I W. Sutapa
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Halu Oleo University, Kendari, Indonesia.

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Unveiling Non-Covalent Molecular Interactions: A Comprehensive Review Integrating DFT and Crystallographic Insights W. O. N. Haryanti; I W. Sutapa; Sahidin; L. Ahmad; L. O. A. N. Ramadhan
International Journal of Acta Material Vol. 2 No. 1 (2025): August 2025
Publisher : Faculty Mathematics and Natural Sciences, Halu Oleo University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62749/ijactmat.v2i1.18

Abstract

Non-covalent interactions (NCIs) are crucial in elucidating molecular recognition, supramolecular architecture, and material properties. This review synthesizes findings from 20 recent studies (2013–2025), with a focus on key interaction types: hydrogen bonding, π–π stacking, Van der Waals forces, and less prevalent modes such as chalcogen bonding and excited-state interactions. Computational methodologies, particularly dispersion-corrected density functional theory (DFT), benchmark datasets (e.g., S22, HB300SPX), and emerging machine learning (ML) corrections, have markedly enhanced the accuracy of NCI modeling. Experimental techniques, including X-ray diffraction and infrared/Raman spectroscopy, continue to substantiate theoretical predictions. Hydrogen bonds are predominant in influencing structural stability and crystal packing, while π–π interactions play a vital role in stabilizing aromatic systems. Van der Waals interactions are particularly significant in layered materials and adsorption phenomena. Recent advancements, such as neural network potentials (NNPs) and non-empirical functionals (e.g., r²SCAN+MBD@HF), provide accurate predictions even in complex environments. This review underscores the interplay between theoretical and experimental approaches and highlights prospective directions in modeling weak interactions across a range of chemical systems.
Optimisation of Asphalt Extraction from Asbuton Using Microwave-Assisted Extraction (MAE) Method Hikmayani; I W. Sutapa; Sahidin; L. O. Ahmad
International Journal of Acta Material Vol. 2 No. 1 (2025): August 2025
Publisher : Faculty Mathematics and Natural Sciences, Halu Oleo University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62749/ijactmat.v2i1.19

Abstract

Buton natural asphalt (Asbuton) is a strategic non petroleum bitumen resource with promising potential in road construction. However, conventional extraction methods such as Soxhlet and reflux suffer from long processing times, high energy demand, and excessive solvent use. This review evaluates Microwave-Assisted Extraction (MAE) as a green and efficient alternative for extracting bitumen from Asbuton. MAE employs rapid dielectric heating, enabling selective bitumen release while minimizing solvent consumption. Key process variables, including solvent polarity, solid-to-solvent ratio, temperature, extraction time, microwave power, and system pressure are critically reviewed. Comparative data show that MAE significantly improves extraction yield and operational efficiency. In addition, Response Surface Methodology (RSM) is discussed as a modeling tool to optimize variable interactions and identify ideal extraction conditions. Visual aids such as flow diagrams and comparative tables are used to clarify performance metrics and technical constraints. The review also outlines major challenges in MAE implementation, including microwave penetration in low-dielectric matrices and the need for scalable reactor designs. Overall, this paper provides a comprehensive perspective on MAE-based extraction for Asbuton, offering insight into its advantages, limitations, and directions for future research and industrial application.
Application of Rice Husk Silica Ash Activated using NH4OH to Reduce Calcium Ion (Ca2+) Levels in Brackish Water L. Harimu; Mutmainnah; Dahlan; W. O. Mulyana; E. C. Mandasar; I W. Sutapa; A. Kamari
International Journal of Acta Material Vol. 2 No. 1 (2025): August 2025
Publisher : Faculty Mathematics and Natural Sciences, Halu Oleo University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62749/ijactmat.v2i1.21

Abstract

A study was conducted to investigate the efficacy of NH4OH-activated rice husk ash silica in mitigating calcium ion (Ca²⁺) concentrations in brackish water. The primary objective of this research was to evaluate the adsorption capacity of NH4OH-activated rice husk ash silica for Ca²⁺ ions dissolved in brackish water. The experimental methodology employed various adsorption parameters, including pH levels (5, 6, 7, 7.5, 8, 9), adsorbent masses (0.01, 0.025, 0.05, 0.1, 0.2 g), contact times (15, 30, 45, 60, 75 minutes), and concentration levels (25, 50, 75, 100 ppm) for Ca²⁺ ions. The findings indicated that optimal adsorption occurred at an adsorbent mass of 0.025 grams, a pH of 7.5, a contact time of 30 minutes, and a concentration of 50 ppm, resulting in an adsorption capacity of 67.2 mg/g. Furthermore, under optimal conditions, the application of activated rice husk ash silica as an adsorbent in brackish water demonstrated an NH4OH adsorption capacity of 40 mg/g, with a brackish water concentration of 40 mg/g. Therefore, it can be concluded that NH4OH-activated rice husk ash silica is a viable adsorbent for reducing calcium ion (Ca²⁺) levels in brackish water.