Number Of Hazardous Compounds Research Articles

Evaluation of the Immobilization of Fly Ash from the Incineration of Municipal Waste in Cement Mortar Incorporating Nanomaterials—A Case Study

Fly ash generated in the process of combustion of municipal waste is classified as hazardous waste. Its management today has become a significant problem. One of the methods of safe management of such ash may be using it for the production of concrete as a partial replacement for cement. Using immobilization, the number of hazardous compounds could be limited so that the obtained new material would be safe for the natural environment. Recovery of byproducts—in this case, fly ash—complies with the business models applied in the production cycle in the circular economy model. Such a solution may result in saving energy, limiting CO2 emissions, reducing the use of natural resources, and management of dangerous waste. It should be added that concretes with the addition of hazardous waste would be used for industrial purposes according to the binding legal regulations. This article presents the influence of the addition of fly ash on the selected mechanical properties of concrete. Fly ash from the incineration of municipal waste was used as a partial replacement of CEM I concrete at amounts of 4%, 8%, and 18% of its mass. The compressive strength and flexural strength of such concretes were tested after 28 days of concrete curing. This article also presents the tests of the leachability of contaminants from fly ash and concretes produced with Portland cement CEM I. The test results confirm that immobilization is an effective process that limits the amount of contamination in the water extract. Zinc, lead, and chrome were almost completely immobilized by the C-S-H (calcium silicate hydrate) concrete phase, with their immobilization degree exceeding 99%. Chloride content also underwent immobilization at a similar level of 99%. The sulfates were immobilized at the level of 96%. The subject matter discussed in this article is essential because, to protect the natural environment and, thus, reduce the use of natural resources, it is increasingly necessary to reuse raw materials—not natural, but recycled from the industry. Waste often contains hazardous compounds. A proposal for their safe disposal is their immobilization in a cement matrix. An important aspect is reducing leachability from concrete as much as possible, e.g., using nanomaterials. The effectiveness of reducing the leachability of hazardous compounds with the proposed method was checked in this study.

Laser vs. thermal treatments of green pigment PG36: coincidence and toxicity of processes

Comparative laser and thermal treatments were carried out on PG36, a green phthalocyanine-based pigment, permitted in European countries where legislation on tattoo composition was issued. Prior to the treatments, PG36 was characterized by SEM imaging, EDX, IR and UV–Vis spectroscopies, revealing an excess of Si and C and O as compared to the pure halogenated Cu-phthalocyanine. Laser treatments were carried out with a Nd:YAG device applied to H2O and propan-2-ol dispersions. Pyrolysis and calcinations were carried out in air or under N2 flow. The outcome of the different procedures was analyzed by UV–Vis spectroscopy, GC–mass spectrometry, X-ray diffraction of the solid residues, SEM microscopy and dynamic light scattering. The comparative analysis indicated the production of different fragment compounds depending on the treatment, (pyrolysis or laser), and, to some extent, to the solvent of the dispersion, with pyrolysis generating a larger number of hazardous compounds. Hydrocarbons and cyclic siloxanes present as additives in PG36 were stable or degraded depending on the treatment. The morphology of the products is also treatment-dependent with nanoparticles < 20 nm and fibers being produced upon laser treatments only. Based on the experimental findings, the equivalence of laser and thermal treatments is evaluated.

Human exposure to trace elements and PCDD/Fs around a hazardous waste landfill in Catalonia (Spain)

Hazardous waste landfills (HWLs) usually mean the end of non-reusable, non-recyclable and non-recoverable wastes derived from industrial activities. A number of hazardous compounds and toxic elements, such as PCDD/Fs, Cd, Cr, Hg, Pb and As, is associated to these wastes. The HWL of Castellolí (Catalonia, Spain) treats a variety of hazardous wastes, which include bottom ashes from waste incinerators and asbestos potentially containing those toxicants. In 2007, our group began a surveillance program inside the HWL and in nearby villages focused on assessing the environmental levels of PCDD/Fs and toxic elements. Here we summarize the most updated results, corresponding to data from samples collected between 2015 and 2018. The levels of most trace elements (As, Cd, Cr, Ni and Pb) in soils, as well as those of Cd and Pb in air, were significantly higher (p < 0.01) inside the HWL than outside. However, no relevant differences were noted in the concentrations of trace elements when comparing the results of villages near the HWL with those located farther. With respect to PCDD/Fs, a progressive decrease was observed between the first (2007) and most recent (2018) surveys. The human health risks associated with the exposure to trace elements and PCDD/Fs exposure were within acceptable ranges according to national and international legislations (HQ < 1 and Cancer risk < 10−5).

A Safe and Effective Propylene Glycol Based Capture Liquid for Fruit Fly (Diptera: Tephritidae) Traps Baited with Synthetic Lures

Abstract Antifreeze is often used as the capture liquid in insect traps for its preservative and evaporative attributes. In tests reported herein, fruit fly traps using non-toxic recreational vehicle (RV) propylene glycol based antifreeze captured significantly more Anastrepha ludens (Loew) than did traps with the automotive antifreeze. Automotive antifreeze has a characteristic odor due to the additive tolytriazole. The odor may have been mildly repellent. Whether better or equal in efficacy, fruit fly trapping programs should consider using the non-toxic formulation as an environmentally friendly alternative over the automotive antifreeze, which contains a number of hazardous compounds.

Microwave Treatment of Emissions From Waste Materials

AbstractA microwave off-gas system has been designed and fabricated to destroy or decompose emissions that arise from microwave treatment of printed circuit boards (PCBs). Preliminary gas chromatography data on emissions that resulted from combustion of PCBs showed significant decreases in the concentration and number of hazardous compounds detected in the off-gases after treatment. Investigations have continued in this area to demonstrate the reproducibility of the initial results and to determine critical control parameters for optimization of the system. The results of these studies are presented.

On the Occurrence of Transient Puffs in a Rotary Kiln Incinerator Simulator I. Prototype Solid Plastic Wastes

In the operation of practical rotary kiln incinerators, the hazardous waste charge is often introduced in drums or containers in a batch mode. The ensuing transient condition, caused by the rapid devolatilization of waste materials, can momentarily deplete or displace local levels of excess oxygen in the kiln, resulting in heavy transient loadings of unburned gaseous and particulate hydrocarbons (here denoted as "puffs") leaving the kUn. This system upset must then be handled by an afterburner and subsequent air pollution control devices downstream. Such an overcharging or transient condition may even result in unacceptably low destruction of principal organic hazardous constituents (POHC) and the formation of products of incomplete combustion (PIC). A 73-kW (250,000-Btu/h) rotary kiln simulator was designed and constructed to provide engineering insight into the chemical and physical parameters associated with failure mode conditions. To this end, a statistically designed parametric investigation was undertaken to determine which waste and kiln variables (charge mass, charge surface area, charge composition, and kiln temperature) significantly affect both instantaneous intensity and total magnitude of the pollutant puffs leaving the kiln. Emphasis was on the incineration of simple prototype plastic wastes, ranging from polyethylene to polyvinyl chloride. Results demonstrate the relative ease with which failure conditions are experienced, even at high excess air values and high ktin temperatures. Transient puffs leaving the kiln contain a number of hazardous compounds. Increasing kiln temperature does not necessarily decrease the puff intensity and may in fact cause an increase. However, the total mass emitted decreases with increasing temperature. In addition, the mass, surface area, and composition of the charge are all important.

Outer-membrane permeability of bacteria.

Gram-negative bacteria evolved to survive under the conditions in which a number of hazardous compounds are abundant. The outer membrane which protects the cell interior acts as a barrier against such hazardous agents, yet the cells must incorporate the chemicals that are essential for the cellular activity. The devices that Gram-negative bacteria developed to incorporate such essence are the transmembrane pores. These pores could be subdivided into three categories: (1) pore made of porins has a weak solute selectivity; (2) pore made of lamB protein and tsx proteins hold intermediate solute specificity. and (3) pores for the diffusion of vitamin B12 and ferric ion-chelator complexes have a tight solute specificity. Porins are identified from a number of Gram-negatives and from the outer membrane of mitochondria of various sources. Studies on the diffusion properties of these outer-membrane proteins provided essential information to understand membrane transports.