Mixture Of Pb Research Articles

Preparation and characterization of jatropha curcas leaves as a biosorbent for Pb(II) and Cd(II) removal in liquid waste

This study aims to determine the capacity of Jatropha leaves to absorb Pb (II), Cd (II) and their mixture in liquid waste. Jatropha leaves were obtained from Durian, Labu Beach, North Sumatra, heated for 4 hours and 24 hours, then characterized by XRD, FTIR, and SEM. XRD and FTIR spectra confirmed there are no structural differences of Jatropha leaf biosorbent with 4 hours and 24-hour pretreatment. SEM images indicate that the surface of the biosorbent prepared for 24 hours is smoother than the 4-hour preparation. The number of Jatropha leaves which absorbed Pb (II) and Cd (II) were measured with AAS and the optimum concentration of 0.5 gram of adsorbent for Pb (II) is 80 ppm (90 minutes) adsorbed up to 95.52%. It is higher than the absorption of Cd(II) which is 76.37% at a concentration of 100 ppm (90 minutes). But the mixture of Pb (II) and Cd (II) induce the opposite result. Cd (II) was absorbed more by 92.48% while Pb (II) was 88.62% at a concentration of 100 ppm for 90 minutes. Although Pb (II) can be absorbed more than Cd (II), when the two heavy metals mixed, Cd (II) is absorbed more than Pb (II).

The sublethal lead (Pb) toxicity to the earthworm Eisenia fetida (Annelida, Oligochaeta) as affected by NaCl salinity and manure addition in a calcareous clay loam soil during an indoor mesocosm experiment.

The combined effects of salinity and organic amendments on lead (Pb) toxicity to earthworms as important components of soil invertebrates are still largely unknown. A mesocosm experiment was conducted to examine how the combined use of NaCl salinity and cow manure would affect the sublethal Pb toxicity to chronically exposed Eisenia fetida in natural soil. The response of life-cycle parameters of this earthworm species and biological properties to NaCl-induced salinity (0, 4 and 8dSm-1) was determined in a Pb-contaminated clay loam soil amended or unamended with fresh cow manure. The NaCl salt and cow manure (4%, w/w) were added to the soil and the mixtures were incubated for 90 days under greenhouse conditions. The results showed that NaCl salinity increased soil Pb availability and toxicity, increased earthworm Pb concentration and uptake, and decreased earthworm survivorship, population (adults and juveniles), reproduction, wet weight, cocoon production, and cast activity. The detrimental effects of NaCl salinity on earthworms and biological properties were greater at high than low salinity levels. Addition of cow manure lowered the NaCl-induced Pb toxicity to earthworms at all salinity levels, suggesting the harmful effect of salinity-induced Pb toxicity was reduced due to the decreased Pb availability following manure application. This study demonstrated that soil salinity and animal manures can have a great impact on the life-cycle endpoints and activity of E. fetida, which requires attention when using saline waters for irrigation and organic amendments for soil amelioration in Pb-contaminated environments. It is concluded that (i) the multiple stresses induced by salinity and Pb mixtures may negatively affect earthworms and (ii) organic amendment application has a high potential for lowering the stronger negative effect of salinity in Pb-polluted environments and for improving earthworm population, reproduction and activity.

The surface modification of aluminum by mechanical milling of Pb coating and high current pulsed electron beam irradiation

This paper reports the surface morphology and properties of Al substrates with Pb coating, which was deposited by mechanical milling and then treated by high current pulsed electron beam (HCPEB) irradiation. After HCPEB irradiation treatment, some previously formed defects such as micro-pits, craters, and bulged nodules were eliminated, resulting in significant reduction of surface roughness of initial Pb/Al sample, and the formation of a dense and adherent Pb/Al alloying layer. Notably, when the number of irradiation pulses reached 30, there was uniform distributions of Pb in the mixture of Pb and Al elements in the milled samples, which resulted in the formation of gray layers with thickness of 12 μm (milling for 1 h) and 8 μm (milling for 2 h). These formed layers effectively improved the wear resistance. Moreover, the hardness of Pb/Al sample also improved after HCPEB irradiation due to structure defect strengthening and ultra-fine Pb-rich particles reinforcement. The above results demonstrate that HCPEB treatment is an effective method to obtain high-quality alloy coating layer, resulting in the formation of an excellent alloy.

Stability of Sn based inorganic perovskite quantum dots

Metal halide perovskite crystal structures have emerged as a class of optoelectronic materials, which combine the ease of solution processability with excellent optical absorption and emission qualities. However, the most promising perovskite structures rely on lead as a cationic species, thereby hindering commercial application. The replacement of lead with non-toxic alternatives such as tin has been studied in bulk but not in nanocrystals. In this work, we synthesize Sn and Pb based alloy perovskite nanocrystals by direct synthesis method, taking mixture of Pb and Sn precursors in the desired ratio leading to quantum dots (QDs) of CsPb1−xSnxBryI3−y with successful Sn incorporation into the host lattice. As colloidal stability of these QDs is a crucial factor for device applications, we have studied the stability of the QDs under different conditions for these Sn based QDs and have found them to degrade faster upon using anti-solvents during washing process. In order to stabilize them, we have devised a purification method that is also discussed. Further, even though the optical and crystal structure stability in some of the inorganic perovskites leaves much room for improvement, so far there have been no studies on the structure property correlation. Here we study their structural purity and their optical stability after understanding the structure property correlation in CsPbI3 and CsPbBr3 perovskite structures. The stability of Sn doped perovskites obtained from a logical understanding of structure property correlation is found to be extremely stable across the series of compounds for upto three months.

Clean Recycling Process for Lead Oxide Preparation from Spent Lead–Acid Battery Pastes Using Tartaric Acid–Sodium Tartrate as a Transforming Agent

A clean recycling process for waste lead–acid battery paste was proposed, where tartaric acid-sodium tartrate mixed solution was used as the transforming agent. First, lead tartrate [Pb(C4H4O6)] was prepared by the reaction of paste and the transforming agent, and then it was calcined to obtain lead oxide powder. The lead recovery rate and desulfurization rate were 97.55% and 99.02%, respectively. In addition, pure lead tartrate was obtained with a narrow particle size distribution. Next, the thermal behavior of lead tartrate was investigated, and the results show that it rapidly decomposed into PbO in air and remained stable until 800°C. However, in an argon atmosphere, the weight loss rate approached that of metallic lead generation. The study of the calcination of lead tartrate in air and argon atmospheres showed that the main product was a PbO and Pb mixture; however, the product morphologies were different. Ultra-fine lead oxide particles with a particle size < 100 nm were obtained by calcining in an argon atmosphere. With increasing calcination temperature, more metallic lead was formed. The main advantages of this process are the use of a clean and non-toxic transforming agent and the direct production of ultra-fine lead oxide through calcination.

Electrochemically Assembled Cu2O Nanoparticles Using Crystallographically Anisotropic Functional Metal Ions and Highly Expeditious Resistive Switching via Nanoparticle Coarsening.

We have developed an artificially controllable strategy of an electrodeposition process adequate for resistive random-access memory (ReRAM) applications of binary Cu2O. Typically, the precise control of OH- ion concentration (the intermediate supplier of oxygen ions) at the electrode's surface decides the overall reaction rate of the Cu2O. Here, the suggested Pb and Sb metal additives preferentially contribute to the consumption of OH- ions and the supply of OH- ions, respectively, during the Cu2O electrochemical reaction so that the final products are the (200) preferential quadrangular pyramids and the (111) preferential triangular pyramids. Interestingly, the coexistence of Sb/Pb precursors in the Cu electrolytes results in extraordinarily decreased reaction rate from the opposite action of OH- ion utilization as well as intense progressive growth behavior, and the resultant Cu2O films consist of crystallized small-size nanoparticles (NPs) in an amorphous-like matrix. In the case of ReRAM applications, while the polycrystalline film induces irregular device performance and the amorphous layer shows an easily irreparable electrical breakdown, our NP-assembled Cu2O films from Pb/Sb metal ions reveal the formation of a conduction bridge via phase change to a crystalline filament with no need for forming voltage and with superior electrical stability. It is attributed to the coalescence of crystal NPs into large grains during the set/reset cycle process for the heat dissipation of Joule heating. The Cu2O sample prepared with a 3 mM Sb + 3 mM Pb mixture solution exhibits forming-free ReRAM devices with high on/off resistance ratios of 1.2 × 104 and long-term electrical/thermal stability.

Cadmium impact on the phytotoxicity of lead to spring barley Hordeum vulgare

&lt;p&gt;The aim of the study was to determine cadmium influence on the lead phytotoxicity to spring barley (Hordeum vulgare L.). The seedlings of H. vulgare were treated with single Pb (ranging from 0.1 to 100 mg l-1) and Pb mixture with Cd. Plant biomass production, physiological response, induction of oxidative damage and metals accumulation in roots and shoots were evaluated. Single Pb and under the presence of cadmium impaired the growth of H. vulgare, altered the content of photosynthetic pigments and induced lipid peroxidation. The addition of Cd to the Pb treatments has led to additive or synergistic effects on H. vulgare shoot and root dry weight, oxidative damage and increased bioaccumulation. The interactive effect of these metals on the content of photosynthetic pigments was concentration range dependent. Additivity was detected when H. vulgare were exposed to low concentrations of Cd and Pb and high concentrations of these metals had lower than additive effect.&lt;/p&gt;&#x0D;

Application of Stabilized Nano Zero Valent Iron Particles for Immobilization of Available Cd2+, Cu2+, Ni2+, and Pb2+ Ions in Soil

The present manuscript studies the effectiveness of commercial nano zero valent iron (nZVI) particles in decreasing the availability of Cd, Cu, Ni, and Pb in spiked soil samples and to remove the same heavy metals from aqueous solutions. The difference of nZVI efficiency between single and multi-metal contamination was evaluated. The application of nZVI in water samples showed higher effectiveness in the cases of single metal contamination. The effectiveness of single- and multi-metal (mixtures of Cu, Ni, Pb and Cd, Cu, Ni, Pb) immobilization in soil using different doses (0%, 0.85%, 1.7%, 2.55%, and 5.1%) of nZVI was determined. Immobilization efficiency was assessed using the leaching procedure and depended on a particular metal and the dose of nZVI. In all cases, it was determined that an increasing amount of nZVI resulted in decrease in the leaching of analysed metals. In cases, where higher nZVI doses were used, higher immobilization efficiency was observed for heavy metals in multi-metal contamination. The application of nZVI significantly reduced leaching of all heavy metals and this strategy can be successfully used for heavy metals stabilization in soils.

Maternal exposure to low dose BDE209 and Pb mixture induced neurobehavioral anomalies in C57BL/6 male offspring

Polybrominated diphenyl ethers (PBDEs) and lead (Pb) are common pollutants that co-exist in the environment. These chemicals may be associated with autism spectrum disorder (ASD), yet direct evidence is lacking. More importantly, how co-exposure of these chemicals might affect ASD has never been explored. For assessing the relationship between PBDE/Pb exposure and ASD, pregnant C57BL/6 J female mice were exposed to BDE209 (0.12 ng/day), Pb (1.2 ng/day), or a BDE209/Pb mixture from gestational day (GD) 9.5 to postnatal day (PND) 21 using ALZET osmotic pumps. Polyinosinic-polycytidylic acid (poly I:C) was included as a positive control, as its single dose injection (20 mg/kg.bw; i.p.) at mid-pregnancy (GD 12.5) produces ASD-like behaviors in mouse offspring. These ASD-like phenotypes include decreased preference for social novelty, increased marble burying behavior, and learning impairment. Similar to the poly I:C control, perinatal exposure to Pb or BDE209/Pb mixture elicited increased marble burying and learning impairment, but it had no effect on sociability. Consistent with these behavioral anomalies, Pb and BDE209/Pb co-exposure as well as poly I:C exposure increased the production of pro-inflammation cytokines interleukin 4 (IL-4), interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor α (TNFα), interferon γ (IFNγ), and interleukin 17 A (IL-17 A) in the serum, and decreased neuronal cells in the CA1 and CA3 subregions of the hippocampus. The majority of these changes in the BDE209/Pb mixture group were due to the effect of Pb rather than BDE209. However, BDE209/Pb co-exposure elicited a synergistic increase in the production of IL-4, IL-6, TNFα, IFNγ, and IL-17A in the serum. BDE209 exposure alone also significantly affected spatial learning and increased the production of IL-10, TNFα, and IL-17 A in the serum of male offspring. Our work demonstrates that perinatal exposure to a low dose of Pb or the BDE209/Pb mixture, although it did not induce typical ASD-like symptoms, elicited restricted, repetitive patterns of behavior and affected learning in male offspring. In addition, the synergistic increase in the systemic inflammatory response in the BDE209/Pb co-exposure group underscores the importance of evaluating chemical mixtures in disease onset.

Interactions of Cd, Cr, Pb, Ni, and Hg in their effects on activated sludge bacteria by using two analytical methods

Since trace metals rarely appear singly in industrial effluents, it is a major challenge to address combined effects of such toxicants on biological units of wastewater treatment plants. The aim of this study was interaction assessment of Cd, Cr, Pb, Ni, and Hg in their effects on activated sludge bacteria using analytical methods. Two mathematical models were used to determine the effect of binary mixtures of Hg, Cd, Cr, Pb, and Ni on activated sludge bacteria using a dehydrogenase enzyme assay. Calculated EC50 values were compared to experimentally observed values of mixtures. Interactive effects were counted to be antagonistic for Hg and Cd, Cd and Pb, Cd and Ni, and Cr and Pb, synergistic for Cd and Cr and Hg and Cr, and additive for other binary mixtures. Maximum toxicity was related to Hg and Cr, Cd and Cr, and Hg and Cd. Physicochemical monitoring of single metals may underestimate hazards arising from these pollutants in environmental samples. Therefore, any possible interaction between metals in such environments should be considered when establishing environmental safety standards.

Toxic Effect of Acute Cadmium and Lead Exposure in Rat Blood, Liver, and Kidney.

Background: Cadmium and lead are widespread and non-biodegradable pollutants of great concern to human health. In real life scenarios, we are exposed to mixtures of chemicals rather than single chemicals, and it is therefore of paramount importance to assess their toxicity. In this study, we investigated the toxicity of Cd and Pb alone and as a mixture in an animal model of acute exposure. Methods: Experimental groups received a single treatment of aqueous solution of Cd-chloride (15 and 30 mg/kg body weight (b.w.) and Pb-acetate (150 mg/kg b.w.), while the mixture group received 15 mg Cd/kg b.w. and 150 mg Pb/kg b.w. Toxic effects of individual metals and their mixture were investigated on hematological and biochemical parameters, and the redox status in the plasma, liver, and kidneys of treated Wistar rats. Results: Tissue-specific changes were recorded in various parameters of oxidative damage, while the accumulation of metals in tissues accompanied the disturbances of both hematological and biochemical parameters. It was observed that the level of toxic metals in tissues had a different distribution pattern after mixture and single exposure. Conclusions: Comprehensive observations suggest that exposure to Cd and Pb mixtures produces more pronounced effects compared to the response observed after exposure to single metal solutions. However, further research is needed to confirm toxicokinetic or toxicodynamic interactions between these two toxic metals in the organisms.

Addition of commercial probiotic in a biofloc shrimp farm of Litopenaeus vannamei during the nursery phase: Effect on bacterial diversity using massive sequencing 16S rRNA

The aim of this study was to describe the effect of the addition of commercial probiotics on the bacterial diversity in biofloc generated in a commercial farm of whiteleg shrimp Litopenaeus vannamei. The experiment consisted of a simple random design with three treatments by triplicate (two commercial probiotics: PA and PB, and one control, C). The PA was composed by a mixture (50:50) of Efinol PT and Mix Laboratory Robles; the second, coded as PB was composed by the mixture (50:50) of Epicin Ponds and Epicin Hatcheries. The control treatment, coded as C (natural endemic microbial consortium), consisted of the traditional biofloc system without probiotic application. The samples were obtained during tree periods of the shrimp nursery (beginning, medium and final). The abundance and diversity indexes (alpha, beta and gamma) were calculated. The shrimp productive parameters were determined. The ponds receiving the PA mixture registered 22 phyla, being Proteobacteria (49.99–53.66%), Planctomycetes (9.62–18%) and Bacteroidetes (11.41–29.66%) the most abundat. The ponds receiving the PB mixture, registered 19 phyla, and Proteobacteria (49.09–60.81%), Bacteroidetes (8.18–26.56%) and Planctomycetes (6.38–25.05%) were the most abundant. The control ponds had 19 phyla, and Proteobacteria (43.15–73.88%), Bacteroidetes (16.29–25.56%) and Planctomycetes (5.03–9.37%) registered the highest abundance. During the tree sampling periods, the Shannon index (alpha diversity) varied from 1.54–1.40 in PA; 1.34 to 1.41 in PB and 0.88 to 1.59 in C. The beta diversity indicated 86% of similarity among PA-C; and 90% among PB-C. At the end of the study, the gamma diversity in bioflocs depends 96% of alpha diversity and 3.70% of beta diversity. The autochthonous bacteria had the greatest influence on the diversity. The productive parameters did not show significant differences among treatments (P < 0.05).

Effects of combined arsenic and lead exposure on the brain monoaminergic system and behavioral functions in rats: Reversal effect of MiADMSA.

In this study, we evaluated the therapeutic efficacy of monoisoamyldimercaptosuccinic acid (MiADMSA) against individual and combined effects of arsenic (As) and lead (Pb) on the monoaminergic system and behavioral functions in rats. Pregnant rats were exposed to sodium metaarsenite (50 ppm) and lead acetate (0.2%) individually and in combination (As = 25 ppm + Pb = 0.1%) via drinking water from gestation day (GD) 6 to postnatal day (PND) 21. MiADMSA (50 mg/kg body weight) was given orally through gavage for 3 consecutive days to pups from PND 18 to PND 20. The results showed increases in synaptosomal epinephrine, dopamine, and norepinephrine levels with individual metal exposures and decreases with combined exposure to As and Pb in the cortex, cerebellum, and hippocampus in PND 21, PND 28, and 3 months age-group rats. We found decreased activity of mitochondrial monoamine oxidase in the selected brain regions following individual and combined exposures to Pb and As. In addition, rats treated with Pb and As alone or in combination showed significant deficits in open-field behavior, grip strength, locomotor activity, and exploratory behavior at PND 28 and 3 months of age. However, MiADMSA administration showed reversal effects against the As- and/or Pb-induced impairments in the monoaminergic system as well as in behavioral functions of rats. Our data demonstrated that the mixture of Pb and As induced synergistic toxicity to developing brain leading to impairments in neurobehavioral functions and also suggest therapeutic efficacy of MiADMSA against Pb- and/or As-induced developmental neurotoxicity.

Sustainability of Asphalt Paving Materials Containing Different Waste Materials

Generating recycled tires, disposable plastic bottles and waste engine oil are important problem in Iraq and there is need to solve it. The waste materials can be considered as alternative materials in road pavement technology and the using of these materials would be a solution to converse the environment from pollution in one hand and modifying the asphalt paving materials on the other hand. The two waste materials (recycled tire rubber and plastic bottles) have been evaluated as supplementary materials by with (3, 6, 9 and 12) % by total weight of aggregate retained on 2.36 mm sieve. The waste engine oil was used as an asphalt cement modifier and it was added as partial replacement of asphalt content by with (5, 10 and 15) % by weight of asphalt. This experimental work aimed to use Marshall properties, indirect tensile strength, and immersion-compression and wheel track tests to determine the influence of different waste materials on the performance of compacted asphalt paving materials of highways. The study concluded that the 12%PB mixtures seem to produce a reduction in the density and rut depth, an increase in air void, VMA, Marshall stability and indirect tensile strength. The recycled tires with 9% by total weight of aggregate retained on (2.36mm) sieve exhibited high resistance to water damage. The indirect tensile strengths of the asphalt mixtures incorporated waste oil engine were lower than those of the control mix and these modified mixtures have a good resistance to moisture damage.

The impact of temperature on metal mixture stress: Sublethal effects on the freshwater isopod Asellus aquaticus

Chemical and natural factors have been demonstrated to interact and potentially change the toxicity of the individual stressors. Yet, while there exists a multitude of papers studying the temperature-dependent toxicity of single chemicals, little research exists on the impact of temperature on chemical mixtures. This paper investigates the effect of temperature on environmentally-relevant mixtures of Cd, Cu and Pb. We linked the effects on respiration, growth, feeding rate and activity of Asellus aquaticus to the free ion activities, as a measure for the bioavailability of the metals, and the body concentrations. We observed interactions of temperature and metal body concentrations on all sublethal endpoints, except activity. Mixture effects on accumulation and feeding rate were observed as well and even an interaction between metal body burden, mixture and temperature treatment was revealed for the feeding rate of Pb exposed isopods. This research adds to a growing body of evidence that the current chemical-based monitoring is insufficient to estimate chemical toxicity in aquatic ecosystems and must, therefore, be complemented with effect-based tools.

Characteristics and fabrication of piezoelectric GFRP using smart resin prepreg for detecting impact signals

To develop a composite that also functions as an impact sensor, a piezoelectric glass fiber-reinforced polymer (GFRP) was fabricated using a mixture of Pb(Ni1/3Nb2/3)O3-Pb(Zr, Ti)O3 (PNN-PZT) piezoelectric powder and epoxy as a smart resin. Prepreg sheets were prepared by impregnating glass fiber with the smart resin and the specimen was fabricated by autoclave molding. To utilize the composite as a sensor for detecting impacts, electrodes were added to the two sides of the composite, and the specimen was poled briefly at room temperature to activate its piezoelectric properties. A calibrated and instrumented impact test was conducted to demonstrate impact response and measure the sensitivity; a signal processing device was developed that matched the high impedance of the piezoelectric GFRP. The sensitivity of the piezoelectric GFRP sensor was measured by comparing the impact force signals from an impact hammer with the corresponding output voltage from the sensor. The threshold for detection of impacts was below 15 N. The tests confirmed that the piezoelectric GFRP itself could be utilized as an impact sensor.

Combination of phenobarbital with phenytoin and pregabalin produces synergy in the mouse tonic-clonic seizure model: An isobolographic analysis

AimsDespite many antiepileptic drugs (AEDs) are available to treat epilepsy, there is still about 30% of epilepsy patients inadequately treated with these AEDs. For these patients, polytherapy with two or three AEDs to fully control their seizure attacks is recommended. Unfortunately, polytherapy is always associated with drug interactions, whose nature may be beneficial, neutral or unfavorable. To determine a type of interaction for the combination of three AEDs (i.e., phenobarbital [PB], phenytoin [PHT] and pregabalin [PGB]) at the fixed-ratio of 1:1:1, we used a model of tonic-clonic seizures in male albino Swiss mice. Materials and methodTonic-clonic seizures in mice were evoked by a current (sine-wave, 25 mA, 500 V, 0.2 s stimulus duration) delivered via auricular electrodes. The anticonvulsant effects of the three-drug combination (PB, PHT and PGB) in terms of suppression of tonic-clonic seizures in mice were assessed with type I isobolographic analysis. Potential acute side effects for the mixture of PB, PHT and PGB along with total brain concentrations of the AEDs were determined to confirm pharmacodynamic nature of observed interaction. ResultsThe three-drug combination of PB, PHT and PGB (at the fixed-ratio of 1:1:1) exerted synergistic interaction (at P < 0.01) in the mouse model of tonic-clonic seizures. The combination of PB, PHT and PGB did not produce any side effects in experimental animals, when measuring long-term memory, muscular strength and motor coordination. The measurement of total brain concentrations of PB, PHT and PGB was conducted to confirm that none of the three AEDs significantly influenced total brain concentrations (pharmacokinetic profiles) of the other co-administered AEDs in mice. ConclusionsThe synergistic pharmacodynamic interaction for the combination of PB, PHT and PGB observed in this preclinical study can be translated into clinical settings and this favorable AED combination is worthy of being recommended to some patients with refractory epilepsy.

Multivariate optimization and characterization of simultaneous removal of binary mixture of Cu(II) and Pb(II) using Fe3O4@MoS2 nanoparticles

AbstractIn this study, a facile hydrothermal method was used for the synthesis of Fe3O4@MoS2 magnetic nanoparticles. Then, this compound was used as an efficient adsorbent for the simultaneous removal of Cu(II) and Pb(II) ions from water. The prepared nanoparticles were characterized by scanning electron microscopy, X‐ray diffraction, vibrating sample magnetometer, and Fourier transform infrared spectroscopy. In addition, the effect of operational parameters on the adsorption process, such as initial pH, the concentration of metal ions, and sorbent mass, was investigated. The results of response surface methodology, obtained from Box‐Behnken design, was used to optimize the removal percent (%R) of Cu(II) and Pb(II). The effect of the different variables and their interactions was displayed by a regression model. A good agreement was seen between the proposed quadratic model resulting from Box‐Behnken design approach and the experimental data. According to the obtained results, the optimized conditions for the removal of metal ions were as follows: pH = 3, sorbent dose = 0.05 g, CPb (initial Pb(II) concentration) = 240.70 mg/L, and CCu (initial Cu(II) concentration) = 198 mg/L. The adsorption of both Freundlich and Langmuir isotherm models and pseudo‐second‐order kinetic model described the adsorption process well (R2 &gt; 0.99). The obtained amounts of the thermodynamic parameters, such as ∆G°, ∆S°, and ∆H°, have proved that the adsorption of Pb(II) and Cu(II) ions on the surface of Fe3O4@MoS2 nanoparticles is spontaneous, feasible, and endothermic in nature.

Combined effects of metal mixtures and predator stress on the freshwater isopod Asellus aquaticus

Biotic stressors have been demonstrated to change the toxicity of pollutants. While the combined effects of predator cues and pesticides are well documented, the interaction of predator stress with metals is a topic that has remained largely unexplored. In this laboratory experiment, the freshwater isopod Asellus aquaticus is exposed to predator cues and metal mixtures of Cd, Cu and Pb. We examined the effects on growth, respiration and, as behavioral parameters, feeding rate and activity. These were linked to the free ion activities (FIAs) in the water and the metal body concentrations. The findings reveal that Cu accumulation significantly influenced the growth rate, the feeding rate and the activity of isopods exposed to predator stress. Furthermore, we found a concentration-dependent interaction of the Cd + Pb mixtures on the feeding rate and a lower feeding rate for Cd and Pb predator exposed asellids. As several interactions were found between metals and predator stress, it demonstrates the importance of investigating how organisms and whole ecosystems respond to multiple stressors. A better understanding of these interactions will undoubtedly improve risk assessment and management.

Valorization of Adenanthera pavonina seeds as a potential biosorbent for lead and cadmium removal from single and binary contaminated system

This study investigated the biosorption of Pb (II) and Cd (II) on powdered seeds of Adenanthera pavonina from single and binary heavy metal solutions. The adsorption capacity of the metal ions was studied as a function of pH, adsorbent dose, initial metal ion concentration, and contact time. In the single heavy metal system, maximum removal of Pb (II) and Cd (II) were achieved at pH 4 and 6, respectively, while the equilibrium was attained at a contact duration of 35 min at a constant dose of 5 g L−1 was maintained for both Pb (II) and Cd (II). Further, the kinetic study revealed that the biosorption process was best described by the second-order kinetic model. In the competitive biosorption of binary mixtures of Pb (II) and Cd (II) were studied in terms of percentage removal of metal ions, adsorption capacity and equilibrium sorption isotherm. The percentage removal of metal ions in binary solutions was suppressed in presence of the other competitive metal ion. Field emission scanning electron microscopy integrated with energy dispersive X-ray spectroscopy of the biomass before (control) and after (metal loaded biomass) the biosoption process, confirmed the presence of respective heavy metal on to the biomass. Fourier transmission infrared spectroscopy spectra supported the activity of hydroxyl, amines, amides, and carboxyl groups in uptake of both heavy metal ions.