Adsorptive removal of orange G dye from aqueous solution by ultrasonic-activated peanut shell powder: isotherm, kinetic and thermodynamic studies

ABSTRACT

The current study is to develop surface-modified peanut shell granules by incorporating activated carbon to enhance the removal efficiency of Orange G dye (OGD) through adsorption. Activated carbon was prepared from Arachis hypogaea shell (Peanut shell) using a chemical activation method. Ultrasonic Activated Peanut Shell Powder (UAPSP) was characterised using FT-IR and SEM analysis to identify functional groups and assess surface morphology. To determine the optimal conditions, a batch adsorption study was conducted. The results indicated a maximum removal efficiency of 99.5% and a maximum adsorption capacity of 298.36 mg/g under the following parameters: pH 5, temperature 303 K, interaction period of 60 min, a dosage of 0.5 g/L for an OGD concentration of 10 mg/L. The adsorption mechanism in the current system was evaluated using the Langmuir, Freundlich, Sips, Temkin, and D-R isotherms models. Among these, the Langmuir isotherm exhibited the best fit with an R² value of 0.997. UAPSP demonstrated a monolayer adsorption capacity of 1.9 mg/g for OGD removal. The pseudo-second-order kinetic model provided the most effective fit with an R² value of 0.998. Thermodynamic studies revealed that the adsorption process was spontaneous and exothermic, as evidenced by the negative values of ΔG° ( −1.497) and ΔS° (16.4052) at 303 K. Additionally, the mean free energy value (E) in the D-R isotherm increased to 10.58 KJ/mol with a temperature rise from 303 K to 343 K. The characterisation results confirmed that UAPSP is an effective, cost-free, and commercial alternative adsorbent for the removal of hazardous dyes from wastewater.

GRAPHICAL ABSTRACT

KEYWORDS:

• Adsorption
• ultrasonic activated peanut shell powder
• kinetics
• isotherms
• thermodynamics

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available with in the article [and/or] its supplementary materials. Corresponding author will provide data on a reasonable request.