Nur Hidayatul Nazirah Kamarudin

Zeolites are porous materials with regular nanochannels, high surface area, tunable acid sites, excellent thermal and hydrothermal stability, and outstanding catalytic performance. These properties make them indispensable in energy and chemical engineering, environmental remediation, selective adsorption, and clean energy technologies. However, conventional hydrothermal synthesis suffers from high energy consumption, strong alkali corrosion, excessive template usage, and the generation of salt containing and organic waste liquids, limiting its sustainability. Consequently, green chemistry based synthesis strategies have become a major research focus, aiming to optimize resource utilization, environmental impact, and material performance simultaneously. This review summarizes recent advances in green zeolite synthesis, including solvent free or low solvent methods, low template or template free strategies, directed agent synthesis, ionothermal synthesis, dry gel conversion, and the use of renewable silicon and aluminum resources. The underlying reaction mechanisms and performance control principles are critically discussed. Through representative case studies, the review highlights how these approaches reduce activation energy, improve atom efficiency, minimize waste generation, and enable precise control of crystal morphology and pore structures. Future perspectives include AI-driven materials design, accurate topology prediction, machine learning-assisted structural characterization and generation, and the optimization of synthesis conditions.

An organic-free, high alkalinity strategy for Y zeolite synthesis was developed to provide an efficient and environmentally friendly route for zeolite production. The effects of synthesis parameters and seed crystals on crystallization were systematically investigated, and kaolin was used as an alternative silica alumina source.After ultra stabilization, USY/ASA composites were prepared by the sol-gel method. The physicochemical properties are characterized by means of XRD, SEM,BET,FT-IR and NH₃-TPD, as well as hydrocracking activity of USY/ASA. Under optimal conditions (90 °C, 28 h, 10% directing agent, and molar ratio of 3Na2O：Al2O3：8.5-9.5SiO2：75H2O), the obtained Y zeolite exhibited a relative crystallinity of 182.35%, a framework SiO2/Al2O3 ratio of 4.8, and a yield of 50.73 wt.%. A The NiW/USY/ASA catalyst showed excellent hydrocracking performance for n-decane, achieving 76.41% C10 conversion and 56.07% medium-oil yield at the reaction conditions of 340 ℃, 4.0 MPa, 500 Nm3/m3 hydrogen-to-oil ratio and WHSV 4 h-1 .This work establishes an environmental friendly, template-free strategy for Y zeolite synthesis and demonstrates its strong potential for high-performance hydrocracking catalysts due to its tailored acidity and graded pore architecture.

Polycyclic aromatic hydrocarbons (PAHs) are hazardous organic compounds defined by their long-lasting nature, carcinogenicity and mutagenicity, posing environmental and health risks. Conventional PAH removal methods usually have high costs, low efficiency and potentially produce secondary contaminants. Graphene-based magnetic covalent organic frameworks (MCOFs) emerged as an alternative, offering high surface area, tuneable functionality and superior magnetic separability. Graphene-based MCOFs facilitate strong π–π interactions, hydrophobic effects and improved adsorbent stability, leading to more efficient PAH removal. The distinctive focus of this review is on deep eutectic solvents (DESs) as a green modification strategy to further optimize adsorption efficiency by lowering reaction temperature, reducing synthesis time and eliminating the use of hazardous organic solvents. This review presents a comprehensive study of graphene-based MCOFs and DES functionalized adsorbent synthesis, adsorption mechanisms and their environmental applications in enhancing PAH adsorption performance as the next-generation sustainable materials for large-scale PAH remediation. Collectively, these advances align with the principles of green chemistry and are anticipated to contribute to global efforts towards the sixth, seventh and fourteenth sustainable development goals, namely clean water and sanitation, affordable and clean energy and the protection of aquatic ecosystems.

Peri-implantitis is a growing pathological concern for dental implants which aggravates the occurrence of revision surgeries. This increases the burden on both hospitals and the patients themselves. Research is now focused on the development of materials and accompanying implants designed to resist biofilm formation. To enhance this endeavor, a smart method of biofilm inhibition coupled with limiting toxicity to the host cells is crucial. Therefore, this research aims to establish a proof-of-concept for the pH-triggered release of chlorhexidine (CHX), an antiseptic commonly used in mouth rinses, from a titanium (Ti) substrate to inhibit biofilm formation on its surface. To this end, a macroporous Ti matrix is filled with mesoporous silica (together referred to as Ti/SiO₂), which acts as a diffusion barrier for CHX from the CHX feed side to the release side. To limit release to acidic conditions, the release side of Ti/SiO₂ is coated with crosslinked chitosan (CS), a pH-responsive and antimicrobial natural polymer. Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX) and Fourier transform infrared (FTIR) spectroscopy confirmed successful CS film formation and crosslinking on the Ti/SiO₂ disks. The presence of the CS coating reduced CHX release by 33% as compared to non-coated Ti/SiO₂ disks, thus reducing the antiseptic exposure to the environment in normal conditions. Simultaneous differential scanning calorimetry and thermogravimetric analyzer (SDT) results highlighted the thermal stability of the crosslinked CS films. Quartz crystal microbalance with dissipation monitoring (QCM-D) indicated a clear pH response for crosslinked CS coatings in an acidic medium. This pH response also influenced CHX release through a Ti/SiO₂/CS disk where the CHX release was higher than the average trend in the neutral medium. Finally, the antimicrobial study revealed a significant reduction in biofilm formation for the CS-coated samples compared to the control sample using viability quantitative polymerase chain reaction (v-qPCR) measurements, which were also corroborated using SEM imaging. Overall, this study investigates the smart triggered release of pharmaceutical agents aimed at inhibiting biofilm formation, with potential applicability to implant-like structures.

Peri-implant infection is rapidly becoming an – if not the most – important clinical challenge for indwelling medical devices. To alleviate the global rise in antibiotic use for the treatment of such infections, a plethora of biomaterials/bioengineering-based antimicrobial strategies are emerging to restrict or ideally to eliminate microbial adhesion and biofilm formation on implant surfaces. Yet, the development of such approaches faces specific challenges, like biocompatibility concerns, reduced antimicrobial effectiveness, long-term stability issues and antibiotic resistance development, which limit translation to the clinic. This review provides insights into the antimicrobial activity of current state-of-the-art biomaterial-based approaches to address the aforementioned issues. Translational research strategies and regulatory framework are also emphasised as key elements facilitating clinical implementation of anti-infective biomaterials. This review closes with the vision that the integration of computational tools and experimental databases using artificial intelligence (AI) would provide new insights for the accelerated development of next-generation biomaterial-based antimicrobial strategies.

Copper and iron-based bimetallic nickel catalysts supported on Mesostructured Silica Nanoparticles (MSNs) with compositions of 50% Ni–5% Cu/MSN and 50% Ni–5% Fe/MSN were prepared using an impregnation method, and they were compared with a monometallic 50% Ni–MSN catalyst for their activity and stability in methane decomposition reaction. The influence of promoters, such as Cu and Fe, at different reaction temperatures (700 °C, 800 °C and 900 °C) was investigated. The results revealed that the Cu and Fe-promoted catalysts significantly increased the hydrogen yield in methane decomposition compared with the unpromoted catalyst. This could be attributed to the formation of Ni–Cu and Ni–Fe bimetallic alloys in the catalysts, respectively, and this favored the stability of the catalysts. With increasing reaction temperature, the hydrogen yield also increased. However, the hydrogen yield and the lifetime of the nickel catalyst were enhanced upon the addition of iron compared to copper at all the reaction temperatures. The analysis conducted over the spent catalysts validated the formation of multi-walled carbon nanotubes with a bamboo-like internal channel over the catalysts along with a high crystallinity and graphitization degree of the carbon produced.

The tendency to use cellulose fibrils for direct ink writing (DIW) of three-dimensional (3D) printing has been growing extensively due to their advantageous mechanical properties. However, retaining cellulose in its fibrillated forms after the printing process has always been a challenge. In this study, cellulose macrofibrils (CMFs) from oil palm empty fruit bunch (OPEFB) fibers were partially dissolved for consistent viscosity needed for DIW 3D printing. The printed CMF structure obtained from optimized printing profiles (volumetric flow rate, Q_v = 9.58 mm/s; print speed, v = 20 mm/s), exhibited excellent mechanical properties (tensile strength of 66 MPa, Young’s modulus of 2.16 GPa, and elongation of 8.76%). The remarkable structural and morphological effects of the intact cellulose fibrils show a homogeneous distribution with synthesized precipitated calcium carbonate (CaCO₃) nanoparticles. The shear-aligned CMF/CaCO₃ printed composite exhibited a sustained therapeutic drug release profile that can reduce rapid release that has adverse effects on healthy cells. In comparison with the initial burst release of 5-fluorouracil (5-FU) by CaCO₃, the controlled release of 5-fluorouracil can be varied (48 to 75%) with the composition of CMF/CaCO₃ allowing efficient release over time.

This study examined the process of synthesising biodegradable nanofibres made up of polycaprolactone (PCL) and chlorophyllin sodium copper (CSC) through electrospinning for scaffolding in tissue engineering. Scaffolds provide a platform for cell regeneration for repairing damaged human tissues or organs. However, the issue lies in developing scaffolding that will provide a favourable environment for cell attachment and proliferation. One way to address this concern is to add CSC, which has been widely used in biomaterial applications, to the nanofibres. The structure and morphology of the nanofibres in this research were determined by using a scanning electron microscope (SEM), and their chemical properties were tested by using Fourier-transform infrared spectroscopy (FTIR). Moreover, the diameter and adhesive force of the nanofibres were investigated by using an atomic force microscope (AFM). The SEM examination revealed that the PCL/CSC nanofibres lost their fibrous structure, and the FTIR results proved that the nanofibres synthesised by electrospinning still consisted of PCL and CSC. The AFM examination showed that the diameter and adhesive force of PCL/CSC nanofibres were less than those of PCL nanofibres. This outcome resulted from the CSC’s inability to generate fibres on its own. Furthermore, its noncrystalloid structure prevented it from providing inner enhancement for PCL nanofibres. Hence, further studies are needed to ensure that PCL/CSC nanofibres can be used as an innovative type of scaffolding to provide an appropriate environment for living cells.

This study applied ultrasonic irradiation technique to remove acid orange 52 (AO52) and in the meantime utilizing the potential adsorbent, Lapindo volcanic mud (LVM). LVM was collected from the erupted mud in Sidoarjo, Indonesia and calcined prior the adsorption process. Previously in another study, Lapindo was proven to be efficient for adsorption of dyes in single adsorption method. In this study, the combination of adsorption with ultrasound, or as known as sono-sorption shows that the adsorptivity increased from 95.54 mg/g to 129.5 mg/g. The isotherm study shows that this process obeyed Langmuir isotherm model with adsorption capacity of 833.33 mg/g. The enhancement of sono-sorption method as compared to conventional method is believed to be resulted from the facilitated mass transfer driven by the ultrasound, along with the adsorption ability of LVM. The kinetic study fit to the pseudo second order equation.