Adsorption Capacity Of Activated Carbon Research Articles

Effects of calcium ion and pH on the adsorption/regeneration process by activated carbon permeable reactive barriers.

Activated carbon (AC) is widely used in groundwater remediation, more specifically, for the activated carbon permeable barriers (AC-PRBs). However, the long-term use of AC-PRBs is limited by the AC's adsorption capacity. In this work, a Fenton-combined persulfate system (Fe2+/H2O2/S2O82−) was used to treat activated carbon that was saturated with organic compounds, such as trichloroethylene (TCE), to promote the oxidation of the adsorbed contaminants and the regeneration of AC. The effect of pH and the calcium ion (Ca2+) were investigated during AC's adsorption/regeneration. The results showed that under certain reaction conditions (TCE/Fe2+/H2O2/S2O82− molar ratio of 1.00/9.00/56.63/76.25), acidic pH conditions (pH = 3) favored the adsorption/regeneration process of AC, yielding a regeneration efficiency of 26.28% on average in three regeneration cycles. The presence of Ca2+, even in relatively low concentrations, seemed to decrease HO˙ generation and AC's adsorption capacity.

Treatment of mature landfill leachate using hybrid processes of hydrogen peroxide and adsorption in an activated carbon fixed bed column

ABSTRACTIn this study, the treatment of mature landfill leachate is evaluated by oxidation with hydrogen peroxide (H2O2) combined with adsorption in a granular activated carbon (GAC) fixed bed column to determinate the increase in the biodegradability index, the reduction of chemical oxygen demand (COD) as well as the increase in the useful life of the GAC bed. The sample leachate from Loma de Los Cocos Landfill (Cartagena de Indias, Colombia) has a very low biodegradability ratio ranging from 0.034 to 0.048 that makes it difficult to meet the required water quality level according to the regulations. The COD removal is initially monitored in the H2O2 oxidation treatment process. The operating conditions such as pH, H2O2 dosage, and the reaction time are optimized in this process based on the percentage of COD removal. A maximum COD removal of 29.9% is achieved at an initial H2O2 concentration of 5000 mg L−1 with a pH of 8 and the reaction time of 60 min. The hybrid treatment by H2O2-GAC achieved 97.3% COD removal and 116% increase in the biodegradability ratio (from 0.072 to 0.134) while this ratio was increased by 6.5% with H2O2 alone. Moreover, the useful life of the GAC bed is increased from 45 min in the column fed with raw leachate to 170 min in the column fed with pretreated leachate and 5000 mg L−1 of H2O2 at pH of 8 that subsequently increased the activated carbon adsorption capacity. An adsorption model for leachate treated with H2O2 is also developed.

Isobutanol Vapor Adsorption on Activated Carbons: Equilibrium and Kinetic Studies

Activated carbon (AC) is commonly used to remove volatile organic compounds (VOCs) from the air. The purification efficiency depends on adsorbent characteristics (surface area, pore size, surface chemistry), adsorbate properties (size, functional groups, polarity), and process conditions. In the present study, the affinity of the Sorbonorit 4 (S4), Sorbonorit B4 (SB4), and BPL 4 × 6 (BPL) activated carbons toward the isobutanol (i-BuOH) vapor adsorption was investigated. The impact of vapor pressure and temperature on the process efficiency was examined. Adsorption equilibrium and kinetic measurements were conducted at 293.15, 313.15, 348.15, 373.15, and 393.15 K using an intelligent gravimetric analyzer (IGA). Experimental isotherm data were analyzed using the multitemperature Toth, Sips, and hybrid Langmuir–Sips models. Results indicated that the Sips model gave somewhat better fit than the others. The adsorption capacities of ACs at the same vapor pressure followed the order: S4 > BPL > SB4. Adsorption...

Activated Carbon from Date Seeds for CO2 Capture Applications

Considerations for reducing global carbon emissions are influencing the development of solid sorbents such as activated carbons for carbon dioxide (CO2) capture. Adsorption efficiency often relies on method of preparation and starting or source materials. The use of agricultural wastes such as date seeds are regarded as cost- effective options to produce activated carbons for carbon capture. However, there has been no published study on the potentials of date seeds synthesized activated carbon for carbon capture. In preparing activated carbon (AC) from date seeds by physical activation technique, this study reports on the effects of pyrolysis temperature and activation time on the yield and adsorption capacities of AC produced. Optimal temperature for pyrolysis was 800°C, while activation temperature which had the highest CO2 adsorption capacity was 900°C with a loading of 141.14 mg adsorbed CO2/g activated carbon. Sample characteristics such as surface area and porosity, infrared spectra, and scanning electron microscopic images were also investigated in this study.

ADSORPSI KARBON AKTIF DARI TONGKOL JAGUNG SEBAGAI ADSORBEN ION LOGAM Cu2+

Many reseerches about agricultural waste shows potency from this waste to be used as high quality of active carbon that can be used as (adsorbent) on gasoline and substances dissolved at solution. One of agricultural result in South Sumatera that is enough corn cob, where is solid waste that throun just. It is impossible since corncob contains about 40 % of cellulose. So, cellulose which can be used as an active carbon. There are two basic processes in the active carbon making, those are carbonization and activation. The aim of this study was to find out how the activated time gave influence to the adsorption capacity of active carbon as the metal ion Cu2+ adsorbent. The obtained data were analysed by using Atomic Adsorption Spectrophotometry (SNI 06-6989.6-2009). Moreover, the characteristic of the active carbon was ansalysed by Standart Nacional Indutrial (SNI 06-3730-1995). From the result of study, it was obtained that the activated time of 60 minutes with the activator H3PO4 0,5 M had the best adsorption capacity of 1.97 mg/g with the metal ion Cu2­+ concentration was 0,80 ppm. The characteristic of the missing part 9500C 20.54 %, water content of 11 %, ash content of 7 % and iodine number of 750.35 mg/g, pure active carbon 72.46 %, the density of bulk 0.31 g/ml, pass for the mesh size of 325 is 98 %. The adsorption capacity of active carbon from the corncob to the metal ion Cu2+ taken from the waste water sample at the shipyard painting work shop in Palembang was 0.1644 mg/g (97.60 %).
 Key words : Activated Carbon, Corn cob, Adsorption, AAS, Copper (II) Metal Ion.

Synthesis of MnO2 on Activated Carbon and its Potential Application in the Adsorption of As(V) and Pb(II) in Aqueous Solutions.

The conditions for the synthesis of a material with MnO2 (OMD) on activated carbon (AC) were studied. These conditions were: reaction time, temperature, stirring speed, concentrations of AC, H2SO4, and O3 in solution, and particle size. Agglomerates on AC were observed by means of scanning electron microscopy (SEM) and microanalysis by energy dispersive spectroscopy (EDS) and revealed the presence of OMD deposited on the surface. The activation energy and the factor of frequency for the reaction were determined as Ea = 1.2 kcal/mol and A = 2.2. The value of Ea indicates that the precipitation of OMD on the AC was controlled by mass transfer in aqueous solution and the order of reaction was zero. The adsorption capacities of AC were q = 14 mg Pb(II)/g AC and q = 9.1 mg As(V)/g AC. Whereas, for the OMD/AC obtained in the following conditions: [AC] 1 or 2 g/L, particle size of AC of +0.59 mm, [H2SO4] 1 or 2 mol/L, 25 °C, stirring speed 600 rpm, and [O3] 1.35 mol/L, the adsorption capacities were q = 90.5 mg Pb(II)/g OMD/AC and 25.4 mg As(V)/g OMD/AC. Therefore, the fixing of OMD on the surface of the AC greatly improved the removal of both Pb(II) and As(V) from aqueous solutions.

Evaluation of adsorption efficiency of activated carbon/chitosan composite for removal of Cr (VI) and Cd (II) from single and bi-solute dilute solution

The aim of this study was to evaluate the adsorption capacity of the novel coated activated carbon by chitosan for removal of Cr (VI) and Cd (II) ions from single and bi-solute dilute aqueous solutions. In addition, the adsorption abilities of activated carbon (AC), chitosan (CH) and chitosan / activated carbon composite (CHAC) have been compared. Adsorption studies were performed in a batch system, and the effects of various operating parameters such as solution pH, particle size and the dose of adsorbent were considered for removal of Cr (VI) and Cd (II) by Taguchi method. Equilibrium experimental data were well fitted to Langmuir isotherm for single and bi-solute solutions. The adsorption capacities of AC and CH adsorbents have improved by synthesis CHAC composite. As it was expected, competitive adsorption of metal ions on the CHAC surface led to reducing the adsorption capacity from 90.9 mg g-1 to 41.94 mg g-1 for Cr (VI) and 52.63 mg g-1 to 30.21 mg g-1 for Cd (II) ions, respectively. The adsorption capacities for the metal solution–adsorbent systems are in the order Cr (VI) > Cd (II). The kinetic studies indicated that the adsorption process was best described by the pseudo-second-order kinetics for single and bi-solute solutions.

ADSORPSI ZAT WARNA METILEN BIRU DENGAN KARBON AKTIF DARI KULIT DURIAN MENGGUNAKAN KOH DAN NaOH SEBAGAI AKTIVATOR


 Durian is a kind of tropical fruits which can grow well in Indonesia. Durian is containing 60-75% shell. Durian shell could be a potential alternative to activated carbon because it contains 57.42% carbon. The aim of this research is to know the effect of contact time and stirring speed to activated carbon adsorption capacity from durian shell with KOH and NaOH as activators. FTIR (Fourier Transform Infra Red) analysis showed the activation process effects on absorption intensity wavelength region and resulted in formation of C = C aromatic tape, so that the nature of the charcoal becomes more polar compared with the initial condition. Analysis using spectrophotometer UV-Vis to determine absorbance and final concentration of each variation of contact time and stirring speed. The results showed that the maximum adsorption capacity obtained by activation of KOH and NaOH on stirring speed of 150 rpm and a contact time of 90 minutes is equal to 3.92 mg / g and 3.8 mg / g respectively. The maximum surface area obtained by activation of KOH and NaOH during the stirring speed 130 rpm and a contact time of 120 minutes is equal to 1785.263 m2 / g and 1730.332 m2 / g respectively. The maximum surface area obtained from this research has met the standards of commercial activated carbon surface area was between 800-1800 m2/ g. Modeling pseudo second order presents a more representative adsorption data, a second order equation is based on the assumption that adsorption step is chemosorption.

CO<sub>2</sub> Adsorption on Activated Carbon/SBA-15 with TETA/TEPA Modification

Activated carbon (AC), the KOH-modified activated carbon (KAC) and mesoporous material SBA-15 before and after pore expansion (SBA-15k) were modified using triethylenetetramine (TETA) and tetraethylenepentamine (TEPA) as modifiers. The CO2 adsorption capacities of adsorbents were determined by thermogravimetric method. The results show that at 60 °C and the atmosphere of 15% CO2 (volume fraction), with the increasing of amine loading amount, the CO2 adsorption capacities of AC and KAC decreased gradually. While those of SBA-15 and SBA-15k increase at first stage and decrease subsequently. Cyclic CO2 adsorption capacities and mass of the adsorbents show no obvious changes, so the adsorbents have excellent stability.

Remoción de clorofilas presentes en extractos de Stevia (Stevia rebaudiana Bertoni) por adsorción con carbón activado y precipitación con cal grado alimenticio

En el presente estudio se evaluó la capacidad de adsorción del carbón activado y el efecto del hidróxido de calcio grado alimentico (cal grado alimenticio) para la remoción de color presente en los extracto de Stevia. Se preparó un extracto para la cuantificación de clorofila A, B y C por el método espectrofotométrico de Hansmann. Posteriormente se midió la capacidad de adsorción del carbón activado y de remoción de la cal sobre la clorofila A, B y C. Los procesos con carbón activado mostraron que con 0.05 g en 100 ml en un tiempo de residencia de 10 min se adsorbió el 43.30% de clorofilas. El proceso de adsorción sobre carbón activado se ajustó al modelo de Langmuir, con una capacidad máxima de adsorción de clorofilas en monocapas de qmax = 962 mgg–1 y un valor de la constante de Langmuir de b = 159.413 gml–1. Para la precipitación con cal se usaron 10 g por cada 100 ml en un tiempo de residencia de 10 min, retirándose el 70.30% de clorofilas.

Experimental Study on Microwave Modified AC and Its Adsorption on Formaldehyde

Formaldehyde is one kind of the main pollutants in indoor air. Formaldehyde is toxic. High concentration formaldehyde can do harm to human seriously. In recent years, the removal of formaldehyde become into the hot point. Activated carbon (AC) adsorption technology is an effective, convenient cheap and easy way to treat indoor formaldehyde gas.AC was prepared by microwave heat treatment and modified. The surface structure and property of the modified AC were studied by BET model and Boehm titration. The adsorptions of formaldehyde on AC have been studied, and the effect of carbonization temperature on adsorptive properties are studied in the paper. The main experimental results show that the adsorption capacity of modified AC is better than that of unmodified AC. When the activation temperature is 800 ℃, the adsorption capacity of AC is the highest, reaching 8.63mg / g, which is higher than that of unmodified AC. The samples were made by the TPD experiment, the modified AC peak area has increased.Through microwave heat-treatment, acidic groups were decomposed to increase alkalinity and content of surface oxygen was reduced, which are the principal reasons for improving adsorption properties.

Concanavalin A Coated Activated Carbon for High Performance Enzymatic Catalysis

A facile method of immobilizing enzymes on activated carbon (AC) is proposed, in which the first step is to coat AC with Concanavalin A (ConA), followed by the adsorption of enzymes. Two model glycoenzymes, horseradish peroxidase and laccase, were immobilized on the ConA adsorbed AC through the tightly specific recognition of ConA to their glycosidic moieties, as confirmed by laser confocal microscopy. The coating layer of ConA reduced the deactivation of enzymes and prevented the leakage of enzymes, as indicated by the significantly improved yield of enzymatic activity. The immobilized enzymes on ConA coated AC appeared an improved stability against pH and temperature, offering an expanded operation “window” for growing applications of the enzymatic catalysis. Finally, the integration of the adsorption capacity of AC and the chemical degradation of laccase promises the efficient removal of aqueous phenol. The improved recovery of enzyme activity, enhanced stability as well as the combination of substrate...

Removal of mixture of ZnO and CuO nanoparticles (NPs) from water using activated carbon in batch kinetic studies.

The aim of this study was to understand the effects of pH (5, 6, 7, 8, 9) and activated carbon (AC) concentration (0.01, 0.1, 1, 10, 100 g/L) on the removal of a colloidal solution of nanoparticles (NPs) (ZnO + CuO) using AC in batch kinetic studies. Results revealed that adsorption capacities of AC for Zn and Cu (individually) were 0.9 ± 0.028 mg/g (91.3% removal) and 0.95 ± 0.036 mg/g (95.6% removal) in deionized water and 0.6 ± 0.038 mg/g (78% removal) and 0.75 ± 0.078 mg/g (83% removal) in wastewater at pH 8 (Zn) and pH 6 (Cu) respectively. In a colloidal solution mixture of zinc oxide nanoparticles (ZnONPs) and copper oxide nanoparticles (CuONPs), adsorption capacity of AC for Zn in deionized water was 0.71 ± 0.051 mg/g (74.7% removal) and in wastewater was 0.576 ± 0.019 mg/g (69% removal) and for Cu in deionized water was 0.82 ± 0.017 mg/g (81.2% removal) and in wastewater was 0.6 ± 0.032 mg/g (71.5% removal). Overall, this study provided a detailed analysis of the removal capacity of AC and indicated that AC can be used as an efficient adsorbent filter for removing engineered NPs like ZnONPs and CuONPs (single and mixture) from water. As there is a need for removing NPs from wastewater, removal of NPs using an AC-based adsorptive-filter might become a promising method.

The application of homemade Neosinocalamus affinis AC in electrokinetic removal technology on heavy metal removal from the MSWI fly ash.

This present paper was focused on the manufacture of activated carbon (AC) and its application in the electrokinetic remediation (EKR) technology on removal of the heavy metals (HMs) from the municipal solid waste incineration fly ash. AC was produced from Neosinocalamus affinis (NF) by chemical activation with H3PO4 in N2 atmosphere, the effects of activation temperatures, soaking time and impregnation ratios on the adsorption capacity of AC on HMs were examined through equilibrium adsorption experiments. The AC produced under the condition of 450 °C of activation temperature, 10 h of soaking time and 1.5 of impregnation ration was applied in the EKR experiment. The addition of AC in the S3-region of the electrolyzer could effectively improve the removal efficiencies of HMs. The technical parameters of voltage gradient, processing time and proportion were further optimized in the coupled experiments, the maximum removal of Cu, Zn, Cd, and Pb was 84.93%, 69.61%, 79.57%, and 78.55% respectively obtained under the optimal operating conditions of 2 V/cm of voltage gradient, 8 d of processing time and 20% of proportion.

Regeneration of sulfamethoxazole-saturated activated carbon using gamma irradiation

Activated carbon (AC) has been widely used for reclamation and reuse of the effluent of wastewater treatment plant to further remove the emerging contaminants, such as PPCPs in recent years. How to regenerate the exhausted AC effectively and economically is still a challenge. In the present study, the regeneration of AC exhausted with SMX was performed by gamma irradiation to simultaneously recover the spent AC and degrade the pollutants. The results showed that the adsorption of SMX onto AC can be described by the Langmuir isotherm and the adsorption capacity was about 417mg/g. SMX can be removed rapidly when exposed to gamma irradiation, with the initial concentration of 100mg/L, more than 99% of SMX was removed at 5.0 kGy, while an extremely high dose (150 kGy) was needed to reach 80% mineralization ratio. The regeneration efficiency was about 21–30% at 50–200 kGy. The absorbed SMX and the intermediates formed during gamma irradiation were released into aqueous solution from AC and mineralized, leading to the partial regeneration of the adsorption capacity of AC. Further studies are needed to optimize the experimental conditions to increase the regeneration efficiency.

Pb(II) adsorption by a novel activated carbon ⿿ alginate composite material. A kinetic and equilibrium study

The adsorption capacity of an activated carbon ⿿ calcium alginate composite material (ACAA-Ca) has been tested with the aim of developing a new and more efficient adsorbent material to remove Pb(II) ion from aqueous solution. The study was carried out at pH=5, in NaCl medium and in the ionic strength range 0.1⿿0.75molL⿿1. Differential Pulse Anodic Stripping Voltammetry (DP-ASV) technique was used to check the amount of Pb(II) ion removed during kinetic and equilibrium experiments. Different kinetic (pseudo first order, pseudo second order and Vermuelen) and equilibrium (Langmuir and Freundlich) models were used to fit experimental data, and were statistically compared.Calcium alginate (AA-Ca) improves the adsorption capacity (qm) of active carbon (AC) in the ACAA-Ca adsorbent material (e.g., qm=15.7 and 10.5mgg⿿1 at I=0.25molL⿿1, for ACAA-Ca and AC, respectively).SEM-EDX and thermogravimetric (TGA) measurements were carried out in order to characterize the composite material. The results of the speciation study on the Pb(II) solution and of the characterization of the ACAA-Ca and of the pristine AA-Ca and AC were evaluated in order to explain the specific contribution of AC and AA-Ca to the adsorption of the metal ion.

Systematic evaluation of the adsorption of organic vapors onto a miniaturized cartridge device using breakthrough tests in parallel experiment with a full size respirator cartridge

Breakthrough experiments are essential for the characterization of the adsorption capacity and micropore volume of activated carbon respiratory cartridges and for the validation and determination of cartridge service life models. In an effort to gain better control over environmental conditions in breakthrough tests and to obtain reliable data, a novel experimental approach using a miniaturized (Mini) cartridge was designed to replicate a small section of a respiratory cartridge. The Mini device and the organic vapor respiratory cartridge were tested in single and parallel experiments where in the former, one filter was tested one at a time and in the latter both devices were exposed simultaneously to the same conditions. The Mini device gave comparable results to the 10% breakthrough times and adsorption capacities of the organic vapor cartridges. The reproducibility of the packed carbon bed of the Mini provided strong support for using the Mini in breakthrough experiments for the characterization of the activated carbon adsorption capacity and estimation of cartridge service life.

Adsorption of thiophene, dibenzothiophene, and 4,6-dimethyl dibenzothiophene on activated carbons

Four activated carbons (ACs) activated by different activation methods from different precursors were heat-treated at 600℃ to decrease surface oxygen functional groups and to separate the effect of pore texture from surface chemistry on their sulfur adsorption performance. The ACs and the heat-treated ones were used as adsorbents for thiophene (T), dibenzothiophene (DBT), and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) for model fuels with or without a competing benzene. The correlations of surface functional groups and pore textures to their adsorption capacities for T, DBT and 4,6-DMDBT were investigated. Results indicated that the heat treatment not only decreased surface oxygen content, but also caused a pore texture modification. The adsorption isotherms can be well fitted by the Langmuir–Freundlich single solute isotherm. The sulfur adsorption capacity of ACs after the treatment for T, DBT, and 4,6-DMDBT has a good linear relationship with the pore volume of pores within 0.536–1.090, 0.536–1.179, and 0.679–1.268 nm, respectively. The decreased percentage of surface oxygen of ACs by the heat treatment is correlated linearly with the decreased percentage of the sulfur adsorption capacity for all the thiophenic compounds. Micropore filling via the π–π interaction is the dominant adsorption mechanism of thiophenic compounds for both the untreated and heat-treated ACs. Surface oxides contribute to the thiophenic adsorption by a cooperative interaction of the π–π interaction and the acid–base interaction between the basic sulfur atom and the acidic carbon atoms linked with oxygen in graphene edges. A flat adsorption is the most possible geometry in the adsorption of thiophenic compounds.

Low temperature destruction of PCDD/Fs by catalysis coupled with activated carbon.

In order to enhance the oxidation and adsorption capacity of catalyst, two kinds of activated carbon (AC) are mechanically mixed with V2O5-WO3/TiO2 catalyst respectively. In this study, the mixtures (M-1: catalyst mixing with AC based on lignite; M-2: the one on coconut shell) are investigated to destroy high concentration (9.8 ng I-TEQ Nm(-3)) PCDD/Fs at low temperature (160 °C). Adding AC into the catalyst obviously increases removal efficiency (RE) and destruction efficiency (DE). However, M-2 presents higher RE value and lower DE value compared with M-1 at the same conditions as the stronger adsorption capacity of AC based on coconut shell. For the M-2 mixture, RE values are decreasing while DE values show an opposite trend with the ratios of catalyst to AC increasing. Oxygen plays a positive role on the destruction of PCDD/Fs by accelerating the conversion of V(4+)Ox and V(5+)Ox. Adjusting oxygen content from 0 to 20 % could increase the DE value from 27.4 to 82.2 % for the M-1 and from 15.8 to 68.9 % for the M-2. In the presence of ozone, a dark brown flock will be generated when the ratio of AC and catalyst is 4:1 due to the reaction between AC and ozone, which results in the lower RE and DE values. The RE and DE values reach the maximum of 96.3 %, 90.6 % in this paper, respectively, when the ratio of AC and catalyst is 1:1 with ozone. Finally, the regenerating of mixture is investigated. Most of dioxin residues in the mixture are desorbed and oxidized by catalysis at 200 °C in the presence of oxygen.

New dextran coated activated carbons for medical use

Activated carbon (AC) can be used for blood purification (hemoperfusion) to treat a range of conditions by direct perfusion of blood through an adsorbent column. The clinical effects of hemoperfusion relate to the AC adsorptive capacity, and any inflammatory response generated by direct blood contact. The use of a biocompatible coating minimizes side-effects but at the same time significantly reduces AC adsorption capacity in particular towards substances with large molecular mass. We investigated the adsorption capacity for biological molecules in a wide range of molecular masses and biocompatibility of a dextran (Dx) coated mesoporous AC (HSGD) produced from a polymer precursor. The hemocompatibility of the Dx-coated beads was investigated according to the ISO guidelines. Coating the HSGD with a Dx coating (5–30% weight of AC) decreased the specific surface area and pore volume of the materials and reduced adsorption capacity for methylene blue, vitamin B12, bilirubin and albumin, while minimizing fines production. Even the partially coated materials did not activate the inflammatory response and thus could be considered hemocompatible, with the Dx coating reducing fibrinogen adsorption and complement generation, suggesting the material warrants continued development for hemoperfusion applications.