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Graphical abstract Highlights • Homogeneous formation of dynamic membrane (DM) with minimum effluent turbidity using static mixer in DMBR. • Size and place of static mixer had significant effects on the formation, stability, and filtration resistance. • The shortest formation time of DM was obtained with elevation of the static mixer size. • Membrane fouling improved with changes in static mixer place. • Role of static mixer was more prominent in reduction of operational costs and energy consumption. Abstract Homogeneous formation of a dynamic membrane (DM) on macroporous materials (such as mesh filter) in a dynamic membrane bioreactor (DMBR) is very important. In this research, an economical and efficient method was introduced for homogeneous formation of DM using a static mixer. To investigate the effectiveness of the static mixer in formation and filtration of DM, in comparison with the state without a static mixer, the size of the static mixer was examined at different aeration rates. The filtration characteristics of DMBR including formation time, stability time and fouling propensity were obtained. Further, the properties of DM including the mean particle size (M ps), soluble microbial product (SMP), average thickness and porosity of DM were measured to analyze the formed DMs in the bioreactor. The results indicated that the static mixer size (r p = −0.892) has the maximum effect on the formation time. With the crossflow velocity control, the static mixer contributed to homogeneous formation of cake layer and increased share of large particles on the mesh filter surface at the very beginning, such that the minimum formation time was achieved. Moreover, to achieve suitable conditions for the site of static mixer in the bioreactor, the effects of the place of the static mixer were examined in the best DM formation state (formation time < 5 min). It had a great impact on the stability time (r p = −0.941) and fouling propensity (r p = 0.926). Based on the obtained results, application of static mixer can contribute to saving energy and promoting the DMBR technology in wastewater treatment through shortening DM formation time and decreasing membrane fouling. [ABSTRACT FROM AUTHOR]

Employing magnetic beads for immobilized metal affinity chromatography application was studied with the approach of magnetic effects investigation. Hence, fabricated magnetic nanoparticles-carrying beads were functionalized with Ni(II)-iminodiacetic acid (IDA). BET-BJH results showed that nanoparticles affected pore sizes lower than 10 nm. Therefore, the pore blockage by protein molecules is considered as an outcome of the new pore diameter in magnetic beads. In accordance, bovine serum albumin (BSA) adsorption isotherms revealed a significant difference between magnetic and nonmagnetic beaded matrices. For nonmagnetic beads, adsorption isotherm followed Langmuir model. However, one step increase in adsorption isotherm for initial BSA concentration from 0.5 mg/ml to 0.8 mg/ml was observed on magnetic beads due to pore blockage by proteins. BSA Adsorption kinetics on beads was found to follow the assumptions of an intraparticle diffusion-controlled pseudo-second order mechanism, with higher adsorption rate constants at lower adsorbate concentrations. Furthermore, though the same IDA density on both non/magnetic beads, presence of magnetic nanoparticles reduced the required equilibrium time (up to 60 min), the saturation path of BSA adsorption breakthrough curves, dynamic binding capacity and the number of theoretical plates. It is concluded that magnetic characteristic of composite agarose adsorbent carrying Fe 3 O 4 nanoparticles affects protein’s conformation. Thus, BSA travel toward ligand is enhanced and sped up. [ABSTRACT FROM AUTHOR]

Highlights: [•] pH sensitive polyacrylic acid layer was deposited on polysulfone membrane by photopolymerization. [•] The deposited polyacrylic acid improved amoxicillin separation of nanofiltration membranes. [•] Surface charge is more effective than membranes pore size in amoxicillin separation efficiency. [•] The pH sensitivity of membranes makes charge repulsion as dominant separation mechanism. [•] Effect of pH on separation membrane efficiency was assessed by FTIR spectra. [ABSTRACT FROM AUTHOR]

Highlights: [•] To develop formation process of self-forming dynamic membrane on mesh filter. [•] To optimize imposed flux and aeration rate for self-forming dynamic membrane. [•] To evaluate efficiency of dynamic membrane bioreactor in removal of COD and TDS. [•] To investigate the preferable cleaning method for recovery of fouled mesh filter. [•] To characterize dominant chemical matter in dynamic membrane using FTIR analysis. [ABSTRACT FROM AUTHOR]

Abstract: In this study membrane fouling was studied in a novel airlift oxidation ditch membrane bioreactor (AOXMBR) working under various high organic loading rates (OLRs). The results confirmed the high performance of AOXMBR in terms of Chemical Oxygen Demand (COD) removal, even at very high OLRs. The role of the membrane barrier appeared to be significant when the COD in the supernatant was high under such conditions. In addition, the study confirmed the performance of the AOXMBR was better in comparison with the conventional activated sludge as such colloid matters cannot be retained via a simple secondary settling step. Also, on-line viability measurement of the activated sludge illustrated that the fouling increased with a decrease in the viability of the activated sludge. The results showed that the qualitative change of the activated sludge affected the fouling phenomenon. The membrane fouling dynamics analysis pointed out the relationship between cause of the membrane fouling and MBR operating conditions. Adsorption in pores appeared to be the dominant cause when any biofilm or deposit was present on the membrane surface. On the other hand at high OLR in the absence of any deficiency (oxygen deficiency, large pH variations etc.) for the microbial population the biofilm played the dominant role consequent, whereas with drastic decreases of OLRs -due to significant cell lysis – external and reversible deposits appeared as the dominant cause of membrane fouling. [Copyright &y& Elsevier]