Plasma Technology for Phosphogypsum Treatment

The phosphate industry generates a large amount of waste called phosphogypsum (PG). Generally, this waste is discharged without any treatment, and it causes considerable environmental problems. Hence, the objective of this study is the treatment of phosphate waste using thermal plasma technology. First, the waste is characterized using different techniques, such as X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and inductively coupled plasma (ICP). Such characterization shows that the waste contains different toxic elements, such as heavy metals, fluorine, chlorine, sulfur, and phosphorus. For this reason, a plasma reactor is used to separate toxic elements from metals, such as silicon, aluminum, and magnesium, with a pyrolysis/combustion plasma system. In this work, the influence of different parameters, such as time of treatment and plasma current, on the volatility of toxic elements is studied. The obtained results show that after 40 min of treatment and at a plasma current of 160 A, the phosphogypsum completely melts, and the most toxic elements, namely Pb, Cd, V, Cr, and As, are completely vaporized.

Post Harvest Applications of Cold Plasma Technology: A Review

Plasma is the fourth state of matters which have a wide application in food processing and post harvest technology. Plasma when applied over crops has tremendous effects in improvement in the quality and other post harvest attributes. Application of cold plasma technology could effectively induce desirable changes in its overall quality and diverse physiology. The following review would discuss the application of non-thermal plasma technology to disinfect and decontaminate processed food product and fresh horticultural crops. Horticultural crops which are treated with plasma technology do not show any loss in nutrients. The packaging materials can also be sterilized by using plasma technology. Similarly, the food packed inside a package can also be sterilized without harming the package integrity. Beside that it can also be used to reduce the enzymatic activity of fresh fruits and vegetables and help to modify the food properties. Cold plasma technology can penetrate fungal biofilm and destroy resting fungal spores. This technology can also be harnessed to remove residual toxic pesticide from food products and fresh fruits and vegetables. However, the technology might sound a bit expensive but have a long future in terms of utility.

Non-Thermal Plasma-Assisted Catalytic Reactions for Environmental Protection

“Non-thermal plasma technology” (NTP) has notably increased [...]

Non-Thermal Plasma Coupled with Catalyst for the Degradation of Water Pollutants: A Review

Non-thermal plasma is one of the most promising technologies used for the degradation of hazardous pollutants in wastewater. Recent studies evidenced that various operating parameters influence the yield of the Non-Thermal Plasma (NTP)-based processes. In particular, the presence of a catalyst, suitably placed in the NTP reactor, induces a significant increase in process performance with respect to NTP alone. For this purpose, several researchers have studied the ability of NTP coupled to catalysts for the removal of different kind of pollutants in aqueous solution. It is clear that it is still complicated to define an optimal condition that can be suitable for all types of contaminants as well as for the various types of catalysts used in this context. However, it was highlighted that the operational parameters play a fundamental role. However, it is often difficult to understand the effect that plasma can induce on the catalyst and on the production of the oxidizing species most responsible for the degradation of contaminants. For this reason, the aim of this review is to summarize catalytic formulations coupled with non-thermal plasma technology for water pollutants removal. In particular, the reactor configuration to be adopted when NTP was coupled with a catalyst was presented, as well as the position of the catalyst in the reactor and the role of the main oxidizing species. Furthermore, in this review, a comparison in terms of degradation and mineralization efficiency was made for the different cases studied.