Rozaini Abdullah
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Preferred name
Rozaini Abdullah
Official Name
Rozaini, Abdullah
Alternative Name
Abdullah, Rozaini
Abdullah, R.
Main Affiliation
Scopus Author ID
25721634700
Researcher ID
EJS-8999-2022

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  • Publication
    Kinetic and Isotherm Studies of Malachite Green Adsorption From Aqueous Solution by Calcined Eggshell Treated Orange Peel
    ( 2023-06-09)
    Chun H.K.
    ;
    Sharifah Zati Hanani Syed Zuber
    ;
    Nor Fauziah Zainudin
    ;
    Noor Amirah Abdul Halim
    ;
    Rozaini Abdullah
    ;
    Mohd Qalani Che Kasim
    In this work, the ability of eggshell treated orange peel as a low-cost adsorbent to remove malachite green (MG) dye from an aqueous solution was investigated. The eggshell treated orange peel was characterized by using Fourier transform infrared (FTIR) spectroscopy analysis. From the FTIR analysis, the functional group that might be involved in the adsorption process was found to be carboxylic acid and alcohol. The effect of contact time, initial dye concentration and adsorbent dosage were also investigated by using batch adsorption mode. The results showed that the percentage of dye removal increased with the increase of contact time and the process attained equilibrium within 140 minutes with the highest percentage of MG dye removal was 98%. The percentage of dye removal was also found to increase with the increase of initial dye concentration and adsorbent dosage. The experimental result showed that 0.1 g eggshell treated orange peel was able to remove 98% of MG dye while about 99% of MG dye was removed for 250 mg/L of dye concentration. The adsorption isotherm data were well fitted to the Langmuir isotherm model with the qmax of 31.45 mg g-1. Meanwhile, the kinetic data was best presented by the pseudo-second-order model with R2> 0.99.
      31  1
  • Publication
    Parameter effects and optimisation studies on ultrasound-assisted extraction of polyphenolics from mango peel wastes
    (AIP Publishing, 2024-04)
    Noor Amirah Abdul Halim
    ;
    Mohammed Abdullah Issa
    ;
    Wan Jing Ooi
    ;
    Sharifah Zati Hanani Syed Zuber
    ;
    Nor Fauziah Zainudin
    ;
    Rozaini Abdullah
    In this study, the bioactive properties, such as the total phenolic content (TPC), total flavonoid compound (TFC), and the antioxidant activity of mango peel wastes (MPW) extract were evaluated. The extract was obtained through an ultrasound-assisted extraction (UAE) technique, where 70% ethanol was used as the extractive medium. The main effects of extraction parameters involving the solvent-to-sample ratio, sonication time, and extraction time were studied through a single-factor experiment. It was found that the highest TPC, TFC, and antioxidant activity can be obtained at conditions of 40 mL/g, 30 min, and 50 °C, respectively. Based on the conditions, the TPC was optimised by response surface methodology (RSM), where a significant quadratic regression model with R2 of 0.92 was acquired. The optimum conditions were obtained at 41.49:1 solvent-to-sample ratio, 31.15 min sonication time, and 46.87 °C extraction temperature with a maximum TPC of 25.58 mg GAE/g. Validation experiments were conducted at the optimum extraction condition and successfully yielded a higher TPC yield with an average value of 26.11±2.11 mg GAE/g.