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Membrane science and technology is growing rapidly worldwide and continues to play an increasingly important role in diverse fields by offering high separation efficiency with low energy consumption. Membranes have also shown great promise for “green” separation. A majority of the investigations in the field are devoted to the membrane fabrication and modification with the ultimate goals of enhancing the properties and separation performance of membranes. However, less attention has been paid to membrane life cycle management, particularly at the end of service. This is becoming very important, especially taking into account the trends toward sustainable development and carbon neutrality. On the contrary, this can be a great opportunity considering the large variety of membrane processes, especially in terms of the size and capacity of plants in operation. This work aims to highlight the prominent aspects that govern membrane life cycle management with special attention to life cycle assessment (LCA). While fabrication, application, and recycling are the three key aspects of LCA, we focus here on membrane (module) recycling at the end of life by elucidating the relevant aspects, potential criteria, and strategies that effectively contribute to the achievement of green development and sustainability goals.

With production of over 6 million tonnes a year of sesame, its capsules are considered to be an unutilized waste. In this study, extraction of pectin from this novel source was optimized using a green method, and the functional and physiochemical characteristics of the resultant pectin were compared to commercial pectin.In this study, the sesame capsule pectin (SCP) extraction conditions were optimized to reach maximum yield, and the results showed that the maximum pectin extraction yield (138 g kgSesame capsule pectin, when compared to commercial pectin, demonstrated better functional properties in terms of emulsifying properties, oil holding capacity, foaming capacity and antioxidant activity. SCP showed similar properties in comparison to its commercial counterpart, which suggests that it could well be considered as a new and suitable source for pectin extraction. © 2022 Society of Chemical Industry.

This research aimed to valorize almond hulls based on a zero-waste strategy towards sustainable agricultural developments for the recovery and production of valuable compounds. For this purpose, the potential to produce four products, including pectin (AHP), phenolic compounds (AHPC), pullulan (PUL), and single-cell protein (SCP), was examined. The acidic extraction factors were optimized using a Box-Behnken design for the simultaneous extraction of AHP and AHPC, and the obtained results showed that the maximum AHP (26.32% w/w) and AHPC (6.97% w/w) yields were achieved at 90 °C, pH of 1.4, 58.65 min, and liquid-solid ratio (LSR) of 20.13 v/w as the optimum point. In the next step, the solid residues that remained from the AHP and AHPC extraction process (PESR) were treated with cellulase enzyme and ultrasound and were used for simultaneous microbial production of PUL (34.29-24.56 g/L) and biomass containing SCP (19.31-13.44% w/w). Furthermore, the obtained results showed that AHP was low methylated (26.40%), rich in galacturonic acid (67.88%), and high in molecular weight (595.299 kDa). Also, the investigations of structural properties of AHP and PUL confirmed the presence of chemical structures of these polysaccharides in the formed supernatants. In addition, the AHPC showed considerable antioxidant activity compared with ascorbic acid (ASC) and BHA.

Heavy metal contamination remains a major threat to the environment. Evaluating the concentrations of heavy metals in water environments is a crucial step towards a viable treatment strategy. Non-cadmium photo-luminescent I-III-VI ternary QDs have attracted increasing attention due to their low toxicity and extraordinary optical properties, which have made them popular in biological applications. Recently, ternary I-III-VI-QDs have gained growing interest as fluorescent detectors of heavy metal ions in water. Here, we review the research progress of ternary I-III-VI QDs for the fluorescence detection of heavy metal ions in water. First, we summarize the optical properties and synthesis methodologies of ternary I-III-VI QDs. Then, we present various detection mechanisms involved in the fluorescence detection of heavy metal ions, which are mostly attributed to direct interaction between these unique QDs and the metal ions, seen in the form of fluorescence quenching and fluorescence enhancement. We also display the potential applications in environmental remediation such as water treatment and associated challenges of I-III-VI QDs in the fluorescence detection of Cu

The conventional Polyvinylidene Fluoride (PVDF) membrane was modified by polymerization Reversible addition−fragmentation chain-transfer (RAFT) with copolymer (PEGMA-co-BVIm-Br) on the upper bulk. This copolymer was obtained from the synthesis of (BVIm-Br) 3-butyl-1-vinyl-1-H-imidazole-3-ium bromide and the vinyl imidazole (VI) monomer N-vinyl imidazole (a hydrophilic monomer) and 1-bromobutane (C4H9Br). The analysis of such as ATR-FTIR, the magnetic resonance of H-NMR nuclei, zeta potential, Water Contact Angle (WCA), and Scanning Electron Microscopy (SEM) confirmed the presence of copolymer on the surface of the modified membrane. The bonding of this copolymer on the membrane surface reduced the WCA of the membrane water (from 89.5 ±1.96 to 33.8 ±1.55). The raw PVDF membrane (M1) and modified membrane (with total ratio-P(PEGMA-co-BVIm-Br) copolymer 2.5 % (M2), 5 % (M3), 10 % (M4), 20 % (M5), and 40% (M6) to (raw PVDF membrane) membrane showed appropriate hydrophilic nature and excellent separation of oil droplets from water/oil emulsions in the simulated effluent on the surface. This operation was performed for a comprehensive study on the determined parameters and by filtration with simulated petrochemical industry effluent (containing water/oil emulsion). Therefore, the recovery efficiencies of water flux, flow flux, oil recovery amount, as well as total fouling of M6 membrane were reported 96.14±0.99 and 428±2.6 L/ (m2 h), 96.1±1.3%, and 17.18±0.37%, respectively. This study aimed to prepare a copolymer-modified membrane that can show high performance in cleaning and resistance to various fouling, such as Rt, Rr, and Rir at the specified temperature, after long-term emulsion separation.

BACKGROUND The rind from cantaloupe is an agricultural waste of cantaloupe industrial processing. The current study tried to (i) evaluate the potential use of cantaloupe rind as a pectin source, (ii) optimize the factors of microwave-assisted extraction process using Box-Behnken design, and (iii) characterize the isolated pectin using various physicochemical, structural, functional and bioactivity properties. RESULTS Four variables of the extraction process were successfully optimized at a microwave power of 700 W, irradiation time of 112 s, pH value of 1.50 and liquid to solid (LS) value of 30 mL g-1 , with a yield of 181.4 g kg-1 . The analysis indicated a high-methylated galacturonic acid-rich (703.4 g kg-1 ) sample with an average molecular weight of 390.475 kDa. Also, the isolated pectin showed considerable functionality and antioxidant ability. The main functional groups, structural characteristics and crystallinity of samples were comparatively studied using Fourier transform infrared, nuclear magnetic resonance and X-ray diffraction spectroscopies. CONCLUSION In comparison to commercial citrus pectin, isolated pectin showed a significantly higher value for most of the functional analysis such as oil holding capacity, emulsifying capacity, emulsion stability, DPPH• and ABTS•+ scavenging activity, and reducing power assay. In other analyses the isolated sample was close to the commercial one, indicating that cantaloupe rinds should be considered as a suitable additional resource for pectin production. © 2021 Society of Chemical Industry.

The modification of membrane oxygenators to minimize protein adsorption onto the surface is often accompanied by the loss of membrane performance. This study aims to explore polyethersulfone (PES) as a new material for membrane oxygenator applications and to assess its potentials. Accordingly, different modification techniques are applied to improve surface properties of PES membranes. To achieve this goal, two separate modification methods including incorporation of TiO2 into the membrane matrix as well as grafting polyethylene glycol (PEG) through oxygen plasma treatment are developed and the effects are examined. The results reveal that protein adsorption to the nanocomposite membrane containing 0.50 wt. % TiO2 and the grafted membrane decreased by 47 and 31%, respectively. In terms of performance, permeability and oxygen transfer rate of all modified membranes exceeded 808 GPU and 2.7 × 10−4 mol·m−2·s−1, respectively. Contact angle analysis revealed signs of hydrophilicity enhancement of membranes after modifications. The findings suggest that upon proper modifications, membranes based on PES could be considered as promising candidates for membrane oxygenator applications and deserves further investigations.

Hydrazine is an inorganic chemical that has found use in various applications, such as fuel for jets, rockets, missiles and space shuttles. In the present study, polystyrene (PS) based membranes were developed and explored for hydrazine dehydration by pervaporation process. In addition to the separation performance, the physiochemical and morphological characteristics of the membranes were assessed and correlated to the findings. Investigation of the effects of structural and operating parameters revealed that increase in the membrane thickness enhanced selectivity and separation index (PSI) to 18.79 and 61, respectively. In addition, raising feed temperature from 36 oC to 56 oC caused increments in membrane flux, selectivity and PSI. However, increasing feed flow rate only improved water flux. Membranes exhibited reasonable flux and separation performance for the wide range of studied feed compositions. Two modification methods were employed to tailor the characteristics of PS membranes. Blending PS with acrylonitrile butadiene styrene (ABS) led to 27% improvement in total flux while selectivity and PSI reached to as high as 14.3 and 104.6, respectively. Also, nanocomposite membranes containing 2 wt% TiO2 exhibited total flux of 30.9 (g/m2·h) and PSI of 175.9.

In this study, kefiran was esterified with octenyl succinic anhydride (OSA). The esterification reaction variables including pH (8.5), kefiran concentration (5% (w/w)), OSA concentration (12% (w/w)), temperature (~38 °C) and reaction time (~80 min) were found as optimum points to achieve the maximum degree of substitution (DS) (0.041 ± 0.002). Kefiran-OSA samples with DS of 0.021 (FDA suggested DS) and 0.041 (maximum DS) were prepared and compared with unmodified kefiran in all experiments. FTIR and 1H NMR spectroscopies proved the grafting of OSA on kefiran structure. XRD analysis revealed that with increase in DS, the physical state of kefiran to be more amorphous. In addition, the esterification modification led to a decrease in the degradation temperature and an increase in the apparent viscosity based on the obtained data from thermal analysis and viscosity measurement. The results of the foaming and emulsifying properties confirmed the improvement in surface properties of the modified kefiran. The frequency sweep test illustrated that with an increase in DS, the viscoelastic behavior of the kefiran cryogels to be more viscous. It can finally be stated that the modification with OSA was a high potential strategy to extend the industrial applications of the kefiran.

Pullulan (PU) is an exo-polysaccharide used in the food and pharmaceutical industries. However, the use of PU in different industries is limited due to its highly hydrophilic nature and consequently weakness in surface properties which can be remedied by its chemical modification with octenyl succinic anhydride (OSA). For this purpose, PU modification with OSA was optimized and the results showed that the maximum degree of substitution (0.061 ± 0.003) was obtained under pH of 9.0, pullulan concentration of 40% (w/w), temperature of ~40.90 °C, reaction time of ~101.21 min and OSA concentration of 14.96% (w/w). Also, the grafting of OSA on pullulan structure was confirmed by FTIR, 1H NMR and zeta-potential analyzes. Although this modification had no significant effect on the amorphousity of pullulan, it led to an increase in viscosity and a decrease in decomposition temperature and surface tension. Improvement of emulsifying properties of PU-OSA sample was proved by the evaluation of emulsifying capacity of un- and modified samples and also, zeta-potential, particle size and viscosity of the prepared emulsions. In line with surface characteristic results, an increase in foam capacity of modified samples was observed with decreasing the interfacial tension.

In recent years, polyaldehyde polysaccharides have received an increasing attention as an ideal cross-linker which their aldehyde groups can be crosslinked with amino groups of enzyme. In this study, pectinase was covalently immobilized on the glass beads by polyaldehyde pullulan as the resulting product from periodate oxidation of this polysaccharide and by glutaraldehyde as a common cross-linker. Polyaldehyde pullulan had an aldehyde content of 19.9 ± 1.3%, which was confirmed by FTIR. The protein content of glass beads after enzyme immobilization by polyaldehyde pullulan and glutaraldehyde was 1.83 and 0.41 mg/10 glass beads, respectively. Optimum pH and temperature for pectinase immobilized by both cross-linkers were 5.5 and 50 °C, and the specific activity under these conditions was 2.21 ± 0.18 and 2.56 ± 0.12 unit/mg for enzyme immobilized by polyaldehyde pullulan and glutaraldehyde, respectively. pH stability of the pectinase immobilized by polyaldehyde pullulan was higher than by glutaraldehyde, while both immobilized system has an almost similar temperature stability. The kinetic parameters were determined for both immobilization systems. Also, SEM and atomic force microscopy confirmed the presence of polyaldehyde pullulan on glass bead after immobilization. Eventually, the obtained results suggested that polyaldehyde pullulan can be applied as a high potential alternative to glutaraldehyde for the enzyme immobilization.

Background: Late adulthood, as a sensitive life period of humans, requires unique attention. Elderly people are faced with challenging conditions, including death anxiety. This research aimed to investigate the relationship between religious attitudes and death anxiety in the elderly population of Gonabad City, South Khorasan Province, Iran. Methods: It was a cross-sectional and correlational study. The study sample included 200 adults older than 60 years. The sample is collected from the adult population of Gonabad City using the random sampling method. The obtained data were analyzed with G Power 3.0.10 software. The religious attitudes questionnaire of Khodayarifard et al. was used to evaluate four religiosity dimensions: religious convictions, affections, behaviors, and social pretensions. A high score in each subscale implies greater religiosity tendencies. The Templer questionnaire was also used to assess the anxiety of death. This questionnaire includes the fear of death; the fear of pain and disease; the thoughts of death, passing time, and shortening life; and the fear of the future. The data were analyzed with the Mann-Whitney, Kruskal-Wallis, and Spearman tests. Results: The religious attitudes were inversely correlated with death anxiety. This implies that the anxiety has decreased as religious attitudes have increased. This research showed a relationship between death anxiety and the population variables (education level, the source of revenue, etc.) This study also indicated a connection between religious attitudes and population variables (marital status, educational level, the source of revenue, lifestyle, and financial status). Conclusion: According to the present findings, a better religious approach could improve mental health and decrease death anxiety among elderly people.

The ultrasound-assisted extraction of pectin from walnut processing waste was optimized by Box-Behnken design. The highest extraction yield (12.78 ± 0.83%) was obtained at ultrasound power of 200 W, sonication time of 10 min, pH of 1.5 and LS ratio of 15 v/w. The resulting pectin in these conditions was rich in galacturonic acid (69.44%) and was high in degree of esterification (59.21%) which was confirmed by NMR and FTIR spectra. In addition, the molecular weight distribution analysis showed that the obtained pectin had a heterogeneous natural with low molecular weight (6.30–158.48 kDa). The XRD spectrum of the walnut pectin showed an amorphous structure with few crystalline portions. Furthermore, walnut green husk pectin had good emulsifying properties, water and oil holding capacities, and radical-scavenging activity. Given that the obtained result, the extraction of pectin from this by-product in addition to being able to reduce environmental problems, it can also provide financial benefits for the walnut production sector.

In this study, Box–Behnken design was applied to optimize the ultrasound-assisted extraction (UAE) and heating extraction (HE) conditions for pectin production from pistachio green hull (PGH). The pectin extraction yield at optimal condition for UAE (ultrasound power of 150 W, pH of 1.5 and time of 24 min) and HE (temperature of 70 °C, time of 90 min and liquid to solid ratio of 40 v/w) methods was about 12.0 and 10.3%, respectively. In these conditions, the galacturonic acid content of UAE-pectin and HE-pectin was about 59.33 and 75.11%, respectively. Both pectin samples showed good emulsifying activity, water holding capacity and oil holding capacity. In addition, total phenol content, antiradical and surface activities of HE-pectin were higher than UAE-pectin. The degree of esterification of pectin produced by the HE method was higher than the UAE method, which was confirmed by FT-IR and 1H-NMR analysis. The results of XRD patterns showed an amorphous structure with several crystalline portions for PGH pectin. The rheological properties of pectin solutions illustrated that in high frequencies, both pectin samples had a similar behavior (elastic), while in low frequencies, HE-pectin showed a viscous behavior. In the final, it should be stated that the UAE method significantly increased pectin yield using a lower processing time and consumed solvent, however, HE-pectin presented a better quality in comparison to UAE.

In this study, the effect of marjoram essential oil (MEO) on the mechanical, barrier, antioxidant and antimicrobial properties of mung bean protein isolate (MPI)/pullulan (PU) composite films and its influence on the quality of minced beef meat during 14 days storage at 4 °C was studied. The Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) results confirmed the compatibility between components. Also, depend on the different ratios of combination of MEO and MPI/PU, tensile strength (TS) and elongation at break (EAB) were varied. The results showed that an increase in the level of the MPI led to a significant increment in TS and water-proof properties of the composite films. Also, with addition of MEO, the EAB of the antimicrobial blend-films was decreased, while TS and water-proof properties were increased. In addition, enrichment of the films with MEO led to a considerable positive effect on DPPH radical scavenging and antibacterial activity against pathogenic bacteria (Staphylococcus aureus and Escherichia coli). Based on the bacterial and chemical analyses of the minced meat samples, MEO-incorporation in MPI/PU films enhanced oxidative stability of minced beef samples, and also showed effective antimicrobial activity against all of the tested bacteria.

Adsorption is commonly used as an industrial process for biogas upgrading through elimination of unwanted species to obtain high quality biomethane. While several studies have addressed individual removal of CO2 and N2 from raw biogas, limited attention has been paid to their simultaneous removal due to the complexities involved. This works presents the results of design, modeling, and numerical simulation of a novel vacuum pressure swing adsorption (VPSA) process for upgrading a model raw biogas containing 40 and 10 vol% CO2 and N2, respectively, to increase CH4 purity to 98% and with less than 2 % N2. The proposed process is comprised of 4 columns including two columns of carbon molecular sieves (CMS) and two others with zeolite Sr-ETS-4 as the selective adsorbents for removal of CO2 and N2, respectively. Two configurations are evaluated and compared in terms of CH4 purity, CH4 recovery, productivity, energy consumption, and 2nd law efficiency. For the best configuration, an energy consumption of 24.9 kJ/mol CH4, productivity of 3.38 mol h−1 kg−1, CH4 purity of 98.2 mol%, and CH4 recovery of 73.8 mol% were achieved. 15% improvement in CH4 recovery in comparison to the basic configuration is obtained. The findings highlight the importance of adsorbent selection and process configuration for achieving high separation performance.

Eggplant peel as a new source was used for pectin extraction using ultrasonic method. The extraction process factors were optimized using Box-Behnken design (BBD) and under optimal conditions (ultrasound power of 50 W, irradiation time of 30 min and pH of 1.5), the predicted extraction yield (35.36 g/100 g) was validated by the experimental results (33.64 ± 1.12 g/100 g). The eggplant peel pectin (EPP) was examined in terms of chemical, physicochemical, functional and structural features. The results indicated that the EPP was rich in galacturonic acid (66.08g/100 g), high in degree of esterification (61.22%) and total phenolic content, and low in ash and protein content. Also, EPP had a suitable value of water and oil holding capacity, emulsifying properties, antioxidant activity, and foam capacity. In addition, FT-IR and 1H NMR spectroscopy proved the existence of pectin structure in the obtained samples and XRD pattern suggested a high crystallinity in EPP.

In this work, a Box-Behnken design (BBD) with three variables (ultrasound power, irradiation time and pH) in three levels was applied for pectin extraction optimization. The optimization process showed that the maximum extraction yield was 28.07 ± 0.67% in ultrasound power of 150 W, irradiation time of 10 min and pH of 1.5 (as optimum conditions). In these conditions, ash, moisture and protein contents of SOPP were 1.89 ± 0.51, 8.81 ± 0.68 and 1.45 ± 0.23%, respectively. HPLC analysis indicated that 65.3% of the extracted pectin was galacturonic acid and approximately 72% of total neutral sugars was galactose. The optimized pectin had a total phenolic content of 39.95 ± 3.13 mg gallic acid equivalents/g pectin, the surface tension of 46.56 ± 0.23 and 42.14 ± 0.61 mN/m in concentrations of 0.1 and 0.5%w/v, water holding capacity and oil holding capacity of 3.10 ± 0.12 and 1.32 ± 0.21 g water or oil/g pectin with a suitable emulsifying and antioxidant properties. In addition, SOPP with degree of esterification of 6.77 ± 0.43% was classified as low methoxyl pectin, which confirmed by FTIR and 1H NMR analysis.

Polydimethylsiloxane (PDMS) mixed matrix membranes (MMM)s containing microporous adsorptive carbon nanoparticles (ACNs) are developed for CO2/CH4 and C3H8/CH4 separation. The ACNs are produced by the pyrolysis of a phenolic resin precursor at 700 °C and transformed into fine particles through ball-milling. For functionalization of the particles and widening of the pores, the prepared ACNs undergo ozone treatment to increase the sorption capacity and to reduce diffusional limitations. Successful accomplishment of modification is evidenced by pore size distribution, X-ray diffraction, and Fourier transform infrared spectra analyses. MMMs containing different amounts of both native ACNs (ACN-N) and oxidized ACNs (ACN-O) are evaluated in terms of permeability, solubility and diffusivity coefficients for target gases. Based on the results, higher pressure and lower temperature promote gas separation due to capillary condensation of penetrants in the micropores of the particles present in the MMMs. Activation energy of permeation, diffusion, and enthalpy of sorption are also determined for MMMs and compared to the pure PDMS membrane. The real selectivity in PDMS/ACN-O (10%) membrane for CO2/CH4 and C3H8/CH4 are 57.3% and 53.1% higher than those in pure PDMS membrane. This enhancement is attributed to the selective adsorption and surface diffusion of the more adsorbable component in ACNs as well as partial diffusion hindrance of less adsorbing component (CH4) in the presence of more adsorbable component (e.g., CO2, C3H8) onto the surface of ACN pores. Also, CO2 and C3H8 permeability improved by 61.6% and 47.7% respectively, compared to the pure PDMS membrane and is attributed to the formation of extra free volume in PDMS matrix as a result of chain packing disruption in the presence of ACNs. According to the findings, the fabricated membranes are promising candidates for natural gas sweetening and hydrocarbon recovery.

The optimal microwave-assisted extraction conditions of pistachio green hull (PGH) pectin (extraction yield of 18.13%) were in microwave power of 700 W, irradiation time of 165 s, and pH of 1.5. The physico-chemical, structural and functional properties of pectin was examined and the results showed that PGH pectin under optimum conditions was low methoxyl (about 12.1%) with molecular weight of 1.659 kg/mol, emulsifying activity of 58.3%, total phenolic content of 18.18 mg GalAE/g pectin and good surface activity (46.23 and 49.75 mN/m at 0.1 and 0.5% w/v). Also, high performance liquid chromatography analysis illustrated that the pectin is including galacturonic acid (66.0%), arabinose (26.2%), galactose (3.7%), rhamnose (2.7%) and xylose (1.0%). In addition, 1H NMR and FTIR spectrums confirmed the presence of pectin in obtained supenatnt. Surface morphology analysis and X-ray diffraction pattern showed that PGH pectin had a rough surface with crystalline structure.

This study presents a mathematical modeling approach for developing models based on non-ideal conditions related to the membrane structure including porous supporting layer and deformation under pressure. Comparison of the findings with experimental data reveal the importance of considering the resistance in porous supporting layer though the effect of concentration polarization in the permeate stream could be neglected. Investigations on deformation of fibers under pressure ascertain that at larger fiber inner radius to outer radius ratios, increasing driving force may lead to an initial increase in permeability. After that, the effects of deformation dominates and thus permeability may be decreased.

In this study, to improve the water resistance properties of pullulan (PU) edible-films, the combination of the modification with octenyl succinic anhydride (OSA) and beeswax (BW) incorporation was used. The FTIR spectra results confirmed the PU octenylsuccination and also the presence of the BW in the composite films. The scanning electron microscopy (SEM) micrographs showed that the PU modification with OSA powerfully retarded the coalescence of BW droplets in film casting process and led to their homogeneity in the dried films. Also, the findings indicated that the water-proof properties including water solubility, water vapor permeability and water contact angle in the PU films were improved by the PU modification and BW incorporation. In addition, the obtained data showed that the octenylsuccination of PU had a negative effect on the mechanical properties of the produced films, while BW incorporation into PU-OSA films led to resolve this drawback.

In this study, a new strain suspected to be Aureobasidium pullulans was isolated from trees leaves. The molecular characterization and the resulting phylogenetic tree showed that the isolated strain was A. pullulans. Also, the results of methylation analysis, monosaccharide composition, FTIR, NMR and XRD confirmed that the obtained exo-polysaccharide from the mentioned strain was pullulan. The pullulan production optimization by central composite design (CCD) indicated that the maximum yield obtained under optimum conditions (pH of 6.5, sucrose concentration of 5.5% (w/v) and yeast extract concentration of 0.1% (w/v)) was 51.4 ± 0.50 g/L. The produced pullulan had an average molecular weight (Mw) of 2.07 × 105 g.mol−1 based on gel permeation chromatography results. The decomposition temperature (Td) of the produced pullulan was ~300 °C and also, the resulting pullulan had a Newtonian flow behavior in a wide range of concentrations.

ZIF-8 nanocrystals were synthesized in the presence of cetyltrimethylammonium bromide, as a cationic surfactant, (ZIF-8@CTAB) and then modified by iron promoter (ZIF-8@Fe-CTAB) through a wet impregnation process. Self-assembly of surfactant in the synthesis route changed morphology of ZIF-8 nanocrystals from rhombic dodecahedron (RD) to truncated rhombic dodecahedron (TRD). The structural modifications significantly changed the adsorption properties of the nanocrystals for CO2 and CH4, so that ZIF-8@Fe-CTAB nanocrystals provided the highest CO2/CH4 adsorption selectivity ( ∼ 19) compared to values have ever been reported in the literature. The nanocrystals were also employed for preparation of mixed matrix membranes (MMMs) using Matrimid®5218 as the polymeric matrix. Investigation of gas transport properties of the MMMs confirmed promising separation performance of ZIF-8@Fe-CTAB nanocrystals for CO2/CH4 separation.

In this study, novel membranes are designed and fabricated using CTA as the main matrix with contributions of PEG and as-synthesized ZIF-8 nanoparticles. Gas permeation properties of blend membranes containing 25–45 wt.% PEG and MMMs containing 2–20 wt.% ZIF-8 crystals are evaluated for the separation of He from N2 and CH4 at various temperatures and pressures. The properties of synthesized ZIF-8 nanoparticles as well as membranes are well characterized. Among all the prepared membranes, the MMMs membrane with composition of CTA/PEG/ZIF-8 (60/20/20 wt.%) exhibits the best performance (PH2 = 73.25 Barrer) for He/N2 (α = 43) and He/CH4 (α = 40) separations. In addition, various predictive permeation models are investigated in order to gain more insights about the systems and for validation of the experimental results. The %AAREs of the models are high, while the best value is obtained by applying the Maxwell model (5.98). Also, by choosing Lewis–Nielsen model and taking into account some of the non-ideal effects such as particle pore blockage, polymer chains rigidification as well as the effect of particles size on the rigidified layer thickness, a new while accurate model is proposed. Finally, the accuracy of the newly developed model is examined utilizing several experimental data.

In receiving terminal, liquid natural gas (LNG) needs to be re-gasified by the ambient heat generally supplied by seawater. Unfortunately, a great amount of LNG cold energy is wasted during this process, resulting in energy inefficiency and environmental implications. Seawater freezing desalination (SFD) should be an effective way to use cold energy of LNG in terms of energy match and operation cost. According to the properties of LNG, this work aims to develop a direct contact type ice generator, which integrating some special designs such as jacketed cylinder, nozzle arrangement and gas floatation, in order to improve heat transfer and phase separation in the SFD process. Through dynamic analysis on refrigerant atomization, the changes in speed and diameter of refrigerant droplet are obtained. The analysis results are helpful to further improve the design and operation of ice generator. In addition, the work also experimentally investigated the effects of some predominate factors on determining overall performance of ice generator, comprehensively considering ice generation and desalination. The experimental results could be significant for the SFD project by using cold energy of LNG.

In this study, the effect of acidic extraction conditions (time of 30–90 min, temperature of 75–95 °C and pH of 1.5–3) on the yield and degree of esterification (DE) of citron peel pectin was investigated applying Box–Behnken design. The highest production yield of pectin (28.31 ± 0.11%) was achieved at extraction time of 90 min, temperature of 95 °C and pH of 1.5, as optimal extraction conditions, which was close to the predicted value (29.87%). Under optimum extraction conditions, the DE and the emulsifying activity were 51.33 and 46.2%, respectively. In addition, the emulsions were 93.9 and 93.5 stable at 4 °C, 93.7 and 93.1 at 23 °C after 1 and 30 days, respectively. The determination of flow behavior showed that the pectin solutions had a Newtonian behavior at low concentrations (

The octenyl succinic anhydride (OSA) modification of pullulan (PU) was applied to improve the blend miscibility, compatibility and water-resistance properties of the PU-chickpea protein isolate (CPI) blend films. For this purpose, the effect of degree of substitution (DS) of the modified PU and also the ratio of CPI to PU-OSA on the physical and mechanical properties of the obtained composite films were evaluated. FTIR and XRD results showed that the molecular interactions between CPI and PU-OSA were more than CPI and PU, indicating that these two polymers had more miscibility because of the hydrophobic nature of PU-OSA which also confirmed by scanning electron microscope (SEM) pictures. The findings indicated that the use of PU-OSA instead of PU can significantly improve the mechanical and water-resistance properties of composite films. In this regard, the octenylsuccination of PU decreased the extensibility, moisture content and water vapor permeability, while increased the tensile strength and water contact angle of the produced composite films. The highest values of the tensile strength (8.90 ± 0.10 MPa) and contact angle (91.48 ± 0.34°) were obtained for CPI50–P3 and CPI70–P3 composite films, respectively. Also, the lowest values of the water solubility (21.23 ± 0.96%), moisture content (15.74 ± 0.47%) and water vapor permeability (2.07 ± 0.06 × 10-10 gm-1s-1pa-1) were obtained for CPI70–P3 blend film. Eventually, it can be deduced that the composite films produced by CPI and PU-OSA with DS of 0.06 are the best and can be used as new biodegradable films with excellent properties.

Helium is a valuable gas with unique properties and applications and still the prominent industrial source of helium is natural gas. Because of several advantages of membrane-based separation processes over conventional methods as well as the lack of a comprehensive scientific report, the present study aims to investigate the advances in design and modification of organic and inorganic membranes and materials including pure polymers, mixed matrix membranes, polymer blends, copolymers, ceramics as well as carbon molecular sieves for separation and recovery of helium from methane and nitrogen. In overall, inorganic membranes such as silica have shown good performance in helium separation, but production of such membranes has not yet become viable on the commercial scale. On the other hand, polymeric membranes are low-priced, but their performance is relatively low with much room for improvements. One of the most effective methods to enhance the performance of these membranes is synthesizing copolymer membranes consisting of alternatively flat and bulky segments. Also, alternations in the membrane configurations as well as hybridization of membranes with cryogenic and pressure swing adsorption processes are among the valuable options for optimizing techno-economical viability of helium separation and purifcation.

In this study, the effect of aqueous extraction conditions (temperature of 70-90°C, time of 60-180min, and liquid/solid ratio (LSR) of 20-40v/w) on the yield and degree of esterification (DE) of Citrus medica peel pectin was studied using a Box-Behnken design. The highest production yield of pectin (21.85±0.35%) was obtained at temperature of 90°C, extraction time of 180min and LSR of 40v/w as optimum extraction conditions which was close to the predicted value (24.13%). In these extraction conditions, the DE and the emulsifying activity were 77.2 and 46.5%, respectively. Also, the emulsions were 90.30 and 90% stable at 4°C, and 83.87 and 83.50% at 25°C after 1 and 30days, respectively. The determination of flow behavior showed that the pectin solutions had a Newtonian behavior at low concentrations (0.1, 0.5 and 1.0%w/v), while in higher concentration (2.0%w/v), the pseudoplastic flow behavior became dominant.

In this study, corn bran hydrolysates, as an inexpensive carbon source, were used to produce the pullulan biopolymer by Aerobasidiom pullulans KY767024. The enzymatic hydrolysis of corn bran was done in the presence of α-amylase and glucoamylase enzymes and the obtained results by HPLC analysis confirmed that the glucose concentration in corn bran was significantly increased after hydrolysis process. Also, the pullulan production optimization by Box-Behnken Design showed that the maximum yield (19.45 ± 0.40 g/L) was obtained after 96 h under optimum conditions (pH 5.5, yeast extract concentration of 0.2% w/v and corn bran hydrolysates concentration of 20% w/v). The results of FTIR, H NMR and XRD spectroscopies confirmed the presence of the chemical structure pullulan in the obtained supernatant. The weight–average molecular weight of the produced pullulan was determined to be 1.22×105 gmol−1 based on the gel permeation chromatography. Besides, the thermal decomposition temperature (Td) of the obtained pullulan was ~ 280 °C showing that the resulting sample had a good thermal stability. Also, the obtained sample solution had a Newtonian flow behavior in a wide range of concentrations.

In this paper, the influence of pH (0.5-2.5), temperature (50-90°C), extraction time (30-150min) and liquid/solid ratio (10-50v/w) on the acidic extraction yield and degree of esterification (DE) of pistachio green hull pectin were studied by using central composite design. The results indicated that the yield and DE of pectin ranged from 7.31 to 19.02% and 26.00 to 53.01%, respectively. The optimization of pectin extraction condition showed that the optimal condition was pH of 0.5, temperature of 90°C, time of 30min and liquid/solid ratio of 50 v/w. In this condition, the experimental yield (22.1±0.5%) was fine accord among predicted yield (23.42%). Also, under the optimal extraction condition, the galacturonic acid content of pectin was about 65%. The FTIR spectrum showed that the pectin extracted under optimal condition is rich from polygalacturonic acid.

In this study, acidic extraction (citric acid) was used for the extraction of pectin from melon peel. A central composite design (CCD) was applied to study the effect of temperature (35-95°C), time (40-200min), pH (1-3) and solvent to sample ratio (10-50v/w) on the yield and degree of esterification (DE). The results showed that the yield and DE ranged from 2.87 to 28.98% and 1.33-29.33%, respectively. Also, the highest extraction yield (29.48±1.7%) was obtained under optimal conditions (pH of 1, temperature of 95°C and ratio of 10v/w after 200min). The protein, ash, carbohydrate and galacturonic acid content of pectin obtained under optimal conditions were about 1.5, 3.5, 10 and 48%, respectively. Rheological experiments determined that melon peel pectin dispersions behaved as a weak gel at concentrations of 1%w/v. The emulsifying activity was 35% and also, the emulsion stability was higher at 4°C than at 23°C.

In this study, the central composite design for four variables in five levels was applied to determine the effects of pH (0.5-2.5), temperature (50-90°C), heating time (30-150min) and liquid/solid ratio (10-50v/w) on the yield and degree of esterification (DE) of carrot pomace pectin. The results showed that the pectin yield ranged from 5.0 to 15.2% and also, this pectin is classified as low methoxyl pectin (DE of 22.1-51.8%). The pH of 1.3, temperature of 90°C, time of 79.8min and liquid/solid ratio of 23.3v/w were determined as optimal conditions with a maximum yield of 15.6±0.5%, which was close to the predicted values (16.0%). Under the optimal extraction conditions, the galacturonic acid content and emulsifying activity were 75.5 and 60.3% respectively; moreover, the emulsions had a high stability at two different storage temperatures (4 and 23°C). Furthermore, carrot pectin solutions exhibited viscous and pseudoplastic behavior at 1% w/v.

Based on a bio-refinery concept, the valorization of eggplant peel wastes (EPW) in the production of multiple value-added products was aimed. The acid-free extraction process was applied in the simultaneous recovery of pectin and phenolic compounds. The extraction variables were optimized by response surface methodology using a Box-Behnken design and the maximum yield of pectin (26.1%) and phenolic compounds (20.2%) was obtained in the extraction temperature of 90 °C, time of 90 min and liquid/solid ratio of 40 mL/g. After recovery of pectin and phenolic compounds from EPW, the solid leftovers were enzymatic hydrolyzed and the hydrolysates were used as a carbon source in the microbial production of pullulan by Aureobasidium pullulans. The produced pectin and pullulan were characterized through the chemical and structural features. The results of FT-IR and H-NMR analysis approved the predominant presence of these two polysaccharides in the isolated samples. On the other hand, the antioxidant activity of the recovered phenolic compounds extract was evaluated by DPPH and ABTS radical scavenging activity and reducing power assay.

In this study, a new yeast-like fungal was obtained from leaf surfaces collected from Kheyroodkenar forest, Mazandaran, Iran. The properties of this strain, such as morphology, DNA molecular, and product showed that it is related to Aureobasidium pullulans family and named A. pullulans MG271838. The pullulan production conditions by this strain were optimized using a Box-Behnken design. The results showed that the optimum production yield (37.55 ± 0.45 g/l) was obtained in pH of 6.76, sucrose concentration of 6%w/v and yeast extract concentration of 0.2%w/v. The pullulan had a concentration-dependent flow behavior, amorphous structure based on XRD pattern and high thermal stability (decomposition temperature of 300 °C). Also, the chemical structure of pullulan was confirmed by FTIR spectroscopy. In addition, there was a direct relationship between pullulan yield and the gene expression of fks, pgm and ugp as the most important genes in pullulan production.

A continuous clarification of grape juice was undertaken in a packed bed reactor (PBR) using pectinase enzymes immobilized on glass beads. The enzyme immobilization process decreased the specific activity and the volumetric productivity from 3 ± 0.2 to 2.7 ± 0.1 units mg−1 and from ~0.085 to ~0.070 mg mL−1 min−1, respectively. Also, it increased the optimum pH from 5.0 to 5.5, but did not influence the optimum temperature (50 °C). The best conditions for clarification of the grape juice were obtained at a flow rate of 0.5 mL min−1 and a treatment time of 42 min. After clarification, pH, total soluble solids, turbidity, total phenolic content, antiradical activity and viscosity of grape juice were decreased, and on the other hand, total titratable acidity and the color parameter L were increased. Generally, this study showed that the continuous operation in a PBR including glass bead immobilized enzyme can be a potential alternative for the batch system used in juice industries.

In this study, the glutaraldehyde, polyaldehyde pullulan and polyaldehyde kefiran were applied to immobilize the pectinase on the silanized glass bead and then a packed bed reactor (PBR) was used to continuous clarification process of the pomegranate juice. The results showed that the bioreactor packed with the enzymes immobilized by all three cross-linkers had the best performance at the temperature of 50 °C, a flow rate of 0.5 mL/min and treatment time of 42 min. After the clarification process, the turbidity of the pomegranate juice was significantly decreased from ~70.2 to ~17.4 NTU and the clarity of the samples was increased from ~81.15 to ~96.13%. The findings showed the clarification process had a significant effect on the pomegranate juice properties so that the total titratable acidity, reducing sugar content and lightness parameter were increased while pH, total soluble solids, viscosity, total phenol content and radical scavenging activity of the juice samples was decreased by this process. Finally, it must be stated that the bioreactor packed with polyaldehyde kefiran-immobilized pectinase had the best performance in the clarification of pomegranate juice due to the higher capacity of this cross-linker in the pectinase immobilization.

Natural and modified zeolite and bentonite are investigated and characterized for extraction of magnesium from aqueous solutions. Magnesium removals as high as 85.21% and 81.73% were achieved by calcined bentonite and microwave radiated zeolite, respectively. The effects of various operational parameters were studied and optimized using selected isotherms. Maximum Mg (II) adsorption capacities of 26.24 and 35.67mg·g−1 were obtained on pristine and calcined bentonites, respectively. Thermodynamic studies suggest that magnesium adsorption on natural bentonite is spontaneous and endothermic (9.13 kj·mol−1). Also, desorption study of natural bentonite demonstrates that HNO3 is more effective by offering 89.11% desorption than other desorptive counterparts.