Performance investigation of poly(vinylidene fluoride-cohexafluoropropylene) membranes containing SiO2 nanoparticles in a newly designed single vacuum membrane distillation system.

The current study focuses on the development of a superhydrophobic poly(vinylidene fluoride-cohexafluoropropylene) nanocomposite membrane suitable for vacuum membrane distillation by incorporating SiO2 nanoparticles. At loading hydrophobic nano-SiO2 particle concentration (0.50-1.50 wt.%), the developed nanocomposite membranes are optimized in terms of vacuum membrane distillation performance. The influence of temperature, vacuum pressure, and feed water flow is studied for desalinating high-salinity brine. The results show that the developed vacuum distillation membrane is capable of 95% salt rejection during the treatment of a highly saline feed (65,000 ppm) at fixed flow rates of 120 L/h saline feed and different operating conditions consisting of feed inlet temperatures ranging from 40°C to 70°C and distillate inlet temperatures of 7-15°C. The vacuum membrane distillation process achieves 0.38-1.66% water recovery with increasing concentration factor, meaning that recovery is increased, and shows a specific electrical energy consumption of 5.16-23.90 kWh/m3 for product water. Overall, the newly designed membrane demonstrates suitability for a vacuum membrane distillation system. PRACTITIONER POINTS: Desalinate high-salinity brine (TDS > 35,000 ppm) using a vacuum membrane distillation system. A hydrophobic PVDF-HFP/SiO2 nanocomposite membrane development for vacuum membrane distillation. A newly designed single vacuum membrane distillation system for RO brine treatment.

Boron Removal by Membrane Distillation: A Comparison Study.

Several Membrane Distillation (MD) technologies have been employed to remove boron from various concentrations. In this study, Vacuum Membrane Distillation (VMD), Permeate Gap Membrane Distillation (PGMD), and Air Gap Membrane Distillation (AGMD) are examined to evaluate their effectiveness when combined with several boron concentrations (1.5, 7 and 30 ppm) and operating parameters (circulation rate from 0.9 L/min to 5 L/min, feed temperature from 40 to 70 °C, and pH from 3-11). Those concentrations of boron are selected on the basis of the concentration of boron in the permeate side of the single-pass reverse osmosis (RO) system, Arabian Gulf, and contaminated brackish water. Moreover, synthetic seawater is treated to assess MD technologies' effectiveness. A high removal efficiency of boron is accomplished by MD. AGMD, PGMD, and VMD are promising methods for the desalination industry. AGMD shows excellent boron removal, which was above 99% with a wide ranging concentration. In addition, VMD demonstrates good permeate flux compared to the other MD technologies, which were about 5.8 kg/m2·h for synthetic seawater. Furthermore, there is no noteworthy influence of the pH value on the boron removal efficiency.

Ceramic Microfiltration Membranes in Wastewater Treatment: Filtration Behavior, Fouling and Prevention.

Nowadays, integrated microfiltration (MF) membrane systems treatment is becoming widely popular due to its feasibility, process reliability, commercial availability, modularity, relative insensitivity in case of wastewater of various industrial sources as well as raw water treatment and lower operating costs. The well thought out, designed and implemented use of membranes can decrease capital cost, reduce chemical usage, and require little maintenance. Due to their resistance to extreme operating conditions and cleaning protocols, ceramic MF membranes are gradually becoming more employed in the drinking water and wastewater treatment industries when compared with organic and polymeric membranes. Regardless of their many advantages, during continuous operation these membranes are susceptible to a fouling process that can be detrimental for successful and continuous plant operations. Chemical and microbial agents including suspended particles, organic matter particulates, microorganisms and heavy metals mainly contribute to fouling, a complex multifactorial phenomenon. Several strategies, such as chemical cleaning protocols, turbulence promoters and backwashing with air or liquids are currently used in the industry, mainly focusing around early prevention and treatment, so that the separation efficiency of MF membranes will not decrease over time. Other strategies include combining coagulation with either inorganic or organic coagulants, with membrane treatment which can potentially enhance pollutants retention and reduce membrane fouling.