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Effect of wood vinegar substitutes on acetic acid for coagulating natural para rubber sheets during the drying process
(2021-09-01)
Kalasee, Wachara
;
Dangwilailux, Panya
The coagulating properties of wood vinegar from para rubber wood, bamboo, and coconut shell used as a substitute for acetic acid in the production process of natural rubber (NR) sheets were investigated and considered. For the dirt and volatile content, the tensile strength at break, the percentage of elongation at break, and the 300% modulus, the results showed that the types of wood vinegar coagulants were not significantly different from acetic acid. However, the Mooney viscosity and plasticity retention index (PRI) properties were significantly different from those of acetic acid. The NR sheet temperature increased rapidly during the first hour after the drying process started due to heat transfer from the hot air. Afterward, the temperature of the NR sheet samples began to stabilize. When the drying process started, the drying temperature was increased, so the trend was reducing the drying time. For the yellowness index (YI) value, the increase in the YI value was related to the type of coagulating material, the increase in the airspeed, and the drying temperature. The dried sheet samples using para rubber wood vinegar as the coagulating material had a color value at the same level as acetic acid and the referent. However, the bamboo and coconut shell wood vinegars were at a lower level. In comparing the YI value data between the experimental results and prediction values, the second-degree model had a better fit in prediction than the zero-degree and first-degree models. This result was confirmed by the higher mean of the coefficient of determination. The dried sheet product coagulated by using wood vinegar had fungus growth prior to supplying it to the customer.
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Smoke particle, polycyclic aromatic hydrocarbons and total benzo[a]pyrene toxic equivalence emitted by palm oil sewage sludge bio‐char combustion
(2021-09-01)
Kalasee, Wachara
;
Dangwilailux, Panya
The size distribution, total particle mass concentration (TPMC), polycyclic aromatic hydrocarbons (PAHs) value, and total Benzo[a]pyrene Toxic Equivalence (BaPTE) concentration of smoke particles from palm oil sewage sludge (POSS) bio‐char combustion were studied. In this experiment, temperature data of the POSS bio‐char combustion were recorded in two parts: particle temperature (Tp) by using a two‐color pyrometer and temperature at 300, 500 and 800 mm, respectively, above the fire base by using K‐type thermocouples. The POSS bio‐char moisture content, clean air speed values, and burning period affected the change of temperature above the fire base. The mass median aerodynamic diameter (MMAD) values of the POSS bio‐char combustion were found to be 0.44 to 1.05 micron at various moisture contents and burning periods. The MMAD, TPMC, and PAHs values increased with increasing moisture content and decreased the POSS biochar combustion period. For the total BaPTE values, the results showed that the decrease in moisture content of the POSS bio‐char samples had a prime influence in decreasing the total BaPTE values. Meanwhile, with decreases in the clean air speed values, the total BaPTE values were increased. Comparing the total BaPTE data between the experimental results and predicted values, the first‐degree model had a better fit in predicting than the zero‐degree model; this result was confirmed by the higher mean of the coefficient of determination.
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Prediction of size distribution and mass concentration of smoke particles on moisture content and combustion period from para rubber wood burning
(2021-06-02)
Kalasee, Wachara
;
Dangwilailux, Panya
The size distribution and total particle mass concentration (TPMC) of smoke particles from para rubber wood (Hevea brasiliensis) combustion in the ribbed smoked sheet (RSS) process were studied. In this experiment, temperature data values of para rubber wood combustion were recorded at 500 mm above the base of the fire by K-type thermocouples. The wood moisture content and wood combustion period were used to find and improve an equation of smoke particle size distribution (SPSD) and TPMC by the response surface method (RSM). An eight-stage Andersen air sampler and a high-volume sampler were used to measure and calculate SPSD and TPMC, respectively. Resulting data in this experiment showed that TPMC ranged from 3.12 to 77.42 mg/m3 . SPSD was single mode in which MMAD, mass median aerodynamic diameter, ranged from 0.64 to 1.27 microns for para wood with moisture content ranging from 31.5 to 89.7% dry weight basis. The combustion period and moisture content of para wood have a direct effect on the change of temperature data above the base of the fire and the TPMC and MMAD values. For predicting TPMC and MMAD values by the para wood moisture contents in each combustion period, the results found that the second-degree model was a better plot than the first-degree model, confirmed by higher values of the coefficient of determination (R2 ).
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Size distribution, characterization and risk assessment of particle-bound polycyclic aromatic hydrocarbons during haze periods in Phayao Province, northern Thailand
(2017-11-01)
Pooltawee, Jaturaporn
;
Pimpunchat, Busayamas
;
Junyapoon, Suwannee
This study aims to investigate the concentrations and distributions of particulate matters and particle-bound polycyclic aromatic hydrocarbons (p-PAHs) in different inhalable fractions during haze periods in Phayao Province, northern Thailand and identify their possible emission sources through the characteristic ratios of selected PAHs, then determine an estimate of the potential lung cancer risk. The particulate samples were collected during haze periods between February 18 and April 8, 2014 and non-haze period from June 17 to 22, 2014 using an eight-stage cascade impactor. Each filter sample was weighed, ultrasonically extracted with acetonitrile, and then analyzed by SIM-GC-MS to identify 16 PAHs. The experimental results show that the concentrations of ultrafine (d<inf>ae</inf> < 0.4 μm), fine (0.4 μm < d<inf>ae</inf> < 2.1 μm), and coarse (d<inf>ae</inf> > 2.1 μm) particles during haze periods were in the range of 14.98–26.52 μg m−3, 62.57–101.52 μg m−3, and 55.27–89.68 μg m−3, respectively; whereas, their concentrations of 16 PAHs were in the range of 7.82–36.06 ng m−3, 26.66–61.89 ng m−3, and 9.35–30.93 ng m−3, respectively. The p-PAH distribution profiles during the haze periods were bimodal in coarse and accumulation modes, which are closely related to their particle size distributions. The characteristic ratios of BaP/BgP and INP/(BgP+InP) adsorbed on ultrafine and fine particles were 0.81–0.88 and 0.38–0.86 and 0.54–0.57 and 0.44–0.52, respectively. The values of B[a]P<inf>eq</inf> observed during haze periods varied from 9.57 to 29.05 ng m−3. Estimated lifetime cancer risks during haze periods ranged from 8.324 to 25.27 additional cases per 10,000 people exposed, which is about 10 times higher than that during non-haze period.
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Size distribution of atmospheric particulates and particulate-bound polycyclic aromatic hydrocarbons and characteristics of PAHs during haze period in Lampang Province, Northern Thailand
(2013-06-01)
Phoothiwut, Sawan
;
Junyapoon, Suwannee
Size distributions of atmospheric particulates and particulate-bound polycyclic aromatic hydrocarbons (p-PAHs) in different inhalable fractions (9.0-5.8, 5.8-4.7, 4.7-3.3, 3.3-2.1, 2.1-1.1, 1.1-0.7, 0.7-0.4, and <0.4 μm) were investigated during a haze period in Lampang Province, Northern Thailand. The particulate samples were collected using an eight-stage cascade impactor. The sample filter in each stage was weighed to determine concentration followed by ultrasonic extraction with acetonitrile and then analysis using selected ion monitoring-gas chromatograph-mass spectrophotometer to identify 16 PAHs. Similarly, smoke emission from burning rice straw in the rice field and air sample during non-burning period were also analyzed. In this study, the particle size fractions were classified into three different size ranges according to their mechanism of formation: ultrafine particles (nuclei mode, d <inf>ae</inf> < 0.4 μm), fine particles (accumulation mode, 0.4 μm < d <inf>ae</inf> < 2.1 μm) and coarse particles (d <inf>ae</inf> > 2.1 μm). Experimental results show that the average concentration of particulate matter less than 10 μm during the haze period was 3.5 times higher than that during the non-burning period. The atmospheric aerosols during the haze period contained the largest fraction of particles in nuclei mode while the emission during rice straw burning introduced the largest fraction of particles in accumulation mode. The size distributions of total PAHs during the haze period and rice straw burning were shifted towards the smaller particles relative to their particle size distribution. The size distributions of total PAHs were bimodal during the haze period and unimodal during rice straw burning. The fractions of five- and six-ring PAHs bound on the particles were predominantly detected during the haze period whilst those of three- and four-ring PAH compounds were mainly found in smoke emitted from rice straw burning. The ratio of carcinogenic and noncarcinogenic PAH compounds during the haze period was composed of more carcinogenic PAHs than that during rice straw burning. © 2013 Springer Science+Business Media Dordrecht.

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