MOTIVECTION : Journal of Mechanical, Electrical and Industrial Engineering

The Effect of Activated Carbon From Palm Oil Kernel Shells on Waste Cooking Oil for Soap Production

Wed, 18 Feb 2026 00:00:00 +0000

This study addresses the existing limitation in integrated waste valorization approaches by combining palm kernel shell–derived activated carbon production, waste cooking oil purification, and solid soap manufacturing within a UMKM-based circular economy model. Unlike previous studies that focus separately on adsorbent synthesis or oil purification, this research evaluates the adsorption performance quantitatively and links it directly to downstream soap quality. Activated carbon was synthesized via controlled pyrolysis (400 °C) followed by KOH activation (800 °C) and characterized using FTIR. The purification process reduced free fatty acid (FFA) content from 2.35 ± 0.02% to 0.43 ± 0.01%, corresponding to an adsorption efficiency of 81.7%. The adsorption capacity was calculated and statistical validation was performed in triplicate experiments. The resulting solid soap exhibited stable pH (8.89 ± 0.05) and satisfactory physical properties. These findings demonstrate the scientific and practical contribution of palm kernel shell activated carbon as a sustainable bioadsorbent supporting circular economy implementation at the UMKM scale.

Determination of Optimal Route for Distribution of Rice Food Assistance in City X using the Cuckoo Search Algorithm

Eri Wirdianto, Muhamad Gustaffo Bintang, Farhan Azhari — Mon, 02 Mar 2026 03:25:57 +0000

As distribution requirements become more complex, various VRP variants have been developed to address specific challenges. Among them, the Vehicle Routing Problem with Time Windows (VRPTW) adds the constraint that each customer must be served within a predefined time frame, making the routing process considerably more difficult. In this study, we propose a new approach that uses the Cuckoo Search (CS), a metaheuristic algorithm based on Lévy flights. This combination of Lévy flights and CS is designed to maximize exploration of optimal solutions while allowing dynamic route variations. This study aims to evaluate the effectiveness of this approach in optimizing rice food assistance distribution routes in City X. The exact method yielded a global optimum solution consisting of four routes with a minimum total distance of 222 km, requiring 2 hours 36 minutes 27 seconds of computation. In comparison, the cuckoo search algorithm also produced four routes, with a slightly longer total distance of 244 km but a significantly shorter computation time of 1 minute 39 seconds. This represents a difference of about 22 km (9.91%) from the exact solution, demonstrating that for VRPTW, the cuckoo search algorithm can generate near-optimal results with minimal deviation and substantially reduced computational effort.

Evaluation of the Stability of the Anaerobic Digestion Process of POME Based on the Correlation of VFA, Alkalinity and Methane Content

Thu, 05 Mar 2026 00:00:00 +0000

Palm Oil Mill Effluent (POME) contains a high organic load and requires effective treatment to prevent environmental pollution while enabling energy recovery. Anaerobic digestion is widely applied for POME treatment due to its ability to reduce organic pollutants and produce methane-rich biogas; however, its performance is highly dependent on process stability. This study aims to evaluate the stability of the anaerobic digestion process of POME through correlation analysis among volatile fatty acids (VFA), total alkalinity (TA), suspended solids (SS), and methane content (CH₄) using field operational data. The study was conducted at an industrial-scale biogas plant treating POME, where slurry samples were collected periodically from multiple biodigester units representing different digestion stages. VFA and TA were analyzed using acid–base titration, SS by gravimetric method, and methane content using a gas analyzer. The results show that the anaerobic digestion process operated under stable mesophilic conditions (35 ± 2 °C) with reactor pH maintained in the optimal range of 6.8–7.5. VFA concentrations remained relatively low (approximately 480–510 mg/L), supported by sufficient alkalinity (about 5,600 mg/L as CaCO₃), resulting in a low VFA/TA ratio (~0.09), indicating stable process conditions. A significant reduction in COD from approximately 41,700 ppm in the influent to about 7,200 ppm in the effluent was achieved, corresponding to a COD removal efficiency of 83%. Methane content in the biogas remained stable at ≥55%, supporting effective energy utilization without flaring. These results demonstrate that maintaining a balanced relationship among VFA, alkalinity, suspended solids, and operating conditions is essential for ensuring stable anaerobic digestion and consistent biogas quality in industrial-scale POME treatment systems.