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Facile and Environmentally Friendly Synthesis of Low-defect Few-Layers Graphene (FLG) Using Combined Shear Exfoliation Methods Amri, Amun; Wulandari, Revika; Fabryza, Dhina; Sunarno, Sunarno; Heltina, Desi; Bahri, Syaiful; Sarma, Deki; Miran, Hussein A.; Rahman, M. Mahbubur; Altarawneh, Mohammednoor; Jiang, Zhong Tao
Journal of Engineering and Technological Sciences Vol. 57 No. 5 (2025): Vol. 57 No. 5 (2025): October
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2025.57.5.4

Abstract

This study presents an environmentally friendly and scalable method for synthesizing high-quality few-layer graphene (FLG) through a combination of turbulence-assisted shear exfoliation (TASE) and high shear exfoliation (HSE) techniques. By systematically varying the high-shear mixer (HSM) speed (3000–5000 rpm) and processing time (1–3 hours), we precisely controlled key material attributes, including the number of graphene layers, crystallinity, lateral size, and defect density. Optimal conditions (5000 rpm, 3 hours) resulted in FLG with ~2–3 layers, confirmed by a symmetric 2D peak with a full-width at half-maximum (FWHM) of ~35 cm⁻¹ and a high I2D/IG ratio (~0.6), indicating excellent structural integrity. The ID/IG ratio (~0.1) further verified the presence of minimal defects, predominantly edge vacancies rather than oxidative disruptions. Raman imaging revealed a dominance of zigzag edge chirality, while TEM and PSA analyses demonstrated control over lateral size (~396.5 nm) and particle uniformity. The application of household dishwashing liquid as a green surfactant innovatively enabled selective and pure exfoliation. This work highlights how precise modulation of shear parameters can directly influence graphene quality, paving the way for sustainable large-scale production of low-defect FLG.
Fabrication and Photocatalytic Performance of ZnO-Biochar Composites for Eliminating Dye Waste Heltina, Desi; Yoselino, Danil; Nabellia; Dumaria, Agustina; Amila, Khairati; Komalasari; Sembiring, Maria Peratenta; Amri, Amun; Jiang, Zhong Tao
Communications in Science and Technology Vol 10 No 2 (2025)
Publisher : Komunitas Ilmuwan dan Profesional Muslim Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21924/cst.10.2.2025.1795

Abstract

The synthesis of the ZnO-biochar composite from palm kernel shell biomass waste has been accomplished through the utilization of thesolvothermal method, yielding a satisfactory outcome. The resulting composite, a combination of ZnO and biochar, has been utilized in the degradation of methylene blue waste compounds. The objective of this research is to synthesize ZnO-biochar composites from palm shells, and to determine the optimal solvothermal temperature and duration. This research was initiated with the preparation of palm shells into biochar. Subsequently, the ZnO-biochar composite was synthesized with variable solvothermal temperatures and solvothermal times. The ZnO-biochar composite was characterized using analytical techniques including SEM-EDX, FT-IR, XRD, BET and UV-vis DRS. The most effective degradation of methylene blue was exhibited by the ZnO-biochar composite sample synthesized at a solvothermal temperature of 180 ̊C and a solvothermal time of 10 hours, achieving a degradation of 88.29%. The enhanced photodegradation performance of this composite sample is attributed to its high surface area, capacity for visible light absorption, and the dimensions of the active crystals, which can account for the high performance of the ZnO-biochar composite for photocatalytic degradation.