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Sustainable magnetic biochar from agro-aquacultural waste for efficient Pb(II) and Cd(II) removal: Machine learning–assisted optimization and techno-economic evaluation
(2026-05-15)
Limmun, Wanida
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Limmun, Warunee
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Prangmoo, Yasumin
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Ishikawa, Nao
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Borkowski, John J.
This study presents the sustainable synthesis and optimization of magnetic biochar derived from agro-aquacultural waste, specifically rubber seed shells and oyster shells (MRO), for the efficient removal of Pb(II) and Cd(II) from aqueous solutions. MRO was synthesized via FeCl<inf>3</inf> activation and co-pyrolysis, enhancing adsorption capacity and magnetic recoverability. Process optimization was performed using Response Surface Methodology (RSM) and a Genetic Algorithm–Backpropagation Neural Network (GA–BPNN), with experimental validation confirming RSM-predicted conditions. The optimized MRO achieved high adsorption capacities of 709.99 mg/g for Pb(II) and 332.98 mg/g for Cd(II), following Langmuir and pseudo-second-order kinetic models. Mechanistic analysis identified surface complexation, ion exchange, electrostatic interaction, and precipitation as key pathways. MRO demonstrated excellent reusability, maintaining over 90% Pb(II) removal efficiency after 11 regeneration cycles. Techno-economic and environmental assessments revealed a low production cost (23 THB/kg), modest energy consumption (2.5 kWh/kg), and a reduced carbon footprint (0.50 kg CO<inf>2</inf>/kg). These results underscore the potential of MRO as a cost-effective and scalable adsorbent for sustainable wastewater treatment applications.
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Effect of heat pipe characteristics in the energy recovery ventilation system for positive pressure room
(2026-05-15)
Duangwana, Supaluek
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Chaiya, Wathanyu
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Laoariyawong, Anothai
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Chaimongkol, Jadsada
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Lapaphinya, Surasak
A system's high energy consumption is a drawback when it is used to create a positive pressure environment to reduce PM2.5. Air to air energy recovery ventilation systems (ERVs) using heat pipes are a feasible technology. This study aims to investigate the effect of installation patterns of heat pipes in air-to-air heat exchangers and the operating conditions of the system for generating a positive pressure environment. Flow characteristics of inline and staggered heat pipes with fins and without fins were investigated by using computational fluid dynamics. The different operating conditions varying inlet air temperature, air flow rate and heat pipe surface temperature were also studied. The results showed that the staggered heat pipes with fins introduced promising results. Outlet temperature was dominated by inlet air temperature and heat pipe surface temperature, while the pressure drop crossed ERV were relied on air flow rate. The promising results from the simulation were a guideline for constructing a practical heat exchanger that was integrated with positive pressure-generating equipment.
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Low-Cost Near-Infrared Spectroscopy for Rapid Prediction of Biodiesel Properties: Acid Value, Density, Viscosity, and Water Content
(2026-03-31)
Phetpan, Kittisak
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Thongphut, Chitwadee
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Chungcharoen, Thatchapol
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Limmun, Warunee
Partial least squares (PLS) regression, combined with various spectral pre-processing techniques, was employed to compare the performance of two diode array near-infrared (NIR) spectrometers in predicting key biodiesel quality parameters, including acidity, viscosity, density, and water content. An AvaSpec-Mini4096CL NIR spectrometer, operating within the 350–1100 nm wavelength range, was used as the representative shortwave near-infrared (SW-NIR) spectrometer, while a NIRQuest512 spectrometer, covering the 900–1700 nm range, was employed as the longwave near-infrared (LW-NIR) spectrometer. Both spectrometers were equipped with a transflection probe for spectral collection from oil palm-based biodiesel samples. The SW-NIR spectrometer outperformed the LW-NIR spectrometer. The optimal PLS models achieved root mean square errors of prediction (RMSEP) of 0.0037 mg KOH/g for acidity, 0.062 cSt (mm2/s) for viscosity, 2.67 kg/m3 for density, and 59.14 mg/kg for water content, highlighting the potential of compact SW-NIR spectrometers as effective, low-cost tools for rapid biodiesel quality monitoring.
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Sustainable Valorization of Salak Peel Waste: Regeneration of Biochar for Lead Removal from Wastewater
(2026-01-01)
Buakhiao, Phruektinai
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Chungcharoen, Thatchapol
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Jamkamon, Aud
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Limmun, Warunee
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Thungsotanon, Dithaporn
This study evaluates the effects of pyrolysis temperature (600°C and 800°C, denoted as SP600 and SP800) and regeneration reagents on lead (Pb²⁺) adsorption performance of biochar derived from salak peels. Moreover, the lead removal efficiency and adsorption efficiency after several regeneration cycles under appropriate conditions were also investigated. The results indicate that increasing the pyrolysis temperature significantly enhances lead removal efficiency and adsorption capacity, with biochar pyrolyzed at 800°C and loaded with lead (SP800Pb) exhibiting the highest initial lead adsorption performance. However, upon regeneration using hydrochloric acid (HCl) and sodium nitrate (NaNO₃) at various concentrations, SP600Pb demonstrated higher lead removal performance than SP800Pb across all conditions. Specifically, SP600Pb regenerated by 0.1M HCl exhibited the highest lead desorption efficiency and removal efficiency. Furthermore, after five consecutive adsorption-regeneration cycles, the biochar regenerated by 0.1M HCl (SP600RPb) exhibited a suitable removal efficiency of 83.91 ± 0.10 and a desorption efficiency of 148.73 ± 0.13. The observed desorption efficiency exceeding 100 was attributed to the accumulated release of Pb²⁺ ions during successive regeneration cycles, which indicates enhanced ion-exchange dynamics over time. Therefore, biochar pyrolyzed at 600°C and regenerated using 0.1M HCl is appropriate for the reuse of biochar in lead adsorption, promoting sustainable resource application, cost reduction, and waste minimization in production processes.
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Exploration demonstrates high yield and favorable characteristics of crude bio-oil derived by pyrolysis from natural rubber waste for applying as liquid biofuel and value-added product
(2026-01-01)
Palamanit, Arkom
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Ngampak, Supawich
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Ali, Liaqat
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Kongto, Pumin
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Chungcharoen, Thatchapol
Industrial processing of raw natural rubber (NR) and latex inevitably generates natural rubber waste. The aim of this study was to explore the yield and characteristics of crude bio-oil derived from industrial NR waste, with the goal of further upgrading it to liquid biofuel or other value-added products. Cup lump rubber (CLR) and skim rubber (SR) wastes were pyrolyzed at 400, 450, 500, and 550 °C for 45 min. The results show that pyrolysis of CLR and SR wastes provided crude bio-oils with good yield and very favorable characteristics. The maximum bio-oil yields from CLR and SR wastes were 83 wt.% and 80 wt.%, respectively, achieved at 450 °C. The pH and density of the bio-oil samples were in the ranges of 5.15–9.02 and 885–922.50 kg/m3. All the bio-oil samples had a very low water content (< 0.2 wt.%). High carbon and hydrogen contents in the bio-oils led to superior higher heating values (38.3–39.1 MJ/kg). Chemical compounds identified by GC-MS revealed a high content of D-Limonene (C<inf>10</inf>H<inf>16</inf>) at 36.16% in the bio-oil from CLR waste. These results are crucial for further upgrading the bio-oil from industrial CLR and SR wastes, to liquid biofuels or other value-added products.
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Investigation of physiological disorder classification in mangosteen fruit using visible and shortwave near-infrared spectroscopy combined with machine learning
(2025-12-01)
Ruttanadech, Nuttapong
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Momin, Abdul
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Phetpan, Kittisak
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Chaichanyut, Montree
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Thongphut, Chitwadee
Accurate classification of physiological disorders in mangosteen fruit is crucial for ensuring production quality, safety, sustainability, and economic viability. This study investigates the application of visible and shortwave near-infrared (Vis/SWNIR) reflectance spectroscopy, combined with machine learning algorithms, to classify three primary disorders: normal fruit (NF), translucent flesh disorder (TFD), and TFD with yellow gummy latex (TFD & YGL). The study specifically examines the effects of light intensity, spectral pretreatments, and machine learning models on classification performance. Spectral data were collected using two light intensities (50 % and 100 % of a 150 W light source) and processed with three pretreatments: standard normal variate (SNV), second derivative Savitzky-Golay (SGD2), and a combination of SNV and SGD2. Random forest (RF), support vector machine (SVM), and multi-layer perceptron (MLP) algorithms were used for classification. The SGD2 method improved differentiation, especially for the TFD & YGL class, in the 700–725 nm wavelength range, which is associated with xanthone content in the fruit's pericarp. Higher light intensity (100 %) significantly improved classification accuracy, achieving an overall accuracy of 0.71 and an average F1 score of 0.61 with the RF model. Despite these improvements, the model struggled to distinguish the TFD class from NF due to their similar spectral profiles. Overall, the Vis/SWNIR spectroscopy and machine learning combination shows strong potential for the non-destructive classification of mangosteen fruit disorders. Both light intensity and spectral pretreatments play critical roles in enhancing performance. Future studies should focus on improving spectral sensitivity to better capture internal fruit characteristics.
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Biodiesel Washing by the Prototype of a Biodiesel Washing Machine with Biochar
(2025-11-01)
Fonghiransiri, Surasak
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Chungcharoen, Thatchapol
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Choola-Aied, Orasa
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Srisang, Siriwan
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Srisang, Naruebodee
Currently, the prevalent technique for biodiesel washing entails the utilization of water in the purification process. Nevertheless, this method incurs substantial biodiesel loss and gives rise to wastewater, posing potential environmental consequences. Hence, this study aimed to utilize biochar for removing impurities from biodiesel by using a prototype of a biodiesel washing machine with biochar. The effects of the propeller blade number, propeller blade angle, and mixing time on the capability to eliminate impurities in biodiesel were elucidated. The results indicated that the biodiesel washing machine can increase biodiesel yield by up to 2.49% (91.54%) compared to the water washing process (89.05%). The increased propeller blade number, angle, and mixing time can improve the acidity (24.50-64.04%) and water content removal (42.61-79.56%). Consequently, this led to a decrease in density (865.85-886.83 kg/m3) and viscosity (3.997-4.321 cSt). The conditions with the best biodiesel properties were five propeller blades, a propeller blade angle of 60 degrees, and a mixing time of 30 minutes. These conditions provided the 63.88% acid removal, 79.49% water content removal, viscosity of 878.92 kg/m3 and density of 4.208 cSt. Moreover, the methanol and glycerol contents were 0.02% wt. and 0.04% wt., respectively. These properties meet the ASTM 6751 and EN 14214 biodiesel standards.
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Sustainable tropical fruit peel waste biochars for enhanced cadmium and lead adsorption: mechanistic insights and optimization using response surface methodology and backpropagation neural networks
(2025-08-01)
Limmun, Wanida
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Limmun, Warunee
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Maneesri, Wisit
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Pewpa, Orrawan
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Chungcharoen, Thatchapol
Heavy metal contamination, particularly from cadmium (Cd(II)) and lead (Pb(II)), presents a severe environmental challenge due to its toxicity and persistence. This study explores an innovative approach by utilizing abundant yet underutilized tropical fruit peel waste to produce biochars that serve as effective, sustainable adsorbents for heavy metal remediation. Biochars derived from banana peels (BP) and Monthong durian shells (DS) were synthesized via pyrolysis at 400–800 °C and evaluated for their physicochemical properties and adsorption efficiency. The DS600 biochar exhibited the highest adsorption capacity, removing Cd(II) (40.37 mg/g) and Pb(II) (51.74 mg/g), surpassing BP600 (40.22 mg/g and 47.23 mg/g, respectively). This study introduces a dual-modeling framework by integrating response surface methodology (RSM) with backpropagation neural network (BPNN) to optimize adsorption conditions and enhance predictive accuracy. The optimized conditions achieved over 99% removal efficiency, with R2 > 0.98 and MSE < 0.05, confirming the robustness of the model-based predictions. The study highlights the superior adsorption performance of DS600 biochar, with adsorption mechanisms influenced by pH, dosage, and biochar properties. In contrast to conventional studies that focus solely on equilibrium adsorption or rely on statistical models, this work pioneers the use of tropical fruit peel biochar in heavy metal remediation, providing quantitative insights into process optimization and practical scalability. The findings demonstrate the potential for valorizing agricultural waste into high-performance adsorbents, advancing cost-effective and sustainable water treatment technologies.
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Enhanced biodiesel purification using coffee husk bioadsorbents: The role of pyrolysis temperature, KOH activation, and adsorption efficiency
(2025-05-01)
Chungcharoen, Thatchapol
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Limmun, Warunee
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Srisang, Siriwan
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Phetpan, Kittisak
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Ruttanadech, Nuttapong
This study evaluates the performance of bioadsorbents derived from coffee husk pyrolyzed at temperatures of 600, 700, and 800 °C (CH600, CH700, and CH800), along with activated CH700 (ACH700), in biodiesel purification. The results indicate that CH700 significantly enhances biodiesel purity, with optimal purification conditions achieved at a dosage of 2 wt% CH700, a stirring rate of 400 rpm, and a contact time of 45 min. CH700 demonstrated modest performance, achieving approximately 20 % removal of methanol and water. However, after activation with potassium hydroxide (KOH), ACH700 demonstrated improved efficiency, achieving 96.92 % methanol removal and 39.46 % water removal. ACH700 also refined biodiesel quality to meet EN14214 standards and maintained a higher biodiesel yield compared to other adsorbents. The bioadsorption process is influenced by the chemical interactions between the surface functional groups of the bioadsorbent and the contaminants, which is further enhanced by the optimized pore structure of ACH700. The use of ACH700 represents a novel and highly effective approach to biodiesel purification, combining both technical efficiency and economic feasibility. Furthermore, the valorization of agricultural waste adds significant environmental benefits, reinforcing the potential of ACH700 for large-scale biodiesel production.
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Application of Centrifuge Combined with Biodiesel Washing Machine with Biochar in Biodiesel Production
(2025-01-01)
Fonghiransiri, Surasak
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Chungcharoen, Thatchapol
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Choola-aied, Orasa
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Limmun, Warunee
This research focused on the application of a centrifuge combined with a biodiesel washing machine with biochar in biodiesel production. This method aims to reduce the amount of biochar used in the washing process to meet biodiesel standards. Therefore, the research aimed to improve the biodiesel production process by using a centrifuge machine combined with the biochar washing method (CB) and comparing it with two methods: gravitational settling combined with water washing (GW) and gravitational settling combined with biochar washing (GB). The results indicated that the CB method could reduce contaminants in biodiesel. Although the biodiesel yield did not differ from the GB method, it remained higher than the GW method, increasing the biodiesel yield by up to 1.19% (90.24%). Furthermore, the CB method was more effective in removing acidity, water content, methanol, and glycerol in biodiesel compared to the GB method, with removal percentages of 63.88%, 79.49%, 99.70%, and 85.19% respectively. Consequently, this led to a decrease in viscosity (3.998 cSt) and density (865.93 kg/m3). This method provides biodiesel properties that meet biodiesel standards.

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