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rony sihombing
politeknik negeri bandung
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Asphydroxel: Asphalt Carbon Dioxide Capture by Synthesis of Potassium Hydroxide for Utilization of Palm Oil Bunch Ash Waste rony sihombing
Journal of Green Science and Technology Vol 7 No 3 (2023): Journal of Green Science and Technology Vol.7 No.3 Special Edition : Applied scie
Publisher : Faculty of Engineering, Universitas Swadaya Gunung Jati

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33603/jgst.v7i3.95

Abstract

Environmental pollution is the most common problem faced by Indonesia, for example, industrial waste. The country of Indonesia once occupied the first position in Southeast Asia, as a country with the worst air quality. In addition, Indonesia is the largest producer of crude palm oil (CPO) and palm oil plantations in the world. The industry produces the most solid waste in the form of empty palm oil bunches and requires a large area to store it. In order to reduce the storage area needed, empty palm oil bunches are burned to ashes or palm oil fuel ash (POFA). Therefore, we have the idea of absorbing CO2 gas and utilizing POFA as a mixture of concrete and asphalt, by converting it into a potassium chloride compound. Then, the electrolysis process is carried out to produce potassium hydroxide compounds. The potassium hydroxide compound will later be mixed with asphalt to produce Asphydroxel asphalt, which absorbs carbon dioxide. In implementing Asphydroxel, several parties are involved, such as oil palm smallholders, palm oil mills, asphalt company research teams, asphalt companies, and the government. It is predicte that this idea will prevent the buildup of bunch ash waste and air pollution which cause climate change
Batch Adsorption Performance of a KOH-Activated Corn Cob Carbon–Calcined Fly Ash Composite for Multi-Pollutant Removal Nurcahyo; Unung Leoanggraini; Alfiana Adhitasari; Ghaniari Putri; Khumaira Maulani Wijaya; Rony Sihombing
Sainteknol : Jurnal Sains dan Teknologi Vol. 24 No. `1 (2026): `June 2026
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v24i`1.63136

Abstract

The discharge of dye and heavy metal-containing wastewater remains a major environmental challenge, highlighting the need for low-cost, effective adsorbents. This study evaluated the batch adsorption performance of a composite adsorbent KOH-activated corn cob carbon combined with calcined coal fly ash toward methylene blue (MB), cadmium (Cd²⁺), and hexavalent chromium (Cr(VI)). Corn cob carbon was prepared via carbonization and KOH activation, while fly ash was calcined before composite preparation. SEM-EDS and BET analyses characterized the adsorbent’s physicochemical properties. KOH activation raised the corn cob carbon’s surface area from 8.80 to 40.88 m²/g, while calcination increased the fly ash’s surface area from 0.32 to 1.65 m²/g, indicating improved surface development. Under optimum conditions (5:1 fly ash-to-carbon ratio, 90-mesh particle size), the composite achieved removal efficiencies of 99.39% for MB (0.40 mg/g) and 99.56% for Cd²⁺ (1.659 mg/g), showing strong performance toward cationic pollutants. Cr(VI) removal, however, reached only 25.37% (1.723 mg/g), likely due to unfavorable electrostatic interactions between the adsorbent surface and anionic chromium species under the tested conditions. Overall, the composite showed promising adsorption performance for cationic contaminants, while further modification is needed to improve its effectiveness against anionic pollutants like Cr(VI).
Continuous Adsorption of and Cr (VI) Using a KOH-activated Corn Cob Carbon-Coal Fly Ash Composite Rony Sihombing; Alfiana Adhitasari; Shoerya Shoelarta; Tifa Paramitha; Ghaniari Putri; Khumaira Maulani Wijaya
Sainteknol : Jurnal Sains dan Teknologi Vol. 24 No. 2 (2026): December 2026 (In Press)
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v24i2.63139

Abstract

Industrial wastewater containing divalent cadmium (Cd₂⁺) and hexavalent chromium (Cr (VI)) poses a serious environmental threat because of the toxicity, persistence, and bioaccumulative nature of these heavy metals. This study aimed to evaluate the performance of a composite adsorbent, prepared from KOH-activated corn cob carbon (CCAC) and calcined coal fly ash (FA) at a mass ratio of 5:1, for the continuous adsorption of Cd₂⁺ and Cr (VI). The adsorbent was characterized using Fourier Transform Infrared (FTIR) spectroscopy, while continuous adsorption experiments were performed in an up-flow acrylic column at an initial metal concentration of 100 mg/L, evaluating the effect of flow rate (5–25 mL/min) on Cd₂⁺ removal and comparing it with Cr (VI) removal from real industrial wastewater at 5 mL/min. FTIR analysis confirmed that KOH activation and calcination modified the surface functional groups of the CCAC and FA, respectively, increasing the availability of oxygen-containing active sites. The composite adsorbent achieved a high and consistent Cd₂⁺ removal efficiency of 91.13–91.51%, with an adsorption capacity of 4.18–4.19 mg/g, across all tested flow rates. In contrast, Cr (VI) removal was very low (0.797%), attributed to electrostatic repulsion between the anionic Cr (VI) species and the negatively charged adsorbent surface at near-neutral pH, as well as competition from co-existing ions in the real wastewater matrix. These findings indicate that the FA/CCAC composite is a promising, low-cost, waste-derived adsorbent for continuous Cd₂⁺ removal, while further surface modification or pH adjustment is required to enhance its performance for Cr (VI) removal.
Study on the Effectiveness of H₂SO₄ Activated Coffee Grounds and Imperata cylindrica Bioadsorbents for Methylene Blue Adsorption Unung Leoanggraini; Tifa Paramitha; Rahma Ardelia Raissa; Mutiara Nur Annisa; Muhammad Salman Alfarisi; Radianti Novita Sari; Rony Sihombing
Sainteknol : Jurnal Sains dan Teknologi Vol. 24 No. `1 (2026): `June 2026
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v24i`1.63663

Abstract

Textile wastewater with methylene blue dye causes serious environmental issues because of its toxicity, persistence, and negative effects on aquatic life. Using agricultural waste as bioadsorbents provides a sustainable and low-cost way to remove dye from wastewater. The goal of this study was to assess how effective H₂SO₄-activated bioadsorbents made from coffee grounds and Imperata cylindrica are for methylene blue adsorption in batch systems. We prepared the bioadsorbents by carbonizing them at 450°C, followed by chemical activation with 2 M sulfuric acid. We characterized them using FTIR and SEM to study functional groups and surface shape. We conducted batch adsorption experiments by changing the adsorbent mass (0.15–0.3 g), contact time (30–120 minutes), and methylene blue concentration (10–100 mg/L). Langmuir and Freundlich isotherm models were used to evaluate the adsorption behavior. The results showed that activated coffee grounds and Imperata cylindrica had improved porosity and changes in functional groups after activation. The best adsorption conditions were found with an adsorbent mass of 0.3 g, a contact time of 120 minutes, and a methylene blue concentration of 10 mg/L, reaching an adsorption efficiency of up to 97.498%. The adsorption process fit the Langmuir isotherm model better, with maximum adsorption capacities of 42.735 mg/g for coffee grounds and 13.210 mg/g for Imperata cylindrica. These findings suggest that coffee grounds and Imperata cylindrica are promising, cost-effective bioadsorbents for removing methylene blue in textile wastewater treatment.
Co-Authors Alfiana Adhitasari Alfiana Adhitasari Ghaniari Putri Khumaira Maulani Wijaya Muhammad Salman Alfarisi Mutiara Nur Annisa Nurcahyo Paramitha, Tifa Radianti Novita Sari Rahma Ardelia Raissa Shoerya Shoelarta Unung Leoanggraini