Anis Atikah Ahmad
Thumbnail Image
Preferred name
Anis Atikah Ahmad
Official Name
Anis Atikah, Ahmad
Alternative Name
Ahmad, Anis Atikah
Ahmad, Anis A.
Main Affiliation
Scopus Author ID
56900415200
Researcher ID
P-6794-2018

Research Output

Filters

2 1
2
2
Reset filters

Settings
Now showing 1 - 2 of 2
No Thumbnail Available
Publication

Effective removal of methylene blue from aqueous solution by adsorption onto gasification char: isotherm, kinetic and thermodynamics studies

2023 , Nurul Najihah Ahmad , Anis Atikah Ahmad , Azduwin Khasri

This study presents the preparation of oil palm empty fruit bunch (OPEFB) activated char from gas-ification plant residues via phosphoric acid chemical treatment for adsorption of methylene blue (MB) in aqueous solution. The Fourier-transform infrared (FTIR), scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) analysis were conducted to identify the characteristic of OPEFB. Adsorption experiments were carried out to determine the effects of initial dye concentration 100–300 mg/L, contact time, pH 2–10 and temperature 30°C–60°C. The optimum conditions were achieved at adsorbent dosage, pH, initial dye concentration and temperature of 0.2 g/200 mL, 6, 100 mg/L and 60°C, respectively with 91.44% of MB removal. From isotherm study, the Freundlich isotherm model fitted the adsorption data very well owing to its higher value of correlation factor (R2 = 0.9352), compared to Langmuir model (R2 = 0.8682). The Langmuir maximum monolayer capac-ity, qm was estimated at 167.2 mg/g. The results from the kinetic study showed that the MB adsorp-tion followed a pseudo-second-order kinetic model (R2 = 0.9216–0.9581). The adsorption of the MB dye onto OPEFB activated char was an endothermic and spontaneous process with ΔH°, ΔG° and ΔS° values of 58.379 kJ/mol, –0.70505 kJ/mol and 194.955 J/mol‧K, respectively. The obtained results suggest that the OPEFB char could be a promising candidate as an adsorbent for MB removal.

View
No Thumbnail Available
Publication

Gasification char adsorbent for dye removal: characterization, isotherm, kinetics and thermodynamic studies

2025 , Valarmathi Saravanan , Anis Atikah Ahmad , Mohd Azmier Ahmad , Azduwin Khasri

Previous research has shown GC's reliable performance as an adsorbent in water and wastewater treatment, but broader applications remain underexplored. This study focuses on treating GC with KOH to eliminate methylene blue (MB) dye. The FTIR results indicated an enrichment of carbonyl groups on the GC surface, which enhanced the rate of MB adsorption. SEM analysis of both treated and untreated GC revealed that the treated char exhibited prominently developed pores and displayed a distinct open-porous structure, reminiscent of a honeycomb-like porous formation. The result from Brunauer–Emmett–Teller (BET) analysis reveals that BET surface area (469.27 m2/g) and total pore volume (0.2728 cm3/g) of treated GC improved after activation. Increasing the initial concentration of MB from 100 to 250 mg/L resulted in a decrease in its removal from 82.1 to 50.87%, respectively. Meanwhile, raising the pH from 3 to 9 enhanced MB adsorption from 85.46 to 97.06%. As the temperature increased from 30 to 60 Â°C, the adsorption process accelerated, leading to an increase in the percentage of dye removal from 89.11 to 96.63%. Matlab curve fitting tools were used to fit non-linear isotherm and kinetic models. The n-BET isotherm and Pseudo-First-Order (PFO) kinetic models demonstrated an excellent fit to the experimental data, evidenced by the highest R2 values, specifically 0.99206 and 0.9577–0.9855, respectively. These findings strongly suggest a multilayer adsorption process taking place on the uniform surface of treated GC. Thermodynamic analysis affirms the endothermic and spontaneous nature of the adsorption process, corroborated by negative ΔG° and positive ΔH° values ranging from -11.0722 to -8.1916 kJ/mol and from 0.694 to 0.857 kJ/mol, respectively.

View