Exploring the utilisation of natural bio-sorbents for effective methylene blue removal
Publication Date
January 8, 2024
Creators
Description
This paper presents a comprehensive analysis of adsorbent capacity of five distinctly different bio-sorbents derived from untreated biomasses. The optimal adsorption capacity of seaweed (Laminaria digitata), horse chestnut husk, hazelnut husk, rapeseed residue, and whitewood) to re-move methylene blue (MB) dye was assessed by analysing the effects of particle size, pH, temperature, and initial dye concentrations. Furthermore, the adsorption kinetics, isotherms, and adsorption thermodynamics were investigated. The results showed that relatively high MB ad-sorption capacity was achieved by Laminaria digitata (~180 mg/g), in addition to a reasonable MB adsorption capacity of horse chestnut husk (~130 mg/g), hazelnut husk (~110 mg/g), and rapeseed residue (~80 mg/g). However, whitewood provides a relatively low adsorption capacity of below 20 mg/g. The best fit with experimental results regardless of bio-sorbent type was a Pseudo-second-order kinetic model with lowest the mean absolute percentage error (ε, MAPE < 2.5%) and the highest correlation coefficients (R2 > 0.99). Although the pseudo-second-order kinetic model is often associated with chemisorption, the low enthalpy values (<29.30 kJ/mol) typically suggest that the adsorption process is more characteristic of physisorption, which involves weaker van der Waals forces rather than the stronger covalent bonds of chemisorption. This proposed a multi-step adsorption process involving both physisorption and chemisorption. The adsorption isotherm of Langmuir showed superior fitting results for Laminaria digitata and hazelnut husk. In contrast, rapeseed residue and horse chestnut husk fitted better with the Freundlich adsorption isotherm. The Langmuir adsorption isotherms showed a maximum adsorption capacity of ~500 mg/g for Laminaria digitata, followed by horse chestnut husk (~137 mg/g), hazelnut husk (~120 mg/g), and rapeseed residue (~85 mg/g). The Gibbs free energy was negative for Laminaria digitata < horse chestnut husk < hazelnut husk < 0, which suggests that the removal of MB is thermodynamically favourable, as the adsorption process occurs spontaneously. The results of the study indicate that MB dye removal using untreated biomasses has the potential to be a low-cost valorisation option in the holistic whole life cycle valorisation pathway for Laminaria digitata, horse chestnut husk, and hazelnut husk.
Collection dates: August 2020-August 2021
Collection dates: August 2020-August 2021
Subjects (LCSH)
Subjects
Subjects (JACS)
Subjects (LC)
Divisions
University of Nottingham, UK Campus::Faculty of Engineering::Department of Chemical and Environmental Engineering
Data type
Excel data
Funders
University of Nottingham Anne McLaren Research Fellowship
Grant Number
EP/S000771/1
BB/S010610/1
Data collection method
instruments: mill, sieves, elemental anyalser, FTIR, TGA, BET, incubator, UV-Vis
Resource languages
English
Publisher
The University of Nottingham
Date Issued
January 8, 2024
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Name
MB Adsorption over biosorbents_FG.xlsx
Description
Experimental Data
Size
132.55 KB
Format
Microsoft Excel XML
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