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Coffee tree trunks are a low-demand biomass resource with potential to be converted into higher-value products, such as charcoal briquettes. This study investigates the effect of drying temperature and particle size (Mesh 30 and Mesh 250) on the performance of coffee wood charcoal briquettes using starch as a binder. Drying was conducted at temperatures of 60°C, 80°C, and 100°C. The briquettes were tested through combustion by heating 50 ml of water, while temperature changes were recorded every minute using a thermocouple until boiling point was reached. Additional analyses included moisture content, ash content, combustion rate, and calorific value.The results show that higher drying temperatures improve briquette performance. The highest combustion rate for Mesh 30 was 0.20 g/min at 100°C, while Mesh 250 reached 0.16 g/min at the same temperature. The calorific value increased with temperature, with Mesh 30 reaching 7178.02 cal/g and Mesh 250 achieving 7498.80 cal/g at 100°C. Although Mesh 30 briquettes exhibited competitive calorific values, their combustion stability was lower compared to Mesh 250.These findings indicate that drying temperature and particle size significantly influence the quality and performance of coffee wood charcoal briquettes

One of the promising renewable energy sources is biomass, particularly underutilized candlenut shells, which can be processed into briquettes as a superior alternative to charcoal. This study aimed to utilize candlenut shell waste for briquette production, evaluating hardness and calorific value under varying carbonization temperatures (400°C, 500°C, 600°C) and mesh sizes (30 and 100). Briquettes were produced via carbonization and compression. Hardness was measured using a durometer, yielding the highest value of 76.33 HA at 600°C and 100 mesh, and the lowest of 43.58 HA at 400°C and 30 mesh. Calorific value, determined by bomb calorimetry, peaked at 7834.70 cal/g for 500°C and 30 mesh, while the lowest was 5085.24 cal/g at 500°C and 100 mesh. These results demonstrate that optimized carbonization and particle size enhance briquette quality, promoting sustainable biomass utilization for energy applications.

Lead (Pb²⁺) contamination in wastewater is a major environmental concern due to its toxicity, persistence, and ability to accumulate in living organisms. Adsorption using biomass-based materials has been developed as an alternative treatment method because it is efficient, economical, and environmentally friendly. This study aimed to analyze the effect of bioadsorbent dosage and contact time on Pb²⁺ removal efficiency and evaluate Pb²⁺ mass distribution using mass balance analysis in a batch adsorption system. Ramie leaf (Boehmeria nivea) was utilized as a bioadsorbent due to its lignocellulosic content, which provides active sites for metal ion adsorption. The research was conducted experimentally through bioadsorbent preparation, chemical activation, and batch adsorption using artificial Pb²⁺ solutions with variations in bioadsorbent dosage and contact time. Pb²⁺ concentrations before and after adsorption were analyzed using Atomic Absorption Spectroscopy (AAS). The obtained data were used to determine removal efficiency and Pb²⁺ distribution between the liquid phase and bioadsorbent. The results showed that ramie leaf bioadsorbent effectively reduced Pb²⁺ concentration, with the optimum condition obtained at 4 g/L bioadsorbent dosage and 90 minutes contact time, achieving 98.46% removal efficiency. Mass balance analysis indicated that Pb²⁺ ions were successfully transferred from the solution phase onto the bioadsorbent surface. These findings demonstrate that ramie leaf bioadsorbent has potential as a sustainable alternative material for heavy metal removal in wastewater treatment.

Odot grass (Pennisetum purpureum cv. Mott) is an important ruminant forage because of its high palatability, adaptability to tropical environments, and potential for high biomass production. This study aimed to evaluate the effect of solid organic fertilizer on the growth and production of odot grass as a basis for developing productive and sustainable forage cultivation. The experiment was conducted in Pangi Village, Dulupi District, Boalemo Regency, from February to March 2026 using a completely randomized design with five treatments and three replications. The treatments consisted of P0 without solid organic fertilizer, P1 at 10 t/ha, P2 at 20 t/ha, P3 at 30 t/ha, and P4 at 40 t/ha. Observed variables included plant height, leaf number, tiller number, and fresh weight production. Data were analyzed using analysis of variance followed by Duncan’s multiple range test at the 5% significance level. The results showed that P4 produced the best response for all measured parameters. The highest plant height was 77.83 ± 43.80 cm, with 18.83 ± 3.67 leaves, 2.42 ± 1.38 tillers, and fresh weight production of 52.33 ± 10.12 t/ha. These improvements indicate that 40 t/ha solid organic fertilizer enhanced nutrient availability and supported biomass formation. Solid organic fertilizer is therefore a promising locally based cultivation input for improving ruminant forage productivity.

Sweet corn (Zea mays saccharata Sturt.) is an increasingly popular horticultural commodity in Indonesia, attracting both farmers and consumer. This study aims to evaluate the effectiveness of single‑micronutrient fertilizer Mn‑EDTA (12%) in enhancing the growth and yield of sweet corn (Zea mays saccharata Sturt.). The treatments consisted of control, standard NPK, 0.25 NPK, 0.50 NPK, 0.75 NPK, and 1.00 NPK. The experimental findings demonstrated that the application of single‑micronutrient Mn‑EDTA (12%) fertilizer had a highly significant effect on vegetative growth and yield components of sweet corn, with statistically higher values compared with the control treatment. In general, fertilizer dosages equivalent to 0.25–1.00 NPK produced greater plant height, stem diameter, leaf number, ear length, ear diameter, biomass weight, ear weight with husk, ear weight without husk, plot yield, and productivity than the control. The RAE calculation indicated that the fertilizer was effective when applied at dosages equivalent to 0.75 and 1.00 NPK. The highest effectiveness was observed at the 1.00 NPK dosage, with an RAE value of 101%. Notably, the application of Mn‑EDTA (12%) fertilizer at the 1.00 NPK dosage provided significant field effectiveness, as reflected by the RAE value of 101%. This result implies that the use of single‑micronutrient Mn‑EDTA (12%) fertilizer at the 1.00 NPK dosage increased yield by 1.01 times compared with the yield improvement obtained from the reference fertilizer relative to the control treatment.

This study aims to analyze the development of studies on the use of biomass as a renewable energy source to support national energy security using a bibliometric approach. Research data were obtained from the Scopus, Web of Science, and Google Scholar databases with a publication range of 2015-2025. The analysis was conducted using VOSviewer and Biblioshiny. The results show a significant increase in publication trends in the last decade, especially in the period 2016-2024, reflecting the increasing academic attention to biomass as a solution in the energy transition. Keyword visualization shows that biomass is closely related to concepts such as combustion, thermal efficiency, calorific value, and pelletizing. China is the country with the highest publication contribution, while Indonesia is strategically positioned due to its abundant biomass waste potential. Overall, biomass has great potential to support energy diversification, reduce dependence on fossil fuels, and strengthen national energy security in a sustainable manner.

Coal mining activities in East Kalimantan have significantly contributed to regional economic development, but they have also resulted in extensive land degradation that requires effective reclamation strategies. The integration of forage crops in reclaimed mine lands offers an opportunity to simultaneously support ecological restoration and livestock production. However, the performance of forage grasses under shaded conditions created by revegetation trees remains insufficiently understood. This study aimed to evaluate the physiological responses, morphological characteristics, and nutritional quality of two forage grass species, Brachiaria humidicola and Stenotaphrum secundatum, grown under shaded conditions on reclaimed coal mine land. The experiment was conducted at the PT Kitadin Embalut reclamation site, East Kalimantan, using a split-plot design with two shading levels (0% and 50%) as the main plots and two grass species as subplots. Each treatment was replicated six times. Variables measured included dry matter yield, leaf-to-stem ratio, chlorophyll content (a, b, and total), crude protein, and crude fiber content. The results showed that a 50% shading level significantly influenced physiological and morphological responses of the grasses. Stenotaphrum secundatum exhibited a marked increase in chlorophyll content under shaded conditions, indicating a stronger acclimation to low light environments compared with Brachiaria humidicola. Shading also reduced the leaf-to-stem ratio in both species. However, dry matter production was not significantly affected by shading, suggesting that both grasses were able to maintain biomass accumulation under moderate shade conditions. Shading slightly reduced crude protein and crude fiber contents.

Pyrolysis is a biomass conversion method into fuel through heating at high temperatures under oxygen-limited conditions. The main factors influencing the pyrolysis process include temperature, residence time, pressure, particle size, reactor design, and the type of pyrolysis employed. This study aims to design an auger-type fast pyrolysis system based on previous research. The design and modeling of the fast pyrolysis equipment were carried out using Autodesk Inventor 2021 software. Based on the calculation and design results, a fast pyrolysis reactor with a multi-stage configuration and a capacity of 5.2 kg was developed. The system consists of a three-stage reactor made of Stainless Steel 304. The reactor is equipped with a screw conveyor for material transport, which is driven by an electric motor. Biomass heating inside the reactor is provided by a clamp heater with an electrical power requirement of 611 W, while biomass cooling is performed using a condenser with a cooling water capacity of 15.586 liters. Based on the structural simulation results, the maximum von Mises stress obtained was 35.4 MPa, the maximum displacement was 0.0528 mm, and the safety factor was 6.07 under loading conditions including an internal reactor pressure of 0.32 MPa, a torsional moment of 1,130 kg·mm, and an operating temperature of 700 °C. These values are within the allowable limits of the material, indicating that the designed reactor is structurally safe and feasible for use.

Coffee husk is an agro-industrial waste with significant potential to be utilized as a renewable energy source through the fast pyrolysis process. This study aims to analyze and optimize gas production from the fast pyrolysis of coffee husk biomass using a screw reactor through single-particle-based Computational Fluid Dynamics (CFD) simulations. The simulations were conducted by varying the operating temperature at 500°C, 600°C, and 700°C to examine pressure distribution, heat transfer, particle temperature, and the formation of pyrolysis products, namely bio-oil, biogas, and biochar. The modeling was performed using COMSOL Multiphysics 6.2 with a numerical approach to represent thermal phenomena and biomass decomposition reactions during the pyrolysis process. The simulation results indicate that increasing temperature significantly affects the rate of heat transfer and the temperature distribution of coffee husk particles. At 600°C, heat transfer and temperature distribution are more uniform compared to 500°C, although heating at the particle core is not yet fully optimal. The pressure distribution shows a stable flow of pyrolysis gas from the bottom to the top of the reactor. In terms of products, increasing temperature leads to a reduction in biochar and bio-oil formation due to the occurrence of secondary reactions, while biogas production increases. The highest gas production is achieved at 700°C, indicating the most optimal condition for maximizing gas yield from fast pyrolysis. Therefore, single-particle-based CFD simulation can be used as an effective tool to understand pyrolysis mechanisms and optimize process parameters in a screw reactor.

This study investigates biomass-derived surface engineering of AISI 1020 steel for electromedical applications using galam wood charcoal and chicken bone waste as carburizing media. Surface modification is required to improve the mechanical performance of low-carbon steel, particularly in applications that demand high wear resistance and long-term durability. A pack carburizing approach was applied using various ratios of biomass-derived media at a treatment temperature of 800 °C for 2 hours. Chemical composition was analyzed using Optical Emission Spectroscopy (OES), surface hardness was evaluated using Micro Vickers hardness testing, and microstructural characteristics were observed using optical microscopy. The results show a significant increase in surface carbon content with increasing fractions of chicken bone powder, indicating its effectiveness as a carbon donor and diffusion promoter. The surface hardness increased from approximately 150 HV in the untreated condition to a maximum of about 860 HV in the treated specimen. Microstructural observations revealed the formation of a distinct carburized layer with increasing thickness and uniformity, consistent with enhanced carbon diffusion and surface strengthening. These findings demonstrate that biomass-derived surface engineering provides an effective and sustainable approach for improving the surface properties of low-carbon steel. The proposed method offers strong potential for environmentally friendly manufacturing of durable and reliable electromedical components.

The increasing need for insulation in electric power systems encourages the discovery of high-performance and sustainable dielectric materials. This study presents a Literature Review of biomass-based composite insulator research from 2018-2025 to synthesize the effect of filler type and treatment on the electrical, thermal, and mechanical properties of polymer composites. Literature was analyzed from reputable databases with inclusion criteria, and thematic analysis data extraction. Processing methods generally include washing, acid/alkali treatment, calcination, and advanced production techniques such as sol-gel and ultrasonication, integration of biomass fillers especially at low fractions (3-7%). The results show 1) the dominance of the use of rice husk as a source of biosilica for the main matrix filler of the insulator. 2) the performance of biomass composite insulators is highly dependent on the quality of purification, particle size, and surface modification of the filler. 3) there is a significant increase in the insulator's breakdown strength, resistivity, and thermal stability with the addition of biomass fillers to the main matrix. 4) the long-term stability of biomass materials against humidity and thermal aging has not been evaluated in depth.  

Proton Exchange Membrane Fuel Cells (PEMFCs) are increasingly developed due to their high efficiency, power density, durability, and environmental friendliness. However, the high cost of platinum catalysts limits their widespread application. Reducing platinum usage through the development of low-cost catalyst support materials is a promising approach. Activated carbon derived from biomass offers a sustainable and economical alternative, particularly when utilizing agricultural waste such as coffee husks, which are often discarded. This study aims to evaluate the characteristics of activated carbon produced from coffee husk waste through pyrolysis as a catalyst support for PEMFCs. Pyrolysis was conducted at 400 °C, followed by chemical activation using 1 M H₃PO₄ and 1 M KOH with a residence time of 90 minutes. The resulting activated carbon was analyzed through proximate analysis to determine moisture content, ash content, volatile matter, and fixed carbon content. The results showed that activation with 1 M H₃PO₄ produced the lowest moisture content (3.4%), the lowest ash content (3.8%), and the highest fixed carbon content (60.5%), while 1 M KOH yielded the lowest volatile matter content (27.7%). Based on these results, activated carbon produced using H₃PO₄ meets the requirements of SNI No. 01/6235/2000 and demonstrates strong potential as a catalyst support material for PEMFC applications.

Increasing in energy demand and limited fossil fuel reserves have driven the use of environmentally friendly alternative energy sources. This study aims to analyze the effect of pyrolysis temperature variations on the quality of biopellets made from bagasse and coffee husks. The materials were prepared in a 50:50 ratio with the addition of 15% tapioca flour as a binder. The pyrolysis process was carried out at temperatures of 450°C, 500°C, and 550°C for 120 minutes in oxygen-free conditions. The biochar resulting from pyrolysis was formed into biopellets, which were then tested for proximate composition, calorific value, and combustion rate. The results showed that an increase in pyrolysis temperature had a significant effect on the characteristics of the biopellets. A temperature of 550°C produced the lowest moisture content (8.436%), the highest fixed carbon content (62.191%), the highest calorific value (6293 cal/g), and the highest combustion rate (0.05789 g/sec). Conversely, ash content increased with rising temperature, while volatile matter content decreased. Thus, the best biopellets were obtained at a temperature of 550°C. This study confirms the potential of bagasse and coffee husks as raw materials for biopellets through pyrolysis temperature optimization to support the development of sustainable biomass energy.

This study comprehensively evaluates the quality of biomass briquettes produced from blends of coconut shell charcoal and sengon sawdust, using both carbonized and non-carbonized materials. Composite briquettes were fabricated with varying compositions and characterized through proximate analysis, calorific value, density, and burning rate measurements to determine their suitability as solid fuel. The results indicate that adding non-carbonized sawdust increases volatile matter content and burning rate but reduces the calorific value of the briquettes. In contrast, incorporating up to 10% carbonized sawdust significantly improves the calorific value to 6119.2 cal/g, approaching that of pure coconut shell charcoal (6352.2 cal/g), while maintaining a relatively high burning rate. Briquettes containing carbonized sawdust also exhibit low ash content, below 3%, and moisture content under 8%, meeting standard solid fuel quality requirements. These findings demonstrate that a strategic combination of carbonized and non-carbonized materials can produce hybrid biomass briquettes with optimized thermal performance, providing a promising, sustainable, and environmentally friendly alternative fuel for domestic and industrial applications.

This study aims to determine the ideal stocking density of catfish using the triple integral method. This mathematical method is applied to accurately calculate the volume of the cultivation pond and analyze the stocking amount and biomass projection at three different density levels, namely 50, 75, and 100 fish/m³. The calculation of the volume of the pond measuring 27 m x 11 m x 1.5 m produces a value of 445.5 m³. Based on the integral calculation, the optimal stocking amount is 22,275 fish, 33,413 fish, and 44,550 fish for each density, with the final biomass projection reaching 300.7 kg, 451.1 kg, and 600.4 kg, respectively. The analysis shows that the density of 100 fish/m³ produces the highest biomass, but its application must consider technical factors such as water quality, oxygen availability, and food competition. This method provides a solid and practical mathematical foundation for more efficient, scalable, and sustainable aquaculture planning.

Sweet corn is a horticultural commodity that is widely consumed in Indonesia. This study evaluated the effectiveness of NPK 18-18-18 fertilizer on the vegetative growth, yield components, and relative agronomic effectiveness (RAE) of sweet corn (Zea mays saccharata). Field experiments were conducted using fertilizer dosages of 0,50, 0,75, 1,00, and 1,50 NPK, with a control treatment for comparison. The application of NPK 18-18-18 significantly increased plant height, stem diameter, leaf number, ear length, ear diameter, biomass weight, ear weight with husk, ear weight without husk, plot yield, and overall productivity compared with the control. Mean values across treatments ranged from 68,94–205,72 cm for plant height, 7,41–20,47 mm for stem diameter, 6,01–13,00 leaves per plant, 15,41–20,89 cm for ear length, and 36,05–49,65 mm for ear diameter. Biomass weight ranged from 0,12–0,34 kg, ear weight with husk from 0,13–0,34 kg, and ear weight without husk from 0,12–0,28 kg. Plot yield varied between 7,91–25,46 kg, corresponding to productivity levels of 5,02–16,16 t/ha. RAE analysis indicated that fertilizer application was effective at dosages of 0,75, 1,00, and 1,50 NPK, with the highest effectiveness observed at 1,50 NPK (118%). Notably, the 0,75 NPK dosage achieved an RAE value of 101%, demonstrating that lower fertilizer input can enhance yield while reducing production costs and mitigating fertilizer scarcity. These findings suggest that NPK 18-18-18 fertilizer, when applied at an optimal dosage, can be effectively utilized in sweet corn cultivation to improve growth and productivity while ensuring efficient nutrient management.

Biomass as a renewable energy source holds immense potential and is applicable across various industrial sectors, being both renewable and sustainable. Renewable energy derived from biomass is widely recognized as one of the most significant energy alternatives due to its environmental friendliness, as it originates from living organisms and has the capacity and availability to serve as a future energy source. This research aims to identify the development of research on biomass as an energy source, specifically in Indonesia, using the Systematic Literature Review (SLR) technique guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. SLR, which follows standardized rules for identifying and synthesizing relevant studies, provides a comprehensive understanding of the topic's current knowledge base. Data were collected from journals using the Publish or Perish application; an initial search of the Google Scholar database yielded 1600 articles, which were rigorously screened, resulting in 1508 exclusions and 92 inclusions for thorough analysis. Ultimately, this SLR method effectively demonstrates the development of research concerning biomass as a renewable energy source.

Zinc (Zn) is one of the most common heavy metal contaminants found in industrial wastewater and solid residues such as slag, electroplating waste, and metal ash. At excessive concentrations, Zn can cause environmental disturbances, including toxicity to aquatic organisms, disruption of microbial activity, and groundwater contamination. Long-term exposure may also lead to bioaccumulation and potential health risks to humans. This article presents a comprehensive literature review that discusses the chemical properties of Zn, its environmental behavior, and the development of recent treatment technologies within the last five years. Several techniques, including adsorption using modified or composite materials, biosorption utilizing microalgae and agricultural biomass, as well as solidification–stabilization with amendment agents such as biochar or iron-sulfide compounds, are evaluated and compared. The literature indicates that no single treatment method is universally effective for all waste types; therefore, hybrid or integrated treatment systems are considered more efficient and sustainable. Based on the reviewed evidence, this study proposes an engineering concept that emphasizes environmental safety, cost-effectiveness, and industrial applicability.

Beetroot is traditionally cultivated in highland areas; however, limited land availability and growing market demand have encouraged its expansion into mid-altitude regions. Thermal unit accumulation is an important factor in predicting crop phenology and harvest time. This study aimed to analyze the thermal unit requirements, growth performance, and tuber quality of beetroot cultivated at different altitudes in East Java, Indonesia. The experiment was conducted from August to December 2024 in greenhouses located in Jatimulyo, Malang (445 m a.s.l., midland) and Sumberejo, Batu (873 m a.s.l., highland) using 250 plants of the Boro variety with a single-plant observation method. Results showed that midland-grown plants reached harvest earlier (84 DAS; 1,527.3 °C·day) compared to highland-grown plants (104 DAS; 1,572.7 °C·day). Higher thermal accumulation had a strong positive correlation with soluble solids (r = 0.74) and a strong negative correlation with fresh tuber weight (r = –0.79), indicating that increased heat enhanced sugar synthesis but reduced biomass. Highland conditions produced larger tubers, while midland conditions improved betacyanin and sweetness levels, showed that altitude-driven temperature differences affect both yield and quality, suggesting that highland cultivation is suitable for fresh markets, whereas midland cultivation is more appropriate for industrial uses such as natural food colorants and processing industries.

Waste candlenut shells are one type of biomass that has significant potential to be developed as an alternative energy source, particularly in the form of briquettes. Candlenut shells, which are typically discarded as agricultural waste, contain combustible material that can be transformed into solid fuel. However, the traditional briquette molding process is still done manually, which is time-consuming, inefficient, and often results in inconsistent briquette shapes and density. This study aims to design and develop a briquette molding machine specifically for processing candlenut shell waste, with the goal of improving both production efficiency and the quality of the briquettes produced. The research methodology includes several stages: mechanical design, selection of appropriate materials, fabrication of machine components, assembly, and performance testing of the machine. The resulting machine utilizes a screw conveyor compression system powered by a 5.5 HP petrol engine. It features a cylindrical mold with a 40 mm diameter to shape the briquettes uniformly. During the performance test, the machine demonstrated a maximum production capacity of 14.3 kg per hour, with an average processing time of 24 minutes and a briquette yield reaching up to 85%. The findings indicate that the machine can significantly streamline the briquette production process while maintaining product consistency and quality. This briquette molding machine is particularly suitable for household and small-scale industries aiming to utilize renewable energy sources and reduce dependency on fossil fuels. The use of this machine also supports environmental sustainability by converting agricultural waste into a usable energy product.