The Effect of the Modification of Carbon Spheres with ZnCl2 on the Adsorption Properties towards CO2

Abstract

Zinc chloride and potassium oxalate are often applied as activating agents for carbon materials. In this work, we present the preparation of ZnO/carbon spheres composites using resorcinol-formaldehyde resin as a carbon source in a solvothermal reactor heated with microwaves. Zinc chloride as a zinc oxide source and potassium oxalate as an activating agent were applied. The effect of their addition and preparation conditions on the adsorption properties towards carbon dioxide at 0 °C and 25 °C were investigated. Additionally, for all tested sorbents, the CO2 sorption tests at 40 °C, carried out utilizing a thermobalance, confirmed the trend of sorption capacity measured at 0 and 25 °C. Furthermore, the sample activated using potassium oxalate and modified using zinc chloride (a carbon-to-zinc ratio equal to 10:1) displayed not only a high CO2 adsorption capacity (2.69 mmol CO2/g at 40 °C) but also exhibited a stable performance during the consecutive multicycle adsorption–desorption process.

CO2 Sorbents Based on Spherical Carbon and Photoactive Metal Oxides: Insight into Adsorption Capacity, Selectivity and Regenerability

“…For the composites consisting of carbon spheres and zinc oxide, the obtained nitrogen isotherms were a mixture of type I and II, characteristic of micro- and macroporous materials [ 31 ]. In the samples with a low content of carbon spheres, we can observe a hysteresis loop type H3, which disappeared in the samples with a large amount of carbon spheres, from 1 to 4 g. For 1.00 CS/ZnO, 1.60 CS/ZnO, and 4.00 CS/ZnO samples, the nitrogen adsorption isotherms have the shape typical of microporous materials.…”

“…In our previous studies, we investigated the effect of modification of carbon spheres with zinc oxide (obtained from ZnCl 2 or Zn(NO 3 ) 2 ), and activation with potassium oxalate, on their surface parameters and the sorption capacity towards carbon dioxide. The specific surface area of the obtained materials ranged from 381 to 1233 m 2 /g, and the sorption capacity towards CO 2 in the best case reached 2.69 mmol/g (2.18 × 10 −6 mol/m 2 ) at 40 °C [ 30 , 31 ]. For the modification of CS with titanium dioxide, Wang et al [ 32 ] obtained spheres using a template hydrothermal method, which resulted in materials with a specific surface area of 386 m 2 /g, with 4.5 times higher photocatalytic activity than pure TiO 2 (Degussa P25).…”

CO2 Capture from Flue Gas on a Pilot Scale Using Porous Carbon Prepared from Cotton Stalk Crop Residues through an Industrially Viable Activation Process

“…Compared with physical activation techniques, chemical activation has the potential to produce PC of superior quality. For the chemical activation of agro-residues, several chemicals have been used, including NaOH, KOH, − ZnCl 2, H 3 PO 4, K 2 CO 3, K 2 S 2 O 3, CaCO 3, and Na 2 CO 3. Due to its ability to produce clearly defined pores and obtain high surface areas, KOH is the preferred reagent. ,,, However, for the production of biomass to carbon at a scale, its extensive utilization is frequently economically unviable.…”

CO2 Adsorption Study of Potassium-Based Activation of Carbon Spheres

“…The increased porosity and structural defects of the end-product are also good predictors of final reactivity. Carbon or carbonized materials can be activated via chemical or/and physical processes [ 16 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. Additionally, to further improve the performance of certain carbon materials, and find an optimal path for their preparation, a combination of both pathways (chemical and physical) can be used [ 34 , 35 ].…”

“…Chemical activation involves impregnating raw materials with certain chemical agents and then thermally decomposing them in a single step, which allows for an increased BET surface area [ 17 ]. Activated carbon spheres can be obtained by mixing the carbon spheres with a chemical agent, such as ZnCl 2 [ 27 ], H 3 PO 4 [ 28 ], KOH [ 29 ], K 2 CO 3 [ 30 ], K 2 C 2 O 4 [ 31 , 32 ], NaOH [ 33 ]. These substances act both as dehydrating agents and as oxidants, ensuring that carbonization and activation can take place simultaneously.…”