Polyamide (PA) based thin-film nanocomposite (TFN) membranes containing zeolitic imidazolate framework (ZIF) particles, denoted as PA (ZIF)-TFN membranes, were fabricated via interfacial polymerization (IP) between m-phenylenediamine (MPD) and 1,3,5-benzenetricarbonyl chloride (TMC). ZIF-8 particles were incorporated by direct dispersion into the oil-phase solution. Subsequently, the membranes were etched with xylenol orange disodium salt (XO) under acidic conditions to produce reverse osmosis (RO) membranes with improved water flux and salt rejection. These improvements were attributed to additional water-permeation channels and the sealing of non-selective interface defects. Solution pH, etching duration, and XO concentration also play roles in the structure and performance of the optimized RO membranes. After 12 h of etching, superior TFN/XO (12) RO membranes were obtained with rejection rate increased from (99.0% ± 0.2%) to (99.7% ± 0.1%), and water flux increased from (42.3 ± 0.9 L·m −2 ·h −1 ) to (65.1 ± 0.9 L·m −2 ·h −1 ). In addition, the membranes exhibited excellent boron removal rate, operational stability, and anti-pollution performance under conditions of 32,000 ppm NaCl and 55 bar.
Wang You,Huo Danqun,Wu Huixiang,Li Jaiwei,Zhang Qinghai,Deng Bo,Zhou Jing,Yang Mei,Hou Changjun
Carboxylic acids (CAs) have been reported as potential biomarkers of specific diseases or human body odors. A visual sensor array is described here that is based on indicator displacement assays (IDAs). The arrays were prepared by spotting solutions of the following metal complexes: Murexide-Ni(II), murexide-Cu(II), zincon-Zn(II) and xylenol orange-Cu(II), with the capability of discrimination of 15 carboxylic acids (CAs) and the quantitation of pyruvic acid (PA). Clear differences can be observed through distinctive difference maps obtained within 5 min by subtraction of red, green and blue (RGB) values of digital images after and before exposure to analytes. After an analysis of multidimensional data by pattern recognition algorithms including HCA, PCA and LDA, excellent classification specificity, and accuracy of >96% were obtained for all samples. The IDA array exhibited a linear range from 10 to 1500 μM with a theoretical detection limit of 3.5 μM towards PA. Recoveries of real samples varied from 84.8% to 114.3%. As-fabricated IDA sensor array showed an excellent selectivity among other organic interfering substances and a good batch to batch reproducibility, demonstrating its robustness. All these observations suggested that the IDA sensor array is one of the most promising paths for the discrimination of CAs.
Schematic diagram of indicator displacement assay (a), the procedure for acquisition of difference maps (b), and pattern recognitions for CAs (c). The method uses hierarchical cluster analysis (HCA), principal component analysis (PCA) and linear discriminant analysis (LDA)
Hu-Wei Lv,Hong-Liu Jiang,Fu-An He,Qing-Di Hu,Zhu-Rui Zhong,Yong-Yu Yang
A novel crosslinked cellulose-tetrafluoroterephthalonitrile-tannin (CETTA) polymer with the excellent adsorption performance for both cationic and anionic dyes was synthesized by a one-step reaction, and its structure was investigated by SEM, FTIR, TGA, XPS, and zeta potential measurement. It was found that the adsorption ability of the CETTA changed with the pH value of the dye solution because the electrostatic interaction played an important role in the dye adsorption process. The maximum adsorption capacities of the CETTA at 303 K for the cationic methylene blue (MB) and the anionic xylenol orange (XO) dye reached as high as 953 mg/g at pH = 10 and 232 mg/g at pH = 1, respectively. The adsorption behaviors of the CETTA for both the MB and the XO were not only spontaneous but also in accordance with the pseudo-secondary adsorption kinetic model and the linear Langmuir adsorption isotherm model. Additionally, the CETTA possessed the good reused ability for the dye adsorption.
危险品化学品经营许可证（带存储）