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All Journal The Journal of Pure and Applied Chemistry Research IJFAC (Indonesian Journal of Fundamental and Applied Chemistry) Science and Technology Indonesia Indonesian Journal of Chemistry Communications in Science and Technology Sainmatika: Jurnal Ilmiah Matematika dan Ilmu Pengetahuan Alam Jurnal Kreativitas PKM Molekul: Jurnal Ilmiah Kimia JPPM (Jurnal Pengabdian dan Pemberdayaan Masyarakat) International Journal of Sustainable Transportation Technology Jurnal Altifani Penelitian dan Pengabdian kepada Masyarakat Bulletin of Chemical Reaction Engineering & Catalysis Indonesian Journal of Chemical Science
Addy Rachmat
Department Of Chemistry, Faculty Of Mathematics And Natural Science, Sriwijaya University
Religion Agriculture, Biological Sciences & Forestry Humanities Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Education Engineering Environmental Science Health Professions Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Materials Science & Nanotechnology Mathematics Medicine & Pharmacology Nursing Physics Public Health Social Sciences Transportation

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Photocatalytic degradation of methylene blue and Congo red dyes from aqueous solutions by bentonite-Fe3O4 magnetic Riyanti, Fahma; Hasanudin, Hasanudin; Rachmat, Addy; Purwaningrum, Widia; Hariani, Poedji Loekitowati
Communications in Science and Technology Vol 8 No 1 (2023)
Publisher : Komunitas Ilmuwan dan Profesional Muslim Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21924/cst.8.1.2023.1007

Abstract

This study describes the co-precipitation synthesis of magnetic bentonite-Fe3O4 for photocatalytic degradation of methylene blue and Congo red pigments under visible light. Bentonite-Fe3O4 composites were produced using the mass ratio of 2:1 and 1:1 for bentonite to Fe3O4, respectively. X-ray Powder Diffraction (XRD), Fourier Transform Infra-Red (FTIR), BET surface area, Vibrating-Sample Magnetometer (VSM), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), and Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV DRS) were used to characterize the materials. The bentonite-Fe3O4 (1:1) composite exhibited a greater surface area in comparison to the bentonite-Fe3O4 (2:1) composite with a measured value of 106.6 m2/g. It is a superparamagnetic material with a band gap of 2.25 eV and a saturation magnetization of 69.64 emu/g. The photocatalytic degradation of dye using bentonite-Fe3O4 (1:1) with the initial dye concentration of 25 mg/L, volume of 50 mL, catalyst dose of 0.05 g/L, addition of 3 mL H2O2, and 90 minutes of visible irradiation resulted in 94.34% and 98.45% degradation efficiency of methylene blue and Congo red dyes, respectively. The study determined that the most favorable pH for the photocatalytic degradation of methylene blue was pH 11, whereas the optimal pH for Congo red was found at pH 5. For methylene blue and Congo red dyes, photocatalytic degradation followed pseudo-first-order with the constant rates of 0.0356 min-1 and 0.0348 min-1, respectively. After five cycles of use in the photocatalytic process, the catalyst's degradation efficiency fell into below 5%. This research demonstrated that catalysts could be utilized in wastewater treatment technology.
Optimization Photodegradation of Methylene Blue Dye using Bentonite/PDA/Fe3O4@CuO Composite by Response Surface Methodology Riyanti, Fahma; Hariani, Poedji Loekitowati; Hasanudin, Hasanudin; Rachmat, Addy; Purwaningrum, Widia
Bulletin of Chemical Reaction Engineering & Catalysis 2024: BCREC Volume 19 Issue 2 Year 2024 (August 2024)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.20132

Abstract

This study aims to synthesize bentonite/PDA/Fe3O4@CuO composites as a catalyst for the photodegradation of Methylene blue dye. Composite characterization involves X-ray Diffractometry (XRD), Scanning Electron Microscopy (SEM) with X-ray Energy Dispersion Spectrometry (EDS), UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS), and Vibrating Sample Magnetometer (VSM). Response Surface Methodology (RSM) employs Central Composite Design (CCD) to optimize photodegradation by varying dye concentration, irradiation time, and catalyst dose. The bentonite/PDA/Fe3O4@CuO composites exhibit a saturation magnetization value of 54.82 emu/g and a band gap of 2.1 eV. The optimization revealed that concentration and dose significantly impact the photodegradation efficiency. A quadratic model is suitable for modeling the photodegradation of Methylene blue dye using bentonite/PDA/Fe3O4@CuO composites, as determined by analysis of variance (ANOVA). The optimal conditions for achieving maximum photodegradation efficiency were identified as a dye concentration of 10 mg/L, an exposure time of 90 min, and a catalyst dose of 1.67 g/L. Under these parameters, the photodegradation process exhibited a remarkable efficiency of 100%. The Bentonite/PDA/Fe3O4@CuO composites exhibited strong stability, efficiency, and recyclability. After six photodegradation cycles, there was a 5.18% decrease in photodegradation efficiency. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
Utilization of Antioxidant Fagraea fragrans fruit as Phytocosmetics Basir, Dasril; Rachmat, Addy; Julinar, Julinar; Eliza, Eliza
IJFAC (Indonesian Journal of Fundamental and Applied Chemistry) Vol 9, No 1 (2024): February 2024
Publisher : IJFAC (Indonesian Journal of Fundamental and Applied Chemistry)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24845/ijfac.v9.i1.41

Abstract

The objective is to test the antioxidant activity of methanol (MeOH) extracts,  ethyl acetate (EtOAc) fractions, and an isolated compound of F. fragrans (tembesu) fruitby using DPPH method respectively. Antioxidant is one of the main components of phytocosmetic beside anti-inflammatory, anticancer, and antimicrobial activities while phytocosmetics of F. fragrans fruit is the cosmetics that mainly use extracts or components derived from this fruit only, without preservatives, such as products that do not contain water, oils, dry ointments, or hydro-alcoholic solutions. As a result, The IC50 values of the MeOH extracts, EtOAc fractions, and the isolated compound were 186.5 ± 0.52 microgram/mL, 357.2 ± 0.59 microgram/mL, and 5.658 microgram/mL respectively. The MeOH extracts exhibited moderate antioxidant activity while the isolated compound exhibited strong antioxidant activity. The total flavonoid content of the MeOH extracts and EtOAc fraction was measured by a colorimetric assay, using reagents of 1 M sodium acetic and 10% aluminum chloride. The EtOAc fraction had a total flavonoid content of 4.505 mgQE/g-extract and total phenolic content of 13.732 mgGAE/g-extract while the MeOH extracts had a total flavonoid content of 9.088 mg QE/g-extract and total phenolic content of 23.34 mgGAE/g-extract respectively. Therefore, the utilization of MeOH extracts or the isolated compound of this fruit may be beneficial for developing skincare phytocosmetics and personal care products. Keywords: Phytocosmetics, antioxidant, Fagraea fragrans, tembesu fruit
Hydrogen Production from Aluminum Waste Using the Aluminum-Water Method with Potassium as Activator Amelia, Icha; Rohendi, Dedi; Rachmat, Addy; Syarif, Nirwan; Yulianti, Dwi Hawa; Sya'baniah, Nyimas Febrika; Adhiyanti, Nurmalina; Adelia, Ory; Normah, Normah
IJFAC (Indonesian Journal of Fundamental and Applied Chemistry) Vol 9, No 2 (2024): June 2024
Publisher : IJFAC (Indonesian Journal of Fundamental and Applied Chemistry)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24845/ijfac.v9.i2.111

Abstract

Research on hydrogen production from aluminum waste using the aluminum-water method using potassium as an activator has been successfully carried out. This research aims to determine the performance of the potassium activator in hydrogen production with variable water volume and potassium percentage. Hydrogen gas production is carried out using 60 mesh aluminum waste. Optimum conditions were achieved when a mass of 1 gram of aluminum was reacted with an additional volume of water of 1.5 mL, and 7% w/w of the activator mass, with the production of hydrogen gas of 553 mL at a production rate of 69 mL/minute.
Investigation of Mixed MeOH:EtOH Ratio and Air Supply on MEA Performance in Direct Alcohol Fuel Cell (DAFC) Yulianti, Dwi Hawa; Rohendi, Dedi; Majlan, Edy Herianto; Rachmat, Addy; Sya’baniah, Nyimas Febrika
Science and Technology Indonesia Vol. 10 No. 4 (2025): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2025.10.4.1012-1019

Abstract

Methanol (MeOH) and ethanol (EtOH) are commonly used fuels in Direct Alcohol Fuel Cells (DAFC). The advantages of these two fuels are influenced by electrochemical reactions centered around the Membrane Electrode Assembly (MEA). In this study, Pt/C catalyst was used on the cathode and Pt-Ru/C on the anode, with catalyst loadings of 2, 4, 6, 8, and 10 mg/cm2. The anode and cathode were characterized using Cyclic Voltammetry (CV), while the conductivity properties were evaluated through Electrochemical Impedance Spectroscopy (EIS). The Open Circuit Voltage (OCV) of the MEA in a single DAFC cell reached 0.65 V, with the highest value observed at a MeOH:EtOH volume ratio of 70:30 at concentrations of 3 M for MeOH and 2 M for EtOH. In addition to oxidation at the anode, oxygen reduction plays a significant role in the MEA performance on the cathode side. The oxygen supply to the cathode increased the power density by 52.17% at the optimal blower voltage of 5 V.
The Influence of Hydrogen Flow Rate and Humidifier Temperature on Performance of a PEMFC with Ti-Co/C Catalyst Adhiyanti, Nurmalina; Rohendi, Dedi; Utama, Muhammad Prima; Syarif, Nirwan; Rachmat, Addy; Yulianti, Dwi Hawa; Normah, Normah
IJFAC (Indonesian Journal of Fundamental and Applied Chemistry) Vol 10, No 3 (2025): October 2025
Publisher : IJFAC (Indonesian Journal of Fundamental and Applied Chemistry)

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

This study explores the effect of hydrogen flow rate and humidifier temperature on the performance of the Membrane Electrode Assembly (MEA) using Ti-Co/C catalyst at the cathode and Pt/C at the anode in a single-cell Proton Exchange Membrane Fuel Cell (PEMFC). MEAs were fabricated by the spraying method and characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) to determine their electrochemical surface area (ECSA) and conductivity. The results showed that the optimized ECSA value reached 8.38 cm2/g, and the electrical conductivity was 3.76 × 10-8 S/cm. The best performance was achieved at a hydrogen flow rate of 100 mL/min and room temperature humidification. Under the hydrogen flow rate test, the maximum power density reached 0.364 mW/cm2, while in the humidifier temperature variation, a maximum power density of 0.375 mW/cm2  was obtained at a current density 2.4 mA/cm2. These findings suggest that Ti-Co/C is a promising low-cost catalyst alternative to Pt and that operational conditions play a critical role in MEA performance
Preparation of Palm Kernel Shell Binchotan for Radio Frequency Energy Harvesting Sya'baniah, Nyimas Febrika; Syarif, Nirwan; Rohendi, Dedi; Rachmat, Addy; Syahputra, Rio Aldo
IJFAC (Indonesian Journal of Fundamental and Applied Chemistry) Vol 10, No 3 (2025): October 2025
Publisher : IJFAC (Indonesian Journal of Fundamental and Applied Chemistry)

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Research on the development of radio frequency energy harvesting slabs from palm kernel shells binchotan has been done. The slabs were characterized by using XRD and FTIR intrumentations to determine their crystallography and functional groups. The electrical response of slabs was measured on impedance spectroscopy instrumentation. The conductivity, impedance, and dielectric constant were calculated from impedance spectroscopy data. Diffractograms showed crystalline carbon and confirmed with the existence of peaks, at 2θ, 24.5° and 44.56°. FTIR analysis showed that carbon palm shells have the absorption length is in the range of wave numbers 1100 – 1200 cm-1 for CO of carboxylic acid, aldehyde, ketone and ester, from 1475 to 1600 cm-1 for C=C aromatic ring and double peaks in 1900 – 2100 cm-1 for conjugated C-C. The slabs conductivity varies from 1 to 7 mScm-1. Impedance values for the slabs vary from 1.5 to 2.4 ohm. Dielectric constants for the slabs range from 0.42 to 140.
Processing of Tofu industrial wastewater by electrocoagulation method using aluminum (Al) electrode at various electrical current and contact time Rachmat, Addy; Fatma, Fatma; Pratama, Nisa Manora; Musifa, Eva
Indonesian Journal of Chemical Science Vol. 14 No. 1 (2025): Indonesian Journal of Chemical Science
Publisher : Prodi Kimia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/ijcs.v14i1.18787

Abstract

This research aims to determine the effect of varying voltage and contact time on reducing levels on Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Dissolved Solids (TDS) and ammonia as well as increasing pH values ​​in tofu industrial wastewater by electrocoagulation using Aluminum electrodes. There were 4 variations of voltage (10,20,30,4 0A) and 5 variations of contact time (30,60,90,120,150 minutes). Analysis of COD levels and ammonia levels was carried out using a UV-Vis spectrophotometer, analysis of TSS levels gravimetrically using Whatman filter paper No. 42, analysis of TDS levels with gravimetrically, and analysis of pH values ​​by a pH meter. The best results were obtained from treatment at voltage of 40 A and a contact time of 150 minutes with the highest efficiency of reducing COD, TSS, TDS, ammonia levels respectively at 90.35; 92; 66; 85% and the highest increase in pH value was 108%. The results of the diversity analysis or Tukey's advanced test showed that at the 5% level each treatment had a significant effect on reducing COD, TSS, TDS and ammonia levels as well as increasing the pH value. Chemical kinetics analysis of the reduction in COD and TSS levels showed results that were close to first orde linear and obtained R2 and k values ​​respectively of (0.9904; 0.0164); (0.9952; 0.0182) at voltage variation of 40 A
Effect of Hydrogen Flow Rate on MEA Performance with a Three-Catalyst-Layer Pt/C Configuration Yulianti, Dwi Hawa; Rohendi, Dedi; Budiman, Rahmadi; Firanda, Dera Okta; Rachmat, Addy; Sya'baniah, Nyimas Febrika
IJFAC (Indonesian Journal of Fundamental and Applied Chemistry) Vol 10, No 2 (2025): June 2025
Publisher : IJFAC (Indonesian Journal of Fundamental and Applied Chemistry)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24845/ijfac.v10.i2.146

Abstract

An essential component in Proton Exchange Membrane Fuel Cells (PEMFCs) is the Membrane Electrode Assembly (MEA), which facilitates the electrochemical reaction between hydrogen and oxygen to generate electrical energy. This study examines the effect of varying hydrogen gas flow rates on the performance and durability of a Pt/C-based MEA. The MEA used in this research measures 6.5 cm × 30 cm with a catalyst loading of 2 mg/cm². The electrode is constructed in three layers of catalysts to maximize interfacial contact within the catalyst layer. The tested hydrogen flow rates were 100, 200, 300, and 400 mL/min. Performance evaluation was conducted through polarization (I–V) and power (I–P) curve measurements. The results indicated optimal performance at a 200 mL/min flow rate, with a maximum power density of 3.563 mW/cm² and a current density of 10.256 mA/cm². Durability testing was carried out under a constant current of 2 A for 12 hours and showed a voltage drop of 24.35% after 10 hours of operation. Electrochemical characterization using Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), and Linear Sweep Voltammetry (LSV) yielded an Electrochemical Surface Area (ECSA) of 1.477 × 10⁻⁵ m²/g, electrical conductivity of 3.218 × 10⁻⁴ S/cm, and an electric charge of 4.2 × 10⁻⁶ C.
Biosourced Reduced Graphene Oxide and Its Application for Methylene Blue Adsorption Rachmat, Addy; Ahadito, Bijak Riyandi; Suryani, Sri; Meiliza, Cici; Hidayati, Nurlisa; Julinar, Julinar; Said, Muhammad
The Journal of Pure and Applied Chemistry Research Vol. 14 No. 3 (2025): Edition September-December 2025
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2025.014.03.7926

Abstract

Graphene oxide and reduced graphene oxide have been widely studied as a biomass-sourced alternative to graphene for their various capabilities, e.g. as adsorbent. This publication reports the preparation of graphite (g), graphene oxide (GO), and reduced graphene oxide (rGO) from coconut shell (1) and sugarcane bagasse (2) using matoa leaves extract as reducing agent, characterized by XRD, FT-IR, and Raman spectroscopy. The X-ray diffractogram showed 2θ peaks between 22.8°–23.8° for g1, GO1, and rGO1, and between 23.6°–25.8° for g2, GO2, and rGO2. FT-IR spectra of both sets of GO and rGO showed common peaks of O–H (~3400 cm–1), C–H (~2900 cm–1), and C–OH (~1600 cm–1), while also some noticeable differences between the sets. Raman spectra of both rGO showed D peak (~1400 cm–1), G peak (~1700 cm–1), and weak 2D peaks (2700–3300 cm–1) with ID/IG of 0.93 and 0.91 for rGO1 and rGO2, respectively. The obtained g, GO, and rGO were used as adsorbent for methylene blue dye. The adsorption study involved variation in dye concentration, contact time, and amount of adsorbent. It was found that rGO performs best as adsorbent compared to GO and g, with maximum adsorption capacity of 22.308 μg/mg (rGO1) and 47.533 μg/mg (rGO2). Adsorbents prepared from sugarcane bagasse were found to perform better due to its easiness of carbonization compared to coconut shell.
Co-Authors A.M. Ramadhan Adelia, Ory Adhiyanti, Nurmalina Ahmad Fatoni Aldes Lesbani Aldi Herbanu Amelia, Icha Anisa Fitri Amatullah Bakri Rio Rahayu Bijak Riyandi Ahadito Budiman, Rahmadi Dasril Basir Dea Radestia Rahmah Dedi Rohendi Denada, Laellia Desnelli Desnelli Dwi Hawa Yulianti Dwi Hawa Yulianti Edy Herianto Majlan, Edy Herianto Elfita Elfita Eliza Eliza Eliza Eliza Fahma Riyanti Fanani, Muhammad Zainal Fatma Fatma Fatma Fatmawati Fatmawati Ferlinahayati Ferlinahayati Firanda, Dera Okta Handayani Citra Pratiwi Hardi Aji Badarwi Hasanuddin Hasanuddin Hasanudin hasanudin Hasanudin Hasanudin Hasanudin Hasanudin Hasanudin, Hasanudin Hermansyah Hermansyah Hermansyah Julinar Julinar Julinar Julinar Meiliza, Cici MUHAMMAD SAID Muhammad Said Muhammad Said Muhammad Said Muhammad Said Muhammad Said Musifa, Eva Nabila Aprianti Nirwan Syarif Nirwan Syarif Nirwan Syarif Nirwan Syarif, Nirwan Normah Normah, Normah Nurlisa Hidayati Nurlisa Hidayati Nurmalina Adhiyanti Poedji Loekitowati Hariani Poedji Loekitowati Hariani Pratama, Nisa Manora Rahmah, Dea Risfidian Mohadi Risfidian Mohadi Rizki, Widya Twiny Salni Salni Salni Salni Salni Sari, Fera Rahma Sri Suryani Sya'baniah, Nyimas Syabaniah, Nyimas Febrika Syahputra, Rio Aldo Syarif, Nirwan Sya’baniah, Nyimas Febrika Tarmizi Taher Utama, Muhammad Prima Widia Purwaningrum Yulianti, Dwi Yulianti, Dwi Hawa