Use of Cyclodextrins as An Environmentally Friendly Extracting Agent in Organic Aged-contaminated Soil Remediation

The removal of Polycyclic Aromatic Hydrocarbons (PAHs) from soil using pure water is quite ineffective due to␣their low aqueous solubility. Most of present processes are based on organic cosolvents or surfactants, leading to potential environmental hazard. Addition of cyclodextrin (CD) in aqueous washing solutions has been shown to␣increase the removal efficiency several times, while being non-toxic agents. Herein are investigated the effectiveness of cyclodextrins to remove PAHs occurring in industrially aged-contaminated soil. β-cyclodextrin (BCD), hydroxypropyl-β-cyclodextrin (HPCD) and methyl-β-cyclodextrin (MCD) solutions were used for soil flushing in column test or batch experiments to evaluate some influent parameters that can significantly increase the removal efficiency. The process parameters chosen were CD concentration, ratio of washing solution volume to soil weight, and temperature of washing solution. These parameters were found to have a significant and almost linear effect on PAHs removal from the contaminated soil, except the temperature where no significant enhancement in PAHs extraction was observed for temperature range from 5 to 35 °C. Removal capacity of HPCD and MCD was higher than BCD one. The PAHs extraction enhancement factor compared to water was about 200.     

Quantifying dithiothreitol displacement of functional ligands from gold nanoparticles

Dithiothreitol (DTT)-based displacement is widely utilized for separating ligands from their gold nanoparticle (AuNP) conjugates, a critical step for differentiating and quantifying surface-bound functional ligands and therefore the effective surface density of these species on nanoparticle-based therapeutics and other functional constructs. The underlying assumption is that DTT is smaller and much more reactive toward gold compared with most ligands of interest, and as a result will reactively displace the ligands from surface sites thereby enabling their quantification. In this study, we use complementary dimensional and spectroscopic methods to characterize the efficiency of DTT displacement. Thiolated methoxypolyethylene glycol (SH-PEG) and bovine serum albumin (BSA) were chosen as representative ligands. Results clearly show that (1) DTT does not completely displace bound SH-PEG or BSA from AuNPs, and (2) the displacement efficiency is dependent on the binding affinity between the ligands and the AuNP surface. Additionally, the displacement efficiency for conjugated SH-PEG is moderately dependent on the molecular mass (yielding efficiencies ranging from 60 to 80?% measured by ATR-FTIR and ≈90?% by ES-DMA), indicating that the displacement efficiency for SH-PEG is predominantly determined by the S–Au bond. BSA is particularly difficult to displace with DTT (i.e., the displacement efficiency is nearly zero) when it is in the so-called normal form. The displacement efficiency for BSA improves to 80?% when it undergoes a conformational change to the expanded form through a process of pH change or treatment with a surfactant. An analysis of the three-component system (SH-PEG?+?BSA?+?AuNP) indicates that the presence of SH-PEG decreases the displacement efficiency for BSA, whereas the displacement efficiency for SH-PEG is less impacted by the presence of BSA.

Decontamination Efficiency of Thermal,Photothermal, Microwave,and Steam Treatments for Biocontaminated Household Textiles

With the outbreak of the COVID-19 pandemic, textile laundering hygiene has proved to be a fundamental measure in preventing the spread of infections. The first part of our study evaluated the decontamination efficiency of various treatments (thermal, photothermal, and microwave) for bio contaminated textiles. The effects on textile decontamination of adding saturated steam into the drum of a household textile laundering machine were investigated and evaluated in the second part of our study. The results show that the thermal treatment, conducted in a convection heating chamber, provided a slight reduction in efficiency and did not ensure the complete inactivation of Staphylococcus aureus on cotton swatches. The photothermal treatment showed higher reduction efficiency on contaminated textile samples, while the microwave treatment (at 460 W for a period of 60 s) of bio contaminated cotton swatches containing higher moisture content provided satisfactory bacterial reduction efficiency (more than 7 log steps). Additionally, the treatment of textiles in the household washing machine with the injection of saturated steam into the washing drum and a mild agitation rhythm provided at least a 7 log step reduction in S. aureus. The photothermal treatment of bio contaminated cotton textiles showed promising reduction efficiency, while the microwave treatment and the treatment with saturated steam proved to be the most effective.     

DETERGENT EFFICIENCY OF WATER/NONIONIC SURFACTANT/HYDROCARBON SYSTEMS. PART II: INFLUENCE OF ELECTROLYTES

Washing efficiency of water/nonionic surfactant/hydrocarbon systems under the presence of different types of electrolytes has been evaluated, The influence of different parameters such as pH value, washing time, electrolyte concentration, etc., have also been considered. The results showed that the enhancement on washing efficiency promoted by alkaline electrolytes was higher than that promoted by neutral electrolytes.     

Using Surfactant System to Wash a Polluted Soil by Petroleum Derivatives in Egyptian Abu Madi Fields in Terms of Emulsification

The exploration and production activities of the natural gas in Abu Madi region (in middle delta) progressed in the last decade. The condensate hydrocarbon and formation water are bi‐products produced during the natural gas industry. The accompanied water contains 10–15% condensate (gasoline). This water with gasoline was drained into the Shehab El‐Din drain. The farmers were used this water to irrigate their fields. Great areas of the fields were out of order of planting as the result of gasoline pollution. This work concentrates on washing the polluted soil using locally prepared surfactant (LABSA‐Na) in the washing process. The soil sample was picked up from the Abu Madi field and was divided into pots (four pots for each treatment). The experiment was designed on the basis of polluting the soil by gasoline (condensate) from 1 to 10%. The washing process was carried out in presence of 0.1, 0.3, and 0.5% surfactant solutions. The control and blank sample were taken in consideration. The washed and the latent oil percentages were determined using the spectrophotometric method. After polluting and washing the soil, the pots were fertilized and planted by Zea Mays. The pots were irrigated twice a week. The length of plants was followed up. The obtained results cleared that, the efficiency of washing process increases with increasing of the pollutant percentage and also with increasing of surfactant concentration. The maximum washed oil (gasoline) was obtained at 10% gasoline and 0.5% surfactant concentration. The length of plants after 21 days of planting were; 0 (no planting), 24, 34, 39, 54, and 57 cm against polluted soil and planted (control) washed soil by water only; washed soil by 0.1%; washed soil by 0.3%; washed soil by 0.5% and no polluted soil (blank) respectively. These data revealed that, removing the hydrocarbon from the soil by washing using surfactants is the most effective method as the result of solubilization and emulsification of the hydrocarbon by surfactant which make it more removable.     

Comparison of pesticides levels in grape skin and in the whole grape by a new liquid chromatographic multiresidue methodology

The increasing interest in the study of pesticides in grapes is justified from an enological point of view, since some pesticides can interfere with fermentative microflora used in wine production, as well as, with the consumer’ safety. Considering that washing grapes before consumption is the standard procedure, the study of the effect of washing on the residue concentration is required to assess real consumer exposure. In this work, pesticide mobility in grapes was studied, by comparing their residual concentration in the skin with that of the whole grape. The efficiency of water washing to remove pesticides from grape skins was also evaluated.One variety of grapes from the Northern region of Portugal, Trajadura, sampled at two maturation periods of the 2001 crop, were analysed by a new validated methodology involving liquid chromatography with diode array detection.It was concluded that, although there were no significant differences between some pesticide levels found in the whole grape (skin and pulp) and in the grape skin, pyrimethanil was preferably found in the pulp, while metalaxyl was detected in the skin but not in the whole grape.The removal of pesticides from grapes by washing did not exceed 70% (procymidone). Never the less, it was concluded that consumer intake of the pesticides from grapes studied in this work should be significantly decreased as a result of water washing of the grapes.The concentration levels found for the pesticide residues were below both the Portuguese and the FAO Maximum Residue Levels (MRLs), thus causing no problems in terms of food safety.     

Displacement washing of soda rapeseed pulp

The paper deals with the displacement washing of unbleached pulp cooked from rapeseed straw by soda pulping under laboratory conditions. Pulp fibres were characterised by their average length, as well as by effective specific volume and surface. Using the step function input change method, the washing breakthrough curves measured for alkali lignin as a tracer were described by the dispersed plug flow model containing a dimensionless criterion, the Péclet number. Besides the wash yield, the dispersion coefficient as well as the mean residence time and space time were evaluated. Preliminary results obtained for soda rapeseed pulp were compared with those for kraft hardwood (beech) and softwood (spruce, pine) pulps published earlier. The wash yield measured for soda pulp was found to be lower than that for hardwood and softwood pulps which manifested lower hydraulic resistance. The presence of silique valves in rapeseed straw resulted in lower mean residence time of lignin removed from the pulp bed in comparison with pulp manufactured from stalks only.     

Influence of the washing process on the aligning capability of a nematic liquid crystal on polymer surfaces

The influence of washing processes on the liquid crystal (LC) aligning capability on rubbed polyimide (PI) surfaces containing the CONH moiety were investigated. The induced optical retardation from a non-washing process on a rubbed PI surface is larger than when the washing processes are included. The pretilt angles in 4-n-pentyl-4'-cyanobiphenyl (5CB) were decreased by the washing process. The polar anchoring energy of 5CB was decreased by the washing processes on a weakly rubbed PI surface. The surface order parameter S_S of 5CB strongly depends on the rubbing strength and washing materials. Consequently, the LC aligning capability may be strongly attributed to the polymer characteristics and the washing processes.     

Research and development of method for potassium acetate of high purity

Crystallization of potassium acetate from aqueous solutions, an effect of product yield and washing of its crystals on an efficiency of purification were investigated. Behavior of KCH₃COO·1.5H₂O was studied in heating. Based on data of the study a technological scheme of producing anhydrous potassium acetate of high purity was developed.     

Extraction of Cupric Ions with Ionic Liquids Containing Polypyridine‐type Small Molecules or Peripherally Pyridine‐modified Dendrimers

The hydrophobic ionic liquid N‐butyl‐N‐methylpyrrolidinium bis((trifluoromethyl)sulfonyl)amide (BMP‐TFSA IL), which contains a series of flexible ionophores of polypyridine‐type small molecules or two rigid ionophores of peripherally pyridine‐modified PAMAM dendrimers, was used to extract cupric ions from aqueous solutions. The polypyridine‐type ionophores show good selectivity toward cupric ions at pH 2. The selectivity is affected by the spacing between the two amino groups. However, the pyridine‐modified dendrimers showed poor selectivity, although their extraction efficiency still depended on the pH of the aqueous solution. The ionic liquids that contained small molecular ionophores and their dendrimer analogs were reused after acid washing or electrochemical reduction. During acid washing, the nitrogen atoms of the ionophores were protonated to release the cupric ions into the aqueous phase, and the copper atoms were deposited onto the electrode surface during the electrochemical reduction accompanied by the regeneration of the ionophores.     

Determination of the clean‐up efficiency of the solid‐phase extraction of rosemary extracts: Application of full‐factorial design in hyphenation with Gaussian peak fit function

We present a novel method for the quantitative determination of the clean‐up efficiency to provide a calculated parameter for peak purity through iterative fitting in conjunction with design of experiments. Rosemary extracts were used and analyzed before and after solid‐phase extraction using a self‐fabricated mixed‐mode sorbent based on poly(N‐vinylimidazole/ethylene glycol dimethacrylate). Optimization was performed by variation of washing steps using a full three‐level factorial design and response surface methodology. Separation efficiency of rosmarinic acid from interfering compounds was calculated using an iterative fit of Gaussian‐like signals and quantifications were performed by the separate integration of the two interfering peak areas. Results and recoveries were analyzed using Design‐Expert® software and revealed significant differences between the washing steps. Optimized parameters were considered and used for all further experiments. Furthermore, the solid‐phase extraction procedure was tested and compared with commercial available sorbents. In contrast to generic protocols of the manufacturers, the optimized procedure showed excellent recoveries and clean‐up rates for the polymer with ion exchange properties. Finally, rosemary extracts from different manufacturing areas and application types were studied to verify the developed method for its applicability. The cleaned‐up extracts were analyzed by liquid chromatography with tandem mass spectrometry for detailed compound evaluation to exclude any interference from coeluting molecules.     

Magnetic-based purification system with simultaneous sample washing and concentration

Simultaneous washing and concentration of magnetic microparticles was demonstrated using a rotational magnetic system under a continuous-flow condition. The rotation of periodically arranged permanent magnets close to a fluidic channel carrying a suspension of magnetic particles allows the trapping and releasing of particles along the fluidic channel in a periodic manner. Each trapping and releasing event resembles one washing cycle in conventional biological assays. Concentration efficiencies of 99.75?±?0.083% at a flow rate of 200 µl/min and 88.10?±?3.17% at a flow rate of 1,000 µl/min and a purification efficiency of 99.10?±?4.3% at a flow rate of 900 µl/min were achieved.     

Preparation and Evaluation of Theophylline Sustained Release Microcapsules Using Coacervation

Preparation of sustained release dosage forms is one of the main objectives in drug formulation. Theophylline that has a narrow therapeutic index, making it a good choice to prepare a sustained release dosage form. Theophylline sustained release microcapsules were prepared by applying the coacervation method. The effect of the type and ratio of polymers, as well as the type of washing solvents, was studied on particle size, drug loading efficiency, and in vitro drug release profile. Results showed that Eudragit RS and RL could be more suitable polymers for preparation of sustained release microcapsules of theophylline when used in ratio of 1:1 and when the washing solvent was hexane.     

Electrochromatographic behavior of silica monolithic capillaries of different skeleton sizes synthesized with a simplified and shortened sol-gel procedure

Silica monolithic capillaries (SMCs) were synthesized by a sol-gel process. First, a simplification of the synthesis was proposed by replacing the calcination and the drying steps which can have tremendous effects on chromatographic and physical properties, by a single water or methanol 2 h washing step. The efficiency of such a washing step was demonstrated and the comparison of the chromatographic and electrochromatographic properties between calcined and washed SMCs has shown that such a modification did not impair retention, efficiency, and stability of the monolith. This simplified procedure was carried out to synthesize SMCs with two different skeleton sizes. These capillaries were evaluated in electrochromatography and present high efficiencies (H = 5 microm) at least equal to the best ones reported in the literature. Furthermore, the influence of the skeleton size on the EOF of the second kind (EOF-2) was investigated with unmodified SMCs used under various experimental conditions including electrical field strength and buffer concentration. The ionic strength of the mobile phase and the applied electrical field that enable this EOF-2 were related to the size of the skeleton which was tuned by the synthesis conditions.     

Dispersion of SiO2-based nanocomposites with high performance liquid chromatography

Core-shell structured Ag/SiO2 nanocomposite has been synthesized by a cyclohexane/Igepal/water reverse micelle system. The spherical nanocomposite particles were washed and concentrated with high performance liquid chromatography (HPLC) to remove the surfactant added during synthesis. Spherical SiO2 micrometer-scale particles were packed in the HPLC column as a stationary phase for the washing and dispersing of Ag/SiO2 nanocomposite particles. Surface modification of Ag/SiO2 nanocomposite particles and SiO2 microspheres with silane coupling agent enhanced the surface charge of the particles and improved the efficiency of washing with HPLC. Well-dispersed Ag/SiO2 stable suspensions were successfully attained in ethanol/water mixed solvents after HPLC washing. The state of dispersion for the Ag/SiO2 nanocomposite suspension was systematically assessed using dynamic light scattering (DLS) and transmission electron microscope (TEM) and spin coat/atomic force microscope (AFM) analyses. The mechanism of the enabling HPLC washing protocol for SiO2-based nanoparticles is discussed.     

Preparation and characterization by surface-enhanced infrared absorption spectroscopy of silver nanoparticles formed on germanium substrates by electroless displacement

In this paper, the feasibility of applying electroless displacement to prepare silver nanoparticles (AgNPs) on the surface of germanium (Ge) substrate is demonstrated, and the performances of surfaces prepared in this manner for surface-enhanced infrared absorption (SEIRA) spectroscopy are reported. The process used to produce suitable AgNPs for SEIRA by electroless deposition is simple and effective, requiring only pretreatment of the germanium surface with hot air, immersion of the substrate in a dilute solution of silver nitrate, and washing of the resulting plate. To quantify the behavior of AgNPs on a Ge substrate and to optimize the conditions for the preparation of AgNPs on Ge substrates, a monolayer of p-nitrothiophenol (PNTP) was bonded to the surface of the AgNPs by immersion of the plate in a dilute solution of PNTP and measurement of the transmission spectrum. The factors that influenced the formation of AgNPs, and hence the SEIRA signals, included the concentration of AgNO₃, the reaction time and the temperature. Results indicated that stronger absorption bands in the SEIRA spectrum of a monolayer of PNTP were obtained if the reaction rate for the displacement of silver ions by Ge was slow. This condition was achieved by keeping the concentration of AgNO₃ and the reaction temperature low. Under the optimal conditions found in this work, an enhancement factor of approximately 100 was achieved for commonly used probe molecules in SEIRA measurements.     

The displacement efficiency and rheology of welan gum for enhanced heavy oil recovery

The displacement efficiency of welan gum on enhanced heavy oil recovery has been investigated by comparing that of xanthan gum which is commonly used for polymer flooding, and it is found that the displacement efficiency of biopolymer welan gum is higher (>7.0 % at the normal permeability) than that of xanthan gum. In‐depth rheological investigations show that both storage modulus and loss modulus of welan gum solution are higher than those of xanthan gum solutions at the same concentration, temperature and salinity. The higher displacement efficiency for enhanced heavy oil recovery by welan gum is mainly caused by its stronger ability to form aggregates. Although the molecular weight of welan gum is lower than that of xanthan gum, the aggregates of welan gum molecules help to improve the sweep efficiency. It is proposed that welan gum improves oil recovery by drawing and dragging on the residual oils which is derived from the interlinked network structures formed by the adjacent double helices in the arrangement of the zipper model. The intermolecular structures formed by zipper model are stable in high temperature and high salinity condition. Copyright © 2014 John Wiley & Sons, Ltd.     

毛细管气相色谱法分析合成聚苯硫醚醇洗液的组成

建立了一种用毛细管气相色谱法分析合成聚苯硫醚醇洗液组成的方法.其组成包括乙醇、水、对二氯苯和吡咯烷酮,采用DB-WAX毛细管气相色谱柱、TCD检测器.在优化的色谱条件下,4种醇洗液组分在选择的浓度范围内线性关系良好,相关系数（r）均不小于0.998.在高、中、低3个加标水平下,平均回收率为95.72%-118.75%,相对标准偏差（RSD）均不大于4.91%.方法的检出限（LOD）为0.51-1.74 mg/kg.方法操作简单、准确、高效快捷,适用于硫化钠法合成聚苯硫醚醇洗液中4组分的同时检测.     

Simultaneous sample washing and concentration using a "trapping-and-releasing" mechanism of magnetic beads on a microfluidic chip

Simultaneous washing and concentration of functionalized magnetic beads in a complex sample solution were demonstrated by applying a rotational magnetic actuation system to a microfluidic chip under continuous flow conditions. The rotation of periodically arranged small permanent magnets close to the fluidic channel carrying a magnetic bead suspension allows trapping and releasing of the beads along the fluidic channel in a periodical manner. Each trapping and releasing event resembles one washing cycle. A purification efficiency of magnetic beads out of a mixed magnetic and non-magnetic bead sample solution of 83±4% at a flow rate of 0.5 μL min(-1), and a magnetic bead recovery or concentration efficiency of 91±5% were achieved using a flow rate of 0.2 μL min(-1). The detection performance of the device was experimentally evaluated with two different bioassays, using either streptavidin-coated magnetic beads in combination with biotinylated fluorescent isothiocyanate (FITC), or a mouse antigen (Ag)-antibody (Ab) system.