Siti Kartini Enche Ab Rahim
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Preferred name
Siti Kartini Enche Ab Rahim
Official Name
Siti Kartini, Enche Ab Rahim
Alternative Name
Rahim, S. K.Enche Ab
Enche Ab Rahim, S. K.
Rahim, Siti Kartini Enche Ab
Main Affiliation
Scopus Author ID
57115278300
Researcher ID
EJE-7983-2022

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Facile synthesis of magnetophoretic augmented adsorbent for water remediation

2024-03 , Chuan Chuan Lim , Ng Qi Hwa , Siti Kartini Enche Ab Rahim , Hoo Peng Yong , Siew Hoong Shuit , Sigit Tri Wicaksono

In this new era of globalization, magnetic adsorbents have gained vast attention from researchers in wastewater treatment applications. In this study, sulphonated magnetic multi-walled carbon nanotubes (S-MMWCNTs) were used to remove methylene blue (MB) from an aqueous solution. The S-MMWCNTs are characterized by various analytical methods to investigate their adsorbent features. Adsorption behaviours of the as-prepared composites affected by solution pH and contact time were systematically studied and discussed. The adsorption kinetic data fit the pseudo-second-order kinetic model well. Moreover, the MB removal efficiency of S-MMWCNTs only drops slightly (~6.5%) after five consecutive adsorption cycles, showing their good stability and recyclability.

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Plant-based calcium silicate from rice husk ash: A green adsorbent for free fatty acid recovery from waste frying oil

2024-02-29 , Zainor Syahira Zainal , Hoo Peng Yong , Abdul Latif Ahmad , Ahmad Zuhairi Abdullah , Ng Qi Hwa , Siewhoong Shuit , Siti Kartini Enche Ab Rahim , Andas J.

Driven by the urgent need for a solution to tackle the surge of rice husk (RH) and waste frying oil (WFO) waste accumulation at a global scale, this report highlights the use of calcium silicates (CS) extracted from acid-pre-treated rice husk ash (RHA) for free fatty acid (FFA) removal from WFO as conventional RHA shows limited FFA adsorption performance. A novel alkaline earth silicate extraction method from acid-pre-treated RHA was outlined. The structural and behavioural attributes of the synthesised CS were identified through BET, SEM-EDS, and XRD analyses and compared to those of RHA. Notable morphology and structural modification were determined, including reducing specific surface areas, mitigating from amorphous to crystalline structure with regular geometric forms, and detecting Si–O–Ca functional groups exclusive to CS adsorbents. A comparison study showed superior lauric acid (LA) adsorption performance by CS absorbents over acid-pre-treated RHA, with a significant increase from 0.0831 ± 0.0004 mmol LA/g to 2.5808 ± 0.0011 mmol LA/g after 60 min. Recognised as the best-performing CS adsorbent, CS-1.0 was used for further investigations on the effect of dosage, LA concentration, and temperature for efficient LA adsorption, with up to 100% LA removal and 5.6712 ± 0.0016 mmol LA/g adsorption capacity. The adsorption isotherm and kinetic studies showed LA adsorption onto CS-1.0 followed Freundlich isotherm with KF = 0.0598 mmol(1-1/n) L(1/n) g−1 & Qe,cal = 3.1696 mmol g−1 and intraparticle diffusion model with kid = 0.1250 mmol g−1 min0.5 & Ci = 0.9625 mmol g−1, indicating rapid initial adsorption and involvement of carboxylate end of LA and the calcium ions on the CS-1.0 in the rate-limiting step. The high equilibrium adsorption capacity and LA adsorption rate indicated that the proposed CS-1.0 adsorbent has excellent potential to recover FFA from WFO effectively.

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Facial synthesis of colloidal stable magnetic nanoparticles coated with high hydrophilic negative charged poly(4‐styrenesulfonic acid co‐maleic acid) sodium for water remediation

2023 , Lim Chuan Chuan , Ng Qi Hwa , Hoo Peng Yong , Siti Kartini Enche Ab Rahim , Mohd Riduan Jamalludin , Amira Mohd Nasib , Sigit Tri Wicaksono , Azzah Dyah Pramata , Siti Zullaikah

The enhancement of the colloidal stability of magnetite nanoparticles (MNPs) for environmental‐related fields has greatly attracted researchers' attention. This study used a high hydrophilic negatively charged polyelectrolyte, poly(4‐styrenesulfonic acid co‐maleic acid) sodium (PSAAS), to enhance the colloidal stability of MNPs. Coating of the naked MNPs with PSAAS polyelectrolyte is a simple and rapid method to obtain colloidally stable MNPs while sustaining the chemical reactivity of MNPs in water purification. The prepared PSAAS‐coated MNPs were characterized by scanning electron microscope, energy dispersive X‐ray, Fourier transform infrared, zeta potential analysis, transmission electron microscope and X‐ray diffraction. Moreover, the colloidal stability and adsorption performance tests of these naked MNPs and PSAAS‐coated MNPs (with different concentrations of PSAAS coated) were investigated and compared. PSAAS‐coated MNPs with 0.001 g/ml PSAAS coating possessed the best colloidal stability and the highest methylene blue (MB) dye removal efficiency (94.53 ± 0.69%). The adsorption isotherm and kinetic studies for the adsorption of MB onto PSAAS‐coated MNPs were well‐described by the Langmuir model and pseudo‐second‐order kinetic model. These magnetic adsorbents, with high separation efficiency, simple and low production cost and recyclable property, are promising as practicable adsorbents in water treatment.

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Sulfonated magnetic multi-walled carbon nanotubes with enhanced bonding stability, high adsorption performance, and reusability for water remediation

2023 , Lim Chuan Chuan , Siew Hoong Shuit , Ng Qi Hwa , Siti Kartini Enche Ab Rahim , Wei Ming Yeoh , Hoo Peng Yong , Soon Wah Goh

In view of the simple and rapid conveniency of magnetic separation, magnetic nanocomposites had notably gained attention from researchers for environmental field applications. In this work, carboxylated magnetic multi-walled carbon nanotubes (c-MMWCNTs) and novel sulfonated MMWCNTs (s-MMWCNTs) were synthesized by a facile solvent-free direct doping method. Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, energy dispersive X-ray, vibrating sample magnetometer, and point of zero charge analyses confirmed the successful doping of the Fe3O4 nanoparticles into the functionalized MWCNTs to form MMWCNTs. Besides, the bonding stabilities of both c-MMWCNTs and s-MMWCNTs were compared, and results showed that s-MMWCNTs possessed more substantial bonding stability than that of c-MMWCNTs with significantly less leaching amount of Fe3O4. The adsorption capacity of s-MMWCNTs was higher than that of c-MMWCNTs owing to the stronger electronegativity sulfonic group in s-MMWCNTs. Moreover, the reusability experiments proved that the adsorbent remained consistently excellent MB removal efficiency (R > 94%) even reused for twelve cycles of batch adsorption. The finding of the present work highlights the simple fabrication of novel s-MMWCNTs and its potential to be served as a promising and sustainable adsorbent for water remediation owing to its enhanced bonding stability, high adsorption performance, magnetic separability, and supreme recyclability.

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