Synthesis and characterization of FSB@Fe3O4 composites and application in removal of indigo carmine dye from industrial wastewaters

Environmental Science and Pollution Research - The syntheses and characterization of fish scale biochar magnetic composites (FSB@Fe3O4) and their applications in the removal of indigo carmine dye...     

Ambient and Source SO2 Detector Based on a Fluorescence Method

The principle of this detector is based on the measurement of the intensity of the ultraviolet fluorescence of SO₂ produced by absorption of the Zn 2138 Å or Cd 2288 Å line. The fluorescence intensity was found to be linear from 0.1 to 500 ppm of SO₂ in air with the Zn lamp and from 0.1 to 1600 ppm with the Cd lamp. The detection limit at present is about 20 ppb. There is no detectable interference from O₃, H₂S, NO₂, CO₂, CO, or H₂, although the presence of a large concentration of CS₂ (500 times as much as SO₂) NO (500 times) or C₂H₄ (4000 times) interferes with the measurement. The presence of 2% H₂0 reduces the signal by 25%, while up to 1 % CH₄ has almost no effect.     

Mapping and Eradication Prioritization Modeling of Red Sesbania (Sesbania punicea) Populations

Red sesbania is an invasive South American shrub that has rapidly expanded its range along California waterways, emphasizing the need to prioritize eradication sites at a regional scale. To accomplish this, we updated baseline location data in summer 2010 using field surveys throughout the state. We collected relevant GPS attribute data for GIS analysis and eradication prioritization modeling. The regional survey identified upstream and downstream extents for each watershed, as well as outliers in urban areas. We employed the Weed Heuristics: Invasive Population Prioritization for Eradication Tool (WHIPPET) to prioritize red sesbania sites for eradication, and revised the WHIPPET model to consider directional propagule flow of a riparian species. WHIPPET prioritized small populations isolated from larger infestations, as well as outliers in residential areas. When we compared five experts’ assessments of a stratified sample of the red sesbania populations to WHIPPET’s prioritization results, there was a positive, but nonsignificant, correlation. The combination of WHIPPET and independent expert opinion suggests that small, isolated populations and upstream source populations should be the primary targets for eradication. Particular attention should be paid to these small populations in watersheds where red sesbania is a new introduction. The use of this model in conjunction with evaluation by the land manager may help prevent the establishment of new seed sources and protect uninfested riparian corridors and their adjacent watersheds.     

The Exposure to Carbon Monoxide of Occupants of Vehicles Moving in Heavy Traffic

Carbon monoxide and hydrocarbons were sampled at operator’s nose height inside vehicles moving in moderate to heavy traffic in six cities. The samples were integrated over 20-30 minutes by collection in Mylar bags. Carbon monoxide and hydrocarbons were analyzed by infrared and flame ionization, respectively, with instruments at the Continuous Air Monitoring Program (CAMP) station in each city. Detector tubes for carbon monoxide were also used to determine 5-min concentrations at suspected high points in the field. Estimates of traffic density were made. Three types of traffic arteries were considered: (7) heavily traveled, wide expressways, (2) main city streets with moderately rapid vehicular traffic, and (3) center city streets with slow-moving traffic. Integrated half-hour CO concentrations obtained within the vehicles while in traffic were generally considerably higher than the concurrent concentrations measured at the CAMP sites. In-traffic CO values in all cities sampled exceeded 30 ppm in at least 10% of the integrated samples. The range of city averages was 21–39 ppm carbon monoxide and the range of individual integrated samples was 7–77 ppm of carbon monoxide.     

The Role of Pressure Drop and Flow Redistribution on Modeling Mercury Control Using Sorbent Injection in Baghouse Filters

Abstract

A mathematical model based on simple cake filtration theory was coupled to a reviously developed two-stage mathematical model for mercury (Hg) removal using powdered activated carbon injection upstream of a bag-house filter. Values of the average permeability of the filter cake and the filter resistance extracted from the model were 4.4× 10^?13 m² and 2.5 ×10^?4 m^?1, respectively. The flow is redistributed during partial cleaning of the filter, with flows higher across the newly cleaned filter section. The calculated average Hg removal efficiency from the baghouse is lower because of the high mass flux of Hg exiting the filter in the newly cleaned section. The model shows that calculated average Hg removal is affected by permeability, filter resistance, fraction of the baghouse cleaned, and cleaning interval.     

Material flows in the life cycle of leather

This paper presents a study on the resource and environmental profile of leather for communicating to the consumers about the environmental burdens of leather products. The results indicate that significant environmental impacts were caused during the tanning and finishing of leather as well as the electricity production and transportation required in the life cycle. The use of fossil fuels in the production of energy has greater impact with increased emissions leading to about 15190 kg CO₂ equivalent of global warming and about 73 kg SO₂ equivalent of acidification while producing 100 m² of leather for shoe uppers. Further resource use of 174 kg of coal, 6.5 kg of fuel oil, 17.4 m³ of water and 348 kg of chemicals of which about 204 kg are hazardous are consumed, and wastewater of about 17 m³, BOD of 55 kg, COD of about 146 kg, TDS of 732 kg and solid waste of about 1445 kg are generated during the life cycle for the production of 100 m² of leather. The total solid waste generated is 1317 kg, out of which about 80% is biodegradable contributed by slaughtering, tanning and finishing stage, 14% is non-biodegradable contributed by tanning, finishing and electricity production stages and 6% is hazardous mainly from tanning and finishing stage of leather.     

Managing Asia's environmental crisis: EQM opportunities for remediation and technology transfer

Conditions of environmental pollution and degradation in Asia are among the worst in the world. Rapid economic growth and industrialization over the past half century have accelerated the pollution of air, water, and land resources in a region with the world's largest concentration of population. As the economics of Asia recover from financial crisis in the late 1990s, they will face a more serious environmental crisis in the early years of the 21st century. Remediation of soil and water contamination will become a stronger concern in the region, as the human health impacts become more visible and widespread. Although environmental remediation is only beginning to emerge in Asia as a solution to problems of natural resource degradation, the authors show how U.S. firms with experience in quality environmental management and biological remediation technologies will find new opportunities for exports and technology transfer. Environmental technology and services firms interested in Asia must understand both the opportunities for and barriers to operating in Asia.     

Evaluation of natural attenuation at a 1,4‐dioxane‐contaminated site

1,4‐Dioxane entered the environment as a result of historic leaks and spills in the production area at an industrial facility in the southeastern coastal plain. The areal extent of the 1,4‐dioxane plume is several hundred acres and is largely contained on the site. Land use adjacent to the plant property is primarily undeveloped (wetlands or woods) or industrial, with a small area of mixed land use (commercial/residential) to the southwest and north. The surficial aquifer is a relatively simple hydrogeologic system with well‐defined boundaries and is comprised of a 50‐ to 70‐foot‐thick deposit of alluvial/fluvial sand and gravel that overlies an aquitard in excess of 100 feet thick. A groundwater flow model, developed and calibrated using field‐measured data, was used for the fate‐and‐transport modeling of 1,4‐dioxane. The flow‐and‐transport model, combined with the evaluation of other site geochemical data, was used to support the selection of monitored natural attenuation (MNA) as the proposed groundwater remedy for the site. Since the active sources of contamination have been removed and the modeling/field data demonstrated that the plume was stable and not expanding, the proposed MNA approach was accepted and approved by the regulatory agency for implementation in 2004. Subsequent accumulated data confirm that concentrations in the 1,4‐dioxane plume are declining as predicted by the fate‐and‐transport modeling. © 2008 Wiley Periodicals, Inc.