Removal Of Bovine Serum Albumin Research Articles

Comparison of aluminum formate and traditional aluminum coagulants in structure, hydrolysates, coagulation behavior, and its corrosion resistance advantage

Aluminum formate (AF) has been considered as a superior coagulant that can decompose under the UV light without causing equipment corrosion during water treatment. The main components of the aluminum formate coagulant are aluminum formate (C3H3AlO6), aluminum formate hydrate (C3H3AlO6·3H2O), and aluminum hydrogen formate (C3H3AlO6·2H2O2). Analysis of the hydrolyzed products revealed that the content of added formic acid during the synthesis of aluminum formate is a crucial factor influencing its coagulation effectiveness. Increasing the HCOOH/Al ratio from 1.5 to 4.0 resulted in smaller mass-to-charge ratio (m/z) and higher positive charge for AF hydrolysates, with fewer undetected aluminum species present. Hydrolysates of AF 1.5 exhibited similar characteristics to those of aluminum polychloride, while AF 3.0 demonstrated optimal glucan removal efficiency (>55 %) through physical absorption rather than chemical bond bridging as the primary coagulation mechanism. The jar test results for bovine serum albumin (BSA) coagulation removal indicated a decrease in removal efficiency as the HCOOH/Al molar ratio increased from 1.5 to 4.0, accompanied by a decrease in pH conditions from 6.35 to 7.27. The highest BSA removal efficiency (58 %) was achieved using AF 1.5 at pH 6.35, suggesting that BSA molecules were captured by aluminum formate through chemical bonds such as NO-Al-, Al2(SO4)3, unlike the physical absorption effect observed in glucan coagulation process. Furthermore, it should be noted that compared to traditional aluminum salt coagulants, aluminum formate exhibits excellent pipeline corrosion resistance properties.

Surface decoration of polyethylene terephthalate (PET) waste bottle-derived ultrafiltration membrane for enhanced lead ion removal and antifouling properties

PET waste bottle can be potentially used to create eco-friendly ultrafiltration (UF) membranes for water and wastewater treatment. The surface modification and functionalization of PET UF membrane offer opportunities to further heighten the performance of the membrane. In this study, phase inversion technique was used to fabricate PET UF membranes and PET/graphene oxide (GO) nanocomposite membranes through a facile GO suspension coating approach. The GO nanosheets were deposited on the PET UF membrane as a wavy and wrinkly layer. Using lead (Pb) ions and bovine serum albumin (BSA) feed solutions, the filtration performances of the neat PET and GO-PET membranes were evaluated. It was observed that, the Pb ions and BSA removal efficiencies were greatly enhanced by the surface decorated GO. Compared to neat PET, the 0.5GO-PET membrane exhibited improved flux performance by 188% and 61% for the removal of Pb ions and BSA, respectively. A high Pb ion removal of 100% and a BSA rejection of 97% were achieved by 0.5GO-PET membrane. The lower fouling tendency of 0.5GO-PET membrane during long-term filtration was attributed to the increased surface hydrophilicity and smoothness upon the deposition of GO layer. This study demonstrates a sustainable solution for efficient water treatment and heavy metal removal.

Preparation and performance evaluation of Polycarbonate/Polysulfone blend membranes for removal of Bovine serum albumin from water

ABSTRACT Blend membranes of polycarbonate and polysulfone were studied for removal of bovine serum albumin (BSA) from water. The membranes were prepared by blending (1–10) wt.% of polysulfone with polycarbonate and then non-solvent induced phase separation (NIPS) of blend solutions. Structural analysis, thermal and tensile properties, water uptake, porosity, water contact angle, and morphological studies were conducted. Water treatment performance of membranes were tested in a crossflow system in terms of pure water flux, rejection, and fouling. BSA rejection value was improved from 85.65% to 92.88% for polycarbonate membrane in the presence of 10 wt.% polysulfone.

Permeable and antifouling PSf‐Cys‐CuO ultrafiltration membrane for separation of biological macromolecules proteins

AbstractMembrane technology has been extensively applied for protein separation. A membrane with reliable filtration performance and high removal efficiency is required. In this study, an ultrafiltration (UF) membrane was fabricated by dry‐wet phase inversion to incorporate copper oxide nanoparticles (CuO NPs) with a different ratio of L‐cysteine (Cys) in polysulfone (PSf). The characterization of the membrane involves using scanning electron microscopy (SEM), water contact angle, water content, pore size, and porosity analysis. The membrane performance evaluation includes flux permeation and bovine serum albumin (BSA) removal as a protein foulant. The membrane antifouling feature was examined by dynamic filtration of BSA. It was found that the Cys to CuO NPs ratio of 1.7:1 gives an optimal value on flux permeation and protein removal. The membrane exhibited high removal of BSA with 96.3%, and optimum water flux was achieved at 173.3 L/m2h, respectively. The highest permeability of aqueous BSA permeate at 500 ppm was about 111 L/m2h and 82.5 L/m2h for 1000 ppm. The enhancement of PSf‐Cys‐CuO membrane performance could be due to its lower contact angle (68.7°), high porosity (68%), and ideal pore size (46 nm) as well as showing good morphological structure. Most significantly, the inclusion of Cys improves antifouling capabilities. The membrane showed a lower chance of fouling based on the evaluation of the relative flux reduction and flux recovery ratio. Hence, the availability of Cys has a better impact on the polymer‐based membrane and seems promising for protein separation applications.

Antibacterial and Antifouling Properties of Ag‐ and Cu‐Decorated Thin Film Composite Polyamide Reverse Osmosis Membranes

AbstractIn this work, silver and copper particles of different nanoparticle precursor concentrations were decorated on the surface of thin film composite polyamide (TFC‐PA) reverse osmosis (RO) membranes by in situ method. The modified membranes were characterized by different techniques including Field emission scanning electron microscopy (FE‐SEM), X‐ray Absorption Spectroscopy (XAS), and attenuated total reflection – Fourier transforms infrared spectroscopy (ATR‐FTIR), water contact angle (WCA), and antibacterial capacity. After that, the membrane performance was compared through normalized flux and the possibility of the removal of bovine serum albumin (BSA) protein; the anti‐fouling and anti‐biofouling properties were also compared through the maintained flux ratios (%) after 5‐hour filtration. The used organic foulants were BSA protein and humic acid (HA) solutions. The results showed that, compared to the flux of the base, the flux of AgNPs‐decorated membrane can improve the separation ability up to 24% while that of CuNPs‐decorated membrane was 14%. The anti‐fouling property of decorated membranes was significantly increased compared to that of the base (from 64% for the base to over 77% for decorated membranes). Especially, the anti‐biofouling property of nanoparticles decorated membranes was also increased because of the higher maintained flux ratios (from 50% for the base to over 75% for decorated membranes). It indicates that this method can be applied to produce reverse osmosis (RO) membranes for reclamation wastewater with a high content of organic matter.

Responsive switchable wettability membrane prepared via hydrogel coating and its performance recovery evaluation via membrane distillation

Excessive fouling and wetting phenomenon during long term membrane distillation (MD) cause membrane degradation and lead to consistent need for membrane replacement. Hence, effective cleaning of fouled membrane is imperative to recover its performance without compromising structural integrity. In this work, poly(N-isopropylacrylamide) (PNIPAM) hydrogel was coated on the hydrophobic PTFE support via spray coating (SC) method to fabricate membrane with switchable wettability for membrane cleaning. By using bovine serum albumin (BSA) and sodium alginate (SA) as model foulants, the antifouling property of hydrogel coated membrane (HCM) was evaluated. Furthermore, chemical-less thermal cleaning on the fouled HCM membrane using water at different temperature was tested to determine its water flux recovery. The interchanging hydrophilic/hydrophobic properties of PNIPAM around its LCST facilitated the foulants removal. It was found that the PNIPAM layer could fully coat the membrane and the flux of HCM performance can be recovered by up to 59.58% and 73.66% after subjecting to fouling by bovine serum albumin (BSA) and sodium alginate (SA). Surface free energy study also showed that hydrogel incorporation could ease the removal of BSA and SA upon water cleaning and does not contribute to wetting phenomenon.

Efficient removal of bovine serum albumin from water by cellulose acetate membranes modified with clay and titania nano particles.

Modified cellulose acetate membranes with bentonite clay (CA/bent) and TiO2 nanoparticles (CA/TiO2) using the phase inversion method are successfully prepared and characterized. These Membranes are favored due to their high salt rejection properties and recyclability. The IR and EDX spectral data indicate the formation of modified membranes. The Scan Electron Microscope micrographs show that the modified membranes have smaller particle sizes with higher porosity than the neat membrane. The average pore diameter is 0.31µm for neat cellulose acetate membrane (CA) and decreases to 0.1µm for CA/0.05bent. All modified membranes exhibit tensile strengths and elongation percentages more than the neat membrane. The higher tensile strength and the maximum elongation% are 15.3N/cm2 and 11.78%, respectively, for CA/0.05bent. The thermogravimetric analysis of modified membranes shows higher thermal stability than the neat membrane. The modified membranes exhibit enhanced wettability and hydrophilicity compared with cellulose acetate, by measuring the contact angle which decreases from 60° (CA) to 40° (CA/0.1bent). The ultrafiltration tests indicated that the CA/bent and CA/TiO2 are better than CA. The most efficient nanocomposite membrane is CA/0.05bent with 100% removal of (BSA) from industrial water with a flux equal to 9.5mL/min under an applied pressure of 20bar. Thus, this study introduces a novel ultrafiltration membrane (CA/0.05bent) that can be used effectively to completely remove bovine serum albumin from contaminated water.

Highly Permeable MoS2 Nanosheet Porous Membrane for Organic Matter Removal.

MoS2 nanosheets were synthesized by a bottom-up green chemical process where l-cysteine was used as a sulfur precursor. With specific concentrations, molar ratio of reactants, and pre-mixing conditions, MoS2 nanosheets of 200–300 nm in size and 4.2 nm in average thickness were successfully obtained. Porous membranes were then prepared by depositing the MoS2 nanosheet suspension on a 0.1 μm pore size poly(vinylidene difluoride) membrane filter in a multiple batch procedure. The membrane deposited with 12 batches of MoS2 nanosheets achieved 93.78% removal of bovine serum albumin. Acid red removal of 95.65% was also achieved after the second filtration pass. The porous MoS2 nanosheet membrane also demonstrated a high water flux of 182 ± 2.0 L/(m2 h). This result overcame the trade-off between selectivity and permeability faced by polymeric ultrafiltration membranes. The MoS2 nanosheets as building blocks formed not only intersheet slit pores with a narrow half-width to restrict the passage of organic molecules but also macro-channels allowing easy passage of water. The assembled MoS2 nanosheet membrane delivered promising separation of protein molecules and a high flux, attributing to its porous nanostructure, and could be a potential membrane for various water applications.

Asymmetrical ultrafiltration membranes based on polylactic acid for the removal of organic substances from wastewater

The continued use of non-biodegradable polymeric-based membranes for water purification has led to an unsustainable accumulation of waste at disposal, resulting in various environmental problems. In this study, eco-friendly asymmetric ultrafiltration (UF) membranes were fabricated from polylactic acid (PLA) with different polymer concentrations using the phase inversion method. The fabricated membranes were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), contact angle, porosity, and pore size analysis. Permeate flux and organic matter (bovine serum albumin (BSA)) rejection were evaluated using synthetic wastewater. The anti-fouling properties of PLA membranes were investigated through static adsorption and dynamic filtration of BSA. Furthermore, the performance of the best performing PLA membrane was evaluated via chemical oxygen demand (COD) rejection as well as membrane fouling using raw municipal wastewater obtained from a local wastewater treatment plant (WWTP) in Abu Dhabi (UAE). The results indicated that increasing the PLA concentration to 20 wt% improved BSA removal from synthetic and raw wastewaters by up to 92 and 89%, respectively, in addition to improving the membrane anti-fouling property. The post-filtration and after cleaning FT-IR spectra revealed high antifouling property with no detection of BSA peaks, SEM images confirmed the reduction in membrane's pore size as PLA concentration increased, resulting in enhancing the antifouling properties of the membranes. In conclusion, this study demonstrated that PLA-UF membranes could be a viable eco-friendly alternative to traditional crude oil-derived membranes.

Removal of bovine serum albumin and methylene blue using a hybrid membrane of single walled carbon nanotube-banana peel protein: Fabrication and characterization

An environmentally friendly, facile and nondestructive method was developed for the fabrication of nano-bio hybrid membranes. Single-walled carbon nanotubes (SWNTs) were self-assembled via a one-step fabrication procedure using a protein extract from banana peel waste as a biological glue. A large fraction of the protein extract consisted of aliphatic and polar/amphiphilic residues. The hydrophobic functional groups of the protein extract were probably responsible for the binding of the extract to the SWNTs, with this binding involving π - π stacking and hydrophobic interactions, while hydrophilic groups of the protein extract possibly provided an ionic environment for the SWNT-protein hybrids. These hybrids were easily transplanted onto membrane support for use in water treatment. Due to the non-destructive assembly of SWNTs and proteins extracted from the banana peel, the hybrid membranes maintained the electrical conductivity of the SWNTs and hydrophilicity of the protein extract. Water contact angle and porosity values of the hybrid membrane were found to depend on the SWNT and protein contents. Specifically, the porosity and water permeate flux increased with increasing protein content. The SWNT-protein hybrid membrane was successfully used to reject the cationic dye methylene blue and the protein bovine serum albumin, results demonstrating the filtration capability of this membrane. • Self-assembly of SWNTs with the assistance of a protein extract from banana peels. • Applicability of SWNT-protein hybrids for membrane fabrication via a one-step process. • Display of electrical conductivity and hydrophilicity by SWNT-protein hybrid membranes. • Effective removal of contaminants from water by SWNT-protein hybrid membranes.

Insights into the coupling pre-ozonation with coagulation pre-treatment for mitigating biopolymer fouling of reverse osmosis membrane: Role of Ca2+

Although extensive efforts have been devoted to mitigate reverse osmosis (RO) membrane fouling by ozonation + coagulation (O + C) pre-treatment, it still remained unclear that whether pre-ozonation benefited the coagulation to remove organics and reduce membrane fouling in the presence of calcium ion (Ca2+). In this study, coagulation and O + C pre-treatments were used to alleviate reverse osmosis (RO) membrane fouling by biopolymer with different concentrations of Ca2+. Bovine serum albumin (BSA) and sodium alginate (SA) were chosen to represent protein and polysaccharides in biopolymer, respectively. The physicochemical properties of BSA and SA (e.g., dissolved organic carbon (DOC) concentration, particle size and zeta potential), the residual Ca2+ and Fe3+ (coagulant) concentration, and membrane autopsy were analyzed to reveal the fouling mechanism. The results exhibited that the effect of ozonation on coagulation for RO membrane fouling mitigation strongly depended on the biopolymer species and Ca2+ concentration. Ozonation promoted coagulation to alleviate BSA fouling at low Ca2+ concentration of 0.5 mM, but it was contrary for SA. The elevated Ca2+ concentration within a certain range (i.e., from 0.5 to 2.0 mM) was beneficial for O + C pre-treatment to mitigate membrane fouling by BSA and SA, thus ozonation acted as a coagulation aid to lessen BSA and SA fouling at higher concentration of Ca2+. The positive impact of Ca2+ on fouling control by O+C pre-treatment was resulted from the synergistic impact of the increase in DOC removal, the decrease in hydrophobicity, the residual Ca2+ and Fe3+ (coagulant) concentrations according to the principal component analysis (PCA). However, when Ca2+ concentration further increased to 4.0 mM, BSA fouling mitigation by O + C pre-treatment deteriorated due to the negligible promoted BSA removal efficiency and sharply increased residual Ca2+ concentration. This study got new insights into the effect of O + C pre-treatment on biopolymer fouling alleviation in the presence of Ca2+, which might guide researchers to effectively control RO membrane fouling during wastewater reclamation.

Enhanced membrane fouling control and trace organic compounds removal during microfiltration by coupling coagulation and adsorption in an electric field

Coupling electric field, coagulation, and powdered activated carbon (PAC) adsorption in the microfiltration (MF) process was an effective strategy for membrane fouling alleviation and trace organic compounds (TrOCs) elimination. In the electric field, the surface charges of bovine serum albumin (BSA) molecules and kaolin particles distributed along the direction of the electric field and formed electric dipoles, which lowered electrostatic repulsion between BSA-BSA, BSA-kaolin, and kaolin-kaolin, resulting in enhanced particle aggregation and turbidity reduction. Electrophoretic migration also strengthened the interaction between particles and polyaluminum chloride (PACl). Protein removal showed a significant linear correlation with the transmembrane pressure (TMP), and the slope variation of the fitting curves reflected the role of the electric field in the BSA removal and membrane fouling control. Under the synergistic function of electric field, coagulation, and PAC adsorption, the MF system achieved an 80.7% reduction on membrane fouling, an average BSA removal of 76.4%, and TrOCs elimination of 65.3%–81.7%. Electrochemical oxidation was the main contributor to the TrOCs removal when 2.5 V voltage was applied, and could also prolong the service life of PAC.

Effects of different Ca2+ behavior patterns in the electric field on membrane fouling formation and removal of trace organic compounds

The effects of Ca2+ on membrane fouling and trace organic compounds (TrOCs) removal in an electric field-assisted microfiltration system were investigated in the presence of Na+ alone for comparison. In the electric field, negatively charged bovine serum albumin (BSA) migrated towards the anode far away from the membrane surface, resulting in a 42.9% transmembrane pressure (TMP) reduction in the presence of Na+ at 1.5 V. In contrast, because of the stronger charge shielding of Ca2+, the electrophoretic migration of BSA was limited and led to a neglectable effect of the electric field (1.5 V) on membrane fouling. However, under 3 V applied voltage, the synergistic effects of electrochemical oxidation and bridging interaction between Ca2+ and BSA promoted the formation of denser settleable flocs and a thinner porous cake layer, which alleviated membrane fouling with a 64.5% decrease in TMP and nearly 100% BSA removal. The TrOCs elimination increased with voltage and reached 29.4%–80.4% at 3 V. The electric field could prolong the contact between TrOCs and strong oxidants generated on the anode, which enhanced the TrOCs removal. However, a stronger charge shielding ability of Ca2+ weakened the electric field force and thus lowered the TrOCs removal.

Corn derivative mesoporous carbon microspheres supported hydrophilic polydopamine for development of new membrane: Water treatment containing bovine serum albumin

A new mixed matrix membrane (MMM) was prepared by incorporating biological mesoporous carbon microspheres (mCMSs) from corn starch polysaccharide-supported hydrophilic polydopamine (PDA), as a mesoporous and large-surface area filler, selective modifier, and pore-forming agent, into polyvinylidene fluoride (PVDF) matrix in presence of polyethylene glycol (PEG) as a hydrophilic agent. The structural parameters of the prepared membranes were characterized via FE-SEM, BET/BJH, XRD, FT-IR, and AFM analyses, sorption experiments, water permeability assessments, porosimetry tests, flux recovery ratio (FRR) evaluations, and contact angle measurements, with the so-called central composite design (CCD) been successfully applied for optimization and investigation of the effects of the operational parameters. The results were then applied to treat double-distilled water containing bovine serum albumin (BSA) utilizing a cross-module set-up. Based on the findings, the content of the mCMS-PDA in the PVDF matrix significantly affected the contact angle, pure water flux (PWF), FRR, and BSA removal. In this respect, the PWF of the PVDF-PEG-mCMS-PDA increased from 10.25 to 27.78 L/m2 h with increasing the mCMS-PDA content, with the peak FRR (93.84%) of the PVDF-PEG-mCMS-PDA seen at maximum surface hydrophilicity of the membrane.

Tight ultrafiltration: Layer deposition of Trimesoyl chloride/β-Cyclodextrin onto Polysulfone/Poly (styrene-co-maleic anhydride) membrane for water treatment

Polysulfone–Styrene Maleic Anhydride (PSF/SMA) ultrafiltration (UF) membranes were prepared by the thermally induced phase separation (TIPS) method. The morphology of the UF membranes was fine tuned by varying the concentration of SMA. The surface of the membranes was then modified by dip-coating with β-cyclodextrin (β–CD) and Trimesoyl Chloride (TMC) to form tight UF membranes. The effects of β–CD on the separation performance, structure, and morphology of the flat sheet PSF/SMA membrane were examined. The tight UF membranes were characterized and then tested for the removal of Bovine Serum Albumin (BSA) and Congo red from water. The thickness was varied by increasing the concentration of β-CD. When increasing the concentration of β-CD from 2.0 % w/v to 8.0 % w/v, the thickness of the top layer increased from 8 μm to 18 μm, respectively. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and X-Ray Photoelectron Spectroscopy (XPS) were used to confirm the successful deposition of the TMC and β-CD at the surface of the membrane. It was also established through Atomic Force Microscopy (AFM) that the roughness of membranes increases with an increase in β-CD concentration. The contact angle of the tight UF PSF/SMA blend membranes declined from 79.8° to 55.9° at the addition of β-CD implying that the hydrophilicity of the membranes improved. The lowest pure water flux of 40 Lm−2 h-1 was achieved by the membrane coated with 8.0 % w/v of β-CD. However, the highest pure water flux of 127 Lm−2hr−1 was observed on the uncoated PSF/SMA UF membrane at 3 % wt/wt SMA. The highest BSA rejection (94 %) was recorded from PSF/SMA with a coating layer containing 8 % wt/v of β-CD concentration. Furthermore, the maximum Congo red dye rejection (96 %) was achieved by the tight UF membrane when β-CD concentration was 8 wt/v and the SMA was 3 % wt/wt.

Liberibacter crescens biofilm formation in vitro: establishment of a model system for pathogenic \u2018Candidatus Liberibacter spp.\u2019

The Liberibacter genus comprises insect endosymbiont bacterial species that cause destructive plant diseases, including Huanglongbing in citrus and zebra chip in potato. To date, pathogenic ‘Candidatus Liberibacter spp.’ (CLs) remain uncultured, therefore the plant-associated Liberibacter crescens (Lcr), only cultured species of the genus, has been used as a biological model for in vitro studies. Biofilm formation by CLs has been observed on the outer midgut surface of insect vectors, but not in planta. However, the role of biofilm formation in the life cycle of these pathogens remains unclear. Here, a model system for studying CLs biofilms was developed using Lcr. By culture media modifications, bovine serum albumin (BSA) was identified as blocking initial cell-surface adhesion. Removal of BSA allowed for the first time observation of Lcr biofilms. After media optimization for biofilm formation, we demonstrated that Lcr attaches to surfaces, and form cell aggregates embedded in a polysaccharide matrix both in batch cultures and under flow conditions in microfluidic chambers. Biofilm structures may represent excellent adaptive advantages for CLs during insect vector colonization helping with host retention, immune system evasion, and transmission. Future studies using the Lcr model established here will help in the understanding of the biology of CLs.

A microplate incubation method for assessing egg quality of the barfin flounder: effects of well size and rearing medium on larval viability

In microplate incubation, fish eggs and larvae are individually reared in small wells. This technique is useful for assessing hatchability, larval survival, and larval abnormality. Nevertheless, the optimal well size (water volume) and rearing media required to ensure full larval viability vary among species. In this study, we examined the effects of well size and rearing medium on hatchability and larval viability of the barfin flounder Verasper moseri and attempted to optimize the incubation conditions for this species. Fertilized eggs were individually stocked in 24-, 48-, and 96-well plates filled with 2, 1, and 0.25 mL seawater containing antibiotics (penicillin G potassium and streptomycin sulfate) and bovine serum albumin (BSA), both of which are required in the rearing media for other species. The eggs were incubated without replacing the medium. Hatch timing and rate were similar in all plate types. Completion of yolk resorption was delayed only in the 96-well plates. In the 24- and 48-well plates, the larvae survived more than 2 weeks after complete yolk resorption until they were starved to death. When the antibiotics were removed from the media, larval mortality increased. In contrast, removal of BSA from the media did not increase yolk sac stage larval mortality for barfin flounder unlike that reported for other species. These results indicate that the use of 24- and 48-well microplates filled with seawater containing antibiotics is optimal for barfin flounder larval viability beyond the completion of yolk resorption.

The antifouling performance of an ultrafiltration membrane with pre-deposited carbon nanofiber layers for water treatment

In order to improve the performance of the ultrafiltration (UF) membrane process in drinking water treatment, in terms of permeate flux and natural organic matter (NOM) removal, a new form of carbon nanofiber (CNF) layer derived from bacterial cellulose (BC) was prepared and applied as a pre-deposited coating on the UF membrane surface. Using bench-scale, dead-end filtration tests, both CNF and CNF modified by ethanol treatment (M-CNF), were evaluated for the treatment of two model NOM solutions, namely bovine serum albumin (BSA) and sodium alginate (SA). The results showed that both types of coating were effective in mitigating membrane fouling (lower flux decline), with the mitigation increasing with the coating quantity, and also enhanced the removal of BSA and SA. In particular, the M-CNF layer at the greater loading (24 g/m2) was able to reduce membrane fouling to a very substantial degree and achieve > 90% removal of BSA and SA. Characterization of the CNF and M-CNF layers showed significant differences in their morphological and structural properties which may explain the observed differences in their ability to reduce membrane fouling; protection of the UF membrane by the carbon nanofiber layers may be attributed to both physical separation and surface adsorption of the NOM biopolymers.

Nanosized aptameric cavities imprinted on the surface of magnetic nanoparticles for high-throughput protein recognition.

The authors introduce a new kind of surface artificial biomimetic receptor, referred to as aptameric imprinted polymer (AIP), for separation of biological macromolecules. Highly dispersed magnetic nanoparticles (MNPs) were coated with silica and then functionalized with methacrylate groups via silane chemistry. The aptamer was covalently immobilized on the surface of nanoparticles via a "thiol-ene" click reaction. Once the target analyte (bovine serum albumin; BSA) has bound to the aptamer, a polymer is created by 2-dimensional copolymerization of short-length poly(ethylene glycol) and (3-aminopropyl)triethoxysilane. Following removal of BSA from the polymer, the AIP-MNPs presented here can selectively capture BSA with a specific absorbance (κ) as high as 65. When using this AIP, the recovery of BSA from spiked real biological samples is >97%, and the adsorption capacity is as high as 146mgg-1. In our perception, this method has a wide scope in that it may be applied to the specific extraction of numerous other biomolecules. Graphical abstract Schematic presentation of the AIP (aptamer-imprinted polymer) introduced here. The surface of silica coated magnetic nanoparticles is modified with a polymer that is covalently modified with an aptamer against bovine serum albumin (BSA).

Fouling control mechanisms in filtrating natural organic matters by electro-enhanced carbon nanotubes hollow fiber membranes

Membrane fouling is a ubiquitous and costly problem for membrane bioreactor (MBR) that usually deteriorated membrane performance. Applied voltage on membrane is an important strategies mitigating the fouling. To evaluate antifouling mechanisms of electro-enhanced carbon nanotubes hollow-fiber membranes (CNTs-HFMs), the removal of bovine serum albumin (BSA), sodium alginate (SA) and supernatant of anaerobic bioreactor (SAB) were performed. The results showed that the optimal applied voltage (− 1.2 V) could effectively reduce membrane fouling from excluding the negative pollutants far away from the membrane surface, offering an impediment on forming gel layer and controlling the formation of high-molecular-weight pollutants. The effluent COD removal efficiencies by filtrating BSA (92.1%), SA (87.3%) and SAB (56.8%) at − 1.2 V were 3.3, 1.4 and 1.5 times higher than that of membrane filtration alone. Then, a short-term experiment (30 days) was performed, where CNTs-HFMs served dual function as the cathode and filtration function in an electro-enhanced anaerobic bioreactor (AnEMBR). The results presented that a low transmembrane pressure of 0.35 bar was obtained compared to the control reactor (0.60 bar), implying that applied voltage on CNTs-HFMs contributed to alleviate membrane fouling. This work implied that electrochemical control might provide a promising avenue to mitigate membrane fouling in MBR.