HA Concentration Research Articles

The rate and evenness of the substitutions on hyaluronan grafted by dodecanoic acid influenced by the mixed-solvent composition

In this work, low molecular weight (17 kDa) hyaluronan was modified by dodecanoyl substituents. The activation of dodecanoic acid was mediated by benzoyl chloride towards the preparation of a mixed anhydride, which reacts in a second step with HA in water mixed with an organic solvent. The effect of the cosolvent was studied and showed an even distribution of substituents and higher reaction rate in water: 1,4-dioxane compared to water:tert-butanol where substituents occupy adjacent positions. The chemical characterization of the prepared derivatives was elucidated by NMR, FTIR spectroscopy, thermal analyses, and gas chromatography, while the distribution of substituents was evaluated by enzymatic degradation. Molecular-dynamics simulations reveal opposite solvent separations around HA and dodecanoyl chains, that is stronger in water:tert-butanol solution. The resulting incompatibility of solvation-shells of the two entities repels the reaction intermediates from the HA chain and drives them towards the already bound substituents, explaining the observed differences in the distribution evenness. Thus, the influence of the solvent on the reaction selectivity is observed by shielding reactive sites around HA. Therefore, a control of the distribution of the substituents was obtained by defining the concentration of HA and used cosolvent.

Formulation development and evaluation of lidocaine hydrochloride loaded in chitosan-pectin-hyaluronic acid polyelectrolyte complex for dry socket treatment

The main purpose of this study was to assess a lidocaine hydrochloride-loaded chitosan-pectin-hyaluronic polyelectrolyte complex for rapid onset and sustained release in dry socket wound treatment. Nine formulations (LCs) of lidocaine hydrochloride (LH) loaded into a chitosan–pectin–hyaluronic polyelectrolyte complex (PEC) were assessed using full factorial design (two factors × three levels). The formulations ranged between 4 and 10% w/w LH and 0.5–1.5% w/w HA. The following physicochemical properties of LCs were characterized: size, zeta potential, % entrapment efficiency, viscosity, mucoadhesiveness, % drug release, morphology, storage stability, and cytotoxicity. The particle size, zeta potential, % EE, viscosity, and % mucoadhesion increased with increasing LH and HA concentrations. Rapid release of LH followed a zero-order model, and a steady-state percentage of the drug was released over 4 h. LCs were found to be non-cytotoxic compared to LH solution. LH loaded into PEC demonstrated appropriate characteristics—including suitable rate of release—and fit a zero-order model. Furthermore, it was not cytotoxic and showed good stability in a high-HA formula, making it a promising candidate for future topical oral formulations.

Formation of toxic iodinated by-products during the oxidation process of iohexol by catalytic ozonation in water

The formation of iodinated by-products during the chemical oxidation process for organic compounds contaminated water has gained increasing attention. Iodinated by-products are more genotoxic, cytotoxic and mutagenic than those of chlorine and bromine analogs. It was reported that the oxidation process of iodinated X-ray contrast media (ICM) could generate iodinated by-products. This study investigated the generation of iodinated by-products during catalytic ozonation of iohexol (one of wide detected ICM). The formation of iodoform (IF) and monoiodoacetic acid (MIAA), and the degradation kinetics of iohexol were compared in different oxidation systems. The effect of various factors, including the iohexol concentration, ozone concentration, HA concentration and solution pH on iodinated by-products generation was evaluated. Additionally, the fate of iodine was investigated by the mass balance calculation. The generated concentrations of I-THMs species with one iodide atom were far higher than those of species with more iodine atoms in the catalytic system at the coexistence of Cl− and Br−. The generation of I-THMs in actual water was relatively low and the normalized value of I-THMs/DOC (μg/mg) had no significant difference. The formation mechanism of high molecular weight iodine-containing by-products included cleavage of the side chain, H-abstraction, substitution iodine for chlorine or bromine and amide oxidation.

Возможность прогнозирования развития фиброза и цирроза при аутоиммунных заболеваниях печени у детей с помощью прямых биомаркеров

Materials and Methods. The study included 80 patients aged 5 to 17 years with chronic autoimmune hepatic disorders. Patients underwent marginal liver excision with laparoscopic control, then the morphology of biopsy samples was examined, HF was determined using METAVIR scale, and ELISA was used to assess blood C-I and HA concentrations. Study Results. Regressive coefficients demonstrated that reduction in C-I concentration by 1 ng/mL increases the odds of HC by 0.983 times, while HA increase by 1 ng/mL results in 1.032-fold increase in the odds of HC. Moreover, increase in HA concentration by 1 ng/mL raises the odds of marked HF or HC by 1.036 times. The resulting regression models are statistically significant (p < 0.001 in both cases). Conclusion. We found statistically significant differences in serum concentration of C-I and HA at various hepatic fibrosis stages in children and developed four predicative models; three of them have satisfactory sensitivity and specificity to predict marked fibrosis and cirrhosis depending on biomarker concentration. Keywords: hyaluronic acid, type I collagen, hepatic cirrhosis, hepatic fibrosis, children.

Study on the treatment of sudden cadmium pollution in surface water by a polymer enhanced ultrafiltration process.

The removal of cadmium(ii) pollution in surface water by a polymer enhanced ultrafiltration (PEUF) process was investigated. Three water soluble polymers, chitosan (CTS), polyvinyl alcohol (PVA) and polyacrylate sodium (PAAS), were selected for this study. Of the three polymers, PAAS had strong interactions with Cd2+, and the PEUF achieved a high removal of Cd2+; therefore, PAAS was used as a complexing agent for the simulated cadmium pollution experiment. Experiments were performed as a function of the aqueous pH, polymer/Cd2+ ratio (P/M), ionic strength and humic acid. Under optimum experimental conditions, the Cd2+ removal rate reached 100%. pH was the main factor affecting removal of Cd2+, which decreased to 60% at a pH of 4. The Cd2+ removal was found to decrease as NaCl and HA were added. The analysis showed that the mechanism of NaCl could be a compressed electric double layer, while the mechanism of HA and H+ was competitive complexation. Finally, UF membrane fouling, the dissociation of PAAS–Cd and the regeneration of PAAS were investigated. The results showed that the higher P/M was, the lower the pH, the higher the HA concentration, and the more serious the UF membrane fouling were. The dissociation rate of PAAS–Cd reached 99.8% at a pH of 2.5. When the P/M was 5, the removal rate of Cd reached 99.6% with the addition of 20% new PAAS in the regenerate. This result showed that the PEUF process could be a promising method for removing Cd pollution in surface water.

Transformation of bromophenols by aqueous chlorination and exploration of main reaction mechanisms

Bromophenols (BPs) are ubiquitous phenolic contaminants and typical halogenated disinfection byproducts (DBPs) that are commonly detected in aquatic environments. The transformation of 2,4-dibromophenol (2,4-DBP) during chlorination process was fully explored in this research. It was found that active chlorine can react with 2,4-DBP effectively in a wide pH range of 5.0–11.0, with an apparent second-order rate constant (kapp) varying from 0.8 M−1 s−1 to 110.3 M−1 s−1. The addition of 5 mM ammonium ions almost completely suppressed the reaction via competitive consumption of free chlorine. With the concentration of HA increasing from 1.0 to 10.0 mg L−1, the inhibition on the degradation of 2,4-DBP increased from 8.7% to 63.4%. By contrast, bromide ions at a concentration of 5 mM accelerated the process by about 4 times, due to the formation of hypobromous acid. On the basis of the eleven products (with eight nominal masses) identified by LC-TOF-MS, electrophilic substitution reactions and single-electron transfer reactions were mainly involved in the chlorination process. The concentration of primary chlorine-substituted products was about 4 times that of the dimer products, demonstrating that electrophilic substitution reaction was predominant during chlorination of 2,4-DBP. Density functional theory (DFT) based calculations revealed that HOCl is the dominant active oxidizing species for elimination of 2,4-DBP and coupling reaction occurs more easily at para and ortho position of hydroxyl group in the phenolic moiety. These findings could provide some new insights into the environmental fate of bromophenols during chlorine disinfection of water and wastewaters.

Factors influencing pre-injection aspiration for hyaluronic acid fillers: A systematic literature review and meta-analysis.

Pre-injection aspiration of hyaluronic acid filler is a well-recognized yet controversial safety technique. Many consider aspiration to be an important safety measure to prevent inadvertent intravascular filler injection. To assess factors influencing pre-injection aspiration by understanding the relationship between aspiration time and a range of product, needle, and procedural characteristics. We conducted a systematic review and meta-analysis of data, adopting the preferred reporting items for systematic reviews and metaanalyses guidelines. Our literature search identified four articles presenting data on variables associated with aspiration time for different HA filler brands. Statistical models pooling data from the four articles suggest a robust association between aspiration time and a filler's elastic modulus (G'), drop weight (cohesivity), and cross-sectional area of the needle lumen. However, there is insufficient evidence to confirm a robust association between aspiration time and HA concentration, viscous modulus (G″), needle length, and pullback volume. A deeper understanding of the relationship between product, needle, and procedural characteristics, and aspiration time can provide a sound base for discussing the role of pre-injection negative aspiration as a safety measure. The understanding of the effect of various factors on preinjection aspiration would further benefit from studies under clinical conditions.

Effect of nanohydroxyapatite on surface mineralization in acid-etched dentinal tubules and adsorption of lead ions

To study the effect of nanohydroxyapatite (nHA) for promoting surface mineralization of demineralized dentin discs and adsorption of lead ions in simulated sewage water. Sixty dentin disks were prepared from freshly extracted teeth with intact crown (including 30 premolars and 30 molars) and treated with 10% citric acid for 2 min to simulate dentinal tubules with dentin hypersensitivity. The etched dentin discs were brushed with distilled water, 0.2 g HA or 0.2 g nHA for 2 min twice a day for 7 consecutive days, after which scanning electron microscopy (SEM) was performed and calcium and phosphorus contents in the dentin discs were detected using EDS. Lead ion adsorption capacities of HA and nHA were tested by mixing 1 mL serial concentrations of HA and nHA suspensions with 50 mL lead ion solutions (1.0 mg/L). After 24 h, the residual lead ion concentration in the supernatant was measured using ICP to calculate lead ion adsorption rate and adsorption capacity of the materials. SEM showed a smooth surface and empty dentin tubules in the acid- etched dentin dics. The dentin dics treated with HA were covered with masses of particles that loosely attached to the surface, and the diameter of the dentin tubules was reduced. In nHA group, the dentin discs showed a fine and homogeneous surface clogging with a tight attachment, and the dentin tubule diameter was obviously reduced. Daily brushing with HA and nHA, especially the latter, significantly increased calcium and phosphorus contents on the surface of the dentin dics (P < 0.000). In lead ion adsorption experiment, the lead ion adsorption rate of HA decreased as its concentration increased with the highest adsorption rate of 83.01%; the adsorption rate of nHA increased with its concentration until the adsorption equilibrium was reached, and its highest adsorption rate was 98.79%. A good liner relationship was found between the adsorption ability and concentration of HA. Compared with HA, nHA has a better capacity for surface mineralization of acid-etched dentin discs and also a better ability of lead ion adsorption.

Wavelet-Based Noise Removal from Raman Signal to Study PLD Coated Forsterite–Hydroxyapatite Thin Film on Stainless Steel 316l Substrate

Raman spectroscopy is proposed here for the study of forsterite–hydroxyapatite (FS–HA) composite coating on a stainless-steel substrate. However, in order to analyze the Raman spectrum accurately, noise and background removal is always required. A comparative study has been done for the correction of background. The waveletbased denoising of the signal was done using level 6 decomposition with sym4 wavelet and the thresholding method used was soft thresholding. In the present work, the effectiveness of the wavelet-based denoising method has been compared with Savitsky–Golay smoothing, quadratic regression, and the low-pass filter method. It is found that the wavelet-based denoising method works better as compared to other methods as it is able to smooth the signal and to increase the SNR while maintaining the peak intensity undistorted. Peaks are calculated for the different composition of the FS–HA composite. The variation of peak location in the processed Raman spectra suggests that the variation in concentration of FS and HA in the coating can be studied by using Raman spectroscopy.

Unraveling influence of metal species on norfloxacin removal by mesoporous metallic silicon adsorbent.

Metal-modified adsorbent had appreciable adsorption capacity and fast rate toward norfloxacin (NOR), but limited studies focused on the influence of metal species on adsorbents' performance. In this study, Fe and Cu were chosen to be loaded on mesoporous silicon SBA-15 for absorbing NOR and investigating the key function of metal species. An obvious synergy effect was found between active species and supporter. A high adsorption capacity (44.8mgg-1 for Fe/SBA-15 and 78.3mgg-1 for Cu/SBA-15) and short equilibration time (< 2h) were obtained. NOR adsorptions on two processes were described well by pseudo-second-order kinetics, particle diffusion equation, and Langmuir isotherm. The adsorption processes were spontaneous, but NOR adsorption on Cu/SBA-15 was endothermic while its adsorption on Fe/SBA-15 was exothermic. HA had dual effect on the adsorption efficiency, with a promotion at low HA concentration but an inhibition at high concentration. NOR removal increased first and then decreased with pH ascension from 3 to 9 for both Fe/SBA-15 and Cu/SBA-15, achieving maximum at pH = 7. Comparative characterizations and experiments suggested that NOR adsorption processes were dominated by electrostatic interactions, n-π EDA interactions, hydrogen bonds, and surface complex. The greater n-π EDA and complex efficiency of Cu with NOR resulted in the superior performance of Cu/SBA-15. Graphical abstract.

Stability and characterization of mixture of three particle system containing ZnO-CuO nanoparticles and clay

The aim of this study was to understand heteroaggregation of mixture of ZnO and CuO nanoparticles (NPs) with clay, for the first time as per the authors' knowledge. Aggregation studies of mixture of ZnO and CuO nanoparticles with clay was done (ionic strength =5 mM; pH 7; nanoparticles concentration = 0.1 mg/L, 1 mg/L, 10 mg/L; Clay concentration = 1, 10, and 100 mg/L and HA concentration = 0.1,1, and 10 mg/L as total organic carbon). Critical coagulation concentration (CCC) and attachment efficiency values of suspensions with ZnO: CuO ratio = 0.1, 1, 10 were also determined. Aggregation and liquid portions of mixture suspension at equal mass ratio were characterized for size, zeta potential (ZP), metal and ion contents, pH and conductivity. Results indicated that CCC was found to be 120.7 mM for ZnO: CuO ratio 10 and 1144 mM for ZnO: CuO ratio 1. Values of attachment efficiency were obtained to be 0.9 and 0.8 for these two ZnO:CuO ratio. At natural water ionic strength (IS) condition, aggregate rate constant of mixture of particles ranged from 0.281 to 8.63 nm/min for 10 mg/L NP concentration. Aggregation in suspension containing mixture of particles was found to be affected by NP concentration, clay concentration, and humic acid (p < 0.05). During a 1-h aggregation study, 2.67 mg Cu metal/g aggregate and 0.38 mg Zn/g aggregate were found in aggregates of 5 mM suspension. Overall, this study provided information on aggregation characterization of mixture of metal oxide nanoparticles (ZnO and CuO) in HA and clay presence, which is useful in understanding aggregation formation and in characterizing exposure dose for environmental risk assessment. More detailed information on a three -particle system with natural colloids is required for predicting their fate in aquatic system and defining risk.

Removal of humic acid from aqueous solution by Fe3O4@L-arginine magnetic nanoparticle: kinetic and equilibrium studies

ABSTRACT Natural organic materials, principally humic acids cause serious problems in water treatment plants due to combination with chlorine and the formation of carcinogenic disinfection by-products. In the present study, the Fe3O4@L-arginine magnetic nanoparticle was synthesised and used to adsorbhumic acid (HA) from the aqueous solution. Fe3O4@L-arginine nanoparticles were prepared withthe co-precipitation method and characterised by FE-SEM, FTIR, XRD, and zeta potential analysis. The effect of different parameters on the HA removal by Fe3O4@L-arginine was investigated. The results showed that by increasing the adsorbent dose, contact time and temperature, the efficiency of HA removal increased, but by increasing theinitial concentration of HA, ionic strength, and pH, the efficiency of HA elimination decreased. Under optimal conditions, the highest HA removal efficiency in 0.5 g/L and 2 g/L adsorbent doses was found to be 67.23% and 96.4%, respectively. Also, the study of isotherm and kinetic of adsorption showed that the adsorption of HA on Fe3O4@L-arginine followed Langmuir isotherm and pseudo-second-order kinetic.Adsorption experiments demonstrated that Fe3O4@L-arginine as an effective and reusable adsorbent has a good capacity for the removal of HA from aqueous solution.

Reduced NOM triggered rapid Cr(VI) reduction and formation of NOM-Cr(III) colloids in anoxic environments

Natural organic matter (NOM) can influence the toxicity and speciation of chromium (Cr) in subsurface through redox reactions and complexation. Under anoxic conditions, NOM can be reduced by microorganisms or geochemical reductants, and the reduced NOM (NOMred) represents a large reservoir of organic matter observed in anoxic sediments and water. While the current body of work has established the kinetic of Cr(VI) reduction by oxidized NOM (NOMox) under oxic conditions, much less is known about the rates and mechanisms of Cr(VI) reduction triggered by NOMred under anoxic conditions and the colloidal properties of the reaction products. This study provided new information regarding the NOMred-mediated Cr(VI) reduction and colloidal stability of reduced Cr(III) particles over a wide range of environmentally relevant anoxic conditions. We show that under dark anoxic conditions reduced humic acid (HAred) moieties (e.g., quinone) can quickly reduce Cr(VI) to Cr(III), and the reduced Cr(III) can subsequently complex with carboxyl groups of HA leading to the formation of stable HA-Cr(III) colloids. Rates of Cr(VI) reduction by HAred are 3–4 orders of magnitude higher than those by oxidized HA (HAox) due primarily to the higher reducing capacity of HAred. The stable HA-Cr(III) colloids are formed across a range of HA concentrations (8–150 mg C/L) and pH conditions (6–10) with hydrodynamic diameter in the range of 210–240 nm. Aberration-corrected scanning transmission electron microscopy (Cs-STEM) and X-ray photoelectron spectroscopy (XPS) confirmed that the particles are composed of HA-Cr(III). The high colloidal stability of HA-Cr(III) particles could be attributed to the enhanced electrosteric stabilization effect from free and adsorbed HA, which decreased particle aggregation. However, the presence of divalent cations (Ca2+ and Mg2+) promoted particle aggregation at pH 6. These new findings are valuable for our fundamental understanding of the fate and transport of Cr in organic-rich anoxic environments, which also have substantial implications for the development and optimization of subsurface Cr sequestration technology.

Optimizing of Coating Layers Parameters of (Nano Hydroxyapatite/TiO2 NPs) on Nitinol SMAs by Electrophoretic Deposition

This study aims to obtain the optimal variable for depositing (HA, TiO2 and Composite) Nanomaterial on NiTi SMAs. Taguchi approach (with L9 array) was used to obtain the optimal conditions for coating produced by Electrophoretic deposition (EPD) techniques. The deposition process was done in different conditions (voltage, time, concentration and degree of grinding). Voltages were used (20, 40 and 60) volts, the time is (2, 4 and 6) min, the degree of the surface roughness (180, 500 and 1200) µm while the concentration of HA and TiO2 are (2, 4, and 6) g/L for each one. Chitosan (biopolymer) was used as binder material to the ceramic materials. The result of the Taguchi approach detected that the best conditions of HA layer are (20 V, 4 min, 2%C and the degree of surface 180), TiO2 is (20 V, 4 min, 4%C and the degree of surface 180) and composite layer is (60 V, 4 min, 4%C and the degree of surface 180). Solutions stability was measured by utilizing Zeta potential tests; which clarified good stability for all of them. Optical microscope and scanning electron microscopy were used to characterize and study the surface of the coating layers. The bonding adhesion was measured using a tape test in order to evaluate the adhesion bonding between the coating and substrate. It found that the percentage of removal coating area for samples were (8.8%for HA, 4.9% for TiO2 and 6.9% of the composite layer.

Effect of hydroxyapatite filler concentration on mechanical properties of poly (methyl methacrylate) denture base

Poly (methyl methacrylate) or PMMA is an acrylic material has been used widely as a denture base material. The denture base is subjected to various stresses during the function, these include tensile and flexural stresses. The current study was aimed to experimentally evaluate the effect of different filler concentrations on physical and mechanical characteristics of PMMA/HA composite. PMMA reinforced with different ratios (i.e. 0, 5, 10, and 15 wt%) of silane treated HA were prepared to study the effect of HA concentration on the mechanical properties of acrylic denture base material. Tensile, flexural and fracture toughness tests were conducted to evaluate the mechanical performance. The fracture surfaces of all the composites were studied using scanning electron microscopy. The hardness of the composite was investigated using Vickers hardness. Independent t-test was also conducted to evaluate the significant difference in the values measured as a function of different filler loading. Data analyses showed a significant improvement (P 0.05) was detected in the tensile and flexural strength as function of HA incorporation. A small increment of only 1.63% and 3% in the tensile and flexural strength respectively, was achieved at very low filler loading i.e. 5 wt%. An improvement of only 7.8% in the surface hardness was observed for PMMA loaded with 15 wt% of HA.

Dynamic thiol/disulphide homeostasis as indicator of oxidative stress in automotive workers

Purpose: To examine thiol-disulphide homeostasis auto painters.Materials and methods: A total of 115 male workers, including 60 auto painters workers and 55 reference group, of the painting and assembly line units respectively, were included in the study. Thiol-disulphide parameters and ischaemia-modified albumin (IMA) of groups were determined. Urinary hippuric acid, (HA) phenol, hexanedione, trichloroacetic acid, arsenic and blood lead and manganese were analysed.Results: The median urinary HA level was significantly higher in auto painters when compared to the reference group [(2461 (1212) vs. 520 (513) µgr/L), (p < 0.001)] . The mean disulphide level [19.7 (4.3) vs 0.15.1(4.1) μmol/L, (p < 0.001)], the disulphide/native thiol ratio [4.72 (1.47) vs. 3.13 (1.21, (p < 0.001)] and the disulphide/total thiol ratio [4.31 (1.23) vs. 2.94 (1.06), (p < 0.001)] were higher in auto painters when compared to the reference group. There was a statistically significant positive correlation between urinary HA and disulphide concentrations (r = 0.536 and p < 0.001), disulphide/native thiol ratio (r = 0.564 and p < 0.001) and the disulphide/total thiol ratio (r = 0.564 and p < 0.001) and IMA (r = 0.396 and p < 0.001).Conclusion: The results presented in this study showed that oxidative stress can be associated with occupational exposure to toluene denoted by alteration of thiol disulphide homeostasis and ischaemia-modified albumin levels.

Increasing Concentration of Sinovial: Effect on Cartilage Protection in a Rabbit ACLT Model.

This study aimed to test the hypothesis that administration of increasing doses of Sinovial (hyaluronic acid [HA]), would exhibit a dose-dependent effect on the prevention of cartilage degradation, without local and systemic toxicity. Twenty-seven adult rabbits were subjected to anterior cruciate ligament transection (ACLT). Two Sinovial products containing HA concentrations of 1.6% and 2.4% were used as active treatment, and 0.9% saline was used as control and injected intra-articularly 7 days post ACLT. Radiographs were taken prior to surgery, at injection and sacrifice times. After euthanasia, 8 weeks postsurgery, knee joints were observed macroscopically using India ink staining with OARSI (Osteoarthritis Research Society International) scoring and histologically using modified Mankin scoring. The synovial membranes were analyzed using Cake classification. No intraoperative complications were observed. One week postinjection, 4 animals in the HA 2.4% group developed subcutaneous nodules that disappeared spontaneously. No inflammation of the synovial membrane was ever observed. The control group exhibited the maximum uptake of India ink 2.22 ± 0.14. HA groups exhibited a dose-dependent (P = 0.02) reduction in India ink uptake: 1.75 ± 0.17 for HA 1.6% and 1.58 ± 0.14 for HA 2.4%. The most marked dose-dependent effect of this study was a reduction of modified Mankin score for HA groups, with the 2.4% treatment achieving a statistically significant improvement as compared with the control group (7.19 ± 0.85 for saline, 4.65 ± 0.66 for HA 1.6%, and 3.53 ± 0.59 for HA 2.4%; P = 0.005). A dose-dependent protective effect on cartilage was observed after injection of both HA solutions.

Bacterial cellulose/hyaluronic acid nanocomposites production through co-culturing Gluconacetobacter hansenii and Lactococcus lactis under different initial pH values of fermentation media

Providing additives into the culture media is a traditional method to manufacture bacterial cellulose (BC) based nanocomposites. This study employed a novel fermentation process, which is to co-culture Gluconacetobacter hansenii (G. hansenii) with genetically modified Lactococcus lactis (L. lactis) under static conditions, to synthesize BC/HA (hyaluronic acid) nanocomposites. The HA concentration produced by L. lactis and the dry weight of BC/HA during co-culture were regulated by the initial pH values of culture media. The incorporation of HA into the cellulose network increased the crystal sizes when the initial pH values were at 7.0, 6.2, and 5.5. The strain at break was also increased while Young’s modulus was decreased when comparing BC/HA to pure BC produced under the initial pH values of culture media at 7.0 and 6.2. When the initial pH value was 4.0, the HA concentration in the culture media exhibited the lowest level observed, which was 20.4 ± 2.3 mg/L. The BC/HA composite synthesized under this condition exhibited an improved Young’s modulus of 5029 ± 1743 MPa from 2705 ± 656 MPa associated with the pure BC. The FESEM images showed that the presence of HA dramatically changed the distribution of ribbon width in BC/HA compared to that of pure BC. The BC/HA produced by co-culture fermentation didn’t need to add extra and expensive HA during production and could be used in biomedical applications such as wound dressing and tissue engineering.

Application of amine-functioned Fe3O4 nanoparticles with HPEI for effective humic acid removal from aqueous solution: Modeling and optimization

Humic acids are one type of natural organic matter and precursors of chloro organic compounds that cause a major problematic issue for water treatment plants. In the present study, Hyperbranched polyethylenimine (HPEI) was grafted onto Fe3O4 nanoparticles for HA adsorption from aqueous solution. Fe3O4@HPEI nanoparticles were characterized via TEM, SEM, FTIR, XRD, VSM, and BET analysis. The effects of various operational parameters including initial HA concentration, pH, adsorbent dose, contact time and ionic strength on the HA removal were assessed. According to the obtained statistical model, the optimal condition was acquired at the initial HA concentration 79 mg/L, adsorbent dose 0.128 g/L, pH 3 and contact time 29 min, which up to 97.27% HA were adsorbed by Fe3O4@HPEI that was close to the predicted result by the model (95.6%) that confirmed the validity of the selected model. The adsorption data were fitted to the pseudo-second-order kinetic and Freundlich isotherm. Thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic. The fabricated Fe3O4@HPEI nanoparticles could be repeatedly utilized as a suitable adsorbent to remove HA from the aqueous environment.

The removal of 2,4,6-trichlorophenol in water by Ni/Fe nanoparticles

In this paper, the removal of 2,4,6-trichlorophenol (2,4,6-TCP) by synthesized Ni/Fe nanoparticles were investigated. At the same time, the factors, such as the dosage of Ni/Fe, Ni content in Ni/Fe nanoparticles, sulfate ion, HA, coexisting substances in water which affected the removal of 2,4,6-TCP by synthesized Ni/Fe nanoparticles were also investigated. Under the experimental conditions, the removal efficiency of 2,4,6-TCP by Ni/Fe nanoparticles in water was about 72% for 2 h. The dosage of Ni/Fe, Ni content in Ni/Fe nanoparticles, and Fe3+all promoted the dechlorination reaction of 2,4,6-TCP by Ni/Fe nanoparticles. Sulfate, oxalic acid and citric acid played an inhibitory role on the removal of 2,4,6-TCP by Ni/Fe nanoparticles in water. Fe2+had no obvious affect to the removal of 2,4,6-TCP by Ni/Fe nanoparticles in water. In addition, low initial HA concentration was favorable for the removal of 2,4,6-TCP by Ni/Fe nanoparticles, while high concentrations of HA played an inhibitory role.