Membranes For Wastewater Treatment Research Articles

Bacterial Cellulose Membrane for Wastewater Treatment: A Review

Bacterial Cellulose Membrane for Wastewater Treatment: A Review

Investigation of boron nitride/silver/graphene oxide nanocomposite on separation and antibacterial improvement of polyethersulfone membranes in wastewater treatment

This research introduces a practicable and straightforward procedure for improving separation performance by blending 2D nanocomposite of functionalized hexagonal boron nitride nanosheets/graphene oxide/silver (FBN-GO-Ag) polyethersulfone (PES) membrane. The objective of fabricating such membrane was to enhance the permeability, antifouling and antibacterial property, separation ability, and mechanical strength. The FBN-GO-Ag nanocomposite was synthesized, characterized, and blended at different constituent concentrations in casting solutions of the membranes. Physicochemical characterization illustrated approximately 21% and 22% increment of hydrophilicity and porosity of the modified membrane with 1 wt% FBN-GO-Ag, respectively. Meanwhile, the addition of 1 wt% FBN-GO-Ag led to an increase of 40% in permeability (80 L/m2 h bar) besides the dye removal and fouling resistance improvement compared to the unfilled membrane. Furthermore, PES membrane containing 1 wt% FBN-GO-Ag exhibited 88.9% and 77.7% rejection of reactive black 5 and reactive red 120, respectively, which is associated with the enhancement of negative surface charge of the membranes. Due to the inherent antibacterial properties of all three combined nanomaterials, the prepared nanocomposite membrane showed excellent antibacterial performance.

Fabrication of cellulose acetate membrane with advanced ultrafiltration performances and antibacterial properties by blending with HKUST-1@LCNFs

• HKUST-1@ LCNFs was fabricated through green and in-situ strategy successfully. • CA composite membranes were prepared with blending of HKUST-1@ LCNFs successfully. • CA composite membranes blended with HKUST-1@ LCNFs exhibit excellent ultrafiltration performances. • M7 has high antibacterial properties attributed to the synergistic effect of the LCNFs and HKUST-1. To expand the application of cellulose acetate (CA) membranes in wastewater treatment, the excellent ultrafiltration performance and anti-fouling properties should be achieved. Firstly, HKUST-1@ lignocellulose nanofibrils (LCNFs) was fabricated through green and in-situ strategy successfully, which combine the characteristics of the HKUST-1 and LCNFs. Then, the blended ultrafiltration membranes with different loading of HKUST-1@LCNFs (or HKUST-1, LCNFs) were prepared by the process of phase separation, which exhibit improved pore structure, hydrophilicity, and rejection rate. Excitedly, the highest pure water permeability of 207.32 L·m −2 ·h −1 and the flux recovery ratio (FRR) of 90.56% were obtained with M6 membrane (0.55 wt% HKUST-1@LCNFs), which was better than that of M2 (HKUST-1) and M3 (LCNFs). It is confirmed that HKUST-1 could inhibit the accumulation of LCNFs, making it taking advantages of its hydrophilic groups. Moreover, composite membranes have attractive antibacterial properties, and >90% of E. coli were killed by M7. This work demonstrated that CA membranes blended with HKUST-1@LCNFs possesses great potential in the wastewater treatment process.

Effect of Curing Temperature on the Properties of Latex Based Membrane for Oily Wastewater Filtration

Oily wastewater pollution has always been part of the most serious worldwide environmental disaster. Thus, the treatment of oily wastewater is notably crucial. In this work, nitrile butadiene rubber/graphene oxide (NBR/GO) membranes were fabricated by latex compounding and curing method which is comparatively brand-new technique to produce membranes for wastewater treatment. Therefore, the steps in the production need to be studied to enhance the performance of the membrane. Curing temperature is an important factor in the production of the latex-based membrane. In this paper, the effect of curing temperature in the range of 90 °C – 110 °C on the morphology, tensile properties, permeation flux, and oil rejection rate performance of the membrane was studied. The curing temperature was found to affect the surface morphology and integrity of the membranes which sequentially affects the performance of the membrane in terms of strength, permeation flux, and oil rejection rate. NBR/GO membranes cured at the temperature of 100 °C exhibit the highest flux of 491.84 L/m2.hr with an oil rejection rate of 95.44 %, with the ultimate tensile strength (UTS), elongation break (EB%), and E-Modulus (E-mod) of 34.490 MPa, 1627.11 %, and 1.309 MPa, respectively.

Dye adsorptive thin-film composite membrane with magnetite decorated sulfonated graphene oxide for efficient dye/salt mixture separation

In this study, a thin-film composite (TFC) loose nanofiltration (NF) membrane comprising a poly(piperazine-amide) (PPA) active layer was successfully fabricated by the electrospray interfacial polymerization (EIP) method. Sulfonated graphene oxide (SGO) and magnetite-decorated SGO (MGO) were synthesized and individually embedded in the polymer matrix of the substrate via a phase inversion method. The hydrophilicity, surface roughness, porosity, and pure water permeance of the prepared substrates, in which the additive existed, were found to be improved in comparison with those of the pristine substrate. The MGO nanoparticle-incorporated TFC membrane (M-MGO) exhibited high permeation of salt (96.1% for NaCl) and water permeance (44.4 ± 4.0 LMH bar−1) owing to the loose structure of the active layer. The M-MGO also exhibited the highest dye rejection (Congo red, 99.0%) owing to the presence of MGO nanoparticles with an adsorption capacity. When permeating the dye and salt mixture, M-MGO achieved the highest dye/salt selectivity in comparison with those of the other membranes. Moreover, the M-MGO achieved better antifouling properties with a high flux recovery ratio (FRR) of 99.0%, whereas the pristine membrane exhibited a low FRR of 97.6% or less. This method presents a high potential for the fabrication of novel saline wastewater treatment membranes.

Enhanced Solar Photocatalytic Reduction of Cr(VI) Using a (ZnO/CuO) Nanocomposite Grafted onto a Polyester Membrane for Wastewater Treatment.

Among chemical water pollutants, Cr(VI) is a highly toxic heavy metal; solar photocatalysis is a cost-effective method to reduce Cr(VI) to innocuous Cr(III). In this research work, an efficient and economically feasible ZnO/CuO nanocomposite was grafted onto the polyester fabric ZnO/CuO/PF through the SILAR method. Characterization by SEM, EDX, XRD, and DRS confirmed the successful grafting of highly crystalline, solar active nanoflakes of ZnO/CuO nanocomposite onto the polyester fabric. The grafting of the ZnO/CuO nanocomposite was confirmed by FTIR analysis of the ZnO/CuO/PF membrane. A solar photocatalytic reduction reaction of Cr(VI) was carried out by ZnO/CuO/PF under natural sunlight (solar flux 5–6 kW h/m2). The response surface methodology was employed to determine the interactive effect of three reaction variables: initial concentration of Cr(VI), pH, and solar irradiation time. According to UV/Vis spectrophotometry, 97% of chromium was removed from wastewater in acidic conditions after four hours of sunlight irradiation. ZnO/CuO/PF demonstrated reusability for 11 batches of wastewater under natural sunlight. Evaluation of Cr(VI) reduction was also executed by complexation of Cr(VI) and Cr(III) with 1, 5-diphenylcarbazide. The total percentage removal of Cr after solar photocatalysis was carried out by AAS of the wastewater sample. The ZnO/CuO/PF enhanced the reduction of Cr(VI) metal from wastewater remarkably.

Natural Polymer-Based Electrospun Nanofibrous Membranes for Wastewater Treatment: A Review

Natural Polymer-Based Electrospun Nanofibrous Membranes for Wastewater Treatment: A Review

Recent Progress and Challenges in Hollow Fiber Membranes for Wastewater Treatment and Resource Recovery.

Membrane processes have been extensively employed in diverse applications, specifically in industrial wastewater treatment. The technological development in membrane processes has rapidly advanced and accelerated beyond its common principle and operation. Tremendous efforts have been made in the advancement of membrane materials, fabrication method, membrane modification and integration with other technologies that can augment the existing membrane processes to another level. This review presents the recent development of hollow fiber membranes applied in wastewater treatment and resource recovery. The membrane working principles and treatment mechanism were discussed thoroughly, with the recent development of these hollow fiber membranes highlighted based on several types of membrane application. The current challenges and limitations which may hinder this technology from expanding were critically described to offer a better perspective for this technology to be adopted in various potential applications.

Ameliorated polyvinylidene fluoride based proton exchange membrane impregnated with graphene oxide, and cellulose acetate obtained from sugarcane bagasse for application in microbial fuel cell

Polyvinylidene fluoride (PVDF) based, Cellulose acetate (CA), and Graphene oxide (GO) doped membrane acts as a superior cost-effective cation exchange membrane (CEM) for the energy extraction application using microbial fuel cells (MFCs). In this study, the waste sugarcane bagasse was used to prepare CA, and the Tour method was used to prepare GO. CA and GO compositions were varied to prepare CEMs WCA-1, WCA-2, WCA-3, and WCA-4. Doping the functionalized GO material in the hydrophilic membranes enhances the contribution of conducting phase concerning its hydrophilic nature and facilitates its functional characteristics at the surface. Further, adding an adequate amount of GO improves the physicochemical properties of the membrane and its mechanical stability. Also, with the fusion of GO in the membrane, the trend for water uptake ability significantly increases. Post sulfonating the prepared membranes the enhancement in the attained proton conductivity values from 0.025 Scm-1 for WCA-1 to 0.4 Scm-1 for WCA-4 was observed, which may be attributed to the increase in the GO content in the prepared membranes. Among various prepared membranes, WCA-3 was considered for MFC application. The WCA-3 membrane outperformed several membranes for wastewater treatment and energy extraction using MFC. Columbic efficiency (CE) of 7.1%, chemical oxygen demand (COD) removal efficiency of 97.5 ± 0.8%, and power density of more than 150.22 mW m−2 were achieved without any electrode modification. Thus, the prepared low-cost novel PVDF-based, GO and CA membrane (WCA-3) elucidated its appropriateness for proliferating the efficacy of MFC and is recommended for scaling up of MFCs.

Application of sol-gel assisted ultrasound-induced atomization in the mesostructuring of nickel aluminate UF membranes

The research article presents a feasible approach to fabricate supported nickel aluminate ultrafiltration (UF) membranes. The synthesis involves an environmentally benign aqueous sol-gel method and ultrasound induced atomization technique. The process shows uniform microstructural evolution of temperature induced grain growth that transformed the surface of alumina supports into a porous metal oxide framework with porosity in the UF range. The aqueous permeability of the supported membranes was measured using the Hagen Poiseuille membrane model of the parallel open pores. The maximum value of membrane MWCO and permeability was 17 kDa and 42 LMH bar−1, respectively. The features like permeation characteristics and retention behavior indicate the potential use of supported NiAl2O4 membranes for wastewater treatment as UF membranes.

Nanocellulose Based Filtration Membrane in Industrial Waste Water Treatment: A Review.

In the field of industrial wastewater treatment, membrane separation technology, as an emerging separation technology, compared with traditional separation technology such as precipitation, adsorption, and ion exchange, has advantages in separation efficiency, low energy consumption, low cost, simple operation, and no secondary pollution. The application has been expanding in recent years, but membrane fouling and other problems have seriously restricted the development of membrane technology. Natural cellulose is one of the most abundant resources in nature. In addition, nanocellulose has characteristics of high strength and specific surface area, surface activity groups, as well as being pollution-free and renewable, giving it a very wide development prospect in many fields, including membrane separation technology. This paper reviews the current status of nanocellulose filtration membrane, combs the widespread types of nanocellulose and its derivatives, and summarizes the current application of cellulose in membrane separation. In addition, for the purpose of nanocellulose filtration membrane in wastewater treatment, nanocellulose membranes are divided into two categories according to the role in filtration membrane: the application of nanocellulose as membrane matrix material and as a modified additive in composite membrane in wastewater treatment. Finally, the advantages and disadvantages of inorganic ceramic filtrations and nanocellulose filtrations are compared, and the application trend of nanocellulose in the filtration membrane direction is summarized and discussed.

Improved two-reactor system with sulfonated membranes in wastewater treatment

The ion exchange membrane bioreactor with two-reactor system has gained attention because it has been known to be beneficial to the simultaneous removal of organic and nitrogen. However, this system has a disadvantage for accumulation of nitrate in nitrification due to low diffusivity of nitrate through a cation exchange membrane. To resolve this problem, this study proposed a unique membrane bioreactor system bounded sulfonate membrane to be applied for simultaneous removal of organic and nitrogen in wastewater. The unique membrane bioreactor system consists of two reactors called reactors A and B. The reactor A was maintained in anoxic condition while the reactor B was operated in aerobic condition during the operation period. In ammonium migration experiment, the ammonium migration rates were determined by measuring ammonium concentrations in reactor A. As a result of the measurement, the maximum mass fluxes at the initial ammonia levels of 500, 1000, 1500, and 2000 mg N/L resulted in 1.03, 2.06, 2.98, and 3.87 mg/m2• s, respectively. Those high fluxes indicated that the unique membrane bioreactor exhibited high ion diffusivity. The mass fluxes of ammonia nitrogen in this system were strongly correlated to the initial concentrations of ammonia. The nitrate produced in the reactor B by biological nitrification was effectively migrated to the reactor A, and then the migrated nitrate in the reactor A was converted to nitrogen gas by denitrifying bacteria. As a result, almost complete nitrogen removal efficiency was achieved as 99% in the batch system. Further interestingly, no severe nitrate accumulation problem was observed in reactor B in the unique membrane bioreactor, although such a problem commonly exists in the conventional cation exchange membrane bioreactor system. It is expected that this unique membrane system can be operated with low operation costs and high removal efficiencies of ammonia nitrogen.

Recent Improvement Strategies on Metal-Organic Frameworks as Adsorbent, Catalyst, and Membrane for Wastewater Treatment.

The accumulation of pollutants in water is dangerous for the environment and human lives. Some of them are considered as persistent organic pollutants (POPs) that cannot be eliminated from wastewater effluent. Thus, many researchers have devoted their efforts to improving the existing technology or providing an alternative strategy to solve this environmental problem. One of the attractive materials for this purpose are metal-organic frameworks (MOFs) due to their superior high surface area, high porosity, and the tunable features of their structures and function. This review provides an up-to-date and comprehensive description of MOFs and their crucial role as adsorbent, catalyst, and membrane in wastewater treatment. This study also highlighted several strategies to improve their capability to remove pollutants from water effluent.

Corrosion resistant ZrO2/SiC ultrafiltration membranes for wastewater treatment and operation in harsh environments

This work focused on the fabrication of a ZrO2/SiC ultrafiltration membrane by dip coating a high porous SiC support with a ZrO2 slurry prepared by ceramic processing. The membranes were sintered in different temperatures (1000−1300 °C). With the optimal temperature, it was obtained a mechanically strong, homogenous, and defect free separation layer with 45 μm of thickness and average pore size of 60 nm. A pure water permeability of 360 L.m−2 h−1 bar-1 and high retentions of humic acid, indigo dye, and hemoglobin were observed. In a pilot test with an olive oil/water emulsion, 99.91 % of oil was removed without fouling. Long-term corrosion tests at basic and acid baths did not cause change in pore size and morphology. In conclusion, the ZrO2/SiC membrane has potential to operate in harsh conditions (e.g. heavily contaminated industrial effluents or urban wastewaters) and when severe membrane cleaning and disinfection are required, such as food and pharmaceutical industries.

Fabrication and Characterization of Sulfonated Graphene Oxide-Doped Polymeric Membranes with Improved Anti-Biofouling Behavior

In this study, cellulose acetate (CA) was blended with sulfonated graphene oxide (SGO) nanomaterials to endow a nanocomposite membrane for wastewater treatment with improved hydrophilicity and anti-biofouling behavior. The phase inversion method was employed for membrane fabrication using tetrahydrofuran (THF) as the solvent. The characteristics of CA-SGO-doped membranes were investigated through thermal analysis, contact angle, SEM, FTIR, and anti-biofouling property. Results indicated that anti-biofouling property and hydrophilicity of CA-SGO nanocomposite membranes were enhanced with addition of hydrophilic SGO nanomaterials in comparison to pristine CA membrane. FTIR analysis confirmed the successful decoration of SGO groups on CA membrane surface while revealing its morphological properties through SEM analysis. Thermal analysis performed using DSC confirmed the increase in thermal stability of CA-SGO membranes with addition of SGO content than pure CA membrane.

Enabling Water Reuse by Treatment of Reverse Osmosis Concentrate: The Promise of Constructed Wetlands.

As more cities experience water stress, the use of reverse osmosis (RO) membranes for wastewater treatment and reuse will expand. The concentrated waste stream resulting from RO treatment can pose chronic ecotoxicity risks if discharged to surface waters or shallow coastal ecosystems. Most existing RO concentrate treatment technologies are cost prohibitive, but constructed wetlands hold promise as a viable multibenefit solution because they have the potential to provide simultaneous treatment of nutrients, metals, and trace organic contaminants at a relatively low cost. They also are popular with the public. A handful of water-stressed cities have already begun experimenting with constructed wetlands for RO concentrate treatment. However, further research is needed to reduce the land area needed for treatment and increase the reliability of constructed wetland systems.

Thin-Film Composite Polyamide Membranes with In Situ Attached Ag Nanoparticles for Fouling-Mitigated Wastewater Treatment

As an ideal membrane for wastewater treatment, desirable separation performance, and fouling resistance are both requisite. Herein we directly in situ attached Ag based nanoparticles on the surface of thin-film composite polyamide (TFC PA) membranes by using benzenediamine (BDA) derivatives with acid functional groups as one aqueous monomer mixed with m-phenylenediamine (MPD) for interfacial polymerization (IP). The acid functional groups in BDA derivatives incorporated in the PA layer facilitated the in situ metallization or mineralization without grafting additional “bridge” linkers. Various characterization techniques were employed to elucidate the modification mechanism. The effects of molecular structures of BDA derivatives on the surface properties, separation performance, and antifouling capacity of resulting membranes were also systematically investigated. Compared with the pristine TFC membrane, the modified membranes exhibited the 85.83% water flux enhancement and 65.25% lower reverse salt flux overcoming the permeability-selectivity trade-off. Moreover, the total Ag loading of modified membranes increases by 8–14 times as compared to that of the pristine one, thereby the enhanced antibacterial and antifouling capacities in wastewater treatment.

Development of a Polymeric Carbon Nanocomposite Hollow-Fiber Membrane for Wastewater Treatment.

This study investigated experimental parameters to fabricate polymeric carbon nanocomposite hollow-fiber membranes with graphene oxide and multi-walled carbon nanotubes. This case was different from that of flat-sheet type membranes in that the characteristics of the hollow-fiber type membranes were affected by the structure of the spinneret, the flow rate of the injected polymer and draw solution, and the mixing ratio. The membranes were characterized in terms of mechanical strength, porosity, hydrophilicity, and permeate flux using different solutions. The results reveal a mechanical strength of the carbon nanocomposite hollow-fiber membranes that is about 47.8% higher than that of hollow-fiber membranes without carbon nanomaterials. The porosity and surface hydrophilicity changed to produce more applicable membranes for water and wastewater treatment. As for the permeate flux, the nanocomposite membrane with graphene oxide showed a higher flux compared to the multi-walled carbon nanotubes membrane, which could be influenced by structural effects of the carbon materials.

Prospects of Synthesized Magnetic TiO2-Based Membranes for Wastewater Treatment: A Review.

Global accessibility to clean water has stressed the need to develop advanced technologies for the removal of toxic organic and inorganic pollutants and pathogens from wastewater to meet stringent discharge water quality limits. Conventionally, the high separation efficiencies, relative low costs, small footprint, and ease of operation associated with integrated photocatalytic-membrane (IPM) technologies are gaining an all-inclusive attention. Conversely, photocatalysis and membrane technologies face some degree of setbacks, which limit their worldwide application in wastewater settings for the treatment of emerging contaminants. Therefore, this review elucidated titanium dioxide (TiO2), based on its unique properties (low cost, non-toxicity, biocompatibility, and high chemical stability), to have great potential in engineering photocatalytic-based membranes for reclamation of wastewater for re-use. The environmental pathway of TiO2 nanoparticles, membranes and configuration types, modification process, characteristics, and applications of IPMs in water settings are discussed. Future research and prospects of magnetized TiO2-based membrane technology is highlighted as a viable water purification technology to mitigate fouling in the membrane process and photocatalyst recoverability. In addition, exploring life cycle assessment research would also aid in utilizing the concept and pressing for large-scale application of this technology.

Simultaneous exfoliation and functionalization of hexagonal boron nitride in the aqueous phase for the synthesis of high-performance wastewater treatment membrane

A highly permselective membrane is needed for environmental applications due to current industrialization and environmental constraints. However, membrane fouling and firmness problems are encountered during operation in harsh working environments. Hexagonal boron nitride is an encouraging material due to its solidity under various working conditions, but exfoliation using environmentally friendly techniques is challenging. In this study, aqueous-phase exfoliation using tannic acid was demonstrated to be an easy, novel, and green method for preparing functionalized two-dimensional hexagonal boron nitride nanosheets. Microscopic and spectroscopic techniques were used to characterize the exfoliated nanosheets and the synthesized membrane. Tannic acid is adsorbed on the hexagonal boron nitride surface and gradually exfoliates the hexagonal boron nitride to release a few layers of functionalized boron nitride nanosheets; it behaves as a green surfactant by weakening the interlayer interactions. Ultimately, the functionalized exfoliated nanosheets are used to prepare a membrane for environmental applications. Fascinatingly, the prepared membrane is exceedingly stable in water and organic solvents and manifests adequate efficiency in transporting solvents with excellent screening of solutes and long-term antifouling performance. The synthesized membrane's rapid transport of solvents and ample separation efficiency of solutes may be due to the robust nanochannel and thin laminar networks of the nanosheets, which endow the membrane with favorable properties for separation and decontamination developments.