Preparation and evaluation of Fuller's Earth Beads for removal of Cesium from waste streams

This work deals with removal of Cesium (radioactive waste) in dilute aqueous phase by adsorption. Fullers earth was used as an adsorbent. The adsorption capacity of Fullers earth with respect to Cesium was found to be high, 26.3 mg / g of adsorbent.

A geotechnical description of fresh cement grout - filtration and consolidation behaviour

The removal of water from three Portland cement grouts by pressure filtration is examined, and the consolidation behaviour of the filtered material clarified. The filtration takes place by the laying down of a very stiff filter cake through the removal of excess water. The behaviour due to further loading resembles that of a re-constituted silt. For stress levels above the filtration pressure the calculated permeability values are similar to those from the filtration phase only if the data sampling rate was sufficiently rapid to discriminate the first portion of the observed primary consolidation curve. The change in void ratio for incremental loading is roughly linear with the change in the logarithm of the vertical effective stress. The characterisation of fresh cement paste using standard soil mechanics models is both appropriate and useful, at least during the first few hours after mixing.

Sorption behavior of cationic and anionic dyes from aqueous solution on different types of activated carbons

The effect of dye molecular charges on their adsorption from solution was investigated by using different types of activated carbon adsorbents. Two types of model systems were used representing cationic and anionic dyes. Screening investigations using single point tests were used throughout the study. Cationic dyes, of which Methylene Blue is an example, showed a higher adsorption tendency towards activated carbon over anionic dyes represented by an ate-type reactive compound. Of the number of activated carbons tested, only one of the adsorbents showed an exception to this behavior, and a good relation was observed between Methylene Blue capacity and activated carbon performance. The high capacity of cationic dyes in comparison to anionic dyes was also evident in the results obtained by a preliminary kinetic study carried out on the selected systems. Surface net charge of activated carbon and the nature of attractions between the molecules were suggested to be one of the reasons attributed for this behavior.

Separation of acid-dyes mixture by bamboo derived active carbon

In the present study, the activated carbon is produced using phosphoric acid treatment of the waste bamboo scaffolding and activated at either 400 or 600 °C. The effect of acid to bamboo ratio (Xp) up to 2.4 has been studied. The BET surface area increased with increasing Xp and activating temperature. BET surface area up to 2500 m2/g carbon has been produced. In order to simulate effluent treatment from textile industry, the produced carbon was tested for its dye adsorption capacities. Two acid dyes with different molecular sizes were used, namely Acid Yellow 117 (AY117) and Acid Blue 25 (AB25). In a single component system, it was found that dye with smaller molecular size, AB25, was readily adsorbed onto the carbon while the larger size dye, AY117, showed little adsorption. As a result, it is possible to tailor-make the carbon for the adsorption of dye mixtures in industrial applications, especially textile dyeing, i.e. molecular sieve effect. A binary AY117–AB25 mixture was used to test the possibility of the molecular sieve effect. Furthermore, experimental results were fitted to equilibrium isotherm models, Langmuir, Freundlich and Sips for the single component system. For the binary component system, extended single-component equilibrium isotherm models were used to predict the experimental data.