Distinctive adsorption and desorption behaviors of temporal and post-treatment heavy metals by iron nanoparticles in the presence of microplastics

Microplastics enhance the adsorption capacity of zinc oxide nanoparticles: Interactive mechanisms and influence factors

Microplastics (MPs) are of particular concern due to their ubiquitous occurrence and propensity to interact and concentrate various waterborne contaminants from aqueous surroundings. Studies on the interaction and joint toxicity of MPs on engineered nanoparticles (ENPs) are exhaustive, but limited research on the effect of MPs on the properties of ENPs in multi-solute systems. Here, the effect of MPs on adsorption ability of ENPs to antibiotics was investigated for the first time. The results demonstrated that MPs enhanced the adsorption affinity of ENPs to antibiotics and MPs before and after aging showed different effects on ENPs. Aged polyamide prevented aggregation of ZnONPs by introducing negative charges, whereas virgin polyamide affected ZnONPs with the help of electrostatic attraction. FT-IR and XPS analyses were used to probe the physicochemical interactions between ENPs and MPs. The results showed no chemical interaction and electrostatic interaction was the dominant force between them. Furthermore, the adsorption rate of antibiotics positively correlated with pH and humic acid but exhibited a negative correlation with ionic strength. Our study highlights that ENPs are highly capable of accumulating and transporting antibiotics in the presence of MPs, which could result in a widespread distribution of antibiotics and an expansion of their environmental risks and toxic effects on biota. It also improves our understanding of the mutual interaction of various co-existing contaminants in aqueous environments.

Interaction of microplastics with heavy metals in soil: Mechanisms, influencing factors and biological effects

Microplastics (MPs) and heavy metals (HMs) in soil contamination are considered an emerging global problem that poses environmental and health risks. However, their interaction and potential biological effects remain unclear. Here, we reviewed the interaction of MPs with HMs in soil, including its mechanisms, influencing factors and biological effects. Specifically, the interactions between HMs and MPs mainly involve sorption and desorption. The type, aging, concentration, size of MPs, and the physicochemical properties of HMs and soil have significant impacts on the interaction. In particular, MP aging affects specific surface areas and functional groups. Due to the small size and resistance to decomposition characteristics of MPs, they are easily transported through the food chain and exhibit combined biological effects with HMs on soil organisms, thus accumulating in the human body. To comprehensively understand the effect of MPs and HMs in soil, we propose combining traditional experiments with emerging technologies and encouraging more coordinated efforts.

Are algae a promising ecofriendly approach to micro/nanoplastic remediation?

How to reduce microplastic pollution in aquatic ecosystem has become the focus of the global attention. The re-removal of microplastics of wastewater treatment plant (WWTP) effluent is gradually being put on the agenda. Recently, algae have been used as an ecofriendly remediation strategy for microplastic removal. Microplastics in sewage can be removed by algae through interception, capture, and entanglement, and can also form heterogeneous aggregates with algae, thereby reducing their free suspensions. Algae can recover nitrogen and carbon from wastewater and can be made into biochar, biofertilizers, and biofuels. However, problematically, this technology has been in the laboratory research stage, and existing research results cannot provide effective basis for its application. Microplastic removal via algae is influenced by wastewater flow rate, microplastic types, and pollutants. Microplastics are only physically fixed by algae, and ensuring that microplastics do not re-enter the environment during resource and capacity recovery is also a key factor limiting the implementation of this technology. The topic of this paper is to discuss the performance of the current tertiary wastewater treatment process - algae process to remove microplastics. Algae can remove nitrogen and phosphorus pollutants in sewage and remove microplastics at the same time, which can realize energy recovery and reduce ecological risks of the effluent. Although algae combined tertiary sewage treatment is a green technology for microplastic removal, its application still needs to be explored. The key challenges that need to be addressed, from single laboratory conditions to complex conditions, from small-scale testing to large-scale simulations, lie ahead of the application of this friendly technology.