Jiuyun Cui

Accelerating the design of multi-component nanocomposite imprinted membranes by integrating a versatile metal–organic methodology with a mussel-inspired secondary reaction platform

Efforts to engineer novel membrane materials with enhanced anti-fouling and comprehensive properties as well as highly selective separation abilities are hampered by the lack of effective imprinted cavities and structure stability. In this work, a novel multi-component metal–organic nanocomposite imprinted membrane (MMO-MIM) has been prepared by integrating a bioinspired metal–organic methodology with the secondary surface sol–gel imprinting technique. The synthesis pathway of MMO-MIM involves two steps: initially, a self-polymerized polydopamine process followed by hydrolysis with ammonium fluotitanate on the surface of the PVDF membrane, a surface-initiated sol–gel imprinted procedure is then conducted on the obtained bio-adhesive nano-sized TiO2 surface system for the fabrication of MMO-MIM. Attributed to the formation of the multilayered membrane structure, stronger fouling resistance and largely enhanced adsorption capacities have been obtained in this case. Meanwhile, the as-prepared MMO-MIM not only exhibits rapid adsorption dynamics, but also possesses excellent separation performance (βMMO-MIM/MMO-NIM and βm-cresol/2,4-DP are higher than 2.6 and 4.0, respectively) of templates. In addition, all synthesis procedures were conducted in aqueous or ethanol solution at ambient temperature, which was environmental friendly for scaling up without causing pollution.

Bioinspired synthesis of high-performance nanocomposite imprinted membrane by a polydopamine-assisted metal-organic method

Significant efforts have been focused on the functionalization and simplification of membrane-associated molecularly imprinted materials, which can rapidly recognize and separate specific compound. However, issues such as low permselectivity and unstable composite structures are restricting it from developing stage to a higher level. In this work, with the bioinspired design of polydopamine (pDA)-assisted inorganic film, we present a novel molecular imprinting strategy to integrate multilevel nanocomposites (Ag/pDA) into the porous membrane structure. The molecularly imprinted nanocomposite membranes were then obtained through an in situ photoinitiated ATRP method by using tetracycline (TC) as the template molecule. Importantly, attributing to the formation of the Ag/pDA-based TC-imprinted layers, largely enhance TC-rebinding capacity (35.41mg/g), adsorption selectivity and structural stability (still maintained 92.1% of the maximum adsorption capacity after 10 cycling operations) could been easily achieved. Moreover, largely enhanced permselectivity performance toward template molecule (the permeability factor β values were also more than 5.95) was also obtained. Finally, all synthesis methods were conducted in aqueous solution at ambient temperature, which was environmental friendly for scaling up without causing pollution.

Bioinspired Synthesis of Photocatalytic Nanocomposite Membranes Based on Synergy of Au-TiO2 and Polydopamine for Degradation of Tetracycline under Visible Light

A bioinspired photocatalytic nanocomposite membrane was successfully prepared via polydopamine (pDA)-coated poly(vinylidene fluoride) (PVDF) membrane, as a secondary platform for vacuum-filtrated Au-TiO2 nanocomposites, with enhanced photocatalytic activity. The degradation efficiency of Au-TiO2/pDA/PVDF membranes reached 92% when exposed to visible light for 120 min, and the degradation efficiency of Au-TiO2/pDA/PVDF membranes increased by 26% compared to that of Au-TiO2 powder and increased by 51% compared to that of TiO2/pDA/PVDF nanocomposite membranes. The degradation efficiency remained about 90% after five cycle experiments, and the Au-TiO2/pDA/PVDF nanocomposite membranes showed good stability, regeneration performance, and easy recycling. The pDA coating not only served as a bioadhesion interface to improve the bonding force between the catalyst and the membrane substrate but also acted as a photosensitizer to broaden the wavelength response range of TiO2, and the structure of Au-TiO2/pDA/PVDF also improves the transfer rate of photogenerated electrons; the surface plasmon resonance effect of Au also played a positive role in improving the activity of the catalyst. Therefore, we believe that this study opens up a new strategy in preparing the bioinspired photocatalytic nanocomposite membrane for potential wastewater purification, catalysis, and as a membrane separation field.

Bio-inspired adhesion: fabrication and evaluation of molecularly imprinted nanocomposite membranes by developing a “bio-glue” imprinted methodology

Nanocomposite membranes with specific recognition, durability and regeneration ability that can rapidly adsorb and separate target compounds have remarkable technological applications for areas ranging from solid-phase extraction devices to architecture. In this work, inspired by the highly bioadhesive performance of mussel protein, urgently desired molecularly imprinted nanocomposite membranes (MINCMs) were prepared by developing a simple “bio-glue” imprinted strategy. By simply immersing the “bio-glue” m-cresol-imprinted PDA@SiO2 into casting solution accompanied by persistently mechanically stirring, a highly bio-adhered and homo-dispersedly distributed structure could be generated into MINCMs during a phase inversion process, which directed the higher perm-selectivity and reusability. Additionally, due to the unique properties of PDA modified layers and SiO2 nanoparticles (high surface-to-volume ratio and large surface area), the as-prepared MINCMs not only exhibited rapid adsorption dynamics, but also possessed an excellent separation performance of template molecule (m-cresol in this work). The excellent separation (perm-selectivity factor is 3.477) and recognition behavior (imprinted factor is more than 3.0) along with the low preparation consumed and green, quick, facile synthesis conditions make the as-prepared MINCMs attractive in broad technological applications for areas ranging from drug delivery to bioseparation.

Fabrication of lithium ion imprinted hybrid membranes with antifouling performance for selective recovery of lithium

With the increasing demand for lithium resources, it is of great significance to develop a new technology for the selective recovery of lithium from complex systems. In the present work, antifouling lithium-imprinted hybrid membranes (LIHMs) were fabricated through a hydrolysis polymerization method using a PVDF/GO hybrid membrane as a basement membrane, and polydopamine as an adhesion layer to anchor imprinted sites. The antifouling experiments demonstrated that LIHMs had the underwater oil contact angle of 152 ± 0.8°. Furthermore, the adsorption isotherms, permeation and adsorption kinetics of the LIHMs were researched in detail. The results displayed that LIHMs showed a distinctive adsorption capacity (27.10 mg g−1) and permselectivity (βK/Li = 5.3780, βCa/Li = 21.9402, βMg/Li = 15.5620) for lithium. Also, the regeneration experiments confirmed the good durability of LIHMs, favoring long-term use. Therefore, the LIHMs provided a powerful tool for the effective separation and recovery of lithium in practical applications.

Development of composite membranes with irregular rod-like structure via atom transfer radical polymerization for efficient oil-water emulsion separation

Development of superhydrophilic, stable and cost-effective composite membranes for efficient oil-water emulsion separation is highly desirable. Herein, an irregular rod-like composite membrane was prepared through 3-aminopropyltriethoxysilane (APTES) modification, followed by acrylamide polymerization with atomic transfer radical polymerization (ATRP). The as-prepared membrane exhibits superhydrophilicity/underwater superoleophobicity due to its irregular rod-like structure and pores-induced capillary actions. The composite membrane has demonstrated sufficient stability in acidic, alkaline and salty environments due to the polymerization of acrylamide. Moreover, the as-prepared composite membrane has effectively separated various oil-water emulsions and demonstrated high permeation and superior flux recovery. The present work demonstrates that the ATRP-assisted composite membrane is a promising material in a wide range of applications, such as industrial wastewater recovery and drinking water treatment.

Synthesis of cauliflower-like ion imprinted polymers for selective adsorption and separation of lithium ion

The recovery of lithium ions from mixed solutions has attracted extensive research interests with increasing demand of lithium resources. In this study, novel cauliflower-like lithium-ion imprinted polymers (Li-IIPs) have been successfully synthesized by using B12C4 as the complexing agent, acrylamide (AM) as the functional monomer and N,N′-methylene bis-acrylamide (MBAM) as the cross linker for selective separation and recovery of lithium ions from mixed solutions. The Li-IIPs exhibited maximum adsorption capacity for Li+ (1.135 mmol g−1) under optimum experimental conditions. Additionally, the high relative selectivity factors (KLi/Na = 5.34, KLi/K = 6.47, KLi/Cu = 23.05, KLi/Zn = 27.13) indicated that Li-IIPs had outstanding selective performance. The regeneration experiments were also conducted and confirmed the favorable reusability and stability of the as-prepared polymers. Therefore, the outstanding performance and simple preparation method makes Li-IIPs a powerful tool for effective separation and recovery of lithium ions in practical applications.

Bioinspired synthesis of multiple-functional nanocomposite platform showing optically and thermally responsive affinity: Application to environmentally responsive separation membrane

A tremendous effort has been made for the synthesis and multifunction of environmentally responsive and selective separation membranes. With the bioinspired design of polydopamine (pDA)-assisted inorganic film, we proposed a simple, yet efficient, thermo-responsive cell culture substrate. Herein, a Ag/TiO2/pDA-based nanocomposite structure was initially obtained, and the ciprofloxacin-imprinted membranes (MINCMs) with thermo-responsive recognition sites were then synthesized by using NIPAm as backbone monomer. The opto-thermally responsive molecularly imprinted membranes (OT-MIMs) were obtained through in situ reduction of HAuCl4 on membrane surfaces, Au nanoparticles were used as the light-heat converters. The light-switching principle was elaborated as well as the energy conversions that took place in this system. These conformational changes finally allowed the constructions or destructions of ciprofloxacin-imprinted sites. Due to the formation of the opto-thermally responsive ciprofloxacin-imprinted sites, rapid adsorption dynamics and opto-thermally responsive perm-selectivity toward templates were both achieved. Therefore, 58.65 mg/g of adsorption capacity and 4.91 of permselectivity factor from OT-MIMs were successfully obtained. Importantly, the as-designed bioinspired strategy led to a state-of-the-art design that was capable of reversibly controlling the flow rate (J) of ciprofloxacin from 12.10 to 4.93 mg min-1 cm-2 in less than a few minutes using light.

Selective separation of bifenthrin by pH-sensitive/magnetic molecularly imprinted polymers prepared by pickering emulsion polymerization

Via Pickering emulsion polymerization, pH-sensitive magnetic molecularly imprinted polymers (HM-MIPs) were synthesized using bifenthrin (BF) as the template molecule, and pH-sensitive monomer methacrylic acid as the functional monomer. Characterizations of HM-MIPs were achieved by FTIR, TGA, TEM, SEM, and VSM, and the results indicated that HM-MIPs exhibited magnetic property (Ms=1.06 emu/g). HM-MIPs were acted as the adsorbent for a series of adsorption performance testing of BF. Equilibrium data were described by the Langmuir and Freundlich isotherm models. Kinetic properties were successfully investigated by pseudo-first-order model, pseudo-second-order model. The selective recognition experiments exhibited outstanding selectively adsorption effect of the HM-MIPs for target BF over diethyl phthalate and fenvalerate. In water, the HM-MIPs could achieve the adsorption and release of BF by controlling the pH value of the aqueous solution. The results indicated that the molecularly imprinted polymers exhibited good adsorption, selectivity and pH-sensitive performance for BF.