Study of the phytoremediation potential of native plant species identified in an area contaminated by volatile organic compounds: a systematic review.

Phytoremediation is a process that uses plants in situ to promote remediation of environments contaminated by organic or inorganic compounds. Phytoremediating species develop methods such as phytoextraction, rhizofiltration, phytodegradation, and phytovolatilization, which can manifest themselves individually or together in a single plant. This study aims to evaluate, through a systematic review, the potential phytoremediation techniques of the genera Syagrus (Mart.), Nephrolepis, Cyperus (L.), Mimosa (L.), Schinus (L.), Brachiaria, and Eryngium (L.) found in a humid area of Rio Grande do Sul, Brazil. The genera that presented significant numbers in the databases consulted were Cyperus and Brachiaria, followed by Nephrolepis. The first two are considered the most promising for phytoremediation processes. The other genera mentioned obtained favorable results for organic contaminants. The studies around these genera are still recent. It is necessary, in research, to highlight which phytoremediation processes the plants exert in relation to the contaminant of the place. In addition, priority should be given to native species that can establish themselves in the environment and that would not unbalance and harm the surrounding biota and ecosystem.

The research presents a survey of two decades in four multidisciplinary and international databases, identifying the limitation of research related to volatile and semi-volatile organic compounds, as well as contributing to the identification of native plant species that perform phytoremediation mechanisms.

Review of the rice production cycle: by-products and the main applications focusing on rice husk combustion and ash recycling.

One of the consequences of industrial food production activities is the generation of high volumes of waste, whose disposal can be problematic, since it occupies large spaces, and when poorly managed can pose environmental and health risks for the population. The rice industry is an important activity and generates large quantities of waste. The main solid wastes generated in the rice production cycle include straw, husk, ash, bran and broken rice. As such, the aim of this article is to present a review of this cycle, the waste generated and the identification of opportunities to use them. Owing to impacts that can be minimised with the application of rice husk ash as a by-product, this work is focused on the recycling of the main wastes. In order to achieve that, we performed theoretical research about the rice production cycle and its wastes. The findings point to the existence of an environmentally suitable use for all wastes from the rice production cycle. As rice, bran and broken rice have their main use in the food industry, the other wastes are highly studied in order to find solutions instead of landfilling. Straw can be used for burning or animal feeding. The husk can be used for poultry farming, composting or burning. In the case of burning, it has been used as biomass to power reactors to generate thermal or electrical energy. This process generates rice husk ash, which shows potential to be used as a by-product in many different applications, but not yet consolidated.