Aqueous phase adsorption of different sized molecules on activated carbon fibers: Effect of textural properties.
The effect that the textural properties of rayon-based activated carbon fibers (ACFs), such as the BET surface area and pore size distribution (PSD), have on the adsorption of differently sized molecules, namely, brilliant yellow (BY), methyl orange (MO) and phenol (PH), was investigated in the aqueous phase. ACF samples with different BET areas and PSDs were produced by steam-activating carbonized fibers for different activation times (0.25, 0.5, and 1 h). The samples activated for 0.25 h were predominantly microporous, whereas those activated for relatively longer times contained hierarchical micro-mesopores. The adsorption capacities of the ACFs for the adsorbate increased with increasing BET surface area and pore volume, and ranged from 51 to 1306 mg/g depending on the textural properties of the ACFs and adsorbate size. The adsorption capacities of the hierarchical ACF samples followed the order BY > MO > PH. Interestingly, the number of molecules adsorbed by the ACFs followed the reverse order: PH > MO > BY. This anomaly was attributed to the increasing molecular weight of the PH, MO and BY molecules. The equilibrium adsorption data were described using the Langmuir isotherm. This study shows that suitable textural modifications to ACFs are required for the efficient aqueous phase removal of an adsorbate.
Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India.
Yogendra N
YN
Prajapati
Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India.
Bhaskar
B
Bhaduri
Defense Materials and Stores Research & Development Establishment, Kanpur 208013, India.
Harish C
HC
Joshi
Defense Materials and Stores Research & Development Establishment, Kanpur 208013, India.
Anurag
A
Srivastava
Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India; Center for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India. Electronic address: vermanishith@gmail.com.
Nishith
N
Verma
D000327:Adsorption; D001391:Azo Compounds / Q000737:chemistry*; D001557:Benzenesulfonates / Q000737:chemistry*; D002244:Carbon / Q000032:analysis*; D000077482:Carbon Fiber; D002482:Cellulose / Q000032:analysis; D002606:Charcoal / Q000032:analysis; D004396:Coloring Agents / Q000737:chemistry; D019800:Phenol / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
D001391:Azo Compounds; D001557:Benzenesulfonates; D000077482:Carbon Fiber; D004396:Coloring Agents; D014874:Water Pollutants, Chemical; D002606:Charcoal; D019800:Phenol; C100258:methyl orange; D002244:Carbon; D002482:Cellulose; C059622:Direct Yellow 4 dye; C012024:rayon, purified
Activated carbon fiber; Adsorbate size; Adsorption; BET surface area; Pore size distribution