Designing of a novel polyvinylidene fluoride/TiO2/UiO-66-NH2 membrane with photocatalytic antifouling properties using modified zirconium-based metal-organic framework.

Novel polyvinylidene fluoride/TiO2/UiO-66-NH2 (PVDF/TiUN) membranes were produced by the delay phase separation method via introducing the TiO2/UiO-66-NH2 (TiUN) nanocomposite into PVDF casting solution. Interconnection of TiO2 and UiO-66-NH2 improved photocatalysis capacity and endowed PVDF/TiUN membranes with self-cleaning capability. Quantitative measurements showed that, firstly, PVDF/TiUN membranes exhibited improved photodegradation kinetics and efficiency (up to 88.1%) to Rhodamine B (RhB). Secondly, the performances of bovine serum albumin (BSA) rejection and permeation of PVDF/TiUN membranes outperformed those of other check samples, indicating enhanced hydrophilicity. Thirdly, rejection rate of BSA reached a breathtaking 98.14% and flux recovery ratio (FRR) of BSA reached a breathtaking 95.37%. Thus, given their excellent anti-contamination property and separation performance, the PVDF/TiUN membrane is very likely to be a novel water treatment membrane.

Self-adhesive PMIA membranes with chitosan porous beads immobilized pullulanase for efficient biological aging of beer.

A novel pulluanase@chitosan porous beads/Poly (m-phthaloyl-m-phenylenediamine) (PULL@CPB/PMIA) membrane with good separation and biocatalysis properties was prepared by a self-adhesive method by introducing an immobilized enzyme (PULL@CPB) onto the PMIA membrane. The combination of PULL@CPB and PMIA could increase the one-step refining of protoplasmic beer as well as the ability of biocatalysis to lower the alcohol-to-ester ratio. The experimental results showed that the addition of PULL@CPB and the increase in the ratio of EtOH/water in the coagulation bath both increased the load of pullulanase on the membrane surface, while excessive addition decreased the activity of pullulanase. Under the amount of PULL@CPB is 0.5 g·L-1 and the ratio of EtOH/water is 60%, the relative activity of pullulanase in PULL@CPB modified PMIA membrane was the highest, which was 91.7% of the initial activity. The interception rates of protein and macromolecular ß-glucan were 92.2% and 87.3%, respectively, under the condition of beer flux (162.3 L·m-2·h-1). At the same time, the PULL@CPB/PMIA membrane has strong antibacterial performance and thus plays a role in extending the shelf life of beer. Compared with free pullulanase, the thermal stability, pH stability, organic solvent stability, and storing stability of immobilized pullulanase were significantly improved. The effects of PULL@CPB dosage and operating temperature on biocatalysis efficiency were discussed. The immobilized pullulanase activity on the membrane remained at 70.8% after 10 continuous uses. Therefore, the PMIA membrane is an excellent carrier of pullulanase, so its bioactive membrane has a wide range of prospects in food, medicine, and other fields.

Sustainable membrane operation design for the treatment of the synthetic coke wastewater in SMBR.

Membrane fouling in the membrane bioreactor (MBR) is typically caused by the interaction of microbial characteristics, hydrodynamic behavior, operation environment, wastewater characteristics and membrane properties, which result in the deterioration of performance and increasing energy consumption and cost of membrane replacement. The effect of the crucial MBR parameters (the microbial loading and characteristics, dissolved oxygen (DO), hydraulic retention time (HRT), backwashing conditions and membrane characteristics) on membrane fouling was investigated in a submerged membrane bioreactor (SMBR) during the long term treatment of synthetic coke wastewater. Also the optimum operation strategies were further utilized in order to satisfy the minimal membrane fouling operation through a long-term evaluation of the MBR performance. It has been demonstrated that with application of these optimal designed conditions, significant membrane fouling improvements were achieved over a long operating time, so it was possible to perform in sustainable operation for MBR. In this study, the upper limit of the sustainable flux is found to be as much as 18.6 L/m(2) h and the optimum sustainable flux value should be 50 approximately 75% of critical flux to satisfy the desired sustainable operation period.