Activated Carbon
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Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1456
Author(s):  
Brahim Samir ◽  
Soumia Bakhta ◽  
Nabil Bouazizi ◽  
Zahra Sadaoui ◽  
Ouiza Allalou ◽  
...  

This study reports on the synthesis, immobilization, and stabilization of iron (Fe) particles in activated carbon (AC) from date stem material for the heterogeneous Fenton-like removal of hazardous pollutants from water. AC-Fe was synthesized through a simple and sustainable chemical reaction using and resulting in an environmentally friendly material (AC-Fe). X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray analyses (EDX) were used to characterize the synthesized samples. XRD, FTIR and XPS results showed the successful incorporation of iron particles onto AC. SEM images indicated smooth surfaces with clearly visible Fe particles. Compared to pure AC, AC-Fe showed higher degradation rates of toluidine blue O (TBO) dye. The effects of the initial pH and TBO and H2O2 concentrations on TBO degradation were investigated. The AC-Fe catalyst proved highly efficient in the Fenton-like degradation of TBO (50 ppm), with the removal of up to 99% in 3 min. This catalyst was used efficiently for up to four repeated cycles. The improved catalytic activity of AC-Fe was related to Fe particles for the generation of HO•. These results prove that date stems—a waste product from agriculture—are a suitable precursor for preparing an appropriate AC and catalyst and for eliminating dyes from an aqueous solution by a heterogeneous Fenton-like reaction. The above results open an interesting avenue for the development of functional green catalysts based on AC-Fe for pollution removal.


Author(s):  
S. A. Adesokan ◽  
A. A. Giwa ◽  
I. A. Bello

Daniellia—oliveri sawdust-based adsorbents were employed to remove trimethoprim (TMP) from water. The sawdust was thermally carbonized and activated in-stu with ZnCl2 and H3PO4 separately. The adsorbents surface features were profiled using scanning electron microscopic (SEM) and pH point of zero charge (pHpzc ) analyses. The prospects of the adsorbents for the removal of trimethoprim from water were verified. The adsorption processes were performed under different experimental conditions. The adsorption isotherm, the kinetics, and the thermodynamics were studied; and the data fitting output revealed that both chemisorptions and physisorption occurred. Surface and pore diffusion played active role in the adsorption of TMP by the adsorbents. The optimum conditions for adsorption of TMP by the adsorbents were pH at slightly acidic to neutral medium and temperature at room temperature. The fitting isotherm models were: Langmuir (R2 = 0.993) for the zinc-chloride-activated-carbon, Temkin (R2 = 0.962) for the phosphoric-acid-activated-carbon, and the kinetics: pseudo-second order (R2 = 0.997) for both. The maximum monolayer adsorption capacities of the adsorbents for TMP was 4.115 and 6.495 mg/g, respectively. The thermodynamic parameters determined suggested feasibility, spontaneity, and endothermicity of the adsorption processes. The results reveal that the adsorbents were goodprospects for the removal of TMP from water.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Seyyed Alireza Mousavi ◽  
Davood Shahbazi ◽  
Arezoo Mahmoudi ◽  
Parviz Mohammadi ◽  
Tooraj Massahi

The efficiency of activated carbon produced from grape waste as a low-cost, nontoxic, and available adsorbent to remove Reactive Red 2 from aqueous solution has been investigated. The prepared activated carbon has been characterized by FTIR, SEM, and BET. The results of characterization indicate the successful conversion of grape waste into mesoporous AC with desirable surface area consist of different functional groups. The results of statistical modeling displayed high R 2 value of 0.97% for dye removal that shows the developed model has acceptable accuracy. The effect of independent variables indicated that the highest adsorption (96.83%) obtained at pH 3, adsorbent dosage of 12.25 g/L, and initial dye concentration of 100 mg/L when the adsorption time was 90 min. The results of isotherms modeling showed that the data fit well with the Langmuir (type II). The kinetic studies using pseudofirst-order and pseudosecond-order models pointed out that the type (I) of pseudosecond-order kinetic model provided the best fit to the adsorption data. Parameters of thermodynamics including Gibbs energy ( Δ G ° ) and k o were calculated. The values of Δ G ° indicated that the dye adsorption of RR2 is spontaneous. The agricultural wastes due to special points such as low-cost, availability, and high ability to produce an adsorbent with high efficiency to remove dye can be proposed for water and wastewater treatment.


2021 ◽  
Vol 59 (12) ◽  
pp. 911-920
Author(s):  
Young Mook Choi ◽  
Sang-Eun Chun

Supercapacitor electrode slurry is prepared for mass production by mixing activated carbon powder, conductive agent, and binder, which is then deposited on a substrate using the doctor-blade method. Polyvinylidene fluoride (PVDF) and 1-methyl-2-pyrrolidone (NMP) are used as binder and solvent, respectively, to form the electrode slurry on a metal substrate. In this study, ethyl cellulose (EC) is evaluated as a binder to prepare an electrode on an indium-tin-oxide (ITO) substrate obtaining transparent supercapacitors. Terpineol and isopropyl alcohol (IPA) are compared as suitable solvents for the EC binder. When terpineol is employed as a solvent, the conductive agent is uniformly deposited around the activated carbon powder. An electrode prepared using EC and terpineol exhibits slightly lower specific capacitance and rate performance than that using conventional PVDF and NMP. However, the electrode prepared using EC and terpineol securely adheres to the electrode components, resulting in a robust electrode. In contrast, an electrode prepared using EC and IPA exhibits high charge transfer resistance at the interface of the electrode/electrolyte, leading to a low specific capacitance and rate performance. Thus, ecofriendly EC and terpineol can substitute the conventional PVDF and NMP for depositing activated carbon powder on an ITO substrate, while improving the specific capacitance of manufactured electrodes.


Author(s):  
María A. Aguilar Morales ◽  
Armandina De la Cruz Olvera ◽  
E. Archundia-Garduño ◽  
Rosy G. Cruz Monterrosa ◽  
Mayra Díaz-Ramírez ◽  
...  

Objective: The objective of this study was to establish the method of propagation of Oryganum vulgare and Lippia graveolens employing a plant tissue culture technique that decreased the phenolization percentages and increased the multiplication coefficients. Design/ methodology/ approach: The in vitro germination percentage was evaluated in both MS and MS medium + activated carbon. Microcuttings (small shoots) of both species were established in base medium added with different antioxidant agents to decrease the phenolization of explants; the treatments were arranged in a completely randomized block  design. For the propagation phase, a completely randomized factorial design was used, where the auxin/cytokinin phytoregulators, type of explants (axillary buds and leaves), and the species (Lippia graveolens and Oryganum vulgare)  were considered as factors. Results: maximum germination (63.3% ±12.5) was obtained on day 15 ​​in both culture media for L. graveolens and O. vulgare. The use of antioxidant agents mainly activated carbon, increased the in vitro establishment and activation of vegetative buds in both species by up to 90%. There were significant differences in the variables evaluated regarding the treatments, the explant, and the species in the multiplication phase. The combination 1.0/ 0.5 mg L-1 BA/AIB induces callus formation for both species. When used as leaf explants, callus formation was potentiated. Study Limitations / Implications: The results presented are advances from a long-term experiment. Findings/conclusions: The germination of L. graveolens seeds can be achieved in MS medium after 15 days. Microcuttings of both L. graveolens and O. vulgare were successfully established in MS basal medium enriched with 1 g L-1 charcoal that showed low oxidation percentages and induced up to 90% the production of shoots in the explants. The mixture of 1.0/0.5 mg L-1 BA/AIB induces callus formation for both species; when this medium is in contact with leaves as an explant, its formation is potentiated, achieving diameters up to 15 mm. In order to achieve the induction of shoots and roots, buds should be established in MS medium enriched with 0.5 mg L-1 IBA for both species; this mixture encreased the multiplication coefficients


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yigezu Mekonnen Bayisa ◽  
Tafere Aga Bullo ◽  
Desalegn Abdissa Akuma

Abstract Objective In tannery processing, water consumption is high, which generates wastewater as a by-product and numerous pollutants such as chromium heavy metals that make adverse effects of water bodies and the surrounding environment. This study analyzed, chromium (VI) removal from wastewater through activated carbon chat stem was investigated. Adsorption is a common treatment method via activated carbon due to its cost-effective, profitable, and removal efficiency of these heavy metals. Results The proximate analysis of moisture content of chat stem has 6%, activated carbon ash content of 17.35%, volatile materials of 20.12%, and fixed carbon contents of 56.53%, which are well-matched the standards quality of activated carbon. As the process parameter varies, the increment of the chromium removal efficiency was from 62.5 to 97.03%. The maximum adsorption efficiency was observed at 30 g/L dosage of the adsorbent, at pH 4, and contact time at 180 min of activated carbon from chat stem waste was found 97.03%. FTIR was used to characterize the surface of the chat stem before and after adsorption. Langmuir and Freundlich are used for short contact time’s adsorption isotherm 0.9839 and 0.9995 respectively, which conformed, no visible change in the corrosion state.


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