Single, binary and multi-component adsorption of copper and cadmium from aqueous solutions on Kraft lignin--a biosorbent

A new biosorbent for removing toxic metal ions from water/industrial wastewater has been investigated using by-product lignin from paper production. Lignin was extracted from black liquor waste, characterized and utilized for the removal of copper and cadmium from aqueous solutions in single, binary and multi-component systems. Adsorption studies were conducted at different temperatures, lignin particle sizes, pHs and solid to liquid ratios. All the studies were conducted by a batch method to determine equilibrium and kinetic parameters. The Langmuir and Freundlich isotherm models were applied. The Langmuir model fits best the equilibrium isotherm data. The maximum lignin adsorption capacities at 25 degrees C were 87.05 mg/g (1.37 mmol/g) and 137.14 mg/g (1.22 mmol/g) for Cu(II) and Cd(II), respectively. Adsorption of Cu2+ (68.63 mg/g at 10 degrees C and 94.68 mg/g at 40 degrees C) and Cd2+ (59.58 mg/g at 10 degrees C and 175.36 mg/g at 40 degrees C) increased with an increase in temperature. Copper and cadmium adsorption followed pseudo-second order rate kinetics. From kinetic studies, various rate and thermodynamic parameters such as effective diffusion coefficients, activation energy, and activation entropy were evaluated. Adsorption occurs through a particle diffusion mechanism at temperatures 10 and 25 degrees C while at 40 degrees C it occurs through a film diffusion mechanism. The sorption capacity of black liquor lignin is higher than many other adsorbents/carbons/biosorbents utilized for the removal of Cu(II) and Cd(II) from water/wastewater in single and multi-component systems.     

Adsorptive Removal of Cd,Cu, Ni and Mn from Environmental Samples Using Fe3O4-Zro2@APS Nanocomposite: Kinetic and Equilibrium Isotherm Studies

In this study, Fe₃O₄-ZrO₂ functionalized with 3-aminopropyltriethoxysilane (Fe₃O₄-ZrO₂@APS) nanocomposite was investigated as a nanoadsorbent for the removal of Cd(II), Cu(II), Mn (II) and Ni(II) ions from aqueous solution and real samples in batch mode systems. The prepared magnetic nanomaterials were characterized using X-ray powder diffraction (XRD), scanning electron microscopy/energy dispersion x-ray (SEM/EDX) Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Factors (such as adsorbent dose and sample pH) affecting the adsorption behavior of the removal process were studied using the response surface methodology. Under optimized condition, equilibrium data obtained were fitted into the Langmuir and Freundlich isotherms and the data fitted well with Langmuir isotherms. Langmuir adsorption capacities (mg/g) were found to be 113, 111, 128, and 123 mg/g for Cd, Cu, Ni and Mn, respectively. In addition, the adsorption kinetics was analyzed using five kinetic models, pseudo-first order, pseudo-second order, intraparticle diffusion and Boyd models. The adsorbent was successfully applied for removal of Cd(II), Cu(II), Mn (II) and Ni(II) ions in wastewater samples.     

Adsorptive accumulation of Cd(II), Co(II), Cu(II), Pb(II), and Ni(II) from water on montmorillonite: influence of acid activation

The present work investigates the influence of acid activation of montmorillonite on adsorption of Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) from aqueous medium and comparison of the adsorption capacities with those on parent montmorillonite. The clay-metal interactions were studied under different conditions of pH, concentration of metal ions, amount of clay, interaction time, and temperature. The interactions were dependent on pH and the uptake was controlled by the amount of clay and the initial concentration of the metal ions. The adsorption capacity of acid-activated montmorillonite increases for all the metal ions. The interactions were adsorptive in nature and relatively fast and the rate processes more akin to the second-order kinetics. The adsorption data fitted both Langmuir and Freundlich isotherms, indicating that strong forces were responsible for the interactions at energetically nonuniform sites. The Langmuir monolayer capacity of the acid-activated montmorillonite is more than that of the parent montmorillonite (Cd(II): 32.7 and 33.2 mg/g; Co(II): 28.6 and 29.7 mg/g; Cu(II): 31.8 and 32.3 mg/g; Pb(II): 33.0 and 34.0 mg/g; and Ni(II): 28.4 and 29.5 mg/g for montmorillonite and acid-activated montmorillonite, respectively). The thermodynamics of the rate processes showed the adsorption of Co(II), Pb(II), and Ni(II) to be exothermic, accompanied by decreases in entropy and Gibbs free energy, while the adsorption of Cd(II) and Cu(II) was endothermic, with an increase in entropy and an appreciable decrease in Gibbs free energy. The results have established the potential use for montmorillonite and its acid-activated form as adsorbents for Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) ions from aqueous media.     

Biosorption of nickel(II) and copper(II) ions from aqueous solution by Streptomyces coelicolor A3(2)

The biosorption of nickel(II) and copper(II) ions from aqueous solution by dried Streptomyces coelicolor A3(2) was studied as a function of concentration, pH and temperature. The optimum pH range for nickel and copper uptake was 8.0 and 5.0, respectively. At the optimal conditions, metal ion uptake was increased as the initial metal ion concentration increased up to 250 mg l(-1). At 250 mg l(-1) copper(II) ion uptake was 21.8% whereas nickel(II) ion uptake was found to be as high as 7.3% compared to those reported earlier in the literature. Metal ion uptake experiments were carried out at different temperatures where the best ion uptake was found to be at 25 degrees C. The characteristics of the adsorption process were investigated using Scatchard analysis at 25 degrees C. Scatchard analysis of the equilibrium binding data for metal ions on S. coelicolor A3(2) gave rise to a linear plot, indicating that the Langmuir model could be applied. However, for nickel(II) ion, divergence from the Scatchard plot was evident, consistent with the participation of secondary equilibrium effects in the adsorption process. Adsorption behaviour of nickel(II) and copper(II) ions on the S. coelicolor A3(2) can be expressed by both the Langmuir and Freundlich isotherms. The adsorption data with respect to both metals provide an excellent fit to the Freundlich isotherm. However, when the Langmuir isotherm model was applied to these data, a good fit was obtained for the copper adsorption only and not for nickel(II) ion.     

Fabrication of SiO2/CuFe2O4/polyaniline composite: A highly efficient adsorbent for heavy metals removal from aquatic environment

A novel multifunctional of SiO₂/CuFe₂O₄/polyaniline composite was synthesized through the interaction between silica (SiO₂), copper iron oxide (CuFe₂O₄), and polyaniline (PANI) as starting materials. SiO₂/CuFe₂O₄/polyaniline composite was characterized for morphology, crystallinity, textural properties, and utilised for the removal of Fe(II), Mn(II), and Cu(II) from synthetic wastewater solutions. The roles of solution pH (2.0–6.0), interaction time (15–420 min), initial ion concentration (50–700 mg/L), and solution temperature (30–50 °C) in the adsorption process were investigated. The adsorption capacities of SiO₂/CuFe₂O₄/PANI for the tested metal ions were high compared to SiO₂, CuFe₂O_4, and polyaniline. Equilibrium studies indicated that Fe(II) and Mn(II) adsorption were compliant with the Langmuir model, while the Freundlich equation described the removal of Cu(II) ions. The maximum Langmuir capacities were up to 285.71, 416.67, and 454.55 mg/g for Cu(II), Fe(II), and Mn(II), respectively. The pseudo-first-order kinetic model fitted well the metal ions removal data. The rate-controlling step reflected the involvement of surface and inner pore diffusion (intraparticle) processes. Electrostatic attractions and chelation were mainly responsible for the binding of metals ions onto SiO₂/CuFe₂O₄/PANI. The selectivity of the studied ions was governed mainly by the hydrated ionic radii and the composite adsorption active sites. SiO₂/CuFe₂O₄/PANI can be easily reused with a slight decrease (around 2–3%) in metal removal efficiency after four successive regeneration cycles.     

Investigations into the kinetics and thermodynamics of Sb(III) adsorption on goethite (alpha-FeOOH)

This study reports thermodynamic and kinetic data of Sb(III) adsorption from single metal solutions onto synthetic aqueous goethite (alpha-FeOOH). Batch equilibrium sorption experiments were carried out at 25 degrees C over a Sb:Fe molar range of 0.005-0.05 and using a goethite concentration of 0.44 g Fe/L. Experimental data were successfully modelled using Langmuir (R2 > or = 0.891) and Freundlich (R2 > or = 0.990) isotherms and the following parameters were derived from triplicate experiments: Kf = 1.903 +/- 0.030 mg/g and 1/n = 0.728 +/- 0.019 for the Freundlich model and b = 0.021 +/- 0.003 L/mg and Qmax = 61 +/- 8 mg/g for the Langmuir model. The thermodynamic parameters determined were the equilibrium constant, Keq =1.323 +/- 0.045, and the Gibb's free energy, DeltaG0 = -0.692 +/- 0.083 kJ/mol. The sorption process is very fast. At a Sb:Fe molar ratio of 0.05, 40-50% of the added Sb is adsorbed within 15 min and a steady state is achieved. The experimental data also suggest that desorption can occur within 24 h of reaction due to the oxidation of Sb(III) on the goethite surface. Finally, calculated pH of the aqueous solution using MINTEQ2 agrees well with the measured pH (3.9 +/- 0.7; n = 30). At pH 4, the dominant Sb species in solution are Sb(OH)3 and HSbO2 which both likely adsorb as inner sphere complexes to the positively charged goethite surface.     

Carbon nanotubes modified with 5,7-dinitro-8-quinolinol as potentially applicable tool for efficient removal of industrial wastewater pollutants

The environmental pollution due to the industrial wastewater of four different areas in the Gulf of Suez, Red Sea, Egypt, was studied. Adsorption capacities toward the concerned heavy metal ions Cu(II), Zn(II), Fe(II), and Pb(II) by multiwalled carbon nanotubes (MWCNTs) and modified-MWCNTs with 5,7-dinitro-8-quinolinol were investigated. MWCNTs as well as the modified-MWCNTs were characterized using Fourier transform infrared (FTIR), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Adsorption of the studied divalent metal ions was measured by atomic absorption spectrometry (AAS). The effects of solution conditions such as pH, shaking time, metal ion concentration, ionic strength and adsorbent dosage on the adsorption process were also examined. The obtained results showed that removals of the heavy metal ions under consideration by MWCNTs are obviously dependent on the experimental conditions. The maximum adsorption capacities as calculated applying Langmuir equation to single ion adsorption isotherms were found to be 142.8 mg/g for Cu(II), 250 mg/g for Zn(II), 111.1 mg/g for Fe(II), and 200 mg/g for Pb(II) using MWCNTs; meanwhile, the modified-MWCNTs exhibited higher values of the respective maximum adsorption capacities as 333.3 mg/g for Cu(II), 500 mg/g for Zn(II), 200 mg/g for Fe(II), and 333.3 mg/g for Pb(II). Kinetic studies were also performed and the experimental data followed a pseudo-second order model of the adsorption process. The obtained results suggest that the tested adsorption systems of MWCNTs and modified-MWCNTs have suitable affinity toward the metal ion under consideration. Both systems could act as potentially applicable tool in environmental protection.     

New anion-exchange solid-phase extraction support used for preconcentration and determination of lead in water samples by flame atomic absorption spectrometry

A new chelating resin was prepared by coupling Amberlite XAD-2 with Brilliant Green through an azo spacer. The resulting resin has been characterized by FTIR spectrometry, elemental analysis, and thermogravimetric analysis and studied for the preconcentration and determination of trace Pb(II) ions from solution samples. The anionic complex of Pb(II) and iodide was retained on the resin by the formation of an ion associate with Brilliant Green on Amberlite XAD-2 in weak acidic medium. The optimum pH value for sorption of the metal ion was 5.5. The sorption capacity of the functionalized resin is 53.8 mg/g. The chelating resin can be reused for 20 cycles of sorption-desorption without any significant change in sorption capacity. A recovery of 103% was obtained for the metal ion with 0.1 M EDTA as the eluting agent. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The resin was subjected to evaluation through batch binding and column chromatography of Pb(II). The equilibrium adsorption data of Pb(II) on modified resin were analyzed by Langmuir, Freundlich, and Temkin models. Based on equilibrium adsorption data, the Langmuir, Freundlich, and Temkin constants were determined to be 0.192, 13.189, and 3.418 at pH 5.5 and 25 degrees C. The method was applied for lead ion determination in tap water samples.     

巯基树脂对金属离子的吸附性能(Ⅱ)

研究了自合成的巯基树脂对重金属离子Ag 、Hg2 、Cr3 的吸附容量、吸附动力学、等温吸附过程等静态吸附性能,影响吸附的因素和吸附机理.结果表明,该树脂对上述3种离子吸附能力强,吸附量分别达6.56mmol/g、3.25mmol/g、2.10mmol/g.树脂对各重金属离子等温吸附在实验浓度范围内符合Langmuir或Freundlich方程.吸附机理研究表明,巯基与金属离子发生了离子交换和配位反应,化学吸附起支配作用;另外树脂对Ag 、Hg2 吸附过程中存在一定的氧化还原现象.     

Removal of Cd(II), Cu(II), and Pb(II) by adsorption onto natural clay: a kinetic and thermodynamic study

In this work, we study the elimination of three bivalent metal ions (Cd²⁺, Cu²⁺, and Pb²⁺) by adsorption onto natural illitic clay (AM) collected from Marrakech region in Morocco. The characterization of the adsorbent was carried out by X-ray fluorescence, Fourier transform infrared spectroscopy and X-ray diffraction. The influence of physicochemical parameters on the clay adsorption capacity for ions Cd²⁺, Cu²⁺, and Pb²⁺, namely the adsorbent dose, the contact time, the initial pH imposed on the aqueous solution, the initial concentration of the metal solution and the temperature, was studied. The adsorption process is evaluated by different kinetic models such as the pseudo-first-order, pseudo-second-order, and Elovich. The adsorption mechanism was determined by the use of adsorption isotherms such as Langmuir, Freundlich, and Temkin models. Experiments have shown that heavy metals adsorption kinetics onto clay follows the same order, the pseudo-second order. The isotherms of adsorption of metal cations by AM clay are satisfactorily described by the Langmuir model and the maximum adsorption capacities obtained from the natural clay, using the Langmuir isotherm model equation, are 5.25, 13.41, and 15.90 mg/g, respectively for Cd(II), Cu(II), and Pb(II) ions. Adsorption of heavy metals on clay is a spontaneous and endothermic process characterized by a disorder of the medium. The values of ΔH are greater than 40 kJ/mol, which means that the interactions between clay and heavy metals are chemical in nature.     

Single, binary and multi-component adsorption of some anions and heavy metals on environmentally friendly Carpobrotus edulis plant

A low-cost adsorbent and environmentally friendly adsorbent from Carpobrotus edulis plant was used for the removal of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions from single, binary and multi-component systems. The efficiency of the adsorbent was studied using batch adsorption technique under different experimental conditions by varying parameters such as pH, initial concentration and contact time. In single component systems, the dried C. edulis has the highest affinity for Pb(2+), followed by NO(3)(-), Cd(2+) and H(2)PO(4)(-), with adsorption capacities of 175mg/g, 125mg/g, 28mg/g and 26mg/g, respectively. These results showed that the adsorption of NO(3)(-) and H(2)PO(4)(-) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. Freundlich adsorption model, showed the best fit to the single and binary experimental adsorption data. These results also indicated that the adsorption yield of Pb(2+) ion was reduced by the presence of Cd(2+) ion in binary metal mixture. The competitive adsorption of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions on dried C. edulis plant shows that NO(3)(-) and H(2)PO(4)(-) anions are able to adsorb on different free binding sites and Pb(2+) and Cd(2+) cations are able to adsorb on the same active sites of C. edulis particles. The dried C. edulis was found to be efficient in removing nitrate, phosphate, cadmium and lead from aqueous solution as compared to other adsorbents already used for the removal of these ions.     

Cellulose/poly(ethylene imine) composites as efficient and reusable adsorbents for heavy metal ions

A series of Cellulose/poly-ethylene imine (PEI) composites were prepared by grafting hyperbranched PEI onto cellulose chains in alkali/urea aqueous solvent system through “one step” method. The SEM results showed that the Cellulose/PEI composite maintained porous structure. The Cellulose/PEI composites were tested as Cu(II) adsorbents through thermodynamics and kinetics study. The adsorption process followed pseudo-second-order kinetics equation. The adsorption isotherms could be described by both Langmuir and Freundlich isotherm models. The maximum adsorption amount was calculated to be 285.7 mg/g. The composites showed good stability so that they could be used in a wide range of pH and temperature. Besides, the Cu(II) loaded Cellulose/PEI composite could also be easily regenerated by dilute sulfuric acid and still keep a major adsorption capacity. Finally, the adsorption capacities of Celluloes/PEI composite towards other metal ions, such as Zn(II), Ni(II), Cr(III) and Pb(II), were also demonstrated. It will be a new high-performance and environmental friendly material for sewage disposal and metal pollution treatment with promising developmental potential.     

Heavy metal removal from aqueous solution by Pseudevernia furfuracea (L.) Zopf

The present study was carried out in a batch system using a lichen (Pseudevernia furfuracea (L.) Zopf) for the sorption of nickel(II) and copper(II) ions from water. Particularly, the effect of pH, contact time and temperature were considered. Pseudevernia furfuracea exhibited nickel(II) and copper(II) uptake of 49.87 and 60.83 mg/g at an initial pH of 4 and 5-6 at 35 degrees C respectively. Both the Freundlich and Langmuir adsorption models were suitable for describing the biosorption of nickel(II) and copper(II) by the biosorbent. Biosorption showed pseudo first order rate kinetics for nickel and copper ions. Using the equilibrium constant values obtained at 25 and 35 degrees C, the thermodynamics properties of the biosorption (deltaG degrees, deltaH degrees and deltaS degrees) were determined. The biosorption of nickel(II) and copper(II) onto Pseudevernia furfuracea was found to be endothermic.     

Sorption of traces of silver ions onto polyurethane foam from acidic solution

The sorption of traces of silver ions onto polyurethane foam (PUF) has been investigated in detail. Maximum sorption of silver (K(d)=6109 cm(3) g(-1), %sorption>97.5%) has been achieved from 1 M nitric acid solution after equilibrating silver ions with approximately 29 mg PUF for 20 min. The kinetics and thermodynamics of the sorption of silver ions onto PUF have also been studied. The sorption of silver ions onto PUF follows a first-order rate equation, which results as 0.177 min(-1). The variation of sorption with temperature yields the values of DeltaH=-56.1+/-3.2 kJ mol(-1), DeltaS=-159.7+/-10.5 J mol(-1) K(-1) and DeltaG=-8.68+/-0.09 kJ mol(-1) at 298 K with a correlation factor gamma=0.9919. The sorption data were subjected to different sorption isotherms. The sorption follows Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. The values of Langmuir isotherms Q=65.4+/-1.5 mumol g(-1) and b=(4.79+/-1.16)x10(4) dm(3) mol(-1) have been evaluated for Langmuir sorption constants, whereas the Freundlich sorption isotherm gives the value 1/n=0.12+/-0.02 and A=0.15+/-0.03 mmol g(-1). The D-R parameters computed were beta=-0.000817+/-0.000206 mol(2) kJ(-2), X(m)=76.8+/-8.7 mumol g(-1) and E=24.7+/-3.2 kJ mol(-1). The influence of common ions on the sorption was also examined. It is observed that Hg(II), thiourea, Al(III), thiocyanate and thiosulphate reduce the sorption, whereas Cu(II), citrate and acetate ions enhance the sorption significantly. It can be concluded that PUF may be used to remove traces of silver ions from its very dilute solutions or for its preconcentration from aqueous acidic solutions.     

Potential application of termite mound for adsorption and removal of Pb(II) from aqueous solutions

The morphological and mineralogical composition of a termite mound from Ilorin, Nigeria was investigated with a view to understand its sorption properties. The termite hill soil was subjected to some spectroscopic analyses such as X-ray fluorescence (XRF) and Scanning Electron Microscopy. The XRF results revealed that the adsorbent contains a large fraction of Silicon, Iron and Aluminium minerals. The organic matter (OM) content expressed as percentage carbon was 3.45% while the high value of cation exchange capacity of 14.0?meq/100?g is in agreement with high percentage OM, which signifies high availability of exchangeable ions. The maximum Pb(II) adsorption capacity of the mound was found to be 15.5?mg/g. Batch adsorption experiments were carried out as a function of contact time, ionic strength and pH. Maximum and constant adsorption was observed in the pH range of 2?C5.5. The experimental results of Pb(II) adsorption were analyzed using Langmuir, Freundlich, and Temkin isotherms. The Langmuir and Temkin isotherms were found to fit the measured sorption data better than Freundlich. The constants obtained from the Langmuir model are maximum sorption value, Q _m?=?18.18 and Langmuir energy of adsorption constant, b?=?0.085, while the constants of the Freundlich model are the intensity of adsorption constant, n?=?0.134, and maximum diffusion constant, K _f?=?1.36. The adsorption data for Pb(II) was found to fit well into the pseudo-second order model. Desorption experiment was conducted using different concentrations of leachant and this was repeated three times to determine the life span of the adsorbent. It was observed that 0.2?M HCl had the highest desorption efficiency for reuse.     

Kinetics and equilibrium adsorption of Cu(II), Cd(II), and Ni(II) ions by chitosan functionalized with 2[-bis-(pyridylmethyl)aminomethyl]-4-methyl-6-formylphenol

Chitosan biopolymer chemically modified with the complexation agent 2[-bis-(pyridylmethyl)aminomethyl]-4-methyl-6-formylphenol (BPMAMF) was employed to study the kinetics and the equilibrium adsorption of Cu(II), Cd(II), and Ni(II) metal ions as functions of the pH solution. The maximum adsorption of Cu(II) was found at pH 6.0, while the Cd(II) and Ni(II) maximum adsorption occurred in acidic media, at pH 2.0 and 3.0, respectively. The kinetics was evaluated utilizing the pseudo-first-order and pseudo-second-order equation models and the equilibrium data were analyzed by Langmuir and Freundlich isotherms models. The adsorption kinetics follows the mechanism of the pseudo-second-order equation for all studied systems and this mechanism suggests that the adsorption rate of metal ions by CHS-BPMAMF depends on the number of ions on the adsorbent surface, as well as on their number at equilibrium. The best interpretation for the equilibrium data was given by the Langmuir isotherm and the maximum adsorption capacities were 109 mg g-1 for Cu(II), 38.5 mg g-1 for Cd(II), and 9.6 mg g-1 for Ni(II). The obtained results show that chitosan modified with BPMAMF ligand presented higher adsorption capacity for Cu(II) in all studied pH ranges.     

Adsorption of Cu(II), Zn(II), Ni(II), Pb(II), and Cd(II) from aqueous solution on Amberlite IR-120 synthetic resin

The adsorption of copper(II), zinc(II), nickel(II), lead(II), and cadmium(II) on Amberlite IR-120 synthetic sulfonated resin has been studied at different pH and temperatures by batch process. The effects of parameters such as amount of resin, resin contact time, pH, and temperature on the ion exchange separation have been investigated. For the determination of the adsorption behavior of the resin, the adsorption isotherms of metal ions have also been studied. The concentrations of metal ions have been measured by batch techniques and with AAS analysis. Adsorption analysis results obtained at various concentrations showed that the adsorption pattern on the resin followed Freundlich isotherms. Here we report the method that is applied for the sorption/separation of some toxic metals from their solutions.     

The adsorption of Cu(II) ions on bentonite--a kinetic study

The kinetics of sorption of Cu(2+) on a Saudi clay mineral (bentonite) was investigated at 20+/-0.5 degrees C using different weights of the clay (0.5, 1.0, 1.5, and 2 g). Each weight represents a certain sample size. The order of the process appeared to be 1 with respect to the Cu(2+), and 112 with respect to the clay surface area. The rate was found to depend on internal diffusion.,which produced a decrease in the specific rate of sorption as a function of time. Sorption characteristics were described using two site Langmuir isotherms. The desorption experiments proved that Cu(2+) ions are chemisorbed on the bentonite surface. The maximum adsorption obtained was 909 mg Cu(2+)/g clay. This value is of great significance, as it is much higher than any reported one.     

Synthesis and Application of Co‐Poly(2‐hydroxyethyl methacrylate‐ethylene dimethacrylate) Coupled with Alizarin Yellow for Preconcentration and Determination of Lead in Water Samples by Flame Atomic Absorption Spectrometry

Poly(2‐hydroxyethyl methacrylate‐ethylene dimethacrylate) (PHEMA‐EDMA) beads were produced by free radical co‐polymerization of 2‐hydroxyethyl methacrylate (HEMA) and ethylene dimethacrylate (EDMA). Then, metal complexing ligand alizarin yellow was covalently attached onto PHEMA‐EDMA beads. The resulting resin has been characterized by FT‐IR and studied for the preconcentration and determination of trace Pb(II) ion from solution samples. The optimum pH value for sorption of the metal ion was 5. The sorption capacity of functionalized resin is 100 mg.g^‐1. The chelating resin can be reused for 20 cycles of sorption‐desorption without any significant change in sorption capacity. A recovery of 96% was obtained for the metal ion with 0.1 M nitric acid as eluting agent. The equilibrium adsorption data of Pb(II) on modified resin were analyzed by Langmuir and Freundlich models. Based on equilibrium adsorption data the Langmuir and Freundlich constants were determined 2.571 and 418.7 at pH 5 and 25 °C. The method was applied for lead ions determination from well water sample.     

Development of Azo Dye Immobilized Sulfonated Poly (Glycidyl Methacrylate) Polymer Composite as Novel Adsorbents for Water Treatment Applications: Methylene Blue Immobilization Isotherm,Kinetic, Thermodynamic,and Simulations Studies

Methylene blue (MB) immobilized onto a sulfonated poly(glycidyl methacrylate) (SPGMA) polymer composite has been developed as a novel adsorbent for water treatment applications. The MB adsorptions onto sulfonated poly(glycidyl methacrylate) polymer characters have been studied. The adsorption isotherms, namely Langmuir and Freundlich, have been investigated. Other isotherm models. As a compromise between the Freundlich and Langmuir isotherm models, such as the D–R isotherm and the Temkin isotherm, have been compared. The results indicated that the adsorption process followed the Freundlich isotherm model, indicating heterogeneous surface site energies and multi-layer levels of sorption. This study selected three linear kinetic models, namely pseudo-first order, pseudo-second order, and Elovich, to describe the MB sorption process using SPGMA negatively charged nanoparticles (430 nm). The obtained data revealed that the adsorption process obeyed the pseudo-second-order kinetic model, suggesting that the rate-limiting step in these sorption processes may be chemisorption. Furthermore, the thermodynamic parameters have been evaluated. Moreover, the interaction of the MB molecules with SPGMA nanoparticles has been simulated using the governing equation that describes ion exchange resin derived from Nernst—Plank equations between two ion species. Finally, the developed MB-SPGMA composite adsorbent (27 mg/g) wastested for the first time for the removal of Cr⁶⁺ ions and Mn⁷⁺ metal ions from dichromate and permanganate-contaminated waters under mild adsorption conditions, opening a new field of multiuse of the same adsorbent in the removal of more than one contaminant.