Assawasaengrat, Pornsawan

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Assawasaengrat, Pornsawan
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Assawasaengrat, P.
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pornsawan.as@kmitl.ac.th

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    Dimethyl ether synthesis from methanol over diatomite catalyst modified using nitric acid treatment
    (2016-08-02)
    Pranee, Watcharakorn
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    Neramittagapong, Sutasinee
    ;
    Assawasaengrat, Pornsawan
    ;
    Neramittagapong, Arthit
    Dimethyl ether synthesis from methanol over diatomite catalysts modified using nitric acid was investigated. The catalytic performance of diatomite was tested in a fixed-bed reactor under atmospheric pressure and within the temperature range of 250–350°C. It was discovered that high acidity of the catalyst yielded a higher methanol conversion rate. Moreover, it was revealed that the acidity of the catalyst surface was controlled by Al<sup>(IV)</sup> ions whereas basicity of the catalyst surface was determined by Al<sup>(V)</sup> and Al<sup>(VI)</sup> ions. From this finding, the authors were able to propose the mechanism of DME synthesis from methanol over treated diatomite.
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    Oil palm leaf-derived nanoporous carbon via hydrothermal carbonization combined with NaOH microwave activation for tetracycline adsorption
    (2025-11-01)
    Chanpee, Sirayu
    ;
    Apinyakul, Naruemon
    ;
    Kaewtrakulchai, Napat
    ;
    Khemasiri, Narathon
    ;
    Eiad-ua, Apiluck
    Generally, the increase in pharmaceutical industrial activities has led to a corresponding rise in water resource contamination. Efforts have been dedicated to addressing the urgent challenge of waste biomass disposal by developing recycling methods capable of producing bio-adsorbents. Adsorption is a promising approach for removing tetracycline contaminants, owing to its simplicity, stability, and cost-effectiveness. In this study, a low-cost activated biochar was successfully developed using oil palm leaf (OPL) via hydrothermal carbonization (HTC) combined microwave-assisted pyrolysis system (MAPS) using sodium hydroxide (NaOH). The HTC and MAPS processes enhanced high mass yield, porosity, energy efficiency, and reduced reaction time. NaOH treatment improved the porosity of the activated biochar derived from OPL, resulting primarily in a mesoporous structure. However, NaOH treatment via the MAPS process increased surface area and porosity. Among the samples tested, OPLC-NaOH-1:1 exhibited the largest surface area and highest porosity, making it the chosen candidate for further TC adsorption tests. The adsorption experiments revealed that the Langmuir isotherm model and the pseudo-second-order kinetic model accurately matched the experimental data, suggesting a mono-layered adsorption mechanism due to micropores and chemisorption interactions. Additionally, thermodynamic analysis indicated an endothermic and spontaneous reaction during the adsorption process. The adsorption of nanoporous carbon for TC was primarily regulated by pore filling, hydrogen bonding, electrostatic effects, and π-π interactions also playing a significant role. Overall, this study highlights the potential of utilizing OPL waste as a sustainable material for producing nanoporous carbon and underscores the effectiveness of nanoporous carbon for adsorbing antibiotics.
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    Lignin removal from synthetic wastewater via Fenton-like reaction over Cu supported on MCM-41 derived from bagasse: Optimization and reaction intermediates
    (2023-02-01)
    Sriprom, Pongsert
    ;
    Neramittagapong, Sutasinee
    ;
    Lin, Chitsan
    ;
    Neramittagapong, Arthit
    ;
    Assawasaengrat, Pornsawan
    Lignin degradation was performed using a Fenton-like oxidation reaction with Cu supported on MCM-41, derived from bagasse (Cu-BG-MCM-41), as the catalyst. The optimal degradation conditions required to remove a predetermined amount of lignin (95%) from an effluent were determined. Based on the literature review and preliminary tests, the critical parameters determining the operating conditions include temperature, catalyst loading, pH, H<inf>2</inf>O<inf>2</inf> concentration, and reaction time. The experimental design and working conditions were based on Box–Behnken design. The reaction products were analyzed via UV–vis and gas chromatography-mass spectrometry. Response surface methodology (RSM) was used to predict the optimum operating conditions for the Fenton-like reaction for 95% lignin degradation, which were a temperature of 80 °C, initial pH of 9, H<inf>2</inf>O<inf>2</inf> concentration of 1 mL/L, catalyst loading of 1.0 g/L, and reaction time of 30 min. These conditions were validated three times and the achieved percentage of lignin degradation was 95 ± 2%. This is close to the value of 95% used in the RSM to determine the optimum operating conditions, thus verifying the model. The catalyst was stable and functioned well under the optimum design conditions. Moreover, the reaction could be used to obtain high-value intermediate products if stopped after 5 min. Finally, lignin was degraded into vanillin, a higher-value product. As expected, the proposed Fenton-like approach expanded the pH working range from less than 4 to 5–9.
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    Optimizing Ammonia Adsorption Using Activated Carbon from Tamarind Pulp
    (2021-01-01)
    Na-Lampang, Chaiyawat
    ;
    Assawasaengrat, Pornsawan
    ;
    Phumjan, Lamphung
    ;
    Narkrugsa, Woatthichai
    ;
    Sriprom, Pongsert
    Ammonia is an essential waste from fish and shrimp which has an effect on fish and shrimp transportation for export. This study aimed to remove ammonia by Activated Carbon adsorption. The activated carbon was prepared from Tamarind pulp using different methods (NaOH, H2SO4, the hydrothermal technique and activated by H2SO4 and H2SO4 hydrothermal followed by NaOH). The Activated Carbon was characterized by and Iodine number and Fourier Transform I nfrared Spectroscopy (FT-IR). The results showed that the iodine number of activated carbon prepared by the hydrothermal technique and activated by H2SO4 have the highest surface area and porosity at 537 mg/g, and the functional group on activated carbon surface is carbonyl and sulfonyl group. For ammonia adsorption, the experiments were designed by Box-Behnken design at 3 factors 3 levels including Contact time (10, 95 and 180 min), Dosage of activated carbon (0.5, 1.25 and 2.0 g) and pH of the solution (2, 6.5 and 11). The concentration of ammonia was determined by UV-Visible spectrophotometer. The result showed that the main effects and the interaction effects were found significant effect on ammonia adsorption at confidence level of 95%. However, the interaction effects between contact time and activated carbon dosage was insignificant. Finally, the optimized results suggested that 48.32 ± 0.82% of ammonia concentration could be removed by activated carbon from tamarind pulp under the following conditions: PH of 11, a contact time of 95 min, and activated carbon dosage of 2 g/100 mL. The results are believed to be of importance to fish and shrimp transportation for reduced ammonia and other similar applications.
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    Optimization of hydrothermal carbonization of Rhizoclonium riparium macroalgae using response surface methodology for high-performance solid biofuel production
    (2026-01-01)
    Chanpee, Sirayu
    ;
    Jadsadajerm, Supachai
    ;
    Manatura, Kanit
    ;
    Wongrerkdee, Sutthipoj
    ;
    Eiad-ua, Apiluck
    Hydrothermal carbonization (HTC) was adopted as a promising approach for improving fuel quality for several high-moist biomass. In this study, the Rhizoclonium riparium macroalgae (RMA), an abundant marine alga in an aquaculture pond, was successfully converted into hydrochars as a sustainable solid biofuel. The Box Behnken design (BBD) was applied for the HTC experiment to investigate the individual and interactive effects of operating parameters, including HTC temperature, reaction time, and water ratio, on hydrochar physicochemical characteristics and fuel properties. The response surface optimization (RSM) revealed maximum mass yield (MY) of 79.1%, higher heating value (HHV) of 23.6 MJ/kg, and energy yield (EY) of 94.4%. The RSM-BBD of process parameters and their HTC effects showed that the decreasing MY and EY were significantly due to the HTC temperature and residence time. From ANOVA analysis, temperature, time, and water ratio were the most significant parameters responding to MY, HHV, and EY. The optimal conditions for hydrothermal carbonization (HTC) of RMA as a solid biofuel were determined to be a temperature of 200 °C, a duration of 2 h, and a water-to-biomass ratio of 1:1, producing the highest energy yield (EY) of 95.3%. Utilizing RSM-BBD to investigate HTC parameters for hydrochar production is a suitable effort for technical scalability.
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    Adsorption of Ammonia Nitrogen in Aqueous Solution Using Zeolite A
    (2019-10-25)
    Assawasaengrat, P.
    ;
    Rueangdechawiwat, R.
    The capacity of alternative adsorbents including rice straw, delignified rice straw and zeolite A for ammonia nitrogen removal from aqueous solution was investigated. The adsorption experiments were carried out in batch system with initial ammonia nitrogen concentration of 0.5 mg-N/l, 1000 ml ammonia nitrogen solution for 1 g of adsorbent. Experimental data indicated that rice straw and delignified rice straw cannot adsorb ammonia nitrogen. However, zeolite A provided rapidly adsorption capacity for ammonia nitrogen removal. The amount of ammonia nitrogen adsorbed by zeolite A was 0.256 mg/g at 1 minute after the experiment was initially conducted and slightly stable at 0.275 mg/g after 10 minutes. The adsorption experiments were carried out at 0.25, 0.5, 1.0, 2.0, 4.0, and 8.0 mg-N/l of ammonia nitrogen concentration. The results indicated that zeolite A had the adsorption capacity of 0.102, 0.294, 0.551, 1.153, 2.303, and 3.897 mg/g respectively at equilibrium time. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. Based on R<sup>2</sup>, Freundlich model was more promising to represent the adsorption data than Langmuir model.
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    Nanoporous Carbon from Oil Palm Leaves via Hydrothermal Carbonization-Combined KOH Activation for Paraquat Removal
    (2022-08-01)
    Chanpee, Sirayu
    ;
    Kaewtrakulchai, Napat
    ;
    Khemasiri, Narathon
    ;
    Eiad-ua, Apiluck
    ;
    Assawasaengrat, Pornsawan
    In this study, nano-porous carbon was completely obtained from oil palm leaves (OPL) by hydrothermal pretreatment with chemical activation, using potassium hydroxide (KOH) as an activating agent. Potassium hydroxide was varied, with different ratios of 1:0.25, 1:1, and 1:4 (C: KOH; w/w) during activation. The physical morphology of nano-porous carbon has a spongy, sponge-like structure indicating an increase in specific surface area and porosity with the increasing amount of KOH activating agent. The highest specific surface area of OPL nano-porous carbon is approximately 1685 m<sup>2</sup>·g<sup>−1</sup>, with a total pore volume of 0.907 cm<sup>3</sup>·g<sup>−1</sup>. Moreover, the OPL nano-porous carbon significantly showed a mesoporous structure designed specifically to remove water pollutants. The adsorptive behavior of OPL nano-porous carbon was quantified by using paraquat as the target pollutant. The equilibrium analyzes were explained by the Langmuir model isotherm and pseudo-second-order kinetics. The maximum efficiency of paraquat removal in wastewater was 79%, at a paraquat concentration of 400 mg·L<sup>−1</sup>, for 10 min in the adsorption experiment. The results of this work demonstrated the practical application of nano-porous carbon derived from oil palm leaves as an alternative adsorbent for removing paraquat and other organic matter in wastewater.
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    Soluble and Insoluble Varnish Test Methods for Trending Varnish Buildup in Mineral Turbine Oil
    (2022-12-01)
    Chokelarb, Wasan
    ;
    Assawasaengrat, Pornsawan
    ;
    Sitton, Andy
    ;
    Sirisithichote, Thanant
    ;
    Sriprom, Pongsert
    Varnish problems in turbine oil of power plants in Thailand are still an issue today. The problems are the coefficient of friction of the oil will increase along with the increase in varnish concentration and varnish deposits. This creates problems in starting/re-starting of the turbine. Even with the advent of oil manufacturing research to improve base oil quality and antioxidant additive, varnish contamination starting problems have been one of the most concerning problems for maintenance. The most recent version of ASTM D4378-20 suggests that maintenance personnel should test their in-service turbine oil and monitor the membrane patch colorimetry with a warning limit at ∆E 30. This monitoring test is known as ASTM D7843-20 Standard Test Method for Measurement of Lubricant Generated Insoluble Color Bodies in In-Service Turbine Oils using Membrane Patch Colorimetry (MPC). This study introduces the monitoring of soluble color bodies, in addition to the insoluble, at the same time. Focusing only on the value of insoluble-MPC test can sometimes be misleading and may cause inaccurate and ineffective maintenance decisions. In this paper, both soluble and insoluble color body analytical results from in-service gas turbine oils will be presented. Three power plants were monitored for both soluble and insoluble varnish. It will show how the use of a combination of soluble and insoluble color body assessments of the turbine oils would further improve the oil diagnostic services of turbine lubricants by providing insights into the capability of the lubricants to solubilize the oxidation by-products of the antioxidants and the highly refined base oil. Appropriate varnish removal technologies were also decided and applied to respond proactively to the varnish issues.
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    Optimization of lignin conversion to phenol via partial oxidation of synthesized wastewater containing lignin
    (2020-12-01)
    Sriprom, Pongsert
    ;
    Leephisuth, Pornyamon
    ;
    Assawasaengrat, Pornsawan
    ;
    Neramittagapong, Arthit
    ;
    Neramittagapong, Sutasinee
    This work was to optimize operating parameters for phenol production via partial oxidation. The essential settings, NaOH loading of 4–20 g/L, reaction temperatures of 140–180 °C, and time of 15–45 min, were set as the independent parameters for designing the experiments. A set of tests was generated using Box–Behnken Design (BBD) and performed in a high-pressure reactor at the constant air pressure of 2 bars. A produced phenol concentration was assigned as a response target for evaluating an optimal condition. From the results, a quadratic model of actual data was fit with high accuracy (R<sup>2</sup> of 94.1%). A response surface methodology (RSM) was used to evaluate the operating parameters effect on the phenol formation. It showed that the temperature rising affected phenol formation due to the creation of aldehydes at low temperatures and phenol re-polymerization. The presence of NaOH plays an essential role in the production of phenol. It may increase the hydroxyl group's rate to an aromatic ring that yields a high percentage of phenol production. For the reaction time, the longer time gave a higher yield of phenol. However, it slightly increased after 30 min. The predicted optimal condition was determined at the temperature of 161 °C, the NaOH loading of 16.4 mg/L, and the reaction time of 36.2 min. Three experiments were performed at the optimal point to verify the prediction. It was found that the phenol concentration of 30 ± 1 mg/L was yielded at this condition. Moreover, the reaction temperature and the initial pressure of air were not severe. It indicates that the partial oxidation of aqueous lignin solution can produce phenol at mild conditions.
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    Catalytic wet-air oxidation of aniline removal from synthetic wastewater
    (2014-01-01)
    Sriprom, Pongsert
    ;
    Assawasaengrat, Pornsawan
    ;
    Neramittagapong, Arthit
    ;
    Neramittagapong, Sutasinee
    Wet-air oxidation (WAO) and catalytic wet-air oxidation (CWAO) over CuO/Al<inf>2</inf>O<inf>3</inf> and NiO/Al<inf>2</inf>O<inf>3</inf> catalysts for aniline removal were investigated. The oxidation reaction was carried out in a 1000-ml high-pressure batch reactor. The temperatures of 160, 200 and 260°C and the pressures of 5 and 10 bars were generally applied for 120 min. CuO/Al<inf>2</inf>O<inf>3</inf> and NiO/Al<inf>2</inf>O<inf>3</inf> catalysts were prepared by impregnation method. It is found from the results that aniline was completely degraded at these conditions. However, aniline was converted into other organic carbons which remained in the solution. So COD was found in the solution after the reaction. It is seen from the results that 56% of COD was removed by WAO at 200°C and 10 bars for 120 min. The CWAO over CuO/Al<inf>2</inf>O<inf>3</inf> catalyst showed higher COD removal (76%) than NiO/Al<inf>2</inf>O<inf>3</inf> catalyst (60%). The types of metal oxide had an effect to the activity of COD removal; that is, CuO showed higher COD removal than NiO. The WAO and CWAO of COD removal in aniline solution were the first-order kinetic with the constant reaction rate and activation energy for CuO/Al<inf>2</inf>O<inf>3</inf> of 0.234 s<sup>-1</sup> and 11.772 kJ/mol, respectively. © (2014) Trans Tech Publications, Switzerland.