Hydrogen sorption characteristics of Zonguldak region coal activated by physical and chemical methods

Abstract

Hydrogen sorption characteristics of activated carbons (ACs) produced by physical and chemical activations from two coal mines (Kilimli and Armutcuk) in the Zonguldak region, Turkey were investigated by a volumetric technique at 77 K. H 2 adsorption isotherms were obtained on the samples exposed to pyrolytic thermal treatments in a temperature range of 600-900 o C under N 2 flow and chemical activation using different chemical agents such as KOH, NH 4 Cl, ZnCl 2 from the two mines. Experimental hydrogen adsorption isotherm data at 77 K were used for the evaluation of the adsorption isotherm constants of the Brunauer-Emmett-Teller (BET) and the Langmuir models, and also the amount of hydrogen adsorbed on the various samples was evaluated by using the adsorption isotherm data. Higher hydrogen adsorption capacity values were obtained for all the heat and the chemically treated activated carbon samples from the Kilimli coal samples than Armutcuk. The amount of H 2 adsorbed on the original Kilimli coal samples was 0.020 wt%, and it was increased to 0.89 wt% on the samples pyrolyzed at 800 o C. The highest value of hydrogen adsorption obtained was 1.2 wt% for the samples treated with KOH+NH 4 Cl mixture at 750 o C followed by oxidation with ZnCl 2 . It was shown that chemical activations were much more effective than physical activations in increasing the surface area, pore volume and the hydrogen sorption capacities of the samples.

Examination of sorption and desorption of hydrogen on several samples of polish hard coals

“…Experiments were conducted at 77 K in pressure range up to 760 mm Hg by measuring sorption on hard coals and activated carbons derived from them (Kopac and Toprak 2009). Many time larger capacity of hydrogen sorption on activated carbons than on hard coals was observed.…”

Hydrogen storage characteristics of bio‐based porous carbons of different origin: A comparative review

“…AC has been used as adsorbent in many applications for centuries due being a low cost and a high adsorption capacity material. 21,51,52 Comparing with other sorption materials, it has better chemical stability, higher surface area, good porous structure, high packing density, easy availability, showing fast and reversible kinetics, which makes it a favorable material for hydrogen storage applications as well. 53 Varieties of ACs with enhanced properties can be prepared by chemical activation.…”

An analysis of burn-off impact on the structure microporous of activated carbons formation

“…The middle of the 20 th century saw a growing interest in hard coal, or anthracite, and bituminous coal as a raw material in the production of activated carbons. Coal is the most popular precursor owing to its cost-effectiveness and to better mechanical properties of the adsorbents obtained from coal compared to those produced with the use of lignocellulosic materials [12,13]. Interesting research results have been presented in a paper by Carrasco-Marin et al [14], where bituminous coal from Puertollano (Spain) demineralized with HC1 and HF was used to prepare microporous activated carbons.…”