Search

The hydrogels-metal organic frameworks hybrid materials have received increasing attentions in recent years. The pectin hydrogel (PH) was derived from mandarin orange peels by-products and calcium chloride was applied as a cross-linker for incorporation with Fe-TAC metal organic frameworks (MOFs) for the formation of PHM composite on in situ synthesis method. The synthesized PHM composite was characterized by SEM, FT-IR, XRD and N 2 adsorption-desorption and investigated for the adsorption of anionic species, Cr(VI) as well as cationic species, Pb(II) ions from aqueous solution. The adsorption kinetics for Cr(VI)/Pb(II) ions removal followed the pseudo-second order kinetic model and the equilibrium adsorption data were well fitted by Langmuir model. The maximum adsorption capacities of Cr(VI)/Pb(II) ions were 825.97 and 913.88 mg g -1 , respectively. High swelling capacity (1500.0%) was also characterized for PHM composite after only 400 min and excellent stability for eight cycles with respect to regeneration with 0.1 mol L -1 HCl. The validity of PHM composite for simultaneous removal from real water matrices were confirmed as Cr(VI) (99.73, 99.87 and 99.87%) and Pb(II) (99.02, 98.55 and 98.55%) from tap water, sea water and industrial wastewater samples, respectively., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A novel marine fungus was isolated and classified as Aspergillus flavus strain EGY11. The heat-inactivated form of isolated Aspergillus flavus was investigated and evaluated as a new eco-friendly and highly efficient biosorbent for removal of toxic heavy metals such as Cd(II), Hg(II), and Pb(II) from aqueous solutions. The SEM morphological studies of biosorbent-loaded metal ions confirmed their direct binding on the surface of heat-inactivated Aspergillus flavus. The metal biosorption capacity values were determined and optimized by the batch technique in the presence of various experimental controlling factors such as pH, contact time, biosorbent dosage, initial metal ion concentration, and coexisting species. The maximum metal capacity values of Cd(II), Hg(II), and Pb(II) were cauterized as 1550 (pH 7.0), 950 (pH 7.0), and 1000 μmol g -1 (pH 6.0), respectively. The equilibrium time for removal of metal ions was identified as 40 min. The maximum sorption capacity values (1200.0-4000.0 μmol g -1 ) were established by 5.0 mg as the optimum mass of biosorbent. The collected biosorption data obtained from the equilibrium studies using the initial metal ion concentration were described by the Langmuir, Freundlich, Brunauer-Emmett-Teller (BET), and Dubinin-Radushkevich isotherm (D-R) isotherm models. The potential implementation of heat-inactivated Aspergillus flavus biosorbent for heavy metal removal from different water samples was successfully accomplished using multistage microcolumn technique. The results refer to excellent percentage recovery values in the ranges 92.7-99.0, 91.3-95.6, and 95.3-98.2% for the biosorptive removal of Cd(II), Hg(II), and Pb(II), respectively, from the examined environmental samples.

Novel biosorbent systems were designed, investigated and implemented for bioaccumulation of Pb(II) from aqueous solutions. These are based on the combination of SiO(2)-nanoparticles (N-Si) with Penicillium funiculosum fungus (Pen) for the formation of (N-Si-Pen) as well as heat inactivated Penicillium funiculosum (Pen). The SiO(2)-nanoparticles were also investigated as a solid sorbent phase. Surface characterization and immobilization were examined and confirmed by using FT-IR and SEM analysis. A batch equilibrium technique was used to follow-up the adsorption processes of lead under the effect of pH, contact time, sorbent dosage and initial metal concentration. The maximum capacity values were 1200.0 and 1266.7μmolg(-1) for (Pen) and (N-Si-Pen), respectively at pH 5. Sorption equilibria were established in ∼20min and their data were well described by Langmuir, Freundlich and Dubinin-Radushkevich models. The potential applications of these biosorbents for extraction of Pb(II) from real samples contaminated with lead, were successfully accomplished., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

A method is described for hybridization of the adsorption and biosorption characteristics of chemically treated commercial activated carbon and baker's yeast, respectively, for the formation of environmental friendly multifunctional sorbents. Activated carbon was loaded with baker's yeast after acid-base treatment. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) Spectroscopy were used to characterize these sorbents. Moreover, the sorption capabilities for lead (II) ions were evaluated. A value of 90 μmol g(-1) was identified as the maximum sorption capacity of activated carbon. Acid-base treatment of activated carbon was found to double the sorption capacity (140-180 μmol g(-1)). Immobilization of baker's yeast on the surface of activated carbon sorbents was found to further improve the sorption capacity efficiency of lead to 360, 510 and 560 μmol g(-1), respectively. Several important factors such as pH, contact time, sorbent dose, lead concentration and interfering ions were examined. Lead sorption process was studied and evaluated by several adsorption isotherms and found to follow the Langmuir and BET models. The potential applications of various chemically and biologically modified sorbents and biosorbents for removal of lead from real water matrices were also investigated via multistage micro-column technique and the results referred to excellent recovery values of lead (95.0-99.0 ± 3.0-5.0 %).

Hybrid sorbents and biosorbents were synthesized via chemical and biological treatment of active carbon by simple and direct redox reaction followed by surface loading of baker's yeast. Surface functionality and morphology of chemically and biologically modified sorbents and biosorbents were studied by Fourier Transform Infrared analysis and scanning electron microscope imaging. Hybrid carbonaceous sorbents and biosorbents were characterized by excellent efficiency and superiority toward lead(II) sorption compared to blank active carbon providing a maximum sorption capacity of lead(II) ion as 500 μmol g(-1). Sorption processes of lead(II) by these hybrid materials were investigated under the influence of several controlling parameters such as pH, contact time, mass of sorbent and biosorbent, lead(II) concentration, and foreign ions. Lead(II) sorption mechanisms were found to obey the Langmuir and BET isotherm models. The potential applications of chemically and biologically modified-active carbonaceous materials for removal and extraction of lead from real water matrices were also studied via a double-stage microcolumn technique. The results of this study were found to denote to superior recovery values of lead (95.0-99.0 ± 3.0-5.0%) by various carbonaceous-modified-bakers yeast biosorbents.

In this work, the effect of adding Pb nano/microparticles in polyurethane foams to improve thermo-physical and mechanical properties were investigated. Moreover, an attempt has been made to modify the micron-sized lead metal powder into nanostructured Pb powder using a high-energy ball mill. Two types of fillers were used, the first is Pb in micro scale and the second is Pb in nano scale. A lead/polyurethane nanocomposite is made using the in-situ polymerization process. The different characterization techniques describe the state of the dispersion of fillers in foam. The effects of these additions in the foam were evaluated, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) have all been used to analyze the morphology and dispersion of lead in polyurethane. The findings demonstrate that lead is uniformly distributed throughout the polyurethane matrix. The compression test demonstrates that the inclusion of lead weakens the compression strength of the nanocomposites in comparison to that of pure polyurethane. The TGA study shows that the enhanced thermal stability is a result of the inclusion of fillers, especially nanofillers. The shielding efficiency has been studied, MAC, LAC, HVL, MFP and Zeff were determined either experimentally or by Monte Carlo calculations. The nuclear radiation shielding properties were simulated by the FLUKA code for the photon energy range of 0.0001–100 MeV. [ABSTRACT FROM AUTHOR]

A chemical modification method is presented to establish a surface functionalization procedure of amino modified nanosilica (NS-amine) with 1-(3-cyanopropyl)-3-methylimidazolium-bis(trifluoromethylsulfonyl) type of ionic liquid, [CN-C 3 -MIm] + [NTf 2 ] − for the formation of a novel NS-amine-IL nanocomposite. Based on the TEM analysis and DLS technique, the diameter of the proposed nanocomposite was found 25.4 ± 0.8 nm. The designed NS-amine-IL nanocomposite was additionally characterized using FT-IR, XRD, EDX, TGA, SEM and zeta potential. The sequestration performance of NS-amine-IL was investigated for remediation of bivalent lead and cadmium ions from aqueous solutions. The effects of medium acidity, contact time, NS-amine-IL dosage, interfering ions, temperature and initial adsorbates concentrations on the removal processes of investigated cations were excessively studied. The maximum extraction values of Pb(II) and Cd(II) were recorded at pH 4–5 and pH 7, respectively. The thermodynamic profiles of the adsorption process were searched at optimal conditions. The adsorption processes were feasibly endothermic and fitted well with the Langmuir isotherm and pseud o-second-order kinetics equation. The experimental data indicated that the novel nanocomposite was a promising material for the extraction of both metal ions from wastewater and soil samples with determined recoveries 98.0–99.0% ± 4.9. [ABSTRACT FROM AUTHOR]

A method is described for the selective separation and extraction of cadmium-lead from aqueous solutions by tuning the pH value between 1.0 and 7.0. A modified nano-active silica sorbent was loaded with 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide hydrophobic ionic liquid, [Bmim+Tf2N−] and used in this work. The pH value was found to play a significant role in the sorption capacity of Cd(II) and Pb(II). In pH 1.0, the metal capacity values were characterized as 1.40 and 0.30 mmol g−1for Cd(II) and Pb(II), respectively. In pH 7.0, Cd(II) and Pb(II) switched their capacity values to 0.65 and 1.00 mmol g−1, respectively. An anion exchange mechanism was proposed in solution with pH 1.0 for exchange of chloroanionic cadmium species by [Tf2N−]. The sorptive separation processes of Cd(II) and Pb(II) were studied and evaluated under the influence of various controlling factors. The potential applications of modified nano-silica sorbent for selective sorptive removal and separation of Cd(II) from Pb(II) in water samples was successfully accomplished by adjusting the pH value of the contact solution between 1.0 and 7.0. The results of this study indicated an efficient extraction behavior of the two examined metal ions. [ABSTRACT FROM AUTHOR]

Abstract: Novel biosorbent systems were designed, investigated and implemented for bioaccumulation of Pb(II) from aqueous solutions. These are based on the combination of SiO2-nanoparticles (N-Si) with Penicillium funiculosum fungus (Pen) for the formation of (N-Si-Pen) as well as heat inactivated Penicillium funiculosum (Pen). The SiO2-nanoparticles were also investigated as a solid sorbent phase. Surface characterization and immobilization were examined and confirmed by using FT-IR and SEM analysis. A batch equilibrium technique was used to follow-up the adsorption processes of lead under the effect of pH, contact time, sorbent dosage and initial metal concentration. The maximum capacity values were 1200.0 and 1266.7μmolg−1 for (Pen) and (N-Si-Pen), respectively at pH 5. Sorption equilibria were established in ∼20min and their data were well described by Langmuir, Freundlich and Dubinin–Radushkevich models. The potential applications of these biosorbents for extraction of Pb(II) from real samples contaminated with lead, were successfully accomplished. [Copyright &y& Elsevier]

Abstract: This paper demonstrates, for the first time, that 1-methyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM + Tf 2 N − ] hydrophobic ionic liquid can be potentially used as an excellent medium for solid phase extraction of Pb(II) from water matrices. In this work, [EMIM + Tf 2 N − ] was directed to synthesize two newly modified nano-silica sorbents. The first modified sorbent was based on surface derivatization via physical adsorption of [EMIM + Tf 2 N − ] onto active nano-silica particles (10–20nm) for the formation of [NSi-OH-EMIM + Tf 2 N − ]. The second sorbent was prepared by the direct reaction of [EMIM + Tf 2 N − ] with amino modified nano-silica particles for the preparation of [NSi-NH 2 -EMIM + Tf 2 N − ]. Surface modification of nano-silica particles was characterized and confirmed by surface coverage determination as well as instrumental analysis by using a scanning electron microscope (SEM), FT-IR and thermal analysis. The capability of newly modified nano silica sorbents for extraction of lead (II) without the need for a partition chelating intermediate was studied and optimized under different controlling variables including the effect of Pb(II) concentration, sorbent dose, pH of contact medium, shaking time, interfering anions and cations. The potential applications of [NSi-OH-EMIM + Tf2N−] and [NSi-NH 2 -EMIM + Tf 2 N − ] for solid phase extraction of Pb(II) from real water matrices via multi-stage micro-column separation were also studied and evaluated. [ABSTRACT FROM AUTHOR]

Abstract: The hydrophobic character incorporated into 1-methyl-3-octylimidazolium bis(trifluoromethyl-sulfonyl)imide [OMIM+Tf2N−] based on both the anion and cation natures was employed to develop a novel solid phase extraction medium based on physical adsorption approach. Two modified nano-silica sorbents were synthesized via direct immobilization of [OMIM+Tf2N−] on the surface of active nano-silica [NSi-OH] and amino nano-silica [NSi-NH2] for the formation of [NSi-OH-OMIM+Tf2N−] and [NSi-NH2-OMIM+Tf2N−], respectively. Surface characterization was confirmed by TGA, FT-IR and SEM. The surface coverage values were identified in the range of 1.223–1.272mmolg−1. Modified sorbents were extensively studied and characterized by their high similarity and affinity for lead extraction without the need for chelating intermediate. Excellent sorption capacity values (0.5–0.9 and 0.8–1.3mmolg−1) of lead were determined in pH 1–7. Other factors such as reaction contact time, sorbent dose, initial metal ion concentration and interfering ions were studied to spot more light on the sorption capability of loaded hydrophobic ionic liquid for application in the solid phase extraction mode. These sorbents were successfully implemented for removal and preconcentration of lead from various water samples via application of a multi-stage micro-column giving rise to percentage recovery values of lead in the range of 98.0–100.0±3.0–4%. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the removal and preconcentration of Pb(II) from drinking tap water and wastewater samples via applications of newly modified three alumina–physically loaded-dithizone adsorbents. The synthesized acidic, neutral and basic alumina adsorbents (I), (II) and (III), respectively are characterized by a strong stability toward acid leaching and thermal decomposition. Sorption of Pb(II) was investigated as a function of the solution pH and contact time. The incorporated selectivity characteristics into alumina adsorbents were studied and the results of metal sorption capacity showed the strong affinity toward Pb(II), Cr(III) and Cu(II). Determination of the distribution coefficient and separation factors indicated that these alumina adsorbents are highly selective for Pb(II). Selective removal of Pb(II) from wastewater samples was accomplished with percentage recovery values of 94–99±1–2%, while the results collected from the selective preconcentration of Pb(II) from drinking tap water proved excellent percentage recovery values of 96–99±2–3% and 94–99±2–4% for the two studied concentration values 1.212ngml−1 and 4.800ngml−1, respectively. [Copyright &y& Elsevier]

Hydrogels and mixed hydrogels are 3D-hydrophilic polymeric structures with high porosity, soft consistency and excellent absorbing capability of large amounts of water and organic/inorganic pollutants. Therefore, the present work is aimed to graft starch-gelatin mixed hydrogels with magnetic spinel ferrite@biochar@molybdenum oxide to produce a novel nanocomposite (MoO 3 /MSB@CoFe 2 O 4 @Gel/Starch) with high Pb(II)uptake efficiency. The nanocomposite was assembled from MoO 3 , super magnetic CoFe 2 O 4 , waste mallow stems biochar (MSB) and gelatin-esterified starch mixed hydrogels (Gel/Starch) and characterized by FT-IR, EDX, XRD, SEM and XPS techniques. The EDX analysis of nanocomposite referred to existence of C, O, Na, N, Mo, Fe and Co with 26.68%, 29.44%, 4.55%, 3.48%, 19.72%, 10.39% and 5.74%, respectively. The swelling properties of MoO 3 /MSB@CoFe 2 O 4 @Gel/Starch produced 438% maximum swelling. The average size (27.66 nm) of nanocomposite was estimated from the XRD analysis. The maximum adsorption capacities of Pb(II) onto hydrogels were 2075, 4375 and 5000 μmol g−1 as optimized and established using 20 mg and 40 min reaction time by 0.05, 0.1 and 0.15 mol L−1 Pb(II) ions, respectively. The XPS analysis referred to a peak at BE 138.42 eV corresponding to Pb 4 f as the main product for adsorption of Pb(II). The kinetics and adsorption isotherm models referred to a combination of chemi-physi-sorption processes. The kinetic analysis and the mechanisms for removal of Pb(II) and conversion into Pb(0) were explored and characterized in this study based on the XPS analysis. The reusability test of MoO 3 /MSB@CoFe 2 O 4 @Gel/Starch mixed hydrogels-loaded-Pb(II)/Pb(0) was investigated and referred to a slight loss (~ 2%) after five continuous recycles. [Display omitted] • A novel nanocomposite of MoO 3 -biochar- CoFe 2 O 4 -gelatin/starch mixed hydrogel. • EDX-XRD-XPS-SEM-FTIR techniques were employed for characterization. • MoO 3 /MSB@CoFe 2 O 4 @Gel/Starch hydrogel confirmed a maximum swelling (438%). • Removal optimization of Pb(II) ions via successive adsorption and reduction. • 20 mg hydrogel and 40 min produced 5000 μmol g−1 capacity for 0.15 mol L−1 of Pb(II). [ABSTRACT FROM AUTHOR]

• Preparation of α-FeOOH and then FeOOH-Cellulose-TiO 2 hybrid nanocomposite was designed by a simple and eco-friendly method. Full Characterization of FeOOH-Cellulose-TiO 2 hybrid nanocomposite using FT-IR, SEM, TGA and XRD. • FeOOH-Cellulose-TiO 2 hybrid nanocomposite was used as adsorbent for Pb(II) from water. A comparative study between batch equilibrium method and microwave sorption technique was established under the influence of various conditional factors like pH, contact time, sorbent dose, metal ion concentration and interfering ions. • Kinetics study like pseudo -first-order, pseudo -second-order, Elovich and Intraparticle diffusion models were applied in this work. Adsorption isotherm models like Langmuir Freundlich, Temkin and D-R isotherm were applied in this work. • The maximum metal capacity values using 5 mg of FeOOH-Cellulose-TiO 2 nanocomposite was 9600 µmol.g−1 in 20 seconds by the microwave sorption technique, while that by batch equilibrium technique was characterized as 8800 µmol.g−1 at 30 min. Application on removal of Pb(II) from real water/ wastewater samples In this work, FeOOH-Cellulose-TiO 2 hybrid nanocomposite was prepared via formaldehyde crosslinker and used for lead ions, Pb(II), remediation from water. Adsorption of Pb(II) from the water done by using batch and microwave adsorption approaches. According to this work, the microwave adsorption technique showed the best adsorption efficiency. The extraction of lead (II) under microwave irradiation was accomplished via controlled parameters (pH 7 with short contact time 20 sec) and the maximum metal capacity value (9600 µmol.g−1) obtained by using 5 mg of FeOOH-Cellulose-TiO 2 nanocomposite. Kinetic model and adsorption isotherm study revealed the best fitting with Lagergren-second-order and D-R model, respectively. The efficiency of FeOOH-Cellulose-TiO 2 nanocomposite for removal of Pb(II) from tap water and wastewater was configured by using column technique and microwave technique. The highest percent removal values of Pb(II) from tap and wastewater samples were 98% and 99%, respectively. [ABSTRACT FROM AUTHOR]

• Graphene Quantum Dots-Barium hydroxide has been synthesized. • Ultrafast removal of Pb(II) and la(III) by microwave irradiation technique. • Maximum removal of Pb(II) and La(III) at 15 s. • Adsorption isotherms, kinetics and thermodynamic parameters were investigated. • Excellent removal of Pb(II) and La(III) ions from wastewater and tap water. In this study, rice husk was used as a sustainable source to synthesize graphene quantum dots (GQDOs) with 2D morphology. Chemical modification of GQDOs with Ba(OH) 2 was followed to form a novel GQDOs-Ba nanobiosorbent with an increased number of surface hydroxyl groups. The physicochemical properties of GQDOs and GQDOs-Ba were investigated by FT-IR, SEM, TEM, TGA, and XRD. The adsorption parameters of Pb(II) and La(III) onto GQDOs-Ba were optimized using microwave sorption approach. The maximum capacity reached 3400 µmol g−1 (pH 7), and 1500 µmol g−1 (pH 5) at 15 s for Pb(II) and La(III), respectively. The adsorption isotherm models by GQDOs-Ba fitted well with Langmuir. The pseudo -second order was agreed by Pb(II) and La(III) ions. The thermodynamic studies elucidated that Pb(II) and La(III) adsorption onto GQDOs-Ba followed a spontaneous model. The GQDOs-Ba nanobiosorbent accomplished excellent removal percentages from different water samples containing lead (98.5%–99.8%) and lanthanum (94.6%–96.2%). [ABSTRACT FROM AUTHOR]