Yuan-Chung Lin

PM, carbon, and PAH emissions from a diesel generator fuelled with soy-biodiesel blends

Biodiesels have received increasing attention as alternative fuels for diesel engines and generators. This study investigates the emissions of particulate matter (PM), total carbon (TC), e.g., organic/elemental carbons, and polycyclic aromatic hydrocarbons (PAHs) from a diesel generator fuelled with soy-biodiesel blends. Among the tested diesel blends (B0, B10 (10 vol% soy-biodiesel), B20, and B50), B20 exhibited the lowest PM emission concentration despite the loads (except the 5 kW case), whereas B10 displayed lower PM emission factors when operating at 0 and 10 kW than the other fuel blends. The emission concentrations or factors of EC, OC, and TC were the lowest when B10 or B20 was used regardless of the loading. Under all tested loads, the average concentrations of total-PAHs emitted from the generator using the B10 and B20 were lower (by 38% and 28%, respectively) than those using pure petroleum diesel fuel (B0), while the emission factors of total-PAHs decreased with an increasing ratio of biodiesel to premium diesel. With an increasing loading, although the brake specific fuel consumption decreased, the energy efficiency increased despite the bio/petroleum diesel ratio. Therefore, soy-biodiesel is promising for use as an alternative fuel for diesel generators to increase energy efficiency and reduce the PM, carbon, and PAH emissions.

Synthesis and Characterization of Organic Dyes Containing Various Donors and Acceptors

New organic dyes comprising carbazole, iminodibenzyl, or phenothiazine moieties, respectively, as the electron donors, and cyanoacetic acid or acrylic acid moieties as the electron acceptors/anchoring groups were synthesized and characterized. The influence of heteroatoms on carbazole, iminodibenzyl and phenothiazine donors, and cyano-substitution on the acid acceptor is evidenced by spectral, electrochemical, photovoltaic experiments, and density functional theory calculations. The phenothiazine dyes show solar-energy-to-electricity conversion efficiency (η) of 3.46–5.53%, whereas carbazole and iminodibenzyl dyes show η of 2.43% and 3.49%, respectively.

Multivariate analysis of heavy metal contaminations in seawater and sediments from a heavily industrialized harbor in Southern Taiwan

Heavy metal pollution, including chromium, zinc, arsenic, cadmium, mercury, copper, lead, and aluminum, in the largest industrial harbor in southern Taiwan was investigated. Increasing metal contamination was observed by monitoring heavy metal concentrations in seawater and sediments and estimating the enrichment factors, particularly those inside the harbor. Compared to other metal-polluted harbors worldwide, the presence of chromium in the sediments was relatively high. Excluding the background contribution, the harbor area was polluted by outflows from river mouths, wastewater discharging pipes, and point sources near industrial activities within the harbor. It is shown by principal component and cluster analyses that metal contamination was affected by a wide range of different and complex contamination mechanisms inside and outside the harbor, suggesting managing the pollution using straightforward strategies, i.e., solutions that only consider a single source or single pathway of metal emissions, is problematic.

Characterization of PAHs exposure in workplace atmospheres of a sinter plant and health-risk assessment for sintering workers

This study first measured concentrations of polycyclic aromatic hydrocarbons (PAHs) in four selected workplace atmospheres, including the raw materials inlet, sintering grate, rough roll shredder and control room, and the outdoor environment of a sinter plant. Then, PAHs exposures and their resultant health-risks were assessed for sintering workers. We found that total PAH concentrations of the three selected sintering process areas were higher than that of the control room. The above results could be explained by the filtration effect of the air conditioning device installed inside the control room. PAH homologue distributions of the three selected sintering process areas were significantly different from that of the outdoor environment suggesting that PAHs found in the sintering workplace atmospheres were mainly contributed by process fugitives. Total PAH exposure levels were lower than the current permissible exposure limits, thus revealing that sintering workers are not a high risk group for long-term effects attributable to PAHs. Moreover, the lung cancer risks associated with the above PAH exposures were lower than the significant risk level defined by US Supreme Court further confirming that their exposures could be acceptable at this stage.

Synthesis and characterization of three organic dyes with various donors and rhodanine ring acceptor for use in dye-sensitized solar cells

A series of new organic dyes comprising carbazole, iminodibenzyl, and phenothiazine moieties as the electron donors and rhodanine ring as the electron acceptor/anchoring groups were designed and developed for use in dye-sensitized solar cells. HOMO and LUMO energy level tuning was achieved by varying the carbazole, iminodibenzyls and phenothiazine donors. This was evidenced by spectral and electrochemical experiments and density functional theory calculations. Electrochemical studies indicated that the phenothiazine unit was much more effective in lowering the ionization potential than were the iminodibenzyl and carbazole units. The phenothiazine dye shows a solar-energy-to-electricity conversion efficiency (η) of 4.87%; the carbazole and iminodibenzyl dyes show η of 2.54% and 3.52%, respectively. These findings reveal that using carbazole, iminodibenzyl and phenothiazine donors as light-harvesting sensitizers are promising candidates for dye-sensitized solar cells.

Synthesis and characterization of protic ionic liquids containing cyclic amine cations and tetrafluoroborate anion

Several ionic liquids containing pyrrolidinium-, oxopyrrolidinium-, piperidinium-, morpholinium- and trialkylammonium-based cation are synthesized and their thermal property, refractive index, polarity, electrochemical property, and temperature dependency of dynamic viscosity, density and ionic conductivity are characterized. All tetrafluoroborate-based room temperature ionic liquids studied here have a high ionic conductivity (up to 31.4 mS cm−1). These ILs were successfully used as suitable electrolytes for the diffusion coefficient measurement of ferrocene. Absorbance solvatochromic probes Nile red is used to investigate the relative polarity of these ionic liquids and compared them with several organic solvents. The relation of fluidity to conductance is considered in terms of a Walden plot that is shown to provide a useful basis for organizing the applications of solvent media for “green” synthetic reactions.

Adsorption of CO2 from Flue Gas Streams by a Highly Efficient and Stable Aminosilica Adsorbent

ABSTRACT Three ordered mesoporous silicas (OMSs) with different pore sizes and pore architectures were prepared and modified with amine functional groups by a postgrafting method. The carbon dioxide (CO2) adsorption on these amine-modified OMSs was measured by using microbalances at 348 K, and their adsorption capacities were found to be 0.2–1.4 mmol g−1 under ambient pressure using dry 15% CO2. It was found experimentally that the CO2 adsorption capacity and adsorption rate were attributed to the density of amine groups and pore volume, respectively. A simple method is described for the production of densely anchored amine groups on a solid adsorbent invoking direct incorporation of tetraethylenepentamine onto the as-synthesized OMSs. Unlike conventional amine-modified OMSs, which typically show CO2 adsorption capacity less than 2 mmol g−1, such organic template occluded amine-OMS composites possessed remarkably high CO2 uptake of approximately 4.6 mmol g−1 at 348 K and 1 atm for a dry 15% CO2/nitrogen feed mixture. The enhancement of 8% in CO2 adsorption capacity was also observed in the presence of 10.6% water vapor. Durability tests done by cyclic adsorption-desorption revealed that these adsorbents also possess excellent stability. IMPLICATIONS Current available CO2 separation schemes for fossil fuel combustion normally invoke absorption by a liquid and are generally limited by the high capital and operation costs. Amine-modified solid sorbents are attractive for CO2 capture from flue gas streams because of the low energy consumption of the regeneration process. In this study, an easy method is developed by directly introducing tetraethylenepentamine onto the as-synthesized OMSs, which represents not only a time-saving route but also superior CO2 adsorption capacities and durability after repeated adsorption-desorption cycles, revealing some opportunities for future practical applications.

Enhancing the adsorption of vapor-phase mercury chloride with an innovative composite sulfur-impregnated activated carbon

Mercury chloride (HgCl(2)) is the major mercury derivate emitted from municipal solid waste incinerators, which has high risk to the environment and human health. This study investigated the adsorption of vapor-phase HgCl(2) with an innovative composite sulfurized activated carbon (AC), which was derived from the pyrolysis, activation, and sulfurization of waste tires. The composite sulfur-impregnation process impregnated activated carbon with aqueous-phase sodium sulfide (Na(2)S) and followed with vapor-phase elemental sulfur (S(0)). Thermogravimetric analysis (TGA) was applied to investigate the adsorptive capacity of vapor-phase HgCl(2) using the composite sulfurized AC. The operating parameters included the types of composite sulfurized AC, the adsorption temperature, and the influent HgCl(2) concentration. Experimental results indicated that the sulfur-impregnation process could increase the sulfur content of the sulfurized AC, but decreased its specific surface area. This study further revealed that the composite sulfurized AC impregnated with aqueous-phase Na(2)S and followed with vapor-phase S(0) (Na(2)S+S(0) AC) had much higher saturated adsorptive capacity of HgCl(2) than AC impregnated in the reverse sequence (S(0)+Na(2)S AC). A maximum saturated adsorptive capacity of HgCl(2) up to 5236 μg-HgCl(2)/g-C was observed for the composite Na(2)S+S(0) AC, which was approximately 2.00 and 3.17 times higher than those for the single Na(2)S and S(0) ACs, respectively.

Synthesis, Characterization and Photovoltaic Properties of Di-Anchoring Organic Dyes

Three new organic dyes comprising carbazole, iminodibenzyl and phenothiazine moieties, as electron donors and di-anchoring rhodanine rings as the electron acceptors, were synthesized and evaluated for use in dye-sensitized solar cells. A solar cell employing dye-containing phenothiazine as a hole-transporting unit and di-anchoring rhodanine rings as the electron acceptors exhibits a short circuit photocurrent density of 10.6 mA cm-2, an open-circuit voltage of 0.658 V and a fill factor of 0.7, corresponding to an overall conversion efficiency of 4.91% at standard AM 1.5 sunlight.

Polychlorinated dibenzo-p-dioxins/dibenzofuran mass distribution in both start-up and normal condition in the whole municipal solid waste incinerator.

Although many researches focused on the polychlorinated dibenzo-p-dioxins/dibenzofuran (PCDD/F) emissions from stack, in the bottom ash and in the surrounding environment, researches focused on PCDD/F mass distributions in the whole incineration plant have seldom been addressed. This study determined PCDD/F emissions in the whole plant. A high-resolution gas chromatograph/high-resolution mass spectrometer was utilized for analyzing 17 PCDD/F species. Experimental results displayed that PCDD/Fs were formed during fly ash from super heater (SH), economizer (EC), semi-dryer absorber (SDA) and fabric filter (FF) was transferred to fly ash pit. Mass distribution ratios of PCDD/Fs in g I-TEQ (Toxicity Equivalency Quantity) per week from stack, SH, EC, SDA, FF, generation and bottom residue (BR) in start-up operations were 14.6%, 0.1%, 8.3%, 1.0%, 41.7%, 33.4% and 0.9%, respectively. Above results indicated that main PCDD/F source in the MSWI was from fly ash. However, the fly ash is easily controlled and PCDD/F emitted from stack flue gases will be difficult to be handled. Therefore, we should pay more attention on PCDD/F emission from flue gases especially from start-up procedure. Besides, fly ash should be controlled by sodium hypophosphite before being landfilled. MSWI did require further detoxification treatments for the solid residues and flue gases.