Photo-Fenton Oxidative System for Removing Tartrazine Yellow Dye in Aqueous Medium Using Y-fe Zeolite As Catalyst

The synthesis and application of heterogeneous solid catalysts in Fenton-type processes have been shown to be a promising alternative for the removal of hazardous pollutants. In this context, the aim of this study was to prepare and characterize a heterogeneous solid iron catalyst supported on zeolite Y for the degradation of yellow food coloring tartrazine (TY). The catalyst was produced through humid ion exchange and characterized by the physisorption of N2, XRD, SEM, TEM and EDX. The efficiency of the catalyst was evaluated through the degradation of tartrazine yellow dye in a batch regime, and the influence of some of the main operational parameters was also evaluated. The characterizations confirmed the presence of iron on the surface of zeolite Y and the increase in the specific area and pore volume after ion exchange. The catalyst used in the photo-Fenton system was extremely efficient, with a removal of approximately 98% in 120 min in the experimental conditions: [TY]0 = 10 mg/L, [H2O2]0 =200 g/L, Y-Fe dosage=1.5 g/L and pH= 3.0. It was possible to recover the catalyst and use it in five reuse cycles, showing its stability and potential application of this catalyst in heterogeneous photo-Fenton systems.

TBO Degradation by Heterogeneous Fenton-like Reaction Using Fe Supported over Activated Carbon

This study reports on the synthesis, immobilization, and stabilization of iron (Fe) particles in activated carbon (AC) from date stem material for the heterogeneous Fenton-like removal of hazardous pollutants from water. AC-Fe was synthesized through a simple and sustainable chemical reaction using and resulting in an environmentally friendly material (AC-Fe). X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray analyses (EDX) were used to characterize the synthesized samples. XRD, FTIR and XPS results showed the successful incorporation of iron particles onto AC. SEM images indicated smooth surfaces with clearly visible Fe particles. Compared to pure AC, AC-Fe showed higher degradation rates of toluidine blue O (TBO) dye. The effects of the initial pH and TBO and H2O2 concentrations on TBO degradation were investigated. The AC-Fe catalyst proved highly efficient in the Fenton-like degradation of TBO (50 ppm), with the removal of up to 99% in 3 min. This catalyst was used efficiently for up to four repeated cycles. The improved catalytic activity of AC-Fe was related to Fe particles for the generation of HO•. These results prove that date stems—a waste product from agriculture—are a suitable precursor for preparing an appropriate AC and catalyst and for eliminating dyes from an aqueous solution by a heterogeneous Fenton-like reaction. The above results open an interesting avenue for the development of functional green catalysts based on AC-Fe for pollution removal.

Gas hazard of explosives used in the mining industry

Reducing emissions of hazardous pollutants that have a negative impact on the environment and human health has been approved as one of the strategic objectives of Russia's development. More than 90% of minerals in mined using blast energy. Despite an increase in the share of non-explosive component mixtures used in mining, blasting still poses a hazard to miners as the gaseous detonation products are potentially dangerous. The composition of blast gaseous products is extremely important in underground blasting because air exchange is difficult under these conditions and the blast products can contaminate the atmosphere of underground excavations, causing illness or poisoning of miners. Currently, there are no uniform requirements for obtaining information on the amount of gaseous blast products that would be hazardous to the human organism. Available documents do not contain information on the permissible amounts of toxic oxides per 1 kg of explosive detonated. The article compares the results of studying gas toxic hazard of industrial explosives obtained by different methods and based on different criteria.