David Ramirez

Measurement of Ultrafine Particles and Other Air Pollutants Emitted by Cooking Activities

Cooking emissions show a strong dependence on cooking styles and parameters. Measurements of the average ultrafine particle (UFP) concentration, PM2.5 and black carbon concentrations emitted by cooking activities ranged from 1.34 × 104 to 6.04 × 105 particles/cm3, 10.0 to 230.9 μg/m3 and 0.1 to 0.8 μg/m3, respectively. Lower UFP concentrations were observed during boiling, while higher levels were emitted during frying. The highest UFP concentrations were observed when using a gas stove at high temperature with the kitchen exhaust fan turned off. The observed UFP profiles were similar in the kitchen and in another room, with a lag of approximately 10 min.

Roadside Measurements of Ultrafine Particles at a Busy Urban Intersection

Abstract A field sampling campaign on ultrafine particles (UFPs, diameter <100 nm) was conducted at a busy traffic intersection from December 2006 to June 2007 in Corpus Christi, TX. This traffic intersection consisted of South Padre Island Drive (SPID, Highway 358) and Staples Street. Traffic densities on SPID were 9102/hr and 7880/hr for weekdays and weekends, respectively. Staples Street traffic densities were 2795/hr and 2572/hr, respectively. There were approximately 3.7% heavy-duty diesel vehicles (HDDVs) on both roadways. Peak traffic flows occurred early in the morning and late in the evening during weekdays and around noon on weekends. The average UFP total number concentration collected by a condensation particle counter (CPC 3785; TSI) was 66 × 103 cm−3. A direct relationship between the UFP number concentration and traffic density was observed, but the HDDV traffic density was found to be a better estimator of the UFP number concentration than total traffic density. A scanning mobility particle sizer (SMPS 3936 with DMA 3081 and CPC 3785, TSI) measuring the particle size distribution from 7 to 290 nm was rotated among four corners of the intersection. The upwind and downwind size distributions were both bimodal in shape, exhibiting a nucleation mode at 10 –30 nm and a secondary mode at 50 –70 nm. The highest and lowest particle concentrations were observed on the downwind and upwind sides of both roadways, respectively, indicating the importance of wind direction. Wind speed also played an important role in overall particle concentrations; UFP concentrations were inversely proportional to wind speed. A negative correlation was observed between particle number concentrations and ambient temperature. The particle number concentration was 3.5 times greater when traffic was idling at a red light than moving at a green light.

Gas-phase formaldehyde adsorption isotherm studies on activated carbon: Correlations of adsorption capacity to surface functional group density

Formaldehyde (HCHO) adsorption isotherms were developed for the first time on three activated carbons representing one activated carbon fiber (ACF) cloth, one all-purpose granular activated carbon (GAC), and one GAC commercially promoted for gas-phase HCHO removal. The three activated carbons were evaluated for HCHO removal in the low-ppm(v) range and for water vapor adsorption from relative pressures of 0.1-0.9 at 26 °C where, according to the IUPAC isotherm classification system, the adsorption isotherms observed exhibited Type V behavior. A Type V adsorption isotherm model recently proposed by Qi and LeVan (Q-L) was selected to model the observed adsorption behavior because it reduces to a finite, nonzero limit at low partial pressures and it describes the entire range of adsorption considered in this study. The Q-L model was applied to a polar organic adsorbate to fit HCHO adsorption isotherms for the three activated carbons. The physical and chemical characteristics of the activated carbon surfaces were characterized using nitrogen adsorption isotherms, X-ray photoelectron spectroscopy (XPS), and Boehm titrations. At low concentrations, HCHO adsorption capacity was most strongly related to the density of basic surface functional groups (SFGs), while water vapor adsorption was most strongly influenced by the density of acidic SFGs.

Comparative study of carbon nanotubes and granular activated carbon: Physicochemical properties and adsorption capacities

The overall goal was to determine an optimum pre-treatment condition for carbon nanotubes (CNTs) to facilitate air pollutant adsorption. Various combinations of heat and chemical pre-treatment were explored, and toluene was tested as an example hazardous air pollutant adsorbate. Specific objectives were (1) to characterize raw and pre-treated single-wall (SW) and multi-wall (MW) CNTs and compare their physical/chemical properties to commercially available granular activated carbon (GAC), (2) to determine the adsorption capacities for toluene onto pre-treated CNTs vs. GAC. CNTs were purified via heat-treatment at 400 °C in steam, followed by nitric acid treatment (3N, 5N, 11N, 16N) for 3-12 h to create openings to facilitate adsorption onto interior CNT sites. For SWNT, Raman spectroscopy showed that acid treatment removed impurities up to a point, but amorphous carbon reformed with 10h-6N acid treatment. Surface area of SWNTs with 3 h-3N acid treatment (1347 m(2)/g) was higher than the raw sample (1136 m(2)/g), and their toluene maximum adsorption capacity was comparable to GAC. When bed effluent reached 10% of inlet concentration (breakthrough indicating time for bed cleaning), SWNTs had adsorbed 240 mg/g of toluene, compared to 150 mg/g for GAC. Physical/chemical analyses showed no substantial difference for pre-treated vs. raw MWNTs.

Introduction to Environmental Sustainability Issues in the South Texas–Mexico Border Region

Due to the importance of the Rio Grande in providing water to this semi-arid ecoregion and the major farming areas and cities along its banks, studies are being done to help assure the safety of the water flowing in the river. Studies are also being done along the coastal regions to monitor the lagoons and inland waterways connected with the Gulf of Mexico. Water pollution can come from runoff from irrigation and rain as well as from discharge from the factories located along the waterways, feeder creeks, and rivers. Air pollution comes from the factories on both sides of the Rio Grande, along the coast where refineries and other industries are located near the ports, and from dirt being carried by strong winds from farmland and the sand dune areas. Dust also comes from other parts of the world as has been seen with dust storms originating in the Sahara that propel the dust into the jet stream which then drops the dust over this region. The chapters within this book focus on air and water pollution along the Rio Grande, its watershed, and the coastal region due to the fragile ecology of the region.

Analysis and comparison of inertinite-derived adsorbent with conventional adsorbents

To increase U.S. petroleum energy-independence, the University of Texas at Arlington (UT Arlington) has developed a coal liquefaction process that uses a hydrogenated solvent and a proprietary catalyst to convert lignite coal to crude oil. This paper reports on part of the environmental evaluation of the liquefaction process: the evaluation of the solid residual from liquefying the coal, called inertinite, as a potential adsorbent for air and water purification. Inertinite samples derived from Arkansas and Texas lignite coals were used as test samples. In the activated carbon creation process, inertinite samples were heated in a tube furnace (Lindberg, Type 55035, Arlington, UT) at temperatures ranging between 300 and 850 °C for time spans of 60, 90, and 120 min, using steam and carbon dioxide as oxidizing gases. Activated inertinite samples were then characterized by ultra-high-purity nitrogen adsorption isotherms at 77 K using a high-speed surface area and pore size analyzer (Quantachrome, Nova 2200e, Kingsville, TX). Surface area and total pore volume were determined using the Brunauer, Emmet, and Teller method, for the inertinite samples, as well as for four commercially available activated carbons (gas-phase adsorbents Calgon Fluepac-B and BPL 4 × 6; liquid-phase adsorbents Filtrasorb 200 and Carbsorb 30). In addition, adsorption isotherms were developed for inertinite and the two commercially available gas-phase carbons, using methyl ethyl ketone (MEK) as an example compound. Adsorption capacity was measured gravimetrically with a symmetric vapor sorption analyzer (VTI, Inc., Model SGA-100, Kingsville, TX). Also, liquid-phase adsorption experiments were conducted using methyl orange as an example organic compound. The study showed that using inertinite from coal can be beneficially reused as an adsorbent for air or water pollution control, although its surface area and adsorption capacity are not as high as those for commercially available activated carbons. Implications: The United States currently imports two-thirds of its crude oil, leaving its transportation system especially vulnerable to disruptions in international crude supplies. UT Arlington has developed a liquefaction process that converts coal, abundant in the United States, to crude oil. This work demonstrated that the undissolvable solid coal residual from the liquefaction process, called inertinite, can be converted to an activated carbon adsorbent. Although its surface area and adsorption capacity are not as high as those for commercially available carbons, the inertinite source material would be available at no cost, and its beneficial reuse would avoid the need for disposal. Supplemental Materials: Supplemental materials are available for this article. Go to the publishers online edition of the Journal of the Air & Waste Management Association for properties of the commercial activated carbons tested in this study.

Surface Modified Multi-walled Carbon Nanotubes: Preparation and BinarySystem Dye Removal

Surface modification of multiwalled carbon nanotube (CNT) using sodium dodecyl sulfate (SDS) was studied in this paper. The surface modified CNT (CNT-SDS) was used to remove dyes from single and binary systems. The surface characteristics of CNT-SDS were investigated using Fourier transforms infrared (FTIR) and scanning electron microscopy (SEM). Basic Blue 41 (BB41) and Basic Red 18 (BR18) were used as model dyes. The kinetic of dye removal from single and binary systems using CNT-SDS was studied. The kinetic of dye adsorption onto CNT-SDS followed pseudo-second order model for both systems. The Langmuir and Freundlich isotherm models were applied to experimental data of single systems and the isotherm constants were calculated. The adsorption capacities of CNT and CNT-SDS for BB41 and BR18 were 90 and 80, 185 and 135 mg/g, respectively. The results showed that the CNTSDS as an adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored wastewater.

Environmental Sustainability Issues in the South Texas–Mexico Border Region

Due to the importance of the Rio Grande in providing water to this semi-arid ecoregion and the major farming areas and cities along its banks, studies are being done to help assure the safety of the water flowing in the river. Studies are also being done along the coastal regions to monitor the lagoons and inland waterways connected with the Gulf of Mexico. Water pollution can come from runoff from irrigation and rain as well as from discharge from the factories located along the waterways, feeder creeks, and rivers. Air pollution comes from the factories on both sides of the Rio Grande, along the coast where refineries and other industries are located near the ports, and from dirt being carried by strong winds from farmland and the sand dune areas. Dust also comes from other parts of the world as has been seen with dust storms originating in the Sahara that propel the dust into the jet stream which then drops the dust over this region. The chapters within this book focus on air and water pollution along the Rio Grande, its watershed, and the coastal region due to the fragile ecology of the region. H. Lamm (*) TAMUS LSAMP Project, Texas A&M Engineering Experiment Station, College Station, TX 77845-3470, USA e-mail: hlamm@tamu.edu D. Ramirez Department of Environmental Engineering, Frank H. Dotterweich College of Engineering, Texas A&M University-Kingsville, Kingsville, TX 78363, USA Center for Research Excellence in Science and Technology – Research on Environmental Sustainability of Semi-Arid Coastal Areas (CREST-RESSACA), Texas A&M University-Kingsville, Kingsville, TX 78363, USA J. Ren Department of Environmental Engineering, Frank H. Dotterweich College of Engineering, Texas A&M University-Kingsville, Kingsville, TX 78363, USA D. Ramirez et al. (eds.), Environmental Sustainability Issues in the South Texas–Mexico Border Region, DOI 10.1007/978-94-007-7122-2_1,

Manufacture and Physical Characterization of Wood-Derived Activated Carbon from South Texas Mesquite for Environmental Applications

Activated carbons are widely used to remove contaminants from waste streams. Desirable properties of activated carbon include large surface area, porosity, high degree of selectivity between contaminant and carrier medium, rapid transport of the contaminant from bulk stream to the internal porous structure of the adsorbent, high adsorption capacity at low contaminant concentration, and available commercially at competitive prices. This research focuses on the production and physical characterization of carbonaceous adsorbents from low cost mesquite woodchips available in the South Texas region. Activated carbons were prepared from mesquite woodchips in a bench-scale tubular reactor. Steam and a potassium carbonate solution were used for the physical and chemical activation methods to manufacture activated carbons. The activated carbons were then characterized in terms of their physical and adsorption capacities for nitrogen at 77 K and methanol and water vapor at ambient temperature. The surface areas of the samples were determined using the N2-Brunauer-Emmett-Teller method. The percent yield, bulk density, pore size distribution, average pore width, and total pore volume were evaluated. Equilibrium adsorption capacities of methanol and water vapor were determined by a gravimetric method. Experimental adsorption capacity data were in agreement with the Freundlich and Langmuir adsorption models.