Biosorption of Ni(II) from electroplating wastewater by modified (Eriobotrya japonica) loquat bark

Biosorption of nickel ions from aqueous solutions by modified loquat bark waste (MLB) has been investigated in a batch biosorption process. The biosorbent MLB was characterized by FTIR analysis. The extent of biosorption of Ni(II) ions was found to be dependent on solution pH, initial nickel ions concentration, biosorbent dose, contact time, and temperature. The experimental equilibrium biosorption data were analyzed by three widely used two-parameters Langmuir, Temkin and Freundlich isotherm models. Langmuir and Temkin isotherm models provided a better fit with the experimental data than Freundlich isotherm model by high correlation coefficients R². The maximum adsorption capacity was 27.548 mg/g of Ni(II) ions onto MLB. The thermodynamic analysis indicated that the biosorption behavior of nickel ions onto MLB biosorbent was an endothermic process, resulting in higher biosorption capacities at higher temperatures. The negative values of ΔG° (−5.84 kJ/mol) and positive values of ΔH° (13.33 kJ/mol) revealed that the biosorption process was spontaneous and endothermic. Kinetic studies showed that pseudo-second order described well the biosorption experimental data. The modified loquat bark (MLB) was successfully used for the biosorption of nickel ions from synthetic and industrial electroplating effluents.     

Equilibrium,kinetic and thermodynamic biosorption studies of Hg(II) on red algal biomass of Porphyridium cruentum

Among a variety of microbial materials employed for biosorption, algae have added advantages of non-toxic and autotrophic nature. In this study, biosorption of Hg(II) was studied with red algal biomass of Porphyridium cruentum. The parameters affecting biosorption such as dosage of biosorbent, pH, contact time, initial metal concentration, temperature and effect of foreign metal cations in binary system were evaluated. Kinetic data were described with the help of pseudo-first-order and pseudo-second-order kinetic models. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models were applied to adsorption equilibrium data. According to the results, the maximum removal capacity (q_max) was 2.62?mg/g observed at pH 7 with 0.25?g/L of biosorbent dosage for Hg(II) solution containing 10?mg/L of metal ions. The Langmuir isotherm model fits best to the adsorption data while the kinetic data followed the pseudo-second-order model. Thermodynamics studies showed that the biosorption process of Hg(II) on P. cruentum was exothermic in nature.     

Using xanthated Lagenaria vulgaris shell biosorbent for removal of Pb(II) ions from wastewater

Chemically modified Lagenaria vulgaris shell was applied as a new sorbent for the removal of lead (II) ions from aqueous solution in a batch process mode. The influence of contact time, initial concentration of lead (II) ions, initial pH value, biosorbent dosage, particle size and stirring speed on the removal efficiency was evaluated. Biosorbent characterization was performed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Four kinetic models (pseudo-first order, pseudo-second order, Elovich model and Intraparticle diffusion model) were used to determine the kinetic parameters. The experimental results were fitted to the Langmuir, Freundlich, Dubinin–Radushkevich and Temkin models of isotherm. Pseudo-second order kinetic model and Langmuir isotherm model best fitted the experimental data. Sorption process is obtained to be fast and equilibrium was attained within 40 min of contact time. The maximum sorption capacity was 33.21 mg g^?1. Biosorption was highly pH-dependent where optimum pH was found to be 5. The results of FTIR and SEM analysis showed the presence of new sulfur functional groups. This study indicated that xanthated Lagenaria vulgaris shell could be used as an effective and low-cost biosorbent for the removal of lead (II) ions from aqueous solution.     

Biosorption of radiostrontium by alginate beads: application of isotherm models and thermodynamic studies

Radioactive strontium is one of the major radioactive contaminant and its contamination is a very serious concern. Therefore, there is a need for economic, effective, non-toxic, readily available and abundant adsorbent or biosorbent to remove strontium from solutions. In this study, biosorption of ⁸⁵Sr as a surrogate for ⁹⁰Sr onto alginate beads was investigated in a batch system. Alginate beads were prepared from Na-alginate via cross-linking with divalent calcium ions according to the egg box model. The effect of several parameters such as pH, initial strontium concentration, contact time, dosage of alginate beads and temperature were investigated. In order to optimize the design of biosorption system for the removal of strontium, it is important to establish the most appropriate correlation for equilibrium curves. The experimental isotherm data were described by 6 different biosorption isotherm models, namely Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, Flory–Huggins and Brunauer, Emmer and Teller, with constants obtained from linear and non-linear regression methods. The thermodynamic parameters (?H°, ?S° and ?G°) for strontium biosorption were also determined. The results indicate that these alginate beads have a good potential for the biosorption of strontium from solutions.     

Ammonium salt of the cross-linked maleic acid–allylpropionate–styrene terpolymer as effective sorbent for removal of Cu2+ ions from water solutions (sorption of the copper ions)

The capability of the ammonium salt of the cross-linked maleic acid–allylpropionate–styrene terpolymer for the adsorption of Cu²⁺ from aqueous solutions was examined. Effect of the various experimental parameters on removal degree of the copper ions was investigated. Equilibrium data were fitted to the Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin isotherm models. Kinetics studies suggested that the adsorption allowed pseudo-second-order reaction. The negative values of ΔG° and the positive value of ΔH° indicate that the sorption process is spontaneous and endothermic in nature. The positive value of ΔS° shows the increasing randomness during adsorption process. Considering the FTIR and UV–vis spectra of the sorbent after sorption, it is concluded that Cu²⁺ enters a complex with carboxylate and ester groups of the sorbent.     

Removal of Cu(II), Cd(II) and Cr(III) ions from aqueous solution by dam silt

The removal of heavy metals, such as Cu(II), Cd(II) and Cr(III) from aqueous solution was studied using Chorfa silt material (Mascara, Algeria). The main constituents of silt sediment are quartz, calcite and mixture of clays. The experimental data were described using Freundlich, Langmuir, Dubinin–Radushkevich (D–R) and Langmuir–Freundlich models. The adsorbed amounts of chromium and copper ions were very high (95% and 94% of the total concentration of the metal ions), whereas cadmium ion was adsorbed in smaller (55%) amounts. The Langmuir–Freundlich isotherm model was the best to describe the experimental data. The maximum sorption capacity was found to be 26.30, 11.76 and 0.35 mg/g for Cr³⁺, Cu²⁺ and Cd²⁺, respectively. The results of mean sorption energy, E (kJ/mol) calculated from D–R equation, confirmed that the adsorption of copper, chromium and cadmium on silt is physical in nature.     

Evaluation of Acacia nilotica as a non conventional low cost biosorbent for the elimination of Pb(II) and Cd(II) ions from aqueous solutions

In the present study a biomass derived from the leaves of Acacia nilotica was used as an adsorbent material for the removal of cadmium and lead from aqueous solution. The effect of various operating variables, viz., adsorbent dosage, contact time, pH and temperature on the removal of cadmium and lead has been studied. Maximum adsorption of cadmium and lead arises at a concentration of 2 g/50 ml and 3 g/50 ml and at a pH value of 5 and 4, respectively. The sorption data favored the pseudo-second-order kinetic model. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were applied to describe the biosorption isotherm of the metal ions by A. nilotica biomass. Based on regression coefficient, the equilibrium data found were fitted well to the Langmuir equilibrium model than other models. Thermodynamic parameters such as free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) have been calculated, respectively revealed the spontaneous, endothermic and feasible nature of adsorption process. The activation energy of the biosorption (Ea) was estimated as 9.34 kJ mol⁻¹ for Pb and 3.47 kJ mol⁻¹ for Cd from Arrhenius plot at different temperatures.     

Sorption of thallium(III) ions from aqueous solutions using titanium dioxide nanoparticles

Titanium dioxide nanoparticles (NPs) were employed for the sorption of Tl(III) ions from aqueous solution. The process was studied in detail by varying the sorption time, pH, Tl(III) concentration, temperature, and amount of sorbent. The sorption was found to be fast and to reach equilibrium within 2 min, to be less efficient at low pH values, and to increase with pH and temperature. The sorption fits the Langmuir equation and follows a pseudo second order model. The mean energy of the sorption is approximately 15 kJ mol^?1 as calculated from the Dubinin–Radushkevich isotherm. The thermodynamic parameters for the sorption were also determined, and the ΔH ⁰ and ΔG ⁰ values indicate endothermic behavior.     

Thermodynamics and kinetics of adsorption of Cu(II) from aqueous solutions onto multi-walled carbon nanotubes

Release of heavy metals into water as a result of industrial activities may pose a serious threat to the environment. The objective of this study is to assess the uptake of Cu²⁺ from aqueous solutions onto multi-walled carbon nanotubes (MWCNT). The potential of the t-MWCNT to remove Cu²⁺ cations from aqueous solutions was investigated in batch reactor under different experimental conditions. The processing parameters such as initial concentration of Cu²⁺ ions, temperature, and adsorbent mass were also investigated. Copper uptake was quantitatively evaluated using the Langmuir, Freundlich and Dubinin–Kaganer–Radushkevich (DKR) models. In addition, the adsorption equilibrium was described well by the Langmuir isotherm model with maximum adsorption capacity of 12.34 mg/g of Cu²⁺ cations on t-MWCNT. Various thermodynamic parameters, such as ΔG⁰, ΔH⁰ and ΔS⁰ were calculated. The thermodynamics of Cu²⁺ cations adsorption onto t-MWCNT system pointed at spontaneous and endothermic nature of the process. Using the second-order kinetic constants, the activation energy of adsorption (E_a) was determined as 27.187 kJ/mol according to the Arrhenius equation.     

Efficiency of Acacia Gummifera powder as biosorbent for simultaneous decontamination of water polluted with metals

Biosorbent materials represent an interesting alternative to classic methods of metal removal from industrial effluents. Acacia biomass showed a higher absorption capacity for heavy metals than living biomass. This study aimed to evaluate the bioadsorption of Lead and Cadmium onto Acacia Gummifera gum, using batch experiment. The structural characterization of the biosorbent was carried out using FT-IR, SEM, BET, TGA and DSC analysis. The adsorption equilibrium was reached within 15 min. A maximum uptake of 18.3 mg.g⁻¹ Pb²⁺ and 9.57 mg.g⁻¹ Cd²⁺ was achieved at pH 6.5. The metal ions seemed to be removed exclusively by ion exchange, physical sorption and chelation. The biomass of A. Gummifera powder was found to be effective for lead and cadmium removal with respectively 97% and 86% sorption efficiency at a concentration of 100 mg/L, in aqueous media. Parameters affecting adsorption capacities such as biosorbent dosage, initial metal concentration, temperature, and pH are discussed in detail. Furthermore, adsorption thermodynamics, kinetics, and equilibrium were studied and fitted by different models. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms were used to compare adsorption data at equilibrium. The adsorption kinetics data were found to be best fitted by the pseudo-second-order model, and the adsorption isotherm was well fitted with the Langmuir model. The calculated thermodynamic parameters (ΔG⁰, ΔS⁰ and ΔH⁰) indicated a spontaneous and exothermic biosorption of both metal ions onto Acacia Gummifera. Moreover, chromatograms obtained by size exclusion chromatography coupled with multi-angle laser light scattering detection system (SECMALLS) showed the formation of complexes between the arabinogalactan-peptide (AGP) and glycoprotein (GP) Acacia moieties and the two studied metal ions. The analysis of the FTIR spectra of dried Acacia and that of Acacia loaded with lead and cadmium in aqueous media suggests that the surface functional groups such as amides and carboxy groups might be involved in the metal removal process.The extent of adsorption for both metals increased along with an increase of the A. Gummifera biomass dosage. A. Gummifera biomass, which is safe, of low-cost, and highly selective, seems therefore to be a promising substrate for simultaneous trapping of Pd and Cd ions in aqueous solutions.     

Biosorption of Pb(II) and Cd(II) ions by Agave sisalana (sisal fiber)

The present work proposes the use of Agave sisalana (sisal fiber) as an natural adsorbent for ions Pb(II) and Cd(II) biosorption from natural waters. The flame atomic absorption spectrometry was used for quantitative determination and study of the ions Pb(II) and Cd(II) adsorption on the solid phase. The Fourier transform infrared spectroscopy (FT IR) was used to investigate the sisal structure and the specific BET surface area was analyzed. The biosorption potential of sisal as biosorbent for the removal of the ions Pb(II) and Cd(II) from aqueous solution was investigate considering the followings parameters: pH, biomass amount and contact time. Langmuir and Freundlich isotherms were used to evaluate adsorption behavior of the ions on this solid phase. The results showed that sisal has a surface area to adsorption of 0.0233 m² g^{− 1}, and the OH and CO functional groups are the main involved in the biosorption. The best interpretation for the experimental data was given by Freundlich isotherm that proposes a monolayer sorption with a heterogeneous energetic distribution of active sites, accompanied by interactions between sorbed molecules. The maximum monolayer biosorption capacity was found to be 1.85 mg g^{− 1} for Cd (II) and 1.34 mg g^{− 1} for Pb (II) at pH 7 and 296 K. This phase solid can be used for biosorption of cadmium and lead in polluted natural waters.     

Adsorption of Pb(II) and Ni(II) From Aqueous Solution by a High-Capacity Industrial Sewage Sludge-Based Adsorbent

In the present study, adsorption of Ni(II) and Pb(II) from aqueous solution was investigated using activated carbon synthesized with industrial wastewater sludge. The synthesized adsorbent was analyzed using nitrogen adsorption–desorption and Fourier transfer infrared (FTIR) techniques. Batch adsorption mode was used to evaluate the effect of solution pH, contact time, adsorbent dose, initial metal ion concentration, and temperature on the adsorption capacity of the synthesized adsorbent. The kinetic data were analyzed using different kinetic models. The pseudo-second-order equation gave the best fit to the experimental data for both metal ions. The equilibrium isotherm data were analyzed using the Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) isotherm models. The results showed that the data obtained for the Ni(II) and Pb(II) adsorption are in good agreement with the Langmuir model. The Langmuir mono-layer maximum adsorption capacities for Ni(II) and Pb(II) ions were estimated to be 74.06 and 88.76 mg g^?1 at 25°C, respectively. In addition, the thermodynamic studies proved that the adsorption process of both metals could be considered endothermic.     

Biosorption of reactive dye from aqueous media using Saccharomyces cerevisiae biomass. Equilibrium and kinetic study

The biosorption Brilliant Red HE-3B reactive dye by nonliving biomass, Saccharomyces cerevisiae, in batch procedure was investigated. Equilibrium experimental data were analyzed using Freundlich, Langmuir and Dubinin — Radushkevich isotherm models and obtained capacity about 104.167 mg g^?1 at 20°C. The batch biosorption process followed the pseudo-second order kinetic model. The multi-linearity of the Weber-Morris plot suggests the presence of two main steps influencing the biosorption process: the intraparticle diffusion (pore diffusion), and the external mass transfer (film diffusion). The results obtained in batch experiments revealed that the biosorption of reactive dye by biomass is an endothermic physical-chemical process occurring mainly by electrostatic interaction between the positive charged surface of the biomass and the anionic dye molecules. The biosorption mechanism was confirmed by FT-IR spectroscopy and microscopy analysis      

Effect of environmental conditions on 109Cd(II) sorption to MnO2

The sorption of Cd(II) from aqueous solution on MnO₂ was investigated under ambient conditions. Experiments were carried out as a function of contact time, solid content, pH, ionic strength, foreign ions, fulvic acid and temperature. The results indicated that the sorption of Cd(II) was strongly dependent on pH and ionic strength. At low pH, the sorption of Cd(II) was dominated by outer-sphere surface complexation and ion exchange with Na⁺/H⁺ on MnO₂ surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. The Langmuir, Freundlich and Dubinin–Radushkevich models were used to simulate the sorption isotherms at three different temperatures. The thermodynamic data (ΔG ⁰, ΔS ⁰, ΔH ⁰) calculated from the temperature dependent sorption isotherms suggested that the sorption of Cd(II) on MnO₂ was an spontaneous and endothermic process.     

Study on the characterization of lead (II) biosorption by fungus <Emphasis Type="Italic">Aspergillus parasiticus</Emphasis>

The lead (II) biosorption potential of Aspergillus parasiticus fungal biomass has been investigated in a batch system. The initial pH, biosorbent dosage, contact time, initial metal ion concentrations and temperature were studied to optimize the biosorption conditions. The maximum lead (II) biosorption capacity of the fungal biosorbent was found as 4.02 × 10⁻⁴ mol g⁻¹ at pH 5.0 and 20°C. The biosorption equilibrium was reached in 70 min. Equilibrium biosorption data were followed by the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. In regeneration experiments, no significant loss of sorption performance was observed during four biosorption-desorption cycles. The interactions between lead (II) ions and biosorbent were also examined by FTIR and EDAX analysis. The results revealed that biosorption process could be described by ion exchange as dominant mechanism as well as complexation for this biosorbent. The ion exchange mechanism was confirmed by E value obtained from D-R isotherm model as well.     

Kinetics and Equilibrium Models for Sorption of Cu(II) onto a Novel Manganese Nano-adsorbent

The studies of kinetics and equilibrium sorption of Cu(II) were undertaken using nanoscale zerovalent manganese (nZVMn) synthesized by chemical reduction in a single pot system. nZVMn was characterized using scanning electron microscopy, energy dispersive x-ray, and surface area determined by Brunauer–Emmett–Teller. The effect of pH, contact time, adsorbent dose, agitation speed, initial Cu(II) concentrations, temperature, and ionic strength on the sorption of Cu(II) onto nZVMn were investigated in a batch system. The kinetic data followed pseudo-second-order. The mechanism was governed by pore diffusion. The equilibrium sorption data were tested by Freundlich, Langmuir, Temkin, Dubinin–Kaganer–Raduskevich, and Halsey isotherm models. The Langmuir monolayer adsorption capacity (Q_max = 181.818 mg/g) is much greater compared to other nano-adsorbents used in sorption of Cu(II). The thermodynamic parameters (ΔH⁰, ΔS⁰, ΔG⁰) revealed a feasible, spontaneous, and endothermic adsorption process. nZVMn has a great potential for effective removal of copper (II) in aqueous solution.     

Insight from adsorption properties of Xylidyl Blue embedded hydrogel for effective removal of uranyl: Experimental and theoretical approaches

Applications of a hybrid material consisting of polyacrylamide (PAA) and Xylidyl Blue (XB) for the removal of uranyl ions from aqueous solutions has been investigated with all details. Adsorption experiments were performed at batch mode and constant temperature. Experimental parameters affecting adsorption process such as pH, initial uranyl concentration, time and temperature were studied on the removal of the uranyl ions. The isotherms assays were carried out with synthetic solutions and adsorption data were evaluated by using Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models. Morphological and chemical characterizations of new synthesized material were investigated by UV-VIS-NIR spectroscopy and SEM/EDX techniques and pH_pzc experiments. The results of the kinetic experiments are consistent with pseudo-second-order models and intra-particle diffusion models with a slightly better fit to the latter. Equilibrium was achieved within 3 h. The value of rate constant for adsorption process was calculated as 1.055 mol⁻¹ kg min⁻¹ at 318 K. The calculated thermodynamic parameters (ΔG°, ΔH° and ΔS°) indicated that the adsorption of uranyl ions onto XB@PAA was feasible, spontaneous and endothermic nature under the studied temperature. The developed material has also a potential as a sensor because its color turn from pink to red by adsorption of uranyl ions.     

Removal of Th(IV) ions from aqueous solution using bi-functionalized algae-yeast biosorbent

Composites could be more effective adsorbents than inorganic and organic components individually. In the present study, the red macro marine algae, Jania Rubens and yeast, Saccharomyces cerevisiae immobilized on silica gel were used as a constituent of bi-functionalized biosorbent to remove thorium ions from aqueous solution. Optimum biosorption conditions were determined as a function of pH, initial Th(IV) concentration, contact time, temperature, volume/mass ratio and co-ion effect. The morphological analysis of the biocomposite was performed by the scanning electron microscopy and functional groups in the biosorbent were determined by FT-IR spectroscopy. In order to find the adsorption characteristics, Langmuir, Freundlich, and Dubinin–Radushkevich adsorption isotherms were applied to the adsorption data. The data were well described by Langmuir adsorption isotherms while the fit of Freundlich adsorption isotherms and Dubinin–Radushkevich equation to adsorption data was poor. Using the equilibrium constant value obtained at different temperature, the thermodynamics properties of the biosorption (ΔG°, ΔH° and ΔS°) were also determined. The results show that biosorption of Th(IV) ions onto biocomposite was exothermic nature, spontaneous and more favorable at lower temperature under examined conditions.     

Diffusion Mechanisms of Biosorption of Cr(VI) onto Powdered Cotton Stalk

The present study investigates biosorption diffusion mechanism for the removal of toxic hexavalent chromium from aqueous solution using powdered cotton stalk an agricultural waste biomass. The effects of pH, temperature, adsorption isotherms, adsorption kinetics, and thermodynamic on chromium biosorption were investigated. The results showed that a maximum removal efficiency of 95% was achieved at pH 2. The pH at zero point charge (pH_zpc) on biosorbent surface was 4.3. The adsorption kinetics showed that the pseudo-second order rate expression fitted well the biosrption process. The equilibrium isotherm was measured experimentally and results were analyzed by Langmuir, Freundlich, and Temkin isotherms using linearized correlation coefficients. The significant parameters for isotherms were determined. The Langmuir adsorption isotherm relative to two other isotherms was found to fit the equilibrium data best for chromium adsorption. Thermodynamic studies reveal that the biosorption of Cr(VI) on cotton stalk was endothermic, spontaneous and occurs with increase in disorder at solid-liquid interface. Adsorption diffusion kinetic was further analyzed and showed that biosorption mechanism was totally controlled by intraparticle diffusion mechanism.     

Radiometric analysis of <Superscript>90</Superscript>Sr in fish bone ash samples by liquid scintillation counting after separation by extraction chromatographic resin

Studies on the extraction behavior and immobilization of cadmium by greener reagents have important bearings in today’s science. No-carrier-added (NCA), ¹⁰⁹Cd radionuclide is a potential candidate towards radiopharmaceutical studies for both in vivo and in vitro applications and is also used in industrial and environmental studies. Herein, we have studied the adsorption and desorption characteristics of cadmium in both NCA and bulk concentrations into calcium alginate using radiochemical method. Various isotherms like Langmuir, Freundlich, Temkin and Dubinin–Radushkevich have been studied and compared to match the adsorption phenomenon. A spontaneous endothermic physisorption process is expected from thermodynamic parameters.