The purification of Tronoh silica sand is an important step in expanding technical applications of this silica sand. However no research on purifying of Tronoh silica sand has been reported. This study is focused on ball milling technique as a preliminary technique for Tronoh silica sand purification. The objectives are to study the effect of ball milling to the purification of the silica sand and to analyze its characteristics after the ball milling process. The samples before and after milling process were analyzed by using XRF, XRD, SEM and TEM. Results showed that the purity of SiO2 was increased, the size of the particles has been reduced and the surface area has increased. The crystalline phases for the silica before and after 4 hour milling time were remained constant.
Affordable hydrophobic hollow fibre membranes were prepared using kaolin and alumina based ceramic powders via a combined phase inversion and sintering technique, followed by a grafting with fluoroalkylsilane (FAS). The crux of the matter in this paper is to study the changes in the properties of the hollow fibre membranes (gas permeation, mechanical strength, pore size, porosity, tortuosity, morphology, and contact angle) by the addition of alumina (Al2O3) to the pure kaolin with mono or multiparticle sizes. By varying the overall loading and particle size of alumina addition, different morphologies of the membranes were obtained due to the differences in the path lengths during phase inversion process for each solvent and nonsolvent exchange. The successful grafting with FAS was evidenced by the increase in contact angle from nearly equal to zero degree before grafting to 140° after grafting. Kaolin–alumina-4, one of the hollow fibres fabricated in this work, achieved a mean pore size of 0.25 μm with the bending strength of 96.4 MPa and high nitrogen permeance of 2.3×10-5 mol·m-2·Pa-1·s-1, which makes the hollow fibre most suitable for the membrane contactor application.
Fungal diseases, such as Ganoderma boninense, pose significant economic threats to oil palm plantations. Conventional fungicides, including synthetic and biofungicides, have been employed to manage these diseases, but they come with limitations such as environmental impact and limited efficacy. Other than that, weed infestation is another serious challenge in agricultural systems such as oil palm plantations. Synthetic herbicides and bioherbicides have been widely use to mitigate this problem but herbicides still have limitation in terms of health concerns. Recent advancements in nanotechnology have introduced nano-enabled crop protection most notably nanofungicides and nanoherbicides as promising alternatives, offering improved penetration and delivery of active ingredients. However, challenges such as non-uniform size distribution and polydispersity hinder their effectiveness. This review explores the potential of supercritical fluid technology (SFT) to overcome these limitations, providing a green and sustainable approach to nanoparticle production. SFT offers distinct advantages, including moderate operating temperatures and non-toxic solvents, aligning with the principles of green chemistry. The unique properties of SFT-produced nanomaterials, particularly their high surface area-to-volume ratio, demonstrate significant potential for membrane technology applications beyond agricultural contexts. Future perspectives highlight the need for further research to optimize SFT processes for agricultural applications, aiming to enhance the scalability and cost-effectiveness of nanofungicide and nanoherbicide production. The integration of SFT in agriculture could revolutionize plant disease and weed management, contributing to sustainable and eco-friendly practices.
The use of kaolin as a source of silica and alumina for synthesis of zeolite has been widely reported with various compositions and processing routes. However, since kaolin is highly influenced by geological origin and geographical formation, coupled with the processing method, two different crude kaolin were obtained at various locations in Peninsular Malaysia to serve as precursor for synthesis of zeolite. Hydrothermal treatments were made at reasonable low temperature of 90°C in an oven. The synthesized product was then analyzed using X-ray diffraction and scanning electron microscopy, to evaluate the potentials of the process and the product. The outcome of the analysis suggested that the breaking down of the clay structure and the armophization process can improve raw material reactivity. However, the crystallinity and composition of the crude kaolin together with appropriate incubation time can greatly influence the synthesis process and the product.
In this work, the novel imprinted zeolite (IZ) was synthesized, and its properties and performance in terms of adsorption of p-Cresol, which represent the protein-bounded uremic toxins in aqueous phase under phosphate buffer saline, were studied and compared with the synthesized zeolite-Y (ZeoY-S) and commercial CBV 100 zeolite-Y (ZeoY-C). The ZeoY-S was synthesized from sodium aluminate, NaOH, H2O and SiO2 under aging for 24 h at room temperature and hydrothermal condition for 24 h at 100 °C, with an initial composition of 10SiO2:Al2O3:4Na2O:180H2O. The ZeoY-S has been modified by using the imprinting technology to produce the IZ via the use of p-Cresol as a template. The p-Cresol successfully imprinted on the zeolite-Y was proved through the multipoint Brunauer-Emmett-Teller (BET) and the performance of IZ that was compared to ZeoY-S and ZeoY-C. Based on the BET results, it proves that the pore size of IZ is in accordance with the target compound, which is p-Cresol at 0.79 nm. This modification was able to adsorb p-Cresol 2.5 and 3.5 times higher than ZeoY-S and ZeoY-C can, respectively. Langmuir and Freundlich adsorption isotherm models, together with the pseudo-first and -second order and intra-particle diffusion kinetics models, were used to investigate the adsorption behavior of p-Cresol on the zeolites. The IZ has 4.30 times greater competitive molecules than ZeoY-S and the properties of IZ were not influenced by the content of other phenolic group uremic toxins as competitive molecules. It can be concluded that the micropores of zeolite as adsorbent can be modified using the imprinting technology in order to increase its sensitivity and selectivity towards p-Cresol.
Zeolitic imidazole framework 8 (ZIF-8) nanoparticles were successfully synthesized in an aqueous solution at the ambient condition with a relatively low molar ratio of zinc salt and an organic ligand, Zn+2/Hmim (1: 8). ZIF-8 has remarkable thermal and chemical stability, tunable microporous structure, and a great potential for absorption, adsorption, and separation. Various physicochemical characterization techniques like X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), attenuated total reflected infrared spectroscopy (ATR-IR), thermogravimetric analysis (TGA), and surface area with pore textural properties by micromeritics gas adsorption equipment were performed to investigate the effect of base type additive triethylamine (TEA) on the morphology, crystallinity, yield, particle and crystal size, thermal stability and microporosity of ZIF-8 nanoparticles. The total quantity of basic sites and carbon dioxide (CO2) desorption aptitude was also calculated using CO2 temperature-programmed desorption (CO2-TPD) system. The pure ZIF-8 nanoparticles of 177 nm were formed at TEA/total mole ratio of 0.002. Furthermore, the size of ZIF-8 nanoparticles was decreased to 77 nm with increasing TEA/total mole ratio up to 0.004. The structures, particle sizes and textural properties of ammonia modified ZIF-8 particle can easily be tailored by the amount of aqueous ammonium hydroxide solution. The smallest ZIF-8 nanoparticles obtained were 75 nm after ammonia modification which shows excellent thermal stability and improved microporosity. The ZIF-8 basicity and uptakes of CO2 improved with TEA and ammonia modification which followed the order: A25ml–Z4 > Z4 > Z3 > Z5 > Z2 > A50ml–Z4. The proposed economical and efficient synthesis method has great potential for large-scale production of ZIF-8.
Polyethersulfone (PES) hollow fiber membranes were fabricated via the dry‐wet phase inversion spinning technique, aiming to produce an asymmetric, micro porous ultrafiltration hollow‐fiber specifically for hemodialysis membrane. The objective of this study is to investigate the effect of spinning conditions on the morphological and permeation properties of the fabricated membrane. Among the parameters that were studied in this work are air gap distance, dope extrusion rate, bore fluid flow rate, and the take‐up speed. The contact angle was measured to determine the hydrophilicity of the fibers. Membrane with sufficient hydrophilicity properties is desired for hemodialysis application to avoid fouling and increase its biocompatibility. The influences of the hollow fiber's morphology (i.e., diameter and wall thickness) on the performance of the membranes were evaluated by pure water flux and BSA rejection. The experimental results showed that the dope extrusion rate to bore fluid flow rate ratio should be maintained at 1:1 ratio to produce a perfectly rounded asymmetric hollow fiber membrane. Moreover, the flux of the hollow fiber spun at higher air gap distance had better flux than the one spun at lower air gap distance. Furthermore, spinning asymmetric hollow fiber membranes at high air gap distance helps to produce a thin and porous skin layer, leading to a better flux but a relatively low percentage of rejection for BSA separation. Findings from this study would serve as primary data which will be a useful guide for fabricating a high performance hemodialysis hollow fiber membrane. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43633.
The discharge of oily wastewater and offshore oil spills contaminates the biotic and aquatic environment and ultimately result in the destruction of the ecosystem. Recently, the application of ceramic membranes has gained prodigious attention due to its efficiency in oil-water separation process. Ceramic membranes developed from inorganic materials are considered as the most promising technology for the treatment of industrial wastewater. Besides, different types superhydrophobic-superoleophilic substrates are being developed using various substrate materials to tailor its purpose for higher efficiency. Nonetheless, fouling and clogging phenomena restrict the performance of ceramic membrane in oil-water separation. This review emphasizes the recent innovation on superhydrophobic methods for the modification of ceramic membranes for oil-water recovery. It comprises of an overview of the preparation technique of ceramic membrane using various techniques. Moreover, the different types of hydrophobic ceramic membrane modification using chemical agents and consequent effects on oil-water separation were discussed in detail. Furthermore, the technical challenges and issues associated with the applications of superhydrophobic-superoleophilic ceramic membrane for oil-water separation were discussed. Finally, future direction in the research of cost-efficient approach to produce superhydrophobic ceramic membranes for oil-water filtration process is enumerated.
Day and night photocatalysis offers a novel approach by integrating the electron storage principle to ensure effectiveness even in the absence of light. A groundbreaking vanadium pentoxide / graphitic carbon nitride (V2O5 / g-C3N4) composite photocatalyst functioned as g-C3N4 absorbs and utilizes visible light, while V2O5 transfers and stores more photo-generated electrons. The composite with a 2 % loading ratio showed the highest CIP removal efficiency: 91 % during daytime and 75 % at night. Successful nighttime degradation was due to stored electrons in V5+/ V4+ pairs, confirmed by XPS analysis of the reduction of V5+ to V4+. The study proposes detailed mechanisms for charge generation, reactive species action, and reactions during both day and night photocatalysis. This has significance for water treatment in real environmental settings with lower energy requirements, overcoming light-related limitations.
No abstract is provided for this article.
No abstract is provided for this article.
This research was conducted to study on PANI-Cu-Ni nanocomposite thin film sensors for Leptospira detection. PANI-Cu-Ni nanocomposite was deposited onto glass substrate by spin-coating technique. The morphological and structural properties of the thin films have been analysed using atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX). Leptospira bacterium existence was determined by sensitivity and selectivity tests through I-V measurement and EIS analysis. From the result, FESEM and EDX investigations showed the abnormality of nanoparticle thin film ranging in size from 40 to 60 nm in the existence of metal in substrates, revealing the engagement between the microbe and thin film surface. PANI-Cu-Ni nanocomposite thin films were successful and effective in detecting the existence of Leptospira in water. PANI-Cu0.6-Ni0.4 thin films demonstrated greater sensitivity for the identification of Leptospira. From the sensitivity plot, the increasing of Ni has decreased the sensitivity performance.
Reduced graphene oxide (RGO) was successfully decorated with homogeneous highly dispersed palladium nanoparticles (PdNPs) by a novel single-step hydrothermal-assisted formic acid reduction reaction without the use of any surfactants. The structure, surface morphology, and elemental composition of the as-prepared PdNP-RGO electrocatalyst were extensively characterized. The PdNP-RGO electrocatalyst demonstrated outstanding electrocatalytic activity (8.65 mA/cm2) toward the methanol oxidation reaction (MOR) in an acidic medium that is 1.4 times higher than PdNP-decorated Vulcan XC72 (6.2 mA/cm2) and also comparable with that of Pd-based electrocatalysts in alkaline media from the previous reports. Furthermore, the as-prepared PdNP-RGO electrocatalyst also shows remarkable stability performance for the MOR in an acidic medium and thus offer new insights into the processing method of an outstanding electrocatalyst at the anode electrode in the direct methanol fuel cell with reasonable cost, clean and facile synthesis approach.
This study proposed an enhanced water purification separation that was carried out at ambient temperature and low-pressure system. ZnO and PVA layers were deposited on the outer surface of Al2O3 hollow fibre membrane, and this composite membrane was used to separate synthetic salt solutions with a concentration of 40,000 ppm. The salt solution was introduced on the outer surface of PVA–ZnO–Al2O3 hollow fibre membrane, and distilled water was flowed through the lumen as draw solution. The PVA–ZnO–Al2O3 hollow fibre membrane showed a water flux of 25.70 kg m2 h−1 with 93.9 % NaCl rejection. Al2O3 hollow fibre used in this work possessed asymmetric structure with permeability of 11.6 mD and was identified as a medium that cause a significant pressure drop within the separation system. A considerable pressure drop occurred in the porous region of the ceramic hollow fibre, causing water to vaporise. This phenomenon resulted in water evaporation at the interface between the dense sponge-like region of Al2O3 hollow fibre and PVA–ZnO membrane, thus created a positive flux for enhanced salt separation.
