Adsorption Behavior Of Lead Research Articles

Adsorption behavior of lead, cadmium, and arsenic on manganese-modified biochar: competition and promotion.

Biochar adsorption of heavy metals has been a research hotspot, yet there has been limited reports on the effect of heavy metal interactions on adsorption efficiency in complex systems. In this study, the adsorbent was prepared by pyrolysis of rice straw loaded with manganese (BC-Mn). The interactions of Pb, Cd and As adsorption on BC-Mn were systematically studied. The results of the adsorption isotherms for the binary metal system revealed a competitive adsorption between Pb and Cd, resulting in decreased Pb (from 214.38mg/g to 148.20mg/g) and Cd (from 165.73mg/g to 92.11mg/g). A notable promotion occurred between As and Cd, showing an increase from 234.93mg/g to 305.00mg/g for As and 165.73mg/g to 313.94mg/g for Cd. In the ternary metal system, Pb inhibition did not counteract the promotion of Cd and As. Furthermore, the Langmuir isotherm effectively described BC-Mn's adsorption process in monometallic, binary, and ternary metal systems (R2 > 0.9294). Zeta and FTIR analyses revealed simultaneous competition between Pb and Cd for adsorption on BC-Mn's -OH sites. XPS analysis revealed that As adsorption by BC-Mn facilitated the conversion of MnO2 and MnO to MnOOH, resulting in increased hydroxyl radical production on BC-Mn's surface. Simultaneously, Cd combined with the adsorbed As to form ternary Cd-As-Mn complexes, which expedited the removal of Cd. These results help to provide theoretical support as well as technical support for the treatment of Pb-Cd-As contaminated wastewater.

Comparison of lead adsorption on the aged conventional microplastics, biodegradable microplastics and environmentally-relevant tire wear particles

In this study, the adsorption behavior of lead (Pb(II)) onto environmentally-relevant tire wear particles (TWP) gained by natural weathering and mechanical abrasion, ultraviolet-aged polylactic acid microplastics (UV-PLA), and ultraviolet-aged polystyrene microplastics (UV-PS) was compared to investigate the difference of representative microplastics between the adsorption capacity and mechanism. Our results indicated that the aging processes significantly improved the adsorption capacity to Pb(II), and TWP had the highest adsorption amount, followed the order by UV-PLA, UV-PS, PLA and PS. Electrostatic interaction and complexation of oxygen-containing functional groups played crucial roles in the adsorption of Pb(II) onto UV-PLA, the adsorption mechanisms of UV-PS involved electrostatic interaction, complexation and cation-π interaction, while adsorption of TWP was might dominated by the complexation of surface functional groups and properties of the complex rubber co-polymer. Interestingly, the low concentration of humic acid (HA) most significantly improved adsorption capacity of aged microplastics to Pb(II), otherwise it was severely suppressed at higher concentration of HA. Besides, the adsorption behavior of different binary systems between aged microplastics and suspended sediment to Pb(II) had complicated synergistic or suppressive effects with a concentration-dependent and polymer-dependent trend. Furthermore, UV-PLA had the far stronger desorption ability of Pb(II) than that of TWP and UV-PS, suggesting that metal-contaminated biodegradable microplastics posed the higher ecological risks to aquatic organisms. Desorption quantity and rates of Pb(II) from aged microplastics in the simulated sediment system were generally higher than those in turbulent water column. Collectively, these findings provide a wide insight into adsorption capacity and mechanisms of metal ions on the representative aged microplastics and the desorption behavior in complex aquatic environments.

Adsorption of lead(II) and chromium(VI) from aqueous environment onto metal-organic framework MIL-100(Fe): Synthesis, kinetics, equilibrium and thermodynamics

In present research, MIL-100(Fe) was efficiently synthesized by hydrothermal strategy applying HF as mineralizing agent and its ability was examined for lead(II) and chromium(VI) adsorption from an aqueous environment. Structural, chemical and morphological properties of the synthesized MOF were specified by different experimental techniques including XRD, FTIR, SEM, EDS and adsorption isotherms of N2 at 77 ​K (BET). D-spacing was measured with Debye–Scherrer’s formula as 7.98 ​Å. Also, the analyses confirmed relatively high BET surface area (1843.9 ​m2 ​g−1) and an octahedral-shaped structure for MIL-100(Fe) synthesized. Additionally, the adsorption behavior of lead(II) and chromium(VI) onto the MIL-100(Fe) was investigated using kinetics, equilibrium and thermodynamic parameters. Equilibrium analysis exhibited that the maximum uptake capacity for lead(II) was 23.46 ​mg ​g−1 based on sips model and for chromium(VI) was 30.45 ​mg ​g−1 ​by Langmuir isotherm. The sorption kinetics of lead(II) followed the pseudo 1st order model, while for chromium(VI) followed both pseudo 1st order and pseudo 2nd order models. Thermodynamic conclusions indicated a non-spontaneous nature for the sorption of each two metals and an exothermic reaction for lead(II) and endothermic nature for chromium(VI). Meanwhile, chemical ion-exchange and physisorption were distinguished as dominant adsorption mechanisms for lead(II) and chromium(VI), respectively.

X-Ray Absorption Spectroscopy Analysis of Lead Species Adsorbed on Various Oxides from High pH Solution

Lead dissolved in water must be removed in order not to cause diseases, especially from high pH aqueous solution. Various oxides having high specific surface area are often applied to remove lead in water media. To improve removal ability for lead species, it is necessary to understand the adsorbed structure of lead species on oxides. At first, the adsorption behavior of lead from high pH solution in the presence of Ca2+ and Na+ was compared. Lead and calcium species were adsorbed up to the monolayer, and the adsorption isotherm was analyzed as Langmuir-type adsorption. In the presence of Ca2+, the amount of removed lead was reduced. To clarify this influence of Ca2+, X-ray absorption spectroscopy was adopted. It was for the first time revealed that lead species at pH > 12 and pH < 10.5 differed, and that lead species adsorbed on various oxides had a similar structure.

Pb(II) uptake onto nylon microplastics: Interaction mechanism and adsorption performance

Both heavy metals and microplastic pollutants are ubiquitous in the aquatic environment. The uptake of lead(II) ions from aqueous solutions onto aged nylon microplastics was investigated as a function of pH, contact time, temperature, supporting electrolyte concentration and fulvic acid concentration in batch studies. The effect of surface properties on the adsorption behavior of lead(II) was investigated with scanning electron microscope equipped with the energy dispersive X-ray spectroscope (SEM-EDAX), Fourier transform-infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and differential scanning calorimetric (DSC). The adsorption kinetics conformed to the pseudo-second order equation, Elovich equation and intraparticle diffusion model well. The experimental data of the adsorption process was fitted to the Langmuir and Freundlich adsorption isotherms and the parameters were estimated. The lead(II) uptake on aged nylon microplastics was spontaneous and endothermic in nature. The lead(II) adsorption was significantly dependent on the sodium chloride concentrations, initial solution pH and fulvic acid concentrations. Results of this study highlight the importance of surface carboxyl function group of aged nylon microplastics in controlling lead(II) adsorption.

Adsorption of lead on clay-CNT nanocomposite in aqueous media by UV-Vis-spectrophotometer: kinetics and thermodynamic studies

The present study describes the adsorption of lead on novel Clay-CNT nanocomposite for removal of trace levels of lead (≤ 50 mg L−1) from water. The effect of CNT loading levels and adsorption behavior of lead onto nanocomposite has been explored. The sorption percentage of lead increased from 52 to 76.7% on decreasing of the mass percent of CNT from 15 to 3% in clay-CNT nanocomposite (CCN). Equilibrium time, pH, temperature, initial lead concentration, and amount of adsorbent correlated effectively with lead adsorption. The lead removal efficiency of CCN is about 88–90% at pH 6.0, and at same reaction conditions the adsorption capacity is 9.43 mg g−1. The kinetic studies shows that lead adsorption onto synthesized CCN equilibrates within 120 min. The enthalpy change of lead adsorption ranged between − 77.92 to 20.04 KJ mol−1 with entropy change between − 252.74 to 59.05 J mol−1 K−1 for solution containing lead concentration between 5 and 20 mg L−1 indicated an exothermic and spontaneous adsorption process. This study focuses on the application of kaolinite-CNT nanocomposite as novel adsorbent for removal of trace levels of lead (≤ 15 mg L−1) from water. It is an economically feasible material since only 3% CNT is used in clay matrix, which enhances the adsorption properties of clay significantly.

Adsorption behavior of lead on aquatic sediments contaminated with cerium dioxide nanoparticles

Aquatic sediments serve as an important sink for engineered nanomaterials (ENMs), such as metal oxide nanoparticles (MeO NPs) and carbon nanotubes (CNTs). Owing to their remarkable properties, ENMs demonstrate significant potential to disturb the adsorption behavior of other contaminants in aquatic sediments, thereby altering the bioavailability and toxicity of these contaminants. Thus far, most studies have investigated the effect of CNTs on the adsorption of other contaminants on sediments. Cerium dioxide nanoparticles (CeO2 NPs), as one of the important MeO NPs, are also inevitably discharged into aquatic sediments because of their widespread use. In this study, we investigated the adsorption behavior of Pb2+ on sediments spiked with CeO2 NPs at a weight ratio of 5.0%. The results showed that the adsorption rates at three stages occurring during adsorption clearly increase for sediments contaminated with CeO2 NPs. Moreover, the results obtained from the adsorption isotherms indicated that the Langmuir isotherm model best fits the isotherm data for both sediments and those contaminated with CeO2 NPs. After spiking the sediments with CeO2 NPs, the theoretical maximum monolayer adsorption capacity (Qmax) for Pb2+ increased from 4.433 to 4.995 mg/g and the Langmuir isotherm coefficient (KL) decreased from 8.813 to 7.730 L/g. The effects of CeO2 NPs on the surface charge and pore surface properties of sediments were also studied as these properties affect the adsorption of several chemicals in sediments. The results showed that pHzpc, SBET, Sext, and average pore size of sediments clearly decrease for sediments contaminated with CeO2 NPs. Hence, the strong adsorption capacity of CeO2 NPs and the changes of sediment surface charge and pore surface properties caused by CeO2 NPs are important factors affecting the adsorption behavior of Pb2+. The potential risk of Pb2+ in aquatic environment may increase with CeO2 NPs buried in sediments.

Decoration of electrospun polyacrylonitrile nanofibers with ZnO nanoparticles and their application for removal of Pb ions from waste water

The adsorption behavior of lead (II) from aqueous solutions utilizing ZnO/polyacrylonitrile (PAN) nanofibers was studied. ZnO/PAN nanofibers were prepared by electrospinning method. The changes of the parameters of adsorbent amount, pH, contact time, and temperature were tested in the adsorption experiments. The adsorption was well described by the Langmuir adsorption isotherm model. The thermodynamic parameters indicate that the adsorption process is exothermic. The dynamic behavior of the lead (II) ions adsorption by PAN/ZnO nanofibers was well described by the pseudo-second-order kinetic model. The adsorbent can be regenerated by suitable desorption processes for multiple uses without significant loss of its adsorption capacity.

Adsorption Behavior of Lead, Cadmium and Nickel on some Calcareous Soils

THERE are many environmental factors that influence the mobility …. and bioavailability behavior of some heavy metals in soils. One of these factors is the content and form of calcium carbonate in soils.

Synthesis of TiO2/polyacrylonitrile nanofibers composite and its application to lead ions removal from waste waters

The adsorption behavior of lead(II) from aqueous solutions utilizing TiO2/polyacrylonitrile (PAN) nanofibers was studied. TiO2/PAN nanofibers were prepared by electrospinning method and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscope. These data were utilized to show nanofibers and TiO2 nanoparticles morphology and existence of TiO2 in nanofibers web. The results show that the size of nanoparticles is about 70 nm and the fibers diameters is in the range of 1–2 μm. The changes in the parameters of adsorbent dosage, pH, contact time, TiO2 concentration, and temperature were tested in the adsorption experiments. The adsorption was well described by the Langmuir adsorption isotherm model. The thermodynamic parameters indicate that the adsorption process is spontaneous and endothermic. The pseudo-first-order kinetic model describes the dynamic behavior for the adsorption of lead(II) ions onto PAN/TiO2 nanofibers.

Adsorption behavior of lead onto a new class of functionalized silica gel

In this study the surface of silica gel was functionalized with 2-thiophenecarbonyl, 2-furoyl and l-proline. The synthesized materials were characterized by fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM) with energy dispersive X-ray analyzer (EDX). Batch adsorption studies were carried out to analyze the adsorption of the lead ion from aqueous solution. The factors influencing % adsorption of Pb(II) onto the silica gel and functionalized silica gel such as initial pH value of the Pb(II) ion solution, adsorbent dose, initial Pb(II) ion concentration, contact time and temperature were investigated. Langmuir and Freundlich isotherm models were used to determine the isotherm parameters associated with the adsorption process. Kinetic data were analyzed considering pseudo-first order, pseudo-second order and intraparticle diffusion approaches. The latter two mechanisms seem to be significant in the rate-controlling step. Negative values of Gibb's free energy change (ΔG°) showed that the adsorption was feasible and spontaneous and negative values of enthalpy change (ΔH°) confirmed exothermic adsorption.

Adsorption Behavior of Lead(Ⅱ) by Crosslinked Polyacrylonitrile and Its Application in Trace Analysis

采用火焰原子吸收光谱法（FAAS）研究了交联聚丙烯腈螯合树脂对环境样品中Pb2＋的吸附分离/富集行为,并考察了共存离子的干扰。结果表明,该树脂对Pb2＋的吸附率在溶液pH=5.4、静态吸附时间1.5 h时室温下可达90%。在最佳吸附条件下,树脂对单一Pb2＋的饱和吸附容量可达49.6 mg/g。以0.1 mol/L盐酸溶液作为解吸剂,可将吸附在树脂上的Pb2＋定量洗脱,富集倍数和解吸率可分别达到50和97%。富集50倍后,方法的检出限（3σ10）为5.3μg/L;相对标准偏差（RSD）为2.1%;加标回收率为92.9%～97.6%。

Acidic polysaccharide gels for selective adsorption of lead (II) ion

The adsorption behavior of lead (II), zinc (II) and copper (II) on crosslinked pectic and alginic acids, and their amide derivatives form has been investigated. The selectivity order for metal ion uptake is lead (II) > copper (II) > zinc (II). The nature of such acidic polysaccharides for the removal of lead (II) ion was examined through batch wise tests and column tests and compared with that for the commercially available weakly acidic cation exchange DIAION WK resins. The experimental results revealed that chemically modified acidic polysaccharides exhibit much better separation performance compared to the latter, which suggests a high possibility of their applications in the practical separation and purification of lead (II) ion.

Adsorption Behavior of Lead (II) in Water by Means of Fern Plant Paper

Adsorption Behavior of Lead (II) in Water by Means of Fern Plant Paper