How preparation and modification parameters affect PB‐PEO polymersome properties in aqueous solution

The effect of formation and modification methods on the physical properties of polymersomes is critical for their use in applications relying on their ability to mimic functional properties of biological membranes. In this study, we compared two formation methods for polymersomes made from polybutadiene‐polyethylene oxide diblock copolymers: detergent‐mediated film rehydration (DFR) and solvent evaporation (SE). DFR‐prepared polymersomes showed a three times higher permeability compared to SE‐prepared polymersomes as revealed by stopped‐flow light scattering. SE‐prepared polymersomes broke down faster to structures <50 nm diameter when processed with extrusion, which was more pronounced at 5 mg mL^?1, compared to 10, 20, and 25 mg mL^?1. Our results indicate that the bilayer of SE‐prepared polymersomes has a lower apparent fluidity. We also investigated the role of n‐octyl‐β‐d ‐glucopyranoside (OG), a detergent typically used for reconstitution of membrane proteins into lipid bilayers. Specifically, we compared dialysis and biobeads for OG removal to investigate the influence of these methods on bilayer conformation and polymer rearrangement following detergent removal. There was no significant difference found between method, temperature, or time within each method. Our findings provide insight on how biocompatible polymersome production affects the physical properties of the resulting polymersomes. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1581–1592     

Heavy Metal Removal from Synthetic Solutions with Magnetic Beads Under Magnetic Field

The aim of this study is to prepare magnetic beads which can be used for the removal of heavy metal ions from synthetic solutions. Magnetic poly(ethylene glycol dimethacrylate‐vinyl imidazole) [m‐poly(EGDMA‐VIM)] beads were produced by suspension polymerization in the presence of magnetite Fe₃O₄ nano‐powder. The specific surface area of the m‐poly(EGDMA‐VIM) beads was found to be 63.1 m²/g with a size range of 150–200 µm in diameter and the swelling ratio was 85%. The average Fe₃O₄ content of the resulting m‐poly(EGDMA‐VIM) beads was 12.4%. The maximum binding capacities of the m‐poly(EGDMA‐VIM) beads were 32.4 mg/g for Cu²⁺, 45.8 mg/g for Zn²⁺, 84.2 mg/g for Cd²⁺and 134.5 mg/g for Pb²⁺. The affinity order on mass basis is Pb²⁺>Cd²⁺>Zn²⁺>Cu²⁺. Equilibrium data agreed well with the Langmuir model. pH significantly affected the binding capacity of the magnetic beads. Binding of heavy metal ions from synthetic wastewater was also studied. The binding capacities were 26.2 mg/g for Cu²⁺, 33.7 mg/g for Zn²⁺, 54.7 mg/g for Cd²⁺ and 108.4 mg/g for Pb²⁺. The magnetic beads could be regenerated up to about 97% by treating with 0.1 M HNO₃. These features make m‐poly(EGDMA‐VIM) beads a potential candidate for support of heavy metal removal under magnetic field.     

Rapid Removal of Organics and Oil Spills from Waters Using Silicone Rubber “Sponges”

We have developed a simple, robust, and efficient technology utilizing cheap and recoverable materials based on commercially available silicone elastomer networks for removing organic solvents and crude oil from waters. Hydrophobic and oleophilic properties of silicone elastomers endow poly(dimethyl siloxane) (PDMS) with the capacity to absorb a large variety of organics, including benzene (B), toluene (T), ethylbenzene (E), and xylene (X), commonly referred to as BTEX, and also crude oils, while at the same time enabling the organic “sponges” to float on waters, which facilitates straightforward handling. We developed a method for generating PDMS particles with variable sizes (ranging from hundreds nanometers to few millimeters) by drop-wise depositing siloxane/cross-linker mixtures into warm water, a process which leads to the cross-linking of the PDMS components. We have tested the capability of the PDMS particles to remove toluene and benzene from water. We also performed similar experiments by utilizing PDMS sheets. In both instances we observed a rapid sorption of the organic phase into PDMS; the amount of absorbed organic solvent depended on the concentration in water and the total mass (volume) of PDMS and did not depend on the geometry of the PDMS “sponge.” In addition, we have examined the uptake of toluene and benzene from toluene/benzene (T/B) mixtures dissolved in water. Our results indicate that the amount of benzene absorbed from the T/B mixtures into PDMS increases relative to the uptake from pure benzene/water solutions. This behavior is associated with toluene acting as a “surfactant” that effectively replaces the more unfavorable PDMS/B contacts with less costly T/B ones. Finally, a simple experiment demonstrates qualitatively that PDMS is also capable of removing crude oils from oil-contaminated waters.     

MgO脱除HCN的动力学研究

研究了MgO在不同温度下对HCN的脱除作用,并用XRD对反应后固相产物进行分析。研究了温度、MgO质量分数、HCN初始体积分数和停留时间等因素对HCN脱除效率的影响,并求出MgO与HCN反应的动力学参数。结果表明,673 K时,MgO已经开始与HCN发生反应,当温度高于873 K时,HCN中气态"N"已转化到固相产物MgCN₂中;HCN脱除效率随温度、MgO质量分数和停留时间的增加呈线性增加,但随HCN初始体积分数增加呈负幂函数的规律下降;MgO与HCN的反应级数α为0.72,表观活化能E为32.2 kJ/mol。     

Cleansing contaminated seawaters using marine cyanobacteria: evaluation of trace metal removal from the medium

The use of microbial biomass in biosorption is already being studied as a potential alternative to (or combined with) conventional processes, where several algae and microorganisms have already shown promising ability to uptake metals. Cyanobacteria (blue-green algae) are widespread organisms, with specific properties, such as high nutrient removal capacity and tolerance to highly variable conditions which make them well-suited for wastewater and remediation purposes. The main aim of this work was to evaluate the use of a marine cyanobacterium LEANCYA 21 (Synechocystis sp.), collected from the Portuguese southern border, for the removal of selected trace metals when in natural seawater culture medium. It was observed, for the first time, that this particular strain is capable of uptaking Pb, Ni and Zn (at nM levels) from seawater solutions using small amounts of biomass. Uptake values for Pb were up to 90% (0.75 mg g^?1 biomass) in 6 h. The specific biosorption curves of Ni and Zn showed that these metals follow a first order kinetics biosorption in batch conditions. Solutions containing multimetals have revealed that Ni uptake is affected by the presence of Pb and Zn. The calculated specific absorption values were high enough to predict a possible application in aquaculture where such low levels of metals may inhibit microalgae growth.     

K/LiCoO2的制备及其同时催化去除碳烟和NOx的性能研究

采用溶液燃烧法和浸渍法制备了铜铁矿结构的钴酸锂(LiCoO2)及其负载K的系列催化剂样品,并通过XRD、NOx-TPD、H2-TPR、程序升温反应等对其进行了结构表征与性能评价.结果表明LiCoO2是一种能有效同时去除碳烟(PM)和NOx的催化剂;K负载可提高其催化活性,其中10%K/LiCoO2具有最低的PM起燃温度(246℃)和最大NOx→N2转化率(35.9%);催化剂表面生成的O2-/O-活性氧物种以及较强的NOx吸附存储能力可能是K/LiCoO2催化活性提高的原因.     

润湿剂促进燃煤细颗粒声波团聚脱除的实验研究

在声波团聚室中研究了润湿剂液滴与细颗粒碰撞团聚脱除特性,提出了一种利用润湿剂促进细颗粒在声波场中捕集的新方法。结果表明,不同润湿剂溶液对细颗粒在声波场中的团聚脱除效果存在较大差异,采用JFC和FS-310润湿剂溶液时,细颗粒分级脱除效率与采用水时的分级脱除效率相近。而SDS和Silanol w22溶液,则可有效提高细颗粒在各粒径段的分级脱除效率。细颗粒在声波场中的脱除效率与润湿剂润湿性能具有很好的相关性,随润湿剂对细颗粒相对接触角增大而降低,在声压级为150 dB时,相对接触角由83°降低到0°,细颗粒脱除效率提高了18%,在无声场作用下,脱除效率仅提高了5%。细颗粒脱除效率随声压级的增大而提高,在低声压级条件下,添加润湿剂可有效提高细颗粒脱除效率,声压级在130 dB时,添加SDS溶液液滴后细颗粒脱除效率比声场单独作用时的脱除效率提高了25%。表明添加润湿剂可有效提高细颗粒在声波场中的团聚脱除效率,实现在低声压级条件下,获得高的细颗粒脱除效率。     

Development of novel graphene-like layered hexagonal boron nitride for adsorptive removal of antibiotic gatifloxacin from aqueous solution

Graphene-like layered hexagonal boron nitride (g-BN) was prepared and characterized. The performance of using g-BN as an adsorbent for removal of fluoroquinolone antibiotic gatifloxacin (GTF) from aqueous solution was evaluated. g-BN showed an excellent adsorption capability with notable GTF adsorption ratio of more than 90%. Data of equilibrium adsorption of GTF onto g-BN at different temperatures were represented by Langmuir, Freundlich and Tempkin isotherm models, and Langmuir exhibited the best fitting with the maximum adsorption capacity of 88.5 mg·g^?1 at 288 K. GTF adsorption was insignificantly affected by solution pH. Competitive role of Na⁺ and Ca²⁺ in the solution inhibited the adsorption of GTF and decreased the adsorption capacity a bit. The adsorption process was spontaneous and exothermic. The adsorption was probably governed by π–π interaction between GTF and g-BN, and electrostatic interaction may also exist in the adsorption process.     

A Luminescent Hypercrosslinked Conjugated Microporous Polymer for Efficient Removal and Detection of Mercury Ions

A hypercrosslinked conjugated microporous polymer (HCMP‐1) with a robustly efficient absorption and highly specific sensitivity to mercury ions (Hg²⁺) is synthesized in a one‐step Friedel–Crafts alkylation of cost‐effective 2,4,6‐trichloro‐1,3,5‐triazine and dibenzofuran in 1,2‐dichloroethane. HCMP‐1 has a moderate Brunauer–Emmett–Teller specific surface (432 m² g⁻¹), but it displays a high adsorption affinity (604 mg g⁻¹) and excellent trace efficiency for Hg²⁺. The π–π* electronic transition among the aromatic heterocyclic rings endows HCMP‐1 a strong fluorescent property and the fluorescence is obviously weakened after Hg²⁺ uptake, which makes the hypercrosslinked conjugated microporous polymer a promising fluorescent probe for Hg²⁺ detection, owning a super‐high sensitivity (detection limit 5 × 10⁻⁸ mol L⁻¹).