Preparation and Mechanical Properties of UV-Curable Epoxy Acrylate/Modified Aramid Nanofiber Nanocomposite Films

In order to enhance the mechanical properties of UV-curable epoxy acrylate (EA)-based coatings, 3-(trimethoxysilyl)propyl methacrylate modified aramid nanofibers (T-ANFs) were synthesized and used as nanofillers to prepare EA/T-ANF nanocomposite films. The morphology of T-ANFs was characterized by transmission electron microscopy. The chemical structure of T-ANFs was analyzed via infrared spectroscopy, confirming successful grafting of methyl methacryloyloxy groups onto the surface of aramid nanofibers (ANFs). Real-time infrared spectroscopy was employed to investigate the influence of ANFs and T-ANFs on the photopolymerization kinetics of the EA film. The results revealed that the addition of ANFs and T-ANFs led to a decrease in the photopolymerization rate during the initial stage but had little impact on the final double bond conversion, with all samples exhibiting a conversion rate of over 83%. The incorporation of ANFs improved the tensile strength of the films while significantly reducing their Young's modulus. In contrast, the addition of T-ANFs led to a substantial increase in both tensile stress and Young's modulus of the films. For instance, the tensile strength and Young's modulus of the 0.1 wt% of T-ANF film increased by 52.7% and 41.6%, respectively, compared to the pure EA film. To further study the dispersion morphology and reinforcement mechanism, the cross-sectional morphology of the films was characterized by scanning electron microscopy.

[Analysis of conventional echocardiographic features in apical hypertrophic cardiomyopathy patients complicated with left ventricular apical aneurysm]

Objective: To explore the basic characteristics of conventional echocardiography of apical hypertrophic cardiomyopathy (ApHCM) patients complicating with left ventricular apical aneurysm (LVAA). Methods: This is a retrospective study. Patients who underwent echocardiography and cardiac magnetic resonance (CMR) and were diagnosed with ApHCM complicated with LVAA by CMR at Fuwai Hospital, Chinese Academy of Medical Sciences from August 2012 to July 2017 were enrolled. According to whether LVAA was detected by echocardiography, the enrolled patients were divided into two groups: LVAA detected by echocardiography group and LVAA not detected by echocardiography group. Clinical data of the two groups were compared to analyze the causes of missed diagnosis by echocardiography. Results: A total of 21 patients were included, of whom 67.0% (14/21) were males, aged (56.1±16.5) years. Patients with chest discomfort accounted for 81.0% (17/21), palpitation 38.1% (8/21), syncope 14.3% (3/21). ECG showed that 21 (100%) patients had ST-T changes and 18 (85.7%) had deep T-wave invertion. Echocardiography revealed ApHCM in 17 cases (81.0%) and LVAA in 7 cases (33.3%). The mean left ventricular apical aneurysm diameter was 33.0 (18.0, 37.0) mm, and left ventricular ejection fraction was (66.5±6.6) %, and left ventricular apex thickness was (21.0±6.3) mm. Left ventricular outflow tract obstruction was presented in 4 cases and middle left ventricular obstruction in 10 cases. The mean left ventricular apical aneurysm diameter of LVAA detected by echocardiography was greater than that of LVAA not detected by echocardiography (25.0 (18.0, 28.0) mm vs. 16.0 (12.3, 21.0) mm, P=0.006). Conclusions: Conventional echocardiography examination has certain limitations in the diagnosis of ApHCM. Smaller LVAA complicated with ApHCM is likely to be unrecognized by echocardiography. Clinicians should improve their understanding of this disease.

Conductive Aramid Fibers from Electroless Silver Plating of Crosslinked HPAMAM-Modified PPTA: Preparation and Properties

Conductive aramid (PPTA) fibers are highly needed for making flexible conductive materials, antistatic materials, and electromagnetic shielding materials. In this work, silver-plated conductive PPTA fibers with high conductivity and excellent mechanical properties were prepared by the electroless plating of PPTA fibers modified with crosslinked hyperbranched polyamide-amine (HPAMAM). The crosslinked HPAMAM creates a stable interface between the PPTA fibers and the silver plating. The morphology and physicochemical properties of the modified and the silver-plated fibers were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Three epoxy crosslinking agents with different chain lengths were used to crosslink HPAMAM, and the effects of HPAMAM concentration, crosslinking agent dosage, and crosslinking time on the resistance of the fibers were studied. The long chain crosslinking agent appears to be beneficial to silver plating. The lowest resistance (0.067 Ω/cm) was attained when HPAMAM was modified by diethylene glycol diglycidyl ether (1:1 molar ratio), and 20 g/L HPAMAM was used to modify the PPTA fibers. The tensile strength of the original PPTA fibers decreased by only 3% or less after silver plating.

Facile Synthesis of Cross-linked Hyperbranched Polyamidoamines Dendrimers for Efficient Hg(Ⅱ) Removal From Water

Dendrimers as commonly used metal ions adsorption materials have the advantages of good adsorption performance and high reuse rate, but the high cost limits its extensive use. Compared with dendrimers, hyperbranched dendrimers have similar physical and chemical properties and are more economical. Therefore, hyperbranched dendrimers are more suitable for industrial large-scale adsorption. The hyperbranched polyamidoamine (HPAMAM) gels were prepared by cross-linking hyperbranched polyamidoamine (HPAMAM-ECH-x and HPAMAM-EGDE-x) with different amounts of epichlorohydrin (ECH) and ethylene glycol diglycidyl ether (EGDE), respectively. The as-synthesized adsorbents were characterized by FT-IR, SEM and XPS. The prepared adsorbents were used to adsorb Hg(Ⅱ) in aqueous solution, and the effects of solution pH, contact time, temperature and initial concentration of metal ion on the adsorption capacity were investigated. The effect of solution pH indicated that the optimum condition to Hg(Ⅱ) removing was at pH 5.0. The adsorption kinetic curves of the two kinds of materials were in accordance with the pseudo-second-order model. For the HPAMAM-ECH samples, the adsorption thermodynamic curves fitted the Langmuir model, while for the HPAMAM-EGDE samples, both Langmuir and Freundlich equations fitted well. The maximum adsorption capacity of HPAMAM-ECH-3 obtained from Langmuir model toward Hg(Ⅱ) was 3.36 mmol/g at pH 5.0 and 35°C.

Applications of microbial co-cultures in polyketides production

Polyketides are a large group of natural biomolecules that are normally produced by bacteria, fungi and plants. These molecules have clinical importance due to their anti-cancer, anti-microbial, anti-oxidant and anti-inflammatory properties. Polyketides are biosynthesized from units of acyl-CoA by different polyketide synthases (PKSs), which display wide diversity of functional domains and mechanisms of action between fungi and bacteria. Co-culture of different micro-organisms can produce novel products distinctive from those produced during single cultures. This study compared the new polyketides produced in such co-culture systems and discusses aspects of the cultivation systems, product structures and identification techniques. Current results indicate that the formation of new polyketides may be the result of activation of previously silent PKSs genes induced during co-culture. This review indicated a potential way to produce pure therapeutic polyketides by microbial fermentation and a potential way to develop functional foods and agricultural products using co-co-culture of different micro-organisms. It also pointed out a new perspective for studies on the process of functional foods, especially those involving multiple micro-organisms.

Aramid Nanomaterials of Various Morphologies: Preparation and Mechanical Property Enhancement

Aramid nanofibers (ANFs) are a novel type of promising nanoscale building blocks for high-performance nanocomposites. Conventionally, ANFs are used to composite with polymers containing polar groups such as –OH and –NH₂ since those polymers can interact with the amide groups in ANFs through polar-polar interaction such as hydrogen bonding. In this study, ANFs were derivatized with non-polar alkyl groups including ethyl, octyl and dodecyl groups and used as a performance-enhancing additive to polyvinyl chloride (PVC) with weak polarity. Interestingly, it was observed that the morphologies of the resulting alkyl-derivatized aramid nanomaterials (R-ANMs) varied significantly including nanofibers, nanobranches, nanosheets, and nanospheres, all of which depended on the degree of substitution (DS) and the chain length of the alkyl group. As an additive, R-ANMs improved the Young's modulus, toughness and yield strength of the PVC films. This study proves the concept that ANFs can be used to composite weakly polar or non-polar polymers.

Fabrication of Triethylenetetramine Terminal Hyperbranched Dendrimer-Like Polymer Modified Silica Gel and Its Prominent Recovery Toward Au (III)

To further increase the quantity and density of functional groups on adsorbent, terminal triethylenetetramine hyperbranched dendrimer-like polymer modified silica-gel (SG-TETA and SG-TETA2) was synthesized. The hyperbranched dendrimer-like polymer was successfully introduced onto silica gel and new cavities were formed, which was demonstrated by FTIR, SEM, and BET. The highest adsorption capacities of SG-TETA and SG-TETA2 obtained from Langmuir model toward Au(III) were 2.11, and 2.27 mmol g⁻¹, respectively, indicating that SG-TETA2 possessing more functional groups had a better adsorption ability. Moreover, the adsorbents combined with Au(III) ion through chelation and electrostatic attraction mechanism, after which reduction reactions for Au(III) ion loaded on adsorbents proceeded. SG-TETA2 had better adsorption selectivity than SG-TETA in removing Au(III) in Au-existed ion solution systems. SG-TETA2 had higher overall adsorption capacities compared to silica-gel-based hyperbranched polymers functionalized by diethylenetriamine. Therefore, the effective recovery makes SG-TETA2 a practical adsorbent in removing Au(III) ion from e-wastes and industrial effluents with much prospect.

[Efficacy and peripheral immunity analysis of allogeneic natural killer cells therapy in patients with hepatocellular carcinoma]

OBJECTIVE

To evaluate the safety and efficacy of allogeneic natural killer (NK) cells in the treatment of primary hepatocellular carcinoma (HCC), and to elucidate the mechanism of NK cells therapy.

METHODS

Twenty-one patients with primary HCC treated with allogeneic NK cells at the Fifth Medical Center of the PLA General Hospital were followed up for 1 year. Peripheral blood mononuclear cells (PBMCs) were isolated from patient-related donors and cultured in vitro for 15 days and infused to the patients in two consecutive days. Clinical data and laboratory data were collected and analyzed, including survival, clinical features, imaging changes, hematology, immunology, and biochemical indicators to evaluate the safety and efficacy of allogeneic NK cell therapy. The changes of peripheral blood lymphocyte subsets after treatment were also analyzed to explore the possible anti-tumor mechanisms.

RESULTS

(1) Of the 21 patients with primary HCC, 11 patients were treated once, 5 patients were treated twice, and 5 patients were treated 3 times. After allogeneic NK cells infusion, 10 patients had fever, 1 patient had slight hepatalgia and 1 patient had slight headache, no other adverse events occurred including acute and chronic graft-versus-host disease (GVHD). They resolved spontaneously within 8 hours without other treatment. (2) The total disease control rate was 76.2% during one-year follow-up. Among them, the patients with Barcelona clinic liver cancer (BCLC) stage A had a disease control rate of 100%, stable disease (SD) in 10 cases; BCLC stage B patients had a disease control rate of 60%, partial response (PR) in 1 case, and SD 2 in cases; BCLC stage C patients had a disease control rate of 50%, complete response (CR) in 1 case, and 2 cases of PR. (3) The frequencies of NK cells and CD8+ T cells in peripheral blood were significantly lower than that before at 24 hours after treatment, and the frequencies of CD4+ T cells and CD4/CD8 were significantly higher than the baseline.

CONCLUSION

Allogeneic NK cells have good safety and efficacy in the treatment of primary HCC. The anti-tumor effect of the allogeneic NK cells may play an important role in the activation of the patient's natural immune system and delay disease progression, suggesting that allogeneic NK cells combined with sorafenib may be a very effective treatment for advanced HCC, and further large-sample multicenter randomized controlled clinical trials are needed to validate this result.

Amino- and Thiol- Polysilsesquioxane Simultaneously Coating on Poly(p-Phenylenetherephthal Amide) Fibers: Bifunctional Adsorbents for Hg(II)

A double reagents simultaneous functionalization (DRSF) was used to prepare porous polysilsesquioxane with NH₂ and SH bifunctional groups (PAMPSQ) coated poly(p-phenylenetherephthal amide) (PPTA) fibers adsorbents (PPTA-AM), via in situ condensations with aminopropyltriethoxysilane (APTES) and mercaptopropyltriethoxysilane (MPTES). The PAMPSQ coated on the PPTA surface was in the form of nanoparticles and its morphology varied with the proportion of the reactants. The PAMPSQ exhibited loose open meso- or macroporous features. The functional groups utilization of PAMPSQ was much higher than those of polysilsesquioxane on the mono-functional adsorbents with thiol or amino groups. The selective adsorption of PPTA-AM adsorbents for Hg(II) in binary component metal ion systems indicated their potential application in environmental remediation. The adsorption mechanism of Hg(II) onto PPTA-AM was proposed.

A randomised controlled trial of stepwise sputum collection to increase yields of confirmed tuberculosis

<sec> <title>SETTING</title> The proportion of bacteriologically confirmed tuberculosis (TB) in China has decreased far below the worldwide average. </sec> <sec> <title>OBJECTIVE</title> To investigate whether stepwise measures to ensure sputum quality can improve the rate of bacteriologically confirmed TB. </sec> <sec> <title>DESIGN</title> We enrolled 980 adults with suspected TB from three counties in China during 2017 for this multicentre randomised controlled trial. Half the participants (n = 490) were randomly assigned to intervention groups that received instructions by a study nurse, and sputum induction, if necessary. In the remaining 490 patients, sputum samples were collected without observation. The primary outcome was the proportion of patients detected as bacteriologically positive on smear, culture or molecular assays (EasyNAT or Xpert). </sec> <sec> <title>RESULTS</title> Bacteriological confirmation rates were significantly higher in the intervention than in the control group: overall (159/490 [32%] vs. 122/490 [25%]; P = 0.009); confirmation using smear (17% vs. 11%; P = 0.010); confirmation using culture (28% vs. 21%; P = 0.021); and confirmation using molecular assays (27% vs. 18%; P = 0.001). Most of the improvement was in patients who received instruction alone, while improvement was greatest in younger patients (adjusted odds ratio 1.27, 95%CI 1.05-1.53 per 10 years). </sec> <sec> <title>CONCLUSIONS</title> If implemented effectively in resource-limited primary care clinics, our simple stepwise procedure combining instruction and sputum induction could increase the proportion of bacteriologically confirmed TB significantly. </sec>.

[Endoscopic selective lateral neck dissection via a chest-breast approach for papillary thyroid carcinoma: preliminary experience in 20 cases]

Objective:To explore the feasibility of endoscopic selective lateral neck dissection(SLND) via a chest-breast approach.Method:We retrospectively reviewed 20 patients who underwent endoscopic total thyroidectomy along with SLND, between January 2017 and May 2018. Result: All the 20 patients underwent total thyroidectomy, central lymph nodes dissection and selective lateral lymph nodes dissection with endoscopic surgery via chest-breast approach. In this study, lymphatic leakage, transient voice hoarseness, internal jugular vein injury and external jugular vein injury were repectively found in one patient, and 4 patients suffered from transient parathyroid hypofunction, without other serious complications.Conclusion: Endoscopic lymph node dissection including levels Ⅱ,Ⅲ and Ⅳ is feasible. It has good cosmetic effect, and haven't serious adverse events.

Exploring multiple functions of diarylsemipinacol linked to the saturated ethylene–propylene elastomer: from the dynamic covalent networks to tailoring its macroscopic performance

Through the multiple functions of diarylsemipinacol, we prepared a mechanically robust and healable EPM with shape memory properties, by integrating self-associating ureidopyrimidinone (UPy) into the dynamic covalent networks.

Removal of Cd(II) and Fe(III) from DMSO by silica gel supported PAMAM dendrimers: Equilibrium, thermodynamics, kinetics and mechanism

A series of silica gel supported amino-terminated PAMAM dendrimers (SG-G1.0 - SG-G3.0) were used for the removal of Cd(II) and Fe(III) from dimethylsulfoxide (DMSO). Various parameters that influence adsorption behaviors including temperature, contact time, and initial metal ion concentration were studied. The adsorption mechanism was revealed by combining the results of experiment and density functional theory (DFT) calculation. It indicates that the adsorption capacities for Cd(II) and Fe(III) are largest among the metal ions tested. The adsorption capacity of SG-G1.0 - SG-3.0 for Cd(II) and Fe(III) follows the order of SG-G2.0 > SG-3.0 > SG-G1.0. The adsorption isotherm shows the adsorption capacities for both metal ions increases with raising the temperature and initial metal ion concentration. The adsorption isotherm is consistent with Langmuir model and the adsorption process is dominated by chemical adsorption mechanism. Thermodynamic parameters indicates that the adsorption for both Cd(II) and Fe(III) is spontaneous and endothermic. Kinetic adsorption indicates that the adsorption equilibrium times for Cd(II) and Fe(III) is about 200 and 350 min, respectively, which can be described by a pseudo-second-order model and controlled by film diffusion process. FTIR analysis and theoretical calculation revealed that the carbonyl O atoms, secondary amine N atoms, and primary amine N atoms are the primary factor responsible for PAMAM adsorption by forming tetra- and penta-coordinated chelates with metal ions.

Pore structure control factors of polyamine-bridged polysilsesquioxanes by sol-gel method and their structure-adsorption properties for Au(III)

A series of bridged polysilsesquioxane (BPS) materials was synthesized by the sol-gel method from 3-chloropropyl trimethoxysilane, diethylenetriamine (DETA) or ethylenediamine. Tetraethyl orthosilicate (TEOS) and/or one of the two templates, hexadecyl trimethyl ammonium bromide (CTAB) or P123, were used in the co-condensation process to construct some of the porous adsorbents. The adsorption of Au(III) was the highest for samples without TEOS, especially for the DETA series with CTAB template. This study elucidates the synthesis and applications of BPS materials.

[A comparison of fine needle nonaspiration cytology versus fine needle aspiration for thyroid nodules: a Meta-analysis]

Objective:To evaluate the differences of smear quality and diagnostic accuracy between thyroid nodules and fine needle nonaspiration cytology (FNNAC) and fine needle aspiration cytology (FNAC).Method:Databases were used to search the literature on FNNAC and FNAC. All statistical analyses were performed using Review Manager 5.3 Software.Result:A total of 10 studies were included in the study. Meta-analysis showed no significant difference in FNNAC and FNAC between low, middle and high quality smears. There was no significant difference in diagnostic accuracy.Conclusion:There were no difference in obtaining the smear quality and diagnostic accuracy, the person doing the piercing can freely choose which way according to the habit.

[Diagnostic accuracy and safety of US-guided core needle biopsy versus fine needle aspiration biopsy of thyroid nodules: a Meta analysis]

Objective:To evaluate the efficacy and safety of core needle biopsy (CNB) and fine neon needle aspiration biopsy (FNAB) in the diagnosis of thyroid nodules.Method:The CNKI, Wanfang database, China Biomedical Literature Database (CBM), PubMed, Cochrane Library, EMBASE, Web of Science database (the deadline of February 2017) were used to search the literature on CNB and FNABCNB. Two reviewers independently screened the literature according to the inclusion and exclusion criteria, extracted the data and evaluated the quality of the literature, and used RevMan 5.3 software for Meta analysis.Result:The accuracy of the CNB group was higher than that of the FNAB group(RR= 1.14, 95%CI: 1.06-1.22, P< 0.01). Meta analysis showed that the accuracy of CNB group compared with FNAB group was statistically significant the difference was statistically significant. There was no significant difference between the two groups (RR= 0.92, 95%CI:0.67-1.25, P> 0.05).Conclusion:CNB is safe and feasible in the diagnosis of thyroid nodules under the condition of mastery of puncture technique.

Hg(II) adsorption using amidoximated porous acrylonitrile/itaconic copolymers prepared by suspended emulsion polymerization

Initially, porous acrylonitrile/itaconic acid copolymers (AN/IA) were prepared by suspended emulsion polymerization. Successively, the cyano groups in AN/IA copolymers were converted to amidoxime (AO) groups by the reaction with hydroxylamine hydrochloride. The structures of the AN/IA and amidoximated AN/IA (AO AN/IA) were characterized by infrared spectroscopy, scanning electron microscopy, and porous structural analysis. The adsorption properties of AO AN/IA for Hg(II) were investigated. The results show that AO AN/IA has mesopores and macropores, and surface area of 11.71 m(2) g(-1). It was found that AO AN/IA has higher affinity for Hg(II), with the maximum adsorption capacity of 84.25 mg g(-1). The AO AN/IA also can effectively remove Hg(II) from different binary metal ion mixture systems. Furthermore, the adsorption kinetics and thermodynamics were studied in detail. The adsorption equilibrium can quickly be achieved in 4 h determined by an adsorption kinetics study. The adsorption process is found to belong to the second-order model, and can be described by the Freundlich model.

Design of an effective bifunctional catalyst organotriphosphonic acid-functionalized ferric alginate (ATMP-FA) and optimization by Box-Behnken model for biodiesel esterification synthesis of oleic acid over ATMP-FA

Biodiesel production has become an intense research area because of rapidly depleting energy reserves and increasing petroleum prices together with environmental concerns. This paper focused on the optimization of the catalytic performance in the esterification reaction of oleic acid for biodiesel production over the bifunctional catalyst organotriphosphonic acid-functionalized ferric alginate ATMP-FA. The reaction parameters including catalyst amount, ethanol to oleic acid molar ratio and reaction temperature have been optimized by response surface methodology (RSM) using the Box-Behnken model. It was found that the reaction temperature was the most significant factor, and the best conversion ratio of oleic acid could reach 93.17% under the reaction conditions with 9.53% of catalyst amount and 8.62:1 of ethanol to oleic acid molar ratio at 91.0 °C. The research results show that two catalytic species could work cooperatively to promote the esterification reaction, and the bifunctional ATMP-FA is a potential catalyst for biodiesel production.

Synthesis of silica gel supported salicylaldehyde modified PAMAM dendrimers for the effective removal of Hg(II) from aqueous solution

A series of silica gel supported salicylaldehyde modified PAMAM dendrimers (SiO2-G0-SA ∼ SiO2-G2.0-SA) were synthesized and their structures were characterized by FTIR, XRD, SEM, TGA, and porous structure analysis. The feasibility of these adsorbents for the removal of Hg(II) from aqueous solution was first described and the adsorption mechanism was proposed. The adsorption was found to depend on solution pH, the generation number of salicylaldehyde modified PAMAM dendrimers, contact time, temperature, and initial concentration. Results showed that the optimal pH was about 6 and the adsorption capacity increased with the increasing of generation number. Density functional theory (DFT) method was used to investigate the coordination geometries and the chelating mechanism. Adsorption kinetics was found to follow the pseudo-second-order model with film diffusion process as rate controlling step. Adsorption isotherms revealed that adsorption capacities increased with the increasing of temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models were employed to analyze the equilibrium data. The adsorption can be well described by Langmuir isotherm model and took place by chemical mechanism. The thermodynamics properties indicated the adsorption processes were spontaneous and endothermic nature. The maximum adsorption capacity of SiO2-G0-SA, SiO2-G1.0-SA, and SiO2-G2.0-SA were 0.91, 1.52, and 1.81 mmol g(-1), respectively. The considerable higher adsorption capacity compared with other adsorbents indicates SiO2-G0-SA ∼ SiO2-G2.0-SA are favorable and useful for the uptake of Hg (II), and can be potentially used as promising adsorbents for the effective removal of Hg(II) from aqueous solution.

Utilization of rice husks modified by organomultiphosphonic acids as low-cost biosorbents for enhanced adsorption of heavy metal ions

Novel biosorbent materials (RH-2 and RH-3) obtained from agricultural waste materials rice husks (RH-1) were successfully developed through fast and facile esterification reactions with hydroxylethylidenediphosphonic acid and nitrilotrimethylenetriphosphonic acid, respectively. The present paper reported the feasibility of using RH-1, RH-2 and RH-3 for removal of heavy metals from simulated wastewater, the results revealed that the adsorption property of functionalized rice husks with organotriphosphonic acid RH-3 for Au(III) was very excellent, especially for gold ions. The combined effect of initial solution pH, RH-3 dosage and initial Au(III) concentration was investigated using response surface methodology (RSM), the results showed that initial Au(III) concentration exerted stronger influence on Au(III) uptake than initial pH and biomass dosage. The analysis of variance (ANOVA) of the quadratic model demonstrated that the model was highly significant, and under the optimum process conditions, the maximum adsorption capacity could reach 3.25 ± 0.07 mmol/g that is higher than other reported adsorbents.

Efficient bifunctional catalyst lipase/organophosphonic acid-functionalized silica for biodiesel synthesis by esterification of oleic acid with ethanol

An efficient bifunctional catalyst lipase/organophosphonic acid-functionalized silica (SG-T-P-LS) has been successfully developed, and biodiesel production of fatty acid ethyl ester (FAEE) from free fatty acid (FFA) oleic acid with short-chain alcohol ethanol catalyzed by SG-T-P-LS was investigated. The process optimization using response surface methodology (RSM) was performed and the interactions between the operational variables were elucidated, and it was found that the molar ratio of alcohol to acid was the most significant factor. The optimum values for maximum conversion ratio can be obtained by using a Box-Behnken center-united design, and the conversion ratio could reach 89.94 ± 0.42% under the conditions that ethanol/acid molar ratio was 1.05:1 and SG-T-P-LS to FFA weight ratio was 14.9 wt.% at 28.6°C. The research results show that SG-T-P and LS-20 could work cooperatively to promote the esterification reaction, and the bifunctional catalyst SG-T-P-LS is a potential catalyst for biodiesel production.

Adsorption Kinetics of Au(III) Ions on a Novel Chelating Resin Silica-Gel Functionalized by an Amino Organophosphonic Acid

The adsorption kinetics of Au(III) on a novel chelating resin namely silica gel functionalized by an amino phosphonic acid (denoted as SiO2–EDA–APA) were studied. The results showed that SiO2–EDA–APA could reach its saturation adsorption capacity within 4 h, and its excellent adsorption capacity for Au(III) was 234.61 mg g −1 when the initial solution concentration was 2.0 mmol L −1 at 35°C. The adsorption kinetics of the as-synthesized hybrid adsorbent for Au(III) at different temperatures can be modelled closely by a pseudo second-order rate equation. The thermodynamic parameters of adsorption, Δ G, Δ H and Δ S were – 18.89 kJ mol −1, 19.82 kJ mol −1, and 125.74 J K−1 mol −1, respectively. It can be concluded that the adsorption of Au(III) on SiO2–EDA–APA is a spontaneous, endotherminc process controlled by film diffusion, which results in its higher adsorption capacity at higher temperatures.

Adsorption of Pb(II) from aqueous solution by silica-gel supported hyperbranched polyamidoamine dendrimers

The adsorption properties of silica-gel supported hyperbranched polyamidoamine dendrimers (SiO(2)-G0-SiO(2)-G4.0) have been investigated by batch method. The effect of pH of the solution, contact time, initial Pb(II) ion concentration, temperature and coexisting metal ions have been demonstrated. The results indicated that the optimum pH value was 5. Adsorption kinetics was found to follow the pseudo-second-order model and controlled by film diffusion. The adsorption isotherms were fitted by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. Langmuir isotherm model was found to be more suitable to describe the equilibrium data, suggesting the uptake of Pb(II) ions by monolayer adsorption. From D-R isotherm model, the calculated mean free energy E demonstrated the adsorption processes occurred by chemical ion-exchange mechanism. FTIR analysis revealed that amine groups were mainly responsible for the adsorption of Pb(II) by amino-terminated adsorbents, while CO of ester groups also participated in the adsorption process of ester-terminated ones. The adsorbents can selectively adsorb Pb(II) from binary ion systems in the presence of Mn(II), Cu(II), Co(II), and Ni(II). Based on the results, it is concluded that SiO(2)-G0-SiO(2)-G4.0 had great potential for the removal of Pb(II) from aqueous solution.

Uptake of gold (III) from waste gold solution onto biomass-based adsorbents organophosphonic acid functionalized spent buckwheat hulls

Novel biomass-based adsorbents organophosphonic acid functionalized spent buckwheat hulls (OPA-BH) with 60 mesh were successfully employed to adsorb Au(III) ions from simulated wastewater. The adsorption kinetics and isotherms both in unary ion system and in ternary ions system were investigated, and the applicability of the Langmuir, Freundlich and extended Langmuir isotherm models has been tested for the equilibrium. The process optimization was also conducted by using response surface methodology (RSM), and the maximum adsorption capacities reached 2.84 ± 0.01 mmol/g under the optimum process conditions. Furthermore, the regeneration capacities of OPA-BH were investigated by using the eluent solutions of 0.0-5.0% thiourea in 0.1 mmol/L HCl, and the results showed that the adsorption capabilities for OPA-BH were ranged between 0.77 mmol/g and 0.85 mmol/g after three cycles of adsorption-desorption processes. The research results showed that OPA-BH was favorable and useful for gold adsorption, and the high adsorption capacity and good reproducibility make it a good promising material for the precious metal uptake.

Biosorption of heavy metal ions onto agricultural residues buckwheat hulls functionalized with 1-hydroxylethylidenediphosphonic acid

Novel biosorbent materials obtained from agricultural residues buckwheat hulls (BH) were successfully developed through functionalization with 1-hydroxylethylidenediphosphonic acid (HEDP), and they were characterized. This paper reports the feasibility of using HEDP-BH for removal of heavy metals from stimulated wastewater, the experimental results revealed that the adsorption property of functionalized buckwheat hulls with 120 mesh 120-HEDP-BH for Au(III) was very excellent, and the monolayer maximum adsorption capacity for Au(III) calculated from the Langmuir isotherm models was up to 450.45 mg/g at 35 °C. The combined effect of initial solution pH, 120-HEDP-BH dosage, and initial Au(III) concentration was investigated using response surface methodology (RSM), and the result showed that biomass dosage exerted a stronger influence on Au(III) uptake than those of initial pH and initial Au(III) concentration. Analysis of variance (ANOVA) of the quadratic model demonstrated that the model was highly significant. Moreover, investigation on the adsorption selectivity showed that 120-HEDP-BH displayed strong affinity for gold in aqueous solutions and even exhibited 100% selectivity for Au(III) ions in the presence of Zn(II) and Co(II). Regeneration capacities of 120-HEDP-BH were studied using the eluent solutions of 0.0-5.0% thiourea in 0.1 mmol/L HCl, and it was found that the adsorption capability remains high after several cycles of adsorption-desorption process.

Kinetic and Thermodynamic Studies of Adsorption of Heavy Metal Ions from Fuel Ethanol

The cleaning treatment of fuel ethanol plays an important role in its effective utilisation, and adsorption is one useful process to remove heavy metal ions from fuel ethanol solutions. In this work, a novel silica gel adsorbent functionalised with an aminophosphonic acid (denoted as SG-T-P) was developed, characterised, and used to remove heavy metal ions from fuel ethanol solutions. The adsorption properties of SG-T-P for Hg(II), Cu(II), Mn(II), Co(II), Zn(II), Ni(II), Fe(III) and Cd(II) in ethanol solutions were studied, revealing that SG-T-P had an excellent adsorption capacity for Hg(II). Furthermore, the kinetic data indicated that the adsorption process was governed by film diffusion and followed a pseudo-second-order rate model for SG-T-P. The thermodynamic parameters Δ G, Δ H and Δ S were – 6.80kJ mol−1 (35°C), 55.49 kJ mol−1, and 203.92 J K −1 mol −1, respectively. Thus, SG-T-P is effective and useful for the removal of Hg(II) from fuel ethanol solutions, and its good adsorption ability make it a promising candidate material for mercury uptake.