Contaminants, organic or inorganic, represent a threat for the environment and human health and in recent years their presence and persistence has increased rapidly. For this reason, several technologies including bioremediation in combination with nanotechnology have been explored to identify more systemic approaches for their removal from environmental matrices. Understanding the interaction between the contaminant, the microorganism, and the nanomaterials (NMs) is of crucial importance since positive and negative effects may be produced. For example, some nanomaterials are stimulants for microorganisms, while others are toxic. Thus, proper selection is of paramount importance. The main objective of this review was to analyze the principles of bioremediation assisted by nanomaterials, nanoparticles (NPs) included, and their interaction with environmental matrices. It also analyzed the response of living organisms employed to remediate the contaminants in the presence of nanomaterials. Besides, we discuss the international regulatory frame applicable to these technologies and how they might contribute to sustainability.

Phytoremediation is an attractive strategy for cleaning soils polluted with a wide spectrum of organic and inorganic toxic compounds. Among these pollutants, heavy metals have attracted global attention due to their negative effects on human health and terrestrial ecosystems. As a result of this, numerous studies have been carried out to elucidate the mechanisms involved in removal processes. These studies have employed many plant species that might be used for phytoremediation and the obtention of end bioproducts such as biofuels and biogas useful in combustion and heating. Phytotechnologies represent an attractive segment that is increasingly gaining attention worldwide due to their versatility, economic profitability, and environmental co-benefits such as erosion control and soil quality and functionality improvement. In this review, the process of valorizing biomass from phytoremediation is described; in addition, relevant experiments where polluted biomass is used as feedstock or bioenergy is produced via thermo- and biochemical conversion are analyzed. Besides, pretreatments of biomass to increase yields and treatments to control the transfer of metals to the environment are also mentioned. Finally, aspects related to the feasibility, benefits, risks, and gaps of converting toxic-metal-polluted biomass are discussed.

Since engineering nanoparticles (ENP) have been developed for using in industry and human commodities, is common to find their wastes and by-products from industrial chemical reactions, and it is also possible to find incidental nanoparticles in the environment. Currently, the remediation of polluted soils using nanotechnologies has become an emerging area with a huge potential to improve the performance of traditional remediation technologies. However, environmental concerns have also emerged regarding human and environmental health when nanotechnologies are released to ecosystems. The goal of this manuscript is to highlight the environmental benefits and risks that arise when nanotechnologies are used to remediate polluted soils. We searched Web of Science and Scopus in order to get latest updated information and patents pertaining to developments in the field of nanotechnologies for decontaminating soils. It has been determined that soil nanoremediation has some advantages, but it also has some disadvantages related to the final disposal of nanoparticles, nanomaterials, or nanodevices. Will some nanotechnologies be our pitfall? Nanoparticle toxicity has to be assessed and the standardization of techniques should be set by scientists and decision-makers worldwide. Cutting-edge knowledge regarding the use of nanoparticles to decontaminate soils has to move forward, but environmental quality, human health, and social welfare should also be ensured.