Developments in nanotechnology are leading to a rapid proliferation of new materials that are likely to become a source of engineered nanoparticles (ENPs) to the environment, where their possible ecotoxicological impacts remain unknown. The surface properties of ENPs are of essential importance for their aggregation behavior, and thus for their mobility in aquatic and terrestrial systems and for their interactions with algae, plants and, fungi. Interactions of ENPs with natural organic matter have to be considered as well, as those will alter the ENPs aggregation behavior in surface waters or in soils. Cells of plants, algae, and fungi possess cell walls that constitute a primary site for interaction and a barrier for the entrance of ENPs. Mechanisms allowing ENPs to pass through cell walls and membranes are as yet poorly understood. Inside cells, ENPs might directly provoke alterations of membranes and other cell structures and molecules, as well as protective mechanisms. Indirect effects of ENPs depend on their chemical and physical properties and may include physical restraints (clogging effects), solubilization of toxic ENP compounds, or production of reactive oxygen species. Many questions regarding the bioavailability of ENPs, their uptake by algae, plants, and fungi and the toxicity mechanisms remain to be elucidated.

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Environmental behavior and ecotoxicity of engineered nanoparticles to algae, plants, and fungi

Photocatalysis technology, using semiconductor nano-materials to decompose toxic pollutants under solar light irradiation, displays great prospects for environmental protection. This review gives an overview of the applications of BiOX (X = Cl, Br and I) photocatalysts for efficient photocatalytic degradation (PCD) removal of pollutants in water/air, such as volatile organic compounds (VOCs), organic molecule pollutants, polymer pollutants and biological substances. In addition, the hybridization, facet effects and photocatalytic mechanisms of BiOX are highlighted to offer guidelines for designing highly-active BiOX visible-light-driven (VLD) photocatalysts. Furthermore, the research trends and future prospects of BiOX photocatalysts are also briefly summarized. It may lead to feasible green and efficient photocatalytic reaction systems using BiOX as the photocatalyst.

Recent advances in BiOX (X = Cl, Br and I) photocatalysts: synthesis, modification, facet effects and mechanisms

TiO2-based photocatalysis has become a viable technology in various application fields such as (waste)water purification, photovoltaics/artificial photosynthesis, environmentally friendly organic synthesis and remediation of air pollution. Because of the increasing impact of bad air quality worldwide, this review focuses on the use and optimization of TiO2-based photocatalysts for gas phase applications. Over the past years various specific aspects of TiO2 photocatalysis have been reviewed individually. The intent of this review is to offer a broad tutorial on (recent) trends in TiO2 photocatalyst modification for the intensification of photocatalytic air treatment. After briefly introducing the fundamentals of photocatalysis, TiO2 photocatalyst modification is discussed both on a morphological and an electronic level from the perspective of gas phase applications. The main focus is laid on recent developments, but also possible opportunities to the field. This review is intended as a solid introduction for researchers new to the field, as well as a summarizing update for established investigators.

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TiO2 photocatalysis for the degradation of pollutants in gas phase: From morphological design to plasmonic enhancement

A review on heterogeneous photocatalysis for environmental remediation: From semiconductors to modification strategies

Interaction of engineered nanoparticles with various components of the environment and possible strategies for their risk assessment.

This paper investigated solid-phase photocatalytic degradation of polyethylene (PE) plastic with TiO2 in the ambient air under solar and ultraviolet light irradiation. The photodegradation of the composite plastic was compared with that of pure PE through weight loss monitoring, scanning electron microscopic (SEM) analysis, gas chromatography (GC), FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS). PE-TiO2 composite plastic can be efficiently decomposed and the main products are CO2 and water. The weight-loss of PE-TiO2 (1 wt%) film reached 42% under solar irradiation for 300 h. The degradation rate can be controlled by changing the content of TiO2 nanoparticles in PE plastic. The degradation of composite plastic initiated on PE-TiO2 interface and then extended into polymer matrix induced by the diffusion of the reactive oxygen species generated on TiO2 particle surface. The present study demonstrates that the polymer-TiO2 compositing is a practical and promising way to degrade the plastic waste under solar light without any pollution.

Zongwei Li

Papers

Solid-phase photocatalytic degradation of polyethylene plastic under UV and solar light irradiation

Enhancement of photocatalytic degradation of polyethylene plastic with CuPc modified TiO2 photocatalyst under solar light irradiation

Direct radiative recombination in the Se-terminated nanoscale Si porous structure