Lead removal from the aqueous solution by extracellular polymeric substances produced by the marine diatom Navicula salinicola

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.

[Lead Removal from Water by Calcium-containing Biochar with Saturated Phosphate]

Calcium-containing biochar （ES-BC） was prepared by pyrolyzing eggshell and kitchen wastes， and the ES-BC composite was used to remove phosphate （marked as ES-BC/P）. Based on the high affinity of phosphate and carbonate to lead， the ES-BC/P was then used to remove lead from the water. The results showed that， in the appropriate dosage， ES-BC/P could remove lead efficiently at different initial concentrations （1-100 mg·L-1）， and the removal efficiency could reach to 99%. Meanwhile， the release of phosphorus could be ignored after the reaction. As ES-BC/P was alkaline， and the lead-containing solution was weakly acidic， the addition of ES-BC/P could adjust the pH of the system automatically. The reaction kinetics and isotherm experiments showed that the lead removal by ES-BC/P was mainly monolayer chemisorption with a maximum adsorption capacity of 493.12 mg·g-1 （318 K）. The characterization results showed that lead was mainly removed through the ion exchanges of Pb2+ in the solution with Ca2+ in ES-BC/P. Then， the Pb2+ combined with CO32- and PO42- to form many precipitates， including Pb5（PO4）3OH， Pb10（PO4）6（OH）2， PbCO3， and Pb3（CO3）2（OH）2. In summary， the ES-BC/P material could achieve the efficient removal of lead from the water， thereby realizing the resource utilization of the wastes.

Design of a Novel Sericite-Phosphoric Acid Framework for Enhancement of Pb(II) Adsorption

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.

New Approaches for Pb(II) Removal from Aqueous Media Using Nanopowder Sodium Titanosilicate: Kinetics Study and Thermodynamic Behavior

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.

Surface Adsorption Mechanism between Lead(II,IV) and Nanomaghemite Studied on Polluted Water Samples Collected from the Peruvian Rivers Mantaro and Cumbaza

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.

Aqueous Pb(II) Removal Using ZIF-60: Adsorption Studies, Response Surface Methodology and Machine Learning Predictions

Zeolitic imidazolate frameworks (ZIFs) are increasingly gaining attention in many application fields due to their outstanding porosity and thermal stability, among other exceptional characteristics. However, in the domain of water purification via adsorption, scientists have mainly focused on ZIF-8 and, to a lesser extent, ZIF-67. The performance of other ZIFs as water decontaminants is yet to be explored. Hence, this study applied ZIF-60 for the removal of lead from aqueous solutions; this is the first time ZIF-60 has been used in any water treatment adsorption study. The synthesized ZIF-60 was subjected to characterization using FTIR, XRD and TGA. A multivariate approach was used to investigate the effect of adsorption parameters on lead removal and the findings revealed that ZIF-60 dose and lead concentration are the most significant factors affecting the response (i.e., lead removal efficiency). Further, response surface methodology-based regression models were generated. To further explore the adsorption performance of ZIF-60 in removing lead from contaminated water samples, adsorption kinetics, isotherm and thermodynamic investigations were conducted. The findings revealed that the obtained data were well-fitted by the Avrami and pseudo-first-order kinetic models, suggesting that the process is complex. The maximum adsorption capacity (q_max) was predicted to be 1905 mg/g. Thermodynamic studies revealed an endothermic and spontaneous adsorption process. Finally, the experimental data were aggregated and used for machine learning predictions using several algorithms. The model generated by the random forest algorithm proved to be the most effective on the basis of its significant correlation coefficient and minimal root mean square error (RMSE).

Removal of Lead from Wastewater Using Synthesized Polyethyleneimine-Grafted Graphene Oxide

In this work, polyethyleneimine-grafted graphene oxide (PEI/GO) is synthesized using graphene, polyethyleneimine, and trimesoyl chloride. Both graphene oxide and PEI/GO are characterized by a Fourier-transform infrared (FTIR) spectrometer, a scanning electron microscope (SEM), and energy-dispersive X-ray (EDX) spectroscopy. Characterization results confirm that polyethyleneimine is uniformly grafted on the graphene oxide nanosheets and, thus, also confirm the successful synthesis of PEI/GO. PEI/GO adsorbent is then evaluated for the removal of lead (Pb²⁺) from aqueous solutions, and the optimum adsorption is attained at pH 6, contact time of 120 min, and PEI/GO dose of 0.1 g. While chemosorption is dominating at low Pb²⁺ concentrations, physisorption is dominating at high concentrations and the adsorption rate is controlled by the boundary-layer diffusion step. In addition, the isotherm study confirms the strong interaction between Pb²⁺ ions and PEI/GO and reveals that the adsorption process obeys well the Freundlich isotherm model (R² = 0.9932) and the maximum adsorption capacity (q_m) is 64.94 mg/g, which is quite high compared to some of the reported adsorbents. Furthermore, the thermodynamic study confirms the spontaneity (negative ΔG° and positive ΔS°) and the endothermic nature (ΔH° = 19.73 kJ/mol) of the adsorption process. The prepared adsorbent (PEI/GO) offers a potential promise for wastewater treatment because of its fast and high uptake removal capacity and could be used as an effective adsorbent for the removal of Pb²⁺-ions and other heavy metals from industrial wastewater.

Hybrid Inorganic Organic PSF/Hap Dual-Layer Hollow Fibre Membrane for the Treatment of Lead Contaminated Water

Lead (Pb) exposure can be harmful to public health, especially through drinking water. One of the promising treatment methods for lead contaminated water is the adsorption-filtration method. To ensure the cost-effectiveness of the process, naturally derived adsorbent shall be utilised. In this study, hydroxyapatite particles, Ca₁₀(PO₄)₆(OH)₂ (HAP) derived from waste cockle shell, were incorporated into the outer layer of polysulfone/HAP (PSf/HAP) dual-layer hollow fibre (DLHF) membrane to enhance the removal of lead from the water source due to its hydrophilic nature and excellent adsorption capacity. The PSf/HAP DLHF membranes at different HAP loadings in the outer layer (0, 10, 20, 30 and 40 wt%) were fabricated via the co-extrusion phase inversion technique. The performance of the DLHF membranes was evaluated in terms of pure water flux, permeability and adsorption capacity towards lead. The results indicated that the HAP was successfully incorporated into the outer layer of the membrane, as visibly confirmed by microscopic analysis. The trend was towards an increase in pure water flux, permeability and lead adsorption capacity as the HAP loading increased to the optimum loading of 30 wt%. The optimized DLHF membrane displayed a reduced water contact angle by 95%, indicating its improved surface hydrophilicity, which positively affects the pure water flux and permeability of the membrane. Furthermore, the DLHF membrane possessed the highest lead adsorption capacity, 141.2 mg/g. The development of a hybrid inorganic-organic DLHF membrane via the incorporation of the naturally derived HAP in the outer layer is a cost-effective approach to treat lead contaminated water.

Multi-Walled Carbon Nanotubes Functionalized with Hydroxamic Acid Derivatives for the Removal of Lead from Wastewater: Kinetics, Isotherm, and Thermodynamic Studies

Hydroxamic acids are recognized chelators for various metals; however, using them as functional groups on carbon nanotubes (CNTs) is rare. In this study, novel multi-walled carbon nanotubes (MWCNTs) functionalized with hydroxamic acid derivatives were developed. The MWCNTs were first oxidized, and the resulting product, MWCNT-COOH (A), was treated with oxalyl chloride to yield MWCNT-COCl. The functionalized MWCNTs were susceptible to reacting with the hydroxylamine derivatives of type R–NHOH and produced MWCNTs functionalized with the following hydroxamic acid derivatives (MWCNT-HA): MWCNT-CONOHMe (B), MWCNT-CONOHCOMe(C), and MWCNT-CONOHPh (D). The synthesized derivatives were confirmed by various techniques such as scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. In order to examine their chelation ability, these materials were examined as possible new adsorbents for harmful Pb(II) particles. The adsorption efficiency of the functionalized MWCNT adsorbents toward Pb(II) was investigated. The effects of the adsorbent dose, temperature, pH, and time on adsorption efficiency were considered, and adsorption boundaries that resulted in enhanced effectiveness were obtained. The developed materials were found to have extraordinary coordination sites, such as amine, hydroxyl, and carboxyl groups, which served as excellent chelating specialists for the Pb(II) particles. Thermodynamic and kinetic investigations revealed the unconstrained nature of the adsorption of Pb(II) by the developed MWCNT adsorbents at room temperature. The adsorption was noted to follow the pseudo-second-order and Langmuir isotherm models.

Removal of lead ions from aqueous solution using new magnetic metal-organic framework

In this research, new magnetic nanocomposites that consist of NH₂-MIL53 (Al) and Fe₃O₄ nanoparticles functionalized with cysteine were synthesized and characterized. The application of these nanocomposites was investigated to remove lead ions from the wastewater model. The concentration of metal ions was measured by the utilization of flame atomic absorption spectroscopy (FAAS). Also, XRD, SEM, EDX, and FTIR instruments were used to identification and characterization of the synthesized nanocomposites. The effect of operating parameters such as; pH, contact time and adsorbent dosage were investigated on lead removal. The synthesized nanocomposite showed great potential for lead removal. The maximum adsorption capacity of the nanocomposite was about 361.53 mg/g. Adsorption kinetic parameters well fitted with the pseudo-second order kinetic model. The reusability test of the synthesized magnetic absorbent showed good adsorption efficiency for at least three consecutive cycles.

A Unique Enhancement of Propionibacterium freudenreichii's Ability to Remove Pb(II) from Aqueous Solution by Tween 80 Treatment

Microbial agents have promise for the bioremediation of Pb(II)-polluted environments and wastewater, the biodecontamination of foods, and the alleviation of toxicity in living organisms. The dairy bacterium Propionibacterium freudenreichii is poorly able to remove Pb(II) from aqueous solution at 25 ppm, ranging from 0 to 10% of initial concentration. Here, we report on an original strong enhancement of this activity (ranging from 75% to 93%, p < 0.01) following the addition of a polysorbate detergent (Tween® 80) during or either shortly after the growth of a P. freudenreichii culture. We evaluated the optimal Tween® 80 concentration for pretreatment conditions, documented the role of other detergents, and explored the possible mechanisms involved. Our results reveal a novel, environmentally friendly, low-cost pretreatment procedure for enhancing the selective removal of lead from water by probiotic-documented bacteria.

Investigating triple superphosphate for lead removal from aqueous solutions

The aim of this research is to investigate monocalcium phosphate monohydrate [Ca(H₂PO₄)_2. H₂O] also called triple superphosphate (TSP) for the removal of lead (Pb) from aqueous solutions. In this study, TSP was selected amongst various phosphate-based materials and fertilizers to act as the source of orthophosphate (PO₄^3-) which is a powerful tool for metal fixation in soil and water. Thermodynamic equilibrium dissolution-precipitation relationships for the systems of Pb-H₂O and Pb-PO₄^3--H₂O were drawn with the aid of Eh-pH stability diagrams to determine the predominance areas of different species. The lead phosphate compounds, identified through the stability area diagrams, were verified with the batch precipitation tests performed with standard solutions of lead and TSP at different conditions. It was observed that, depending upon solution conditions, TSP can precipitate 99.9% of the lead from the solution. Lead precipitates, analyzed by x-ray diffraction, showed the formation of lead phosphate compounds. The mechanism of TSP for the removal of lead from aqueous solutions is discussed.

Impact of Timing of Transvenous Lead Removal on Outcomes in Infected Cardiac Implantable Electronic Devices

BACKGROUND

Cardiovascular implantable electronic device (CIED) infections are associated with increased mortality and morbidity.

OBJECTIVE

This study sought to evaluate the impact of early versus delayed transvenous lead removal (TLR) on in-hospital mortality and outcomes in patients with CIED infection.

METHODS

Using the nationally representative, all-payer, Nationwide Readmissions Database, we evaluated patients undergoing TLR for CIED infection between January 1, 2016, to December 31, 2018. The timing of the TLR procedure was determined based on hospitalization days after initial admission for CIED infection. The impact of early (≤ 7 days) versus delayed (> 7 days) TLR on mortality and major adverse events was studied.

RESULTS

Of 12,999 patients who underwent TLR for CIED infections, 8,834 patients underwent early TLR versus 4,165 patients who underwent delayed TLR. Delayed TLR was associated with a significant increase in in-hospital mortality (8.3% vs. 3.5%, adjusted odds ratio:1.70; 95% confidence interval, 1.43-2.03; P value<0.001). Subgroup analysis of patients with CIED infection and systemic infection showed that delayed TLR in patients with systemic infection was associated with a higher rate of in-hospital mortality compared with early TLR (10.4% vs. 7.5%, adjusted odds ratio:1.24; 95% confidence interval, 1.04-1.49; P value<0.019). Delayed TLR was also associated with significantly higher adjusted odds of major adverse events and post-procedural length of stay.

CONCLUSIONS

These data suggest that delayed transvenous lead removal in patients with CIED infections is associated with increased in-hospital mortality and major adverse events, especially in patients with systemic infection.

2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

Procedural outcome of lead explant and countertraction-assisted femoral lead extraction in Thai patients with cardiac implantable electronic device infection

BACKGROUND

Cardiac implantable electronic device (CIED) implantation rate has been increasing worldwide. Despite proper surgical technique and preincisional intravenous antibiotics, the incidence of infected CIED remains high and leads to serious complications. When encountered with CIED infection, complete CIED system removal is indicated. Several lead extraction approaches have shown a high success rate. However, the facilities are limited in Thailand. In our current practice, we perform lead extraction using the Dotter basket snare femoral approach as our primary method. There are no prior data on this countertraction-assisted transfemoral technique. Therefore, we aim to study the procedural outcome of countertraction-assisted transfemoral lead removal technique of CIED infection in Thai patients.

METHODS

Patients diagnosed with CIED infection and with a history of device infection were retrospectively included. Simple manual removal was performed. In case of failure, we proceeded with the modified countertraction-assisted transfemoral technique.

RESULTS

There were 35 patients in the study. The success rate was 94.3%. Most of the leads, 62.8%, were removed by simple manual traction. In the 37.1% who required further femoral approach lead extractions, procedural failure was observed in 5.7% and procedure-related adverse events in 5.6%. CIED infection-related death accounted for 5.7% and nosocomial infection-related death, 2.8%.

CONCLUSION

The success rate of CIED infection lead explant and countertraction-assisted transfemoral lead extraction technique was high with small complications and can be performed without advanced facilities. However, the procedure required a main center with a cardiovascular thoracic surgery support team.

Graphene Oxide as a Pb(II) Separation Medium: Has Part of the Story Been Overlooked?

A key problem associated with the design of graphene oxide (GO) materials and their tuning for nanoscale separations is how specific functional groups influence the competitive adsorption of solvated ions and water at liquid/graphene interfaces. Computation accompanied by experiment shows that OH and COOH exert an influence on water adsorption properties stronger than that of O and H functional groups. The COO- anions, following COOH deprotonation, stabilize Pb(II) through strong electrostatic interactions. This suggests that, among the functional groups under study, COOH offers the best Pb(II) adsorption capacity and the ability to regenerate the sorbent through a pH swing. In line with computation, striking experimental observations revealed that a substantial increase in Pb(II) adsorption occurs with increasing pH. Our findings provide a systematic framework for controlled design and implementation of regenerable C-based sorbents used in separations and desalination.

Iron Oxide Nanoparticles: Biosynthesis, Magnetic Behavior, Cytotoxic Effect

Iron oxide nanoparticles have attracted much attention because of their superparamagnetic properties and their potential applications in many fields such as magnetic storage devices, catalysis, sensors, superparamagnetic relaxometry (SPMR), and high-sensitivity biomolecule magnetic resonance imaging (MRI) for medical diagnosis and therapeutics. In this study, iron oxide nanoparticles (Fe2 O3 NPs) have been synthesized using a taranjabin (camelthorn or persian manna) aqueous solution. The synthesized Fe2 O3 NPs were identified through powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), field energy scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDX), vibrating-sample magnetometer (VSM) and Raman technics. The results show that the nanoparticles have a hexagonal structure with 20 to 60 nm in size. The cytotoxic effect of the synthesized nanoparticles has been tested upon application against lung cancer cell (A549) lines. It was found that there is no cytotoxic activity at lower concentrations of 200 μg/mL. The ability of the synthesized nanoparticles for lead removal in wastewaters was tested. Results show that highest concentration of adsorbent (50 mg/L) has maximum removal efficiency (96.73 %). So, synthesized Fe2 O3 NPs can be a good candidate to use as heavy metals cleaner from contaminated waters.

Improved Removal Capacity and Equilibrium Time of Maghemite Nanoparticles Growth in Zeolite Type 5A for Pb(II) Adsorption

Novel magnetic zeolite type 5A nanocomposites were synthesized by the co-precipitation method and applied to lead removal from aqueous ambient. Maghemite nanoparticles were mixed with zeolite and, by controlling its content, transmission electron microscopy results gave sizes of 5 to 15 nm and selected area electron diffraction patterns confirmed the presence of zeolite. The nanocomposites have high specific surface area with values up to 194 m²/g. Magnetization measurements proved superparamagnetic behavior with saturation values of ~35 emu/gFe. Kinetic adsorption experiments showed removal efficiencies of 99.9% and an enhanced equilibrium time of 5 min. The lead concentrations after adsorption experiments lay under the permissible levels of 10 μg L⁻¹, according to the World Health Organization. The maximum adsorption capacity, estimated by Sips model, was 265 mg L⁻¹ at 300 K. The removal efficiency was significantly improved in the range of pH > 6, as well as in the presence of cation interferents such as Ca(II), Cu(II), and Cd(II). The adsorption mechanism was explained with cation exchange between Pb(II), the zeolite framework, and the protonated maghemite surface. Besides, our system revealed recyclability even after seven regeneration cycles. Thus, our synthesized materials have remarkable adsorption properties for lead water remediation processes.

Extraction of Microfibrillar Cellulose From Waste Paper by NaOH/Urethane Aqueous System and Its Utility in Removal of Lead from Contaminated Water

Though recycling of waste paper is widely practiced but usually it is downgraded to lower valued recycled waste paper. Based on this concern, we report the development of novel NaOH/urethane aqueous system for extraction of microfibrillated cellulose from waste paper. The purity of so obtained microfibrillated cellulose (MFC) was evaluated by morphological tests using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and by evaluation of physicochemical properties using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Morphologies of MFC studied by SEM and TEM showed that the size of purified cellulose fibrils reduced when compared to that of waste paper but fibrils are cleaner and smoother due to the removal of talc and lignin. XRD analysis revealed that MFC exhibits good crystallinity. The utility of sulfonated and pristine microfibrillar cellulose in removal of lead from contaminated water is also reported. Our results show that renewable, sustainable, cheap, and waste biomass like waste paper can be used for producing valuable second-generation high-value products.

Transvenous lead extraction after heart transplantation: How to avoid abandoned lead fragments

BACKGROUND

Many patients awaiting heart transplantation (HTX) have a cardiac implantable electronic device (CIED). Lead removal is often still a part of the HTX procedure. Abandoned lead fragments carry a risk for infections and prohibit magnetic resonance imaging (MRI) imaging. This study evaluated the concept of an elective lead management algorithm after HTX.

METHODS AND RESULTS

Between 2009 and 2018, 102 consecutive patients with previously implanted CIED underwent HTX. Lead removal by manual traction during HTX was performed in 74 patients until December 2014. Afterward, treatment strategy was changed and 28 patients received elective lead extraction procedures in a hybrid operating room (OR) using specialized extraction tools. Total of 74 patients with 157 leads underwent lead extraction by manual traction during HTX. The mean lead age was 32.3 ± 38.7 months. Postoperative X-ray revealed abandoned intravascular lead fragments in 31(41.9%) patients, resulting in a complete lead extraction rate of only 58.1%. The high rate of unsuccessful lead extractions led to the change in the extraction strategy in 2015. Since then, HTX was performed in 28 CIED patients. In those patients, 64 leads with a mean lead age of 53.8 ± 42.8 months were treated in an elective lead extraction procedure. No major or minor complications occurred during lead extraction. All leads could be removed completely, resulting in a procedural success rate of 100%.

CONCLUSION

Our results demonstrate that chronically implanted leads should be removed in an elective procedure, using appropriate extraction tools. This enables complete lead extraction, which reduces the infection risk in this patient population with the necessity for permanent immunosuppressive therapy and allows further MRI surveillance.

Incidental detection of single coil right ventricular lead perforation during aortic valve surgery

It is unknown how many pacemaker and implantable cardioverter defibrillator (ICD) leads perforate during lead placement. Symptoms of a perforated lead include shortness of breath and chest pain. Signs of perforation can include a high pacing threshold, reduced lead sensing, and a high lead impedance. We present the case of a patient where perforation of the single coil right ventricular lead was not evident in imaging but incidentally detected during operative aortic valve replacement. The lead perforation rate during device implantation is around 1%-ICD leads have a higher perforation rate.

Hydration of Ordinary Portland Cement in Presence of Lead Sorbed on Ceramic Sorbent

Lead, a highly toxic element, is frequently present in various solid wastes as well as in industrial effluents. Sorption with a low cost sorbent is a simple way of Pb removal from liquid streams, but stabilization of spent sorbent has to be ensured in order to prevent Pb leaching out and possible environmental contamination. In previous research, ceramic sorbent, generated as waste product in brick industry, was tested as sorbent and proved high sorption capacity for lead. Lead was sorbed partially as hydrocerussite and partially as adsorbed surface layer. The Pb leaching from sorbent was very high and thus further immobilization of sorbent was necessary. Lead, as well as other heavy metals, is known as retarder of the hydration process of Ordinary Portland Cement (OPC), used for the immobilization. In this paper, influence of sorbed Pb and PbO, as reference compound, on cement hydration was studied by calorimetry, thermogravimetry and Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy (MAS NMR). The sorbed lead was found to be less detrimental to hydration retardation due to the lower solubility of precipitated hydrocerussite in basic environment compared to PbO, which forms plumbate anion.

Lead Extraction of Cardiac Rhythm Devices: A Report of a Single-Center Experience

Introduction and objectives

The rate of implanted cardiac electronic devices is increasing as is the need to manage long-term complications. Lead removal is becoming an effective approach to treat such complications. We present our experience in lead removal using different approaches, analyzing the predictors of the use of mechanical extractors/surgical removal.

Methods

Retrospective analysis of lead extractions in a series of 76 consecutive patients (mean age 70.4 ± 13.8 years, 73.7% men) between January 2009 and November 2015.

Results

One hundred thirty-five leads from permanent pacemakers (single chamber 19.7%; dual-chamber 61.8%), implantable cardioverter defibrillators (5.3%), and cardiac resynchronization devices (CRT-P 2.6%; CRT-D 7.9%) were removed, 72.5 ± 73.2 months after implantation. A total of 45.9% were ventricular leads, 40.0% atrial leads, 8.9% defibrillator leads, and 5.2% leads in the coronary sinus; 64.4% had passive fixation. The most common indications for removal were pocket infection (77.8%), infective endocarditis (9.6%), and lead dislodgement (3.7%). A total of 76.3% of the leads were explanted, 20.0% were extracted, and 3.7% were surgically removed. Extraction of the entire lead was achieved in 96.3% of the procedures. After logistic regression (age adjusted), time since implantation was the sole predictor of the need of mechanical extractors/surgical removal. All patients were discharged without major complications. There were no deaths at 30 days.

Conclusion

Our experience in lead removal was effective and safe. Performing these procedures by experienced electrophysiologists with an adequate cardiothoracic surgery team on standby to cope with any complications is required. Referral of high-risk patients to a high-volume center is recommended to optimize clinical success and minimize procedural complications.

Core-Shell Ferromagnetic Nanorod Based on Amine Polymer Composite (Fe3O4@DAPF) for Fast Removal of Pb(II) from Aqueous Solutions

Heavy metal ion removal from wastewater constitutes an important issue in the water treatment industry. Although a variety of nanomaterials have been developed for heavy metal removal via adsorption, the adsorption capacity, removal efficiency, and material recyclability still remain a challenge. Here, we present novel Fe3O4@DAPF core-shell ferromagnetic nanorods (CSFMNRs) for the removal of Pb(II) from aqueous solutions; they were prepared by the facile surface modification of twin-like ferromagnetic Fe3O4 nanorods using a 2,3-diaminophenol and formaldehyde (DAPF)-based polymer. The crystallinity and structure of the Fe3O4 nanorods were confirmed via X-ray diffraction (XRD). Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) revealed the core-shell morphology and composition of the materials. Pb(II) removal using the prepared Fe3O4@DAPF CSFMNRs was assessed, and comparable adsorption capacities (83.3 mg g(-1)) to the largest value were demonstrated. A thermodynamic study of the adsorption clearly indicated that the adsorption was exothermic and spontaneous. Due to the ferromagnetic properties with a high saturation magnetization value (56.1 emu g(-1)) of the nanorods, the nanorods exhibited excellent reusability with one of the fastest recovery times (25 s) among reported materials. Therefore, the Fe3O4@DAPF CSFMNRs can serve as recyclable adsorbent materials and as an alternative to commonly used sorbent materials for the rapid removal of heavy metals from aqueous solutions.

Outcomes and Complications of Lead Removal: Can We Establish a Risk Stratification Schema for a Collaborative and Effective Approach?

BACKGROUND

Removal of an entire cardiovascular implantable electronic device is associated with morbidity and mortality. We sought to establish a risk classification scheme according to the outcomes of transvenous lead removal in a single center, with the goal of using that scheme to guide electrophysiology lab versus operating room extraction.

METHODS

Consecutive patients undergoing transvenous lead removal from January 2001 to October 2012 at Mayo Clinic were retrospectively reviewed.

RESULTS

A total of 1,378 leads were removed from 652 (age 64 ± 17 years, M 68%) patients undergoing 702 procedures. Mean (standard deviation) lead age was 57.6 (58.8) months. Forty-four percent of leads required laser-assisted extraction. Lead duration (P < 0.001) and an implantable cardioverter defibrillator (ICD) lead (P < 0.001) were associated with the need for laser extraction and procedure failure (P < 0.0001 and P = 0.02). The major complication rate was 1.9% and was significantly associated with longer lead duration (odds ratio: 1.2, 95% confidence interval: 1.1-1.3; P < 0.001). High-risk patients (with a >10-year-old pacing or a >5-year-old ICD lead) had significantly higher major events than moderate-risk (with pacing lead 1-10 years old or ICD lead 1-5 years old) and low-risk (any lead ≤1-year-old) patients (5.3%, 1.2%, and 0%, respectively; P < 0.001).

CONCLUSIONS

Transvenous lead removal is highly successful, with few serious procedural complications. We propose a risk stratification scheme that may categorize patients as low, moderate, and high risk for lead extraction. Such a strategy may guide which extractions are best performed in the operating room.

Inadvertent transarterial lead placement in the left ventricle and aortic cusp: percutaneous lead removal with carotid embolic protection and stent graft placement

Background/Purpose

Transarterial lead implantation in the left ventricle or aorta is a rare complication. Percutaneous lead removal is associated with significant thromboembolic and bleeding risk. We present two cases of lead removal from the left ventricle via the left subclavian artery with concurrent carotid embolic protection followed by stent graft placement in the subclavian artery.

Methods/Results

Patient 1 underwent prior pacemaker implant with atrial and ventricular active fixation leads positioned in the right coronary cusp and the left ventricle, respectively. Patient 2 had prior ICD implant with a single active fixation lead positioned in the left ventricular apex. Lead removal was performed in a hybrid operating room. Distal embolic filter wires were deployed in the carotid arteries following anticoagulation. Intravascular ultrasound of the left subclavian artery was performed and as the leads were withdrawn, a covered stent was deployed at the removal site. Final angiography demonstrated no evidence of embolic phenomena. Both patients underwent transvenous lead implantation followed by an uneventful postoperative clinical course.

Conclusions

Transarterial percutaneous lead removal may be safely performed using embolic filter protection of the cerebral circulation and stent graft placement of the arterial entry site.