Adsorption Properties of Activated Carbons Prepared from Waste CDs and DVDs

Abstract

Two sets of activated carbons have been prepared from waste CDs and DVDs by carbonization and subsequent activation with either KOH or CO 2 . The resulting activated carbons had specific surface area in the range of 500− 2240 m 2 g −1 , total pore volume in the range of 0.18−1.36 cm 3 g −1 , volume of micropores and small mesopores (w < ∼2.9 nm) in the range of 0.17−1.25 cm 3 g −1 , and volume of small micropores (w < ∼1.2 nm) in the range of 0.14−0.71 cm 3 g −1 . Both KOH and CO 2 activation resulted in 5−45-fold improvement in the structural properties, depending on the conditions used. The resulting carbons showed good adsorption properties toward carbon dioxide, hydrogen, and benzene. The best uptakes for these adsorptives were 5.8 mmol g −1 of CO 2 at 0°C and 800 mmHg, 3.3 mmol g −1 of CO 2 at 25°C and 850 mmHg, 13.9 mmol g −1 of H 2 at −196°C and 850 mmHg, and 15.4 mmol g −1 of C 6 H 6 at 20°C and saturation pressure. The excellent adsorption properties of the prepared carbons render them as potential adsorbents in CO 2 capture and storage, VOCs adsorption/separation, and hydrogen storage.

Agar‐Derived Nitrogen‐Doped Porous Carbon for CO2 Adsorption

“…The CO 2 uptake of Agar-0.5-600-1 at 298 K (3.7 mmol g À 1 ) is lower than some of the reported results, however the uptake of 6.5 mmol g À 1 at 273 K is still very competitive when compared with other carbon materials. For instance, nitrogen doped C-KOH-4 prepared from wasted CDs and DVDs by Jaroniec et al showed a high S BET of 2240 m 2 g À 1 , but the CO 2 uptake at 273 K was 5.8 mmol g À 1 , the lower uptake could be attributed to the generation of abundant mesopores under harsh activation conditions; [19] carbon material KBM-700 with MOF as the carbon and nitrogen source had a high nitrogen content of 10.16 wt %, the low CO 2 uptake of 4.75 mmol g À 1 was due to the fact that the microporosity in KBM-700 was greatly contributed by micropores larger than 1 nm. [6a] The adsorption isotherms of Agar-0.5-550-1 and Agar-0.5-600-1 are very close, but an obvious deterioration of CO 2 uptake is witnessed when the activation temperature reaches 650 or 700°C.…”

Chemical Structure of Phenols and Its Consequence for Sorption Processes

“…-Synthesis of a new sorbent using compounds with polar moieties. In this way, silica-based materials: RP-cyano, RP-hydroxyl, RP-amine [43], polar polymers [2,21,[25][26][27][28] and chemically activated or porous carbons [21,[27][28][29]39] can be produced.…”

Significantly increasing porosity of mesoporous carbon by NaNH2 activation for enhanced CO2 adsorption

“…To create abundant micropores, pristine carbons are usually subjected to post-synthesis activation. KOH [15][16][17][18] is the most frequently used activation agent, while K 2 CO 3 [19], H 3 PO 4 [20], ZnCl 2 [21], NH 3 [22,23], CO 2 [24,25], and H 2 O [26,27] have been less frequently employed. Jaroniec et al [28] compared the ability of different agents for the activation of a commercial carbon and found KOH-activated carbon had the most developed microporosity and enhanced adsorption capacity for CO 2 .…”