Introduction to Fo Membranes

In this study, nutrient removal processes, FO membrane technology, main factors affecting the FO process performance, the source water for nutrient recovery, the previous studies on the FO membrane process for nutrient removal/recovery from wastewater and sludge, membrane fouling, and recent advances in FO membranes for nutrient removal/recovery were briefly and critically reviewed.

As a promising approach, real-time monitoring of fouling layers on the surface of FO membranes and the prediction of fouling layer characteristics using deep learning models can characterize and control membrane fouling in FO and other membrane processes.

We expect that this novel technique can be applied to fabricate TFN-FO membranes with good heavy metal separation performance.

In this study, submerged hollow fiber FO (Sub-HFFO) modules were designed using commercial HFFO membranes.

The results of this study suggest that an advanced pretreatment process to remove bacteria and organic matter is essential for the protection of the FO membranes.

The appropriate loading of GO nanosheets on ENs substrates was proven to be a competitive strategy for developing high-performance ENs based FO membranes.

To fabricate the TFC-FO membranes, m-phenylenediamine (MPD) and trimesoyl chloride (TMC) were used for polyamide (PA) layer formation on the substrate surface.

Moreover, it was found that the initial permeate flux decline rate for all FO membranes investigated followed the order Na+ + Ca2+ + Mg2+ > Na+ + Ca2+ > Na+ + Mg2+ > Na+, which was attributed to the particle size of SA macromolecules in the corresponding solutions.

This review focuses on the FO process's recent significant advancements in FO membranes, draw solutions, regeneration processes of draw solutions, overall energy efficiency, membrane fouling and overall performance during the long-term run, and future research directions.

This paper reviews mechanism and principle of FO membrane technology, recent advancement of the membrane (including membrane preparation and modification, and important parameters), as well as challenges and strategies for the future development of FO membranes in fruit juice concentration.

We constructed a diagram of phases and domain patterns as a function of the membrane thickness and bending angle, which allows one to readily predict the emergence of T phase and ferroelectric vortex in bent BFO membranes.

An investigation has been conducted on ZIF-8 nanoparticles surface with hydrophilicity feature to evaluate their potential for utilization in active polyamide layer of FO membranes for the first time, free from any decrease in water flux value (when hydrophobic ZIF-8 is exploited solely) and selectivity (when mSiO2 with unselective channels is employed).

Also, we thoroughly investigated how the morphological properties including surface porosity, pore size, thickness and roughness influence the performance of FO membranes.

Herein, a series of novel carbo polyetherketone (PEK-C)-based FO membranes are prepared via layer-by-layer (LBL) self-assembly by using polyethyleneimine (PEI) as the positive layer and carbon quantum dots (CQDs) as the negative layer.

We tested the separation performance of the FO membranes using DI water and 1.

Besides, the effect of UiO-PDA concentration on the overall performances (FO water flux, reverse salt flux, antifouling tendency) of the obtained UiO-PDA modified TFN-FO membranes were investigated in a cross-flow FO system.

First, the development of FO technology in terms of FO membranes, FO draw solution (DS), and FO systems is reviewed.

Performance and structure of the FO membranes under the influence of different applicator clearance gaps (ACGs) along with PF-127 wt.

Experimental results revealed that the separation performance of the TFC-FO membranes significantly improved.

To rectify this lack of knowledge, this study objectively compares draw solutes using a multi-criteria analysis (MCA) across a range of physicochemical properties (in consistent units), along with their flux performance when integrated with FO membranes.

Low-molecular-weight PEG sometimes is used as pore constrictor and pore former for developing MD membranes and support layer of FO membranes.

To improve the selectivity and permeability performance of FO membranes, the effects of MIL-53(Fe) content, casting solution temperature, coagulation bath temperature, and annealing temperature were studied.

Performance of FO membranes can be investigated by NaCl, MgCl2, Na2SO4, and sucrose as draw solutions and deionized water as feed solution.

However, the studies comparing the original TOrCs and their degradation BPs following removal or adsorption were not conducted in FO membranes.

Long-term filtration followed by chemical cleaning of the FO membranes tested resulted in 100% flux recovery with negligible irreversible fouling.

Our results confirm the possibility of fabricating novel graphene-based FO membranes by tailoring the nitrogen-bonding structure, which will significantly help develop a process for improving the scalability of membrane materials.

Although a good deal of research has been extensively investigated in the past decades, major challenges still remain as follows: (1) the novel FO membrane material properties, which significantly influence the fouling of the FO membranes, the intolerance reverse solute flux (RSF), the high concentration polarization (CP), and the low permeate flux; (2) novel draw solution preparation and utilization; (3) salinity build-up in the FO system; (4) the successful implementation of the FO process.

Taking advantage of electro-conductive graphene nanosheets, herein, a novel in-situ electro-oxidative approach has been proposed to alleviate organic fouling in FO membranes.

The fabrication methods of FO membranes are always ready for a revolution.

Forward osmosis (FO)-based water treatment and desalination processes have attracted increasing attention to address the global water crisis, but its practical application is restricted by the lack of FO membranes with high permeability and selectivity.

Assuming that FO is applied in cold regions, the temperature of the feed or draw solution may be low, thereby affecting the water productivity and fouling propensity of FO membranes.

Additionally, the rejection of the HFFO membranes using three model solutes (caffeine, niacin, and urea) were determined under both FO and reverse osmosis (RO) conditions with the same process recovery.

Here we investigated the feasibility of extracting water from four real and four synthetic anaerobically digested effluents, using FO membranes.

First, five of the most commonly used FO membranes were characterized for water permeability ( A), solute permeability ( B), and structural parameter ( S).

The fine chemical and structural properties of the TFC-FO membranes were successfully reconstructed from the depth profiles, which revealed that the sponge-like substrate with small surface pores favored the formation of a smooth and thin PA layer with a highly cross-linked inner layer, while the macroporous substrate with large surface pores facilitated the development of a rough and defective PA layer with deep formation inside substrate pores.

This study systematically investigated the critical flux behavior of FO membranes (CTA and PA-TFC) in the short-term using a stepping method (draw solution (DS) concentration stepping).

The effect of the nanofiller on the membrane surface morphology, hydrophilicity, chemical composition, and roughness of the fabricated TFN-FO membranes was systematically investigated using various characterization methods.

3 mm-thickness 60CPO-40PCFO membranes after porous La0.

Effect of the incorporation of phase-transfer catalysts (PTCs), lithium chloride (LiCl), dimethyl sulfoxide (DMSO), acetone as additives in the aqueous phase or organic phase system on the morphologies and performance of TFC-FO membranes was investigated, respectively.

A 2512 spiral element was rolled using indigenously developed TFCP-FO membranes and performance was evaluated in terms of volume reduction and back-diffusion of draw solution salts using simulated feed solution (500-ppm NaCl; 1-ppm SrCl2 and CsCl each) with 2(M) solutions of CaCl2 & (NH4)2CO3 as draw solution.

The findings provide new insights on the design and preparation of FO membranes for seawater pretreatment.

The downstream MD process was used to recover potassium sorbate draw solutes from the FO effluent and maintain the constant draw solute concentration for achieving stable water flux of FO membranes.

In short, the readers will be kept on track with the current advancement in the FO membranes to improve its performance.

Using commercial cellulose triacetate (CTA) FO membranes, the water recovery of approximately 64% was achieved and the final volume of the partially diluted dialysis concentrate was about four times the initial volume.

The effect of location of LDHs on the physicochemical property and separation performance of FO membranes was investigated in detail.