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Enhancement of the electrochemical properties of commercial coconut shell-based activated carbon by H 2 O dielectric barrier discharge plasma

sakurajun — Wed, 02 Dec 2020 08:20:29 GMT

Commercial coconut shell-based activated carbon (CSAC)coconut granular carbon has low specific capacitance and specific capacitance retention owing to its undeveloped pore structure and low proportion of heteroatoms. In this study, dielectric barrier discharge plasma was used to enhance the specific capacitance and rate capability of CSAC. H2O was used as an excited medium to introduce oxygen functional groups. The physico-chemical properties of CSAC and CSAC modified by H2O plasma (HCSAC) were revealed by automated surface area and pore size analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Electrochemical work was applied to investigate the electrochemical properties of CSAC and HCSAC. The results obtained showed that plasma modification improved the specific capacitance of CSAC by 64.8% (current density, 1 A g-1; electrolyte, 6 M KOH solution) within 100 s. This result is ascribed to the oxygen functional groups introduced to the surface of CSAC. It can also improve the hydrophilicity and wettability of the carbon surface leading to an increase from 76.7% to 84.6% in specific capacitance retention. Furthermore, H2O plasma modification can introduce oxygen functional groups without destroying the initial pore structures of CSAC. In summary, we provide a simple, fast, environment-friendly modification method to enhance the electrochemical properties of CSAC.activated carbon suppliers

Study on carbon nanotubes and activated carbon hybrids by pyrolysis of coal

sakurajun — Wed, 02 Dec 2020 08:19:42 GMT

Carbon nanotubes (CNTs)coal activated carbon and activated carbon (AC) hybrids were obtained by co-pyrolysis of potassium hydroxide and bituminous coal. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Raman spectroscopy, X-ray Diffraction (XRD), and nitrogen adsorption measurements were used to investigate the characteristics of the samples and the effects of the final pyrolysis temperature and time on the structure of the carbon materials. The results indicated that the optimal range for the pyrolysis temperature and time for CNT growth were 900–950 °C and 45–90 min, respectively. The diameters of the as-prepared CNTs were in the range of 50–250 nm and their lengths were ∼15 μm. During the pyrolysis process, potassium hydroxide not only acted as the catalytic precursor to catalyze the CNT growth but also reacted with carbon to produce abundant micropores. Furthermore, the content of CNTs in the product after demineralization was significantly reduced. It was further confirmed by Inductively Coupled Plasma (ICP) analysis that the content of Fe, Co, and Ni decreased after demineralization, indicating that minerals in coal play an important role in the growth of coal-based CNTs.carbon powder

A silicon carbide nanowire field effect transistor for DNA detection

sakurajun — Wed, 02 Dec 2020 08:15:05 GMT

This work reports on the label-free electrical detection of DNA molecules for the first time, using silicon carbide (SiC) silicon carbide distributorsas a novel material for the realization of nanowire field effect transistors (NWFETs). SiC is a promising semiconductor for this application due to its specific characteristics such as chemical inertness and biocompatibility. Non-intentionally n-doped SiC NWs are first grown using a bottom-up vapor-liquid-solid (VLS) mechanism, leading to the NWs exhibiting needle-shaped morphology, with a length of approximately 2 μm and a diameter ranging from 25 to 60 nm. Then, the SiC NWFETs are fabricated and functionalized with DNA molecule probes via covalent coupling using an amino-terminated organosilane. The drain current versus drain voltage (I d-V d) characteristics obtained after the DNA grafting and hybridization are reported from the comparative and simultaneous measurements carried out on the SiC NWFETs, used either as sensors or references. As a representative result, the current of the sensor is lowered by 22% after probe DNA grafting and by 7% after target DNA hybridization, while the current of the reference does not vary by more than ±0.6%. The current decrease confirms the field effect induced by the negative charges of the DNA molecules. Moreover, the selectivity, reproducibility, reversibility and stability of the studied devices are emphasized by de-hybridization, non-complementary hybridization and re-hybridization experiments. This first proof of concept opens the way for future developments using SiC-NW-based sensors.abrasive manufacturer

Adsorption of arsenic from micro-polluted water by an innovative coal-based mesoporous activated carbon in the presence of co-existing ions

sakurajun — Mon, 30 Nov 2020 08:41:33 GMT

A novel, multi-step procedure was introduced to prepare an innovative coal-based activated carbon (M-NCPAC)coal pellet active carbon in the present work. The adsorption characteristics of As(III)/As(V) ions in low concentrations (0.5 mg/L) from an As(III)/As(V) system were studied at 4 °C. The effects of co-existing Cr(VI) on arsenic adsorption by M-NCPAC were also determined as a function of pH, contact time and adsorbent dose in an arsenic-Cr(VI) system. The results suggested that M-NCPAC has well-developed porosity and absorption ability, such as high pore volume (1.1495 cm3/g), mesoporosity (64.22%), iodine numbers (1137 mg/g), and methylene blue (244 mg/g). The optimum pH for arsenic adsorption was identified as 6. M-NCPAC was proven to be a promising adsorbent (Qm,As(III) = 1.634 mg/g, Qm,As(V) = 1.701 mg/g) in the As(III)/As(V) system. Arsenic adsorption was suppressed in the arsenic-Cr(VI) system, and Qm,As(III) and Qm,As(V) at the optimum pH decreased by 18.23% and 11.06%, respectively. Arsenic adsorption on M-NCPAC in different systems obeyed the pseudo-second-order equation. The effects of four anions on arsenic adsorption were also evaluated either in an As(III)/As(V) system or in an arsenic-Cr(VI) system. The degrees of influence on arsenic adsorption decreased in the following order: phosphate > silicate > carbonate > sulfate. However, chromium species lowered the competitive adsorption between arsenic species and co-existing anions in the arsenic-Cr(VI) system.wood carbon powder

Modeling trichloroethylene adsorption by activated carbon preloaded with natural dissolved organic matter using a modified IAST approach

sakurajun — Mon, 30 Nov 2020 08:40:39 GMT

A model was developed, using an approach based on the Ideal Adsorbed Solution Theory (IAST), to predict trichloroethylene (TCE) adsorption by granular activated carbon (GAC)granular-activated-carbon.com preloaded with natural dissolved organic matter (DOM) isolated from three surface water sources. The IAST model was formulated for a bi-solute system in which TCE and DOM single-solute uptakes were described by the Langmuir-Freundlich and Freundlich isotherms, respectively. The effect of DOM molecular size and polarity (as measured by XAD 8 resin fractionation) on TCE uptake by preloaded GAC was assessed to identify a reactive fraction of natural water DOM for the purpose of modeling competitive adsorption. Consistent with previous work that identified low molecular weight species as the most reactive with regard to preloading effects (i.e., reducing target compound uptake), the low molecular weight components of the polar (hydrophilic) and nonpolar (hydrophobic) DOM fractions, isolated using ultrafiltration (1 kDa molecular weight cutoff membrane), exhibited significant competitive effects. Furthermore, the effects of these fractions on TCE uptake were similar; therefore, theywere considered together to represent a single "reactive fraction" of DOM. On the basis of this finding, isotherms for the <1 kDa low molecular weight DOM fraction of the whole water were measured, and molar concentrations were computed based on an average molecular weight determined using size-exclusion chromatography. The IAST model was modified to incorporate surface area reduction due to pore blockage by DOM and to reflectthe hypothesis thatTCE molecules can access adsorption sites which humic molecules cannot, thus preventing competition on these sites. The model was calibrated with data for TCE uptake by carbon preloaded with the <1 kDa low molecular weight DOM fraction and was verified by predicting TCE uptake by carbon preloaded with whole natural waters for both constant GAC dose (hence constant DOM loading) and variable GAC dose (hence variable DOM loading) TCE isotherms. Preloading by DOM reduced volume in GAC pores having widths smaller than 1.25 nmactivated carbon south africa (likely accessible only to TCE) to a greater extent than total pore volume, suggesting preferential blockage of micropores. Such preferential pore blockage may explain, in part, why increased DOM loading decreases the fraction of the total surface area on which no competition between TCE and DOM occurs.

Performance of biomorphic Silicon Carbide as particulate filter in diesel boilers

sakurajun — Mon, 30 Nov 2020 08:39:36 GMT

Biomorphic Silicon Carbide (bioSiC) carbide silicon is a novel porous ceramic material with excellent mechanical and thermal properties. Previous studies have demonstrated that it may be a good candidate for its use as particle filter media of exhaust gases at medium or high temperature. In order to determine the filtration efficiency of biomorphic Silicon Carbide, and its adequacy as substrate for diesel particulate filters, different bioSiC-samples have been tested in the flue gases of a diesel boiler. For this purpose, an experimental facility to extract a fraction of the boiler exhaust flow and filter it under controlled conditions has been designed and built. Several filter samples with different microstructures, obtained from different precursors, have been tested in this bench. The experimental campaign was focused on the measurement of the number and size of particles before and after placing the samples. Results show that the initial efficiency of filters made from natural precursors is severely determined by the cutting direction and associated microstructure. In biomorphic Silicon Carbide derived from radially cut wood, the initial efficiency of the filter is higher than 95%. Nevertheless, when the cut of the wood is axial, the efficiency depends on the pore size and the permeability, reaching in some cases values in the range 70-90%. In this case, the presence of macropores in some of the samples reduces their efficiency as particle traps. In continuous operation, the accumulation of particles within the porous media leads to the formation of a soot cake, which improves the efficiency except in the case when extra-large pores exist. For all the samples, after a few operation cycles, capture efficiency was higher than 95%. www.hslabrasive.comThese experimental results show the potential for developing filters for diesel boilers based on biomorphic Silicon Carbide.

Increased Recovery of Gold Thiosulfate Alkaline Solutions by Adding Thiol Groups in the Porous Structure of Activated Carbon

sakurajun — Sat, 28 Nov 2020 08:55:46 GMT

wanyang carbon Thiosulfate leaching combined with ion-exchange resins is an innovative alternative for gold recovery. According to the properties of activated carbon, it could replace resins in the gold recovery process, improve efficiency, and reduce operating cost. In this research, the adsorption process of gold thiosulfate complex on thiol-modified activated carbon was studied. Thioglycolic acid (ATG) was impregnated in activated carbon, and its adsorption ability was tested with synthetic solutions of gold and sodium thiosulfate (Au 10 mg·L-1, Na2S2O3 0.1 mol·L-1, pH = 10.0). Carbon was characterized by infrared spectroscopy, SEM-EDS, PZC titration, hardness number measures, and proximal analysis. Synthetic solutions were also characterized by UV-vis spectroscopy and cyclic voltammetry. The percentage of volatile material increased from 10.0 to 13.9% due to the impregnation process of ATG. Infrared spectra show characteristic bands of C-H, S-H, and C-S bonds. In the adsorption tests, the ATG-impregnated carbon achieved 91% of gold recovery, while the same amount of ATG in the liquid phase stirred with unmodified activated carbon reached 90% of gold recovery. The 44.9% of gold recovered with activated carbon impregnated with ATG was eluted with sodium cyanide ([NaCN] = 0.2 mol·L-1; [NaOH] = 0.25 mol·L-1; [CH3CH2OH] = 30% V/V; pH = 12.0; t = 24 h). activated carbon for gold extractionThese results suggest the gold transferred from the thiosulfate complex to a new gold thiolate complex.

Effect of Powdered Activated Carbon as Advanced Step in Wastewater Treatments on Antibiotic Resistant Microorganisms

sakurajun — Sat, 28 Nov 2020 08:54:07 GMT

https://www.powdered-activated-carbon.com

Background: Conventional wastewater treatment plants discharge significant amounts of antibiotic resistant bacteria and antibiotic resistance genes into natural water bodies contributing to the spread of antibiotic resistance. Some advanced wastewater treatment technologies have been shown to effectively decrease the number of bacteria. Nevertheless, there is still a lack of knowledge about the effectiveness of these treatments on antibiotic resistant bacteria and antibiotic resistant genes. To the best of our knowledge, no specific studies have considered how powdered activated carbon (PAC) treatments can act on antibiotic resistant bacteria, although it is essential to assess the impact of this wastewater treatment on the spread of antibiotic resistant bacteria.

Methods: To address this gap, we evaluated the fate and the distribution of fluorescent-tagged antibiotic/ antimycotic resistant microorganisms in a laboratory-scale model simulating a process configuration involving powdered activated carbon as advanced wastewater treatment. Furthermore, we studied the possible increase of naturally existing antibiotic resistant bacteria during the treatment implementing PAC recycling.

Results: The analysis of fluorescent-tagged microorganisms demonstrated the efficacy of the PAC adsorption treatment in reducing the load of both susceptible and resistant fluorescent microorganisms in the treated water, reaching a removal efficiency of 99.70%. Moreover, PAC recycling did not increase the resistance characteristics of cultivable bacteria neither in the sludge nor in the treated effluent.

Conclusion: Results suggest that wastewater PAC treatment is a promising technology not only for the removal of micropollutants but also for its effect in decreasing antibiotic resistant bacteria release.yongruida granular activated carbon

CdS loaded on coal based activated carbon nanofibers with enhanced photocatalytic property

sakurajun — Sat, 28 Nov 2020 08:53:07 GMT

The coal based activated carbon nanofibers (CBACFs)www.coalactivatedcarbon.comwere prepared by electrospinning a mixture of polyacrylonitrile (PAN) and acid treated coal. Cadmium sulfide (CdS) nanoparticles loaded on CBACFs were fabricated by solvothermal method. The obtained samples were characterized by FESEM, TEM, and XRD. The results reveal that the CdS nanoparticles are homogeneously dispersed on the surfaces of CBACFs. The CdS/CBACFs nanocomposites exhibited higher photoactivity for photodegradation of methyl blue (MB) under visible light irradiation than pure CdS nanoparticles. CBACFs can be used as low cost support materials for the preparation of nanocomposites with high photocatalytic activity.

Graphical abstractactivated carbon supplier
The coal based activity carbon nanofibers (CBACFs) were prepared by electrospinning a mixture of polyacrylonitrile (PAN) and acid treated coal. Cadmium sulfide (CdS) nanoparticles loaded on CBACFs were fabricated by solvothermal method. The CdS/CBACFs nanocomposites exhibited outstanding photocatalytic activity.

Activated carbons from bituminous coals by reaction with H3PO4: The influence of coal cleaning

sakurajun — Fri, 27 Nov 2020 09:06:30 GMT

A study has been made to examine the effects of coal cleaning by column flotation on the properties of carbons prepared by the phosphoric acid activation of bituminous coals. www.coalactivatedcarbon.com Earlier work has shown that while moderate surface areas are generated by the reaction of coals with H3PO4 at temperatures around 550°C, phosphoric acid also reacts with coal sulfur and mineral matter. These side reactions consume reagent that is otherwise available for reaction with the organic structure, and result in the formation of insoluble phosphates, increasing the carbon ash content and limiting the amount of recoverable reagent. Lowering the mineral matter content of the coals prior to carbon synthesis is found to have a direct influence on reducing the ash content of the derived carbons and the extent of phosphorus retention. Coal cleaning also increases the extent of sulfur removal (most of which is liberated as H2S), the BET and mesopore surface areas, and the carbon pore volume. Possible causes of these effects are discussed. The assumption that the ash in the carbon has negligible porosity, and hence that the reduction in mineral matter content of the coal will automatically increase the specific surface area of the carbon by lowering the ash content, does not appear to fully explain the results. The consumption of phosphoric acid by side reactions lowers the effective reagent to coal ratio and limits the amount of available reagent, which can cause a reduction in surface area. Further, it is possible that ash constituents can block the pore structure, and that lowering the coal mineral matter content will improve access.activated carbon supplier It seems probable that all three explanations have some validity and can contribute to the observed changes.