(II) adsorption with pHe around 7 ± 0.2 for 360 min resulted in an adsorption density of 117.67 mg/g and 24.19 mg/g, respectively. The MH@ZrO2 led to development for high potential adsorbent due to stable material and easy separation, and capable for absorbing Pb(II) and Cd(II) ions from an aqueous solution.

Water pollution, driven by Pb2+, poses a significant threat to biotics and the environment. A promising solution to address the issue is the utilization of cellulose from lignocellulosic materials as an adsorbent to remove or reduce Pb2+ from wastewater. However, as reported, the adsorption capacities of native cellulose adsorbents vary depending on their plant source, and their metal binding capacity is not as satisfactory as expected due to a lack of robust chelation sites, particularly amino groups. Thus, this study aimed to improve Pb2+ uptake capacity by utilizing the prosopis juliflora stem, a previously unexplored cellulose source, as an adsorbent through ethylenediamine (EDA) grafting. FTIR, XRD, FE-SEM, EDX, and TGA evaluated the physicochemical properties of amino-decorated cellulose (ADC) adsorbent. The effect of experimental variables (initial Pb2+ concentration, ADC dose, and contact time) on percent removal was investigated and analyzed using Box-Behnken Design (BBD). Analysis of variance (ANOVA) revealed that, among the interaction effects, only the interactions between initial Pb2+ concentration and ADC dose significantly affected percent removal (P

Porous organic frameworks that are bound covalently are eye-catching materials in the current research. The present work describes the solvothermal synthesis of a combination of 3,3′,5,5′-tetramethyl-[1,1′-biphenyl] 4,4′-diamine and benzene-1,3,5-tricarbaldehyde through covalent bonding to generate TBBT-covalent organic framework (TBBT-COF). The structural, morphological, and computational characterizations confirm the formation of COF. TBBT-COF has been used as an adsorbent for the removal of Pb2+ ions from aqueous media. The effects of pH, initial metal ion concentration, competing ions, and adsorbent dosage were optimized to attain maximum adsorption of Pb2+. The kinetics follow pseudo-second-order and govern the chemisorption of Pb2+ with the imine group of TBBT-COF. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses of TBBT-COF after adsorption of Pb2+ support the chemisorption of Pb2+with TBBT-COF. The 2D contour and 3D surface response plots were used to assess the specific and comparative effects of the experimental variables. An analysis of variance (ANOVA) of the regression model was used to establish the relevance of the primary influencing variables on the adsorption of Pb2+over TBBT-COF. It was found to remove 99 % of Pb2+ in 90 min. The results of the real-sample analysis show the efficient removal of Pb2+ even in the presence of other cations. The statistical analysis of the adsorption has been conducted, which indicates the suggested models closely match the experimental data. The high surface area, covalency, and stability of TBBT-COF show its good adsorbent properties.

Pyrolysis is a promising thermochemical conversion process that transforms biomass into biochar, a carbon-rich solid material, in an oxygen-limited environment. This study focuses on the utilization of rice byproducts, namely rice straw and rice husk as feedstock for biochar production through low-temperature pyrolysis. The aim is to explore the potential of these biochars as cost-effective adsorbents for removing metal contaminants from aqueous solutions, with a particular emphasis on Pb(II) removal. Physicochemical properties of the biochars produced at a low temperature of 300 °C were thoroughly investigated, including surface morphology and their adsorption capacity for Pb(II). Remarkably, the rice straw biochar (RSB) produced at 300 °C exhibited exceptional Pb(II) adsorption capacity, with a value of 390.10±0.30 mg/g, and demonstrated a high Pb(II) removal efficiency of 96.10±0.30% when modified with 30% w/w H2O2. A crucial aspect of this study lies in the evaluation of the cost-effectiveness of the biochar production process, particularly when compared to commercially available adsorbents. By demonstrating the potential of rice byproduct-derived biochar as an efficient Pb(II) biosorbent in aqueous environments, this work not only provides new insights into the preparation of biochar using low-temperature pyrolysis but also offers a viable and economical solution for metal-contaminated water treatment. The findings of this research contribute to the field of sustainable waste utilization and highlight the significant potential of rice byproduct-based biochar as an environmentally friendly adsorbent for heavy metal removal. [ABSTRACT FROM AUTHOR]

Microporous sodium titanosilicate, Na2TiSiO5, has been successfully prepared using the sol–gel method. The structural and morphological characterization of synthesized product has been made via thermal analyses (TG-DTG), X-ray diffraction (XRD), and electron microscopy (SEM and TEM). Adsorption properties of the synthesized Na2TiSiO5 nanopowder for Pb(II) removal of aqueous media was investigated in different experimental conditions such as the contact time, the initial metal concentration, the pH, and the temperature. The Pb(II) adsorption on Na2TiSiO5 was discussed according to the kinetics and thermodynamics models. The adsorption kinetics of Pb(II) have been better described by the PS-order kinetic model which has the highest fitting correlation coefficients (R2: 0.996–0.999) out of all the other models. The adsorption results have been successfully fitted with the Langmuir and Redlich–Paterson models (R2: 0.9936–0.9996). The calculated thermodynamic parameters indicate that the Pb(II) adsorption is an endothermic process, with increased entropy, having a spontaneous reaction. The results have revealed a maximum adsorption capacity of 155.71 mg/g at 298 K and a very high adsorption rate at the beginning, more than 85% of the total amount of Pb(II) being removed within the first 120 min, depending on the initial concentration. [ABSTRACT FROM AUTHOR]

Lead (Pb) pollution adversely affects the growth and welfare status of various aquatic animals. Thus, the search for treating agents having the capability to remove Pb from the polluted wastewater is worthwhile. Hence, the two-stage polyurethane foam (PU) column was applied for lead (Pb) removal from industrial wastewater. The foam was packed into a column for easier use. The effect of different factors such as the weight of foam, the contact time and the pH degree were studied. Results revealed that the lead removal percent (LRP) was the best at pH 5 and 105 minutes for 4g PU/0.01 moles lead. The highest LRP reached 88% after the first stage and 98.6% after the second stage. The foam was used for Pb removal from a real sample of industrial wastewater. The LRP range was 62.1% - 88.2% for the tested samples after the first stage and 85.6% - 98.6% after the second stage. [ABSTRACT FROM AUTHOR]

Soil-washing using ethylenediamine-tetraacetate (EDTA) is an effective method for the remediation of lead (Pb) contaminated land. In practice, it is necessary to manage wastewater from this remediation process. The Electrocoagulation technique is an alternative method to remove Pb from soil-washing wastewater. The primary purpose of this study is to determine optimum conditions for the electrocoagulation process of Pb removal from soil-washing wastewater. This study used an electrochemical batch reactor with a monopolar parallel circuit. Based on the initial research, the Pb concentration in soil-washing wastewater was 3600 mg/L. Several parameters were used to obtain the optimal condition for Pb removal: operational voltage, type of electrode used, and time. The result showed that the optimum condition for Pb removal is on the operational voltage of 7 volt (V), using aluminium electrode pair, at an operating time of 80 min within the Pb removal efficiency of 96%. Furthermore, the kinetics study showed the highest Pb precipitation was 0.041/min following the first-order model. Using these optimal parameters, the Pb precipitation and removal efficiencies for real soil-washing wastewater were 0.0416/min and 96.7%, respectively. The electrocoagulation method is efficient for simultaneously removing lead from polluted effluents. [ABSTRACT FROM AUTHOR]

The present work is focused on an extensive comparative study of Pb (II) removal by organically tailored silica aerogels with the relevant studies. Briefly, two types of silica aerogels were synthesized using organic solvents, sol–gel method, modified aging techniques, and ambient pressure drying. The aerogels were characterized (SEM, XRD, FTIR) and investigated for Pb (II) removal from synthetic solutions and the results were extensively compared with other studies that synthesized aerogels using inorganic and expensive functionalizing/modifying agents. As per results of the comparative study, aerogel SA-Iso showed excellent removal efficiency and outperforming most of the functionalizing agents used by other studies, whereas SA-Sim showed remarkably decent results. Highest Pb (II) removal by both the aerogels was achieved in adsorbent dose experiments. At adsorbent dose of 0.1 g, pH 6, Pb (II) concentration of 10 ppm, solution volume of 100 mL, and contact time of 8 h, SA-Iso showed removal of 98.45%, which was higher than the removal achieved by functionalizing agents such as chitosan, bispyrazole, AAAPTS, thiamine, glutaraldehyde, TMCS, and hexane. On the other hand, SA-Sim removed 86.9% of Pb (II) ions which was higher than chitosan, bispyrazole, AAAPTS, and thiamine, respectively. The comparative study revealed that, under optimum conditions, such organically modified silica aerogels aged using the given aging techniques could result in an enhanced Pb (II) removal than silica aerogels modified with conventional functionalizing/modifying solvents. [ABSTRACT FROM AUTHOR]

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Real water remediation is an important issue that requires the development of novel adsorbents with remarkable adsorption properties, permitting reusability. In this work, the surface and adsorption properties of bare magnetic iron oxide nanoparticles were systematically studied, before and after the application of a maghemite nanoadsorbent in two real Peruvian effluents severely contaminated with Pb(II), Pb(IV), Fe(III), and others. We were able to describe the Fe and Pb adsorption mechanisms that occurred at the particle surface. 57Fe Mössbauer and X-ray photoelectron spectroscopy results together with kinetic adsorption analyses gave evidence for two involved surface mechanisms: (i) surface deprotonation of maghemite nanoparticles (isoelectric point of pH = 2.3), forming Lewis sites bonding Pb complexes; and (ii) the formation of a thin inhomogeneous secondary layer of iron oxyhydroxide and adsorbed Pb compounds, as favored by surface physicochemical conditions. The magnetic nanoadsorbent enhanced the removal efficiency to values of ca. 96% and provided adsorptive properties with reusability due to the conserved morphological, structural, and magnetic properties. This makes it favorable for large-scale industrial applications. [ABSTRACT FROM AUTHOR]

Emerging adsorption technology shows great potential for Pb2+ removal in the human body because of its high adsorption efficiency and easy operation. However, biosafety concerns in the human body limit the development of adsorbents in integrated lead removal for acute poisoning in humans from the gastrointestinal tract and even the blood. In this work, highly bio‐safe and natural saccharomyces cerevisiae cells are immobilized on the interworking natural regenerated cellulose nanofibers network for integrated lead removal in the human body. High intrinsic biosafety of the aerogel is guaranteed due to the biocompatibility of aerogel composition and the absence of cross‐linking substances. Attributing to the porous structure of cellulose nanofibrous scaffolds, saccharomyces cerevisiae cells are protected from shedding, and considerable loading sites for saccharomyces cerevisiae cells are ensured. Simultaneously, abundant functional groups on the saccharomyces cerevisiae cells exhibit superior adsorption ability with a saturated adsorption capacity of lead ions as high as 107 mg g−1 in the aquatic environment. After adsorption, Pb2+ concentration decreases from 879.70 to 248.53 µg L−1 in the intestinal phase and from 400 to 186.29 µg L−1 (within a safe level) in blood, providing an attractive strategy for detoxification of integrated lead in the human body. [ABSTRACT FROM AUTHOR]

Lead ions (Pb2+) as a typical toxic contaminant in the water resources cause health risk. In order to selectively remove Pb2+ from water, a novel adsorptive composite bead was prepared via introducing different functional metal-organic frameworks (MOFs) into alginate (Alg) hydrogel. The hydrogel-MOFs composite beads possessed the excellent adsorption towards Pb2+. The sulfonic-functionalized A-U6S composite beads showed the best adsorption performance of Pb2+ with the adoption capacity of 400.5 mg g-1 among three tested hydrogel-MOFs composite beads due to the specific affinity between Pb2+ and -SO 3 H. The Langmuir adsorption and pseudo-second-order kinetic models validated that Pb2+ was adsorbed by A-U6S in the manner of monolayer chemisorption on the surface of A-U6S composite beads. The thermodynamics study indicated that the interaction between A-U6S and Pb2+ was spontaneous and endothermic. Meanwhile, A-U6S showed higher adsorption capacity of Pb2+ in the coexistence of Cu2+, Cd2+, Zn2+ and Ca2+, exhibiting excellent selective adsorption towards Pb2+. The selectivity factors of Pb2+ versus Cu2+, Cd2+, Zn2+, and Ca2+ were 5.4, 5.7, 6.1 and 9.1. A-U6S composite beads can be reused five times with stable adsorption ability towards Pb2+ and till reached 94.2% of pristine adsorption capacity. Moreover, UiO-66(SO 3 H) powder can be collected and recycled after degradation of Alg by H 2 O 2 solution. The functionalized hydrogel-MOFs composite beads and the strategy for reuse and recycle of composite materials by the present study have great potential for practical applications in water purification treatment. [Display omitted] • Composite beads using alginate and UiO-66(SO 3 H) was synthesized. • The selective adsorption of composite beads for Pb2+ depends on sulfonic groups. • Alginate hydrogel assisted easy separation and recycle of composite beads. • Degradation of alginate in composite beads realized the recycle of UiO-66(SO 3 H). [ABSTRACT FROM AUTHOR]

Transvenous lead extraction (TLE) has shown a safe and efficacy profile in the intraoperative and short-term setting; however, data on long-term outcomes are limited. The purpose of this study was to assess long-term outcomes and prognostic factors in patients who underwent TLE. Consecutive patients with cardiac implantable electronic device (CIED) who underwent TLE between 2014 and 2016 were retrospectively studied. The primary outcome was the composite endpoint of death and repeated TLE stratified by infective/non-infective indication. Individual components of the primary outcome were also evaluated. One hundred ninety-one patients were included in the analysis, 50% extracted for CIED-related infection. Complete procedural success was achieved in 189 patients (99%) with no major acute complications. After a median of 6.5 years, infection indication was associated with significantly lower event-free survival (67% vs. 83% non-infection group, adjusted hazard ratio [aHR] 1.97, 95% confidence interval [CI] 1.02–3.81, p = 0.04). All-cause mortality rate was higher in the TLE infection group (30% vs. 10%, p < 0.01). The rate of repeated TLE did not differ between groups (4% vs. 7%, p = 0.62). Among patients who had TLE for infection, the presence of vegetation (aHR 2.56; 95%CI 1.17–5.63, p = 0.02) and positive blood cultures (aHR 2.64; 95%CI 1.04–6.70, p = 0.04) were independently associated with the primary outcome. Patients who underwent TLE for CIED-related infection exhibit a high mortality risk during long-term follow-up. Vegetation and positive blood cultures in patients with CIED-related infection are associated with a worse prognosis regardless of successful and uncomplicated TLE. • Patients who underwent TLE due to infection had a poor long-term prognosis. • Vegetations and systemic infection are predictors of death or repeated TLE. • Earlier TLE to limit vegetations and systemic infection spread should be recommended. [ABSTRACT FROM AUTHOR]

In this study, hydrothermal carbonization (HTC) at five temperatures (180, 200, 220, 240, and 260 °C) was applied to transform Paulownia leaves (PL) into a carbonaceous sorbent of Pb(II) from aqueous solutions. To enhance the adsorption efficiency of the obtained hydrochar (PH), subsequent alkali activation was performed using NaOH. Preliminary results of the Pb(II) adsorption (CPb = 200 mg/L) showed removal coefficients after 48 h of 73.44 mg/g, 82.37 mg/g, and 110.9 mg/g for PL, PH-220, and MPH-220, respectively. The selected hydrochar (PH-220) and modified hydrochar (MPH-220) were further investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results revealed that alkali treatment changed the hydrochar structure and, thus, improved its adsorption performance. The kinetic parameters showed that the Pb(II) sorption onto MPH-220 followed a pseudo-second-order model, while the intra-particle diffusion went through two simultaneous stages. The Langmuir isotherm model best described the experimental data and indicated the value of 174.75 mg Pb(II)/g as the maximum adsorption capacity. The two possible mechanisms of Pb(II) binding were complexation and/or Pb-π electron interaction. The obtained results indicate the great potential of MPH-220 for Pb(II) removal from aqueous media and its potential utilization as an effective adsorbent for wastewater purification. [ABSTRACT FROM AUTHOR]

Lead is a heavy metal that can be present in different types of effluents. This toxic ion is harmful both to human health and to other species. Therefore, it is necessary to study materials that can be used to remove lead from aquatic environments. In this context, the use of modified biomass residues for the production of efficient adsorbents for this purpose stands out. In this work was synthesized a new type of adsorbent material, sulfonated carbon, from macauba oil extraction residue for application in the removal of lead ions from aqueous media. The sulfonated carbons were produced from the reaction of macauba endocarp with concentrated sulfuric acid at 100 °C at 1, 2 and 4 h. The materials were characterized by XRD, MS-TG, Raman and infrared spectroscopies, SEM, potential titration, elemental analysis and by N2 adsorption/desorption. All synthetic conditions were efficient to produce functionalized carbonaceous materials with amorphous characteristics and good thermal stability. Although the material carbonized for 4 h had a low specific surface area (2 m2.g−1), it showed the higher efficiency for the removal of lead ions from aqueous solution. The adsorption occurred due to interactions of these ions with the functional groups present on the surface of the coal. The greatest lead removal occurred at pH 5.0 (83.8%), where –COOH and SO3H groups are in the deprotonated form, what favors the electrostatic attraction of Pb2+ ions. The experimental results were fitted using pseudo-first-order and pseudo-second-order models. A high concentration of lead ions was removed in the first 40 min, and the removal percentage was 97.5% for the less concentrated solution (10 mg·L−1) and 55.0% for the solution with the highest concentration (100 mg·L−1). The increase in the concentration of adsorbent provided an increase in the removal of this contaminant. The isotherm of adsorption was adjusted by Langmuir and Freundlich models. The better adjust was obtained by Langmuir and the maximum adsorption capacity by this model was 104.2 mg·g−1. The best lead removal conditions were: adsorbent concentration: 0.5 g.L−1; pH 5; Pb2+ concentration 80 mg.L−1 and time 2 h.