Sorption Capacity For Ions Research Articles

Brewer's spent grain as a potential adsorbent of heavy metal ions from water

Application of biological materials for removing pollutants from water by adsorption is also known as biosorption, and such adsorbents as biosorbents. Advantages of biosorption over conventional methods are numerous, but the low price and availability of materials are basic criteria for the selection of potential biosorbents. Therefore, by-products of industry and agriculture are the subject of many scientific investigations. One of the most important by-products of brewing industry is the brewer's spent grain which is produced in large quantities throughout the whole year. As lignocellulosic material, brewer's spent grain have a certain sorption capacity for heavy metal ions which is examined in this paper. The results of batch adsorption experiments showed the best fit for Langmuir model, and the amount of adsorbed ions per unit of mass of adsorbent is in the range typical for this group of adsorbents. With the adsorption capacity of about 12 mg/g, brewer's spent grain proved to be potential biosorbent for practical application in the treatment of wastewater with concentrations of heavy metal ions higher than allowed.

Remediation of Some Selected Heavy Metals from Water Using Modified and Unmodified Mushrooms

The dispersal of toxic heavy metals by water from natural and anthropogenic is a worldwide environmental concern due to pollution. Despite some metals playing an important role in body, they are toxic when the level exceeds the tolerance limits while others such as lead have no known physiological value to human beings. Since heavy metals cannot be degraded, then their removal from drinking water is necessary. Mushrooms are readily available in Bomet County and their metal removal ability was investigated. The study aimed at removing heavy metals from water by adsorption using mushroom, as a cost-effective and sustainable method. The raw mushroom was modified with sodium hydroxide and characterization of both the parent material and its modified form was done using Fourier Transform Infrared spectrometry (FTIR). Sorption experiments were carried out using the batch adsorption method and sorption parameters including pH, contact time, adsorbent dose and initial metal ion concentration investigated. The results found out that the sorption capacity for cadmium ions ranged from 1.826- 25.285 mg/g by the unmodified edible mushroom (UEM), the modified edible mushroom (EM), unmodified toxic mushroom (UTM) and modified toxic mushroom (TM). For copper ions, sorption capacity ranged from 0.002-4.097 mg/g, while that of the lead ions ranged from 1.345-2.593 mg/g by the UEM, EM, UTM and TM respectively. The sorption capacity showed improvement on modification as sorption of cadmium increased from 1.826-25.285 mg/g by the UEM, EM, UTM and TM. At a pH range of 4-6, the sorbent material was found to remove up to 90% of the metals. The sorbent material had a removal efficiency of 95% of the metals in less than 20 minutes. The UEM and UTM fitted well in Langmuir adsorption isotherm model for cadmium and lead ions. For copper ions, UEM, EM, UTM and TM fitted in the Freundlich model. TM for lead ions best fitted in the Freundlich model. The bio-sorption kinetics was determined by fitting first-order-Lagergreg and Pseudo-second-order kinetics models to the experimental data. It was found that the data for lead was better described by the pseudo-second-order model. For copper ion, the data was best described by Ho’s pseudo second order for UEM and UTM, cadmium ions for all sorbents was best described by Lagergreg’s first-order kinetics. The FTIR analysis suggested the possibility of the participation of carboxyl groups in metal uptake. The levels of dissolved organic carbon (DOC) were found to be 19.0 mg/L in the raw material and 2.19 mg/L after modification. It was confirmed that modification minimized secondary pollution. This indicated that mushrooms have a potential application for the remediation of metal polluted waters.

RETRACTED: High sorption of U(VI) on graphene oxides studied by batch experimental and theoretical calculations

The graphene oxides (GOs) have been studied extensively in multidisciplinary areas owing to their excellent physicochemical properties. The high theoretical surface areas and large amounts of oxygen-containing functional groups at the basal planes and the edge sites ensure their high sorption capacity for heavy metal ions and radionuclides from large volumes of aqueous solutions. Herein, the GOs were applied as adsorbents to remove U(VI) from aqueous solutions at different experimental conditions, and the results showed that the sorption of U(VI) on GOs was strongly dependent on pH and was not affected by ionic strength obviously. The sorption capacity of U(VI) on GOs is calculated to be 1330 mg/g at pH 4.5 and T = 20 °C, which is much higher than any other today’s materials. The interaction mechanism of U(VI) on GOs was simulated by the computational DFT calculations, and the results evidenced that the variation in pH values led to significant changes in the circumstance of functional groups on GOs. As the pH value increased, the weak physical sorption/outer-sphere surface complexation between the GOs and U(VI) at low pH turned into strong chemical sorption/inner-sphere surface complexation with the negative charged –O− or –COO− groups induced by the deprotonation of the functional groups at high pH.

Ion-exchange recovery of nickel(II) and cobalt(II) from sulfuric acid solutions

Sorption recovery of nickel(II) and cobalt(II) in their joint presence in sulfuric acid solutions was studied on new samples of domestic ion exchangers of CYBBER brand. It was shown that the ion exchangers under study have a high sorption capacity for ions of both nonferrous metals, depending on the structure of a sorbent and on the acidity of a contacting solution. It was found that, after Co(II) and Ni(II) ions are extracted from weak or strong sulfuric acid solutions, they can be effectively eluted from the ion exchangers under study with a 2 M hydrochloric acid solution to an extent of 85–95% (nickel) and 87–95% (cobalt).

Simultaneous removal of NH4+, H2PO4− and Ni2+ from aqueous solution by thermally activated combinations of steel converter slag and spent alumina catalyst

Industrial wastes (spent alumina catalyst and steel converter slag) were utilized to prepare low-cost inorganic sorbents by thermal activation at temperatures ranging from 500 to 1000°C. According to the results of X-ray diffraction analysis, high-temperature thermal activation of mixtures of spent alumina catalyst and steel converter slag in different ratios leads to the formation of new crystalline phases. The Ni2+, H2PO4− and NH4+ sorption properties of the prepared samples were investigated in separate batch experiments, employing initial analyte concentration of 10mmolL−1. The steel converter slag samples calcined at 500°C and 900°C and the mixed sample (70% spent alumina catalyst and 30% steel converter slag) calcined at 1000°C exhibited maximum ion sorption capacities of 3.56mmol Ni2+ g−1, 3.28mmol H2PO4– g−1 and 2.21mmol NH4+ g−1, respectively. The principal mechanisms of Ni2+ sorption were the substitution of Ca2+ ions by Ni2+ ions, precipitation at high pH and sorption on Fe3O4 and SiO2 surfaces present in the samples. The H2PO4− sorption was due mainly to the formation of calcium phosphates and sorption on Fe2O3 and SiO2 surfaces, whereas the removal of NH4+ involved sorption on Al2O3 surfaces of the prepared samples. The results of the kinetics calculations showed that a second-order kinetic model offers a good fit for the present experimental data. The materials prepared from low-cost industrial wastes in this work have the ability to simultaneously remove NH4+, H2PO4− and Ni2+ ions from aqueous solution.

Removal of cadmium(II) and lead(II) ions from model aqueous solutions using sol–gel-derived inorganic oxide adsorbent

A study was conducted concerning the preparation and application of a novel synthetic oxide adsorbent of MgO-SiO2 type. The material was prepared via a sol–gel route, utilizing magnesium ethoxide and tetraethoxysilane as precursors of magnesium oxide and silica respectively, and ammonia as a catalyst. The powder was comprehensively analyzed with regard to chemical composition (EDS method), crystalline structure, morphology, characteristic functional groups, electrokinetic stability and porous structure parameters (BET and BJH models). The synthesized oxide adsorbent is amorphous, with irregularly shaped particles, a relatively large surface area of 612 m2/g, and negative surface charge over almost the whole pH range. Comprehensive adsorption studies were performed to investigate the adsorption of Cd(II) and Pb(II) ions on the MgO–SiO2 oxide adsorbent, including evaluation of adsorption kinetics and isotherms, the effect of pH, contact time and mass of adsorbent. It was shown that irrespective of the conditions of the adsorption process, the synthesized MgO–SiO2 adsorbent exhibits slightly better affinity to lead(II) than to cadmium(II) ions (sorption capacity of 102.02 mg(Pb2+)/g and 94.05 mg(Cd2+)/g). The optimal time for removal of the analyzed metal ions was 60 min, although adsorption reached equilibrium within 10 min for Pb(II) and within 15 min for Cd(II) ions, which was found to fit well with a type 1 pseudo-second-order kinetic model. Additionally, adsorption efficiency was affected by the pH of the reaction system—better results were obtained for pH ≥7 irrespective of the type of metal ion.

Synthesis of surface ion-imprinted magnetic microsphere for efficient sorption of perrhenate: A structural surrogate for pertechnetate

It is significant for environment and human health to develop new materials for the sorption of radioactive technetium. We report herein a novel method to synthesize surface ion-imprinted magnetic microspheres for efficient capture of technetium ions. Specifically, perrhenate anion as the structural surrogate for pertechnetate anion, was employed as template to prepare ion-imprinted magnetic microsphere by “one-pot” radical polymerization and quaternization. The sorption behavior is closely related with the surface chemical composition: the more nitrogen content, the higher sorption efficiency. The sorption is an exothermic spontaneous sorption process and kinetically followed pseudo-second-order model. A sorption capacity of 62.8mg of Re/g could be achieved at 298.15K and pH=6. Compared with non-imprinted composites, imprinted microspheres showed higher selectivity, faster kinetics, and larger sorption capacity of perrhenate ions. This work may provide a promising approach for the efficient sorption of pertechnetate.

Разработка метода получения карбокерамических адсорбентов на основе пористого углерода

Currently the world experiences a shortage of pure water, so the problems associated with water purification become most important. Increasingly stringent environmental requirements for water require the search for new environmentally friendly technologies. One of such techniques is based on the purification of water by adsorbent obtained from natural raw materials. The current situation in this area of research has caused the need to improve selective sorption technologies and treatment processes of contaminated fluids in order to address resource and environmental issues. In this work, carbon-ceramic sorbents were obtained from carbonized rice hull (CRH) and Tonkeris clay (from Tonkeris region, Kazakhstan) by activation with phosphoric acid (5% H3PO4) at a temperature 900-1200°C. Surface area, porosity, adsorption capacity of methylene blue and the sorption capacity for heavy metal ions of the obtained carbon-ceramic sorbents were studied. Optimum activation temperature of samples is 900°C. The sample containing 30% CRH has the highest mechanical strength.

Influence of hydrophobicity of alkyl sulfate and alkylpyridinium surfactants on the transport characteristics of plasticized polyvinyl chloride membranes

The ion transport of homologues of alkyl sulfate anions and alkylpyridinium cations through polyvinyl chloride filtration membranes (molecular sieves) under the conditions of diffusion mass transfer and direct current has been investigated. The quantitative characteristics of membrane transport, such as the permeability, diffusion, and partition coefficients; ion flux, selectivity, sorption capacity, and recovery, have been calculated. The effect of the hydrocarbon radical length of ionic surfactants on the quantitative characteristics of membrane transport has been revealed. It has been found that molecular sieves can be used for the separation of surfactant homologues.

Composite Beads Based on Chitosan and a Synthetic Polycation with Sorption Properties Modulated by the Cross‐Linking Strategy

SummaryA comparative study on the relation between the cross‐linking strategy and binding capacity of Cu2+, and Ni2+, of some novel composite beads based on chitosan (CS) and poly(vinylamine) (PVAm), is presented in the paper. The equilibrium sorption capacity of the metal ions onto the CS/PVAm composite beads was strongly depending on the cross‐linking strategy, and on the metal ion. Thus, the maximum sorption capacity values obtained by fitting the Langmuir isotherm on the data at 25 °C were 192.57 mg Cu2+/g, and 175.05 mg Ni2+/g, for the in‐situ cross‐linked beads, and 166.55 mg Cu2+/g, and 130.97 mg Ni2+/g, for the post‐cross‐linked beads.

Graft copolymerization of cellulose acetate for removal and recovery of lead ions from wastewater

In this study, cellulose acetate (CA) was modified by grafting with an equimolar binary mixture of acrylic acid (AA) and acrylamide (AAm) via radical polymerization technique using benzoyl peroxide as an initiator. Comparative studies between CA powder and modified CA [CA-g-(AA-co-AAm)] were investigated for Pb(II) ions removal and recovery from wastewater. The main operating conditions such as pH, concentration of Pb(II) ions and sorbent dose were also studied. Kinetic modeling has been studied and lead uptake capacity was calculated using the Langmuir, Freundlich and Dubinin–Kaganer–Radushkevich (DKR) models. The maximum sorption capacity (qemax) for Pb ions was only 9.4mg/g for unmodified CA, while, it was reached to 66.67mg/g by using modified CA. Spectroscopic analysis (FTIR), SEM, EDX and XRD analysis were investigated for CA and modified CA before and after recovery of lead ions from wastewater.

Effect of glutaraldehyde cross-linking degree of chitosan/sporopollenin microcapsules on removal of copper(II) from aqueous solution

Bio-based sorbents, especially cross-linked chitosan, have been widely used in heavy metal removal. Type of cross-linking agent and degree of cross-linking largely affect metal sorption behaviour of chitosan-based sorbents. This study describes the preparation of chitosan/sporopollenin (CS) microcapsules cross-linked with different amount of glutaraldehyde (GA)/chitosan ratios. The microcapsules were modified by the incorporation of 0.3, 0.9 and 1.5 mL of GA solution (in water 25% v:v) for 1.50 g of chitosan. A protected cross-linking method was used for the preparation of the CS/GA microcapsules by the reaction of the microcapsules with Cu(II) as the protector. Scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis were employed for the microcapsules characterization. The adsorption performance of the microcapsules was studied for the removal of Cu(II) at different concentration, contact time, amount of adsorbent, temperature and pH. The maximum Cu(II) removal values were 88.9, 100.4 and 80.7 mg g−1 by 0.3, 0.9 and 1.5 mL of GA impregnated CS microcapsules, respectively. The equilibrium adsorption isotherm data of the microcapsules exhibited a better fit to the Freundlich isotherm model. Affinity of the CS microcapsules for Zn(II), Cd(II), Ni(II) and Cr(III) in presence of Cu(II) was also investigated. GA/chitosan ratio affected the metal sorption performance and physicochemical properties of the microcapsules. The results revealed that CS microcapsules that were cross-linked with 0.9 mL of GA solution had better Cu(II) ion sorption capacity and can be cost-effective sorbents in water treatment.

Removal of Cd(II) and Cu(II) from aqueous solution using Bengal gram husk as a biosorbent

In the present work, Cicer arietinum husk (Bengal gram husk BGH) has efficiently been utilized for the removal of Cd(II) and Cu(II) from aqueous solutions. Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction and proximate analysis were used to analyse the biosorbent. Batch experiments were conducted to analyse as well as to evaluate the sorption capacity of metal ions. Factors affecting metal ions adsorption, such as contact time, pH, concentration ranges and adsorbent doses were studied. Maximum sorption of Cu(II) was found at pH 5, while for Cd(II), it was achieved at pH 7. From FTIR and NMR results, it has been found that in BGH, –OH group was present in abundance, and participated in metal complex formation in the sorption experiments. The biosorption process was fast enough because equilibrium reached at 120 min, following pseudo-second-order kinetics. The biosorption data fitted well in the Langmuir isotherm model, indicating the monolayer sorption. The maximum biosorption capacity of BGH, using Langmuir adsorption plots has been determined as 8.58 and 9.70 mg g−1 for Cd(II) and Cu(II), respectively.

Functional ligand anchored nanomaterial based facial adsorbent for cobalt(II) detection and removal from water samples

Ligand anchored functional nanomaterials are increasingly gaining interest as efficient materials for various types of toxic pollutants. In this study, the organic ligand of N,N′di(3-carboxysalicylidene)-3,4diamino-5-hydroxypyrazole was densely anchored onto the mesoporous silica by the building-block approach as facial adsorbent, characterized and then examined for the cobalt (Co(II)) ion detection and removal from aqueous solutions. The fixed-time approach was employed for analytical signal measurement in the detection operation. At optimum conditions, the calibration curve was linear in the range of 0.002–0.10mg/L Co(II) and the limit of detection was also achieved at 0.24μg/L. Moreover, the diverse ions did not show any significant absorbance intensity. Therefore, the established facial adsorbent provided a simple, rapid, cheap and sensitive method for Co(II) detection and could be used to detect Co(II) ions in the environment. This study also examined the possibility of using facial adsorbent to remove low concentrations of Co(II) ions from water solution. The sorption capacity was significantly affected by solution acidity, contact time and initial Co(II) ion concentration. The higher sorption capacity of the Co(II) ions was observed at higher pH regions. The sorption isotherms fit the Langmuir sorption model well and the maximum Co(II) ion sorption capacity was 157.73mg/g. The effective eluent of 0.20M HCl was used to elute the Co(II) from the facial adsorbent, and the adsorbent was simultaneously regenerated into the initial form after rinsing with water. The elution and regeneration showed that the adsorbent could be reused without significant losses of its initial properties even after 8 sorption–elution–reuse cycles. Therefore, the facial adsorbent could be used as a promising adsorbent for fast Co(II) ion detection and removal and might provide a simple and effective method for the treatment of water containing Co(II).

Chitosan/sporopollenin microcapsules: Preparation, characterisation and application in heavy metal removal

Use of natural polymers as biosorbents for heavy metal removal is advantageous. This paper reports a study aiming to design a novel biosorbent from two biomacromolecules; chitosan, a versatile derivative of chitin, and sporopollenin, a biopolymer with excellent mechanical properties and great resistance to chemical and biological attack. Chitosan/sporopollenin microcapsules were prepared via cross-linking and characterised by employing scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. Sorption performance of the microcapsules and the plain chitosan beads were tested for Cu(II), Cd(II), Cr(III), Ni(II) and Zn(II) ions at different metal ion concentration, pH, amount of sorbent, temperature and sorption time. The adsorption pattern followed Langmuir isotherm model and the sorption capacity of the chitosan/sporopollenin microcapsules was found to be Cu(II): 1.34, Cd(II): 0.77, Cr(III): 0.99, Ni(II): 0.58 and Zn(II): 0.71mmolg−1. Plain chitosan beads showed higher affinity for the ions; Cu(II): 1.46, Cr(III): 1.16 and Ni(II): 0.81mmolg−1 but lower for Cd(II): 0.15 and Zn(II): 0.25mmolg−1. Sporopollenin enhanced Cd(II) and Zn(II) ions sorption capacity of the chitosan microcapsules. Chitosan/sporopollenin microcapsules can be used in Cd(II) and Zn(II) metal removal.

Synthesis and metal ion sorption properties of peroxide-modified sodium titanate materials using a coprecipitation method

Peroxide-modified sodium titanate is synthesized by a coprecipitation method that uses titanium isopropoxide and sodium hydroxide precursors, with hydrogen peroxide as a mineralizer to modify the titanate to enhance actinide sorption. The mechanism and microstructure of the peroxide-modified titanate, synthesized using hydrogen peroxide at various pH values, and the effect on the sorption capacity of metal ions were studied. In the pH range of 8–9, the product experiences a highest weight loss of 34%, as well as the smallest sodium content and ion exchange capacity. In contrast, in the pH range of 6–7, the highest metal ion exchange ability is noted, up to 170mg/g. The pH value is crucial for the synthesis of peroxide-modified titanate materials.

Study of a new process for the efficient regeneration of ion exchange resins

Mixed bead resins comprising weakly acidic (carboxylic acid) and weakly basic (tertiary amine) groups were produced with properties similar to the thermally regenerable Sirotherm resin. This resin typically had a capacity of about 0.5mmol NaCl per gram and the sorption isotherm was found to be consistent with the Langmuir equation. The resin could be partially regenerated by heat (80%) and water washing (40%) as the ion sorption capacity was much reduced on heating to 80°C. However, the resin could be completely regenerated by a combination of heat and pre-washing with concentrated ammonium bicarbonate solution. On heating to 60°C or more the bicarbonate salt completely decomposes and can be removed from the resin as carbon dioxide and ammonia gases. These initial results suggest that this type of ion exchange resin could be used in a continuous process where the regeneration salt (ammonium bicarbonate) is thermally decomposed, collected and re-used to improve the efficiency of regeneration.

The properties of bentonites as a material for sorptive barriers

The mineral, grain size, and chemical compositions of bentonites and the cation-exchange capacity of their different genetic varieties are described with an estimation in static conditions of their sorption capacity for Cs and Sr ions. The compositions of betonites of different genetic types are correlated with their sorptive properties. The quantitative data on bentonites are compared with sorptive properties of loam that contains a low montmorillonite admixture.

Physicochemical characteristics and sorption capacities of heavy metal ions of activated carbons derived by activation with different alkyl phosphate triesters

Five alkyl phosphate triesters (APTEs), including trimethyl phosphate (TMP), triethyl phosphate (TEP), triisopropyl phosphate (TPP), tributyl phosphate (TBP) and trioctyl phosphate (TOP), were used as activating agents for preparing activated carbons (AC-APTEs) with high surface acidity and metal ion sorption capacity. N2 adsorption/desorption isotherms, surface morphologies, elemental compositions, results of Boehm's titration and sorption capacities of heavy metal ions of the carbons were investigated. AC-APTEs contained much more acidic groups and exhibited much less surface area (<500m2/g) in comparison with activated carbon (AC-PPA, 1145m2/g) obtained from phosphoric acid activation. For the AC-APTEs, AC-TOP had the highest surface area (488m2/g), AC-TMP showed the highest yield (41.1%), and AC-TBP possessed the highest acidic groups (2.695mmol/g), oxygen content (47.0%) and metal ion sorption capacities (40.1mg/g for Ni(II) and 53.5mg/g for Cd(II)). For the carbons, AC-APTEs showed much larger Ni(II) and Cd(II) sorption capacities than AC-PPA, except AC-TPP. The differences of the carbons in the physicochemical and sorption properties suggested surface chemistry of the carbons was the main factor influencing their sorption capacities whereas the pore structure played a secondary role.

Fructose and Urea as Precursors for N‐/O‐Modified Mesoporous Carbon with Enhanced Sorption Capacity for Heavy Metal Ions

AbstractOrdered mesoporous carbon with a high heteroatom (N, O) content was prepared by nanocasting from a melt of a eutectic mixture of fructose and urea (60/40 wt.‐%; melting temperature ca. 65 °C). These precursor compounds are cheap and environmentally friendly. The material possesses enhanced pore‐wall surface polarity as compared to that of mesoporous carbon prepared by the same technique without urea. This was verified by water sorption analysis. As a result, the heteroatom‐modified material shows higher sorption capacity for the uptake of heavy metal ions (Cu2+) from aqueous solution, which may be interesting for potential application in wastewater cleaning.