Conversion of a renewable bio-resource to a functional composite material: Product design,comprehensive characterization and adsorption of 2,4-D herbicide

Based on the opinion of “utilizing waste resources to treat waste”, a sustainable resource waste was transformed into a useful and functional material by a comprehensive experimental setup. A high surface area lentil processing waste-based activated carbon was synthesized by microwave-assisted K₂CO₃ chemical activation and then successfully converted into a ferrospinel composite. The ferrospinel composite was characterized with BET, FTIR, XRD, XPS, FE-SEM, EDX mapping, Raman and VSM techniques and the detailed characterization analysis confirmed the successful formation of the ferrospinel composite. It was also applied as an effective adsorbent material in the treatment of 2,4-dichlorphenoxyacetic acid herbicide bearing wastewater. The pseudo-second order model better defined the kinetic pathway of the adsorption while the isothermal data indicated the best suitability to Langmuir model. The maximum adsorption capacity of the ferrospinel composite towards 2,4-dichlorophenoxyacetic acid was 400 mg/g at 45 °C. Thermodynamic studies showed the favorability and spontaneity of the adsorption process.     

Adsorptive removal of lead from aqueous solutions by amine–functionalized magMCM-41 as a low–cost nanocomposite prepared from rice husk: Modeling and optimization by response surface methodology

Amorphous silica that was extracted from rice husk was used to synthesize the magMCM-41 mesoporous silica. This was then functionalized by the APTMS group in order to produce NH₂-magMCM-41 as a novel and low–cost adsorbent. The XRD, VSM, N₂ adsorption–desorption, FT–IR, TGA, SEM and TEM analyses were utilized to characterize the produced materials. In order to optimize the adsorption of the Pb(II) ions, the RSM (response surface methodology) was applied by using the synthesized adsorbent in aqueous solutions. A rotatable CCD (central composite design) was adopted to carry out the experiments and RSM was used to analyze them. Three independent factors namely, initial solution pH (3–7), adsorbent dosage (0.1–2 g L^?1), and initial Pb(II) concentration (15–150 mg L^?1) were used to investigate the removal procedure. According to the obtained results, the initial solution pH of 5.22, adsorbent dosage of 0.1 g L^?1, and initial Pb(II) concentration of 150 mg L^?1 were considered as the optimum conditions with 64.32% removal of Pb(II) and an adsorption capacity of 540.64 mg g^?1. The maximum removal efficiency of Pb(II) ions was found to be 96.76%. The Sips isotherm model represents a better correlation with equilibrium data. It was reported by the kinetic study that data taken from the experiments fitted better to the pseudo–second–order model compared to the pseudo–first–order and intraparticle diffusion models. Finally, according to the thermodynamic study, the removal process strongly depends on temperature, which indicates an exothermic behavior and spontaneous nature of the adsorption.     

高纯度庆大霉素C1a游离碱制备工艺研究

目的 探索用大孔吸附树脂层析法及盐析结晶法精制纯化硫酸依替米星起始物料-庆大霉素C1a成品(HPLC纯度91%~93%)，从而减少由起始物料引入依替米星杂质的水平。方法 以庆大霉素C1a吸附量和庆大霉素C1a纯度为指标，考察大孔吸附树脂纯化庆大霉素C1a的吸附性能和洗脱参数；以盐析后庆大霉素C1a样品纯度和盐析收率为指标，考察盐析工艺最佳温度、溶剂、酸的添加量及酸的种类。结果 获得较优的树脂NM200，获得较优的解析液pH值为2.0和流速0.5BV/h。经过优化后，纯化收率从65%提高至74%。通过盐析结晶条件筛选和优化，确定室温先加溶剂后加硫酸(pH6.5)和甲醇与乙醇1:2的条件较优，优化后获得的庆大霉素C1a纯度达到98.2%，收率大于93%。研究了多种无机酸盐析结晶的情况，发现磷酸、硫酸和碳酸条件下能析出白色固体。结论 通过比较大孔吸附树脂和盐析结晶的纯化连接，组合纯化后获得的庆大霉素C1a游离碱纯度大于99.0%，比纯化前样品提高6%以上，收率大于70%。     

Thermodynamic Estimate of the Number of Solvent Molecules Displaced by a Solute Molecule for Enthalpy-Driven Adsorption: Phenobarbital and Activated Carbons as the Model System

A Modified Crisp Equation, describing the differential Gibbs free energy of the adsorption process, is being proposed, which considers multiple sites available on the surface for adsorption and their relative fractions. The differential Gibbs free energy can be calculated by the van't Hoff Equation, which depends on the affinity constant in the Langmuir-like equation. To consider the number of solvent molecules displaced by a solute molecule in the adsorption process, a new derivative of the Langmuir-like equation is being proposed as well. By comparing the differential Gibbs free energies obtained from the 2 thermodynamic relationships, it can be determined that a phenobarbital molecule displaces 5 water molecules on the activated carbon surface for site-specific adsorption from solution. For the series of experimental conditions studied, including 4 activated carbons, pH effects, temperature effects, and solvent effects, the corrected differential Gibbs free energies using n₁ = 5 for site-specific adsorption are quite consistent between the 2 thermodynamic relationships. The difference between the estimates of the differential Gibbs free energies by the Modified Crisp Equation and the van't Hoff Equation provides a new experimental method to calculate the number of solvent molecules displaced by an adsorbing solute molecule.     

Effect of Architecture of Thermoresponsive Copolymer Brushes on Switching of Their Adsorption Properties

Herein, the effect of architecture of stimuli‐responsive polymer brushes on the switching of colloidal particle adsorption is reported. Thermoresponsive copolymer brushes containing positively charged amino groups are used and investigated how negatively charged colloidal particles electrostatically adsorb onto them. The distribution of charged groups (block or random copolymer architecture) and the conformation of the polymer chains (extended or collapsed state) are varied. It is found that the strongest adsorption is achieved at high fractions of charged groups in the brushes, while the amount of adsorbed particles is independent of the polymer chain conformation; that is, the adsorption of particles cannot be switched. On the contrary to this, the most pronounced switching of adsorption is achieved at low fractions of charged/adhesive groups in the brushes when the adsorption of particles is weak. The lowest fraction of charged/adhesive groups (one group per few polymer chains) can be exclusively achieved by random copolymerization and not by block copolymers. An explanation of the adsorption behavior of colloidal particles on switchable brushes is proposed.     

Immunologic non-inferiority and safety of the investigational pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) 4-dose vial presentation compared to the licensed PHiD-CV 1-dose vial presentation in infants: A phase III randomized study

BackgroundTo support vaccination programs in developing countries, a 4-dose vial presentation of pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) was developed. This study assessed immunologic non-inferiority and safety of the investigational PHiD-CV 4-dose versus licensed 1-dose vial presentation in infants.MethodsIn this phase III, mono-center, observer-blind study in Bangladesh, 6–10-week-old infants were randomized 1:1 to receive PHiD-CV primary vaccination (at ages 6, 10, 18 weeks) and a booster dose (at age 9 months) with a 4-dose vial (with preservative, 4DV group) or 1-dose vial (preservative-free, 1DV group). DTPw-HBV/Hib was (co)-administered per study protocol and polio, measles and rubella vaccines as part of the national immunization program. Non-inferiority of PHiD-CV 4-dose versus 1-dose vial for each vaccine pneumococcal serotype (VT) and vaccine-related serotype 19A in terms of antibody geometric mean concentration (GMC) was assessed (criterion: upper limit of 2-sided 95% confidence interval of antibody GMC ratios [1DV/4DV] <2-fold). Immune responses were measured. Solicited, unsolicited and serious adverse events (AEs) were evaluated.ResultsOf 320 infants (160 per group) vaccinated during the primary vaccination phase, 297 received a booster. Non-inferiority was demonstrated for each VT and 19A. One month post-primary vaccination, for most VT, ≥97.9% of infants in each group had antibody concentrations ≥0.2 μg/mL; for 19A ≥ 80.1% reached this threshold. Pneumococcal antibody responses and opsonophagocytic activity for each VT and 19A were within similar ranges between groups after primary and booster vaccination, as were anti-protein D responses. Booster immune responses were observed in both groups. Reported AEs were within similar ranges for both presentations.ConclusionImmunologic non-inferiority of PHiD-CV 4-dose vial (with preservative) versus PHiD-CV 1-dose vial (preservative-free) was demonstrated. Immune responses and reactogenicity following primary/booster vaccination were within similar ranges for both presentations. PHiD-CV 4-dose vial would help improve access and coverage in resource-limited countries.Clinical Trial Registry: NCT02447432.     

蛋白质在膜表面的吸附特性及蛋白质存在的溶液环境对小檗碱膜透过行为的影响研究

为探索蛋白质在膜表面的吸附特性以及蛋白质存在的溶液环境对小檗碱膜透过行为的影响,以蛋白质、小檗碱为研究对象,配制模拟溶液,通过低场核磁共振技术、静态吸附实验以及膜分离实验探究蛋白质与陶瓷膜、小檗碱之间可能存在的相互作用,以蛋白质静态吸附量、膜过程相对通量、蛋白质截留率、小檗碱透过率及两者的吸附率为评价指标,同时测定膜过程中膜污染阻力分布、过膜前后粒径分布变化及膜表面电镜扫描(SEM),研究蛋白质在陶瓷膜上的吸附特性及对小檗碱膜过程的影响。结果表明,陶瓷膜对蛋白质具有吸附作用,且吸附模型符合Langmuir吸附模型,在模拟溶液的膜分离过程中,蛋白质是引起膜污染的主要因素,但在1 g·L~(-1)蛋白质的浓度下,蛋白质的存在对小檗碱的膜过程没有显著影响。     

Competitive adsorption versus surface complexation as models for the simultaneous adsorption of metal complexes and free ligands

A statistical thermodynamical approach to the study of anion-induced adsorption of Cd(II) from halide solutions is presented. The simultaneous adsorption of metal complex and ligand is introduced in the isotherms by considering two possible mechanisms — competitive adsorption and surface complexation. These isotherms have been tested for the system Cd(II) in KBr at several ionic strengths. The experimental surface excesses of Cd(II) calculated from single-step chronocoulometry can be simulated, giving an explanation for the desorption of the metal complex at positive potentials. Also, the change in ligand adsorption promoted by the adsorption of the metal complex has been calculated. Both approaches lead to the conclusion that the anionic tricoordinate metal complex CdBr₃^? and the tetracoordinate CdBr₄^2? are the absorbed species on the electrode surface, with CdBr₄^2? dominating at higher bromide concentrations.     

金属钛种植体表面蛋白吸附动力学研究

本章应用简单的称重法对等温吸附曲线和吸附动力学曲线进行了粗略的测定，并应用先进的XPS技术对蛋白质在不同pH值下的解吸特性进行研究。发现材料表面的蛋白吸附量随蛋白溶液的浓度的增加和时间的延长而增加，而且在浸泡最初的吸附量增加最快，尤其在前20分钟，吸附几乎就达到了平衡．还发现钛种植体表面的吸附的能力比317L不锈钢的吸附能力强，几乎同时进入吸附的平衡阶段。在体液pH值状态下，钛表面的蛋白吸附量最高，随着pH值向两侧移动，钛表面的蛋白吸附量在下降，而当pH值为25和12时，表面蛋白吸附量降至最小值，pH值继续升高或降低反而表面蛋白的残余量有所升高。     

Vibrational study of adsorbed phosphate ions on rhodium single crystal electrodes

The adsorption of H₂PO₄^? ions was studied on low Miller index rhodium single crystal electrodes by in situ FTIR spectroscopy. It is found that for Rh(1 0 0) and Rh(1 1 0), H₂PO₄^? ions are the major species at low potentials, but at higher potentials, some of the H₂PO₄^? ions undergo a potential induced deprotonation and probably there is a mixture of H₂PO₄^? and HPO₄^2? ions. On Rh(1 1 1) the deprotonation starts at very low potentials and at higher potentials the H₂PO₄^? is fully converted to HPO₄^2?. The behavior of the band center and of the band intensity with the applied potential was also analyzed. It is found that the adsorption increases from 0.08 V vs. a Pd–H₂ electrode up to 0.5 V and then it decreases when the OH starts to be adsorbed.