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Sorption equilibrium and kinetics of basic dye from aqueous solution using banana stalk waste

Hameed BH, Mahmoud DK, Ahmad AL

J Hazard Mater, 2008 Oct 30;158(2-3):499-506.
PMID: 18353547 DOI: 10.1016/j.jhazmat.2008.01.098

The sorption of basic dye from aqueous solutions by banana stalk waste (BSW), an abundant agricultural waste in Malaysia, was studied in a batch system with respect to pH and initial dye concentration. Sorption isotherm of methylene blue (MB) onto the BSW was determined at 30 degrees C with the initial concentrations of MB in the range of 50-500 mg/L. At pH 2.0, the sorption of dye was not favorable, while the sorption at other pHs (4.0-12.0) was remarkable. Equilibrium data were fitted to the Langmuir, Freundlich and Temkin isotherm models. The equilibrium data were best represented by the Langmuir isotherm model, with maximum monolayer adsorption capacity of 243.90 mg/g. The sorption kinetic data were analyzed using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. It was found that the pseudo-second-order kinetic model was the best applicable model to describe the sorption kinetics. The results showed that BSW sorbent was a promising for the removal of MB from aqueous solutions.
Equilibrium modeling and kinetic studies on the adsorption of basic dye by a low-cost adsorbent: coconut (Cocos nucifera) bunch waste

Hameed BH, Mahmoud DK, Ahmad AL

J Hazard Mater, 2008 Oct 1;158(1):65-72.
PMID: 18308467 DOI: 10.1016/j.jhazmat.2008.01.034

In this paper, the ability of coconut bunch waste (CBW), an agricultural waste available in large quantity in Malaysia, to remove basic dye (methylene blue) from aqueous solution by adsorption was studied. Batch mode experiments were conducted at 30 degrees C to study the effects of pH and initial concentration of methylene blue (MB). Equilibrium adsorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The adsorption isotherm data were fitted well to Langmuir isotherm and the monolayer adsorption capacity was found to be 70.92 mg/g at 30 degrees C. The kinetic data obtained at different concentrations have been analyzed using a pseudo-first-order, pseudo-second-order equation and intraparticle diffusion equation. The experimental data fitted very well the pseudo-second-order kinetic model.
Development of a novel questionnaire to assess knowledge, attitude and practice towards medical disorders in pregnancy among clinicians

Tan TL, Lau Q, Chiew SC, Thanusha, Mahmoud D, Manisha

Med J Malaysia, 2024 Jan;79(1):52-59.
PMID: 38287758

INTRODUCTION: Maternal medicine is important and complex. It focuses on the care of mothers with comorbidities or medical disorders during pregnancy. To date, there are limited tools to assess clinicians' knowledge, attitude and practice (KAP) in this field.
MATERIALS AND METHODS: This study aims to develop and validate a questionnaire measuring the KAP of clinicians towards maternal medicine. Literature reviews, item generation and multiple experts' reviews were conducted during the questionnaire development phase. Convenient sampling was undertaken for this cross-sectional survey. A total of 168 clinicians from one tertiary hospital and three health clinics participated in thepilot testing using the modified questionnaire. In addition, test-retest was performed on 30 participants to examine its reliability, whilst exploratory factor analysis (EFA) was undertaken to determine its construct validity.
RESULTS: This finalised questionnaire contained 36 items with excellent content validity. Pertaining to test-retest reliability, all knowledge domain items showed Kappa values > 0.20, except item K29; attitude domain items overall Cronbach's alpha was 0.787 with corrected item-total correlation > 0.300 and lastly, all items in practice domain achieved intra-class correlation index > 0.700, except P2.5. EFA supported four factor structures, but six items were removed due to the following reasons: cross loading, negative or poor loading factor (< 0.3).
CONCLUSION: Overall, this instrument has an acceptable psychometric property, content validity, internal reliability and construct validity. It is hope that this questionnaire would be validated in other populations and be used in future research to enrich our understanding of clinicians' KAP towards maternal medicine.

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