Adsorption Kinetics Of Metal Ions Research Articles

Adsorption Potential, Speciation Transformation, and Risk Assessment of Hg-, Cd-, and Pb-Contaminated Soils Using Biochar in Combination with Potassium Dihydrogen Phosphate.

The objective of this study is to develop a remediation technology for composited heavy metal-contaminated soil. Biochars (BC300, BC400, and BC500) derived from corn were combined with potassium dihydrogen phosphate (KH2PO4) to immobilize and remove heavy metal ions, including mercury (Hg2+), cadmium (Cd2+), and lead (Pb2+). The adsorption kinetics of metal ions in aqueous solutions with different concentrations was tested, and the fitting effects of the two models were compared. The findings demonstrate that the joint application of biochar and KH2PO4 could markedly enhance the immobilization efficacy of Pb2+, whereas the utilization of KH2PO4 on its own exhibited a more pronounced immobilization impact on Cd2+. Furthermore, the present study underscores the shortcomings of various remediation techniques that must be taken into account when addressing heavy metal-contaminated soils. It also emphasizes the value of comprehensive remediation techniques that integrate multiple remediation agents. This study offers a novel approach and methodology for addressing the intricate and evolving challenges posed by heavy metal contamination in soil. Its practical value and potential for application are significant.

Metal tolerance and biosorption of Pb ions by Bacillus cereus RMN 1 (MK521259) isolated from metal contaminated sites

Recent years, metal pollution is an alarming factor to know about protects the environmental ecosystem due to the toxic, persistent and abundant in nature. Metals are present everywhere in the biotic and abiotic samples including soil, water, and microbes. The rate of bioaccumulation and biotransformation are very high. The excess concentration of the metals causes heavy metal pollution or contamination. Due to these defects, the removal of metals using biological sources is heightened in the current research. In this current investigation, the biosorption potential ability of the metal tolerable Bacillus cereus on Pb and Cu rich environment was chosen and thoroughly monitored. The 16s rRNA of the Bacillus cereus was sequenced, and named as Bacillus cereus RMN 1 (MK521259). The various test concentration (10–60 mg/mL) of Pb and Cu was exhibited the maximum removal percentages of 85.2% and 60.2%. The result of bisorption factors exhibited, 300 mg/mL of the biosorbent potency, 60 min contact time and pH 7, and they found to be optimal to remove the maximum of Pb ion from the solution. In the regression coefficients, the Freundlich and Langmuir isotherm models were used to study the adsorption kinetics of metal ions. In addition, the isotherm model confirmed that the of B. cereus biomass medicated metal adsorption was more favourable reaction for metal degradation. With the above evidences, the results of the present investigation proved that B. cereus derived biomass was actively adsorbing the metals ions. Thus we are recommending for the implementation of effective waste water treatment.

Adsorption of Pb(II) from water by treatment with an O-hydroxyphenyl thiourea-modified chitosan

An O-hydroxyphenyl thiourea-modified chitosan (OTCS) with excellent Pb(II) adsorption performance and selectivity was prepared as an adsorbent. The structure and morphology of the adsorbent were systematically investigated by SEM, BET, FTIR, EDX, zeta-potential measurements, XPS and XRD. The impacts of the initial Pb(II) concentration, reaction time, temperature, pH value, and coexisting ions were explored. At pH 7 and 303 K, the maximal adsorption capacity of OTCS for Pb(II) was 208.33 mg/g, which was greater than those of other adsorbing materials reported in the literature. The metal ion adsorption kinetics and isotherm models were found to obey pseudo-second-order kinetics and the Langmuir isothermal model, indicating that the adsorption process was monolayer chemisorption. The adsorption process could proceed spontaneously, and the thermodynamic results revealed that the adsorption mechanism was an endothermic reaction. The ion exchange and chelation between the sulfur, nitrogen and oxygen groups on the adsorbent and lead ions endowed the material with excellent adsorption properties. Significantly, OTCS showed excellent selectivity toward Pb(II). Therefore, the adsorbent OTCS is expected to promote the wider application of chitosan in the adsorption of Pb(II).

Kinetic study of Heavy Metal ion removal through Hydrogels

The crosslinkers allyl mannitol (AM), allyl sorbitol (AS) and allyl pentaerythritol (AP) have been used for the synthesis of crosslinked polymeric gels of acrylic acid. These gels were used for the removal of heavy metal ions from water. The quantitative removal of metal ions was determined with the support of UV-visible absorption spectroscopy. The results show that the fully dried hydrogel samples have better adsorption potential for heavy metal ion removal. The kinetics of metal ion adsorption during the treatment of wastewater has also been studied. It was found that under certain conditions, the kinetics involved may be of pseudo first order while under different set of conditions, the kinetics involved is of pseudo second order.

Potential of live Spirogyra sp. in the bioaccumulation of copper and nickel ions: A study on suitability and sustainability.

Various industrial and municipal wastes are the major sources of heavy metal contamination in water causing significant environmental issues. Bioremediation is an effective and affordable solution for the removal of metals and metal pollutants from industrial wastewater. This study aimed to assess the efficacy of live and dead Spirogyra sp. for sorption of metals like of Cu2+ and Ni2+ . The live Spirogyra sp. was used for the uptake of Cu2+ and Ni2+ from their aqueous solutions. The equilibrium data were fitted using a Langmuir and Freundlich isotherm model; the maximum uptakes for Cu2+ and Ni2+ were 29 and 521mgg-1 , respectively. Scanning electron microscopic (SEM) and infrared (IR) spectroscopic studies of Spirogyra sp. and treated Spirogyra sp. with specific metal ions were used to assess the bonding site and extent of sorption mechanism. The initial study showed that this biomass takes up a significant amount of metal ions. Compared to the Langmuir model, the Freundlich model showed better sorption process. The pseudo-second-order rate model represented an enhanced kinetics of metal ion adsorption using live Spirogyra sp. As bioaccumulation technology is environmental friendly and potentially cost-effective, live Spirogyra sp. is expected to be a good candidate for managing industrial wastewater.

A First Study of the Kinetics of Metal Ion Adsorption at Solid/Liquid Interface using Evanescent Wave-based Optical Microfiber

Although the use of chelating agent (CA)-functionalized optical microfiber (OM) for heavy metal ion sensing has been receiving tremendous research interest, a thorough study of the kinetics and adsorption of metal ions process which occurs at the solid/liquid interface has yet to be investigated. Kinetics and adsorption studies of metal ions, M2+ (i.e. Cd2+, Pb2+, and Zn2+) were carried out using CA-functionalized OM. The optically measured metal adsorption efficiency is interrelated to the properties of the chelating ligand, metal ion, and the molecular structure of the CA-M2+ complex that include the coordination number, bond length, and bond angle parameters. The kinetics adsorption chemistry of M2+ onto the CA-functionalized OM is well-fitted to the pseudo-first-order kinetic model. Moreover, this work also investigated the effects of the resultant optical evanescent field strength and the CA-M2+ structure towards the adsorption efficiency of OM with reduced tapered waist diameter. To the best of our knowledge, this is the first reported study to find this correlation in the metal adsorption efficiency at solid phase using an OM. The denouement of this study unveils a new physical chemistry insight of metal ion adsorption at the solid/liquid interface.

Removal and Preconcentration of Pb(II) Heavy Metal Ion from Water and Waste-Water Samples onto Poly (vinyl alcohol)/polyethyleneimine/Fe3O4 Microfibers Nanocomposite

In this research, poly (vinyl alcohol)/polyethyleneimine/Fe3O4 (PVA/PEI/Fe3O4) microfibers nanocomposite was synthesized in order to remove and/or preconcentrate Pb(II) ions. The microfibers nanocomposite was characterized by FT-IR, SEM, and XRD methods. The effects of various parameters such as pH, amount of adsorbent, and contact time on the adsorption efficiency of Pb(II) ions at the adsorbent were fully investigated and the optimum conditions were established. The adsorption capacity was found to be 370.9 mg g− 1 of the adsorbent. The kinetics of metal ions adsorption was evaluated using pseudo-first-order and pseudo-second-order models. The results showed that the adsorption of the investigated metal ion is in agreement with the pseudo first-order kinetics. The adsorption–desorption process was conducted for five cycles and the removal efficiency still kept 97% after three cycles.

Removal of Different Kinds of Heavy Metals by Novel PPG-nZVI Beads and Their Application in Simulated Stormwater Infiltration Facility

Polyvinyl alcohol and pumice synthetized guar gum-nanoscale zerovalent iron beads (PPG-nZVI beads) were synthesized, and their adsorption towards Pb2+, Cu2+, and Zn2+ ions was evaluated. The adsorption kinetics of metal ions was well fitted by the pseudo-second-order model. The adsorption rate decreased followed in the order of Cu2+ > Pb2+ > Zn2+, consistent with the reduction potential of the ions. The sorption isotherm was well fitted by Langmuir model. The maximum adsorption capacity decreased followed in the order of Pb2+ > Cu2+ > Zn2+, which suggested that the strength of covalent bonds between the metal ions and surface functional groups substituted to the beads is one of the major factors in the adsorption process. Adsorption increased with the increase of pH and the largest sorption occurred at pH 5.5, while ionic strength did not significantly influence the adsorption process. The application of PPG-nZVI beads as filling materials in the simulated stormwater infiltration facility shows good removal efficiency in treating the contaminated water containing Pb2+, Cu2+, Zn2+, Cr6+, and Cd2+ and the removal rate was more than 65% at least. The results indicated that the PPG-nZVI beads could be applied as promising sorbents for purification of heavy metal contaminated water.

Toxic heavy metal ion adsorption kinetics of Mg(OH)2 nanostructures with superb efficacies

Presence of both Cd(II) and Pb(II) ions in water is highly toxic for human health. That is why WHO recommends maximum permissible values of cadmium and lead in drinking water as 0.003 mg.L−1 and 0.01 mg.L−1, respectively. Therefore, here we report for the first time the adsorption kinetics of Mg(OH)2 for adsorptions of Pb(II) and Cd(II). To the best of our knowledge, this is the very first attempt to evaluate the Langmuir and Freundlich isotherms of Mg(OH)2 nanostructures with different morphologies for adsorptions of Pb(II) and Cd(II). The changes in adsorption processes with temperature are also studied. The Mg(OH)2 nanostructures reduce the concentration of Cd(II) ions from as high as 1000 mg.L−1 to as low as 0.001 mg.L−1 and that of Pb(II) ions from as high as 1000 mg.L−1 to as low as 0.009 mg.L−1. These values are much lower than the permissible limits prescribed by WHO. To attain these very significant achievements the time dependent changes in pore size, pore size distribution and surface area are explored. Finally, the results obtained by XRD, FTIR, Raman, pore size, pore size distribution, BET surface area, FESEM, TEM, EDX and adsoption kinetics studies show that nanoplatelet Mg(OH)2 powders exhibit the highest respective adsorption efficacies of 3700 mg.g−1 and 3030 mg.g−1 for Pb(II) and Cd(II). Thus, the nanoplatelet Mg(OH)2 powders may possibly find huge usage in near future for water purification applications.

Could Voltammetry be an Effective Alternative Technique to Study Adsorption Kinetics of Electroactive Metal Ions?

The suitability of LSV to study adsorption kinetics of metal ions was evaluated using Cu2+ adsorption on Amberlite® IR-120 as a model system. LSV provided results in agreement with conventional batch method with remarkable decreasing on analysis time and reagents consumption, since no adsorbent/adsorbate separation is required. Adsorption curves can be obtained in situ using only one portion of adsorbate solution. LSV provides higher temporal resolution for adsorption curves, which is indispensable to evaluate adsorption mechanisms and the performance of new adsorbent materials. Therefore, LSV not only saves time and reagents but also provides better quality of kinetic adsorption data.

Porphyrin-based electrostatically self-assembled multilayers as fluorescent probes for mercury(ii) ions: a study of the adsorption kinetics of metal ions on ultrathin films for sensing applications

ESAM as fluorescent probes for Hg(ii) ions were developed. The adsorption process involved in analyte-solid probe interaction was studied by monitoring fluorescence quenching.

Sorption of Heavy Metals by Ferralic-Arenosol and Vertic-Luvisol: A Comparative Isothermal Study

Modeling of sorption data is essential for characterizing retention of heavy metals by the soil matrices as well as to predict the fate of heavy metals in the environment. We carried out a study to evaluate adsorption characteristics of metallic ions (Cr3+, Pb2+ and Cu2+) as sole sorbates as well as in coexistence onto clay extracts of Vertic-Luvisol and Ferralic-Arenosol, the generally under-researched yet wide-spread semi-arid soils. Additionally, sorption kinetics of these heavy metals was evaluated in these soils. Equilibrium sorption data for both non-competitive and competitive metal systems were found to obey the Langmuir isotherm. Overall metal loading capacity was higher in Vertic-Luvisol than Ferralic-Arenosol whereas metal-wise affinity to binding sites favoured sorption of Cr3+ over Pb2+ and Cu2+ in that order. Contrary to the hypothesis of this study, the preferential sorption process was found to be driven by cationic properties as opposed to soil properties. Adsorption of metallic ions onto soils was significantly reduced in competitive systems than non-competitive systems, a phenomenon attributable to the antagonistic effects of coexisting species. Cr3+ suppressed sorption of Pb2+ and Cu2+ on both soils as validated by the competitive adsorption capacity ratios which were < 1 in all instances where Cr3+ coexisted with either one of Pb2+ or Cu2+. The adsorption kinetics of metal ions in both soils followed the pseudo-second-order rate law, suggesting chemical sorption as the rate-limiting step of the adsorption process.

Adsorption of Metal Ions onto the Chemically Modified Agricultural Waste

AbstractThis paper discusses about the adsorption of metal ions such as Cu(II), Cd(II), Zn(II), and Ni(II) from aqueous solution by sulfuric acid treated cashew nut shell (STCNS). The adsorption process depends on the solution pH, adsorbent dose, contact time, initial metal ions concentration, and temperature. The adsorption kinetics was relatively fast and equilibrium was reached at 30 min. The adsorption equilibrium follows Langmuir adsorption isotherm model. The maximum adsorption capacity values of the modified cashew nut shell (CNS) for metal ions were 406.6 mg/g for Cu(II), 436.7 mg/g for Cd(II), 455.7 mg/g for Zn(II), and 456.3 mg/g for Ni(II). The thermodynamic study shows the adsorption of metal ions onto the STCNS was spontaneous and exothermic in nature. The kinetics of metal ions adsorption onto the STCNS followed a pseudo‐second‐order kinetic model. The external mass transfer controlled metal ions removal at the earlier stages and intraparticle diffusion at the later stages of adsorption. A Boyd kinetic plot confirms that the external mass transfer was the slowest step involved in the adsorption of metal ions onto the STCNS. A single‐stage batch adsorber was designed using the Langmuir adsorption isotherm equation.

Carbon nanocages as heavy metal ion adsorbents

Heavy metal ion contamination in drinking water poses a major risk to human health, whilst contamination in wastewater streams can cause damage to the wider environment. In this study carbon nanocages, synthesised using a supercritical fluid deposition method, were examined as adsorbents of Pb 2+ ions from aqueous solutions. Through careful selection of the catalyst and the carbon deposition temperature and pressure, high yields of nanocages with surface areas up to 1175 m 2 g −1 were synthesised. These high surface area materials were subsequently tested for their ability to absorb Pb 2+ ions, as a function of pH, from simulated wastewater. The nanocages were found to be effective at removing the Pb 2+ ions at levels of 11.1 mg g −1, compared to 7.6 mg g −1 for commercially available activated carbon. The kinetics of metal ion adsorption by the nanocages and activated carbon can be described by a pseudo-second-order kinetics model, with a rate coefficient ( k 2) of 4.8 × 10 2 g mg −1 min −1.

Heavy Metal Removal from Water by Adsorption Using Pillared Montmorillonite

Removal of Cu2+, Cr3+ and Cd2+ from aqueous solutions by adsorption on montmorillonite modified by sodium dodecylsulfate (SDS) and hydroxy-alumino-silicate (HAS) was investigated. Experiments were carried out as a function of solution pH, solute concentration, and time. The Langmuir model was adopted to describe the single-solute adsorption isotherm, in which the Langmuir parameters were directly taken from those obtained in single-solute systems. The kinetics of metal ions adsorption was examined and the pseudo-first-order rate constant was finally evaluated.

Binary system Cu(II)/Pb(II) adsorption on activated carbon obtained by pyrolysis of cow bone study

Activated carbons obtained by pyrolysis of cow bone are economical adsorbents whose adsorption properties have been recently studied for monocomponent solutions of metal ions. However, for the wastewater treatment with these materials, their performance in multicomponent solutions has to be determined. This work studies adsorption competition between Cu 2+ and Pb 2+ metal ions. First, adsorption equilibrium for monocomponent metal ion solutions is investigated and shows adsorption capacities dependence on the two synthesized adsorbents; one of these adsorbents was obtained in an inert atmosphere (CBN) and the other one in the presence of the oxygen (CBOX). Differences in their textural properties may influence their adsorption capacities. Ionic size and electronegativity may also contribute to their adsorption behaviour. The second part of the study focuses on adsorption competition between those metal ions (a decrease in adsorption capacities is observed, whose value is related to adsorption kinetics of metal ions). Finally calorimetric measurements show good agreement with the earlier results.

Statistical Rate Theory Approach to Description of the pH-Dependent Kinetics of Metal Ion Adsorption

The influence of noncontrolled pH conditions on the kinetics of metal ion adsorption at solid/solution interfaces is studied by applying the SRT (statistical rate theory) approach. The quasi-equilibrium assumption inherent in SRT imposes the identical mathematical form of expressions for both the competitive adsorption and ion exchange models. However, they can be differentiated on the basis of a time-dependent profile of pH in the bulk solution. The developed model accounts for both multidentate binding mode and different proton/metal exchange ratios. Its applicability was shown by the quantitative analysis of the kinetic data reported by Choi and Yun.

Metal ion removal from aqueous solution using physic seed hull

The potential of physic seed hull (PSH), Jantropha curcas L. as an adsorbent for the removal of Cd 2+ and Zn 2+ metal ions from aqueous solution has been investigated. It has been found that the amount of adsorption for both Cd 2+ and Zn 2+ increased with the increase in initial metal ions concentration, contact time, temperature, adsorbent dosage and the solution pH (in acidic range), but decreased with the increase in the particle size of the adsorbent. The adsorption process for both metal ions on PSH consists of three stages—a rapid initial adsorption followed by a period of slower uptake of metal ions and virtually no uptake at the final stage. The kinetics of metal ions adsorption on PSH followed a pseudo-second-order model. The adsorption equilibrium data were fitted in the three adsorption isotherms—Freundlich, Langmuir and Dubinin–Radushkevich isotherms. The data best fit in the Langmuir isotherm indication monolayer chemisorption of the metal ions. The adsorption capacity of PSH for both Zn 2+ and Cd 2+ was found to be comparable with other available adsorbents. About 36–47% of the adsorbed metal could be leached out of the loaded PSH using 0.1 M HCl as the eluting medium.

Adsorption and Separation of Mercury: Sorption-Desorption of Hg2+ with Cross-Linked Graft Copolymer of Acrylic Acid and its Application in the Metal Ion Separation Process

A selective and reliable method has been developed for the extraction and separation of mercuric ion with cross-linked graft copolymer of acrylic acid based on sorption-desorption studies. The graft copolymer acts as an ion exchanger. The physico-chemical properties of the exchanger, and optimum pH, time, and temperature for Hg2+ adsorption were determined. Metal ion adsorption kinetics, isotherms, and thermodynamics have been studied. A plausible mechanism for mercury ion extraction has been suggested. Mercuric ion has been separated quantitatively from various synthetic mixtures containing metal ions (Ni2+, Cd2+, Pb2+, and Zn2+).

Synthesis of cross-linked poly(vinyl alcohol) and investigation of its efficiency in removing lead ion from aqueous solution

Cross-linked poly(vinyl alcohol) has been synthesized for the investigation of its efficiency in removing lead ion from aqueous solution. The physical and chemical nature of the synthesized ion exchange resin has been elucidated with the help of chemical test, FTIR, SEM, TGA and DSC. Particle size (0.25 mm), surface area (80.2 m 2 /g), ion exchange capacity (3.2 meq H + /g), optimum pH (4.5), time (60 min) and temperature (40 °C) for Pb II adsorption were determined. Metal ion adsorption kinetics, isotherms and thermodynamics have been studied.