Aging Characteristics and Ecological Effects of Primary Microplastics in Cosmetic Products Under Different Aging Processes.

Microplastics are becoming an increasingly environmental concern, but only a few studies have focused on primary microplastics. Herein, four primary microplastics (Lapis, Jade, Topaz and White) commonly used in cosmetic products were selected to investigate the effects of sunlight, seawater, and soil aging on their environmental behaviors. After sunlight and seawater aging, the surfaces of all four microplastics developed breaks and cracks, with particle sizes decreased and specific surface areas increased. Topaz exhibited the most significant changes under sunlight and seawater aging and its maximum adsorption capacity of phenanthrene significantly increased by 22.50% and 47.86%, respectively. Under soil aging, amending with either White or Topaz changed the soil bacterial community composition and diversity, but they had less ecological impacts than polyvinyl chloride plastic. The results of this study provide vital information for understanding the aging characteristics, environmental behavior, and ecological effects of primary microplastics under natural aging processes.

Enhanced and selective phototransformation of chlorophene on aluminum hydroxide-humic complexes.

Mineral-humic complexes, known as mineral-associated organic matter (MAOM), are ubiquitous in natural waters. However, the interaction between organic pollutants and MAOM remains elusive, which may affect their degradation process. In this study, photochemical transformation of chlorophene (CP) in the presence of MAOM, prepared by coating aluminum hydroxide with humic acid (HA-HAO), was investigated. Our results showed that the degradation of CP was significantly enhanced in the presence of HA-HAO, and the degradation rate constant was ~5 times as that with HA only. It was because the adsorption of CP to HA-HAO particles was greatly enhanced, and concentration of reactive oxygen species (ROS) was increased on HA-HAO surfaces, which further promoted the reactions between CP and ROS. The quenching experiments combined with EPR technology confirmed that superoxide anion (O2·-) was the primary reactive radical on CP photodegradation. More importantly, the degradation of CP with HA-HAO followed a hydroxylation process, rather than the oligomerization reaction with HA only. Spectroscopic analysis provided direct evidence for the formation of hydrogen bonding between CP phenolic hydroxyl group and surface oxygen of HAO, which would suppress the reactivity of phenolic hydroxyl group, consequently the ortho- and meta-positions of CP became more facile for the hydroxylation reaction. This study shows the importance of MAOM in altering the photochemical behavior and transformation pathway of organic contaminants.