Search

A green method for safety drinking water production was proposed in this study by the development of a positively charged nanofiltration (PNF) membrane composed of two different functional layers. Glycosyl layer was fabricated through interfacial polymerization in which the performances of sucrose doped NF membrane was superior to the glucose and raffinose doped membranes, which were further enhanced by alkali treatment. Sucrose (0.8 wt%) and NaOH (0.05 mol‧L−1) benefit the formation of higher porosity and better hydrophilicity and offer a high pure water flux (13.5 L m−2 h−1·bar−1) and Na 2 SO 4 rejection (99.3%). Then, the PNF membrane was acquired by coating polyethyleneimine (PEI) on the sucrose-polyamide layer. The concentration of PEI and grafting time were both studied and the optimal membrane showed an excellent performance for heavy metals removal. The as-developed membrane has found its potential application in drinking water purification which gave 90% rejection for heavy metals and the permeance reached to 7.4 L m−2 h−1·bar−1. With the proposed method, the trace elements were retained partially which was beneficial to the human body and the toxic metals were kept within the limits. Image 1 • Positive charged NF membrane with dual functional layers was proposed. • Glucose, sucrose and raffinose were used to form negatively charged layer. • Sucrose and NaOH offer higher porosity, better hydrophilicity and separation ability. • PEI coated TFC membrane has excellent heavy metals removal ability and stability. • The positively charged membrane exhibited well in drinking water purification. [ABSTRACT FROM AUTHOR]

Active layers with outstanding organic solvent nanofiltration (OSN) performances were designed novelly by adopting host-guest (HG) interaction to realize adamantane structure immobilization. During the fabrication process, β -cyclodextrin (β -CD) served as the "host" while adamantylamine/adamantanemethylamine (AMA/AMmA) worked as the "guest". Stechiometrical experiment results demonstrated that one half molar ratio of the "guest" to the "host" molecular (1.0%, w/v) led to the best OSN performance. The successful immobilization of adamantane structure was verified by XPS , FT-IR and EDX results, and the adamantane immobilized membrane showed weakened "nodule-like" pattern and reduced surface roughness values compared with the control membrane. Acetone, for the first time, was proposed as the activation solvent for enhancement of OSN performance. After acetone activation, the morphology and topography of the adamantane immobilized membranes seldom changed but their pure methanol (MeOH) flux were quintupled (29.0 ± 2.6 L m−2 h−1) and the rose bengal (RB) removed from MeOH reached to 98.2 ± 0.1%. Those HG complexes also resulted in the reduction of molecular weight cut-off (MWCO) values from 466.6 Da to 436.9 and 428.4 Da of PCA10 1/2 + and PCAm10 1/2 +, respectively. Besides, the PCAm10 1/2 + demonstrated excellent OSN performances in the long-term operation of active pharmaceutical ingredients (APIs) concentration of clarithromycin (CLA)/acetone. Novel designed active layer immobilized adamantane structure with outstanding stability and membrane performances for organic solvennt nanofiltration (OSN). Image 1 • Host-guest chemistry was firstly utilized in OSN membrane development. • Adamantane structure was successfully immobilized into the active layer. • Activation of the OSN membrane using pure acetone was firstly proposed. • The mechanism of experimental errors of MWCO values was illuminated. • Outstanding performance in the potential application of API concentration was made. [ABSTRACT FROM AUTHOR]