Heavy metals are toxic and non-biodegradable environmental contaminants that seriously threaten human health. The remediation of heavy metal-contaminated water and soil is an urgent issue from both environmental and biological points of view. Recently, nanomaterials with excellent adsorption capacities, great chemical reactivity, active atomicity, and environmentally friendly performance have attracted widespread interest as potential adsorbents for heavy metal removal. This review first introduces the application of nanomaterials for removing heavy metal ions from the environment. Then, the environmental factors affecting the adsorption of nanomaterials, their toxicity, and environmental risks are discussed. Finally, the challenges and opportunities of applying nanomaterials in environmental remediation are discussed, which can provide perspectives for future in-depth studies and applications.

Non-invasive Micro-test Technology (NMT) is a selective microelectrode technique which can detect the flux rates and three-dimensional motion directions of ions or molecules into and out of living organisms in situ without damaging the sample. It has the advantages of maintaining sample integrity, high temporal and spatial resolution, and being able to measure multiple sites simultaneously. In this paper we provide a comprehensive review on the development of NMT in recent years. Its principles, characteristics, and the differences with other microelectrode techniques are introduced. We discuss the applications of NMT in the field of phytoremediation, plant resistance, water quality monitoring, and toxicity mechanisms of heavy metals on organisms. Furthermore, the challenges and future prospects of NMT in the environmental field are presented.