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The gasification process of solid refuse fuel (SRF) releases tar and particulate pollutants in addition to many gaseous pollutants. This study investigated the effectiveness of pre-coating on a fabric filter for dust collection instead of a combined control process involving a wet scrubber and a bag filter. The powder layer composed of hydrated lime, wood char, or activated carbon contributed to reduce the blocking of the open pores of the fabric filter by tar and particulate matter. Among the three materials, hydrated lime was accumulated the most, resulting in a 0.7-mm coating thickness. The filter made of polyphenylene sulfide was the most effective in collection efficiency (86%) for the allowable pressure drop (60 mmH2O). Since a single filter with pre-coating is highly efficient, an oil scrubber with a removal efficiency of 2% to 3% is not essential. [ABSTRACT FROM AUTHOR]

The CO2 adsorption selectivity of plain activated carbon nanofibers (ANF) is generally low. For enhancement, nitrogen functionalities favorable for CO2 adsorption are usually tethered to the ANF. In the current study, we adopted chemical impregnation using 0.5 wt% tetraethylenepentamine (TEPA) solution as an impregnant. To enhance the impregnation of TEPA further, preliminary oxidation of the nanofibers with 70% HNO3 was conducted. The effects of HNO3 and TEPA treatments on the modified ANFs were investigated for physical (using N2 monosorb, thermogravimetric analyzer, scanning electron microscopy) and chemical (X-ray photoelectron spectrometer) changes. From the results, we found that although TEPA impregnation reduced the specific surface area and pore volume of the ANFs (from 673.7 and 15.61 to 278.8 m2/g and 0.284 cm3/g, respectively), whereas the HNO3 pre-oxidation increased the number of carboxylic groups on the ANF. Upon TEPA loading, pyridinic nitrogen was tethered and further enhanced by pre-oxidation. The surface treatment cumulatively increased the amine content from 5.81% to 13.31%. Consequently, the final adsorption capacity for low (0.3%) and pure CO2 levels were enhanced from 0.20 and 1.89 to 0.33 and 2.96 mmol/g, respectively. Hence, the two-step pre-oxidation and TEPA treatments were efficient for improved CO2 affinity. [ABSTRACT FROM AUTHOR]

Volatile organic compounds in the indoor environment of small businesses (painting workshops, hair salons, nail shops, printing shops, laundries etc.) may result in adverse health effects for both workers and customers. Similarly, VOCs identified in these small businesses are included in the list of ozone precursors that harm the environment. We used a non-thermal plasma reactor with gas recycling to study the decomposition of dilute concentrations of VOCs in air. The non-thermal plasma reactor was a surface dielectric barrier discharge (surface DBD) type, and the target gases were methyl ethyl ketone, toluene and n-hexane at concentrations of 20, 50 and 100 ppmv. Highest decomposition efficiency (97%) was achieved by treating n-hexane at 20 ppmv. Gas recycling had an almost negligible effect during pollutant treatment at varying recycling rates (0-50%). Increasing the input energy resulted in higher decomposition efficiency, but had an inverse effect on the energy yield of the system. Concentrations of CO2 and ozone increased linearly with the increase of energy input in the system. Consumption of ozone for other applications, such as water treatment or coupling the DBD system with an appropriate catalyst, may address this concern. [ABSTRACT FROM AUTHOR]

Heavy duty diesel vehicles deteriorate urban air quality by discharging a large volume of air pollutants such as soot and nitrogen oxides. In this study, a newly introduced auxiliary device a fuel activation device (FAD) to improve the combustion efficiency of internal engines by utilizing the cavitation effect was closely investigated by the fluid flow mechanism via a numerical analysis method. As a result, the FAD contributed to fuel atomization from the injection nozzle at lower inlet pressure by reducing the pressure energy. The improved cavitation effect facilitated fuel atomization, and ultimately reduced pollutant emission due to the decrease in fuel consumption. The axial velocity along the flow channel was increased 8.7 times with the aid of FAD, which improved the primary break-up of bubbles. The FAD cavitation effect produced 1.09-times larger turbulent bubbles under the same pressure and fuel injection amount than without FAD. [ABSTRACT FROM AUTHOR]

Controlled atomization is essential for reducing soot emission in practical diesel engines. In this work, an auxiliary device called a FAD (fuel activation device) was inserted into the fuel injection line to induce cavitation in the diesel spray. The performance of the FAD was examined in terms of pollutant emissions in a field test as well as aerosol sizes in lab-scale experiments. Experimental results showed that FAD reduced the size distribution of injected droplets and decreased the fuel consumption rate and emission amounts of PM10, CO, and NOx by 42%, 50% and 13.4%, respectively. [ABSTRACT FROM AUTHOR]

Zeolitic sorbents for CO adsorption were prepared from waste coal fly ash (FA) through hydrothermal treatment at various ratios of NaOH/FA and NaAlO/FA, including an initial alkali fusion step. The fusion step decomposed the fly ash into very small amorphous particulate zeolite forms. The fly ash was converted to Na-P1 type with a NaOH/FA ratio of 0.5 and Na-A type with a NaAlO/FA ratio of 0.53. The product properties were affected by the reaction temperature: Na-P1 and Na-A types were formed at 100°C. Temperatures above 140°C led to the formation of more sodalite because of the redissolving and recrystallization of zeolite crystals. Alkali metal and alkaline earth metal cations were impregnated in the synthesized Na-P1 and Na-A zeolite through an ion-exchange method. The completed zeolitic sorbents were applied to the adsorption of low-level CO. As a result of the experiments, calcium ions were found to be the best for CO adsorption owing to their electrostatic behavior and acid-base interaction. [ABSTRACT FROM AUTHOR]

Background: Massive intraluminal bleeding requires urgent intervention and management. However, the source of bleeding on the small intestine is difficult to determine. Intestinal tumor with intussusception is a rare and normally not an urgent condition. Herein, we present a rare case of intestinal intussusception with massive bleeding due to jejunal gastrointestinal stromal tumor (GIST) that required emergency surgical treatment. Case presentation: A 51-year-old male was admitted to the emergency department complaining of abdominal pain and acute hematochezia. Esophagogastroduodenoscopy (EGD) and colonoscopy could not determine the source of the bleeding site. Abdominal pelvic computed tomography (AP-CT) revealed GIST with intussusception, strongly suggestive of distal jejunal bleeding. Unresponsive transfusion with low blood pressure and continuous hematochezia led to emergency laparotomy. GIST, which was the leading point for intussusception, was located in the jejunum and showed mucosal ulceration of approximately 3.5 cm in diameter. Following resection and functional anastomosis, histology revealed a GIST with low mitotic count (< 5 per 50HPF). Moreover, immunochemical analysis revealed positivity for c-kit (CD117) and DOG-1. There were no complications 2 months after surgery. Conclusions: Intussusception associated with GIST is a rare finding that can be life-threatening if it occurs with an ulcer. This case showed that the early detection of bleeding and emergency surgery could prevent severe complications. [ABSTRACT FROM AUTHOR]