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A new type of carbonized polymer dot was prepared by the one-step hydrothermal method of triethoxylsilane (TEOS) and citric acid (CA). The sensor made from carbonized polymer dots (CPDs) showed superior gas sensing performance toward ammonia at room temperature. The Si, O-codoped CPDs exhibited superior ammonia sensing performance at room temperature, including a low practical limit of detection (pLOD) of 1 ppm ( R a : 1.10, 1 ppm), short response/recovery time (30/36 s, 1 ppm), high humidity resistance (less than 5% undulation when changing relative humidity to 80 from 30%), high stability (less than 5% initial response undulation after 120 days), reliable repeatability, and high selectivity against other interferential gases. The gas sensing mechanism was investigated through control experiments and in situ FTIR, indicating that Si, O-codoping essentially improves the electron transfer capability of CPDs and synergistically dominates the superior ammonia sensing properties of the CPDs. This work presents a facile strategy for constructing novel high-performance, single-component carbonized polymer dots for gas sensing.R g : 1.10, 1 ppm), short response/recovery time (30/36 s, 1 ppm), high humidity resistance (less than 5% undulation when changing relative humidity to 80 from 30%), high stability (less than 5% initial response undulation after 120 days), reliable repeatability, and high selectivity against other interferential gases. The gas sensing mechanism was investigated through control experiments and in situ FTIR, indicating that Si, O-codoping essentially improves the electron transfer capability of CPDs and synergistically dominates the superior ammonia sensing properties of the CPDs. This work presents a facile strategy for constructing novel high-performance, single-component carbonized polymer dots for gas sensing.

In this study, colorimetric indicator films (CIFs) were developed by integrating neutral red covalently immobilized onto TEMPO-oxidized cellulose nanofibrils (NR@TOCNFs) and poly(acrylic acid) (PAA) inside a poly(vinyl alcohol) (PVA) matrix. The successful covalent immobilization of NR onto the TOCNFs was confirmed using attenuated total reflection-Fourier transform infrared, X-ray photoelectron spectroscopy, and thermogravimetric analyses. The CIFs had a visible color change from red to yellow as the pH changed from 2.0 to 10.0. The colorimetric response of CIFs improved as the NR@TOCNF content increased, while it decreased as the PAA level increased. The critical pH ranges for the color change of CIFs were 6-7, 7-8, and 8-9 for 3 %, 5 %, and 7 % PAA, respectively, at 0.3 % NR@TOCNF. The best ammonia sensitivity was found in the indicator films containing 3 % PAA and 0.3 % NR@TOCNF. These results showed that the CIFs could be applied for freshness detection in food packaging., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

This study reported two-phase electrochemical processes, including struvite electrochemical precipitation and ammonia electrooxidation, for the treatment of supernatant from the hydrolysis sludge. The results showed that in phase I, the removal efficiencies of 92.3% PO 4 3- -P and 50.1% NH 4 + -N could be achieved in electrochemical precipitation with magnesium sacrificial anode at pH 9.0 and 40 mA after 120-min electrolysis, and slightly increased to 95.1% and 57.3%, respectively, when current further increased to 120 mA, while the energy consumption (ECS, from 0.6 to 6.7 kWh m -3 ) and specific energy consumption [SECS, from 2.7 to 29.9 Wh g (PO 4 3- -P) -1 ] sharply increased. In phase II, the residual NH 4 + ]. The results indicated that current were the crucial factors; meanwhile, lower current and longer reaction time may be the optimal options in electrochemical process with higher efficiency and lower energy consumption. Finally, the integrated process was conducted at the optimal conditions (pH = 9.0, I = 40 mA in phase I; Cl/N = 5, I = 50 mA in phase II) with the supernatant of the alkaline hydrolysis sludge. Removal of ammonia nitrogen (79.3%) and removal of phosphorus (94.3%) were achieved, confirming the feasibility of practical application for the simultaneous phosphorus recovery and ammonia removal.2 -Sb-Pd). With the generation of active chloride, about 83.2% NH 4 + -N was removed with the molar ratio of Cl/N 5:1 at 50 mA after 120-min treatment, and slightly increased to 92.2%, when current increased to 125 mA, while SECS significantly increased [from 0.027 to 0.117 kWh g (NH 4 + -N) -1 ]. The results indicated that current were the crucial factors; meanwhile, lower current and longer reaction time may be the optimal options in electrochemical process with higher efficiency and lower energy consumption. Finally, the integrated process was conducted at the optimal conditions (pH = 9.0, I = 40 mA in phase I; Cl/N = 5, I = 50 mA in phase II) with the supernatant of the alkaline hydrolysis sludge. Removal of ammonia nitrogen (79.3%) and removal of phosphorus (94.3%) were achieved, confirming the feasibility of practical application for the simultaneous phosphorus recovery and ammonia removal.