Pusat Pengajian Sains Kimia - Monograf

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    Modelling And Simulation Of Cationic Dye Adsorption Using Modified Metal-Organic Framework-5 (MOF-5)
    (Universiti Sains Malaysia, 2021-07-01)
    Wan Mazlan, Wan Hamizan
    Modelling and simulation of cationic dye adsorption by using modified Metal-Organic Framework-5 was studied. Mathematical model was developed based on a two-resistance model which included external mass transfer coefficient and pore diffusion coefficient that controls the mass transfer process in batch adsorption. MATLAB R2020b software was used to estimate the mass transfer parameters which are mass transfer coefficient (kf) and pore diffusion coefficient (Dp) by matching the simulation data with the experimental data from literature. The value of kf and Dp were estimated to be 66.8 m/s and 2.1514×10-7 m2 /s respectively. By using the estimated parameters, simulation results showed that the model provided good correlation with the experimental data based on different initial concentrations. The estimated parameters were used to study the adsorption of Methylene Blue (MB) by using modified MOF-5 under different factors such as modification of MOF-5, initial dye concentration, temperature and the mass of adsorbent. It was concluded that the dye removal efficiency was higher for modified MOF-5 (H6P2W18O62/MOF-5). Not only that, the lower initial dye concentration, higher temperature and higher adsorbent mass also result in higher dye removal efficiency.
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    Amphoteric Adsorbent Coating For Pharmaceutical Waste (Diclofenac Sodium) Removal
    (Universiti Sains Malaysia, 2021-06-01)
    Abdul Taib, Muhammad Haziq
    The removal of diclofenac sodium (DCF) using a novel amphoteric absorbent coating (AAC) has been presented by this thesis. The formulation of the adsorbent was through a formation of a layer on the surface of a cotton cloth through facile method application using acrylic polymer emulsion (APE), smectite-based clay powder, and cationic polyelectrolyte (EPIDMA). SEM and EDX analysis were conducted for the characterization of the adsorbent coating. The experiments were carried out to study the effect of EPIDMA dosage, concentration, contact time, temperature, and pH of DCF solution on the removal efficiency of the DCF. The optimized percentage removal of DCF is at 77.06% at DCF concentration of 50 mg/L, temperature of 30°C and pH of 3 for 5 hours. Adsorption isotherms were developed to study the adsorption mechanism of the adsorption. This study has shown that the aforementioned parameters influence the performance of the AAC for DCF removal. With high removal efficiency and reusability, AAC was found to be a promising adsorbent for DCF removal from pharmaceutical wastewater system.
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    Parameters that effect the antioxidant profile and phenolic compound from centella asiatica extract
    (2018-06)
    Muhammad Ridhwaan Mohd Bakhtiar
    Centella asiatica is commonly used as a spice and medicinal herb due to its antioxidant activity and total phenolic contents. Water, methanol and ethanol were used to analyze the amount of antioxidant activity and total phenolic contents. Ethanol extraction at 7 hr showed the highest value of DPPH scavenging activity with 65.06 % (IC50=291.00 mg/ml) followed by water with 63.48 % (IC50=408.26 mg/ml) and methanol with 62.39 % (IC50=515.86 mg/ml). The data from the experiment had been compared with the BHT standard curve in order to finalised the best solvent based on DPPH scavenging activity. The increase in DPPH scavenging activity contributes by high amount of TPC. Ethanol gave the highest TPC followed by water and methanol at 228.57 mgGAE/g, 115.63 mgGAE/g and 64.41 mgGAE/g, respectively. This is because ethanol has stronger hydroxyl group compared to methanol and water. The results were compared with the standard curve of gallic acid. As the time increase the phenolic compound from C.asiatica also increase, this is because the phenolic content contributed by capacity of extract due to the time of extraction. The active component that contributed to the phenolic compound is asiaticoside. As The retention time using HPLC was 2.60 min while the standard time was 2.75 min. The result showed that ethanol is the best solvent for extraction of active component with antioxidant activity and phenolic contents of C. asiatica compared to methanol and water.
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    Optimizing purity and recovery of hydrogen from syngas by equalized psa using palm kernel shell activated carbon adsorbent
    (2018-06)
    Shanthini Gobi
    This thesis is concerned with the adsorbent preparation, design and operation of Pressure Swing Adsorption (PSA) unit at optimum condition for the effective syngas separation processes. The aim of the study is directed towards optimizing the purity and recovery of hydrogen gas from the syngas. The first detailed study presented in this work deals with the preparation of activated palm kernel shell (ACPKS) and its characterization study. In adsorbent preparation, optimum activation temperature of about 800ºC has been used. Whereas, the characterization study reveals that the specific surface area of the prepared adsorbent is around 697.67m²/g with pore volume and pore size of 0.35m3/g and 2.01nm respectively. The average particle size of the adsorbent sample is recorded as 0.11µm. Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) analysis uncovers the spongy structure of the highly amorphous ACPKS. Breakthrough studies at varying adsorption pressure were executed and 3 bar adsorption pressure is chosen for the subsequent optimization study. Based on the software analysis, the optimum operating condition of the PSA unit is predicted at 5 minutes adsorption and blowdown time. A systematic and rigorous methodology are employed towards attaining the similar data as predicted by the software. The PSA study which operated at the optimum operating condition yielded hydrogen purity of up to 99.978% with recovery of 80.014%. The results obtained shows a close agreement with the predicted data given by the software.
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    Iron-modified composite adsorbent coating for acid red 1 removal and its regeneration feasibility by heterogeneous fenton-like process
    (2018-06)
    Chew, Jian Yee
    Adsorption is widely used technique in wastewater treatment because the process is low cost, ease of operation and efficient. However, regeneration of spent adsorbents is usually restricted by the strong interactions between the surface of adsorbents and adsorbates. It would be very economical if the spent adsorbents can be regenerated and reused for many cycles. Hence, this current research had been focussed on the feasibility of heterogeneous Fenton process to regenerate Acid Red 1 (AR1) loaded composite adsorbent coating (CAC). The iron-modified bentonite was synthesised to replace swelled bentonite in the original formulation of CAC (APE-bent-EPIDMA/CF). The results showed that the adsorption of AR1 with initial concentration of 50 ppm was very efficient and equilibrium was achieved within two hour for both formulations. After modified with iron, the removal rate of AR1 in aqueous solution was higher than that of swelled bentonite. Ability of heterogeneous Fenton process to regenerate the spent APE-Febent-EPIDMA/CF was evaluated under the assistance of UV and without UV (in dark condition). The effect of acid and base on the desorption of AR1 was also studied using 0.1 M of hydrochloric acid (HCl) and 0.1 M sodium hydroxide (NaOH). The initial concentration of hydrogen peroxide used was 8.82 mM. After regeneration process for 3 hours under the UV assistance with addition of 0.1 M NaOH, the APE-Febent-EPIDMA/CF was still able to retain high percentage removal of AR1 (>80%) up to five cycles of adsorption. The findings revealed that sodium hydroxide is a good elution agent to desorb AR1 (anionic dye) from the APE-Febent-EPIDMA/CF coating.