Constructing an acidic microenvironment by sulfonated polymers for photocatalytic reduction of hexavalent chromium under neutral conditions.

Hexavalent chromium (VI) heavy metal contamination is considered a serious threat to human health and the environment. The photocatalytic reduction of Cr(VI) basically occurs in the acidic environment, severely limiting the application of photocatalysts for the reduction of Cr(VI). Therefore, we designed a microenvironment strategy to achieve efficient reduction of Cr (VI) under neutral conditions by introducing sulfonic acid onto the aromatic conjugated skeleton. A series of characterizations and experiments have shown that the sulfonated aromatic ring conjugated polymer (Arcp-SO3H) can efficiently remove Cr(VI) under neutral or even alkaline conditions. In neutral solutions, Arcp-SO3H has a rate constant of 0.054 min-1 within 90 min and has an efficiency of nearly 100 %, which is 16 times faster than before sulfonation (k = 0.0316 min-1). the Arcp-SO3H surpasses all organic polymers and most metal-based photocatalysts in the related field. The capture experiments have proved that •O2- is the main role of reducing Cr(VI), and e- is secondary, which is quite different from the mechanism reported in the previous literature. The efficiency of reducing Cr (VI) in the four-cycle experiment is still 96 %, which also proves that Arcp-SO3H has strong stability and reproducibility. Thus, Arcp-SO3H has great practical application potential in the treatment of wastewater, and microenvironmental strategies also offer new possibilities in the field of environmental remediation.

UV-assisted ultrafast construction of robust Fe3O4/polydopamine/Ag Fenton-like catalysts for highly efficient micropollutant decomposition.

Fenton-like catalysts represent a family of promising materials to degrade micropollutants from contaminated water. However, the practical applications of Fenton-like catalysts are mainly limited by low catalytic degradation efficiency and stability. Herein, for the first time, rapid fabrication of Ag-decorated Fe3O4/polydopamine (FPA) microspheres was achieved via the help of UV irradiation, and the designed FPA microspheres were employed as Fenton-like catalysts to degrade micropollutants. Results showed that UV irradiation could activate the generation of the polydopamine shell and accelerate the Ag deposition, which played a crucial role in the rapid synthesis of highly active and stable FPA catalysts. Relative to reported catalysts, these FPA microspheres exhibited outstanding catalytic degradation performance, achieving 94.38% removal of tetracycline within 60 min. This work will provide a convenient strategy in the sustainable and efficient purification of wastewater to improve the quality of human life.

Heteroatom-free conjugated tetraphenylethylene polymers for selectively fluorescent detection of tetracycline.

The antibiotic tetracycline (Tc) is a major contaminant in food and water, with adverse effects on both ecosystems and human health. The development of novel sensors for tetracycline detection is of great importance. In this work, we develop a novel heteroatom-free conjugated tetraphenylethylene polymer (TPE-CMP) fluorescence sensor for the detection of tetracycline. In the presence of Tc, the emission fluorescence of TPE-CMP was quenched by the photoinduced electron transfer mechanism to achieve high sensitivity. The polymers can detect tetracycline at a concentration of 0-100 µg/mL with a good linear correlation (0.99), and the limit of detection (LOD) is 1.23 µg/mL. Furthermore, TPE-CMP has excellent selectivity in detecting Tc in the presence of various anti-interference analytes, including ions and antibiotics. In addition, the practical feasibilities of TPE-CMP for Tc sensing were further investigated in milk, urine and wastewater samples with satisfactory recoveries (from 94.96% to 112.53% for milk, from 96.41% to 99.31% for urine and from 98.54% to 100.52% for wastewater). We have designed and synthesized TPE-CMP based on heteroatom-free for the specific fluorescence detection of tetracycline, expanding the range of fluorescence detection sensors and offering great promise for practical applications.