Activated Carbon Particles Research Articles

Alumina membrane coated activated carbon: a novel strategy to enhance the mechanical properties of a solid catalyst

A novel strategy is described to enhance mechanical properties of solid catalyst by coating a thin layer of alumina membrane on activated carbon particles. This method can make the attrition index of activated carbon decrease significantly.

Tribological and mechanical properties of self-lubrication epoxy composites filled with activated carbon particles containing lubricating oil

A self-lubrication composite incorporating activated carbon particles containing lubricating oil (AC-oil) was fabricated in an epoxy resin matrix.

Influence of Activated Carbon Particles on Intermetallic Compound Growth Mechanism in Sn-Cu-Ni Composite Solder

The influence of Activated Carbon (AC) particles on mechanical properties of Sn-Cu-Ni-xAC solder joint was investigated. Five different Activated Carbon (AC) percentage addition (0 wt. %, 0.25 wt. %, 0.5 wt. %, 0.75 wt. %, and 1.0 wt. %) were prepared via powder metallurgy (PM) technique. Interfacial IMC thickness measurement and shear strength results showed that with thinner IMC layer (by increasing amount of wt.% of AC), the higher the shear strength of the joint. It is believed that the AC particles suppresses the interfacial IMC growth and thus improves the shear strength.

Decision-making framework for the application of in-situ activated carbon amendment to sediment

This study provides a decision-support framework and a design methodology for preliminary evaluation of field application of in-situ activated carbon (AC) amendment to sediment to control the (bio)availability of hydrophobic organic contaminants. The decision-making framework comprises four sequential steps: screening assessment, input parameter determination, model prediction, and evaluation for process optimization. The framework allows the application of state-of-the-art experimental and modeling techniques to assess the effectiveness of the treatment under different field conditions and is designed for application as a part of a feasibility study. Through a stepwise process it is possible to assess the effectiveness of in-situ AC amendment with a proper consideration of different site conditions and application scenarios possible in the field. The methodology incorporates the effect of various parameters on performance including: site-specific kinetic coefficients, varied AC dose and particle size, sediment and AC sorption parameters, and pore-water velocity. The modeling framework allows comparison of design alternatives for treatment optimization and estimation of long-term effectiveness over a period of 10–20 years under slow mass transfer in the field.

Treatment of TNT red water by chemical-modified carbon adsorbent prepared from cheap raw materials of pine tree wood

This work reports the treatment of trinitrotoluene (TNT) red water by chemical-modified carbon adsorbent. The pine wood was used for preparation of carbon particles. The chemical modification by solutions of HNO3, ZnCl2, and NaOH was made for activation of carbon adsorbent. The activated carbon particles were characterized by X-ray diffraction (XRD) pattern, FT-IR spectra, scanning electron microscope (SEM) images, BET, and CHNS analyses. The formation of amorphous carbon was confirmed by XRD pattern. The variation of pores of carbon particles before and after the treatment of TNT red water was seen from SEM images. The area and pores volume of activated carbon were obtained 197–211 m2/g and 0.149–0.157 cm3/g, respectively. The considerable decrease of chemical oxygen demand amount was obtained after the treatment of TNT red water samples with activated carbon by HNO3 solution. Treatment experiments were carried out using batch method. The treatment efficiency of 90% was obtained in optimized parameters of pH value of 3, adsorbent dose of 40 g/L, and contact time of 300 min. Adsorption process followed the pseudo-second-order kinetic model. Thermodynamic studies revealed that the adsorption process is spontaneous (−ΔG = 10.4–12.5 kJ/mol) and endothermic (ΔH = 10.7 kJ/mol) at temperature range of 25–55°C. The sorption isotherm was in good agreement with the Freundlich isotherm for TNT red water diluted in range of 100–500 times. Desorption process using sodium hydroxide and boiling water for reuse of the adsorbent were studied and the removal efficiency of 48–72% was obtained in three times of reuse of carbon adsorbent.

Effects of adsorbents on benzo(a)pyrene, sesamol, and sesamolin contents and volatile component profiles in sesame oil

Effects of adsorbent treatments used for reduction of benzo(a)pyrene (BaP) levels in volatile profiles and sesamol and sesamolin antioxidant contents in sesame oil were evaluated. Charcoal-based activated carbons with different mesh sizes and celite were used as adsorbents. Treatment with activated carbons led to reductions in BaP contents of sesame oil. A small charcoal-based activated carbon particle size was more effective for removal of BaP. Celite; however, did not show an effect on the BaP content of sesame oil under the experimental conditions. Volatile profiles of sesame oil were not influenced by addition of any adsorbent, and the sesamol and sesamolin contents were reduced by all adsorbents.

Microstructure of Activated Carbon Particles Coated on High Density Polyethylene (HDPE) for Wastewater Treatment Application

This research aims to study the effect of activated carbon particles in adsorption of the methylene blue as a replacement of wastewater treatment when coated on a high density polyethylene (HDPE) substrate (e.g. flat sheet and cosmo ball substrates). Prior to coating, the activated carbon has been cleaned using tab water to remove ashes which blocks the activated carbon pores. Coating was done by applying epoxy material using brushing technique, and then sprayed the activated carbon on epoxy either manually or using spray machine. The thickness and morphological of the coatings were characterized using Scanning Electron Microscopy (SEM). Analyses conducted have confirmed that granuler activated carbon coating layers ranged between 100 to 500 μm have been successfully deposited on different shapes of HDPE substrates. The coatings deposited on HDPE substrate produced high surface roughness of around 7 μm. The ability of the coated samples in removing the colour of methylene blue is believed due to the high porosity of the activated carbon(AC). The surface area has been increased dramatically if compared with uncoated substrate since the BET of activated carbon is 426 m2/g .

Flux enhancement in membrane distillation by incorporating AC particles into PVDF polymer matrix

In this paper, a novel method of preparing porous hydrophobic membrane was proposed and further experiments had been carried out for verification. A kind of hydrophobic porous inorganic particles, macroporous structure activated carbon (AC), was introduced into polyvinylidene fluoride (PVDF) polymer matrix to fabricate porous membrane for vacuum membrane distillation (VMD) application. The incorporation of AC particles in the polymer matrix can efficiently enhance the membrane permeability because of the intrinsic porous structure of AC particles could directly provide water vapor mass transfer channels in the VMD process. Results showed that: the VMD flux of PVDF hydrophobic membranes was obviously improved by the addition of AC particles. When 0.09wt% AC particles were added in membrane casting dope, a VMD flux of 54.9kg/m2h was obtained. The flux is 30% higher than that of pure PVDF membrane (42.0kg/m2h). Furthermore, the conductivity of the M-3 membrane was kept lower than that of pure PVDF membrane in the 16h continuous desalination experiments. All of the results demonstrated that the prepared PVDF/AC hollow fiber membrane not only has higher permeability but also exhibited satisfying performance stability. It performed well in the VMD program and is expected to be applied in the field of MD to improve the MD membrane performance.

Recycling supercapacitors based on shredding and mild thermal treatment

Supercapacitors are widely used in electric and hybrid vehicles, wind farm and low-power equipment due to their high specific power density and huge number of charge–discharge cycles. Waste supercapacitors should be recycled according to EU directive 2002/96/EC on waste electric and electronic equipment. This paper describes a recycling approach for end-of-life supercapacitors based on shredding and mild thermal treatment.At first, supercapacitors are shredded using a Retsch cutting mill. The shredded mixture is then undergone thermal treatment at 200°C to recycle the organic solvent contained in the activated carbon electrodes. After the thermal treatment, the mixture is roughly separated using a fluidized bed method to remove the aluminium foil particles and paper particles from the activated carbon particles, which is subsequently put into water for a wet shredding into fine particles that can be re-used. The recycled activated carbon has a BET surface area of up to 1200m2/g and the recycled acetonitrile has a high purity.

Low-Cost Dye-Sensitized Solar Cells Based on Interconnected FTO-Activated Carbon Nanoparticulate Counter Electrode Showing High Efficiency

The development of low-cost DSCs (Dye-sensitized solar cells) based on activated carbon counter electrodes is described. Although, the use of activated carbon in CEs (Counter electrodes) has been documented, the efficiencies obtained in such solar cells have been low, particularly, due to low electrical conductivity of such counter electrodes. Our design of the counter electrode eliminates this problem by using an in-situ formed FTO (Fluorine-doped tin oxide)-activated carbon composite on FTO surface as the CE. The FTO particles are prepared by atomized spray pyrolysis method from a spray solution containing dispersed activated carbon particles. The CE thus prepared has a reasonable electronic conductivity and the composition of the spray solution was optimized to give the highest conversion efficiency and the thickness of the CE was optimized by controlling the spray duration and deposition temperature. The best DSC based on AC-FTO CE has a JSC of 18.98 mA·cm -2 , a VOC of 0.709 V, and a FF (Fill factor) of 0.563 giving a conversion efficiency of 7.6%. The data for Pt-FTO CE based DSC are a JSC of 18.78 mA·cm -2 , a VOC of 0.732 V, and a FF of 0.688 with a conversion efficiency of 9.5%.

Optimized preparation of activated carbon nanoparticles from acrylic fibrous wastes

In present study, activated carbon is prepared by controlled pyrolysis of acrylic fibrous waste under the layer of charcoal using physical activation in high temperature furnace. The main objective is to study the effect of four factors (i.e. final pyrolysis temperature, holding time at final temperature, heating rate per hour, and number of steps) on carbonization behavior of acrylic fibrous waste. The Box-Behnken design and response surface modeling was performed to get higher specific surface area and higher electrical conductivity. The development of porous morphology having higher surface area is found to increase with increase in pyrolysis temperature, increase in number of steps, decrease in holding time and decrease in heating rate till some optimum value. This behavior is attributed to gradual reaction of atmospheric oxygen with carbonized acrylic fibrous waste, which resulted into the opening of previously inaccessible pores through the removal of tars and disorganised carbon. Moreover, these four factors also found to have significant effect on the development of electrical conductivity of activated carbon. Later on, the carbonized acrylic fibrous waste was pulverized in dry conditions by high energy planetary ball milling to get activated carbon nanoparticles. In addition to refinement of size, the specific surface area and electrical conductivity of pulverized carbon particles was found to increase with increase in milling time. The activated carbon particles obtained after three hours of dry milling revealed the particle size of 521 nm, the electrical conductivity of 21.78 s/m for 0.5 wt % concentration of aqueous dispersion and the specific surface area of 432 m2/g.

Correlation of energy storage performance of supercapacitor with iso-propanol improved wettability of aqueous electrolyte on activated carbon electrodes of various apparent densities

Addition of iso-propanol in the aqueous electrolyte of 1.0mol/L Na2SO4 was found to be most effective at about 8vol.% to minimise electrolyte surface tension, and hence maximise electrolyte wetting on a commercial supercapacitor grade activated carbon powder. The wetting improvement was further studied on die-pressed cylindrical thin pellets of polytetrafluoroethylene bonded activated carbon powder at three different apparent densities (0.70, 0.55 and 0.35g/cm3) using adsorption isotherm, cyclic voltammetry and electrochemical impedance spectroscopy. Enhanced charge storage performance of the activated carbon at 0.70 and 0.55g/cm3 in apparent density was observed in electrolyte containing iso-propanol. The effect of iso-propanol became more prominent at high polarisation potentials. However, at the lowest density (0.35g/cm3) studied, the capacitance decreased in the presence of iso-propanol, which can be attributed to the iso-propanol molecules entering the nano-pores of the activated carbon particles. In symmetrical supercapacitors with the dense activated carbon electrodes, addition of iso-propanol to the aqueous electrolyte increased the cell voltage, specific energy and maximum specific power from 1.5 to 2.0V, 7.34 to 12.44Wh/kg, and 3.96 to 12.35kW/kg, respectively, under comparable conditions.

Adsorption capacities of activated carbons for geosmin and 2-methylisoborneol vary with activated carbon particle size: Effects of adsorbent and adsorbate characteristics

The adsorption capacities of nine activated carbons for geosmin and 2-methylisoborneol (MIB) were evaluated. For some carbons, adsorption capacity substantially increased when carbon particle diameter was decreased from a few tens of micrometers to a few micrometers, whereas for other carbons, the increase of adsorption capacity was small for MIB and moderate for geosmin. An increase of adsorption capacity was observed for other hydrophobic adsorbates besides geosmin and MIB, but not for hydrophilic adsorbates. The parameter values of a shell adsorption model describing the increase of adsorption capacity were negatively correlated with the oxygen content of the carbon among other characteristics. Low oxygen content indicated low hydrophilicity. The increase of adsorption capacity was related to the hydrophobic properties of both adsorbates and activated carbons. For adsorptive removal of hydrophobic micropollutants such as geosmin, it is therefore recommended that less-hydrophilic activated carbons, such as coconut-shell-based carbons, be microground to a particle diameter of a few micrometers to enhance their equilibrium adsorption capacity. In contrast, adsorption by hydrophilic carbons or adsorption of hydrophilic adsorbates occur in the inner pores, and therefore adsorption capacity is unchanged by particle size reduction.

Adsorption of creatinine on polyaniline-poly(styrene sulfonate) hydrogels based activated carbon particles

Polyaniline-poly(styrene sulfonate) (PAn-PSS) hydrogels-based powdered activated carbons (PAC) were prepared and investigated. Structural properties of PAC were characterized by nitrogen absorption–desorption and elemental analysis. Surface properties of PAC were studied by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. Activated carbon particles possessed high mesopore ratio of 54 % which can ensure the smooth entrance of the adsorbates of proper size. On the other hand, these materials were nitrogen-enriched due to the PAn-PSS precursor. Amino groups are tended to form chemical bonds with certain adsorbates which help intensify the interaction between PAC and certain adsorbates, thus promote their adsorption on PAC. The adsorption behavior of creatinine on these activated carbon particles was also studied. In comparison with the coconut shell activated carbon particles, PAC showed a better (P < 0.05, statistically) adsorption ability of 341.2 mg/g. Freundlich model was employed to describe the isothermal adsorption behavior of creatinine on PAC and the coefficient of determination (R 2) was greater than 0.98. Moreover, the study of the adsorption kinetics showed that the equilibrium condition of creatinine adsorption on PAC can be reached within 7 h and the adsorption ratio was 53.7 %. Kinetic adsorption data were well fitted according to the pseudo-second-order model, implying that it was a chemisorption process and the adsorption mechanism involved intermolecular H-bonding between adsorbent and adsorbate.

Activated Carbons from Gambeya Albida and Telfairia Occidentalis Seed Shells: Effect of Activating Agent on the Removal of Pb(II) Ions from Aqueous Solutions

Activated carbons were produced from Gambeya albida and Telfairia occidentalis seed shells by chemical activation and their properties were determined. The effects of different production conditions (activating agent, carbonization temperature and carbonization time) were studied and it was found that activation with H3PO4 gave carbons with better properties than activation with NH4Cl. Also, bulk density and % yield of the adsorbents decreased while surface area, total pore volume, % weight loss and % ash content increased with increase in carbonization temperature from 300 to 600 o C and carbonization time from 60 to 180 minutes for both raw materials. The potential of removal of Pb(II) ions from aqueous solution by selected activated carbon from both raw materials was also studied and it was found that the adsorption capacity was influenced by the contact time, initial Pb(II) concentration, solution pH, activated carbon particle size and dose as well adsorption temperature.

Prussian blue/graphene-modified electrode used as a novel oxygen reduction cathode in microbial fuel cell

Prussian blue/graphene (PB/GE) nanocomposite was successfully synthesized and the oxygen reduction reaction (ORR) activities were studied in our previous work. In this study the PB/GE nanocomposite and PB were deposited on the surface of active carbon particles, and the resulted particles were placed in two microbial fuel cells (MFC) as the three-dimensional cathode electrodes for oxygen reduction. The two MFCs were labeled as PB/GE-MFC and PB-MFC, and their performances were evaluated in the long term operation. A series of characterization methods showed the successful deposition of PB/GE and PB on the particles. After the long term operation, the cell voltage and maximum power density of PB-MFC decreased sharply, which dropped from 530 mV and 15.63 W/m−3 to 395 mV and 7.5 W/m−3, while those of PB/GE-MFC were decreased slightly, which dropped from 530 mV and 16.26 W/m−3 to 470 mV and 15.88 W/m−3. The Tafel constants showed that PB/GE-MFC cathode had higher kinetic activity and faster reactions than PB-MFC cathode. PB/GE had stable performance in the MFC during the long term operation, and it can be used as a novel cathode as an effective alternative to platinum for oxygen reduction in MFC.

Electrically conductive PVC layers filled with active carbon containing H+-conducting porous structures of sulfuric acid complexes of cyclams on fabrics

Electrically conductive PVC layers are synthesized. The layers are filled with active carbons containing porous H+-conductive structures of hydroxyethylcyclam/sulfuric acid complexes crosslinked with cellulose fabric. They are interlaid with layers based on the same structures containing added benzene and hexane adsorbates and solvates. It is found that upon anode or cathode polarization of the layers as H+-conductive electrochemical bridges in air and in the vapor and liquid phases of benzene and hexane, either the electroreduction of H+ to H2 or the electrooxidation of H2O to O2 occurs in the areas of contact between active carbon particles and the complexes. The dependences of rates of H2 and O2 formation on the voltage are studied. The magnitudes of overvoltage and the constants of electrochemical reactions are found to depend on the composition of a layer.

Effects of Activated Carbon Particle Sizes on Caffeine Adsorptions

【The effect of activated carbon particle diameter (i.e. US sieve No. $8{\times}10$ ( $d_p{\approx}2.19mm$ ), $18{\times}20$ ( $d_p{\approx}0.92mm$ ), $50{\times}60$ ( $d_p{\approx}0.27mm$ ) and $170{\times}200$ ( $d_p{\approx}0.081mm$ ) on caffeine adsorption is investigated. BET surface area was increased with decreasing particle diameter ( $d_p$ ), and caffeine adsorption rates increased with decreasing $d_p$ . Moreover, pseudo-second order model is predicted the experimental data more accurately than pseudo-first order model, and the fastest rate constant ( $k_2$ ) was $1.7g\;mg^{-1}min^{-1}$ when $d_p$ was 0.081 mm. Surface diffusion coefficient (Ds) was decreased with decreasing $d_p$ based on the minimum sum of square error (SSE). Practically, certain ranges of Ds are acceptable with high reliability ( $R^2$ ) and it is determined that the effect of $d_p$ on Ds is unclear. The effect of pH on caffeine adsorption indicated the dependency of m/L ratio (mass liquid ratio) and $pH_{pzc}$ . The $pH_{pzc}$ (i.e. $7.9{\pm}0.2$ ) was not affected by $d_p$ . The higher caffeine adsorption at pH 4 and pH 7 than at pH 10 is due to $pH_{pzc}$ , not $pk_a$ of caffeine.】

Fabrication of conductive carbonaceous spherical architecture from pitch by spray drying

Continuous spray drying used to synthesize amphiphilic sulfonated pitch-based spherical nanoparticles was reported in this study. The spherical particles were further carbonized and activated by KOH to obtain porous spheres. N2 adsorption–desorption, mercury porosimetry and Raman spectroscopy were used to investigate the pore structure and electron conductivity of the resulting spherical activated carbon particles. The results show that the porous spheres had a high specific surface area (e.g., up to 2550m2g−1) and a continuous pore size distribution that varied from micropores to macropores. This interconnected 3-D carbonaceous architecture efficiently improved the electrical conductivity and facilitated a better utilization of the inner-pores for energy storage. These two aspects combine together to guarantee a low internal resistance and a good rate performance to an EDLC using these spherical nanoporous carbons as the electrodes. In 1M TEA-BF4/PC solution, such EDLC showed a specific capacitance of 173Fg−1 at 0.05Ag−1 and 115Fg−1 at 10Ag−1. Its energy density gets to 43.8Whkg−1 and maintains at 24.16Whkg−1 even the power density rises up to 25kWkg−1.

Preparation of nano-silver-supported activated carbon using different ligands

In this study, we investigated the effect of water soluble ligands [i.e., sodium borohydride (NaBH4), polyvinyl alcohol, glucose and galactose] on the preparation of nano-silver-supported activated carbon (AC). Ligand-stabilized Ag nanoparticle dispersion characteristics were also compared with those of ligand-free Ag nanoparticles. The nanoparticle distribution was investigated using a scanning electron microscope (SEM) which enabled a qualitative analysis of ligand-dependent nanoparticle adsorption onto AC. Silver nanoparticles with average sizes ranging from 7 to 20 nm were synthesized with different coatings. In particular, silver nanoparticles reduced and stabilized by NaBH4 were found to have a dense and homogenous dispersion of sizes in the range of 100–400 nm on the AC surface. These particles also seemed to remain on the AC surface after rinsing with water. The distribution of silver nanoparticles prepared in the presence of NaBH4/PVA was not as good as the one prepared with NaBH4. Their aggregate size varied from 300 to 600 nm on the AC surface and particles greater than 500 nm were eliminated from the AC surface upon rinsing with water. Glucose- and galactose-stabilized silver nanoparticles did not display an extensive adsorption and their adsorption seemed to be poor. However, glucose-stabilized silver nanoparticles could still be detectable to some extent after rinsing, while galactose-stabilized ones could not. Antimicrobial studies showed that all silver-containing carbons studied in this study inhibit bacterial growth and act as bacteriostatic agents.