Despite the rapid development of electric vehicles, the shrinking number of fossil fuels that are the source of electricity remains conventional. The availability of energy sources and technology is sometimes naturally limited, high-priced, and might be politically circumscribed. This leads to an increased desirability of biodiesel due to its modest and economically higher energy density in comparison to batteries. The palm oil industry accounts for 23% of total deforestation in Indonesia. Contrary to palm oil, pangium edule (PE) is considered more sustainable and it intercrops with most of the forest’s vegetation while supplying biodiesel feedstock. A relatively higher pangium edule methyl ester (PEME) was delivered through PE feedstock, provided that it was processed with a heterogeneous catalyst, K2O/PKS-AC. This feedstock consumed a lower alcohol ratio and had a reasonably swift production process without sacrificing biodiesel quality. Therefore, this study aims to assess the performance of the PE biodiesel blend in a power generator. Furthermore, PEME was blended with diesel fuel in the variation of B0, B20, B30, B40, and B100. It was also tested with four-stroke single-cylinder diesel power generators to produce electricity. The B30 blend stands out in this experiment, achieving the highest engine power of 0.845 kW at a low load and dominating at a higher load with a minimum fuel consumption of 1.33 kg/h, the lowest BSFC of 0.243 kg/kWh, and second in BTE values at 21.16%. The result revealed that the main parameters, which include actual and specific fuel consumption, and the thermal efficiency of PE biodiesel performed satisfactorily. Although there was a slight decrease in the total power delivered, the overall performance was comparable to petroleum diesel.

This research focuses on optimizing fermentation modification and papain enzymes. In manufacturing virgin coconut oil using the response surface methodology (RSM), the experiment was carried out based on the Central Composite Design (CCD). Coconut oil yield, as a function of crude papain enzyme (CPE) mass (0–1 g) and fermentation time (12–60 h), was observed for 13 runs. The yield of virgin coconut oil with natural fermentation without the addition of crude enzyme papain is 19%, and with the addition of 1 g of the enzyme, it can reach a maximum of 27.7%. Optimal conditions were obtained at a mass of crude papain enzyme 993.5 mg, fermentation time 60 h respectively, yields: Banda Aceh virgin coconut oil (BAVCO) 28.4%, Pidie Jaya virgin coconut oil (PJVCO) 25.6%, and Bireuen virgin coconut oil (BVCO) 24.7%, quality of virgin coconut oil (VCO): water content (WC) 0.047%, free fatty acid (FFA) 0.01%, and peroxide (PN) 0.024% from each of the total mass of 300 g grated coconut, VCO modified by fermentation with the addition of CPE increased the yield. The quality of VCO in terms of WC, FFA, and PN meets the VCO quality standard. The optimization for desirability was 0.998, and the product had a transparent color, a distinct aroma, and did not have a putrid aroma.

Increasing CO₂ gas emissions results in climate change by increasing air temperature and worsening environmental problems. It is necessary to control CO₂ gas in the air to overcome this. This research aims to optimize the absorption of CO₂ gas in the air with 0.1 M NaOH absorbent in the column of the Raschig ring stuffing material using the response surface methodology (RSM). This research was conducted using a continuous system of three independent variables by varying the contact time (10–80 min), the flow rate of NaOH absorbent (2–5 L/min), and the flow rate of CO₂ gas (1–5 L/min). The response variables in this study were the absorption rate (L/min) and mass transfer coefficient, while the air flow rate was constant at 20 L/min. Air and CO₂ gas mix before absorption occurs and flow into the Raschig ring packing column so that contact occurs with the NaOH absorbent. Mass transfer of CO₂ gas occurs into the NaOH absorbent, resulting in absorption. The results showed that the effect of contact time (min), the flow rate of NaOH absorbent (L/min), and CO₂ gas flow rate individually and the interaction on CO₂ absorption rate and mass transfer coefficient were very significant at a p-value of 0.05. Chemical absorption of CO₂ also occurred due to the reaction between CO₂ and OH- to form CO₃²⁻ and HCO₃⁻, so the pH decreased, and the reaction was a function of pH. Optimization using Design Expert 13 RSM Box–Behnken Design (BBD) yielded optimal conditions at an absorption time of 80 min, NaOH absorbent flow rate of 5 L/min, CO₂ gas flow rate of 5 L/min, absorption rate of CO₂ gas of 3.97 L/min, and CO₂ gas mass transfer coefficient of 1.443 mol/min m² atm, with the desirability of 0.999 (≈100%).

The palm oil industry (POI) generates significant amounts of waste, including calcium carbonate (CaCO₃) from the clay bath system used for the separation of palm kernels from shells. This CaCO₃ waste is often discarded, leading to environmental issues. However, the CaCO₃ can potentially be reused in the clay bath separation process to improve efficiency and reduce waste. To obtain PKO, the kernel is separated from the palm shell using a clay bath unit, where natural CaCO₃ acts as a decanting agent and adsorbent. This wet separation method, involving a mixture of water and CaCO₃ with a density of 1.12 g/mL, generates substantial amounts of saturated CaCO₃ waste that is often discarded into the environment. Therefore, this research aimed to regenerate oil-bound CaCO₃ waste for reuse as a decanter and adsorbent. Three treatments were tested, with CaCO₃ waste-to-water ratios of 1:1, 1:3, and 1:6, under varying pH levels (8, 10, 11, 12) and temperatures (28 °C, 80 °C, 100 °C). The regeneration process was conducted in an open reactor at 450 rpm with a volume of 0.0054 m³, followed by drying and grinding the waste for analysis. The results showed approximately 75.75% oil removal and CaCO₃ regeneration rates between 94.50% and 99.26%, with an increase in density from 1.687 g/mL to 2.467 g/mL. The efficiency of reusing regenerated CaCO₃ waste is 96.87%. When mixed with 25% natural CaCO₃, the efficiency increases to 99.24%. Additionally, a mixture of 50% regenerated CaCO₃ waste and 50% natural CaCO₃ achieves an average efficiency of 99.46% over five consecutive feed additions. This showed that the reuse of CaCO₃ waste regeneration results for the separation of palm shells and kernels has a high potential for application. These findings suggest that regenerated CaCO₃ waste can be effectively reused, offering a sustainable solution for palm oil mills.