Effect Of Different Carriers Research Articles

Preparation of palladium‐based catalysts and use for depolymerization of larch bark tannins

AbstractIn this study, we synthesized eight palladium‐based catalysts using two carriers, ZrO2 and MCM‐41. These catalysts were used for the degradation of condensed tannins extracted from larch bark. The average polymerization degree and degradation rate of the products were used as indicators to evaluate the efficiency of degradation. The effects of different Pd:Cu loading ratios under the same carrier conditions and the effects of different carriers under the same Pd:Cu loading ratio were investigated. The results revealed that when the carrier was kept constant, the Pd:Cu ratio of 1:1 exhibited the highest efficiency in degrading condensed tannins. Moreover, when the Pd:Cu loading ratio was the same, the degradation efficiency was higher when ZrO2 was used as the carrier. Based on these findings, the catalyst (Pd1‐Cu1)5/ZrO2 (where “1” are the molar ratios of Pd to Cu added during the preparation of the catalyst and where ‘5’ is the mass percentage of Pd/Cu metal to total catalyst, i.e., 5 wt%), with ZrO2 as the carrier and a Pd:Cu ratio of 1:1, demonstrated the highest degradation efficiency, with a degradation rate of 73.89%. This catalyst successfully reduced the average polymerization degree of condensed tannins from 9.5 to 2.48.

Freeze-Drying Microencapsulation of Hop Extract: Effect of Carrier Composition on Physical, Techno-Functional, and Stability Properties.

In this study, freeze-drying microencapsulation was proposed as a technology for the production of powdered hop extracts with high stability intended as additives/ingredients in innovative formulated food products. The effects of different carriers (maltodextrin, Arabic gum, and their mixture in 1:1 w/w ratio) on the physical and techno-functional properties, bitter acids content, yield and polyphenols encapsulation efficiency of the powders were assessed. Additionally, the powders' stability was evaluated for 35 days at different temperatures and compared with that of non-encapsulated extract. Coating materials influenced the moisture content, water activity, colour, flowability, microstructure, and water sorption behaviour of the microencapsulates, but not their solubility. Among the different carriers, maltodextrin showed the lowest polyphenol load yield and bitter acid content after processing but the highest encapsulation efficiency and protection of hop extracts' antioxidant compounds during storage. Irrespective of the encapsulating agent, microencapsulation did not hinder the loss of bitter acids during storage. The results of this study demonstrate the feasibility of freeze-drying encapsulation in the development of functional ingredients, offering new perspectives for hop applications in the food and non-food sectors.

Efficient conversion of furfural to furfural amine over 4Ru1Co/AC catalyst

The production of amine intermediates from biomass is capturing increasing attention. Herein, an efficient conversion of furfural to furfural amine over RuCo/AC catalyst under hydrothermal conditions has been investigated. The effects of different carriers, bimetals, and reaction conditions were systematically investigated in green solvents (water). Fully conversion of furfural and high furfural amine yield (92.13%) at 80 ℃ for 1 h over 4Ru1Co/AC. The excellent catalytic performance of 4Ru1Co/AC was attributed to its high acidity and good hydrogenation ability, as well as the synergistic effect between Ru-Co alloy formations and the activated carbon. Importantly, the highly selective preparation of furfural to furfural amine is a promising way to high-value utilization of cellulosic biomass in green solvents.

Effects of different carriers for zinc oxide (ZnO) particles on microstructure of ZnO/layered silicate composite and aging resistance of composite modified asphalt

• ZnO/layered silicate composite with three different carriers is synthesized. • Adding EVMT can significantly weaken agglomeration effects of ZnO particles. • Introducing ZnO particles can enhance UV absorption ability of layered silicates. • Exfoliated phase structure is formed in ZnO/MMT or ZnO/EVMT modified asphalt. • EVMT and REC are preferable to form composite and improve asphalt aging resistance. With the use of nanocomposite synthesis operations, the produced zinc oxide/expanded vermiculite (ZnO/EVMT) composite, a combination of ZnO particles and EVMT, has ZnO particles of the weakened agglomeration effects and can comprehensively improve the resistance of asphalt to thermo-oxidative and ultraviolet (UV) aging. However, the effects of different carriers for ZnO particles on the microstructure of ZnO/layered silicate composite and aging resistance of the composite modified asphalt are still unknown. In this research, three ZnO carriers, montmorillonite (MMT), expanded vermiculite (EVMT) and rectorite (REC), were employed to support ZnO particles (named ZnO/MMT, ZnO/EVMT and ZnO/REC, respectively). Then, the microstructure of different ZnO/layered silicate composites was investigated by field emission scanning microscope (FESEM), X-ray diffractometer (XRD) and UV–visible spectrometer (UV–vis) tests. Finally, the effects of different carriers on the morphology, phase structure, storage stability, physical properties and aging resistance of ZnO/layered silicate composite modified asphalt were discussed. Results showed that with the unique layered structure and its integrity, the three carriers are feasible to synthesize ZnO/layered silicate composite, and ZnO particles are supported or embedded on the surface of layered silicate sheets and have weaker agglomeration effects. Except for ZnO/MMT composite, the other two composites have sufficient composition connection strength. The exfoliated phase structure is formed in the ZnO/MMT or ZnO/EVMT composite modified asphalt systems. Additionally, the three ZnO/layered silicate composites have good asphalt compatibility and storage stability in asphalt, especially for ZnO/REC composite. The addition of ZnO/layered silicate composites into asphalt slightly influences physical properties of asphalt. Incorporating ZnO/layered silicate composites, regardless of the types, into asphalt could comprehensively enhance the resistance of asphalt to thermo-oxidative and UV aging. Comparatively, EVMT and REC are preferable to support ZnO particles and generate ZnO/layered silicate composite and comprehensively improve the aging resistance of asphalt.

Selective adsorption and efficient degradation of oil pollution by microorganisms immobilized natural biomass aerogels with aligned channels

Efficient elimination of organic pollution from wastewater is of great importance for sustainable human development. In this paper, natural biomass of lotus root (LR) and sorghum straw (SS), which showed aligned structure after treatment, was used to prepare efficient, low-cost, selective adsorption and self-floating microbial immobilization materials by hydrophobic modification assembly for the efficient degradation of diesel. By immobilizing microorganisms in aligned structured lotus flower (ALR) and sorghum straw (ASS) aerogels, hydrophobically modifying the aerogel surfaces with SiO2/PDMS, and assembling them with polyurethane foam to form hydrophobically immobilized microbial bilayer structured self-floating composites (SA6-ALR4@SiO2/PDMS and SA6-ASS4@SiO2/PDMS), diesel in water can be selectively adsorbed for biodegradation. The kinetic and thermodynamic parameters of diesel degradation process were investigated by treating oily wastewater and the effect of different carriers on microbial tolerance under different factors (temperature, pH, degradation substrate concentration, salinity) was examined. The results showed that the different carriers were effective in the degradation of diesel. However, the rich vertical aligned channels and excellent self-floating characteristics of SA6-ALR4@SiO2/PDMS accelerated the mass transfer rate between microorganisms and pollutants, achieving a high degradation rate of 96.25% for diesel in 276 h, which was better than that of 33.06% for free microorganisms under the same conditions. The degradation of oily wastewater by immobilized microorganisms follows first order kinetics. Moreover, this degradation process is spontaneous and the ΔG value is less than 0 at different temperatures. Compared with the existing methods using natural biomass to treat oily wastewater or applying only free microorganisms for biodegradation to remove oily wastewater, these methods have the disadvantages of poor selective adsorption, easy settling and low efficiency. It has greater advantages and application potential in on-site oil spill accident treatment, and opens up an effective green channel for the purification of oily wastewater.

A novel approach in the removal of ciprofloxacin antibiotic in an aquatic system using polymer inclusion membrane

Ciprofloxacin (CIP) in the aquatic environment has been widely studied due to its ability to be persistent in the environment. Residues of this contaminant are ubiquitous in different environmental media due to the inability of conventional wastewater treatment plants (WWTPs) to remove them completely. Various advanced wastewater treatments have been used to attenuate this contaminant; however, it remained refractory in the environment. In this study, we investigated the removal of ciprofloxacin using poly(vinyl)chloride (PVC) and cellulose triacetate (CTA) based polymer inclusion membranes (PIMs). Different parameters were investigated, such as the effect of the types of carriers (Bis-2-(ethylhexyl) phosphate (B2EHP) and tricapryl-methylammonium chloride (Aliquat 336), pH, initial concentration of feed solution, and concentration of the stripping solution. The produced PIM was chemically and mechanically stable. At optimum conditions, the removal efficiency of 99.2%, transport efficiency of 70%, and a permeability coefficient of 20.1 μ m/s were recorded using PVC/B2EHP membrane, whilst a removal efficiency of 95% was recorded using CTA/B2EHP membrane. However, using Aliquat 336 as the carrier, the highest removal efficiency of 60% was recorded. Finally, the PIM was used to remediate CIP in real environmental samples (river water and wastewater). From an initial concentration of 200 ng/L, it was reduced to 1.8 ng/L in river water and 2.2 ng/L in wastewater which is 99.1% and 98.9 % removal, respectively. Thus, PIM could be considered a suitable alternative for the removal of CIP in the aquatic environment. • Removal of CIP using polymer inclusion membranes (PIMs) was demonstrated. • Effects of different carriers, pH, feed and stripping solutions were investigated. • The removal efficiencies of the prepared PIMs are within 60%–99%. • The PIMs were used to remediate CIP in real samples, 98%–99% removals were achieved. • It may be used for the removal other recalcitrant antibiotics such as levofloxacin.

Microencapsulation of roselle (Hibiscus sabdariffa L.) anthocyanins: Effects of different carriers on selected physicochemical properties and antioxidant activities of spray-dried and freeze-dried powder

ABSTRACT Anthocyanins are abundant phytochemicals in nature that draw the public interest not only in their health effects, such as antioxidant, anti-inflammatory and anti-carcinogenic properties. It also showed their function in providing foodstuffs with appealing and distinctive color. In this study, anthocyanins from hibiscus (Hibiscus sabdariffa L.) calyces were microencapsulated by spray drying and freeze drying techniques using a wide variety of carriers including maltodextrin (MD), gum Arabic (GA) and their binary blends with inulin (INU) and konjac glucomannan (KON). The results showed that freeze-dried hibiscus powder using KON as carrier had the highest phenolic, anthocyanin and antioxidant activity, followed by spray-dried and freeze-dried MD/KON samples, which indicated the role of KON in the effective retention of antioxidants during the drying process. In addition, the ferric and cupric ion reduction activity (FRAP and CUPRAC) of the spray-dried samples was significantly higher than those of the freeze-dried powder. However, in terms of encapsulation efficiency (EE) of anthocyanins, KON was shown to be ineffective in entrapping these compounds in microcapsules with the lowest EE of freeze-dried KON and spray-dried MD/KON of 43.6% and 55.4%, respectively. By contrast, MD/GA was the most effective carrier, retaining anthocyanins inside the carrier matrix and limiting their loss to the surface of the microcapsules in both spray-drying and freeze-drying methods (EE of 91.8% and 95.7%, respectively). In addition, the moisture content of spray-dried powder samples was significantly higher than that of lyophilized powders, and the solubility of all samples was above 94.1%.

Effects of different carriers on physicochemical and antioxidant properties of freeze‐dried mulberry powder

The effects of three types of polysaccharides (dextrin, β-cyclodextrin, and maltodextrin) used as carriers at various levels (1%, 3%, and 5%) on the physicochemical and antioxidant properties of freeze-dried mulberry powders (MP) were investigated. The types and levels of carriers influenced moisture, solubility, total anthocyanin contents, and color profiles of MP. The MP produced with 5% of β-cyclodextrin (MP-C) and 5% of maltodextrin (MP-M) were found to have the highest solubility, retention ratio of anthocyanins, and color values among all the MP samples. The addition of β-cyclodextrin and maltodextrin decreased the particle size due to the increase of the spherical shape and the smooth surface. The MP-C and MP-M were found to show positive scavenging capacities on ABTS+ and DPPH radicals. Our results indicated that β-cyclodextrin and maltodextrin had the potential to be used as a carrier agent to produce freeze-dried mulberry powders. Novelty impact statement The types and levels of polysaccharide carriers influenced the physicochemical properties of mulberry powders. Mulberry powders produced with β-cyclodextrin and maltodextrin showed valuable physicochemical characteristics. Mulberry powders had potential scavenging activities on ABTS+ and DPPH radicals.

Effects of Carriers on ANAMMOX Sludge Activity Recovery and Microbial Flora Characteristics

In order to realize the rapid recovery of ANAMMOX sludge bacterial activity after long-term room temperature storage, three groups of reactors were added to ANAMMOX sludge that had been stored without substrate at room temperature (15-30℃) for 9 months. Among the three groups of reactors, comet fiber carrier and K3 carrier were added to R2 and R3 reactors, respectively, as biological carriers. The effects of different carriers on the recovery rate of ANAMMOX sludge bacterial activity were investigated. The results showed that ANAMMOX reactions in the R2 and R3 reactors began taking place on the 8th and 10th day, respectively, with respective TIN removal rates of 82.25% and 80.92%, which were significantly improved compared with that in the R1 reactor, in which no carrier was added (ANAMMOX reaction started occurring on the 15th day with a TIN removal rate of 80.26%). After 42 days with influent, ρ(NH4+-N) and ρ(NO2--N) respectively increased to 300 mg·L-1 and 396 mg·L-1, and the TIN removal rates of the three groups of reactors were respectively 78.96%, 84.92%, and 84.66%. Microbial community structure analysis showed that the relative abundances of ANAMMOX bacteria in the R2 and R3 reactor were respectively 6.85% and 6.06%, two to four times that in the R1 reactor. The predominant ANAMMOX bacteria in the sludge was Candidatus Jettenia, whose relative abundances in the three groups of reactors were respectively 1.62%, 5.74%, and 5.21%. The results show that ANAMMOX biofilm-granular sludge complex systems constructed by adding carriers can considerably shorten the time for recovering ANAMMOX sludge bacterial activity after long-term room temperature storage without substrate. The carriers effectively promoted the relative abundances of ANAMMOX bacteria in the reactors, whereas the promoting effect of comet fiber carrier was slightly more significant than that of the K3 carrier.

Catalytic Upgrading of Bio‐Based 5‐Hydroxymethylfurfural to 2,5‐Dimethylfuran with Non‐Noble Metals

2,5‐Dimethylfuran (DMF) is considered one of the most promising liquid transport fuels due to its high energy density, high boiling point, high octane number, and immiscibility with water. It can be obtained mainly by hydrogenolysis of biomass‐derived 5‐hydroxymethylfurfural (HMF) over metal catalysts. This review describes the latest research progress of developing various non‐noble metal catalytic materials for hydrogenolysis of HMF to produce DMF. The effects of different carriers (e.g., carbon materials, nitrogen‐doped carbon materials, and metal oxides), the bimetallic synergistic effect, and catalyst type on the catalyst activity are systematically introduced. The reaction paths of producing DMF from HMF affected by reaction parameters such as non‐noble metals, hydrogen donors, and temperature are discussed. In addition, potential directions for the large‐scale industrial production and application of DMF are proposed.

How Do the Different Types of Carrier and Drying Techniques Affect the Changes in Physico-Chemical Properties of Powders from Chokeberry Pomace Extracts?

Chokeberry fruit, one of the richest plant sources of bioactives, is processed into different foodstuffs, mainly juice, which generates a considerable amount of by-products. To follow the latest trends in the food industry considering waste management, the study aimed to produce chokeberry pomace extract powders and conduct experimental and chemometric assessment of the effect of different carriers and drying techniques on the physico-chemical properties of such products. The PCA analysis showed that the examined powders were classified into two groups: freeze-dried (variation in case of moisture content, water activity, colour, and browning index) and vacuum-dried (bulk density). No clear pattern was observed for the physical properties of carrier added products. The sum of polyphenolics (phenolic acids, anthocyanins and flavonols) ranged from 3.3–22.7 g/100 g dry matter. Drying techniques had a stronger effect on the polyphenols profile than the type of carrier. Hydroxymethyl-L-furfural formation was enhanced by inulin addition during high-temperature treatment. Overall, the addition of maltodextrin and trehalose mixture for freeze drying and vacuum drying at 90 °C caused the highest retention of polyphenolics and the lowest formation of hydroxymethyl-L-furfural; however, an individual and comprehensive approach is required when the obtainment of high-quality chokeberry powders is expected.

Effect of Different Carriers on In Vitro and In Vivo Drug Release Behavior of Aceclofenac Proniosomes.

Improved bioavailability of Aceclofenac (ACE) may be achieved through proniosomes, which are considered as one of the most effective drug delivery systems and are expected to represent a valuable approach for the development of better oral dosage form as compared to the existing product. However, the carrier in this system plays a vital role in controlling the drug release and modulating drug dissolution. Accordingly, a comparative study on different carriers can give a clear idea about the selection of carriers to prepare ACE proniosomes. This study aims to evaluate the role of maltodextrin, glucose, and mannitol as carriers for in vitro and in vivo performance of Aceclofenac (ACE) proniosomes. Three formulations of proniosomes were prepared by the slurry method using the 100 mg ACE, 500 mg span 60, 250 mg cholesterol with 1300mg of different carriers, i.e., glucose (FN1), maltodextrin (FN2), and mannitol (FN3). In vitro drug release studies were conducted by the USP paddle method, while in vivo studies were performed in albino rats. Pure ACE was used as a reference in all the tests. Lastly, the results were analyzed using the High-Pressure Liquid Chromatography (HPLC) method, and data were evaluated using further kinetic and statistical tools. No significant differences (p > 0.05) in entrapment efficiency (%EE) of FN1, FN2, and FN3 (82 ± 0.5%, 84 ± 0.66%, and 84 ± 0.34% respectively) were observed and formulations were used for further in vitro and in vivo evaluations. During in vitro drug release studies, the dissolved drug was found to be 42% for the pure drug, while 70%, 17%, and 30% for FN1, FN2, and FN3, respectively, at 15 min. After 24 hrs, the pure drug showed a maximum of 50% release while 94%, 80%, and 79% drug release were observed after 24 hr for FN1, FN2, and FN3, respectively. The in vivo study conducted on albino rats showed a higher Cmax and AUC of FN1 and FN2 in comparison with the pure ACE. Moreover, the relative oral bioavailability of proniosomes with maltodextrin and glucose as carriers compared to the pure drug was 183% and 112%, respectively. Mannitol- based formulation exhibited low bioavailability (53.7%) that may be attributed to its osmotic behavior. These findings confirm that a carrier plays a significant role in determining in vitro and in vivo performance of proniosomes and careful selection of carrier is an important aspect of proniosomes optimization.

Effect of different carriers on microstructure and physical characteristics of spray dried apple juice concentrate.

Adhesion is the most important factor in product loss in the spray drying of syrups and juices. The main solution to reduce adhesion is using drying aids. The aim of this study was to evaluate effect of maltodextrin (MD) and gum Arabic as drying aids, and pectin and whey protein concentrate (WPC) as complementary drying aid on the powder yield, physical, functional and microstructural properties of spray dried apple juice concentrate. The studied variables and composition of the carriers were used. The inlet air temperature, atomizer rotational speed, feed flow rate, feed temperature and atomizer pressure were kept constant at 160°C, 18,000rpm, 15ml/min, 25 ± 1°C and 4.2 ± 0.1bar, respectively. The results of powder production yield indicated that WPC was more effective than pectin as complementary drying aid. The bulk and tapped density of powders significantly decreased with an increase in WPC ratio. Moisture content, solubility, wettability, hygroscopicity and color parameters of the powders were also influenced by the carriers` type and their combinations. The microstructure of spray dried powders showed various particle sizes with spherical and irregular shapes (with shrinkages and dents on the surface). Taking into account all the parameters, 10% WPC in combination with MD was used which showed the best results in the economic production of powder with the highest yield (60.85%) and appropriate physical, flowability and functionality properties.

Encapsulation of platinum nanoparticles into a series of zirconium-based metal-organic frameworks: Effect of the carrier structures on electrocatalytic performances of composites

Investigations of the effects of different carriers on electrocatalytic properties of materials are important for heterogeneous systems. Here, we describe the development of composites based on platinum nanoparticles (Pt NPs) incorporated into three Zr-based MOFs, namely, UiO-66, UiO-67 and UiO-68. Three kinds of Zr-MOFs are composed of inorganic Zr6(μ3-O)4(μ3-OH)4 bricks connected through dicarboxylic ligands of different lengths. The surface morphology and microstructure of Pt@UiO-66/67/68 hybrid materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and N2 adsorption-desorption measurements. Hydrazine (N2H4) is chosen as probe molecule to evaluate the electrocatalytic properties of materials due to their rich oxidation process. Cyclic voltammetry (CV) and chronoamperometry (CA) have been used to investigate the electrocatalytic properties of as-fabricated sensors for electrochemical oxidation of N2H4. These studies reveal that N2H4 shows different oxidation mechanisms and electrocatalytic performances at Pt@UiO-66/67/68 modified electrodes. Under the optimal conditions, Pt@UiO-66-2 composite exhibits the best electro-oxidation properties for N2H4. These findings may induce an awareness of the effect of the MOFs carrier structures on the electrochemical performances of composites.

Effect of carrier types and compositions on the production yield, microstructure and physical characteristics of spray dried sour cherry juice concentrate

In this study, the effect of different carriers including maltodextrin (MD), gum arabic (GA) and whey protein concentrate (WPC) and their combination on the production yield, moisture content, bulk and tapped density, solubility, wettability, flowability indexes (Hausner ratio, compressibility, angle of repose), hygroscopicity and deliquescence process, color index and microstructure of spray dried sour cherry juice concentrate was investigated. The results showed increased powder production yield with a mixture of MD and GA (40:10 weight ratio). Use of 5% WPC in combination with the GA and MD increased powder production yield from 45.66 to 55.66% and 42.23 to 52.86%, respectively. Bulk density, tapped density, solubility and wettability significantly decreased with increasing concentration of WPC. Also, the use of 30% WPC in combination with the MD or GA increased particle size substantially. The surface morphology of the particles (with a smooth, shrunk and dented surfaces) was affected by feed composition.

Effects of different carriers on biogas production and microbial community structure during anaerobic digestion of cassava ethanol wastewater

ABSTRACTIn this study, an anaerobic bioreactor (AB) with no added fillers (ABWF), a packed-bed bioreactor with a porous ceramic filler (ABCF), and another packed-bed bioreactor filled with graphite felt (ABGF) were established for anaerobic digestion of cassava ethanol wastewater. The results showed that ABCF exhibited excellent wastewater treatment performance in a stable process that was superior to ABWF and ABGF, with the following characteristics: a high chemical oxygen demand removal efficiency of 98.06% and maximum biogas production of 3200 mL/d at a total reactor volume of 3.46 L. Illumina MiSeq sequencing analysis revealed that differences existed among the microbial communities of the three ABs that were in accordance with the operational characteristics. The ABCF system displayed maximum bacterial diversity, whereas the ABWF system exhibited moderate richness and the ABGF system possessed the lowest species richness. The ABCF system was more stable than the ABWF and ABGF systems during anaerobic digestion of cassava ethanol wastewater. Different functional microbial communities that are responsible for the degradation of certain compounds were also identified in the ABCF and ABGF systems. Our results demonstrate that ceramic materials should be considered an appropriate support for the immobilization of cells.

3DEEM spectroscopy analysis to assess the EPS composition in different carriers in HMBR systems.

A hybrid membrane bioreactor (HMBR) with biological band carriers (Reactor A) and an HMBR with suspended honeycomb carriers (Reactor B) were conducted in parallel to investigate the effects of different carriers on extracellular polymeric substances (EPS). Composition and concentration of EPS were examined by three-dimensional excitation-emission matrix (3DEEM) fluorescence spectra and parallel factor analysis (PARAFAC). 3DEEM spectra demonstrated that the main organic substances of the EPS in two reactors were protein-like, humic acid-like and fulvic acid-like substances. The fluorescence intensity (FI) indicated that the protein-like composition was dominant in EPS, and its intensity in reactor B was stronger than that in A (392.94 > 250.25). Results of the FI identified from the 3DEEM by PARAFAC showed that the EPS in two reactors included two humic acid-like compositions C1 (230, 320/406 nm), C2 (250, 360/440 nm) and one protein-like C4 (230, 280/340 nm), while C3 was fulvic acid-like (220/429 nm) and protein-like (230/357 nm) in reactor A and B, respectively. The proportion and FI of protein-like substances in reactor B were higher than that in A. Consequently, it was concluded that reactor A could control the membrane fouling effectively, compared with reactor B.

The effects of different carriers on removal performance and membrane fouling by HMBR in treating sewage with low carbon-to-nitrogen ratio

A hybrid membrane bioreactor (HMBR) with biological-band carriers (reactor A) and a HMBR with suspended-honeycomb carriers (reactor B) were used for treatment of sewage with low carbon-to-nitrogen ratio (3–5). The pollutant removal performance and membrane fouling in HMBRs was investigated under different hydraulic retention times (HRT) (5h and 9h). The results demonstrated that both HMBRs can be effective for the removal of chemical oxygen demand (COD), NH3-N and total nitrogen (TN). The rate of TN removal in reactor A was higher than that in B. Moreover, it was found reactor A was more advantageous for the degradation of biodegradable organic matter than that of B. The biomass in reactors was characterized by mixed liquor adherent solids (MLAS), particle size distributions, mixed liquor suspended solids (MLSS) and concentration of extracellular polymeric substance (EPS). The results showed that MLAS content and particle size distribution in reactor A were higher than in B, whereas concentrations of MLSS and EPS exhibited the opposite trend. When systems were run under different HRTs, the increased rate of trans-membrane pressure (TMP) in reactor A was slower than that in B. Therefore, reactor A was considered superior to reactor B in pollutant removal and controlling membrane fouling.

Assessing release kinetics and dissolution of spray-dried Roselle (Hibiscus sabdariffa L.) extract encapsulated with different carrier agents

The aim of this study was to investigate the effect of different carriers (maltodextrin, pectin, gelatin, carboxymethyl cellulose, whey protein, carrageenan and gum arabic) on the release kinetics and dissolution of Roselle's extract obtained through a spray drying process. Aqueous solutions at different concentrations of carrier and extract were prepared. The particles obtained exhibited nearly mono-modal or bimodal size distribution, indicating two predominant sizes. The frequency distribution of the mean size of the powders behaved, significantly, like a normal distribution. Throughout the dissolution test, all the particles obtained followed a Weibull-First Order kinetic model. Pectin retained the highest amount of polyphenols after the drying process (98.20 mg GAE/100 mg GAE of roselle concentrate) and released the highest amount of phenolic compounds (79.48 mg GAE/100 mg GAE in the particles) during a longer time. Pectin particles obtained (9 μm as mean size) were significantly homogeneous (93.45 g/100 g powder), being the most suitable carrier of Roselle's phenolic compounds compared to the other carriers used. Estimated dissolution times, by means of the dissolution equation proposed, were compared to experimental results and proved to be more reliable than the regularly used observation method.

Effect of different carriers and operating parameters on degradation of flax wastewater by fluidized-bed Fenton process.

This investigation evaluates the effectiveness of a fluidized-bed Fenton process in treating flax wastewater. Flax wastewater was taken from a paper-making factory in a secondary sedimentation tank effluent of a paper-making factory in Hebei. The performance of three carriers (SiO2, Al2O3, Fe2O3) used in the reactor was compared, and the effects of different operational conditions, and Fenton reagent concentrations were studied. Experimental results indicated that SiO2 was the most appropriate carrier in the system. The dose of Fe2+ and H2O2 was a significant operating factor in the degradation progress. The bed expansion was considered to be another factor influencing the treatment effect. Under the appropriate conditions (300 mg/L Fe2+, 600 mg/L H2O2, and 74.07 g/L SiO2 as the carrier, at pH=3, 50% bed expansion), the highest removal rate of total organic carbon (TOC) and color was 89% and 94%, respectively. The article also discussed the process of the colority removal of flax wastewater and the kinetics of TOC removal.