Arginine-Functionalized Thin Film Composite Forward Osmosis Membrane Integrating Antifouling and Antibacterial Effects.

Membrane fouling is an inevitable obstacle of polyamide composite forward osmosis (FO) membranes in oily wastewater treatment. In this study, zwitterionic arginine (Arg) is grafted onto nascent self-made FO polyamide poly(ether sulfone) (PA-PES) membrane, imparting superior hydrophilic, antifouling, and antibacterial properties to the membrane. Detailed characterizations revealed that the Arg-modified (Arg-PES) membrane presented obviously surface positively charged and unique morphology. Results showed that our strategy endowed the optimized membrane, the water flux increased by 113.2% compared to the pristine membrane, respectively, meanwhile keeping high NaCl rejection > 93.9% (with DI water as feed solution and 0.5 M NaCl as draw solution, FO mode). The dynamic fouling tests indicated that the Arg-PES membranes exhibited much improved antifouling performance towards oily wastewater treatment. The flux recovery ratios of the membrane were as high as 92.0% for cationic emulsified oil (cetyl pyridinium chloride, CPC), 87.0% for neutral emulsified oil (Tween-80), and 86.0% for anionic emulsified oil (sodium dodecyl sulfate, SDS) after washing, respectively. Meanwhile, the Arg-PES membranes assembled with guanidine cationic groups exhibited an enhanced antibacterial property against E. coli, which exhibited a high antibacterial efficiency of approximately 96%. Consequently, the newly arginine functionalized FO membrane possesses impressive antifouling performance, while simultaneously resisting bacterial invasion, thus rendering it an ideal alternative for oily wastewater treatment in the FO process.

Sustainable green conversion of coal gangue waste into cost-effective porous multimetallic silicate adsorbent enables superefficient removal of Cd(II) and dye.

Converting solid wastes into new materials for wastewater decontamination is a feasible "one stone, three birds" strategy to achieve sustainable value-added utilization of resources and minimize waste emissions, but significant challenges remain. In response to this, we proposed an efficient "mineral gene reconstruction" method to synchronously transform coal gangue (CG) into a green porous silicate adsorbent without using any harmful chemicals (i.e., surfactants, organic solvents). The one of the synthesized adsorbents with a high specific surface area (582.28 m2/g) and multimetallic active centres shows outstanding adsorption performance (adsorption capacities: 168.92 mg/g for Cd(II), 234.19 mg/g for methylene blue (MB); removal rate: 99.04% for Cd(II) and 99.9% for MB). The adsorbent can also reach a high removal rate of 99.05%∼99.46% and 89.23%∼99.32% for MB and Cd(II) in real water samples (i.e., Yangtze River, Yellow River, seawater and tap water), respectively. After 5 adsorption-desorption cycles, the adsorption efficiency remained above 90%. The adsorbents mainly adsorbed Cd(II) by electrostatic attraction, surface complexation and partial ion exchange and MB by electrostatic and hydrogen bonding interactions. This study provides a sustainable and promising platform for developing a new-generation cost-efficient adsorbent from waste for clean water production.

Evaluating environmental outcome and process-adaptivity of regional collaboration: An empirical study from China.

Since the 2000s, China has enforced regional collaboration as a way of resolving cross-diffused air pollution and jurisdictional limitations. It is, however, a hotly debated issue as to whether authority-driven regional collaboration can be sustained and effective, and no consensus has been achieved by the theoretical discussion. Despite extensive empirical research on the topic, most studies judged the sustainability of collaborations by analyzing the environmental outcomes within a short period after their initiation. To provide more comprehensive empirical evidence to the open question, this paper introduces the criterion of adaptivity to determine whether collaboration is sustainable. Taking the changing collaboration in Beijing-Tianjin-Hebei and its surroundings as a quasi-natural experiment, Difference-in-Difference model and Triple Difference Model are used to verify the adaptivity from two aspects. Results show that authority-driven collaboration adjustment yields better environmental outcomes. Additionally, the better environmental outcome is observed in original collaborators, implying that local governments can learn by doing and form interdependence through repeated collaborative actions. The adaptive collaboration, however, has two limitations. First, the collaboration mechanism is formed primarily based on performance evaluation and target assessment instruments, without showing adaptivity in reducing soft control indicators of air pollution. Second, the different regulation pressure between non-collaborating and collaboration cities results in undesirable spillover effects within a range of 40-100 km. This study not only contributes to empirical and theoretical studies on regional collaboration but also provides support to the improvement of the collaboration system in practice.