The augmented demands of textile materials over time have brought challenges in the disposal of substantial volumes of waste generated during the processing and end of life of such materials. Taking into consideration environmental safety due to discarding of textile waste, it becomes critical to recuperate useful products from such waste for economic reasons. The present work deals with the preparation of porous and electrically conductive activated carbon fabric by a novel single stage method of simultaneous carbonization and physical activation of Kevlar feedstock material procured from local industries, for effective electromagnetic (EM) shielding applications. The Kevlar fabric waste was directly carbonized under a layer of charcoal without any intermediate stabilization step at 800 °C, 1000 °C, and 1200 °C, with a heating rate of 300 °C/h and without any holding time. The physical and morphological properties of the activated carbon, influenced by carbonization process parameters, were characterized from EDX, X-ray diffraction, SEM analysis, and BET analysis. Furthermore, the electrical conductivity was analyzed. Finally, the potential application of the activated material for EM shielding effectiveness was analyzed at low (below 1.5 GHz) and high (2.45 GHz) frequencies. The phenomena of multiple internal reflections and absorption of electromagnetic radiations was found dominant in the case of activated carbon fabric produced at higher carbonization temperatures.

• Klíčová slova
• EMI shielding, Kevlar, activated carbon, carbonization, cost effective, electrical conductivity, porous surface, recycle, textile waste,
• Publikační typ
• časopisecké články MeSH

Three adsorbents, calcium alginate beads (AB), sodium hydroxide activated carbon based coconut shells (C), and calcium alginate/activated carbon composite beads (ACB) were prepared. Their textural properties were characterized by N2-adsorption at -196°C and scanning electron microscopy. The porosity, surface area and total pore volume of C>ACB>AB, but AB adsorbent was more acidic function groups more than the other adsorbents. Adsorption experiments were conducted to examine the effects of adsorbent dosage, pH, time, temperature and initial concentration of methylene blue. Methylene blue adsorption on C, AB and ACB was observed at pH>6 to avoid the competition of H(+). The amount of dye adsorbed increases as the adsorbent dosage increase. Adsorption of dye follows pseudo-second order mechanism. Thermodynamic studies show spontaneous and endothermic nature of the overall adsorption process.

• Klíčová slova
• Activated carbon, Alginate beads, Coconut shells, Composite, Methylene blue,
• Publikační typ
• časopisecké články MeSH

Radiation therapy along with chemotherapy and surgery remain the main cancer treatments. Radiotherapy can be applied to patients externally (external beam radiotherapy) or internally (brachytherapy and radioisotope therapy). Previously, nanoencapsulation of radioactive crystals within carbon nanotubes, followed by end-closing, resulted in the formation of nanocapsules that allowed ultrasensitive imaging in healthy mice. Herein we report on the preparation of nanocapsules initially sealing "cold" isotopically enriched samarium (152Sm), which can then be activated on demand to their "hot" radioactive form (153Sm) by neutron irradiation. The use of "cold" isotopes avoids the need for radioactive facilities during the preparation of the nanocapsules, reduces radiation exposure to personnel, prevents the generation of nuclear waste, and evades the time constraints imposed by the decay of radionuclides. A very high specific radioactivity is achieved by neutron irradiation (up to 11.37 GBq/mg), making the "hot" nanocapsules useful not only for in vivo imaging but also therapeutically effective against lung cancer metastases after intravenous injection. The high in vivo stability of the radioactive payload, selective toxicity to cancerous tissues, and the elegant preparation method offer a paradigm for application of nanomaterials in radiotherapy.

• Klíčová slova
• cancer therapy, filled carbon nanotubes, nanoencapsulation, nanooncology, nuclear imaging, radiooncology,
• MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nádory plic diagnostické zobrazování   radioterapie   MeSH
• nanokapsle chemie   MeSH
• neutrony * MeSH
• povrchové vlastnosti MeSH
• samarium chemie   MeSH
• uhlík chemie   MeSH
• velikost částic MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nanokapsle MeSH
• samarium MeSH
• uhlík MeSH

This research deals with the removal of Cr(VI), one of the most toxic heavy metal in biological systems, from wastewater by using activated carbon produced via pyrolysis and chemical activation of "Posidonia oceanica". That is the most important and well-studied seagrass species of the Mediterranean Sea. The as produced activated carbon exhibited high specific surface area up to 1563 m2/g and a cumulative pore volume of 0.74 cm3/g, allocated to 74% micro-pores and 26% to meso-macro- pores. The adsorption capacity of Cr(VI) into Posidonia oceanica activated carbon was studied via batch experiments considering the contact time, the initial concentration and the pH parameters. The results were interpreted using four different adsorption kinetic models. The activated carbon material seems to exhibit excellent sorption properties with rapid removal capability for Cr(VI). The estimated maximum uptake capacity at equilibrium stage was ~120 mg/g. Also, the initial adsorption rate ri was dependent on the initial Cr(VI) concentration in aqueous solution and it was from 77 mg/(g*h) to 264 mg/(g*h). The best fitted kinetic model seems to be the Diffusion-Chemisorption model with the rate constant KDC of the Cr(VI) ions transfer from liquid to solid particles extend from 52 to 78 mg/(g*h0.5).

• Klíčová slova
• Biomass activated carbon, Charcoal activation, Diffusion-chemisorption mechanism, Hexavalent chromium removal, KOH charcoal activation Agent, Posidonia oceanica,
• MeSH
• adsorpce MeSH
• Alismatales * MeSH
• chemické látky znečišťující vodu * analýza   MeSH
• chrom analýza   MeSH
• dřevěné a živočišné uhlí MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• pyrolýza MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Středozemní moře MeSH
• Názvy látek
• chemické látky znečišťující vodu * MeSH
• chrom MeSH
• chromium hexavalent ion MeSH Prohlížeč
• dřevěné a živočišné uhlí MeSH

In view of the urgent need for tertiary treatment of papermaking wastewater and the difficulty in separating powdered activated carbon (PAC) from water, the magnetic activated carbon (33%-MPAC, 50%-MPAC and 67%-MPAC) were prepared by chemical coprecipitation method for adsorption of biologically treated papermaking wastewater (BTPW). A series of characterization of MPAC and PAC were carried out and show that the content of iron oxides is negatively related to the proportion of micropores in MPAC. The loaded iron oxides is mainly the mixture of magnetite and maghemite, and the maximum saturation magnetization of MPAC can reach 29.68 emu/g. Batch mode experiments were performed, and found that the adsorption effect of MPAC is slightly worse than that of PAC, the adsorption capacity of COD in MPAC can reach about 65 mg/g, and pH = 2 and 10 °C are more favorable for adsorption. The adsorption isotherms and kinetics were well fitted by the Freundlich model and pseudo-second-order kinetic model, respectively. The selective adsorption was studied by using the excitation emission matrix (EEM) fluorescence spectrum and high-performance size exclusion chromatography (HPSEC). It is concluded that all adsorbents are preferred to adsorb humic acid-like substances (HA). And all adsorbents are preferred to adsorb low apparent molecular weight substances (LAMW, AMW < 1500 Da), with the increase of iron oxides content, the phenomenon of MPAC preferentially adsorbed LAMW became less obvious.

• Klíčová slova
• Biologically treated papermaking wastewater, EEM fluorescence spectrum, High-performance size exclusion chromatography, Magnetic activated carbon, Selective adsorption,
• MeSH
• adsorpce MeSH
• chemické látky znečišťující vodu MeSH
• čištění vody * MeSH
• dřevěné a živočišné uhlí MeSH
• huminové látky MeSH
• kinetika MeSH
• magnetické jevy * MeSH
• odpadní voda MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chemické látky znečišťující vodu MeSH
• dřevěné a živočišné uhlí MeSH
• huminové látky MeSH
• odpadní voda MeSH

In the current study, activated carbon (AC) was prepared from date palm using single step activation using boric acid as an activating agent. The synthesized AC was incorporated with alginate (AC-alginate (AC-alg)) to prepare membrane for adsorption of methylene blue (MB) in batch adsorption study. The prepared membrane was characterized using different types of analytical techniques such as FTIR, SEM, and TGA analysis. Adsorption of methylene blue dye from aqueous solution was carried out using AC-alg membrane in batch investigation. Various experimental parameters effecting the adsorption of MB on membrane such as initial pH of dye solution, contact time, concentration of dye solution and temperature were optimized to get maximum adsorption efficiency. Kinetics, isotherm and thermodynamics study was performed for dye adsorption. Pseudo-second order kinetic model and Langmuir adsorption isotherm were well fitted to the experimental data. The maximum adsorption capacity for MB adsorption was 666 mg/g found by Langmuir adsorption isotherm. Thermodynamic study revealed that the adsorption of MB on AC-alg membrane is spontaneous and an exothermic process. The experimental result confirmed that AC-alg membrane is a suitable and easily recoverable adsorbent to be used for efficient removal of MB and MB like other dyes.

• Klíčová slova
• Activated carbon, Adsorption, Composite membrane, Isotherm study, Thermodynamic study,
• MeSH
• adsorpce MeSH
• algináty chemie   MeSH
• barvicí látky chemie   MeSH
• chemické látky znečišťující vodu * analýza   MeSH
• dřevěné a živočišné uhlí chemie   MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• methylenová modř chemie   MeSH
• Phoeniceae * MeSH
• termodynamika MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• algináty MeSH
• barvicí látky MeSH
• chemické látky znečišťující vodu * MeSH
• dřevěné a živočišné uhlí MeSH
• methylenová modř MeSH

Adsorption is one of the most successful physicochemical approaches for removing heavy metal contaminants from polluted water. The use of residual biomass for the production of adsorbents has attracted a lot of attention due to its cheap price and environmentally friendly approach. The transformation of Sargassum-an invasive brown macroalga-into activated carbon (AC) via phosphoric acid thermochemical activation was explored in an effort to increase the value of Sargassum seaweed biomass. Several techniques (nitrogen adsorption, pHPZC, Boehm titration, FTIR and XPS) were used to characterize the physicochemical properties of the activated carbons. The SAC600 3/1 was predominantly microporous and mesoporous (39.6% and 60.4%, respectively) and revealed a high specific surface area (1695 m2·g-1). To serve as a comparison element, a commercial reference activated carbon with a large specific surface area (1900 m2·g-1) was also investigated. The influence of several parameters on the adsorption capacity of AC was studied: solution pH, solution temperature, contact time and Cr(VI) concentration. The best adsorption capacities were found at very acid (pH 2) solution pH and at lower temperatures. The adsorption kinetics of SAC600 3/1 fitted well a pseudo-second-order type 1 model and the adsorption isotherm was better described by a Jovanovic-Freundlich isotherm model. Molecular dynamics (MD) simulations confirmed the experimental results and determined that hydroxyl and carboxylate groups are the most influential functional groups in the adsorption process of chromium anions. MD simulations also showed that the addition of MgCl2 to the activated carbon surface before adsorption experiments, slightly increases the adsorption of HCrO4- and CrO42- anions. Finally, this theoretical study was experimentally validated obtaining an increase of 5.6% in chromium uptake.

• Klíčová slova
• activated carbon, adsorption, biomass valorization, hexavalent chromium, molecular dynamics simulation, sargassum,
• MeSH
• adsorpce MeSH
• chemické látky znečišťující vodu * chemie   MeSH
• chrom chemie   MeSH
• dřevěné a živočišné uhlí chemie   MeSH
• dusík MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• Sargassum * MeSH
• simulace molekulární dynamiky MeSH
• voda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chemické látky znečišťující vodu * MeSH
• chrom MeSH
• chromium hexavalent ion MeSH Prohlížeč
• dřevěné a živočišné uhlí MeSH
• dusík MeSH
• voda MeSH

The increasing occurrence of algal and cyanobacterial blooms and the related formation of algal organic matter (AOM) is a worldwide issue that endangers the quality of freshwater sources and affects water treatment processes. The associated problems involve the production of toxins or taste and odor compounds, increasing coagulant demand, inhibition of removal of other polluting compounds, and in many cases, AOM acts as a precursor of disinfection by-products. Previous research has shown that for sufficient AOM removal, the conventional drinking water treatment based on coagulation/flocculation must be often accompanied by additional polishing technologies such as adsorption onto activated carbon (AC). This state-of-the-art review is intended to serve as a summary of the most current research on the adsorption of AOM onto AC concerning drinking water treatment. It summarizes emerging trends in this field with an emphasis on the type of AOM compounds removed and on the adsorption mechanisms and influencing factors involved. Additionally, also the principles of competitive adsorption of AOM and other organic pollutants are elaborated. Further, this paper also synthesizes previous knowledge on combining AC adsorption with other treatment techniques for enhanced AOM removal in order to provide a practical resource for researchers, water treatment plant operators and engineers. Finally, research gaps regarding the AOM adsorption onto AC are identified, including, e.g., adsorption of AOM residuals recalcitrant to coagulation/flocculation, suitability of pre-oxidation of AOM prior to the AC adsorption, relationships between the solution properties and AOM adsorption behaviour, or AOM as a cause of competitive adsorption. Also, focus should be laid on continuous flow column experiments using water with multi-component composition, because these would greatly contribute to transferring the theoretical knowledge to practice.

• Klíčová slova
• Activated carbon, Adsorption, Algal organic matter, Drinking water treatment, Micropollutants,
• MeSH
• adsorpce MeSH
• chemické látky znečišťující vodu * analýza   MeSH
• čištění vody * MeSH
• dezinfekce MeSH
• dřevěné a živočišné uhlí MeSH
• pitná voda * MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• chemické látky znečišťující vodu * MeSH
• dřevěné a živočišné uhlí MeSH
• pitná voda * MeSH

The organochlorine pesticides (OCPs) have raised concerns about being persistent and toxic to the environment. Phytoremediation techniques show promise for the revitalization of polluted soils. The current study focused on optimizing the phytoremediation potential of Miscanthus sinensis And. (M. sinensis), second-generation energy crop, by exploring two soil amendments: Tween 20 and activated carbon (AC). The results showed that when M. sinensis grew in OCP-polluted soil without amendments to it, the wide range of compounds, i.e., α-HCH, β-HCH, γ-HCH, 2.4-DDD, 4.4-DDE, 4.4-DDD, 4.4-DDT, aldrin, dieldrin, and endrin, was accumulated by the plant. The introduction of soil amendments improved the growth parameters of M. sinensis. The adding of Tween 20 enhanced the absorption and transmigration to aboveground biomass for some OCPs; i.e., for γ-HCH, the increase was by 1.2, for 4.4-DDE by 8.7 times; this effect was due to the reduction of the hydrophobicity which made pesticides more bioavailable for the plant. The adding of AC reduced OCPs absorption by plants, consequently, for γ-HCH by 2.1 times, 4.4-DDD by 20.5 times, 4.4-DDE by 1.4 times, 4.4-DDT by 8 times, α-HCH was not adsorbed at all, and decreased the translocation to the aboveground biomass: for 4.4-DDD by 31 times, 4.4-DDE by 2.8 times, and γ-HCH by 2 times; this effect was due to the decrease in the bioavailability of pesticides. Overall, the amendment of OCP-polluted soil by Tween 20 speeds the remediation process, and incorporation of AC permitted to produce the relatively clean biomass for energy.

• Klíčová slova
• Activated carbon, Miscanthus sinensis And., Organochlorine pesticides, Phytoremediation, Sequestration, Tween 20,
• MeSH
• biodegradace MeSH
• chlorované uhlovodíky * analýza   MeSH
• dřevěné a živočišné uhlí MeSH
• látky znečišťující půdu * analýza   MeSH
• monitorování životního prostředí MeSH
• pesticidy * analýza   MeSH
• polysorbáty MeSH
• půda MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chlorované uhlovodíky * MeSH
• dřevěné a živočišné uhlí MeSH
• látky znečišťující půdu * MeSH
• pesticidy * MeSH
• polysorbáty MeSH
• půda MeSH

Waste scrap tyres were thermally decomposed at the temperature of 600 °C and heating rate of 10 °C·min-1. Decomposition was followed by the TG analysis. The resulting pyrolytic carbon black was chemically activated by a KOH solution at 800 °C. Activated and non-activated carbon black were investigated using high pressure thermogravimetry, where adsorption isotherms of N2, CO2, and cyclohexane were determined. Isotherms were determined over a wide range of pressure, 0.03-4.5 MPa for N2 and 0.03-2 MPa for CO2. In non-activated carbon black, for the same pressure and temperature, a five times greater gas uptake of CO2 than N2 was determined. Contrary to non-activated carbon black, activated carbon black showed improved textural properties with a well-developed irregular mesoporous-macroporous structure with a significant amount of micropores. The sorption capacity of pyrolytic carbon black was also increased by activation. The uptake of CO2 was three times and for cyclohexane ten times higher in activated carbon black than in the non-activated one. Specific surface areas evaluated from linearized forms of Langmuir isotherm and the BET isotherm revealed that for both methods, the values are comparable for non-activated carbon black measured by CO2 and for activated carbon black measured by cyclohexane. It was found out that the N2 sorption capacity of carbon black depends only on its specific surface area size, contrary to CO2 sorption capacity, which is affected by both the size of specific surface area and the nature of carbon black.

• Klíčová slova
• CO2, N2, carbon black, cyclohexane, sorption, waste scrap tyres,
• MeSH
• dusík chemie   MeSH
• odpadky - odstraňování * MeSH
• oxid uhličitý analýza   MeSH
• saze chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusík MeSH
• oxid uhličitý MeSH
• saze MeSH