Spherical Carbon Adsorbents Research Articles

In-situ magnetization of porous carbon beads for lithium-ion adsorption from strongly acidic solution

To enhance the feasibility and cost-effectiveness of hydrometallurgy of spent lithium-ion batteries, it is crucial to achieve the recycling of strong acids employed in electrode dissolution. The current method of directly adding precipitants into strongly acidic electrode filtrate to obtain lithium results in contamination and renders it non-reusable. Therefore, an adsorption method was proposed for the capture and adsorption of lithium-ion from a strongly acidic solution. Subsequently, the porous, magnetic, and spherical carbon adsorbents were used for magnetic separation after reaching saturation during the adsorption process. In this work, the porous carbon beads were prepared using coal tar pitch as a precursor material, and the different magnetization methods of as-prepared carbon beads were investigated, including in-situ and impregnated magnetization. The results demonstrate a significant increase in mesopore volume from 0.0610 cm3/g to 0.2120 cm3/g by in-situ magnetization, thereby enhancing the availability of transport channels for lithium-ion adsorption. The graphitization degree of porous carbon beads is improved by magnetization, which is attributed to the catalytic graphitization effect of Fe. The ID/IG value of porous carbon beads decreases the most from 2.68 to 2.48 by impregnated magnetization, while the content of iron retained after activation is low, and the remanent magnetism of PCB-FeCl3 is far less than that of PCB-Fe3O4 (25.1103 emu/g). The result implies that the in-situ magnetization technique enables the utilization of porous carbon beads for magnetic separation recovery technology. The in-situ magnetized porous carbon beads have a high adsorption capacity for lithium-ion (79.8 mg/g) and still maintain excellent adsorption performance after 5 cyclic times of lithium-ion adsorption from a strongly acidic solution.

Energy Efficient Technology for Processing Fine-grained Carbonaceous Wastes into Spherical Carbon Adsorbents

The technical and technological processing features of fine-grained carbonaceous technological waste into environmentally friendly products with significant energy and resource saving were introduced. The article defines products which are the recycled highly efficient and competitive spherical activated carbons produced by high-speed pelletisation in aqueous medium with various hydrocarbon binders. The article describes the step-by-step manufacturing of spherical pellets by high-speed components mixing in aqueous medium. The main production parameters of spherical activated carbons (SAC) from the introduced raw materials, the formulation (ratio of components), the conditions for pelletisation and subsequent high-temperature carbonization and activation were identified. The parameters of the porous structure, sorption properties and technical features of the obtained materials were assessed according to the methods typical for the validation of activated carbons. It was confirmed that the characteristics of developed SAC were not inferior to industrial activated carbons in terms of porous structure and sorption properties, and significantly exceed them in terms of percentage of ash and endurance capability.

Effect of mesoporous characteristics on competitive adsorption kinetics of uremic-like toxin and atorvastatin on spherical carbon adsorbents for an in vitro chronic renal failure therapeutic model

Indole-3-acetic acid (IA, urine-like toxin) coexisting with atorvastatin (AT) was adsorbed by spherical carbonaceous adsorbents (SCs). The relationship between the competitive adsorption kinetics and the mesoporous structures was investigated. The pore structures of the four SCs were analyzed using the Hg and gas adsorption methods. SC adsorption tests were performed using the dissolution test with the paddle method with an SC sample in distilled water containing IA and/or AT at 37.0 °C. The amounts of IA and AT adsorbed on SCs in single- and binary-drug administration tests were measured based on the ultraviolet-visible spectra using classical least squares analysis. Rate constants for the drug adsorption of IA and AT by SCs (kIA and kAT, respectively) were suppressed by the effect of coexisting drugs. The suppression of IA adsorption by the coexisting drug was dependent on the pore structure of the SCs. kIA and kAT against the SCs were competitively inhibited by coexisting drugs.

Spherical Mesoporous Carbon Adsorbents for Sorption, Concentration, and Extraction of Nicotine and Other Components of Cigarette Smoke

Spherical carbon adsorbents have been synthesized with introduction of mesoporous MCM-48; their adsorption activity towards toxic components of cigarette smoke including nicotine has been studied with the purpose of application as fillers for filters in smoking rooms. The structure-sorption properties of the surface, as well as the composition of the surface layer of the carbon material, have been examined by means of low-temperature adsorption/desorption of nitrogen, X-ray photoelectron and IR-spectroscopy, and pH- and conductometric titration. It has been demonstrated that upon carbonization and activation the surface layer of the synthesized carbon adsorbents contained protolytically active carboxyl (0.1; 0.35 mmol/g) and hydroxyl groups, as well as a wide range of other oxygen-containing groups. The synthesized material has demonstrated a narrow pore size distribution (5–9 nm), while micropores were virtually absent. It has been established that the spherical mesoporous activated carbon synthesized in the present study with having a developed specific surface area of 1680 m2/g and the sorption capacity towards nicotine of 9.2 mmol/g has demonstrated superior properties exceeding those of the commercially produced material. Total chemical regeneration of the adsorbents (up to five to seven cycles) has been achieved through extraction by organic solvents (chloroform or methanol) without subsequent thermal treatment. Interaction of gaseous products of cigarettes burning with the spherical carbon samples occurred throughout the whole volume and not only on the external surface. It has been demonstrated that the investigated adsorbents can be applied in both stationary smoking rooms and cabins equipped with autonomous ventilation.

Synthesis of spherically shaped granulated carbon sorbent

New technological procedure for obtaining spherical carbon sorbents was considered. The method is based on oil granulation in the technology of coal benefication. The coal dust of 2SS brand and coal tar were used to obtain spherical activated carbons with high sorption and strength characteristics. The influence exerted by the introduction of surfactants in the course of molding on the quality parameters of activated carbons was examined. The basic physicochemical and sorption characteristics of the carbons being developed were analyzed and it was shown that spherical carbon adsorbents with micropore volume of up to 0.31 cm3 g–1 and abrasion strength of up to 91% can be obtained.

Properties of novel spherical carbon adsorbents synthesized from phosphorylated polymeric precursors

Phosphorus-containing carbon adsorbents have been prepared by the carbonization and CO2 activation of two sets of submicroporous phosphorylated styrene/divinylbenzene copolymers in various (H+, Cs+, Cu2+, Co2+ and Fe3+) ionic forms. These copolymers have been synthesized in the form of beads, using the suspension polymerization technique. The polymerization was carried out in the presence of heptane and toluene in order to obtain porous material and polymers were subsequently subjected to phosphorylation. The content of the phosphinic groups in the modified polymers is ca. 4mmol/g. Thermal degradation of the polymer precursors was monitored using thermogravimetric analysis. It was found that the carbonization yield is ca. 20% for the phosphinic acid forms and reaches ca. 60% for the various phosphinic acid salts. Scanning electron microscopy (SEM) was used to investigate the structure of the obtained carbon adsorbents. The metal ion in the phosphinic acid salt and porous structure of polymeric precursor determine the morphology and mechanical strength of the obtained carbon grains. Chemical composition were investigated using XPS, XRD and pH titrations methods. The characteristics of the porous structure of the polymer precursors and carbon materials were obtained by benzene and CO2 adsorption. The resultant carbon adsorbents are predominantly microporous and their specific surface area is in the range of 300–1500m2/g depending on the ionic form and the porosity of polymeric precursors.

Adsorption kinetic and mechanistic studies for pharmaceutical spherical carbon adsorbents: Comparison of a brand product and two generics

The kinetic and mechanistic profiles of three pharmaceutical spherical carbon adsorbents, Kremezin as the brand product and two generics (Merckmezin and spherical carbon adsorbent “Mylan”), were compared. Five non-ionic active pharmaceutical ingredients with molecular weights of 136.1–424.1Da were used as adsorbates. The results of Boehm titration, the standard method to qualify acidic or basic functional groups on a carbon surface, suggested distinctly different quantitative characteristics of each functional group among the three adsorbents. But those differences do not affect the adsorption to non-ionic adsorbates. The amount of theophylline adsorbed at equilibrium and surface area well correlated, suggesting that adsorptive ability was defined by surface area. In the tested molecular weight range, the order in terms of adsorption kinetics was spherical carbon adsorbent “Mylan”>Kremezin>Merkmezin. The adsorption profile in the equilibrium and kinetic experiments, and the lack of an effect of pH on adsorption quantity suggested that the mechanism of adsorption for non-ionic substances to be Langmuir type monolayer adsorption. Kremezin and spherical carbon adsorbent “Mylan” are more likely to adsorb co-administered drugs than Merckmezin.

The numerical analysis of the spherical carbon adsorbents obtained from ion-exchange resins in one-step steam pyrolysis

This paper presents the numerical analysis of spherical carbon adsorbents produced by the single-step steam pyrolysis of a polystyrene-divinylbenzene resin. The porous structure of the materials produced this way was easily controlled by varying such factors as the carbonization temperature, atmosphere or the heating rate, allowing carbonaceous materials to have a controlled microporous structure. Due to their unique properties, the obtained adsorbents can be considered applicable in various processes in technology and environmental protection. The fast multivariant fitting procedure with the new adsorption numerical models of the LBET class was used for the analysis of the microporous structure. The computer calculations using the LBET class models with the fast multivariant identification procedure were carried out with the application of the nitrogen (77.15K) adsorption isotherms.

Comparison of physico-chemical characteristics among three pharmaceutical spherical carbon adsorbents

In this study, various physicochemical characteristics were evaluated for three pharmaceutical spherical carbon adsorbents, Kremezin as a brand product and its generics; Merckmezin and Spherical Carbon Adsorbent “Mylan”. Scanning electron microscopic observations, measurements of specific surface area, particle sizes, and pore volume distributions by mercury intrusion porosimetry, and dynamic vapor sorption (DVS) analysis were conducted. Compared to Kremezin, Merckmezin is dented with a small pore-rich structure; pores of less than 10nm make up 43% (Kremezin) and 68% (Merckmezin) of total pore volume. On the other hand, Spherical Carbon Adsorbent “Mylan” is porous with macropores. The results of fractal dimension analysis of micropores suggested that the complexity of the internal pore structure is Merckmezin>Kremezin≫Spherical Carbon Adsorbent “Mylan”. The three spherical carbon adsorbents are physico-chemically different, but clinical studies should be conducted to prove that they are therapeutically equivalent.

New phosphorus-containing spherical carbon adsorbents as promising materials in drug adsorption and release

A simple method of preparation of new high surface area spherical carbon adsorbents is presented. The phosphoric acid activation upon hydrothermally formed spherules was employed to produce carbons having controlled high specific surface area (over 2100 m 2/g), large volumes of pores (1.2 cm 3/g), and high acidity. Prepared from sucrose materials show high adsorption capacities (i.e. 220 mg/g C) toward paracetamol. It is proved that for these materials the contents of surface phosphorus are responsible for the reversibility of drug adsorption/release process.

One-Step Steam Pyrolysis Preparation and Characterization of Spherical Carbon Adsorbents Obtained from Ion-Exchange Resins

Using the single-set steam pyrolysis of Dowex 50 WX-2 (a polystyrene-divinylbenzene resin), Spherical Carbon Adsorbents (SCAs) were prepared. The porous structure of the materials obtained was easily controlled by varying the heating rate, allowing carbons having a controlled ratio of micropores to mesopores to be obtained. These materials are promising for the adsorption of phenol from aqueous solutions. Moreover, due to the relatively small amount of irreversibility exhibited in such adsorption, they could find potential use in environmental protection.

球形吸着炭製剤の先発医薬品に対する後発医薬品の物理化学的性質と吸着特性の比較

We compared the in vitro performance of brand-name and generic spherical carbon absorbents by studying their physicochemical and adsorptive properties.There was no correlation between specific surface area and adsorption rate for pigment substances.The adsorption removal rates for pigment substances and uremic toxins were almost the same for Kremezin and Kyucal but the adsorption removal rates of some substances were lower for Merckmezin than those for Kremezin.In addition,the adsorption rates for digestive enzymes,important in vivo substances that should not be adsorbed,were high for Kremezin but low for Kyucal and Merckmezin.We found that Kremezin and Kyucal were comparable as regards the adsorption removal rate of indole in the presence of pepsin and sodium cholate,in vivo substances,but with Merckmezin,the adsorption removal rate for indole was lower.In our findings,we noted that the adsorption performance of the generic product Kyucal for most substances was equivalent to that of Kremezin while the adsorption performance of Merckmezin for some substances was lower than that of Kremezin.As a particular conclusion,the lower adsorption removal rate of Merckmezin for indole in the presence of vivo substances needs to be taken into consideration as this will affect clinical results.

On the preparation of synthetic carbon adsorbents using the sulfonated ion exchange resin duolite C-20

Thermal analysis was used to study thermal behavior of the sulfonated ion exchange resin Duolite C20 in the hydrogen, sodium and calcium forms. The aim of this paper was to prepare spherical carbon adsorbents. SEM and AFM microscopic methods have been applied to describe their surface characteristics. It was stated that structural parameters of prepared active carbons depend on the kind of cation present in the resin. The use of calcium form of Duolite C20 as the initial polymer precursor allowed to obtain the active carbon with better yield and better developed pore structure compared with other forms of this ion exchanger.

Preparation, characterization and adsorption application of spherical carbon adsorbents obtained from sulfonated polymers

Investigations of the production and steam activation of synthetic spherical carbon adsorbents from an ion-exchange resin have been carried out. The spherical adsorbents are obtained by carbonization of a polysulfonated cation-exchange resin containing different amounts of the sulfonic group on its surface. As a secondary process, steam activation of the carbons obtained was used, which created the possibility of forming adsorbents with the desired surface area and pore structure. In some activation processes a cation catalyst was used. Heat treatment and/or partial activation in the temperature range 873–1173 K caused burning of 10–70% of the initial weight of the carbon adsorbent, which leads to formation of an active carbon adsorbent with a surface area of 400–1100 m 2 g −1. The adsorbent obtained was used for adsorption of various volatile organic compounds from air or from aqueous solution by the dynamic head space technique, and then the adsorbed compounds were recovered directly by column thermodesorption (on-line) in order to be determined chromatographically. For some of the compounds investigated, the test of sorbent effectiveness in removing chlorinated organic compounds (i.e., trihalomethanes (THM) and chlorophenols) from aqueous solution was performed using solid phase extraction (SPE).