Adsorption removal of Methylene Blue (MB) dye from aqueous solution by bio-char prepared from Eucalyptus sheathiana bark: kinetic, equilibrium, mechanism, thermodynamic and process design

Abstract

A B S T R A C TEucalyptus bark (EB) materials-based bio-char adsorbent was synthesised and characterised using SEM-EDS, BET and CHN analyser. The adsorbent surface functional groups were determined by FT-IR analyser. Various textural characteristics such as BET surface area, pore size, bulk density, point of zero charge were also determined. The adsorption potential of these bio-char for the removal of cationic dye Methylene Blue (MB) from aqueous solution was studied. The effects of various temperature profiles on the production of EB biochar were studied and the most efficient temperature profile was identified at 500˚C. Batch adsorption kinetic study showed that the amount of dye adsorbed q t (mg/g) depends on various physicochemical process parameters such as initial solution pH, dye concentration, temperature, adsorbent dose, salt concentration and presence of SDS surfactant. It was found that the extent of MB dye adsorption by EB bio-char increased with the increase of initial dye concentration, contact time, temperature, SDS surfactant concentration and solution pH, but decreased with the increase of adsorbent dose and salt concentration. The optimum adsorption conditions were found at the initial dye concentration of 100 mg/L, initial solution pH of 11.3, adsorbent dose of 10 mg and solution temperature of 55˚C. Furthermore, pseudo-first-order, pseudo-second-order and intra-particle diffusion models were fitted to examine the adsorption kinetics and mechanism of adsorption. Equilibrium data were best represented by Langmuir isotherm model and gives a monolayer effective adsorption capacity of bio-char which is comparative to other adsorbents including commercial activated carbon. Thermodynamic parameters suggested that the adsorption was an endothermic, spontaneous and physical in nature. Furthermore, a single-stage batch adsorber design for the MB dye onto EB bio-char particles were presented based on the Langmuir isotherm model equation. These results indicated EB biomass as good and cheap precursor for the production of an effective and environmental friendly bio-char adsorbent.

Synthesis and characterization of magnetic manganese ferrites

“…MB removal observed within the reactors was greater than 90% within one hour. The magnetic MnFe 2 O 4 PVA15 catalyst showed better reactivity within 1 h of reaction as compared with previous reports on the removal of MB dye [ 22 – 24 ].…”

Syringa vulgaris leaves powder a novel low-cost adsorbent for methylene blue removal: isotherms, kinetics, thermodynamic and optimization by Taguchi method

“…This fact increases dye molecules diffusion rate in the external boundary layer and internal pores of the adsorbent 4 , 22 . The positive effect of temperature on the adsorption capacity was reported for acid treated kenaf fibre char 4 , graphene 8 , phoenix tree's leaves 20 , lotus leaf 21 , Platanus orientalis leaf powder 23 and eucalyptus barks bio-char 53 .…”

“…At the same time, the removal percentage of the dye has decreased from about 84.4 to 75.2%, with an increase in the initial dye concentration. This behavior can be explained by the saturation of the adsorption sites caused by the dye molecules accumulation on the surface of the adsorbent particle 52 , 53 . These observations regarding the influence of the initial dye concentration onto the adsorption capacity and the removal efficiency are in agreement with the results obtained with other adsorbent materials, such as Salix babylonica leaves powder 2 , acid treated kenaf fibre char 4 , eucalyptus barks bio-char 53 .…”

Synthesis and characterization of slow pyrolysis pine cone bio-char in the removal of organic and inorganic pollutants from aqueous solution by adsorption: Kinetic, equilibrium, mechanism and thermodynamic

“…Therefore, researchers are focusing upon the production of cost-effective charcoal and bio-char derived from agriculture solid wastes that can be used for removal of dyes and heavy metals form wastewater. There are many reported agriculture solid waste based char, charcoal , activated carbon and magnetic composite charcoal used in the removal of dyes and heavy metals such as bamboo biochar (Liao et al, 2012), cocoa shell activated carbon (Ribas et al, 2014), pine cone based activated carbon (Dawood et al, 2014), coconut pith char (Johari et al, 2016) , almond shell bio-char (Kılıç et al, 2013), Eucalyptus bark bio-char (Dawood et al, 2016), banana peel bio-char (Zhou et al, 2017), celery bio-char (Zhang et al, 2017), magnetic bamboo charcoal (Nomura et al, 2017) and Korean cabbage bio-char (Sewu et al, 2017). In this research study, pine cone (Pinus radiata) has been selected as a precursor material for the production of cost effective pine cone based bio-char.…”