Congo red dye degradation using Fe-containing mineral as a reactive material derived from waste foundry dust.

This study investigated the applicability of industrial waste. The high affinity of Fe-based products is widely used for industrial effluents because of their capability to oxidize contaminants. Waste foundry dust (WFD) is an Fe oxide that has been investigated as a potential reactive material that causes the generation of reactive oxidants. We aimed to investigate the physicochemical properties of WFD and the feasibility in the Fenton oxidation process. The WFD was used as a catalyst for removing Congo red (CR), to evaluate the generation of •OH and dissolution of Fe during the oxidation process. The linkage of •OH generation by WFD with eluted Fe(II) through the Fe dissolution was found. The Fenton oxidation reaction, CR degradation was affected by H2O2 concentration, initial pH, WFD dosage, initial CR concentration, and coexisting anions. The CR degradation efficiency increased with an increase in H2O2 concentration and WFD dosage. In addition, chloride and sulfate in solution promoted CR degradation, whereas carbonate had a negative effect on the Fenton oxidation process. The elution of Fe promotes CR degradation, over three reuse cycles, the degradation performance of the CR decreased from 100 to 81.1%. For the Fenton oxidation process, •OH generation is linked to Fe redox cycling, the surface passivation and Fe complexes interrupted the release of reactive oxidants, which resulted in the degradation of the CR decreased. This study proposed that WFD can serve as catalysts for the removal of CR.

A new approach for quantifying ecological sustainability in waste management by using the method of modelling.

Human activity has an ever-increasing impact on the environment. In order to understand all processes and interactions behind this change, one has to analyze the environmental impact. Life Cycle Assessments (LCAs) are one way to achieve this, which, however, are time-consuming and often associated with high costs, as well as the requirement of specialized knowledge and software. This paper introduces a model, which allows an initial assessment. The model enables a more pragmatic way and may be considered as a first step in order to implement ecological sustainability considerations into companies. Based on a real-world problem, namely the disposal of foundry dust, the model is explained in a vivid manner.

Removal of Methyl Red from Aqueous Solution Using Polyethyleneimine Crosslinked Alginate Beads with Waste Foundry Dust as a Magnetic Material.

In this study, a cost-effective adsorbent based on sodium alginate (SA) with waste foundry dust (WFD) was fabricated for the removal of methyl red (MR) from aqueous media. However, the utilization of WFD/SA beads to remove anionic dyes (such as MR) from effluents has limitations associated with their functional groups. To improve the adsorption performance, WFD/SA-polyethyleneimine (PEI) beads were formed via PEI crosslinking onto WFD/SA beads, which could be attributed to the formation of amide bonds from the carboxyl and amino groups due to the change of N-H bonds in the reaction. The Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) results indicated that PEI was crosslinked on the WFD/SA via a chemical reaction. In the FTIR spectra of WFD/SA-PEI, peaks of the -COO (asymmetric) stretching vibration shifted to 1598 and 1395 cm-1, which could be attributed to the hydrogen-bonding effect of the N-H groups in PEI. In the N1s spectrum, three deconvoluted peaks were assigned to N in -N= (398.2 eV), -NH/-NH2 (399.6 eV), and NO2 (405.2 eV). WFD/SA-PEI beads were assessed and optimized for aqueous MR adsorption. The WFD/SA-PEI beads showed a high removal efficiency for MR (89.1%) at an initial concentration of 1000 mg/L, and presented a maximum MR adsorption capacity of 672.7 mg/g MR. The adsorption process showed a good fit with the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model. The amino and hydroxyl groups in the WFD/SA-PEI beads facilitate strong hydrogen bonding and electrostatic interactions. Moreover, these WFD/SA-PEI beads were easily recovered after the adsorption process.

Waste foundry dust (WFD) as a reactive material for removing As(III) and Cr(VI) from aqueous solutions.

This study evaluates the use of waste foundry dust (WFD) as a reactive material for mitigating water pollution using As(III) and Cr(VI) as model contaminants. A detailed structural characterization of WFD was performed using X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Batch removal experiments and kinetic studies for removal of both As(III) and Cr(VI) were conducted at various initial pH values (2-10), concentrations (1-100 mg/L), and solid-to-liquid ratios (2.5-125 g/L). The results show that WFD consisted of small particles (< 30 µm) with magnetic properties, mainly composed of quartz (SiO2) and magnetite (Fe3O4). The maximum removal capacity of WFD was 12.6 mg/g for As(III) at pH 3.0 and 6.1 mg/g for Cr(VI) at pH 5.0. WFD was effective in a wide pH range, from 3.0 to 8.0, and in high concentrations, up to 100 mg/L. WFD removed As(III) and Cr(VI) from aqueous solutions through complex processes including adsorption, precipitation, and redox reactions by oxidation of Fe(II). The results of this study suggest that WFD can be used as a reactive material for removal of As(III) and Cr(VI) from aqueous solutions.

Data describing characteristics of waste foundry dust (WFD), sorbent obtained before and after batch sorption tests using As(III) and Cr(VI) aqueous solutions.

This article presents data on characteristics of waste foundry dust (WFD), sorbent obtained before and after batch sorption tests using As(III) and Cr(VI) aqueous solutions, by performing X-ray Diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses. Data are related to a research article "Waste foundry dust (WFD) as a reactive material for removing As(III) and Cr(VI) from aqueous solutions" [1]. The data provide information obtained from various analytical methods to investigate mechanisms of As(III) and Cr(VI) removal from aqueous solutions by WFD, an industrial by-product. These data can be of interest to researchers studying contaminant removal mechanisms by reactive materials, in particular industrial by-products.

Comprehensive utilization of foundry dust: Coal powder and clay minerals separation by ultrasonic-assisted flotation.

Clay sand casting generates a large amount of foundry dust (FD), and the presence of coal powder in the FD makes it difficult to recycle and utilize. The landfill of the FD creates a serious environmental pollution and wastes a valuable resource. To improve the above situation, the FD was analyzed and characterized by X-ray fluorescence spectrometer (XRF), X-ray diffraction (XRD) and electron probe microanalyzer (EPMA). An ultrasonic-assisted flotation process was developed for the comprehensive utilization of the FD, and the effects of ultrasonic time on the flotation performance and flotation kinetics were investigated. In addition, the two-stage flotation of the FD was conducted. Obtained results showed that the FD mainly consisted of coal powder and clay minerals, and the coal powder was covered by clay minerals. The separation efficiency of the coal powder and clay minerals can be significantly enhanced by ultrasonic pretreatment, and the optimal ultrasonic time was 30 min. The flotation kinetics analysis results indicated that the first-order model with rectangular distribution was more reasonable for the data fitting of the ultrasonic-assisted flotation. Furthermore, the concentrate and tailings obtained by the two-stage flotation had achieved an acceptable result, favoring the comprehensive utilization of the FD.

Influence of Superhydrophobic Coating on the Water Resistance of Foundry Dust/Magnesium Oxychloride Cement Composite.

In this work, magnesium oxychloride cement (MOC) was used to realize the resource use of foundry dust (FD). Portland cement (PC)-based superhydrophobic coating was prepared on the surface of FD/MOC composite to improve the water resistance of the composite. First, the FD/MOC composites with different contents of FD were prepared. The phase structure of the composite was analyzed using X-ray diffraction (XRD). The microstructure of the cross-section and surface of the composite was observed using field emission scanning electron microscope (FE-SEM). The mechanical properties of the FD/MOC composites with different FD contents at different ages were tested and analyzed. Secondly, the superhydrophobic coating was prepared on the surface of MOC composite using silane/siloxane aqueous emulsion as the hydrophobic modifier, PC as the matrix and water as the solvent. The microstructure and chemical composition of the PC-based superhydrophobic coating were tested and analyzed. The results show that FD can significantly improve the early strength of the FD/MOC composite. The 28-day compressive strength of the FD/MOC composite decreases with increasing FD content. When the FD content is 30%, the 28-day compressive strength of the FD/MOC composite is as high as 75.68 MPa. Superhydrophobic coating can effectively improve the water resistance of the FD/MOC composite. The softening coefficient of the FD/MOC composite without superhydrophobic coating is less than 0.26, while that of the composite modified by superhydrophobic coating is greater than 0.81.

Mechanical Properties of Natural Rubber Filled with Foundry Waste Derived Fillers.

The main aim of this study is to evaluate the possibility of applying foundry dust (FD) derived filler for the preparation of natural rubber (NR) based composites by characterizing the mechanical properties. The as-received FD was processed via a simple and low-cost procedure, including sieving, deironing and milling using a variety of industrial equipment. FD powders before and after silane coupling agent (Si 69) modification were used as fillers for NR. NR composites inserted with different content of modified and unmodified FD up to 50 phr were prepared via dry-mixing method. Then, comprehensive mechanical performances were performed on the corresponding vulcanizates. It was demonstrated that NR composite filled with 50 phr of modified FD exhibited optimized comprehensive mechanical performance. Tear strength and hardness is increased by 21.3% and 12.8% than pure NR, respectively. Tensile strength is reduced by 21% and elongation at break remained nearly unchanged. Additionally, the composite showed a large increment of 50.9% for its wet grip property, while exhibited an increment of only 11.9% for its rolling resistance in comparison with the composite containing 10 phr of FD. The findings of this study may provide a new application area for the large amounts of utilization of foundry waste with a high level of value being added.

Health status of male steel workers at an electric arc furnace (EAF) in Trentino, Italy.

BACKGROUND: The aim of this retrospective cohort study was to determine if the workers of an Electric Arc Furnace (EAF), which recycles scrap, had higher mortality and morbidity due to possible exposure to pollutants at work. EAFs do not run on coke ovens. In EAFs 40 % of the particulate matter (PM) is made up of PM 2.5. The foundry dust contained iron, aluminum, zinc, manganese, lead, chromium, nickel, cadmium, mercury, arsenic, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls and dioxins. METHODS: Mortality study: a cohort of 331 exposed workers (6731 person-years) was studied from 19/03/1979 to 31/12/2009 (mean follow up 20.7 years). The group of exposed workers was compared to the general population and to a small control group of 32 workers from the same company. Morbidity study: rates of exemption from health fee for the seven major diseases of 235 exposed workers were compared to the rates of exemption in the Province of Trento. RESULTS: Mortality study: an excess mortality was found in the exposed workers as compared to the general population (SMR 1.13; 95 % CI: 0.76-1.62; 29 deaths) and to the internal group (RR 2.34; 95 % CI: 0.39-95.7). The mortality rate was increased for all tumours (SMR 1.36; 95 % CI: 0.75-2.29; 14 cases), for lung cancer (SMR 3.35; 95 % CI 1.45-6.60; 8 cases), for ischemic heart disease (SMR 1.27; 95 % CI: 0.35-3.26; 4 cases), for chronic liver disease (SMR 1.16; 95 % CI: 0.14-4.20; 2 cases) and for injury and poisoning (SMR 1.32; 95 % CI: 0.48-2.88; 6 cases). Morbidity study: there was a statistically significant increase of diabetes, rheumatoid arthritis, hypertension and cardiovascular diseases in exposed workers. CONCLUSIONS: With the limitations of this relatively small cohort, we found a statistically significant increase of diabetes, cardiovascular diseases and deaths due to lung cancer in exposed workers. These findings cannot be explained by PAH exposure alone; metal particulates are the most important pollutants in the working area of EAFs. A reliable method for measuring metal PM in tissues is urgently needed for exposure assessment. This study underlines the necessity to maximize the standards of security toward foundry dusts/diffuse emission. Further studies on EAF's are needed to confirm our findings and to increase statistical power.