Recycling of Walnut Shell Biomass for Adsorptive Removal of Hazardous Dye Alizarin Red from Aqueous Solutions Using Magnetic Nanocomposite: Process Optimization, Kinetic, Isotherm, and Thermodynamic Investigation

Dye wastewater poses significant risks to human health and aquatic ecosystems, necessitating efficient remediation strategies. This study developed a magnetic Fe<sub>2</sub>O<sub>3</sub> nanocomposite (MNC) derived from phosphoric acid-treated walnut shell biomass carbon to r...

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Main Authors: Vairavel Parimelazhagan, Palak Sharma, Yashaswini Tiwari, Alagarsamy Santhana Krishna Kumar, Ganeshraja Ayyakannu Sundaram
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:ChemEngineering
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Online Access:https://www.mdpi.com/2305-7084/9/2/40
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author Vairavel Parimelazhagan
Palak Sharma
Yashaswini Tiwari
Alagarsamy Santhana Krishna Kumar
Ganeshraja Ayyakannu Sundaram
author_facet Vairavel Parimelazhagan
Palak Sharma
Yashaswini Tiwari
Alagarsamy Santhana Krishna Kumar
Ganeshraja Ayyakannu Sundaram
author_sort Vairavel Parimelazhagan
collection DOAJ
description Dye wastewater poses significant risks to human health and aquatic ecosystems, necessitating efficient remediation strategies. This study developed a magnetic Fe<sub>2</sub>O<sub>3</sub> nanocomposite (MNC) derived from phosphoric acid-treated walnut shell biomass carbon to remove Alizarin red S (AR) dye from polluted water. Characterization techniques confirmed the nanocomposite’s mesoporous structure, superparamagnetic properties (61.5 emu/g), and high crystallinity. Optimization using Response Surface Methodology (RSM) revealed a maximum adsorption efficiency of 94.04% under the following optimal conditions: A pH of 2, AR dye concentration of 85 mg/L, adsorbent dose of 1.5 g/L, and particle size of 448.1 nm. Adsorption followed pseudo-second-order (PSO) kinetics (R<sup>2</sup> = 0.9999) and Langmuir isotherm models (R<sup>2</sup> = 0.9983), with thermodynamic studies indicating spontaneous and endothermic chemisorption. The intra-particle diffusion model, Bangham, and Boyd plots describe the adsorption process, and external boundary layer diffusion of AR dye molecules in the aqueous phase limits the adsorbate removal rate. Regeneration tests demonstrated reusability over three cycles, with a desorption efficiency of 50.52% using 30 mM HCl. The MNC exhibited a maximum adsorption capacity (Q<sub>max</sub>) of 115.35 mg/g, outperforming other adsorbents, making it an efficient and sustainable alternative solution for AR dye removal from water bodies.
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spelling doaj-art-4399a0f1ff7d4d7a88cd87762fa77c182025-08-20T02:17:19ZengMDPI AGChemEngineering2305-70842025-04-01924010.3390/chemengineering9020040Recycling of Walnut Shell Biomass for Adsorptive Removal of Hazardous Dye Alizarin Red from Aqueous Solutions Using Magnetic Nanocomposite: Process Optimization, Kinetic, Isotherm, and Thermodynamic InvestigationVairavel Parimelazhagan0Palak Sharma1Yashaswini Tiwari2Alagarsamy Santhana Krishna Kumar3Ganeshraja Ayyakannu Sundaram4Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education (MAHE), Manipal 576 104, Karnataka, IndiaDepartment of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education (MAHE), Manipal 576 104, Karnataka, IndiaDepartment of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education (MAHE), Manipal 576 104, Karnataka, IndiaDepartment of Chemistry, National Sun Yat-sen University, No. 70, Lienhai Road, Gushan District, Kaohsiung 80424, TaiwanDepartment of Research Analytics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai 600 077, Tamil Nadu, IndiaDye wastewater poses significant risks to human health and aquatic ecosystems, necessitating efficient remediation strategies. This study developed a magnetic Fe<sub>2</sub>O<sub>3</sub> nanocomposite (MNC) derived from phosphoric acid-treated walnut shell biomass carbon to remove Alizarin red S (AR) dye from polluted water. Characterization techniques confirmed the nanocomposite’s mesoporous structure, superparamagnetic properties (61.5 emu/g), and high crystallinity. Optimization using Response Surface Methodology (RSM) revealed a maximum adsorption efficiency of 94.04% under the following optimal conditions: A pH of 2, AR dye concentration of 85 mg/L, adsorbent dose of 1.5 g/L, and particle size of 448.1 nm. Adsorption followed pseudo-second-order (PSO) kinetics (R<sup>2</sup> = 0.9999) and Langmuir isotherm models (R<sup>2</sup> = 0.9983), with thermodynamic studies indicating spontaneous and endothermic chemisorption. The intra-particle diffusion model, Bangham, and Boyd plots describe the adsorption process, and external boundary layer diffusion of AR dye molecules in the aqueous phase limits the adsorbate removal rate. Regeneration tests demonstrated reusability over three cycles, with a desorption efficiency of 50.52% using 30 mM HCl. The MNC exhibited a maximum adsorption capacity (Q<sub>max</sub>) of 115.35 mg/g, outperforming other adsorbents, making it an efficient and sustainable alternative solution for AR dye removal from water bodies.https://www.mdpi.com/2305-7084/9/2/40Alizarin red dyewalnut shell carbon-Fe<sub>2</sub>O<sub>3</sub> nanocompositeresponse surface methodologyadsorption kineticsequilibrium isothermsthermodynamics
spellingShingle Vairavel Parimelazhagan
Palak Sharma
Yashaswini Tiwari
Alagarsamy Santhana Krishna Kumar
Ganeshraja Ayyakannu Sundaram
Recycling of Walnut Shell Biomass for Adsorptive Removal of Hazardous Dye Alizarin Red from Aqueous Solutions Using Magnetic Nanocomposite: Process Optimization, Kinetic, Isotherm, and Thermodynamic Investigation
ChemEngineering
Alizarin red dye
walnut shell carbon-Fe<sub>2</sub>O<sub>3</sub> nanocomposite
response surface methodology
adsorption kinetics
equilibrium isotherms
thermodynamics
title Recycling of Walnut Shell Biomass for Adsorptive Removal of Hazardous Dye Alizarin Red from Aqueous Solutions Using Magnetic Nanocomposite: Process Optimization, Kinetic, Isotherm, and Thermodynamic Investigation
title_full Recycling of Walnut Shell Biomass for Adsorptive Removal of Hazardous Dye Alizarin Red from Aqueous Solutions Using Magnetic Nanocomposite: Process Optimization, Kinetic, Isotherm, and Thermodynamic Investigation
title_fullStr Recycling of Walnut Shell Biomass for Adsorptive Removal of Hazardous Dye Alizarin Red from Aqueous Solutions Using Magnetic Nanocomposite: Process Optimization, Kinetic, Isotherm, and Thermodynamic Investigation
title_full_unstemmed Recycling of Walnut Shell Biomass for Adsorptive Removal of Hazardous Dye Alizarin Red from Aqueous Solutions Using Magnetic Nanocomposite: Process Optimization, Kinetic, Isotherm, and Thermodynamic Investigation
title_short Recycling of Walnut Shell Biomass for Adsorptive Removal of Hazardous Dye Alizarin Red from Aqueous Solutions Using Magnetic Nanocomposite: Process Optimization, Kinetic, Isotherm, and Thermodynamic Investigation
title_sort recycling of walnut shell biomass for adsorptive removal of hazardous dye alizarin red from aqueous solutions using magnetic nanocomposite process optimization kinetic isotherm and thermodynamic investigation
topic Alizarin red dye
walnut shell carbon-Fe<sub>2</sub>O<sub>3</sub> nanocomposite
response surface methodology
adsorption kinetics
equilibrium isotherms
thermodynamics
url https://www.mdpi.com/2305-7084/9/2/40
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