The importance of being porous: polysaccharide-derived mesoporous materials for use in dye adsorption

Abstract

The controlled pyrolysis of mesoporous polysaccharide-derived materials, from starch and alginic acid, formed carbonaceous materials (Starbons 1 ) and were demonstrated as efficient materials for the removal of dyes from wastewater. The resulting materials were characterised by solid-state NMR, N 2 adsorption porosimetry, FT-IR, scanning electron microscopy (SEM) and tunnelling electron microscopy (TEM). The material's efficiency for dye adsorption was tested using methylene blue (MB) and acid blue 92 (AB) dyes. Adsorption data indicated that the mesoporosity of the material had a far greater influence on the adsorption capacity and speed of adsorption, than high surface area alone. Mesoporous Starbon 1 (A300) was evaluated against commercially available activated carbon (Norit) and demonstrated a superior adsorption capacity of MB; 186 mg g 21 vs. 42 mg g 21 . The kinetic activity of Starbon 1 was also determined with A800 showing the fastest rate of adsorption compared to S800 and Norit, suggesting that it is a more suitable material for water purification.

Treatment of laundrette wastewater using Starbon and Fenton's reagent

“…The resulting material is referred to as S300. Full characterisation of S300 can be found in the work of Parker et al [12] Fenton's reagent Fenton's reagent, which is a solution of Fe 3C (prepared from ferric chloride) and hydrogen peroxide (30%, by weight), was used in the experiments for hydroxyl radical generation. Sulphuric acid and sodium hydroxide were used to adjust the pH to the desired values.…”

“…Previous work carried out by Parker et al investigating adsorption of dye molecules by Starbon and activated carbon has shown that this mesoporosity increases adsorption rate and capacity compared to the activated carbon Norit Ò . [12] Based on these results, Starbon is considered appropriate as a potential material for laundry grey water treatment.…”

“…[11] Unfortunately, activated carbon also presents disadvantages, i.e., it is highly microporous and these small pores create limited diffusion by slowing pollutant uptake and reducing material efficiency. [12] This led many workers to search for better adsorbent alternatives. [9] biodegradable; they also possess a range of surface functionalities that are maintained in the final Starbon material.…”

“…[9] biodegradable; they also possess a range of surface functionalities that are maintained in the final Starbon material. [12][13][14] Starbon offers the significant advantage, over activated carbon, of being highly mesoporous. Previous work carried out by Parker et al investigating adsorption of dye molecules by Starbon and activated carbon has shown that this mesoporosity increases adsorption rate and capacity compared to the activated carbon Norit Ò .…”

Investigating the structure of biomass-derived non-graphitizing mesoporous carbons by electron energy loss spectroscopy in the transmission electron microscope and X-ray photoelectron spectroscopy

“…These samples represent respectively materials prepared using the same pyrolysis temperature as White et al [11] and the pyrolysis temperature more recently favoured for the preparation of Starbon ® material [14].…”