Zulfakar Mokhtar
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Preferred name
Zulfakar Mokhtar
Official Name
Zulfakar, Mokhtar
Alternative Name
Zulfakar, M.
Mokhtar, Zulfakar
Mokhtar, Z.
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Scopus Author ID
34772072800
Researcher ID
HJA-6996-2022

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Potential of Pretreated Spent Coffee Ground as Adsorbent for Oil Adsorption

2022-01-01 , Nasaruddin N.F.N. , Hairul Nazirah Abdul Halim , Siti Khalijah Mahmad Rozi , Zulfakar Mokhtar , Tan L.S. , Jusoh N.W.C.

Spent Coffee Ground (SCG) has the potential of becoming a low-cost adsorbent for oil removal. However, the effectiveness of SCG as an oil adsorbent is limited by its hydrophilicity. In this work, chemical pretreatment of SCG with acid and alkali was evaluated as a means of enhancing its performance for adsorbing palm cooking oil. The surface morphology of raw and pretreated SCG samples was characterised using a Scanning Electron Microscope (SEM). The functional groups were analysed using Fourier Transform Infrared (FTIR) spectroscopy. A comparison between adsorption performances was performed in terms of contact time in batch adsorption experiments to determine the adsorption capacity of SCG-based adsorbents with oil. The SEM results showed that more developed pores were present on the acid- and alkali-treated SCG samples compared to on the raw SCG sample, while the FTIR results indicated the elimination of hydrophilic cellulose and hemicellulose on these samples. According to these results, both acid- and alkali-treated SCG have better tendencies of adsorbing oil compared to raw SCG. The maximum oil adsorption capacity (2.549 g/g) occurred after 150 min of contact time between alkali-treated SCG adsorbents and oil.

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Removal of naproxen using low-cost Dillenia Indica peels as an activated carbon

2022-01-01 , Fadirah Fadzail , Masitah Hasan , Zulfakar Mokhtar , Naimah Ibrahim

A batch adsorption process of naproxen (NPX) using activated carbon derived from Dillenia Indica peel was performed at the laboratory scale. NPX was selected as an adsorbate due to its toxicity and large occurrence in water. The study was conducted to examine the ability of prepared activated carbon in adsorbing the NPX. The adsorption was conducted at various initial concentrations of NPX, contact time, adsorbent dosage, and pH. Results of batch adsorption showed that the maximum adsorption was reached at lower pH and adsorbent dosage of 0.4 g. 8 h is needed for the adsorption to reached equilibrium. Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm have been used to analyse the properties of the adsorption process. The data are best suited for the Langmuir and Temkin isotherm and the adsorption follows a pseudo-second order model for kinetic study. The results suggest that the adsorption behave as a monolayer and the process is controlled by chemisorption mechanism. The adsorption capacity of 10.76 mg/g concluded that the activated carbon prepared from Dillenia Indica peel is effective in removing NPX from the water.

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Photocatalytic degradation of phenol in a fluidized bed reactor utilizing immobilized TiO2 photocatalyst: Characterization and process studies

2011 , Zulfakar Mokhtar , Hairul Nazirah Abdul Halim , H.M.R. Akmal , M. Abdul Rahman

Remediation of hazardous materials in water has emerged as a top priority over the years. Organic pollutants in water are one of the major constituents in water pollution. Phenol is one of the organic pollutants which are commonly found in the effluent of industries such as petroleum refineries and petrochemicals. Conventional treatment techniques such as filtration and flocculation and carbon adsorption have limitations of their own. Thus, photocatalysis offers a possible alternative in treating wastewater effluent containing phenols. This study attempts to evaluate photocatalytic degradation of phenol in a fluidized bed reactor. Immobilized TiO2 supported onto quartz sand was used as the photocatalyst and characterized using SEM, EDX and XRD analysis. The performance of the supported photocatalyst is evaluated in different operating parameters such as photocatalyst loading and initial phenol concentration.

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Performance of fatty acid-modified spent coffee grounds as a potential adsorbent for oil adsorption

2022-11-18 , Nasaruddin N.F.N. , Hairul Nazirah Abdul Halim , Siti Khalijah Mahmad Rozi , Zulfakar Mokhtar , Tan L.S. , Jusoh N.W.C.

Problems caused by fats, oils, and grease (FOG) in sewer systems have escalated over the years. FOG produced from households, restaurants, stalls, and food processing facilities have contaminated water resources through the sewer system. Thus, trace removal of oil from wastewater is a necessary measure to ensure minimal discharge of FOG into the environment. In the present study, due to the high volumes of coffee waste with no commercial value being generated daily, spent coffee grounds (SCG) were exploited as an oil adsorbent. However, due to their low hydrophobicity, SCG tend to have limited oil adsorption capacity. In this work, SCG underwent pre-treatment using alkali and were further modified with waste cooking oil (WCO) that contained free fatty acids (FFAs) at different ratios (1:10, 1:20, and 1:30) in order to enhance their oil adsorption performance. The performance of the synthesised adsorbents was tested in a batch adsorption process at different contact times. From the batch adsorption test, the highest oil adsorption capacity (2.807 ± 0.086?g/g) was observed using the 1:10 ratio of SCG to FFAs-WCO within 180?min of contact time.

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Adsorption of diclofenac sodium using low-cost activated carbon in a fixed-bed column

2022-12-15 , Fadirah Fadzail , Masitah Hasan , Naimah Ibrahim , Zulfakar Mokhtar , Asih A.Y.P. , Syafiuddin A.

In recent years, the presence of pharmaceutical contaminants, such as diclofenac sodium (DCF) in water bodies and their potential influence on aquatic organisms gained much attention. As a result of high demand and usage by consumers, in addition to incomplete removal during wastewater treatment, pharmaceutical contaminants will end up on water surfaces. To mitigate this problem, the elimination of DCF by employing activated carbon derived from Dillenia Indica peels was evaluated. The adsorption of DCF was performed in a continuous process. The findings showed that the adsorption of DCF was favorable at a lower flow rate, greater bed height, and initial DCF concentration, with the highest removal percentage of 44.93%. To assess the characteristics of the breakthrough curve of DCF, the adsorption data were used to match three distinct adsorption models, namely, Boharts and Adam, Yoon-Nelson, and Thomas. The breakthrough results were well-fitted with these models, as the values of R2 for all models and parameters were higher than 0.88. Thus, it was concluded that the activated carbon from Dillenia Indica can effectively remove DCF from an aqueous solution.

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Performance of rubber seed shell adsorbents for removal of methylene blue dye in aqueous solution

2021-02-23 , Thevdarshni Chanderan , Masitah Hasan , Zulfakar Mokhtar , Naimah Ibrahim

Regeneration of rubber seed shell (RSS) in producing an effective low-cost activated carbon (AC) through chemical activation using H3PO4. Adsorption of methylene blue (MB) by raw, AC1 (impregnation ratio 1:1) and AC2 (impregnation ratio 1:3) carbons were analyzed to discover its adsorption capacity. The effects of various experimental parameters: pH of solution, initial concentration, contact time and adsorbent dosage were analyzed. Characterization of adsorbents produced were performed using SEM, ash content, iodine number and BET. Overall performance of the adsorbents was investigated by employing the optimum values obtained in the batch adsorption studies. This study revealed that the carbon with higher impregnation ratio (AC2) has the highest removal efficiency of MB at 91.4%. Specific surface area, iodine adsorption number and ash content for AC2 are 317.6 m2/g, 676.9 mg/g and 2.6%, respectively. This study revealed the primacy of chemically activated carbons with higher impregnation ratio (AC2) for the removal of MB.

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Performance of Alkali-Treated Spent Coffee Ground as Potential Adsorbent for Oil Adsorption

2023-06-09 , Nasaruddin N.F.N. , Hairul Nazirah Abdul Halim , Siti Khalijah Mahmad Rozi , Zulfakar Mokhtar , Tan L.S. , Jusoh N.W.C.

The increase in food industrial and domestic activities have led to massive generations of oily wastewater with high proportions of fat, oil, and grease (FOG). The growing awareness of the detrimental effects of oil pollutants on the aquatic population and the economy, has made the minimal discharge of FOG into the environment a compulsory mitigative measure. In this work, spent coffee grounds (SCGs) were exploited as an oil adsorbent to minimize the amount of SCGs that are primarily discarded as waste. SCGs were pre-treated with alkali to enhance their performance for adsorbing oil. Batch adsorption tests that consisted of contact time, adsorbent dosage, and temperature for oil adsorption, were carried out to analyse the performance of the alkali-treated SCGs. Based on the results, the maximum oil adsorption capacity was obtained after 150 min of contact time between 0.5g of alkali-treated SCG adsorbents and oil, at 25 °C. These alkali-treated SCGs have also shown the potential for converting wastes into efficient green oil adsorbents.

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Kinetics and Effects of Process Parameters on Oil Adsorption using Activated Carbon from Rubber Seed Kernels (Hevea brasiliensis)

2023-01-01 , Aswadi M.A.H. , Hairul Nazirah Abdul Halim , Nasaruddin N.F.N. , Siti Khalijah Mahmad Rozi , Zulfakar Mokhtar , Tan L.S. , Jusoh N.W.C.

Wastewater contaminated with oil discharged from food processing industries need to be treated properly in order to avoid clogging the drainage and sewerage systems. The removal of oil via the adsorption technique using biomass as a low-cost adsorbent was proposed in this study. Rubber seed kernels (RSKs) were used as the raw material to synthesise activated carbon. The RSKs were impregnated with 10 wt% of phosphoric acid (H3PO4) and carbonised at 500 °C to produce rubber seed kernel activated carbon (RSKAC). Different parameters were included in batch adsorption studies, namely, contact time (30 to 240 min), activated carbon dosage (0.5 to 2.5 g), and temperature (25 to 65 °C). The performance of each process parameter was evaluated based on the adsorption capacity of oil onto the synthesised RSKAC. Pseudo-first order and pseudo-second order models were applied to analyse oil adsorption kinetics using RSKAC. Based on the experimental results, the highest oil adsorption was achieved at 150 min of contact time, 2.5 g of RSKAC, and at a temperature of 35 °C. Oil adsorption using RSKAC in this study followed the pseudo-second order kinetics model. These findings revealed that RSKAC could be synthesised as a low-cost adsorbent for oil adsorption.

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