Limmun, Warunee

Preferred name

Limmun, Warunee

Alternative Name

Limmun, W.

Main Affiliation

KMITL Prince of Chumphon Campus

warunee.li@kmitl.ac.th

Now showing 1 - 10 of 23

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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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Comparative Analysis of Biochar Properties from Lemon and Kumquat Peels at Different Pyrolysis Temperatures
(2025-01-01)
Limmun, Wanida
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Limmun, Warunee
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Ito, Ayumi
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Choolaaied, Orasa
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Phanchindawan, Naree
This study examines the effects of pyrolysis temperatures (500 °C and 700 °C) on the properties of biochar derived from lemon peel (LB), kumquat peel (KB), and their combination (LKB). The study analyzed the variations in biochar yield, elemental composition, and specific surface area. The results indicated that higher temperatures led to a reduction in yield but a significant improvement in specific surface area, pore volume, and carbonization, ultimately producing more stable and aromatic biochar. Additionally, LB700 and KB700 exhibited more developed pore structures and higher specific surface areas than those produced at 500 °C. Elemental analysis showed an increase in carbon content and a decrease in hydrogen content at elevated temperatures, suggesting improved biochar stability. These findings demonstrate that higher pyrolysis temperatures enhance the specific surface area and carbon content of biochar, making it more suitable for environmental applications such as soil quality improvement and pollutant adsorption. The study highlights the potential of using commonly discarded agricultural waste, such as lemon and kumquat peels, for biochar production.
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Exploration of an efficient method for removing antibiotics from water and digested sewage sludge using Fe(VI): Kinetics and P phytoavailability and compostability in treated sludge
(2023-09-01)
Limmun, Warunee
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Ishikawa, Nao
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Maeda, Takeki
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Umeda, Takayuki
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Song, Jie
Potassium ferrate (K<inf>2</inf>FeO<inf>4</inf>) containing hexavalent iron [Fe(VI)] is an environmentally friendly oxidant, which possesses strong oxidizing power to treat wastewater and sludge. Therefore, the present study investigated degradation of selected antibiotics, namely levofloxacin (LEV), ciprofloxacin (CIP), oxytetracycline (OTC), and azithromycin (AZI), in water and anaerobically digested sewage sludge samples using Fe(VI). The effects of different Fe(VI) concentrations and initial pH values on antibiotic removal efficiency were evaluated. Under the studied conditions, LEV and CIP were almost completely removed from water samples, following second-order kinetics. In addition, over 60% of the four selected antibiotics were removed from sludge samples using 1 g L−1 Fe(VI). Furthermore, P phytoavailability and compostability of Fe(VI)-treated sludge were evaluated using different extraction reagents and a small composting unit. The extraction efficiency of phytoavailable P using 2% citric acid and neutral ammonium citrate was approximately 40% and 70%, respectively. The mixture of Fe(VI)-treated sludge and rice husk was self-heated in a closed composting reactor through the biodegradation of organic matter derived from the treated sludge. Therefore, Fe(VI)-treated sludge may be used as an organic material containing phytoavailable P for compost.
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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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Water-spray washing technique as a purification process in the production of biodiesel
(2020-09-08)
Limmun, Warunee
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Sansiribhan, Sansanee
In order to meet the standards set for biodiesel after biodiesel production via transesterification, a purification process is necessary. For the purification process, the wet washing method is mostly recommended because it is well-known for its easy application and high efficiency. However, this method requires a large volume of water and takes a long time. Consequently, this study focuses on designing a washing machine that reduces the amount of water used and shortens the application time for the washing method. The spray washing technique, a type of the wet washing method, was used for this study with a focus on the following parameters: The volume of water to crude biodiesel, flow rate, and time. All conditions investigated in the basic standards of biodiesel. The pH value, density, and velocity were considered as the criteria to select the optimum conditions for the washing machine. The results indicated that a volume ratio of 0.8:1 (water:crude biodiesel) and a flow rate of 4 L/min for 0.5 min was the optimum condition of the water washing machine for biodiesel purification that meets the international biodiesel specifications.
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Eco-friendly magnetic biochar from Leb Mu Nang banana peel: Response surface methodology optimization for Cd(II) adsorption from synthetic wastewater
(2024-02-01)
Limmun, Wanida
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Limmun, Warunee
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Borkowski, John J.
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Ishikawa, Nao
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Pairintra, Rattanachai
Magnetic biochar derived from Leb Mu Nang banana peel waste is introduced as a novel precursor for Cd(II) removal from synthetic wastewater. This study comprehensively evaluates and optimizes variable factors, including initial Cd(II) concentration, magnetic biochar (MLP) dosage, adsorption time, and initial pH level, using the Response Surface Methodology (RSM). A Cd(II) removal efficiency of up to 93.4 % is reached under the conditions of a 50 mg/L initial concentration, 5 g/L MLP dosage, 24 h of adsorption time, and a solution pH of 8. The pseudo-second-order and Langmuir models accurately represent the kinetics and isotherm adsorptions, highlighting ion exchange, surface complexation, and precipitation as primary adsorption mechanisms. The magnetic biochar derived from Leb Mu Nang banana peels shows promise for efficient Cd(II) removal with easy post-adsorption separation.
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Effects of Coffee Form and Distributor Hole Angle on The Fluidization Behavior and Specific Energy Consumption in The Fluidized Bed Machine
(2021-08-01)
Chungcharoen, Thatchapol
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Limmun, Warunee
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Sansiribhan, Sansanee
The fluidized bed technique was applied to use with the Robusta coffee in this research. fluidization behavior and specific energy consumption were investigated under various coffee forms and distributor hole angles. Moreover, the minimum fluidization velocity (Vmf) was also determined. Experiments are carried out in a sample bed height of 5 cm with ambience air. In this study, two coffee forms (Ripe coffee cherries; RCC and parchment coffee; PC) and three distributor hole angles (45°, 60° and 90°) are examined. The experimental result shown that the fluidization behavior is influenced by coffee form and distributor hole angle. The RCC and distributor hole angle of 60° provided the low pressure drop throughout the superficial air velocity. The low values of Vmf and SEC were also achieved in the RCC and distributor hole angle of 60°.
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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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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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Enhancing biodiesel yield and purification with a recently developed centrifuge machine: A response surface methodology approach
(2024-04-15)
Limmun, Warunee
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Chungcharoen, Thatchapol
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Rattanamechaiskul, Chaiwat
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Phetpan, Kittisak
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Limmun, Wanida
Biodiesel production processes, such as gravity settling, have limitations in terms of biodiesel yield, purification efficiency, operating time in the separation process, and more extensive equipment. Therefore, this study has focused on using a recently developed centrifuge machine for biodiesel separation to address these challenges due to its compact design, high efficiency, and simplicity. Additionally, this study aimed to optimize the separation efficiency of glycerol from biodiesel using a centrifuge machine, employing response surface methodology (RSM) with central composite design (CCD). The optimum conditions for separating glycerol from biodiesel via centrifuge machine are a rotation speed of 1800 rpm, a mixture flow rate of 192.25 ml/min, and a temperature of 55 °C, respectively. In optimum conditions, 94.52% separation efficiency was achieved. Biodiesel production can be improved, leading to higher yields and greater purity. The utilization of RSM proved valuable in determining the optimum conditions for separation. Furthermore, the machine successfully separated the biodiesel to meet ASTM D6751 and EN 14,214 standards. The results highlight the potential of the centrifuge machine for efficient and reliable biodiesel production, contributing to the advancement of the biodiesel industry.
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Limmun, Warunee

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