Metal-organic frameworks (MOFs) are studied for the design of advanced nanocomposite membranes, primarily due to their ultrahigh surface area, regular and highly tunable pore structures, and favorable polymer affinity. However, the development of engineered MOF-based membranes for water treatment lags behind. Here, thin-film nanocomposite (TFN) membranes containing poly(sodium 4-styrenesulfonate) (PSS) modified ZIF-8 (mZIF) in a polyamide (PA) layer were constructed via a facile interfacial polymerization (IP) method. The modified hydrophilic mZIF nanoparticles were evenly dispersed into an aqueous solution comprising piperazine (PIP) monomers, followed by polymerizing with trimesoyl chloride (TMC) to form a composite PA film. FT-IR spectroscopy and XPS analyses confirm the presence of mZIF nanoparticles on the top layer of the membranes. SEM and AFM images evince a retiform morphology of the TFN-mZIF membrane surface, which is intimately linked to the hydrophilicity and adsorption capacity of mZIF nanoparticles. Furthermore, the effect of different ZIF-8 loadings on the overall membrane performance was studied. Introducing the hydrophilizing mZIF nanoparticles not only furnishes the PA layer with a better surface hydrophilicity and more negative charge but also more than doubles the original water permeability, while maintaining a high retention of NaSO. The ultrahigh retentions of reactive dyes (e.g., reactive black 5 and reactive blue 2, >99.0%) for mZIF-functionalized PA membranes ensure their superior nanofiltration performance. This facile, cost-effective strategy will provide a useful guideline to integrate with other modified hydrophilic MOFs to design nanofiltration for water treatment.

Surface zwitterionization of graphene oxide (GO) was firstly conducted by grafting poly(sulfobetaine methacrylate) (PSBMA) onto the GO surface via reverse atom transfer radical polymerization (RATRP).

Two-dimensional nanomaterials are rapidly emerging as promising building blocks for the design of molecular sieving membranes with remarkable separation performance.

Fabrication of MOF functionalized PA membranes with crumpled fishnet-like structures used for nanofiltration with rapid water transport and superior mono/divalent salt selectivity.

ObjectiveTo identify the facilitators and barriers to implement family doctor contracting services in China by using Consolidated Framework for Implementation Research (CFIR) to shed new light on establishing family doctor systems in developing countries.DesignA qualitative study conducted from June to August 2017 using semistructured interview guides for focus group discussions (FGDs) and individual interviews. CFIR was used to guide data coding, data analysis and reporting of findings.Setting19 primary health institutions in nine provinces purposively selected from the eastern, middle and western areas of China.ParticipantsFrom the nine sampled provinces in China, 62 policy makers from health related departments at the province, city and county/district levels participated in 9 FGDs; 19 leaders of primary health institutions participated in individual interviews; and 48 family doctor team members participated in 15 FGDs.ResultsBased on CFIR constructs, notable facilitators included national reform involving both top-down and bottom-up policy making (Intervention); support from essential public health funds, fiscal subsidies and health insurance (Outer setting); extra performance-based payments for family doctor teams based on evaluation (Inner setting); and positive engagement of health administrators (Process). Notable barriers included a lack of essential matching mechanisms at national level (Intervention); distrust in the quality of primary care, a lack of government subsidies and health insurance reimbursement and performance ceiling policy (Outer setting); the low competency of family doctors and weak influence of evaluations on performance-based salary (Inner setting); and misunderstandings about family doctor contracting services (Process).ConclusionsThe national design with essential features including financing, incentive mechanisms and multidepartment cooperation, was vital for implementing family doctor contracting services in China. More attention should be paid to the quality of primary care and competency of family doctors. All stakeholders must be informed, be involved and participate before and during the process.