Electrochemical oxidation of activated carbon fibre – an efficient way of enhancing toxic metal ion sorptive capacity
Advancing the chemical engineering fundamentals
Electrochemical Engineering - I (T2-14a)
Keywords: Viscose rayon based activated carbon cloth; Sorption isotherms; Electrochemical oxidation; Competitive and non-competitive sorption; Characterisation.
There has been increasing concern and more stringent regulation standards pertaining to the discharge of heavy metals to the aquatic environment, due to their toxicity and detriment to living species, including humans. Treatment processes such as chemical precipitation, ultrafiltration, biological processes, electrodialysis, adsorption and reverse osmosis are currently used to remove heavy metal pollutants from water. Granular (GAC) and powder (PAC) activated carbons are used for the removal of heavy metals from aqueous solutions. Due to slow intraparticle diffusion, the rate of sorption in GAC is very slow. The rate of sorption in PAC is very fast, but it presents the disadvantage of complicated handling. Activated carbon fibres exist in the form of cloth (ACC) and felt (ACF). The rate of sorption in ACC is as fast as PAC but it does not present the disadvantage of complicated handling so ACC could be an alternative for the removal of trace heavy metal ions from aqueous solutions. However, sorption capacity of commercially available ACC towards heavy metal removal is low. Consequently, in this work a viscose rayon based ACC was electrochemically oxidised to enhance its cation sorption capacity. The optimum current for electrochemical oxidation of ACC was found to be 1.1 A. The as-received and modified ACCs were characterised in detail. A loss of 49% BET surface area and a significant loss in microporosity were observed on the electrochemically oxidised ACC (EO) and attributed to blockage of pores through formation of carboxylic acidic groups. However, the cation exchange capacity of EO was increased by 365%. Batch sorption experiments confirmed that EO is more effective for the removal of lead and copper ions compared to unoxidised ACC (UO) for both competitive and non-competitive sorption. For EO, the copper and lead sorption capacities increased 17 and 4 times, respectively, for non-competitive sorption and 8.8 and 8.6 times, respectively, for competitive sorption. The results indicated that sorption of lead and copper onto EO was by ion exchange while that onto UO was likely to be due to surface complex formation.
See the full pdf manuscript of the abstract.
Presented Tuesday 18, 11:00 to 11:20, in session Electrochemical Engineering - I (T2-14a).
