KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 8 of 8

Some of the metrics are blocked by your
consent settings
Low-Cost Activated Carbon for Methylene Blue Adsorption Using Inert Gas-Free Carbonization and Microwave Activation
(2025-01-01)
Kongtragoul, Pornprapa
;
Keeratirawee, Kanchalar
;
Choola-Aied, Orasa
-This study investigated the preparation of activated carbon from spent coffee grounds for methylene blue adsorption using inert gas-free carbonization and microwave activation. Spent coffee grounds were obtained from a local coffee shop in Pathio, Chumphon, Thailand. The coffee grounds were pretreated with 1M H<inf>2</inf>SO<inf>4</inf> before undergoing carbonization at 600 ºC for 3 h in a limited-oxygen atmosphere. The obtained carbon materials were chemically activated with zinc chloride (ZnCl<inf>2</inf>) and physically activated using a microwave-assisted method at 300 W for 180 seconds. The adsorption of methylene blue was evaluated using a batch method. Methylene blue adsorption contact time, effect of pH, and initial concentration were investigated. The maximum adsorption capacity of the activated carbon for methylene blue removal was found to be 29.24 mg/g. The prepared activated carbon exhibited a BET surface area of 70.08 m2/g and reached equilibrium in 120 min at the optimum pH of 9. The adsorption isotherm was consistent with the Freundlich model, while the adsorption kinetics followed a pseudo-second-order model. The findings indicate that activated carbon is a cost-effective and efficient adsorbent for methylene blue removal from aqueous solutions.
Some of the metrics are blocked by your
consent settings
Preparation of Low-Cost Activated Carbon from Spent Coffee Grounds for Rhodamine B Removal
(2025-01-01)
Keeratirawee, Kanchalar
;
Choola-aied, Orasa
;
Kongtragoul, Pornprapa
A low-cost coffee-based activated carbon for Rhodamine B (RhB) removal was investigated. Spent coffee grounds obtained from a local coffee shop in Pathio, Chumphon, Thailand, were utilized as the raw material to produce biochar. The coffee grounds were pre-treated by washing with 1M H2SO4 before carbonization at 600 ºC for 2 h under a limit-oxygen atmosphere. The acid washing process was found to be a promising method for preparing activated carbon without requiring an inert gas flow during the carbonization. This approach resulted in activated carbon free of ash after carbonization. The carbonized coffee grounds were activated using a microwave-assisted process with KOH as the activating agent. The performance of the prepared activated carbon for Rhodamine B adsorption was evaluated using the batch method. Key parameters, including initial concentration of Rhodamine B (3-11 mg/L), pH (3-11), and contact time (15-150 min), were optimized. The maximum adsorption capacity was 16 mg/g of adsorbents. The optimal pH for Rhodamine B adsorption was found to be 7. The adsorption of Rhodamine B onto the adsorbent fits a Langmuir isotherm and a pseudo-second-order kinetic model. The study revealed that the prepared activated carbon from waste coffee grounds is an efficient and affordable solution for removing Rhodamine B contaminants from the water system.
Some of the metrics are blocked by your
consent settings
Rapid colorimetric assay based on the oxidation of 2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid-diammonium salt for nitrite detection in meat products
(2024-01-01)
Jantra, Jongjit
;
Arsawiset, Supattra
;
Teepoo, Siriwan
;
Keeratirawee, Kanchalar
This work developed a rapid colorimetric method for nitrite detection in meat products. The detection was based on the reaction of nitrite with 60 mM HCl to produce radicals which further oxidized ABTS (50 µM) to form a water-soluble blue-green product (ABTS•+). The absorbance was measured at a maximum absorption wavelength of 412.5 nm. Parameters such as concentration of HCl, concentration of ABTS and reaction time were evaluated. The absorbance was linearly proportional to the concentration of nitrite (0.1–20 µM) with the limit of detection of 0.34 µM. The proposed method was a time-saving assay since it required only 2 min to complete one measurement. There was no effect of the interference produced by other ions. The assay was robust with 2.5%RSD (n = 50). In meat product samples, high accuracy was observed with the recoveries between 100 ± 2.2% and 105 ± 3.7%. The amount of nitrite in meat products detected by the ABTS method was found in the range of 5.41 − 7.62 mg/kg. The conventional Griess method was applied to determine nitrite in the same meat products. There was no statistically significant difference between the two methods (P = 0.05).
Some of the metrics are blocked by your
consent settings
EFFECT OF ZINC OXIDE NANOPARTICLES AGAINST PHYTOPHTHORA SPP. CAUSING DURIAN DISEASES IN VITRO
(2024-01-01)
Keeratirawee, Kanchalar
;
Kongtragoul, Pornprapa
;
Pantakan, Sansanee
The efficiency of zinc oxide nanoparticles (ZnO-NPs) in inhibiting Phytophthora spp. growth in both durian fruits and stems is demonstrated. The size of ZnO-NPs used was in range of 25-50 nm in diameter. Diseased durian sample were collected from a durian orchard located in southern of Thailand. The pathogen of diseased durian was isolated for subsequent morphological identification. Three distinct strains of Phytophthora spp. (designated as PHY41, PHY45, PHY49) were successfully isolated and were found in colonies with rings and stellate pattern, ovoid, limoniform sporangium with semi-papillate or papillate, and formation chlamydospores. All isolates were exhibiting 100% pathogenicity on durian, as indicated by the disease incidence (DI). The concentration of ZnO-NPs played a crucial role in suppressing the growth of Phytophthora spp. in all isolates. Higher concentration of ZnO-NPs resulted in increased inhibition of growth. ZnO-NPs at the concentration of 2000 µg/mL effectively suppressed the mycelial growth of all fungi isolates at 57.76-69.84%. Additionally, ZnO-NPs at the concentration of 500 µg/mL completely inhibited the sporulation only in the PHY49 strains. Furthermore, ZnO-NPs concentration ranging from 1000-2000 µg/mL resulted in completed inhibition in sporulation in all Phytophthora spp. isolates. The result demonstrated that ZnO-NPs at all concentrations effectively delayed the germination of Phytophthora spp.
Some of the metrics are blocked by your
consent settings
Low-cost electronic circuitry for photoacoustic gas sensing
(2022-04-01)
Keeratirawee, Kanchalar
;
Furter, Jasmine S.
;
Hauser, Peter C.
The circuitry comprises a sine wave generator based on direct digital synthesis, a laser diode driver module, a band-pass frequency filter, a synchronous detector with phase adjustment circuitry and a low pass filter to form an analog lock-in amplifier, and an analog-to-digital converter. A 32-bit ARM microcontroller programmed with the open source Mecrisp dialect of the Forth interpreter language is used to set the frequency, and read the data from the analog-to-digital converter. The circuitry is tethered via a serial interface to a personal computer. A graphical user interface written in Phython allows easy interaction with the microcontroller by sending the appropriate Forth commands. The data acquired is visualized and stored on the personal computer for further processing. The circuitry is easy to build as it is based on through-hole devices, except for two necessary surface mount items, which, however, still can be soldered with a fine tipped soldering iron. The performance of the circuitry was demonstrated by the photoacoustic detection of NO<inf>2</inf> using a laser diode with a wavelength of 450 nm.
Some of the metrics are blocked by your
consent settings
Determination of Binary Gas Mixtures by Measuring the Resonance Frequency in a Piezoelectric Tube
(2022-02-01)
Keeratirawee, Kanchalar
;
Hauser, Peter C.
The composition of gas mixtures may be determined via changes of the speed of sound. As this affects the resonance frequency of the gas inside a tube, indirect measurements through a frequency analysis are also possible. It is demonstrated that this may be carried out with unprecedented simplicity by the novel employment of a piezoelectric tube which serves at the same time as a resonance tube and as transducer into the electronic domain. Experiments were run using a simple diecast aluminum box as the measuring cell, inside which the piezoelectric tube made from lead zirconium titanate with 30-mm length and 5.35-mm inner diameter was suspended. A small loudspeaker placed into the cell served for excitation of the resonance. Peak frequencies between 3910 and 14,590 Hz (for pure CO<inf>2</inf> and He, respectively) were obtained. Two component mixtures of O<inf>2</inf>/N<inf>2</inf>, CO<inf>2</inf>/N<inf>2</inf>, and He/N<inf>2</inf> at various composition were tested. A linear frequency change from 4790 to 5100 Hz was observed when going from pure O<inf>2</inf> to pure N<inf>2</inf> .
Some of the metrics are blocked by your
consent settings
Piezoelectric tube as resonant transducer for gas-phase photoacoustics
(2021-02-22)
Keeratirawee, Kanchalar
;
Hauser, Peter C.
The use of a piezoelectric tube for the photoacoustic gas-phase determination of NO<inf>2</inf> as a model analyte is demonstrated. The tube is made from lead zirconate titanate with 30 mm length and 5.35 mm internal diameter. Its inner and outer surfaces are coated with electrodes. The tube serves as both, resonance body and transducer. The design is thus simpler than the usual combination of resonance tube and microphone as the two functions are embodied in the same component. The main resonance frequency of the tube was found to be 5341 Hz. A blue laser diode emitting at 450 nm was employed as light source for the determination of NO<inf>2</inf>. The limit of detection was determined as 83 ppbV and the calibration curve was linear with a coefficient of determination (r2) of 0.9998 up to the highest concentration of 15 ppmV tested.
Some of the metrics are blocked by your
consent settings
Photoacoustic detection of ozone with a red laser diode
(2021-02-01)
Keeratirawee, Kanchalar
;
Hauser, Peter C.
The photoacoustic detection of ozone using the Chappuis band is demonstrated. A visible red laser diode emitting at 638 nm was employed as a light source. The photoacoustic cell consisted of a conventional resonance tube with a MEMS (microelectromechanical systems) microphone placed outside an opening along the tube. A calibration curve for the range from 33 ppmV to 215 ppmV was found to be highly linear with a coefficient of determination (r2) of 0.9999, when allowing for different measurement frequencies to account for shifts in the speed of sound due to changes in the gas matrix. The limit of detection was found to be 1.6 ppmV for an optical power of the laser diode of about 130 mW.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results