Wongpromrat, Patthranit

Preferred name

Main Affiliation

School of Engineering

patthranit.wo@kmitl.ac.th

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Classification of saline water for irrigated agriculture using near infrared spectroscopy coupled with pattern recognition techniques
(2019-09-24)
Lapcharoensuk, Ravipat
;
Phuphanutada, Jirawat
;
Wongpromrat, Patthranit
This research aimed to create near infrared (NIR) spectroscopy models for the classification of saline water with a pattern recognition technique. A total of 112 water samples were collected from the Tha Chin river basin in Thailand. Water samples with salinity less than 0.2 g/l were identified as suitable for agriculture, while water samples with salinity higher than 0.2 g/l were found to be unsuitable. The NIR spectra of water samples were recorded using a Fourier transform (FT) NIR spectrometer in the wavenumber of 12,500-4,000 cm-1. The salinity of each water sample was analysed by electrical conductivity meter. Identification models were established with 5 supervised pattern recognition techniques including k-nearest neighbour (k-NN), support vector machine (SVM), artificial neural network (ANN), soft independent modelling of class analogies (SIMCA), and partial least squares-discriminant analysis (PLS-DA). The performance of the NIR model was carried out with a split-test method. About 80% of spectra (90 spectra) were randomly selected to develop the classification models. After model development, the NIR spectroscopy models were used to classify the categories of the remaining samples (22 samples). The ANN model showed the highest performance for classifying saline water with precision, recall, F-measure and accuracy of 84.6%, 100.0%, 91.7% and 90.9%, respectively. Other techniques presented satisfactory classification results with accuracy greater than 68.2%. This point indicated that NIR spectroscopy coupled with the pattern recognition technique could be applied to classify saline water for agricultural use according to salinity level in natural resources.
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A study of atrazine adsorption by using the rice straw synthesized adsorbent
(2018-08-14)
Samanmulya, Thachanan
;
Deetae, Pawinee
;
Wongpromrat, Patthranit
This study focused on adsorption of atrazine in adsorbent synthesized from Rice Straw. Rice Straw biochar were used in the study as they exhibited significantly high adsorption capacity for pesticide. Briefly, rice straw was pyrolysis at 600°C under nitrogen then biochar was modified using H<inf>3</inf>PO<inf>4</inf>. Biochar were characterized for their physico-chemical characteristics. The elemental analysis of biochar was performed using CHNS Analysis. The surface area and pore volume of adsorbents were estimated using the Brunauer, Emmett, and Teller (BET Analysis). In parts of Batch adsorption experiments was performed in range of room temperature and were divided to 2 parts. Part 1: Study of the kinetics adsorption was investigated using two models, namely, the pseudo-first-order and the pseudo-second-order models. Part 2: study of Adsorption isotherms. The results of CHNS analysis shows the elemental analysis that 51.795% of C, 0.763% of H, 1.634% of N and 0.654 % of S and the result of BET Analysis shows the surface area is 372.4 m2/g and pore volume of adsorbents is 0.315 cm3. From plotting between qt(mg/g) and time (t) shows the dynamics of the adsorption of atrazine onto the biochar at 15 ppm of initial atrazine concentrations. In general, atrazine was adsorbed quickly around 1-30 min. This could be due to fast mass transfer of solute from the solution to surface of adsorbent s as a result of concentration gradient of the solute. The study of the kinetics adsorption showed that the pseudo-second-order model best described the adsorption which agrees with chemisorption as the rate controlling mechanism.
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Xps analysis of oxide formed on the surface of co-28cr-6mo-1si alloy oxidized at 550 ºc
(2020-01-01)
Tunthawiroon, Phacharaphon
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Kitiwan, Mettaya
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Wongpromrat, Patthranit
;
Chiba, Akihiko
This work investigated the influence of oxidation durations on the formation of oxide on the surface of wrought Co-28Cr-6Mo-1Si alloy. The iso-thermal oxidation was individually performed in air at 550ºC for 4, 12 and 24 h. For comparison, the surface of the non-oxidized Co-28Cr-6Mo-1Si alloy was concurrently examined. The chemical compositions of the non-oxidized and oxidized alloys were principally analyzed via X-ray photoelectron spectroscopy (XPS). The XPS results revealed that the surface of the non-oxidized alloy enriched in Cr-oxide. After oxidation treatment, the Co-oxide, existing as Co2+ state was observed coexisting with two Cr-oxide states, Cr3+ and Cr4+. The low concentrations of Mo6+ were also observed on the oxidized alloy surface. With the increase in oxidation durations, the Co-oxide was suppressed by Cr-oxide. The XPS depth profile analysis indicated that the thickness of the oxide film increased with increasing the oxidation duration.
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Study of atrazine removal by an adsorbent synthesised by water hyacinth
(2018-08-14)
Nuntamongkol, Sitanan
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Deetae, Pawinee
;
Wongpromrat, Patthranit
In this work, water hyacinth was selected as a raw materials for synthesising the activated carbon used for removing atrazine, one of the most famous herbicides used in Thailand, from water. Three different treating methods were performed in order to attain the best adsorbent; untreated (AC), HCl-treated (HCl-AC) and NaOH-treated (NaOH-AC) activated carbons. After pyrolysis, NaOH-AC became ash, so it was not suitable for using as an adsorbent. Among these, HCl-AC was the best adsorbent for removing atrazine from water because of its highest surface areas. The adsorption experiments using AC and HCl-AC as the adsorbents confirmed that the adsorption efficiency of HCl-AC was higher than that of AC. In addition, the adsorption isotherm of HCl-AC was investigated by varying the atrazine initial concentration in the range of 3-15 ppm. The results best fitted with Langmuir isotherm that means this adsorption phenomenon was chemisorption with the maximum adsorbent capacity of 24.510 mg/g, Langmuir isotherm constant of 10.462 L/mg and the separation factor of 0.006 indicating that the equilibrium sorption of atrazine by HCl-AC was favourable.
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Development of the near infrared spectroscopy model for detecting herbicide concentrations contaminated in water
(2019-09-09)
Lapcharoensuk, Ravipat
;
Wongpromrat, Patthranit
This research aims to develop the near infrared spectroscopy (NIR) models for detecting herbicide concentrations contaminated in water. Atrazine, the organochlorine herbicide, solution in the concentration range of 0-15 ppm were prepared in distilled water. Near infrared spectra were scanned by using Fourier transform spectrometer at wavenumbers of 12,500-4,000 cm-1 (800-2, 500 nm). Partial least square regression technique was used to establish the NIR models for detecting herbicide concentrations. The developed models showed high prediction potential of herbicide concentrations contaminated in water with the R2 of 0.97, RMSEE of 0.899 ppm, bias of -0.0003 ppm and RPD of 5.43. This indicated that these models can apply to analyse contamination of atrazine in the natural water sources.
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Study of atrazine adsorption kinetics by using an activated carbon synthesised from water hyacinth
(2019-09-24)
Deetae, Pawinee
;
Wongpromrat, Patthranit
In this work, atrazine, one of the most widely used herbicides in Thailand, was removed from water by activated carbon synthesized from water hyacinth. Before adsorption, 3 types of activated carbons used as adsorbents were prepared by different chemical treatment methods; untreated activated carbon (AC), HCl-treated activated carbon (HCl-AC) and NaOH-treated activated carbon (NaOH-AC). After pyrolysis, NaOH-AC became ash, so it was not suitable for using as an adsorbent. Brunauer-Emmett-Teller (BET) and CHNS methods were used to characterised 2 other adsorbents and the results showed that HCl treatment could improve the surface area and carbon content. This led to the better performance of HCl-AC for removing atrazine from water comparing to AC confirming by the adsorption experiments. In addition, the adsorption kinetics of HCl-AC, the best adsorbent in this research, was investigated by fitting with 4 kinetics models. The results showed that pseudo-second-order was the best kinetics model describing that the atrazine adsorption of HCl-AC was limited by adsorption and 2 active sites of adsorbent were required for adsorbing 1 molecule of atrazine.

Wongpromrat, Patthranit

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