Due to the high carcinogenicity and bioaccumulation effects of dichromate ions in the human body, sensitive and rapid detection of Cr 2 O 7 2− ions is necessary. Herein, two lanthanide coordination polymers based on a linear dicarboxylic acid ligand, named {Ln(cpon)(Hcpon)(H 2 O) 3 } n [Ln = Tb, Tbcpon; Eu, Eucpon; H 2 cpon = 5-(4-carboxy-phenoxy)-nicotinic acid], have been successfully synthesized. These two isostructural compounds contain one-dimensional zigzag chains that consist of uncoordinated carboxyl groups and pyridine groups in the framework, and the onedimensional chains can further form a three-dimensional supramolecular stacking structure by intermolecular interaction. Both Tbcpon and Eucpon show good luminescence performance and high stability. Tbcpon exhibits a good ability to sense Cr 2 O 7 2− ions in aqueous solution. Moreover, the composite film material composed of Tbcpon and poly(methyl methacrylate) (PMMA) exhibits superior luminescence properties compared to those of pure Tbcpon. The Tbcpon-PMMA film exhibits an excellent ability to recognize Cr 2 O 7 2− ions with high selectivity and a low detection limit of 5.6 ppb, which is much lower than the maximum contamination standard of 100 ppb in drinking water specified by the U.S. Environmental Protection Agency. Furthermore, the Tbcpon-PMMA film shows good recyclability for more than five cycles and anti-interference ability. After the introduction of the slightly soluble polymer poly(vinyl alcohol) (PVA), the Tbcpon-PVA composite film can effectively detect Cr 2 O 7 2− ions in as little as 1 min. These composite films could be potentially used as test strips for trace detection and rapid detection of Cr 2 O 7 2− ions in aqueous solution.

Microwave discharge plasma using catalyst-assisted active coke (Fe/AC, Mn/AC, Cu/AC) provides high performances for NO reduction at lower power (200 W) in this study. Results show that the effect of plasma and catalysis not only enhances the ability of plasma to remove NO, but also reduces the energy consumption of reaction; especially, Fe/AC increased the removal efficiency by nearly 64.8% compared with original coke. Plasma intensity was enhanced with the polarization increased by catalysts, giving better denitration performance. All the metal oxides studied catalyze the NO–carbon reaction, and the metal oxides had the tendency to be reduced. What is more, the catalysts increase the polarization of active coke, accelerating the rate of the temperature rise in the microwave field and increase the content of oxygen-containing functional groups, thereby promoting the C–NO reaction.