Fly ash: An alternative to powdered activated carbon for the removal of eosin dye from aqueous solutions

Abstract

ABSTRACT. This paper reports the use of powdered activated carbon (PAC) and raw coal fly ash (RFA) in the removal of eosin dye from aqueous solution in batch processes. Operational parameters such as contact time, initial dye concentration, pH and temperature were investigated. Adsorption equilibrium was established in 120 min for the two adsorbents. Langmuir and Freundlich isotherms were used to fit the adsorption data. Langmuir model gave the best fit in both cases. The adsorption capacities of PAC and RFA were found to be 62.28 mg/g and 43.48 mg/g, respectively. The highest percentage of eosin dye removal for both PAC (98%) and RFA (90%) was observed at pH 2. Pseudo first-order and pseudo second-order kinetic models were used to fit the adsorption data. Pseudo second-order kinetic model gave the best description of the adsorption of eosin dye onto the two adsorbents. Thermodynamic parameters, ∆H 0 , ∆S 0 and ∆G 0 confirmed the physical nature, spontaneity and the endothermic nature of the adsorption process. A regeneration technique and a process calculation for evaluating the adsorbent dose required were carried out. This study has shown that RFA is a good alternative adsorbent in the removal of eosin dye from aqueous solution.

Biosorption of an Anionic Dye, Eosin Yellow onto Pineapple Peels: Isotherm and Thermodynamic Study

“…The obtained value of the separation factor (RL) was 0.04 (Table 1) which fall in the range 0 < RL < 1, an indication of the favorability of the adsorption process and high degree of irreversibility. Similar results were also reported by [3], [8], [10], [23]. Table 3 lists some maximum adsorption capacities of various dyes onto pineapple peels (PP).…”

“…The values of RL indicates the type of isotherm for an irreversible adsorption process (RL = 0), favorable adsorption (0 < RL < 1), linear adsorption (RL =1) or unfavorable adsorption process (RL > 1) [8], [10], [20]. Temkin isotherm model assumes that heat of adsorption (function of temperature) of all molecules in the layer would decrease linearly rather than logarithmic with coverage [21].…”

“…Only a few researchers have carried out investigations into the adsorption of Eosin yellow from aqueous systems using different adsorbents such as modified sawdust [8], conditioned chitosan hydrobeads [7], activated carbon [1], Teak Leaf Litter Powder [5] and EDTA modified chitosan [9]. Activated carbon is the most commonly used adsorbent, which is capable of adsorbing most dyes with high adsorption efficiency [10]. It is however, economically expensive and has a high cost of regeneration due to difficulty in desorption of the already adsorbed dye molecules [10], [11].…”

“…Activated carbon is the most commonly used adsorbent, which is capable of adsorbing most dyes with high adsorption efficiency [10]. It is however, economically expensive and has a high cost of regeneration due to difficulty in desorption of the already adsorbed dye molecules [10], [11]. Various low-cost adsorbents that can compete favorably with Commercial activated carbon have been investigated as alternative adsorbents [11].…”

Removal of imidacloprid using activated carbon produced from ricinodendron heudelotii shells

“…To resolve these issues, adsorption has been widely investigated as one of the most prominent methods to remove such waste. The main material frequently employed in this technique is activated carbon which has the advantage to possess large surface area, excellent internal and external functions, large adsorption capacities and good adsorption kinetics [13][14][15][16]. The most commonly used precursors are agricultural wastes particularly coconut shell, rice bran, seed hull of the palm tree and olive stones [14,16,17].…”