Biomedical subjects

Chao-Yin Kuo

Publications and source records attributed to Chao-Yin Kuo.

7 recordsLinked to original sources

PubMed2006

Estimating air quality in a traffic tunnel using a forecasting combination model.

This study compared three forecasting methods based on their accuracy or absolute errors in forecasting air pollution in a traffic tunnel: the Grey model (GM), the Crank-Nicholson implicit scheme model, and the forecasting combination model (FCM). Three criteria, root mean square error (RMSE), the mean absolute error (MAE) and mean absolute percentage error (MAPE), were applied to the models and the FCM model displayed all of the characteristics of a good forecasting model. The correlation coefficient (r) for the FCM model equaled 0.94 (Upwind), 0.98 (Middle) and 0.98 (Downwind). This study indicated that FCM can be used to accurately forecast CO pollution in the Kaohsiung Cross Harbor Tunnel.

Air Pollutants↗

PubMed2005

Removal of copper from industrial sludge by traditional and microwave acid extraction.

This work elucidates the removal of copper from industrial sludge by traditional and microwave acid extraction. The effects of acid concentration, extraction time, sludge particle size and solid/liquid (S/L) ratio on copper removal efficiency were evaluated. Leaching with more concentrated acid yielded greater copper content from the industrial sludge. The experimental findings reveal that the most economical traditional extraction conditions were the use of 1N sulfuric or nitric acid for 60 min at an S/L ratio of 1/20; however, at an S/L ratio of 1/6, the extraction time needed to achieve the same copper removal efficiency was increased to 36 h. Increasing the microwave power and reducing the S/L ratio increased the copper extraction efficiency and the effect in the larger S/L ratio system was more significant. A comparison of the results of microwave-assisted (microwave only) and microwave-enhanced (microwave with addition of active carbon) acid extraction demonstrated that under both conditions, S/L ratio=1/6 and 1/20; adding active carbon shortened the extraction time required to achieve 80% copper extraction efficiency from 20 to 10 min. These experimental results indicate that the most important factors that most strongly affected microwave acid extraction were the addition of a microwave absorber, the microwave power input and the S/L ratio. The sludge particle size did not significantly affect the copper extraction. The results reveal that sulfuric acid was an effective extractant and that the copper fraction in the extracted sludge shifted from being mostly bound to the Fe-Mn oxides and organic matter, to being mostly bound to organic matter and remaining as a residue during acid extraction.

Acids↗

PubMed2005

Leaching efficiency of copper from industrial sludge with traditional acid extraction (TAE) and microwave assisted treatment (MAT).

In this study various leaching technologies were applied to extract heavy metals from sludge from the printed circuit board process. These methods included traditional acid extraction (TAE) and microwave assisted treatment (MAT). The target heavy metal was copper. Experiments were performed to determine the acid the leaching efficiency by changing operating conditions, including acid type and concentration, leaching time, microwave power, and solid to liquid ratio (S/L). The TAE method demonstrated that copper leaching from a sludge of fine particle sizes (d < 150 microm) was 74% efficient at an S/L of 1/6, a leaching time of 18 hr, using nitric acid in the leaching solution. Then, when the microwave powers were 800 W and 400 W; the leaching time was 30 mins, and the coarse particle size (d < 9.5 mm) was by 1 N sulfuric acid, the copper leaching effects were 93% and 77%, respectively. The MAT procedure reduced the leaching time and improved the leaching efficiency above that obtained by TAE.

Copper↗

PubMed2004

Adsorption effect of aqueous bichlorobiphenyls onto UV-illuminated titanium dioxide.

Bichlorobiphenyls were adsorbed onto TiO(2) (Degussa P25) in batch equilibrium experiments. The results demonstrated that a triple-layer model (TLM) surface complex formation model described the adsorption of chlorobiphenyls onto the surface of the TiO(2) solid. The surface complex configuration and the adsorption reaction may have followed the equation derived from the TLM, involving the loss of a proton during the adsorption process. This dependence indicates that the oxidation reaction between surface-adsorbed substrates and photogenerated oxidants dominates. Both sorbed and dissolved components contribute to the observed degradation rate, that is, the 4,4'-CBP degradation rates might be stated as linear functions of the sorbed and dissolved concentrations. The contribution of the concentration of solution phase in degradation pathways is not negligible.

Adsorption↗

PubMed2004

Effect of coupled semiconductor system treating aqueous 4-nitrophenol.

This article describes a method for treating aqueous 4-nitrophenol by mixing with TiO2-SnO2 coupled particles. The reactivity of single photocatalysis (TiO2 and SnO2 all as 1.2 g/L) is compared with that of mixing TiO2-SnO2 (0.6 g/L + 0.6 g/L) coupled particles. Aqueous 4-nitrophenol was treated by single photocatalysis or coupled semiconducting particles in a double-layer glass batch reactor using a 15W UV fluorescent tube at 25 degrees C and 300 rpm for mixing. The results demonstrated that pH and the concentration of TiO2 were the factors that most influenced the degradation characteristics, and that the system of TiO2-SnO2 coupled particles improved the efficiency of removal of refractory organic pollutants by 15%, by the inter-particle electron transfer (IPET) effect. The results showed that the degradation of aqueous 4-nitrophenol was 75% when coupled particles were used--better than the 60% obtained using single photocatalysis--with a reaction time of 120min.

Catalysis↗

PubMed2004

Removal of metals from industrial sludge by extraction with different acids.

This study addresses the feasibility of removing Cu and Ni from sludges of printed circuit board (PCB) plants by acidic extraction. Citric acid, acetic acid, hydrochloric acid, nitric acid, and sulfuric acid at various concentrations were experimentally examined to determine preferred conditions for removing Cu and Ni. Experimental results indicate that the removal ratios of Cu were 57% (citric acid), 79% (acetic acid), 81% (hydrochloric acid), 91% (nitric acid), and 92% (sulfuric acid), and that of Ni was 74% (citric acid), 70% (acetic acid), 75% (hydrochloric acid), 92% (nitric acid), and 93% (sulfuric acid), using 1 N extractants. The removal ratios obtained using sulfuric acid or nitric acid at a particular concentration were in the order Pb> Ni> Cu> Zn. The kinetic extraction results revealed that the extraction of Cu and Ni by nitric acid and sulfuric acid exhibited a lagphase after 60min and the removal ratio was then around 90%. The kinetic results also revealed that the extraction rate constants of Cu and Ni increased with the concentration of the acid. The extraction rate constants of Cu and Ni followed the order sulfuric acid > nitric acid > acetic acid, and it also showed that Ni was more easily extracted than Cu from PCB sludge. The total percentages of Cu extracted by 1 N acetic acid, nitric acid, and sulfuric acid, determined in three replicate extractions were 78, 94, and 94%, and those of Ni were 89, 94, and 98%, respectively. The residue sludge, following three replicate extractions using 1 N acetic acid, nitric acid, and sulfuric acid, was further tested by toxicity characteristic leaching procedures (TCLP), and more than 15 mg/L of Cu was leached, exceeding the legal concentration in Taiwan. This observation reveals that the residue sludge following three replicate extractions by acids remained hazardous waste. Further treatment, such as solidification, must be performed before the sludge is disposed of.

Acids↗

PubMed2002

Modeling competitive adsorption of molybdate, sulfate, selenate, and selenite using a Freundlich-type multi-component isotherm.

This study examined the interactions of MoO4(2-) + SO4(2-), MoO4(2-) + SeO4(2-), and MoO4(2-) + SeO3(2-) systems on gamma-Al2O3 to better understand the competitive adsorption of these anions in the natural environment. The Freundlich isotherms of anionic adsorption onto gamma-Al2O3 in single and binary solutes were also investigated to estimate the competition between these anions. Experimental results indicate that a higher concentration of competitive solute yields a higher efficiency of the competitive solute's prevention of MoO4(2-) adsorption. The most significant result was found in the MoO4(2-) + SeO3(2-) system. The Freundlich isotherm constant (n) increases with the competitive solute concentration. The suitability of a Freundlich-type isotherm, the Sheindorf-Rebuhn-Sheintuch (SRS) equation, and the modified SRS equation in representing the competitive adsorption of MoO4(2-), SO4(2-), SeO4(2-), and SeO3(2-) on gamma-Al2O3 surface, was also examined. Each set of isotherm data was found to conform to linear SRS expressions, allowing competition coefficients to be derived on a concentration basis for each binary-solute system. The competition coefficient aij and relative affinity coefficients alphaij can be seen as a way to quantify competitive interactions. The proposed SRS and modified SRS equations are simple mathematical expressions accounting for competitive interactions of anions present in a mixture for the range of concentrations over which each individual component exhibits Freundlich behavior.

Adsorption↗