Synthesis of an ordered mesoporous carbon with graphitic characteristics and its application for dye adsorption

An ordered mesoporous carbon (OMC) was prepared by a chemical vapor deposition technique using liquid petroleum gas (LPG) as the carbon source. During synthesis, LPG was effectively adsorbed in the ordered mesopores of SBA-15 silica and converted to a graphitic carbon at 800 °C. X-ray diffraction and nitrogen adsorption/desorption data and high-resolution transmission electron microscopy (HRTEM) of the OMC confirmed its ordered mesoporous structure. The OMC was utilized as an adsorbent in the removal of dyes from aqueous solution. A commercial powder activated carbon (AC) was also investigated to obtain comparative data. The efficiency of the OMC for dye adsorption was tested using acidic dye acid orange 8 (AO8) and basic dyes methylene blue (MB) and rhodamine B (RB). The results show that adsorption was affected by the molecular size of the dye, the textural properties of carbon adsorbent and surface-dye interactions. The adsorption capacities of the OMC for acid orange 8 (AO8), methylene blue (MB) and rhodamine B (RB) were determined to be 222, 833, and 233 mg/g, respectively. The adsorption capacities of the AC for AO8, MB, and RB were determined to be 141, 313, and 185 mg/ g, respectively. The OMC demonstrated to be an excellent adsorbent for the removal of MB from wastewater.Web of Scienc

Activated Carbons from Solid Residue from Fast Pyrolysis of Biomass

Zbadano węgle aktywne otrzymane ze stałej pozostałości po szybkiej pirolizie biomasy celulozy (C) i trocin (T) oraz ich mieszanek z polimerami syntetycznymi: celulozy/polistyrenu (3:1) (CPS), celulozy/polipropylenu (3:1)(CPP) oraz trocin/polistyrenu (3:1) (TPS) i trocin/polipropylenu (3:1) (TPP). Węgle aktywne otrzymano na drodze aktywacji parą wodną w temperaturze 850°C do 50% ubytku masy. Węgle scharakteryzowano, opierając się na analizie technicznej, elementarnej oraz sorpcji azotu w −196°C. Dodatkowo dla wybranych węgli aktywnych przeprowadzono adsorpcję fenolu, czerwieni Kongo i witaminy B12. Adsorpcję wykonano w warunkach statycznych w temperaturze pokojowej. Wyznaczono czasy osiągania stanu równowagi oraz pojemność sorpcyjną. Wszystkie otrzymane węgle aktywne wykazały zasadowy charakter chemiczny powierzchni. Węgle otrzymane z celulozy są to typowo mikroporowate węgle aktywne, podczas gdy węgle aktywne z trocin charakteryzowały się dobrze rozwiniętą strukturą mikro- i mezoporowatą.The activated carbons (ACs) were produced from solid residue of cellulose and synthetic polymer co-pyrolysis and sawdust and polymer co-pyrolysis. The solid residues of a mixture of cellulose/polystyrene (3:1) (CPS), sawdust/polystyrene (3:1) (TPS), cellulose/polypropylene (3:1) (CPP), sawdust/polypropylene (3:1) (TPP), and only cellulose (C) only sawdust (T) have been produced in two steps pyrolysis. In the first step the sample is slowly heated up to 400°C with heating rate 3°C/minutes and next the second step is the fast pyrolysis with heating rate 100°C/second up to 900°C. The ACs have been obtained by steam activation at 850°C up to about 50% burn off. The elemental analysis of C, H, N and S was performed using a Vario III Elemental Analyzer. The oxygen content was calculated by difference. The porous texture was determined from nitrogen adsorption isotherms measured at −196°C with a NOVA 2200 (Quantachrome). For a chosen activated carbon the adsorptive properties toward phenol, Congo red, and vitamin B12 have been determined. The adsorption processes were carried out in static condition at ambient temperature. The equilibrium time and equilibrium sorption capacity were determined. All obtained ACs have basic surface characteristics. The cellulose based activated carbons are predominantly microporous whereas the sawdust based AC have well developed both micro and mesoporous structure. Activated carbon from cellulose has high adsorption capacity toward phenol whereas AC from sawdust is found to be very efficient adsorbent for the removal of Congo red and vitamin B12. Additionally, the adsorption of phenol and Congo red was enhanced by electrostatic forces that appeared between the adsorbed molecules and activated carbon surface

Phenol Removal on Anthracene Pitch-based Activated Carbon

W pracy zbadano zdolność węgla aktywnego otrzymanego z paku antracenowego do adsorpcyjnego usuwania fenolu. W celach porównawczych zastosowano również komercyjny węgiel aktywny otrzymany z łupin orzecha kokosowego. Węgle scharakteryzowano w oparciu o analizę techniczną, elementarną oraz sorpcję azotu w 77 K. Badane węgle są węglami typowo mikroporowatymi. Adsorpcję fenolu przeprowadzono w warunkach statycznych w temperaturze pokojowej. Wyznaczono czasy osiągania stanu równowagi oraz nadmiarowe izotermy adsorpcji, które scharakteryzowano w oparciu o równania Langmuira i Freundlicha. Stwierdzono, że węgle aktywne otrzymane z paku adsorbują fenol lepiej niż komercyjny węgiel aktywny. Zaobserwowano, że sorpcja w monowarstwie wyznaczona z równania Langmuira zależy od objętości porów o szerokości mniejszej niż 1,4 nm.The adsorptive properties of anthracene pitch-based powder activated carbons (AACs) towards the phenol removal have been studied. The AACs were prepared by steam or CO2 activation of the preoxidized precursor. Different methods of pitch preoxidation were used, i.e. air oxidation and wet oxidation with mixture of sulfuric/nitric acid, and sulfuric acid/peroxide. For comparison the commercial activated carbon from coconut shell has been used (OK). The studied ACs have been characterized in terms of proximate, elemental analysis and porous texture. The studied activated carbons are predominantly microporous. The AACs are almost ash free with slightly acidic surface characteristics. The OK has low ash content and slightly basic surface characteristics. The heteroatoms content N+O is comparable for AACs whereas the OK has the lowest heteroatom content. The phenol adsorption processes were carried out in static condition at ambient temperature. The equilibrium time and equilibrium sorption isotherms were determined. The equilibrium time varied from 8 to 48 hours. The Langmuir and Freundlich models were applied to interpret the data. The sorption capacity of AACs was twofold higher than the sorption capacity of the commercial OK. The correlation between the Langmuir sorption capacity and volume of pores smaller than 1.4 nm were observed