Efficient Removal Of Pb Research Articles

Efficient Removal of Pb(II) and Cd(II) Using NH2-Functionalized Zr-MOFs via Rapid Microwave-Promoted Synthesis

Heavy metal ions of Pb(II) and Cd(II) have become the global health and environmental concerns. NH2-functionalized Zr-MOFs were prepared via a rapid microwave-promoted synthesis and first used in the adsorptive removal of both Pb(II) and Cd(II). The nanosized (<100 nm) Zr-MOFs had an XRD pattern of UiO-66-NH2. Effects of adsorption time, temperature, pH, and initial ions concentration were studied on the adsorption of Pb(II) and Cd(II) onto the Zr-MOFs. The absorption results showed that the removal of Pb(II) was 99.95% after 120 min at temperature of 30 °C and pH of 6 with an initial concentration of 10 mg·L–1. And the adsorption capacity of Cd(II) achieved 177.35 mg·g–1 at an initial concentration of 40 mg·L–1. The adsorption fit the pseudo second-order kinetic model well and the mechanism was confirmed mainly as a coordination interaction between the amino group (−NH2) and Pb(II) or Cd(II). The NH2-functionalized Zr-MOFs have been proven to show good performance in the removal of heavy metal ions as an...

Efficient removal of Pb(II) by amine functionalized porous organic polymer through post-synthetic modification

Abstract Porous organic polymers (POPs), a new class of porous materials constructed by organic molecular building blocks, have attracted much attention. To design POPs with both good porosity and specific-task functionalization is still a critical challenge. In this work, using a simple Friedel-Crafts one-step reaction, one of the most common organic compound methylbenzene monomers were polymerized through the cross-linker formaldehyde dimethyl acetal (FDA) to produce a cost-effective non-functionalized porous polymer (POP-CH 3 ). Moreover, amine groups were further incorporated into the network by the post-synthetic modification method. The resulted porous polymer POP-NH 2 presented highly effective in removing Pb(II) from aqueous solution. The maximum Pb(II) adsorption capacity, q max , evaluated from the Langmuir model was 523.6 mg g −1 . The combination of FT-IR experimental results and the theoretical quantum calculations illustrated that the amine groups ( NH 2 ) can easily form coordination complexes with Pb(II), which were responsible for efficient adsorption. The generated POP-NH 2 could be regenerated effectively and recycled at least four times without significant loss of adsorption efficiency. Hence, the outstanding Pb(II) adsorption capacity, excellent reusability as well as low cost of synthesis create potential polymer POP-NH 2 to be an attractive adsorbent for removing toxic metal ions from aqueous solution.

Removal efficiency of Pb(II), Zn(II), Cd(II) and Cu(II) from aqueous solution and natural water by ketoenol–pyrazole receptor functionalized silica hybrid adsorbent

ABSTRACTIn this study, we reported an efficient, alternative, and low-cost adsorbent for the efficient removal of Pb(II), Zn(II), Cd(II) and Cu(II) from water. The new hybrid material has been prepared by immobilizing a conjugated system (2Z)-1-(1,5-dimethyl-1H-pyrazol-3-yl)-3-hydroxybut-2-en-1-one on silica gel previously doped with 3-aminopropyltrimethoxysilane. The formed surface (SiNPz) was perfectly analyzed. Adsorption studies have demonstrated the ability to highlight the surface designed for efficient removal of above toxic metals from aqueous solutions using FAAS. The new material was used for the extraction of metals from natural water and showed efficiency results for toxic heavy metals.

Efficient Removal of Pb(II) from Aqueous Solution by Modified Montmorillonite/Carbon Composite: Equilibrium, Kinetics, and Thermodynamics

In the present study, a new type of montmorillonite/carbon (MMT/C) adsorbent has been prepared by a one-pot hydrothermal carbonization process. The MMT/C composite was further modified to obtain functionalized MMT/C, i.e., hydroxylated MMT/C, carboxylated MMT/C, and aminated MMT/C. The prepared MMT/C-based sorbents were systematically characterized by X-ray diffraction (XRD), specific surface area, zeta potential, and scanning electron microscopy (SEM). Their adsorption capacity was evaluated by the removal of aqueous Pb(II) ions, following the order carboxylated MMT/C > hydroxylated MMT/C > aminated MMT/C > MMT/C. Moreover, the influential factors for Pb(II) removal by carboxylated MMT/C composites, such as pH, temperature, and initial concentration, were thoroughly explored. The adsorption capacity increases significantly when the pH increases from 2.0 to 5.0 but with minor change beyond. The maximum adsorption capacities of MMT/C–COOH toward Pb(II) are 247.85 mg g–1. The complexation of surface groups ...

Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO2 nanoparticles from aqueous media

Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51±3.8nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, 1H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box–Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r2) and non-linear Chi-square (χ2) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption–desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters.

Synthesis of magnetic graphene nanocomposites decorated with ionic liquids for fast lead ion removal

Seeking highly-efficient, low-cost and robust methods to remove metal ions from aqueous solutions is very much in demand. Here, we developed a novel magnetic composite bio-adsorbent, graphene oxide and magnetic chitosan-ionic liquids (GOMCS-ILs), for removing Pb(II) from water. This was the first time to combine ionic liquids and graphene oxide and magnetic chitosan, and apply to the adsorption of metal ions. The addition of ionic liquids can not only improve the dispersivity of the adsorbent, but also increase the adsorption sites. The characteristic result of FTIR, SEM, and XRD showed that GOMCS-ILs were prepared with large surface area and good magnetic responsiveness. The influence of various analytical parameters on the adsorption of Pb(II) such as pH, contact time, and initial ion concentration were studied in detail. The adsorption followed a pseudo second order kinetics. The equilibrium adsorption was well-described by the Langmuir isotherm model and the maximum adsorption capacity was to be 85mgg−1. Moreover, the GOMCS-ILs could be repeatedly used by simple treatment without obvious structure and performance degradation. These results demonstrated the potential applications of GOMCS-ILs microspheres in efficient removal of Pb(II) from wastewater and deep-purification of polluted water.

Adsorption of Pb(II) Ions on Sulfuric Acid TreatedLeucaena leucocephalaLeaf Powder

Sulfuric acid treated Petai belalang ( Leucaena leucocephala ) leaf powder (SLLP) was used as an adsorbent for Pb(II) ions removal. The experimental adsorption parameters investigated include pH, dosage and initial Pb(II) concentration. Pb(II) removal was more favored at a higher adsorbent dosage, pH and temperature. Adsorption kinetics conformed to the pseudo-second order model while Langmuir isotherm model recorded the value of maximum adsorption capacity (q max ) of 222 mg/g. The major functional groups involved in the adsorption process were identified as hydroxyl, amino and ether as revealed by the FTIR analysis. The prepared adsorbent demonstrated a potential application for efficient removal of Pb(II) ions from industrial wastewater.

Lead coprecipitation with iron oxyhydroxide nano-particles

Pb 2+ and Fe 3+ coprecipitation was studied with sorption edge measurements, desorption experiments, sorbent aging, High Resolution Transmission and Analytical Electron Microscopy (HR TEM–AEM), and geochemical modeling. Companion adsorption experiments were also conducted for comparison. The macroscopic chemical and near atomic scale HRTEM data supplemented our molecule scale analysis with EXAFS ( Kelly et al., 2008). Coprecipitation of Pb 2+ with ferric oxyhydroxides occurred at ∼pH 4 and is more efficient than adsorption in removing Pb 2+ from aqueous solutions at similar sorbate/sorbent ratios and pH. X-ray Diffraction (XRD) shows peaks of lepidocrocite and two additional broad peaks similar to fine particles of 2-line ferrihydrite (2LFh). HRTEM of the Pb–Fe coprecipitates shows a mixture of 2–6 nm diameter spheres and 8–20 by 200–300 nm needles, both uniformly distributed with Pb 2+. Geochemical modeling shows that surface complexation models fit the experimental data of low Pb:Fe ratios when a high site density is used. Desorption experiments show that more Pb 2+ was released from loaded sorbents collected from adsorption experiments than from Pb to Fe coprecipitates at dilute EDTA concentrations. Desorbed Pb 2+ versus dissolved Fe 3+ data show a linear relationship for coprecipitation (CPT) desorption experiments but a parabolic relationship for adsorption (ADS) experiments. Based on these results, we hypothesize that Pb 2+ was first adsorbed onto the nanometer-sized, metastable, iron oxyhydroxide polymers of 2LFh with domain size of 2–3 nm. As these nano-particles assembled into larger particles, some Pb 2+ was trapped in the iron oxyhydroxide structure and re-arranged to form solid solutions. Therefore, the CPT contact method produced more efficient removal of Pb 2+ than the adsorption contact method, and Pb 2+ bound in CPT solids represent a more stable sequestration of Pb 2+ in the environment than Pb 2+ adsorbed on iron oxyhydroxide surfaces.

The influence of ph and adsorbent concentration on adsorption of lead and zinc on a natural goethite

Adsorption characteristics of Pb and Cd were conducted on a natural goethite from Kaduna (Niperia) and compared same with a synthetic goethite. The adsorption data was fitted into Langmuir model which gave Langmuir constants k and Xm for Pb and Cd as 4.99 & 2.40 and1.43 & 1.05 respectively. The adsorption behavior was essentially the same, although, synthetic goethite sorbed a little more metal ion than the natural goethite. This was attributed to the higher proportion of goethite in synthetic than natural goethite per unit mass of sample rather than greater chemical reactivity of the synthetic goethite. The influence of variable pH and adsorbent concentrations on the sorption of Pb and Cd by the natural goethite was studied. Sorption efficiencywas greatly governed by pH with nearly 100% adsorption of Pb occurring at initial pH of 5. Generally, Pb was sorbed more strongly with increasing pH from 3 to 5 than Cd and thus poses less environmental threat. Efficient removal of Pb was achieved at lower dose of goethite, as there was no appreciable increase in the amount of Pb adsorbed when the adsorbent dose was increased.

Removal of Pb(II) from aqueous solution by oxidized multiwalled carbon nanotubes

Oxidized multiwalled carbon nanotubes (MWCNTs) were employed as sorbent to study the sorption characteristic of Pb(II) from aqueous solution as a function of contact time, pH, ionic strength, foreign ions, and oxidized MWCNTs’ contents under ambient conditions using batch technique. The results indicate that sorption of Pb(II) on oxidized MWCNTs is strongly dependent on pH values, and independent of ionic strength and the type of foreign ions. The removal of Pb(II) to oxidized MWCNTs is rather quickly and the kinetic sorption can be described by a pseudo-second-order model very well. Sorption of Pb(II) is mainly dominated by surface complexation rather than ion exchange. The efficient removal of Pb(II) from aqueous solution is limited at pH 7–10. X-ray photoelectron spectroscopy (XPS) is performed to study the sorption mechanism at a molecular level and thereby to identify the species of the sorption processes. The 3-D relationship of pH, C eq and q indicates that all the data of C eq − q lie in a straight line with slope − V/ m and intercept C 0 V/ m for the same initial concentration of Pb(II) and same content of oxidized MWCNTs of each experimental data.

Removal of heavy metals using waste eggshell

The removal capacity of toxic heavy metals by the reused eggshell was studied. As a pretreatment process for the preparation of reused material from waste eggshell, calcination was performed in the furnace at 800°C for 2 h after crushing the dried waste eggshell. Calcination behavior, qualitative and quantitative elemental information, mineral type and surface characteristics before and after calcination of eggshell were examined by thermal gravimetric analysis (TGA), X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. After calcination, the major inorganic composition was identified as Ca (lime, 99.63%) and K, P and Sr were identified as minor components. When calcined eggshell was applied in the treatment of synthetic wastewater containing heavy metals, a complete removal of Cd as well as above 99% removal of Cr was observed after 10 min. Although the natural eggshell had some removal capacity of Cd and Cr, a complete removal was not accomplished even after 60 min due to quite slower removal rate. However, in contrast to Cd and Cr, an efficient removal of Pb was observed with the natural eggshell rather than the calcined eggshell. From the application of the calcined eggshell in the treatment of real electroplating wastewater, the calcined eggshell showed a promising removal capacity of heavy metal ions as well as had a good neutralization capacity in the treatment of strong acidic wastewater.

More efficient removal of Pb(II) from Ag(I) and Hg(I) in group I

More efficient removal of Pb(II) from Ag(I) and Hg(I) in group I