Physical,Mechanical, and Morphological Characteristics of Extruded Starch Acetate Foams

Starch acetates with degrees of substitution (DS) of 0.57, 1.11, 1.68, and 2.23 were prepared and extruded with either water or ethanol. The microstructure, physical properties (radial expansion ratio [RER] and unit density), mechanical properties (spring index [SI] and compressibility), and crystalline structure of the foams were investigated. The functional properties were a function of DS and blowing agent type. When water was used as the blowing agent and DS increased, the foams were pale yellow, with rough and uneven surfaces. The cells were dense, with thick cell walls. Lower RER and SI, with higher DS, were associated with high unit density and compressibility. When ethanol was used as the blowing agent, contrary results were observed. The snow-white foams had smooth surfaces, uniform cells, and smooth cell walls. High RER and SI, and low unit density and compressibility were observed. The changes in SI and compressibility with RER also were examined and found to depend on the type of solvent. A crystalline pattern was observed because of the formation of well-ordered structures during extrusion.     

Behavior of As,Cd, Co,Cr, Cu,Pb, Ni,and Zn at the soil/plant interface around an uncontrolled landfill (Casablanca,Morocco)

The present work undertaken in the environmental context aims to study the distribution of heavy metals in plants that grow naturally around uncontrolled landfills. The study's goal was to identify plants that can be used to remediate contaminated soils. For this purpose, 14 plants species and their rhizospheric soil samples were collected and analyzed for arsenic, cadmium, cobalt, chromium, copper, lead, nickel, and zinc by inductively coupled plasma‐atomic emission spectrometry. The results showed the presence of elevated metal concentrations in soil, many exceeding the regulatory values, and that many species exhibited an ability to accumulate multiple metals in their shoots and roots without sustaining toxicity. This was confirmed by bioconcentration and translocation factors generally higher than 1.     

Behaviour of Cd,Cr, Mn,Ni, Pb,and Zn in sewage sludge incineration by fluidised bed furnace

Cd, Cr, Mn, Ni, Pb, and Zn behaviour during sewage sludge incineration was investigated in seven pilot tests using a circulating fluidised bed furnace. Dewatered sludge at a solids concentration of 15-18% was fed to the furnace either alone (two tests) or spiked with chlorinated organic compounds (five tests). The behaviour of metals in the fluidised bed furnace was studied by comparing metal concentrations in the two main ash streams: ash separated from the cyclone immediately following the fluidised bed furnace, and fly ash recovered in the final bag filter. A metal enrichment factor was defined as the ratio of metal concentration between filter ash and cyclone ash. Only Cd and Pb showed any significant enrichment. Their enrichment factors were mainly affected by chlorine concentration in the feed sludge. To check whether simple equilibrium models may explain and predict metal behaviour, experimental data were compared with percentage of the metal vaporisation in the combustion chamber predicted using a thermodynamic model. Discrepancies between model predictions and experimental results are accounted for by considering that kinetics may be a limiting factor in the formation of metal chloride gaseous species. Due to the very short sludge residence time in the fluidised bed furnace, the gaseous compounds have little chance to evolve completely.     

Outdoor Weathering Evaluation of Carbon-Black-Filled, Biodegradable Copolyester as Substitute for Traditionally Used, Carbon-Black-Filled, Nonbiodegradable, High-Density Polyethylene Mulch Films

Carbon-black-filled, biodegradable, copolyester mulch film (Eastar®, or EA, Tennessee Eastman, Kingsport, TN) and commercial carbon-black-filled, high-density polyethylene (HDPE) mulch film were exposed for 12 weeks to commercial vegetable crop growing conditions by being placed directly on irrigated soil in the field of the University of Tennessee Alcoa Highway State Agriculture Experiment Station (Knoxville, TN) and by being placed on a plywood exposure rack as described by the American Society of Testing and Materials (ASTM) Standard Test Method 1435: Outdoor Weathering of Plastics. Mechanical properties and weather information were collected in order to evaluate the feasibility of using the newly developed biodegradable EA mulch film to replace the nonbiodegradable HDPE mulch film. Results indicate that the EA mulch film exhibited favorable tensile strength and elongation-at-break during outdoor exposure rack testing and outdoor, in-field, placed directly on the soil, exposure testing, suggesting biodegradable EA could be a substitute for the HDPE nonbiodegradable material.     

Extruded Cornstarch-Glycerol-Polyvinyl Alcohol Blends: Mechanical Properties, Morphology, and Biodegradability

Elongation properties of extruded cornstarch were improved by blending with glycerol. Further blending of starch-glycerol with polyvinyl alcohol (PVOH) resulted in significant improvements in both tensile strength (TS) and elongation at break. Samples of starch-glycerol without PVOH equilibrated at 50% relative humidity had a TS of 1.8 MPa and elongation of 113%, whereas those containing PVOH had a TS and elongation of 4 MPa and 150%, respectively. Dynamic mechanical analysis (DMA) of starch-glycerol-PVOH blends showed that decreases in glass transition temperatures (T _g values) were proportional to glycerol content. Scanning electron microscopy (SEM) of fractured surfaces revealed numerous cracks in starch-glycerol (80:20) samples. Cracks were absent in starch-glycerol (70:30) samples. In both blends, many starch granules were exposed at the surface. No exposed starch granules were visible in blends with added PVOH. Starch-glycerol samples incubated in compost lost up to 70% of their dry weight within 22 days. Addition of PVOH lowered both the rate and extent of biodegradation.     

Stabilization of As, Cr, Cu, Pb and Zn in soil using amendments--a review

The spread of contaminants in soil can be hindered by the soil stabilization technique. Contaminant immobilizing amendments decrease trace element leaching and their bioavailability by inducing various sorption processes: adsorption to mineral surfaces, formation of stable complexes with organic ligands, surface precipitation and ion exchange. Precipitation as salts and co-precipitation can also contribute to reducing contaminant mobility. The technique can be used in in situ and ex situ applications to reclaim and re-vegetate industrially devastated areas and mine-spoils, improve soil quality and reduce contaminant mobility by stabilizing agents and a beneficial use of industrial by-products. This study is an overview of data published during the last five years on the immobilization of one metalloid, As, and four heavy metals, Cr, Cu, Pb and Zn, in soils. The most extensively studied amendments for As immobilization are Fe containing materials. The immobilization of As occurs through adsorption on Fe oxides by replacing the surface hydroxyl groups with the As ions, as well as by the formation of amorphous Fe(III) arsenates and/or insoluble secondary oxidation minerals. Cr stabilization mainly deals with Cr reduction from its toxic and mobile hexavalent form Cr(VI) to stable in natural environments Cr(III). The reduction is accelerated in soil by the presence of organic matter and divalent iron. Clays, carbonates, phosphates and Fe oxides were the common amendments tested for Cu immobilization. The suggested mechanisms of Cu retention were precipitation of Cu carbonates and oxy-hydroxides, ion exchange and formation of ternary cation-anion complexes on the surface of Fe and Al oxy-hydroxides. Most of the studies on Pb stabilization were performed using various phosphorus-containing amendments, which reduce the Pb mobility by ionic exchange and precipitation of pyromorphite-type minerals. Zn can be successfully immobilized in soil by phosphorus amendments and clays.     

Health risk assessment of heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in circumjacent soil of a factory for recycling waste electrical and electronic equipment

The aim of the study was to determine the potential environmental contamination in a typical factory for recycling waste electrical and electronic equipment in Shanghai. Heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in the soil around the factory have been evaluated in this paper. Compared with the background value, the concentrations of six metals detected in all the samples were higher, which showed that toxic metals were released into soil around the factory. Compared with the Environmental Quality Standards for Soils, China grade III, all the six metals are under soil guidelines. The non-cancer risk in different directions from the factory was in the order of: the north > the west > the south > the east. For inhalation and ingestion, the non-cancer risk in the soil west of the factory was biggest. Nevertheless, the non-cancer risk in the soil north of the factory was the biggest for dermal contact. The trend of cancer risk was the west > the south > the north > the east. The non-cancer risk and the carcinogenic risk for Cr, Ni, and Cd were all below the limiting value. This study might provide a reference for the risk assessment involved in electronic waste management and recycling activities.     

Analysis of the recycling system for aluminum cans,focusing on collection,transportation, and the intermediate processing methods

In this article, the systems for the collection and intermediate processing of used beverage cans (UBCs) are compared and analyzed, focusing on the time taken and the cost of processing, the energy consumption, and the emissions of CO₂, SO _x , and NO _x , during the process. We found that cases where the UBCs were crushed in the discharging process gave better results, and how the UBCs were collected was the most important factor. It was more desirable to treat UBCs in one place than in two places. When the transportation distance was longer, the pressed form of UBCs was more convenient. When the transportation distance was short, the original form, the crushed form, and the shredded form of UBCs were all suitable. That is, the contribution of the transportation process to the evaluation was large when the transport distance was long, and the contribution of the treatment process was large when the transport distance was short.     

Applied geologic,microbiological, and engineering constraints of in-situ BTEX bioremediation

An in-situ bioremediation project has been designed and constructed for a site in south-central Kansas just north of Wichita. A pipeline leaked an unknown quantity of refinedfuels in the 1970s. The spill was undetected until hydrocarbons were found in a nearby municipal water supply well. Of concern, from a regulatory perspective, are the alkylbenzene components found in the groundwater, including benzene, toluene, ethylbenzene, and xylene (BTEX). Initial abatement procedures, including free product removal and pumping, had become ineffective. In-situ bioremediation was selected to complete the restoration process. The project emphasizes the need for a strong understanding of the geologic and hydrogeologic conditions prevalent under the site. Site studies were conducted to determine the distribution and mass of the contaminant and the hydraulic regime. Laboratory microbial studies were used to determine the efficacy of nitrate as a primary electron acceptor. Information from site studies was used to design a treatment system tailored to the requirements of the site. The treatment system is designed to deliver the maximum amount of nutrient-enriched water to the contaminated zone while maintaining hydraulic control of the site.     

Arsenic,cadmium, lead and thallium in coal ash from individual household furnaces

52 coal ash samples from individual households were analyzed to determine the pH and the concentrations of four toxic elements: arsenic, cadmium, lead and thallium. The method used was atomic absorption spectrometry with graphite-furnace atomization. The ash samples originated from various coal grades and statistical analysis showed existing correlations between the concentrations of studied elements, pH and the coal grades. The maximum concentrations of arsenic, cadmium, lead and thallium were 50,900, 43,500, 128,900, and 6660 µg/kg, respectively. The results were compared with the published data for the ash of industrial origin.

     

Rheology,Morphology, Crystallization Behaviors,Mechanical and Thermal Properties of Poly(lactic acid)/Polypropylene/Maleic Anhydride-Grafted Polypropylene Blends

The rheologies, morphologies, crystallization behaviors, mechanical and thermal properties of poly(lactic acid) (PLA)/polypropylene (PP) blends and PLA/PP/maleic anhydride-grafted PP (MAPP) blends were investigated. The results showed that the complex viscosities of PLA/PP blends were between those of neat PLA and neat PP, and MAPP had a thinning effect on those of the blends. PLA/PP blends exhibited the distinct phase separation morphologies due to the limited partial miscibility of the blend components. MAPP slightly improved the miscibility between PLA and PP. Both the cold crystallization of PLA component and melt crystallization of PP component were enhanced, probably because PLA and PP were reciprocal nucleating agents. The tensile strength and flexural modulus decreased, while the tensile strain at break and heat deflection temperature (HDT) increased with the increasing PP content. MAPP had the positive effects on the notched impact strength and HDT of PLA-rich blends and also increased the flexural modulus of the binary blends. The thermal stability of the blend was improved by PP, and the incorporation of MAPP further enhanced the thermal stability.     

Trends in Fish Community Structure,Biomass, and Production in Three Algoma,Ontario, Lakes

Long-term (i.e. >10 years) whole community fish dataincluding catch-per-unit-effort, abundance, biomass, andproduction from three lakes were used: 1) to examine variabilityin fish population and community measures among years using wholelake assessments of fish populations derived from mark recaptureexperiments, 2) to assess implications arising from monitoringindividual species vs. the whole fish community, and 3) toascertain whether, in fisheries assessments (science) a commonlyused surrogate measure, [catch-per-unit-effort (CPUE)] reflectedannual changes in the fish assemblage, and thus may be a goodestimator of abundance. High, long-term variability was evident in the abundance andbiomass of a fish species in our lakes, yet the communityremained relatively stable in terms of its biomass andproduction. Changes in total fish community biomass appear drivenby large species, which, relative to small fish species, remainstable among years. Among years, species richness remainedstable; however, fish species changed in the community. AnnualCPUE was found to be a suitable surrogate for abundance (N) ofsmall fishes; CPUE x mean weight of the catch (bCPUE) was asuitable surrogate for biomass (B) of large fishes. Prior toconcluding that a change in a fish population has occurred as aresult of a stressor, care must be taken to critically examinethe level of population assessment in order to avoid acceptingpotentially invalid conclusions.     

Biodegradability of Thermally Aged PHB,PHB-V,and PCL in Soil Compostage

The biodegradability of poly--hydroxybutyrate (PHB), poly--hydroxybutyrate-co-valerate (PHB-V) and poly--caprolactone (PCL) were examined following thermal aging in an oven for 192, 425 and 600 h. Different temperatures, 100, 120 and 140°C for PHB and PHB-V and 30, 40 and 50^oC for PCL were used to assess the influence of this parameter on biodegradation. The biodegradability tests were done in soil compostage at pH 11.0 and involved measuring the residual mass of polymer. Thermal analysis of the polymers was done using a differential scanning calorimeter (DSC). The melting temperature and crystallinity were also determined. Thermal ageing increased the biodegradability only for PHB at 120 and 140^oC, and there was no correlation between crystallinity and the biodegradation of the polymers.     

In-Situ Fenton-Like Oxidation of Volatile Organics: Laboratory,Pilot, and Full-Scale Demonstrations

Laboratory, pilot, and full-scale experiments were used to evaluate and optimize the ISOTEC^SM remedial process at a warehousing facility in Union, New Jersey. Based on modified Fenton's oxidative chemistry, the ISOTEC^SM process uses a proprietary catalytic agent that delays formation of reactive hydroxyl radicals. This allows adequate dispersion of the hydroxyl radicals, which is an oxidizing agent, throughout a contaminant plume. Ground-water at the site was contaminated with high levels of gasoline and waste oil constituents, principally BTEX and MTBE. Bench scale microcosm studies were used to evaluate the appropriate site-specific stoichiometric relationships between catalyst, stabilizers, and oxidizers; the effect of contaminant type and concentration; and the pH optima. Based on results of the laboratory studies, a pilot-scale study was performed at the site. One injection point for catalyst, stabilizers, and oxidant was installed in the contaminated zone at the site, with one hydraulically connected downgradient well used for monitoring. A single treatment of the reagents in the optimal stoichiometry determined from the laboratory study was injected in-situ over a period of three days. A 98.5 percent reduction in volatile organics was observed in the area treated, with the radial extent of treatment estimated to be approximately 20 feet, based on the presence of hydroxyl radicals detected in hydraulically connected areas and at the surface. The full-scale process employed six injection points and three treatment cycles over a three-month period. Subsequent to treatment, contaminant levels were either nondetectable or were reduced to below applicable New Jersey groundwater standards, with regulatory closure on the site achieved in less than one year.     

PM10, O3, CO Concentrations and Elemental Analysis of Airborne Particles in a School Building

Measurements of indoor and outdoor PM10, as well as indoor O₃ and CO concentrations were conducted and are presented here. These measurements were carried out at an institute building, located in a suburban industrial area in Greece. Both indoor and outdoor PM10 samples were also collected and their elemental composition was identified by ED-XRF analysis. Twenty seven major, minor and trace elements were identified. The measurements took place generally in different periods of institute operation, from June 2004 to February 2005. The indoor PM10 concentrations which were measured during the normal operation period of the institute were found to be many times higher than the respective outdoor PM10 concentrations of the same periods. On the contrary, the indoor PM10 concentrations which were measured during the holiday period were found to be lower than their corresponding outdoor values. Indoor O₃ and CO concentrations were found to be in low level. Indoor PM10 concentrations were found to be in a relative good correlation with O₃ (r = 0.45) and in high correlation (r = 0.98) with CO concentrations. On average, total elements concentrations were much higher indoors relative to outdoors. Based on above findings we attempted to determine the pollution sources of the indoor environment and to investigate some parameters or chemical processes that affect indoor pollutants’ levels.     

Estimation of nitrogen flow change in Beijing,China, for the years 1995, 2000, and 2004

Rapid economic growth in China has led to environmental pollution. Recycling nutrients is essential for sustainable agriculture, and it is necessary to estimate the amount of available organic resources in order to achieve this. Using nitrogen as a tracer, we estimated the organic resource flows in 1995, 2000, and 2004 in Beijing. The agricultural nitrogen flow was calculated from the fertilizer, agricultural product, and byproduct flows. The livestock nitrogen flow was calculated from the feed, excretion, and stock flows. The human nitrogen flow was calculated from the food intake, excretion, and food waste flows. The amounts of recyclable organic resources were estimated from these nitrogen flows. The Daxing, Fangshan, Miyun, Shunyi, and Tongzho areas had high nitrogen loads in 2004, as did the outer suburbs, but Beijing proper had an extremely low nitrogen flow and the inner suburbs had low nitrogen flows. The estimated amount of compost that could be produced from domestic organic waste across Beijing was equivalent to 88,100 t of nitrogen. The Beijing area contains 394,100 ha of farmland, so, if the compost was applied at an equivalent of 100 kg of nitrogen per hectare, the equivalent of 48,000 t of nitrogen would be surplus.     

Residential Flood Damage After Hurricane Floyd,Mold, Household Remediation,and Respiratory Health

We conducted a retrospective, cross‐sectional study of flooding, mold exposure, remediation, and respiratory symptom prevalence on a random sample of respondents from Bound Brook, New Jersey, a community that received extensive flood damage from Hurricane Floyd in September 1999. Over 3,000 homes were impacted, some with water damage to the second floor. Many required condemnation. In 2001 to 2002 we conducted a randomized telephone survey of 29 families still living in flood‐damaged and repaired homes and 18 families who had not experienced flood damage from Floyd. Flood status was the last question on the interview, leaving the interviewer effectively blinded as to status. Flood damage was a strong predictor of mold growth (p < 0.001), and there was a strong association between flooding and physician‐confirmed respiratory symptoms in the aftermath of the flood (28 of 29 cases vs. 10 of 18 referents; p < 0.001). There was also an association between flood status and continued symptom prevalence in the month prior to the interviews (22 of 29 cases vs. 6 of 18 referents; p < 0.01). Most flooded homes required removal and replacement of various building materials, which was usually delayed for days or weeks pending re‐occupancy. Many occupants participated in the renovation without adequate personal protection. Persons assisting with cleanup work were more likely to report five or more symptoms (p < 0.002). Smokers with mold damage reported five or more symptoms in the 30 days before the interviews, more frequently than nonsmokers with mold damage. These results are consistent with previous reports of flooding, mold, and illness, but demonstrate that self‐remediation of mold (particularly with lack of training and personal protective equipment) and smoking are significant risk factors for mold‐related symptoms. Exposure during cleanup of moldy materials was a significant contributor to symptoms, and recommendations should include more reliance on professionals and enhanced personal protective equipment. © 2013 Wiley Periodicals, Inc.     

Effect of chlorine on volatilization of Na, K, Pb, and Zn compounds from municipal solid waste during gasification and melting in a shaft-type furnace

In the present work, a shaft-type furnace model in which the furnace column is divided into multiple cells was proposed and equilibrium reaction calculation software was used to describe the model. The model was used to study the effects of gasification and melting conditions such as temperature, oxygen partial pressure, and chlorine content on the volatilization behaviors of the low-boiling-point metals Na, K, Pb, and Zn during the gasification and melting process of municipal solid waste in a shaft-type furnace. Consequently, the volatilization ratios of Na, K, Pb, and Zn compounds in the exhaust gas from a pilot plant shaft-type furnace were found to be in good agreement with the calculation results, and the Na, K, Pb, and Zn compounds were volatilized mainly as metal chlorides in the temperature range up to approximately 1173 K. With a further rise in temperature, these low-boiling point metals were volatilized as metallic forms. It was found that almost 100% of Pb and Zn compounds were volatilized regardless of the chlorine content in municipal solid waste; in contrast, the volatilization rates of Na and K increased when the chlorine content increased. Finally, Na, K, Pb, and Zn compounds were converted from reduced metals to metal chlorides such as NaCl, KCl, PbCl₂, and ZnCl₂ with an increase in the ratio of chlorine to each metal.     

Tensile Strength, Elongation, Hardness, and Tensile and Flexural Moduli of Injection-Molded TPS Filled with Glycerol-Plasticized DDGS

Continuing growth of biofuel industries is generating large amounts of coproducts such as distillers dried grains with solubles (DDGS) from ethanol production and glycerol from biodiesel. Currently these coproducts are undervalued, but they have application in the plastics industry as property modifiers. This research effort has quantified the effects on mechanical properties of adding DDGS and glycerol to a commercial thermoplastic starch (TPS). The methodology was to physically mix DDGS, as filler, with the TPS pellets and injection mold the blends into test bars using glycerol as a processing aid. The bars were then mechanically tested with blends from 0 to 65 %, by weight, of plasticized filler. The test bars were typically relatively brittle with little yielding prior to fracture with elongation between 1 and 3 %. The addition of glycerol enabled molding of blends with high levels of DDGS but did not increase strength. Any presence of filler decreased the tensile strength of the starch, and up to 30 % filler, the tensile strength drops about 15 %. The 20 and 50 % blends (without glycerol) have slightly greater stiffness than pure starch. With some other blends, the presence of plasticized filler degrades the tensile modulus with 35 % filler yielding about 1/3 the stiffness. Changes in the flexural modulus are much more pronounced as 20–25 % filled TPS has a 30 % increase in flexural stiffness. In terms of surface hardness, blends up to 60 % filler are within 20 % of the TPS baseline.     

Organometals of tin, lead and mercury compounds in landfill gases and leachates from Bavaria, Germany

Organo-Sn, -Pb and -Hg compounds were monitored in gases and leachates of 11 municipal waste landfills and one hazardous waste landfill from Bavaria, Germany, with the objectives to estimate the methylation of Sn, Pb and Hg and to assess the risk of their release into the adjacent environment. In the gases, tetramethyl Sn predominated (>80% of total gaseous Sn) with concentrations up to 160mug Sn m(-3). Dimethyl-Hg and tetramethyl-Pb were only occasionally detected with concentrations up to 2.9 and 2.1mugm(-3) as Hg or Pb, respectively. In all leachates, trimethyl-Sn dominated with a maximum concentration of 2100ng Sn L(-1). No organo-Pb compounds were found, and monomethyl-Hg was detected in only one leachate. The concentrations of trimethyl-Sn were up to 100-fold higher in the condensate water than in leachates, and the concentrations of organo-Sn compounds were lower in the adjacent groundwater than in the corresponding leachates. The high abundance of methylated Sn species in the gases and leachates indicates Sn methylation, suggesting the landfill as a source for organo-Sn compounds. In comparison, methylation of Hg and Pb was of little importance, probably due to low Hg concentrations and low rates of Pb methylation in the landfill. The risks of organo-Sn compounds release to the adjacent air is low due to flaring of landfill gases. However, there is probable release of organo-Sn compounds, especially trimethyl-Sn, to the adjacent groundwater.