Indonesian Journal of Chemical Studies

The Potency of Photocatalytic Membrane Bioreactor for Wastewater Treatment: A Brief Review

Lathifah Puji Hastuti — 2025-06-30

Membrane bioreactors (MBR) are a promising method for wastewater treatment that combines microbial degradation with membrane separation. MBRs offer efficient and sustainable wastewater treatment by combining biological processes with membrane filtration, providing high-quality effluents for reuse. The advantages of MBRs, such as their compact design, reduced sludge production, and water recycling potential, make them increasingly significant in addressing global water scarcity and pollution challenges. Nevertheless, the issue of biofouling persists as a notable obstacle, primarily caused by the interplay of bacteria, membrane surfaces, and the release of extracellular polymeric substances (EPS). Integrating photocatalysts into MBR membranes offers a new method to reduce fouling. This study provides a comprehensive overview of current research on the membrane modification using photocatalysts in MBR systems, focusing on the existing challenges and prospects in this field. Despite these potential advantages, research on improving MBR membrane performance through photocatalysis is sparse. To ensure the sustainability of this technology, it is essential to consider important factors, such as reactor configuration, kinetics, fouling processes, economic feasibility, and scaling issues

Formulation of Digested Beverage Cans and Iron Plate Wastes as a Coagulant for Adequate Hygiene of Fresh River Water

Mutiara Gita — 2025-03-30

In terms of hygiene and sanitation, ensuring the availability of qualified water for those purposes remains challenging to perform under certain conditions. Accordingly, efforts to provide simple water processing technology are ongoing and innovatively developed. This study displayed an innovative approach to producing coagulants for water processing by utilizing metal salts obtained synthetically from used beverage cans and iron plates through the electrolysis principle and characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning Electron Microscopy - The Energy Dispersive X-ray (SEM-EDX), subsequently. After mixing with calcium hypochlorite and adding to water sample, subsequently, the coagulant showed the ability to reduce the turbidity level and several categories of impurities, i.e., nitrate, nitrite, dissolved Manganese, Cr⁶⁺ ion, and microbial levels. Future research and development in formulating coagulants derived from digested beverage cans and iron plate wastes hold significant potential to advance sustainable and efficient water treatment technologies, ensuring improved hygienic quality of fresh river water while contributing to waste valorization and environmental protection.

Reflection Loss Improvement by Cerium Addition in Chitosan-Hydroxyapatite Film as Stealth Drone Candidate

Riyanti Putri — 2025-05-30

Radar is a detection and tracking technology commonly applied to monitor environmental conditions. Its ever-growing capabilities pose a serious challenge to military operations because they increase the risk of being detected by the enemy. On the other hand, unmanned aircraft (drones) are increasingly widespread in gathering information. However, the effectiveness of this technology can be reduced due to exposure to radar waves that allow detection. Therefore, developing coating materials that can absorb radar waves is an urgent need to increase the effectiveness of military equipment. The composites developed were derived from chitosan obtained from crustacean waste, hydroxyapatite from eggshell waste, and the rare earth metal cerium obtained from Lapindo Mud. Composites containing cerium metal (Ce) have higher radar signal absorption capabilities than samples without Ce, as evidenced by VNA measurements showing increased absorbance in the 100 MHz - 8.5 GHz frequency range. SEM tests indicate that cerium particles increase the density and homogeneity of the pore structure, with a size range of 17–24 µm. FTIR characterization revealed that Ce was physically bound to the chitosan-HAp composite. Mechanically, the composite with Ce had a maximum tensile stress of 9.512 MPa and a strain of 9.512%, while without the addition of Ce, a stress of 9.529 MPa and a strain of 25.512% was obtained. These findings indicate that integrating rare earth metals in chitosan-HAp composites can improve the material's capability to absorb radar waves, thus having broad prospects for applications in defence technology.

Formulation and Characterization of Herbal Solid Soap Enriched with Cinnamon (Cinnamomum burmanii) and Aloe vera Peel Extracts

Narsih — 2025-05-31

This study aims to develop a solid soap formulation using natural ingredients by combining cinnamon (Cinnamomum burmanii) extract and Aloe vera peel extract, which are known for their antibacterial, antioxidant, and moisturizing properties. The research involved several stages, including the extraction of cinnamon and Aloe vera, soap formulation with varying cinnamon and Aloe vera extract concentrations, and testing of physicochemical properties and antibacterial activity against Escherichia coli. The formulated soaps were evaluated for moisture content, free alkali levels, pH, foam stability, antibacterial inhibition zones, and skin irritation. The results showed that increasing the concentrations of cinnamon and Aloe vera peel extracts significantly affected the soap’s characteristics. The optimal formulation was obtained with 15% cinnamon extract and 6% Aloe vera peel extract (A3B3), yielding a moisture content of 2.44%, free alkali content of 1.70%, pH of 11.8, and an antibacterial inhibition zone of 1.28 mm, without any skin irritation. FTIR analysis identified functional groups such as aldehydes, alkanes, aromatics, and hydroxyls, which were associated with the bioactive compounds responsible for antibacterial and moisturizing effects. The presence of cinnamaldehyde in cinnamon and saponins in Aloe vera contributed to the soap’s enhanced antimicrobial and skin-conditioning properties. Furthermore, Fourier-transform infrared spectroscopy (FTIR) analysis identified key functional groups responsible for the soap’s bioactivity. These findings suggest that incorporating herbal extracts into soap formulations can improve their functional benefits, making them a promising alternative for natural skincare products with antibacterial protection and skin health benefits.

Synthesis and Characterization of Titanium Dioxide/Graphene Nanoplatelets Nanocomposites via Planetary Ball Milling for Military Radar Absorbing Materials

Gita Resty Amalia — 2025-06-08

Stealth technology is widely used in the military field to avoid enemy detection. Consequently, there has been a significant surge in research related to radar-absorbing materials (RAMs). Titanium dioxide (TiO₂) and graphene nanoplatelets (GNPs) are promising materials for developing RAMs. Combining TiO₂ as a semiconductor with GNPs as a conductive material could increase the ability to absorb microwaves through a more effective energy dissipation mechanism. In our study, TiO₂ and GNPs were fabricated using the planetary ball milling method. The structure and morphology of the resulting nanocomposites were evaluated using Field Emission Scanning Electron Microscopy with Energy Dispersive Spectroscopy with Energy Dispersive Spectroscopy (FE-SEM EDS) and X-ray Diffraction (XRD). FE-SEM observations showed that TiO₂ nanoparticles were attached to the surface of layered GNPs. XRD analysis showed a decrease in the peak intensity of the TiO₂/GNP nanocomposites compared to pure TiO₂ due to the addition of carbon elements. The performance of RAMs was evaluated using a Vector Network Analyzer (VNA) in the X-band (8-12 GHz) range with a 3-mm thickness. The VNA analysis indicated that the TiO₂/GNP nanocomposites exhibited the optimal reflection loss (RL) of -30.72 dB at a frequency of 8.42 GHz, accompanied by a through power of 99.91%. Consequently, TiO₂/GNP nanocomposites demonstrated promising potential as a military RAM.

Fabrication and Characterization of Graphene Nanoplatelets/Zinc Oxide Nanocomposites as a Military Radar Absorbing Material

Anselmo Bima Rasendriya — 2025-06-16

Stealth aircraft have the capability to intercept radar waves. One common technique involves the use of radar-absorbing materials (RAMs). This study focused on the synthesis of advanced lightweight functional materials derived from advanced carbon and semiconductor compounds for microwave absorbing through mechanical homogenization. Graphene nanoplatelets (GNP) and Zinc Oxide (ZnO) possess excellent dielectric and magnetic loss capability due to their thermal conductivity, small particle size, large surface area, disordered structure, and lightweight nature. The GNP and ZnO were developed as advanced carbon and semiconductor nanocomposites using Planetary Ball Milling (PBM) at a ratio of 1:1. This approach aimed to improve the structure, morphology, and electromagnetic performance of the materials. A comparison between the nanocomposite materials and their precursors was conducted to clarify the advantages of using nanocomposites. FE-SEM showed the layered carbon sheets in GNP. XRD exhibited the alteration in the crystallite structure of ZnO, while FTIR spectroscopy confirmed the presence of specific functional groups. In addition, the GNP/ZnO nanocomposites showed strong microwave polarization capabilities. Notably, the GNP/ZnO nanocomposite achieved the lowest RL value compared to the precursor materials with a value of -28.21 dB at 8.45 GHz and a thickness of 3 mm in the scope of X-band range. While the through power was calculated at 99.84%. Through mechanical homogenization, a well-structured disordered crystallite layered material was fabricated for military RAMs. In the industrial sector, GNP/ZnO nanocomposites showed promising potential as a lightweight and advanced functional material for future stealth aircraft applications.