Cationic dye remediation in water treatment with Lizardite–Rice Husk composite: A statistical physics approach

• Published in: Journal of molecular liquids 2024-11, Vol.414, p.126096, Article 126096
• Main Authors: Allahkarami, Esmaeil, Allahkarami, Ebrahim, Heydari, Majid, Azadmehr, Amirreza, Maghsoudi, Abbas
• Format: Article
• Language: English
• Subjects: Adsorption; Cationic dyes; Lizardite; Rice Husk; Statistical physics modeling
• ISSN: 0167-7322
• DOI: 10.1016/j.molliq.2024.126096

•Lizardite-Rice Husk Composite removes Methylene Blue and Malachite Green.•Statistical physics modeling was used to explore the mechanism of dye adsorption.•Monolayer adsorption model effectively describes Methylene Blue removal.•Adsorption energy was smaller than 80 kJ/mol, indicating physical interactions.•ANN and CCD exhibit high predictive accuracy for Methylene Blue adsorption. This study presents the development of a novel composite adsorbent, Lizardite-Rice Husk Composite (LRHC), synthesized from lizardite, a mineral derived from chromite ore waste, and rice husk, an agricultural byproduct. The primary objective was to evaluate the efficiency of LRHC in the adsorption of cationic dyes, Malachite Green (MG) and Methylene Blue (MB), from aqueous solutions. Systematic investigations were conducted to assess the influence of adsorbent mass, initial dye concentration, stirring speed, and contact time on adsorption performance. The results revealed that LRHC exhibited optimal adsorption capacities at pH values above 5, with MB and MG adsorption capacities reaching 309.75 mg/g and 51.43 mg/g, respectively. Adsorption equilibrium for MB was achieved within 30 min, indicating rapid dye uptake. Isotherm analysis demonstrated that the Temkin model best described MB adsorption, while the Freundlich model was more suitable for MG, with favorable Langmuir constants. Kinetic studies confirmed that the adsorption followed a second-order model, suggesting chemisorption as the rate-determining step. Intraparticle diffusion and mass transfer were identified as significant contributors to the adsorption process. Thermodynamic studies indicated that MB adsorption was spontaneous (ΔG° = −4.69 kJ/mol for the concentration of 50 mg/L at 298 K) and that MG adsorption was non-spontaneous (ΔG° = 1.52 kJ/mol for the concentration of 50 mg/L at 298 K), with spontaneity increasing at higher initial concentrations. Statistical physics modeling, particularly the monolayer model, provided detailed insights into the adsorption mechanisms and geometry. Furthermore, LRHC demonstrated excellent reusability, maintaining over 80% of its initial adsorption capacity after four regeneration cycles via a heterogeneous Fenton-like reaction. The combination of easy availability, cost-effectiveness, and environmental friendliness makes LRHC a superior adsorbent for the removal of cationic dyes compared to conventional alternatives. This research contributes novel insights into the design and ap