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Polymeric ultrafiltration (UF) membranes often used in membrane bioreactor (MBR) prone to be fouled by fouling agents. Therefore, in this paper, the antifouling characteristics of polyvinylidene fluoride (PVDF) UF membranes for wastewater treatment are improved through modifying membranes by O-carboxymethyl chitosan (OCMCS)-functionalized Fe3O4 nanoparticles (OCMCSFe3O4). The modifier agent was manufactured by the adsorption of OCMCS on Fe3O4 nanoparticles, which were synthesized via co-precipitating method. Antifouling performance of membranes was assessed by permeation tests done using activated sludge suspension as a biological foulant, then the calculation of the pure water flux recovery ratio (FRR) and fouling resistance parameters. Also, to investigate the protein rejection of membranes, permeation tests were conducted by the bovine serum albumin (BSA) solution. According to the obtained results, surface hydrophilicity of the embedded membranes was improved in the low concentrations of the modified nanoparticles. However, the high quantity of the OCMCS-Fe3O4 nanoparticles (>0.1 wt. %) in the casting solution lessened membrane performance owing to the agglomeration of the nanoparticles in the polymer matrix. Although, the 1 wt. % OCMCS-Fe3O4 membrane revealed considerably higher PWF and permeation than that of the other membranes. It was because of defects and cracks in the membranes. The 0.05 wt. % OCMCS-Fe3O4/PVDF membrane exhibited the highest FRR (95.7%) and protein rejection value (48%) and the lowest irreversible fouling resistance (Rir) value (4.2%). It is concluded that the blended membranes with modified nanoparticles resulted in a high-flux ultrafiltration membrane comparable with microfiltration membrane, while its separation properties remained similar to UF membrane. [ABSTRACT FROM AUTHOR]

ABSTRACT Membrane bioreactor (MBR) as a hybrid technology for wastewater treatment is becoming more popular for wastewater treatment. However, membrane fouling has hindered the widespread application of MBRs. Many efforts have been done for fouling mitigation. In this study, high flux and antifouling microfiltration membranes with unique surface structure, high surface porosity, and permeability were prepared by electrospinning technique. Initially, the optimum thickness of electrospun polyacrylonitrile (PAN) membranes was determined and then, electrospun PAN membrane at optimum thickness were prepared by embedding para-aminobenzoate alumoxane (PABA) nanoparticles at different concentrations. The effect of PABA nanoparticles on membrane performance was investigated. To investigate the characterization of the prepared membranes Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and water contact angle measurement were employed. The flux recovery ratio results revealed that the antifouling properties of the electrospun PAN membrane were enhanced by modification. The 3 wt % electrospun PABA embedded PAN had the best permeability, hydrophilicity, and antifouling properties among the fabricated membranes and showed remarkable reusability during filtration. The results obtained suggested that the high flux and antifouling electrospun PAN membranes embedded PABA nanoparticles could be used as MBR membranes. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45738. [ABSTRACT FROM AUTHOR]

In this study, wastewater treatment was destined for generation of electricity and hygienic water by an innovative integrated microbial fuel cell – membrane separation process (MFC-MSP). An optimal antifouling nanofiltration membrane (blended with O - carboxymethyl chitosan bound Fe 3 O 4 magnetic nanoparticles (CC Fe 3 O 4 NPs)), an antifouling ultrafiltration (UF) membrane (blended with polycitrate-alumoxane nanoparticle (PC-A)) and a high efficiency proton exchange membranes were applied in MSP and MFC processes. Firstly, the performance of MFC unit under different operating conditions of reaction time (RT), mixed liquor suspended solid (MLSS) concentration and influent chemical oxygen demand (COD) concentration was investigated in terms of COD removal efficiency and power generation for synthetic dairy wastewater treatment. The experiments were modeled using response surface methodology (RSM). The results indicated that by increasing in RT and COD in concentration, the COD removal was decreased. Also, the high concentration of MLSS in anodic chamber led to high COD removal efficiency. By increasing of MLSS beyond 3000 mg/L, the maximum power generation was decreased that reveals an adverse impact of biofouling on membrane performance. After primary treatment in anodic chamber of MFC at optimum condition, the anodic chamber effluent was passed through the membranes in two modes, direct nanofiltration (NF) membrane and UF-NF membranes in series. The results indicated that the UF membrane alleviated the organic loading of NF membrane by 72% relative to the direct NF filtration. The permeation flux shows a sustain performance of the NF when is coupled with UF membrane.a. [ABSTRACT FROM AUTHOR]

In this paper, firstly sulfonated polyethersulfone (SPES) was synthesized from polyethersulfone (PES) with sulfonation by chlorosulfonic acid as a sulfonating agent dissolved in concentrated sulfuric acid. PES/SPES blend proton exchange membranes (PEMs) were prepared at four different compositions with the non-solvent induced phase separation technique as alternative materials to Nafion membrane for application in a microbial fuel cell (MFC). The prepared PEMs were characterized by FTIR spectroscopy, AFM, SEM, contact angle, water uptake and oxygen permeability. Performances of the fabricated PEMs and commercial Nafion 117 were evaluated in a dual chamber MFC for treating of wastewater and electricity generation. Maximum generated power and current of the fabricated membranes were 58.726 mWm −2 at current density of 317.111 mAm −2 , while it was 45.512 mWm −2 at 228.673 mAm −2 for Nafion 117 at the similar experimental condition. The observed properties of low biofouling, low oxygen permeability, high power generation, high COD removal and coulombic efficiency ( CE ) indicated that the SPES membrane has potential to improve significantly the productivity of MFCs. [ABSTRACT FROM AUTHOR]

Licorice processing industry produces a characteristic wastewater with a high chemical oxygen demand (COD), high turbidity, and intense color. Direct disposal of untreated licorice processing wastewater into water bodies can pose a serious risk to the human health and environment. The main objective of this study is to evaluate the performance of a novel laboratory scale continuous electrocoagulation (EC) reactor using iron (Fe) rod electrodes (anode and cathode) for treating a real licorice processing wastewater. Response surface methodology (RSM) was employed to investigate the effects of important parameters such as: current density (CD), electrolysis time, mixing intensity, and NaCl concentration for Fe rod electrodes on the removal efficiency of color, soluble COD (sCOD), and turbidity. In order to evaluate the effect of reactor design on the overall process performance, the results were compared with our previous study in which Fe plate electrodes were employed in an identical system. The process exhibited better performance in terms of turbidity removal for Fe rod electrodes with an average value of 59.35% in contrast to Fe plate electrodes (47.88%). Color and sCOD removal efficiencies of 94.6% and 90.1% were achieved, respectively for the EC system using Fe rod electrodes under optimum conditions: electrolysis time (71.8 min), CD (28 mA/cm2), mixing intensity (45 rpm). While in the EC reactor using Fe plate electrodes, the optimum (electrolysis time of 81.8 min, current density of 35 A/cm2, and mixing intensity of 45 rpm) color and sCOD removal were obtained 90.1% and 89.4%, respectively. Analysis and comparison of the data revealed that Fe rod electrodes delivered a better treatment performance than Fe plate electrodes, taking into account that the optimum electrolysis time and applied current density were considerably lower for the Fe rod electrodes. Overall, these results confirmed that the novel EC reactor using Fe rod electrodes can reduce the operating cost and be proposed as a pragmatic approach to remove high amount of color, COD, and suspended solids from licorice processing wastewater. [Display omitted] • Single-stage continuous electrocoagulation is used to treat licorice wastewater. • EC performance using Fe rod electrodes was better than that by Fe plate electrodes. • EC reactor using Fe rod electrodes exhibited a significant color removal of 94.6%. • High COD removal efficiency (%90.1) was reached at low current density (28 mA/cm2). [ABSTRACT FROM AUTHOR]

Recently, membrane bioreactors (MBRs) have received extensive attention as an innovative wastewater treatment technology. Nevertheless, membrane fouling as a serious barrier has avoided the widespread application of the MBRs. In the present study, two polyethersulfone (PES) antifouling ultrafiltration membranes entrapped by 0.1 wt. % of NH 2 functionalized multiwalled carbon nanotubes (NH 2 -MWCNTs) and of O-carboxymethyl chitosan modified Fe 3 O 4 (OCMCS- Fe 3 O 4) nanoparticles were employed in an MBR. The effect of both modified membranes on the fouling characteristics and biological performance of bioreactor was investigated. Experimental design was conducted using central composite design (CCD) of response surface methodology (RSM). The process performance of the bioreactor treating milk processing wastewater (MPW) was analyzed at different hydraulic retention times (HRTs) and mixed liquor suspended solids (MLSS). Five dependent process and operating parameters; TKN, NO 3 −, TN, TP removal efficiency and flux, were measured as response for both membranes. Independent increment of the variables gave rise to an increase in the process parameters. While, simultaneous increase in the variables led to the increase in flux. The Fe 3 O 4 −OCMCS embedded membrane indicated slightly higher flux than that of NH 2 -MWCNTs modified membrane. The optimum region was enclosed by high MLSS (≥ 12,000 mg/l) at any HRT studied. [ABSTRACT FROM AUTHOR]

• A novel continuous electrocoagulation (EC) process is designed for wastewater treatment. • EC process is evaluated for treatment of Licorice wastewater for the first time. • High color removal efficiency (90 %) from Licorice wastewater was obtained. • Minimizing energy consumption and maximizing color removal was simultaneously achieved in the integrated single EC process. The potential application of a novel continuous electrocoagulation (EC) reactor for simultaneous removal of color, chemical oxygen demand (COD), turbidity, and alkalinity from a real licorice processing wastewater was investigated. The individual and interactive effects of four key independent variables (electrolysis time, current density, NaCl concentration, and mixing intensity) was evaluated. The results suggested that color and COD removal enhances with increasing electrolysis time, current density, and mixing intensity and remains practically constant by adding higher concentrations of NaCl. The application of continuous EC process under optimal conditions, such as: electrolysis time (81.8 min), current density (350 A/m2), NaCl concentration (300 mg/L), mixing intensity (45 rpm) allows to achieve these promised removal efficiencies: 90.1 % color, 89.4 % COD, 82 % turbidity, and 73.3 % alkalinity. [ABSTRACT FROM AUTHOR]